Merge pull request 'Data provider refactor' (#11) from data-provider-refactor into master

Reviewed-on: https://gitea.micialware.ru/micialware/jap_learn/pulls/11

src/app.rs

@@ -1,21 +1,21 @@
-use chrono::NaiveDate;
+use crate::data::Id;
-use hashbrown::HashMap;
-use iced::{keyboard, window, Subscription};
-use iced_core::{Font, Size, Theme};
-use iced_core::window::Position;
-#[cfg(target_os = "linux")]
-use iced_core::window::settings::PlatformSpecific;
-use log::info;
-use rusqlite::Connection;
 use crate::data::entities::DeckSettings;
+use crate::data::entities::{WordData, WordGroup};
 use crate::data_provider::card_sets::load_sets;
 use crate::data_provider::settings::get_setting;
 use crate::data_provider::sqlite::default_connection;
 use crate::data_provider::words::{load_word_groups, load_words};
-use crate::data::entities::{ WordData, WordGroup};
-use crate::data::Id;
-use crate::navigation::{AppSettings, RootMessage, ScreenState};
 use crate::navigation::RootMessage::Keyboard;
+use crate::navigation::{AppSettings, RootMessage, ScreenState};
+use chrono::NaiveDate;
+use hashbrown::HashMap;
+use iced::{Subscription, keyboard, window};
+use iced_core::window::Position;
+#[cfg(target_os = "linux")]
+use iced_core::window::settings::PlatformSpecific;
+use iced_core::{Font, Size, Theme};
+use log::info;
+use rusqlite::Connection;
 pub const USER_FONT: Font = Font::with_name("Noto Sans JP");
 
 pub fn start() -> iced::Result {
@@ -94,9 +94,9 @@ pub fn fill_state(state: &mut AppState) {
     let groups = load_word_groups(&state.connection);
     let setting = load_settings(&state.connection);
 
-    state.dictionary = list;
+    state.dictionary = list.unwrap_or_default();
-    state.decks = sets;
+    state.decks = sets.unwrap_or_default();
-    state.word_groups = groups;
+    state.word_groups = groups.unwrap_or_default();
     state.sync_data = setting
 }
 

src/core.rs

@@ -1,3 +1,3 @@
+pub mod deck;
 pub mod kana_set;
 pub mod srs;
-pub mod deck;

src/core/deck.rs

@@ -1,13 +1,16 @@
 use crate::app::AppState;
-use crate::core::srs::{OrderMode, OrderModule, RandomSRSModule, SRSModule, SemiRandomSRSModule, WordOpenMode, WorstWordsSRSModule};
+use crate::core::srs::{
+    OrderMode, OrderModule, RandomSRSModule, SRSModule, SemiRandomSRSModule, WordOpenMode,
+    WorstWordsSRSModule,
+};
 use crate::data::entities::*;
 use crate::data_provider::card_stats::{load_stats_of_deck, update_stat_score};
 use crate::data_provider::history::push_note;
+use crate::notification::{MaybeError, NotificationData};
 use chrono::Utc;
 use parking_lot::Mutex;
 use std::sync::Arc;
 
-
 #[derive(Clone)]
 pub struct DeckData {
     pub(crate) words: Vec<WordData>,
@@ -18,24 +21,27 @@ pub struct DeckData {
     settings: DeckSettings,
 }
 impl DeckData {
-    pub fn new(settings: &DeckSettings, state: Arc<Mutex<AppState>>) -> Self {
+    pub fn new(
+        settings: &DeckSettings,
+        state: Arc<Mutex<AppState>>,
+    ) -> Result<Self, NotificationData> {
         let state_for = state.clone();
         let state_locked = state.lock();
 
-        let stats = load_stats_of_deck(settings, &state_locked.connection);
+        let stats = load_stats_of_deck(settings, &state_locked.connection)?;
         let words = stats
             .iter()
             .map(|stat| {
                 state_locked
                     .dictionary
                     .binary_search_by_key(&stat.word_id, |w| w.id)
-                    .unwrap()
+                    .expect("No word found in dictionary")
             })
             .map(|index| &state_locked.dictionary[index])
             .cloned()
             .collect();
 
-        Self {
+        Ok(Self {
             set: stats,
             words,
             current_word_index: None,
@@ -48,47 +54,37 @@ impl DeckData {
                 OrderMode::FullRandom => OrderModule::RandomSRS(RandomSRSModule::new()),
             },
             settings: settings.clone(),
-        }
+        })
     }
 
     pub fn next(&mut self) -> (WordData, CardStatistics) {
-        let index = match self.order_module.clone() {
+        let index = match self.order_module {
-            OrderModule::SemiRandomSRS(mut module) => {
+            OrderModule::SemiRandomSRS(ref mut module) => {
                 if !module.initialized {
-                    module.init(self)
+                    module.init(self.set.as_slice())
                 }
-                let index = module.next(self);
+                module.next(self.set.as_slice())
-                self.order_module = OrderModule::SemiRandomSRS(module);
-                index
             }
-            OrderModule::RandomSRS(mut module) => {
+            OrderModule::RandomSRS(ref mut module) => {
                 if !module.initialized {
-                    module.init(self)
+                    module.init(self.set.as_slice())
                 }
-                let index = module.next(self);
+                module.next(self.set.as_slice())
-                self.order_module = OrderModule::RandomSRS(module);
-                index
             }
-            OrderModule::WorstWordsSRS(mut module) => {
+            OrderModule::WorstWordsSRS(ref mut module) => {
                 if !module.initialized {
-                    module.init(self)
+                    module.init(self.set.as_slice())
                 }
-                let index = module.next(self);
+                module.next(self.set.as_slice())
-                self.order_module = OrderModule::WorstWordsSRS(module);
-                index
             }
         };
 
         self.current_word_index = Some(index);
         (self.words[index].clone(), self.set[index].clone())
     }
-    pub fn open(&mut self, status: WordOpenMode) {
+    pub fn open(&mut self, status: WordOpenMode) -> MaybeError {
-        if self.current_word_index.is_none() {
+        if let Some(index) = self.current_word_index {
-            return;
+            let word: &mut CardStatistics = &mut self.set[index];
-        }
-        let index = self.current_word_index.unwrap();
-
-        let word : &mut CardStatistics = &mut self.set[index];
             let old_score = word.score;
             word.update(status);
             let new_score = word.score;
@@ -104,7 +100,7 @@ impl DeckData {
                     module.open(status, index, word);
                 }
             }
-        update_stat_score(word, &self.state.lock().connection);
+            update_stat_score(word, &self.state.lock().connection)?;
             let _ = push_note(
                 self.settings.id,
                 HistoryItem {
@@ -116,8 +112,10 @@ impl DeckData {
                 },
             );
         }
+
+        Ok(())
+    }
     pub fn len(&self) -> usize {
         self.set.len()
     }
 }
-

src/core/srs.rs

@@ -1,9 +1,8 @@
-use crate::core::deck::DeckData;
+use crate::data::entities::CardStatistics;
 use rand::distr::weighted::WeightedIndex;
 use rand::prelude::ThreadRng;
 use rand::prelude::{Distribution, SliceRandom};
 use rand::rng;
-use crate::data::entities::CardStatistics;
 
 const MAX_HISTORY_LEN: usize = 20;
 const MAX_HISTORY_LEN_PART: f32 = 0.33;
@@ -29,9 +28,9 @@ pub enum OrderModule {
     WorstWordsSRS(WorstWordsSRSModule),
 }
 pub trait SRSModule {
-    fn next(&mut self, set: &mut DeckData) -> usize;
+    fn next(&mut self, set: &[CardStatistics]) -> usize;
     fn open(&mut self, status: WordOpenMode, index: usize, updated_word: &CardStatistics);
-    fn init(&mut self, set: &mut DeckData);
+    fn init(&mut self, set: &[CardStatistics]);
 }
 #[derive(Clone)]
 pub struct RandomSRSModule {
@@ -47,11 +46,11 @@ impl RandomSRSModule {
     }
 }
 impl SRSModule for RandomSRSModule {
-    fn next(&mut self, set: &mut DeckData) -> usize {
+    fn next(&mut self, set: &[CardStatistics]) -> usize {
         match self.basket.pop() {
             Some(index) => index,
             None => {
-                self.basket = (0..set.words.len()).collect::<Vec<usize>>();
+                self.basket = (0..set.len()).collect::<Vec<usize>>();
                 self.basket.shuffle(&mut rand::rng());
                 self.basket.pop().expect("empty basket")
             }
@@ -60,9 +59,9 @@ impl SRSModule for RandomSRSModule {
 
     fn open(&mut self, _: WordOpenMode, _: usize, _: &CardStatistics) {}
 
-    fn init(&mut self, set: &mut DeckData) {
+    fn init(&mut self, set: &[CardStatistics]) {
         self.initialized = true;
-        self.basket = (0..set.set.len()).collect::<Vec<usize>>();
+        self.basket = (0..set.len()).collect::<Vec<usize>>();
         self.basket.shuffle(&mut rand::rng())
     }
 }
@@ -84,7 +83,7 @@ impl SemiRandomSRSModule {
     }
 }
 impl SRSModule for SemiRandomSRSModule {
-    fn next(&mut self, set: &mut DeckData) -> usize {
+    fn next(&mut self, set: &[CardStatistics]) -> usize {
         let index = self.last_weights.sample(&mut self.generator);
 
         if self.history.contains(&index) && self.history.len() != 1 {
@@ -104,18 +103,17 @@ impl SRSModule for SemiRandomSRSModule {
             .update_weights(&[(index, &new_weight)])
             .expect("update weights error");
     }
-    fn init(&mut self, set: &mut DeckData) {
+    fn init(&mut self, set: &[CardStatistics]) {
         self.initialized = true;
         let weights = set
-            .set
             .iter()
             .map(|s| (100.0 / s.calculated_score()).powf(2.0) * 2.0)
             .collect::<Vec<f32>>();
-        self.last_weights = WeightedIndex::new(weights).unwrap();
+        self.last_weights = WeightedIndex::new(weights).expect("Incorrect weights update");
     }
 }
 impl SemiRandomSRSModule {
-    fn history_len(&self, set: &DeckData) -> usize {
+    fn history_len(&self, set: &[CardStatistics]) -> usize {
         ((set.len() as f32 * MAX_HISTORY_LEN_PART) as usize).clamp(1, MAX_HISTORY_LEN)
     }
 }
@@ -129,7 +127,7 @@ pub struct WorstWordsSRSModule {
     rounds_count: u8,
 }
 impl SRSModule for WorstWordsSRSModule {
-    fn next(&mut self, set: &mut DeckData) -> usize {
+    fn next(&mut self, set: &[CardStatistics]) -> usize {
         if self.rounds_remaining == 0 {
             self.fill_pool(set);
             self.rounds_remaining = self.rounds_count;
@@ -147,7 +145,7 @@ impl SRSModule for WorstWordsSRSModule {
 
     fn open(&mut self, _: WordOpenMode, _: usize, _: &CardStatistics) {}
 
-    fn init(&mut self, _: &mut DeckData) {
+    fn init(&mut self, _: &[CardStatistics]) {
         self.initialized = true;
     }
 }
@@ -162,17 +160,12 @@ impl WorstWordsSRSModule {
             queue: vec![],
         }
     }
-    fn fill_pool(&mut self, set: &DeckData) {
+    fn fill_pool(&mut self, set: &[CardStatistics]) {
-        let mut sorted = set
+        let mut sorted = set.iter().enumerate().collect::<Vec<_>>();
-            .set
+        sorted.sort_by_key(|c| c.1.score);
-            .clone()
-            .into_iter()
-            .zip(0..set.set.len())
-            .collect::<Vec<_>>();
-        sorted.sort_by_key(|c| c.0.score);
         let mut worst = sorted[0..self.pool_size]
             .iter()
-            .map(|(_, index)| *index)
+            .map(|(index, _)| *index)
             .collect::<Vec<usize>>();
         worst.shuffle(&mut rand::rng());
         self.pool = worst;

src/data.rs

@@ -1,12 +1,12 @@
 pub mod entities;
 
+use rusqlite::ToSql;
+use rusqlite::types::{FromSql, FromSqlError, FromSqlResult, ToSqlOutput, ValueRef};
 use std::fmt::{Display, Formatter};
 use std::num::ParseIntError;
 use std::str::FromStr;
-use rusqlite::ToSql;
-use rusqlite::types::{FromSql, FromSqlError, FromSqlResult, ToSqlOutput, ValueRef};
 
-#[derive(Clone, PartialEq, Eq, Debug, Hash, Copy, Ord, PartialOrd)]
+#[derive(Clone, PartialEq, Eq, Debug, Hash, Copy, Ord, PartialOrd, Default)]
 pub struct Id(pub(crate) u32);
 pub const INVALID_ID: Id = Id(0);
 impl FromStr for Id {

src/data/entities.rs

@@ -105,12 +105,15 @@ impl DeckSettings {
                                 .iter()
                                 .find(|g| g.id == word.group_id)
                                 .cloned()
-                                .unwrap()
+                                .expect("No group id")
                                 .name,
                         );
 
                     let result = engine.eval_ast_with_scope::<bool>(&mut scope, &ast);
-                    result.is_ok() && result.unwrap()
+                    if let Ok(result) = result {
+                        return result;
+                    }
+                    false
                 })
                 .map(|(index, _)| index)
                 .collect();

src/data_provider/card_sets.rs

@@ -1,12 +1,14 @@
 use crate::core::srs::OrderMode;
 
 use crate::data::entities::DeckSettings;
+use crate::notification::NotificationData::{DbLoadError, DbSaveError};
+use crate::notification::{MaybeError, NotificationData};
 use rusqlite::Connection;
 
-pub fn load_sets(connection: &Connection) -> Vec<DeckSettings> {
+pub fn load_sets(connection: &Connection) -> Result<Vec<DeckSettings>, NotificationData> {
     let mut stmt = connection
         .prepare("SELECT id, name, forward, backward, filter FROM card_set")
-        .unwrap();
+        .expect("Failed to prepare state query");
     let iter = stmt
         .query_map([], |row| {
             Ok(DeckSettings {
@@ -19,17 +21,14 @@ pub fn load_sets(connection: &Connection) -> Vec<DeckSettings> {
                 open_mode: OrderMode::Default,
             })
         })
-        .unwrap();
+        .map_err(|_| DbLoadError)?;
 
-    let mut buffer = vec![];
+    let mut buffer = Vec::with_capacity(16);
-    for word in iter {
+    iter.filter_map(|res| res.ok()).for_each(|i| buffer.push(i));
-        buffer.push(word.unwrap());
+    Ok(buffer)
-    }
-
-    buffer
 }
 
-pub fn add_set(set: &mut DeckSettings, connection: &Connection) {
+pub fn add_set(set: &mut DeckSettings, connection: &Connection) -> MaybeError {
     let index : u32 = connection
         .query_row(
             "INSERT INTO card_set (name, forward, backward, filter) VALUES (?1, ?2, ?3, ?4) RETURNING id",
@@ -41,14 +40,15 @@ pub fn add_set(set: &mut DeckSettings, connection: &Connection) {
             ),
             |row| row.get(0)
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
 
     set.id = index.into();
+    Ok(())
 }
 
-pub fn update_deck(set: &mut DeckSettings, connection: &Connection) {
+pub fn update_deck(set: &mut DeckSettings, connection: &Connection) -> MaybeError {
     if !set.id.is_valid() {
-        add_set(set, connection);
+        add_set(set, connection)?;
     } else {
         connection
             .execute(
@@ -61,15 +61,17 @@ pub fn update_deck(set: &mut DeckSettings, connection: &Connection) {
                     &set.id
                 ),
             )
-            .unwrap();
+            .map_err(|_| DbSaveError)?;
     }
+    Ok(())
 }
 
-pub fn delete_set(set: &DeckSettings, connection: &Connection) {
+pub fn delete_set(set: &DeckSettings, connection: &Connection) -> MaybeError {
     if !set.id.is_valid() {
-        return;
+        return Err(DbSaveError);
     }
     connection
         .execute("DELETE FROM card_set WHERE id = ?1", (&set.id,))
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }

src/data_provider/card_stats.rs

@@ -1,12 +1,17 @@
+use crate::data::entities::{CardStatistics, DeckSettings};
+use crate::notification::NotificationData::{DbLoadError, DbSaveError};
+use crate::notification::{MaybeError, NotificationData};
+use log::info;
 use rusqlite::{Connection, params};
 use std::time::Instant;
-use log::info;
-use crate::data::entities::{CardStatistics, DeckSettings};
 
-pub fn load_stats_of_deck(set: &DeckSettings, connection: &Connection) -> Vec<CardStatistics> {
+pub fn load_stats_of_deck(
+    set: &DeckSettings,
+    connection: &Connection,
+) -> Result<Vec<CardStatistics>, NotificationData> {
     let mut stmt = connection
         .prepare("SELECT id, word_id, score, last_opened FROM card_stats WHERE set_id = ?1")
-        .unwrap();
+        .expect("Failed to prepare state query");
     let iter = stmt
         .query_map((set.id,), |row| {
             Ok(CardStatistics {
@@ -17,19 +22,19 @@ pub fn load_stats_of_deck(set: &DeckSettings, connection: &Connection) -> Vec<Ca
                 last_open: row.get(3)?,
             })
         })
-        .unwrap();
+        .map_err(|_| DbLoadError)?;
 
-    let mut buffer = vec![];
+    let mut buffer = Vec::with_capacity(512);
-    for word in iter {
+    iter.filter_map(|res| res.ok()).for_each(|i| buffer.push(i));
-        buffer.push(word.unwrap());
-    }
 
-    buffer
+    Ok(buffer)
 }
 
-pub fn add_stat_list(stats: &mut [CardStatistics], connection: &mut Connection) {
+pub fn add_stat_list(stats: &mut [CardStatistics], connection: &mut Connection) -> MaybeError {
     let time = Instant::now();
-    let tx = connection.transaction().unwrap();
+    let tx = connection
+        .transaction()
+        .expect("Failed to create transaction");
     let count = stats.len();
 
     {
@@ -37,7 +42,7 @@ pub fn add_stat_list(stats: &mut [CardStatistics], connection: &mut Connection)
             .prepare(
                 "INSERT INTO card_stats (word_id, set_id, score, last_opened) VALUES (?1, ?2, ?3, ?4)",
             )
-            .unwrap();
+            .expect("Failed to prepare state query");
 
         for stat in stats.iter() {
             stmt.execute(params![
@@ -46,12 +51,12 @@ pub fn add_stat_list(stats: &mut [CardStatistics], connection: &mut Connection)
                 stat.score,
                 stat.last_open.timestamp()
             ])
-            .unwrap();
+            .map_err(|_| DbSaveError)?;
         }
     }
 
     let last_index: u32 = tx.last_insert_rowid() as u32;
-    tx.commit().unwrap();
+    tx.commit().expect("Failed to commit");
 
     let start_index = last_index - (count as u32) + 1;
 
@@ -60,9 +65,10 @@ pub fn add_stat_list(stats: &mut [CardStatistics], connection: &mut Connection)
     }
 
     info!("Added {} cards for {:?}", stats.len(), time.elapsed());
+    Ok(())
 }
 
-pub fn update_stat_score(stat: &CardStatistics, connection: &Connection) {
+pub fn update_stat_score(stat: &CardStatistics, connection: &Connection) -> MaybeError {
     let time = Instant::now();
 
     connection
@@ -70,13 +76,14 @@ pub fn update_stat_score(stat: &CardStatistics, connection: &Connection) {
             "UPDATE card_stats SET score = ?1, last_opened = ?2 WHERE id = ?3",
             (&stat.score, &stat.last_open.timestamp(), &stat.id),
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
     info!("Updated stat: {}", time.elapsed().as_millis());
+    Ok(())
 }
 
-pub fn delete_stats(stat: &[CardStatistics], connection: &Connection) {
+pub fn delete_stats(stat: &[CardStatistics], connection: &Connection) -> MaybeError {
     if stat.is_empty() {
-        return;
+        return Ok(());
     }
     let ids = stat
         .iter()
@@ -88,5 +95,6 @@ pub fn delete_stats(stat: &[CardStatistics], connection: &Connection) {
             format!("DELETE FROM card_stats WHERE id in ({ids})").as_str(),
             (),
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }

src/data_provider/history.rs

@@ -1,9 +1,9 @@
 use crate::core::srs::WordOpenMode;
-use crate::data::entities::HistoryItem;
 use crate::data::Id;
+use crate::data::entities::HistoryItem;
 use crate::fs::*;
-use crate::notification::NotificationData;
 use crate::notification::NotificationData::PermissionDenied;
+use crate::notification::{MaybeError, NotificationData};
 use chrono::DateTime;
 use std::fs::{File, OpenOptions};
 use std::io::Write;
@@ -15,18 +15,20 @@ pub fn get_history_of_set(id: Id) -> Result<Vec<HistoryItem>, NotificationData>
     let head = app_dir.clone().join(format!("set_{}_history.csv", id));
     let mut lines = Vec::new();
 
-    append_lines_if_exists(head, &mut lines);
+    append_lines_if_exists(head, &mut lines)?;
     lines.reverse();
     Ok(parse_history_items(lines))
 }
 
-fn append_lines_if_exists(path: PathBuf, lines: &mut Vec<String>) {
+fn append_lines_if_exists(path: PathBuf, lines: &mut Vec<String>) -> MaybeError {
     if path.exists() {
-        let reader = BufReader::new(File::open(path).unwrap());
+        let reader = BufReader::new(File::open(path).map_err(|_| PermissionDenied)?);
-        for line in reader.lines() {
+        reader
-            lines.push(line.unwrap());
+            .lines()
-        }
+            .map_while(Result::ok)
+            .for_each(|i| lines.push(i));
     }
+    Ok(())
 }
 
 fn parse_history_items(strings: Vec<String>) -> Vec<HistoryItem> {
@@ -37,12 +39,13 @@ fn parse_history_items(strings: Vec<String>) -> Vec<HistoryItem> {
             if id.is_err() {
                 continue;
             }
-            let id = id.unwrap();
+            let id = id.unwrap_or_default();
             if !id.is_valid() {
                 continue;
             }
             items.push(HistoryItem {
-                timestamp: DateTime::from_timestamp(time.parse().unwrap_or_default(), 0).unwrap_or_default(),
+                timestamp: DateTime::from_timestamp(time.parse().unwrap_or_default(), 0)
+                    .unwrap_or_default(),
                 word_id: id,
                 mode: match mode.parse::<u8>().unwrap_or_default() {
                     2 => WordOpenMode::Hard,
@@ -59,7 +62,7 @@ fn parse_history_items(strings: Vec<String>) -> Vec<HistoryItem> {
     items
 }
 
-pub fn push_note(set_id: Id, item: HistoryItem) -> Result<(), NotificationData> {
+pub fn push_note(set_id: Id, item: HistoryItem) -> MaybeError {
     let app_dir = history_dir()?;
     let path = app_dir.clone().join(format!("set_{}_history.csv", set_id));
 
@@ -84,5 +87,3 @@ pub fn push_note(set_id: Id, item: HistoryItem) -> Result<(), NotificationData>
     writeln!(&mut file, "{}", line_str).map_err(|_| PermissionDenied)?;
     Ok(())
 }
-
-

src/data_provider/import.rs

@@ -1,4 +1,6 @@
+use crate::helpers::into_result;
 use crate::notification::NotificationData;
+use crate::notification::NotificationData::IncorrectAnkiFile;
 use hashbrown::HashMap;
 use log::info;
 use rusqlite::Connection;
@@ -26,41 +28,38 @@ pub struct ImportNote {
 pub fn load_groups(connection: &Connection) -> Result<ImportData, NotificationData> {
     let json_models: String = connection
         .query_one("select models from col", (), |row| row.get(0))
-        .map_err(|_| NotificationData::IncorrectAnkiFile)?;
+        .map_err(|_| IncorrectAnkiFile)?;
-    let raw: Value = serde_json::from_str(json_models.as_str())
+    let raw: Value = serde_json::from_str(json_models.as_str()).map_err(|_| IncorrectAnkiFile)?;
-        .map_err(|_| NotificationData::IncorrectAnkiFile)?;
     let sets = raw.as_object();
     if let Some(sets) = sets {
         let mut total_data = ImportData(vec![]);
 
         let mut count_stmt = connection
             .prepare("select mid, count(id) from notes group by mid")
-            .map_err(|_| NotificationData::IncorrectAnkiFile)?;
+            .map_err(|_| IncorrectAnkiFile)?;
 
         let counts = count_stmt
             .query_map([], |row| Ok((row.get(0)?, row.get(1)?)))
-            .unwrap()
+            .map_err(|_| IncorrectAnkiFile)?
-            .map(|x| x.unwrap())
+            .filter_map(|x| x.ok())
             .collect::<Vec<(i64, i64)>>();
 
         for (_, collection) in sets {
             let fields_property = collection.get("fields");
             if let Some(fields_property) = fields_property {
-                let fields = fields_property
+                let fields = into_result(fields_property.as_array(), IncorrectAnkiFile)?
-                    .as_array()
-                    .unwrap()
                     .iter()
                     .filter_map(|x| x.get("name"))
                     .map(|x| x.as_str().unwrap().to_string())
                     .collect();
                 let id = collection.get("id");
-                if id.is_none() {
+                if id.is_none() || id.unwrap().as_u64().is_none() {
-                    return Err(NotificationData::IncorrectAnkiFile);
+                    return Err(IncorrectAnkiFile);
                 }
                 let id = id.unwrap().as_u64().unwrap();
                 let name = collection.get("name");
-                if name.is_none() {
+                if name.is_none() || name.unwrap().as_str().is_none() {
-                    return Err(NotificationData::IncorrectAnkiFile);
+                    return Err(IncorrectAnkiFile);
                 }
                 let name = name.unwrap().as_str().unwrap().to_string();
 
@@ -79,15 +78,18 @@ pub fn load_groups(connection: &Connection) -> Result<ImportData, NotificationDa
                 total_data.0.push(group);
             }
         }
-        return Ok(total_data)
+        return Ok(total_data);
     }
-    Err(NotificationData::IncorrectAnkiFile)
+    Err(IncorrectAnkiFile)
 }
 
-pub fn get_words_of_group(connection: &Connection, group_id: u64) -> Result<Vec<ImportNote>, NotificationData> {
+pub fn get_words_of_group(
+    connection: &Connection,
+    group_id: u64,
+) -> Result<Vec<ImportNote>, NotificationData> {
     let mut count_stmt = connection
         .prepare("select tags, flds from notes where mid == ?1;")
-        .map_err(|_| NotificationData::IncorrectAnkiFile)?;
+        .map_err(|_| IncorrectAnkiFile)?;
 
     Ok(count_stmt
         .query_map((group_id as i64,), |row| {
@@ -100,7 +102,7 @@ pub fn get_words_of_group(connection: &Connection, group_id: u64) -> Result<Vec<
                     .collect(),
             })
         })
-        .map_err(|_| NotificationData::IncorrectAnkiFile)?
+        .map_err(|_| IncorrectAnkiFile)?
-        .map(|x| x.unwrap())
+        .filter_map(|x| x.ok())
         .collect::<Vec<ImportNote>>())
 }

src/data_provider/settings.rs

@@ -1,10 +1,12 @@
+use crate::notification::NotificationData::{DbLoadError, DbSaveError};
+use crate::notification::{MaybeError, NotificationData};
 use rusqlite::Connection;
 
 pub fn get_setting(key: String, connection: &Connection) -> Option<String> {
     let mut stmt = connection
         .prepare("SELECT value FROM settings WHERE id = ?1")
-        .unwrap();
+        .expect("Failed to prepare statement.");
-    let mut iter = stmt.query_map((key,), |row| row.get(0)).unwrap();
+    let mut iter = stmt.query_map((key,), |row| row.get(0)).ok()?;
 
     if let Some(row) = iter.next()
         && let Ok(value) = row
@@ -15,31 +17,35 @@ pub fn get_setting(key: String, connection: &Connection) -> Option<String> {
     None
 }
 
-pub fn set_setting(key: String, value: String, connection: &Connection) {
+pub fn set_setting(key: String, value: String, connection: &Connection) -> MaybeError {
-    let current = get_settings_list(connection);
+    let current = get_settings_list(connection)?;
     if current.contains(&key) {
-        update_settings(key, value, connection);
+        update_settings(key, value, connection)?;
     } else {
-        create_settings(key, value, connection);
+        create_settings(key, value, connection)?;
     }
+
+    Ok(())
 }
 
-pub fn delete_settings(key: String, connection: &Connection) {
+pub fn delete_settings(key: String, connection: &Connection) -> MaybeError {
     connection
         .execute("DELETE FROM settings WHERE id = ?1", (&key,))
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }
 
-fn create_settings(key: String, value: String, connection: &Connection) {
+fn create_settings(key: String, value: String, connection: &Connection) -> MaybeError {
     connection
         .execute(
             "INSERT into settings (id, value) VALUES (?1, ?2)",
             (key, value),
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }
 
-fn update_settings(key: String, value: String, connection: &Connection) {
+fn update_settings(key: String, value: String, connection: &Connection) -> MaybeError {
     connection
         .execute(
             "update settings
@@ -47,11 +53,16 @@ set value = ?2
 where id = ?1",
             (key, value),
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }
 
-fn get_settings_list(connection: &Connection) -> Vec<String> {
+fn get_settings_list(connection: &Connection) -> Result<Vec<String>, NotificationData> {
-    let mut stmt = connection.prepare("SELECT id FROM settings").unwrap();
+    let mut stmt = connection
-    let iter = stmt.query_map((), |row| row.get(0)).unwrap();
+        .prepare("SELECT id FROM settings")
-    iter.map(|row| row.unwrap()).collect()
+        .expect("prepare stmt failed");
+    let iter = stmt
+        .query_map((), |row| row.get(0))
+        .map_err(|_| DbLoadError)?;
+    Ok(iter.filter_map(|i| i.ok()).collect())
 }

src/data_provider/sqlite.rs

@@ -1,23 +1,25 @@
-use rusqlite::Connection;
 use crate::fs::*;
+use rusqlite::Connection;
 
 pub fn create_db() {
     let db_file = db_path();
     if !db_file.exists() {
-        std::fs::File::create(&db_file).unwrap();
+        std::fs::File::create(&db_file).expect("Database file creation failed");
-        let connection = Connection::open(&db_file).unwrap();
+        let connection = Connection::open(&db_file).expect("Connection open failed");
-        connection.execute("PRAGMA foreign_keys = ON;", []).unwrap();
+        connection
+            .execute("PRAGMA foreign_keys = ON;", [])
+            .expect("Failed to set PRAGMA");
 
         create_tables(&connection);
     }
 }
 
 fn create_tables(conn: &Connection) {
-    make_card_set(conn).unwrap();
+    make_card_set(conn).expect("Failed to init table");
-    make_settings(conn).unwrap();
+    make_settings(conn).expect("Failed to init table");
-    make_word_group(conn).unwrap();
+    make_word_group(conn).expect("Failed to init table");
-    make_words(conn).unwrap();
+    make_words(conn).expect("Failed to init table");
-    make_card_stats(conn).unwrap();
+    make_card_stats(conn).expect("Failed to init table");
 }
 
 fn make_settings(conn: &Connection) -> Result<(), rusqlite::Error> {
@@ -51,7 +53,9 @@ fn make_card_stats(conn: &Connection) -> Result<(), rusqlite::Error> {
 
 pub fn default_connection() -> Connection {
     let db_file = db_path();
-    let connection = Connection::open(db_file).unwrap();
+    let connection = Connection::open(db_file).expect("Failed to open database");
-    connection.execute("PRAGMA foreign_keys = ON;", []).unwrap();
+    connection
+        .execute("PRAGMA foreign_keys = ON;", [])
+        .expect("Failed to set PRAGMA");
     connection
 }

src/data_provider/voice.rs

@@ -1,10 +1,10 @@
+use crate::fs::*;
+use crate::notification::NotificationData;
+use crate::notification::NotificationData::*;
 use reqwest::Client;
 use sha2::{Digest, Sha256};
 use std::fs::File;
 use std::io::BufReader;
-use crate::fs::*;
-use crate::notification::NotificationData;
-use crate::notification::NotificationData::*;
 
 pub async fn get_voice(text: &str) -> Result<BufReader<File>, NotificationData> {
     let mut path = voice_dir()?;
@@ -19,7 +19,11 @@ pub async fn get_voice(text: &str) -> Result<BufReader<File>, NotificationData>
             .send()
             .await;
 
-        let query = query.map_err(|_| VoiceVoxUnavailable)?.text().await.map_err(|_| VoiceVoxUnavailable)?;
+        let query = query
+            .map_err(|_| VoiceVoxUnavailable)?
+            .text()
+            .await
+            .map_err(|_| VoiceVoxUnavailable)?;
         // Synthesis
         let audio = client
             .post(format!("{engine_url}/synthesis?speaker=11"))
@@ -32,8 +36,12 @@ pub async fn get_voice(text: &str) -> Result<BufReader<File>, NotificationData>
             .await
             .map_err(|_| VoiceVoxUnavailable)?;
 
-        tokio::fs::write(&path, &audio).await.map_err(|_| PermissionDenied)?;
+        tokio::fs::write(&path, &audio)
+            .await
+            .map_err(|_| PermissionDenied)?;
     }
 
-    Ok(BufReader::new(File::open(path).map_err(|_| PermissionDenied)?))
+    Ok(BufReader::new(
+        File::open(path).map_err(|_| PermissionDenied)?,
+    ))
 }

src/data_provider/web_api.rs

@@ -1,19 +1,21 @@
-use std::io;
+use crate::fs::*;
+use crate::notification::NotificationData::{CompressError, PermissionDenied, WebApiUnavailable};
+use crate::notification::{MaybeError, NotificationData};
 use log::info;
+use std::io;
 use tokio::fs::{File, OpenOptions};
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use zstd::{DEFAULT_COMPRESSION_LEVEL, Decoder, Encoder};
-use crate::fs::*;
-use crate::notification::NotificationData;
-use crate::notification::NotificationData::{PermissionDenied, WebApiUnavailable};
 
 // const API_URL: &str = "http://127.0.0.1:8089/";
 const API_URL: &str = "https://learning.micialware.ru/";
 
-pub async fn send_data(id: String) -> Result<(), NotificationData> {
+pub async fn send_data(id: String) -> MaybeError {
     let db_file = db_path();
-    let data = tokio::fs::read(db_file).await.map_err(|_| WebApiUnavailable)?;
+    let data = tokio::fs::read(db_file)
-    let data = compress(data);
+        .await
+        .map_err(|_| WebApiUnavailable)?;
+    let data = compress(data)?;
 
     let api_url = API_URL.to_string();
     let id_url = format!("{api_url}upload/stream/{id}");
@@ -23,57 +25,63 @@ pub async fn send_data(id: String) -> Result<(), NotificationData> {
         .post(&id_url)
         .body(data)
         .send()
-        .await.map_err(|_| WebApiUnavailable)?
+        .await
+        .map_err(|_| WebApiUnavailable)?
         .text()
-        .await.map_err(|_| WebApiUnavailable)?;
+        .await
-    set_local_version(new_version.parse::<u32>().unwrap_or_default()).await;
+        .map_err(|_| WebApiUnavailable)?;
+    set_local_version(new_version.parse::<u32>().unwrap_or_default()).await?;
     Ok(())
 }
 
-fn compress(data: Vec<u8>) -> Vec<u8> {
+fn compress(data: Vec<u8>) -> Result<Vec<u8>, NotificationData> {
-    let mut encoder = Encoder::new(Vec::new(), DEFAULT_COMPRESSION_LEVEL).unwrap();
+    let mut encoder =
-    io::copy(&mut &data[..], &mut encoder).unwrap();
+        Encoder::new(Vec::new(), DEFAULT_COMPRESSION_LEVEL).map_err(|_| CompressError)?;
-    encoder.finish().unwrap()
+    io::copy(&mut &data[..], &mut encoder).map_err(|_| PermissionDenied)?;
+    encoder.finish().map_err(|_| CompressError)
 }
 
-pub async fn load_data(id: String, temp: bool) -> Result<(), NotificationData> {
+pub async fn load_data(id: String, temp: bool) -> MaybeError {
     let api_url = API_URL.to_string();
     let id_url = format!("{api_url}download/{id}");
     let client = reqwest::Client::new();
     let data = client
         .get(&id_url)
         .send()
-        .await.map_err(|_| WebApiUnavailable)?
+        .await
+        .map_err(|_| WebApiUnavailable)?
         .bytes()
-        .await.map_err(|_| WebApiUnavailable)?
+        .await
+        .map_err(|_| WebApiUnavailable)?
         .to_vec();
-    let data = decompress(data);
+    let data = decompress(data)?;
 
     let path = app_data_dir();
     let file_name = if temp { "data.db.tmp" } else { "data.db" };
     let db_file = path.join(file_name);
 
-    tokio::fs::write(db_file, data).await.map_err(|_| PermissionDenied)?;
+    tokio::fs::write(db_file, data)
+        .await
+        .map_err(|_| PermissionDenied)?;
 
     let version_url = format!("{API_URL}{id}/version");
     let version = client
         .get(&version_url)
         .send()
-        .await.map_err(|_| WebApiUnavailable)?
+        .await
+        .map_err(|_| WebApiUnavailable)?
         .text()
-        .await.map_err(|_| WebApiUnavailable)?;
+        .await
-    set_local_version(version.parse::<u32>().unwrap_or_default()).await;
+        .map_err(|_| WebApiUnavailable)?;
+    set_local_version(version.parse::<u32>().unwrap_or_default()).await?;
     Ok(())
 }
 
-pub fn decompress(data: Vec<u8>) -> Vec<u8> {
+pub fn decompress(data: Vec<u8>) -> Result<Vec<u8>, NotificationData> {
-    let mut decoder = Decoder::new(&data[..]).unwrap();
+    let mut decoder = Decoder::new(&data[..]).map_err(|_| CompressError)?;
     let mut decompressed = Vec::new();
-    let res = io::copy(&mut decoder, &mut decompressed);
+    io::copy(&mut decoder, &mut decompressed).map_err(|_| PermissionDenied)?;
-    if let Err(e) = res {
+    Ok(decompressed)
-        info!("{}", e);
-    }
-    decompressed
 }
 
 pub async fn first_sync() -> Result<String, NotificationData> {
@@ -95,22 +103,29 @@ pub async fn first_sync() -> Result<String, NotificationData> {
 pub async fn get_web_version(key: &str) -> Result<u32, NotificationData> {
     let id_url = format!("{API_URL}{key}/version");
     let client = reqwest::Client::new();
-    let version = client.get(&id_url).send().await.map_err(|_| WebApiUnavailable)?.text().await.map_err(|_| WebApiUnavailable)?;
+    let version = client
+        .get(&id_url)
+        .send()
+        .await
+        .map_err(|_| WebApiUnavailable)?
+        .text()
+        .await
+        .map_err(|_| WebApiUnavailable)?;
     info!("version: {}", version);
     Ok(version.parse::<u32>().unwrap_or_default())
 }
 
-pub async fn get_local_version() -> u32 {
+pub async fn get_local_version() -> Result<u32, NotificationData> {
     let file = db_meta_path();
     if file.exists() {
         let mut data = String::new();
         File::open(file.clone())
             .await
-            .unwrap()
+            .map_err(|_| PermissionDenied)?
             .read_to_string(&mut data)
             .await
-            .unwrap();
+            .map_err(|_| PermissionDenied)?;
-        return data.parse::<u32>().unwrap_or_default();
+        return Ok(data.parse::<u32>().unwrap_or_default());
     }
 
     let mut file = OpenOptions::new()
@@ -119,12 +134,14 @@ pub async fn get_local_version() -> u32 {
         .truncate(true)
         .open(file)
         .await
-        .unwrap();
+        .map_err(|_| PermissionDenied)?;
-    file.write_all("0".as_bytes()).await.unwrap();
+    file.write_all("0".as_bytes())
-    0
+        .await
+        .map_err(|_| PermissionDenied)?;
+    Ok(0)
 }
 
-pub async fn set_local_version(version: u32) {
+pub async fn set_local_version(version: u32) -> Result<(), NotificationData> {
     let file_path = db_meta_path();
     let mut file = OpenOptions::new()
         .write(true)
@@ -132,8 +149,9 @@ pub async fn set_local_version(version: u32) {
         .truncate(true)
         .open(file_path)
         .await
-        .unwrap();
+        .map_err(|_| PermissionDenied)?;
     file.write_all(version.to_string().as_bytes())
         .await
-        .unwrap();
+        .map_err(|_| PermissionDenied)?;
+    Ok(())
 }

src/data_provider/words.rs

@@ -1,8 +1,10 @@
+use crate::data::entities::{WordData, WordGroup};
+use crate::notification::NotificationData::{DbLoadError, DbSaveError};
+use crate::notification::{MaybeError, NotificationData};
 use rusqlite::{Connection, params};
 use std::collections::HashMap;
-use crate::data::entities::{WordData, WordGroup};
 
-pub fn add_word(word: &mut WordData, connection: &Connection) {
+pub fn add_word(word: &mut WordData, connection: &Connection) -> MaybeError {
     let index : u32 = connection
         .query_row(
             "INSERT INTO words (key, value, tags, more, group_id) VALUES (?1, ?2, ?3, ?4, ?5) RETURNING id",
@@ -10,17 +12,18 @@ pub fn add_word(word: &mut WordData, connection: &Connection) {
                 &word.key,
                 &word.value,
                 &word.tags,
-                serde_json::to_string(&word.additional).unwrap(),
+                serde_json::to_string(&word.additional).unwrap_or_default(),
                 &word.group_id,
             ),
             |row| row.get(0),
-        ).unwrap();
+        ).map_err(|_| DbSaveError)?;
 
     word.id = index.into();
+    Ok(())
 }
 
-pub fn add_words(words: &mut [WordData], connection: &mut Connection) {
+pub fn add_words(words: &mut [WordData], connection: &mut Connection) -> MaybeError {
-    let tx = connection.transaction().unwrap();
+    let tx = connection.transaction().map_err(|_| DbLoadError)?;
     let count = words.len();
 
     {
@@ -28,33 +31,35 @@ pub fn add_words(words: &mut [WordData], connection: &mut Connection) {
             .prepare(
                 "INSERT INTO words (key, value, tags, more, group_id) VALUES (?1, ?2, ?3, ?4, ?5)",
             )
-            .unwrap();
+            .expect("Failed to prepare statement");
 
         for word in words.iter() {
             stmt.execute(params![
                 word.key,
                 word.value,
                 word.tags,
-                serde_json::to_string(&word.additional).unwrap(),
+                serde_json::to_string(&word.additional).unwrap_or_default(),
                 word.group_id
             ])
-            .unwrap();
+            .map_err(|_| DbSaveError)?;
         }
     }
 
     let last_index: u32 = tx.last_insert_rowid() as u32;
-    tx.commit().unwrap();
+    tx.commit().map_err(|_| DbSaveError)?;
 
     let start_index = last_index - (count as u32) + 1;
 
     for (index, id) in (start_index..=last_index).enumerate() {
         words[index].id = id.into();
     }
+
+    Ok(())
 }
 
-pub fn update_word(word: &mut WordData, connection: &Connection) {
+pub fn update_word(word: &mut WordData, connection: &Connection) -> MaybeError {
     if !word.id.is_valid() {
-        add_word(word, connection);
+        Ok(add_word(word, connection)?)
     } else {
         connection
             .execute(
@@ -63,27 +68,29 @@ pub fn update_word(word: &mut WordData, connection: &Connection) {
                     &word.key,
                     &word.value,
                     &word.tags,
-                    serde_json::to_string(&word.additional).unwrap(),
+                    serde_json::to_string(&word.additional).map_err(|_| DbSaveError)?,
                     &word.id,
                 ),
             )
-            .unwrap();
+            .map_err(|_| DbSaveError)?;
+        Ok(())
     }
 }
 
-pub fn delete_word(word: &WordData, connection: &Connection) {
+pub fn delete_word(word: &WordData, connection: &Connection) -> MaybeError {
     if !word.id.is_valid() {
-        return;
+        return Err(DbSaveError);
     }
     connection
         .execute("DELETE FROM words WHERE id = ?1", (&word.id,))
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }
 
-pub fn load_words(connection: &Connection) -> Vec<WordData> {
+pub fn load_words(connection: &Connection) -> Result<Vec<WordData>, NotificationData> {
     let mut stmt = connection
         .prepare("SELECT id, key, value, tags, more, group_id FROM words")
-        .unwrap();
+        .expect("Failed to prepare statement");
     let word_iter = stmt
         .query_map([], |row| {
             let additional: String = row.get(4)?;
@@ -92,24 +99,25 @@ pub fn load_words(connection: &Connection) -> Vec<WordData> {
                 key: row.get(1)?,
                 value: row.get(2)?,
                 tags: row.get(3)?,
-                additional: serde_json::from_str::<HashMap<String, String>>(&additional).unwrap(),
+                additional: serde_json::from_str::<HashMap<String, String>>(&additional)
+                    .unwrap_or_default(),
                 group_id: row.get(5)?,
             })
         })
-        .unwrap();
+        .map_err(|_| DbLoadError)?;
 
-    let mut buffer = vec![];
+    let mut buffer = Vec::with_capacity(1024);
-    for word in word_iter {
+    word_iter
-        buffer.push(word.unwrap());
+        .filter_map(|res| res.ok())
-    }
+        .for_each(|i| buffer.push(i));
 
-    buffer
+    Ok(buffer)
 }
 
-pub fn load_word_groups(connection: &Connection) -> Vec<WordGroup> {
+pub fn load_word_groups(connection: &Connection) -> Result<Vec<WordGroup>, NotificationData> {
     let mut stmt = connection
         .prepare("SELECT id, name FROM word_group")
-        .unwrap();
+        .expect("Failed to prepare statement");
     let group_iter = stmt
         .query_map([], |row| {
             Ok(WordGroup {
@@ -117,46 +125,49 @@ pub fn load_word_groups(connection: &Connection) -> Vec<WordGroup> {
                 name: row.get(1)?,
             })
         })
-        .unwrap();
+        .map_err(|_| DbLoadError)?;
 
-    let mut buffer = vec![];
+    let mut buffer = Vec::with_capacity(8);
-    for group in group_iter {
+    group_iter
-        buffer.push(group.unwrap());
+        .filter_map(|res| res.ok())
-    }
+        .for_each(|i| buffer.push(i));
 
-    buffer
+    Ok(buffer)
 }
 
-pub fn add_group(group: &mut WordGroup, connection: &Connection) {
+pub fn add_group(group: &mut WordGroup, connection: &Connection) -> MaybeError {
     let index: u32 = connection
         .query_row(
             "INSERT INTO word_group (name) VALUES (?1) RETURNING id",
             (&group.name,),
             |row| row.get(0),
         )
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
 
     group.id = index.into();
+    Ok(())
 }
 
-pub fn update_group(group: &mut WordGroup, connection: &Connection) {
+pub fn update_group(group: &mut WordGroup, connection: &Connection) -> MaybeError {
     if !group.id.is_valid() {
-        add_group(group, connection);
+        Ok(add_group(group, connection)?)
     } else {
         connection
             .execute(
                 "UPDATE word_group SET name = ?1 WHERE id = ?2",
                 (&group.name, &group.id),
             )
-            .unwrap();
+            .map_err(|_| DbSaveError)?;
+        Ok(())
     }
 }
 
-pub fn delete_group(group: &WordGroup, connection: &Connection) {
+pub fn delete_group(group: &WordGroup, connection: &Connection) -> MaybeError {
     if !group.id.is_valid() {
-        return;
+        return Err(DbSaveError);
     }
     connection
         .execute("DELETE FROM word_group WHERE id = ?1", (&group.id,))
-        .unwrap();
+        .map_err(|_| DbSaveError)?;
+    Ok(())
 }

src/fs.rs

@@ -1,13 +1,13 @@
-use std::fs;
-use std::path::PathBuf;
 use crate::notification::NotificationData;
 use crate::notification::NotificationData::PermissionDenied;
+use std::fs;
+use std::path::PathBuf;
 
 pub fn app_data_dir() -> PathBuf {
-    let mut dir = dirs::data_dir().unwrap();
+    let mut dir = dirs::data_dir().expect("Unsupported OS");
     dir.push("jap_learn");
     if !dir.exists() {
-        fs::create_dir_all(dir.clone()).unwrap();
+        fs::create_dir_all(dir.clone()).expect("Unable to create directory");
     }
 
     dir

src/helpers.rs

@@ -0,0 +1,24 @@
+#[macro_export]
+macro_rules! push_error_task {
+    ($e:expr) => {
+        iced::Task::done(push_error!($e))
+    };
+}
+
+#[macro_export]
+macro_rules! push_error {
+    ($e:expr) => {
+        $crate::navigation::RootMessage::PushNotification(
+            $crate::notification::NotificationRequest::Error($e),
+        )
+    };
+}
+
+#[inline(always)]
+pub fn into_result<R, E>(option: Option<R>, error: E) -> Result<R, E> {
+    if let Some(r) = option {
+        Ok(r)
+    } else {
+        Err(error)
+    }
+}

src/main.rs

@@ -1,13 +1,14 @@
 #![windows_subsystem = "windows"]
-mod data_provider;
-pub mod notification;
 pub mod app;
-mod styling;
-mod pages;
-mod navigation;
-mod fs;
 mod core;
 mod data;
+mod data_provider;
+mod fs;
+pub mod helpers;
+mod navigation;
+pub mod notification;
+mod pages;
+mod styling;
 
 use crate::app::start;
 use mimalloc::MiMalloc;
@@ -15,7 +16,6 @@ use mimalloc::MiMalloc;
 #[global_allocator]
 static GLOBAL: MiMalloc = MiMalloc;
 
-
 fn main() -> iced::Result {
     env_logger::init();
     start()

src/navigation.rs

@@ -1,15 +1,16 @@
-use crate::app::{fill_state, AppState};
+use crate::app::{AppState, fill_state};
+use crate::data::Id;
 use crate::data_provider::history::get_history_of_set;
 use crate::data_provider::sqlite::{create_db, default_connection};
 use crate::data_provider::web_api::{
     get_local_version, get_web_version, load_data, set_local_version,
 };
 use crate::fs::*;
-use crate::message_navigation;
 use crate::navigation::Page::*;
 use crate::navigation::RootMessage::{
     DataLoaded, Keyboard, Notification, PushNotification, UpdateData,
 };
+use crate::notification::NotificationData::PermissionDenied;
 use crate::notification::{
     NotificationData, NotificationManager, NotificationMessage, NotificationRequest,
 };
@@ -29,6 +30,7 @@ use crate::pages::writing::{WritingMessage, WritingState};
 use crate::state_navigate_handle;
 use crate::state_update;
 use crate::view_navigation;
+use crate::{message_navigation, push_error, push_error_task};
 use chrono::NaiveDate;
 use hashbrown::HashMap;
 use iced::keyboard::Event;
@@ -40,7 +42,6 @@ use parking_lot::Mutex;
 use rusqlite::Connection;
 use std::sync::Arc;
 use std::time::Instant;
-use crate::data::Id;
 
 impl Default for ScreenState {
     fn default() -> Self {
@@ -77,7 +78,8 @@ pub enum RootMessage {
     None,
     UpdateData,
 }
-
+#[allow(clippy::enum_variant_names)]
+#[allow(clippy::large_enum_variant)]
 pub enum Page {
     Selector(SelectorState),
     Quiz(QuizState),
@@ -107,14 +109,17 @@ impl ScreenState {
         create_db();
         info!("Db created");
         let state = ScreenState::default();
-        let reading_additional_task = Task::perform(Self::load_additional_data(), |data| data);
+        let reading_additional_task = Task::perform(Self::load_additional_data(), |data| {
+            data.unwrap_or_else(|err| push_error!(err))
+        });
 
-        let final_task;
+        let mut final_task = reading_additional_task;
         let state_guard = state.app_state.lock();
-        if state_guard.sync_data.auto_web_fetch {
+        if state_guard.sync_data.auto_web_fetch
-            let key = state_guard.sync_data.key.clone().unwrap();
+            && let Some(key) = state_guard.sync_data.key.clone()
+        {
             final_task = Task::batch([
-                reading_additional_task,
+                final_task,
                 Task::perform(Self::load_web_backup(key), |result| match result {
                     Ok(update) => {
                         if update {
@@ -123,11 +128,9 @@ impl ScreenState {
                             RootMessage::None
                         }
                     }
-                    Err(err) => PushNotification(NotificationRequest::Warning(err)),
+                    Err(err) => push_error!(err),
                 }),
             ]);
-        } else {
-            final_task = reading_additional_task;
         }
 
         drop(state_guard);
@@ -135,23 +138,24 @@ impl ScreenState {
         (state, final_task)
     }
 
-    async fn load_additional_data() -> RootMessage {
+    async fn load_additional_data() -> Result<RootMessage, NotificationData> {
-        let directory = history_dir();
+        let directory = history_dir()?;
-        if let Ok(directory) = directory {
+
         let mut map = HashMap::new();
-            for file in directory.read_dir().unwrap().flatten() {
+        for file in directory
+            .read_dir()
+            .map_err(|_| PermissionDenied)?
+            .filter_map(Result::ok)
+        {
             let mut vec = vec![];
             let history_file_name = match file.file_name().into_string() {
                 Err(_) => continue,
                 Ok(v) => v,
             };
 
-                let id = history_file_name[4..history_file_name.len() - 12]
+            if let Ok(id) = history_file_name.split('_').collect::<Vec<_>>()[1].parse::<Id>()
-                    .parse::<Id>()
+                && let Ok(history) = get_history_of_set(id)
-                    .unwrap();
+            {
-
-                let history = get_history_of_set(id);
-                if let Ok(history) = history {
                 let by_date = history.chunk_by(|x, x1| {
                     x.timestamp.naive_local().date() == x1.timestamp.naive_local().date()
                 });
@@ -160,22 +164,20 @@ impl ScreenState {
                 }
                 map.insert(id, vec);
             } else {
-                    return PushNotification(NotificationRequest::Warning(history.err().unwrap()));
+                continue;
             }
         }
-            return DataLoaded(map);
+        Ok(DataLoaded(map))
-        }
-        PushNotification(NotificationRequest::Warning(directory.err().unwrap()))
     }
 
     async fn load_web_backup(string: String) -> Result<bool, NotificationData> {
-        let local = get_local_version().await;
+        let local = get_local_version().await?;
         let web = get_web_version(string.as_str()).await?;
         info!("{} {}", local, web);
         if web > local {
             info!("Web version is newer than local version");
             load_data(string, true).await?;
-            set_local_version(web).await;
+            set_local_version(web).await?;
         } else {
             return Ok(false);
         }
@@ -202,7 +204,9 @@ impl ScreenState {
             }
             let db_file = db_path();
             let temp_db_file = temp_db_path();
-            std::fs::rename(temp_db_file, &db_file).unwrap();
+            if std::fs::rename(temp_db_file, &db_file).is_err() {
+                return push_error_task!(PermissionDenied);
+            }
 
             state.connection = default_connection();
             fill_state(&mut state);
@@ -289,11 +293,13 @@ impl ScreenState {
     }
 
     fn handle_keyboard(&mut self, message: Event) -> Task<RootMessage> {
-        let page = self.stack.last_mut().unwrap();
+        if let Some(page) = self.stack.last_mut() {
-        match page {
+            return match page {
                 Repetition(page) => page.press(&message),
                 _ => Task::none(),
+            };
         }
+        Task::none()
     }
 }
 
@@ -305,7 +311,7 @@ pub struct AppSettings {
 #[macro_export]
 macro_rules! view_navigation {
     ($stack:expr, $($e:ident), *) => {
-        match &$stack.last().unwrap() {
+        match &$stack.last().expect("Unexpected stack state") {
             $(
             $e(s) => s.view().map(RootMessage::$e),
             )*
@@ -319,7 +325,7 @@ macro_rules! state_update {
         match $message {
             $(
             RootMessage::$e(msg) => {
-                if let $e(s) = $stack.last_mut().unwrap() {
+                if let $e(s) = $stack.last_mut().expect("Unexpected stack state") {
                     message_navigation!(msg, $stack, s)
                 }
                 else {
@@ -354,7 +360,7 @@ macro_rules! message_navigation {
 #[macro_export]
 macro_rules! state_navigate_handle {
     ($stack:expr, $($e:ident), *) => {
-        match $stack.last_mut().unwrap() {
+        match $stack.last_mut().expect("Unexpected stack state") {
             $(
             Page::$e(page) => {
                 page.navigated();

src/notification.rs

@@ -109,7 +109,9 @@ impl NotificationManager {
                 iced::widget::button("✕")
                     .on_press(NotificationMessage::Remove(*id))
                     .style(iced::widget::button::text)
-            ].align_y(Center).width(300)
+            ]
+            .align_y(Center)
+            .width(300)
             .padding(HALF_SPACING),
         );
         container
@@ -157,6 +159,15 @@ impl NotificationManager {
             NotificationData::WebApiUnavailable => {
                 text!("Не получается подключиться к Api")
             }
+            NotificationData::DbSaveError => {
+                text!("Не получается сохранить данные")
+            }
+            NotificationData::DbLoadError => {
+                text!("Не получается загрузить данные")
+            }
+            NotificationData::CompressError => {
+                text!("Ошибка сжатия или распаковки данных")
+            }
         }
         .width(Fill)
         .into()
@@ -170,7 +181,7 @@ pub enum NotificationRequest {
     Error(NotificationData),
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum NotificationData {
     PermissionDenied,
     DataLoaded,
@@ -179,4 +190,9 @@ pub enum NotificationData {
     OpenFileError,
     VoiceVoxUnavailable,
     WebApiUnavailable,
+    DbSaveError,
+    DbLoadError,
+    CompressError,
 }
+
+pub type MaybeError = Result<(), NotificationData>;

src/pages/dictionary.rs

@@ -1,12 +1,16 @@
+use crate::app::AppState;
 use crate::data::Id;
+use crate::data::entities::{WordData, WordGroup};
 use crate::data_provider::words::{delete_group, delete_word, update_group, update_word};
+use crate::navigation::Page::{Import, Word};
+use crate::navigation::{NavigatedPage, Page, RootMessage};
 use crate::pages::dictionary::DictionaryMessage::*;
 use crate::pages::dictionary_quiz::DictionaryQuizState;
 use crate::pages::import::ImportState;
-use crate::navigation::Page::{Import, Word};
-use crate::navigation::{NavigatedPage, Page, RootMessage};
-use crate::styling::*;
 use crate::pages::word::WordState;
+use crate::push_error;
+use crate::push_error_task;
+use crate::styling::*;
 use chrono::{DateTime, TimeDelta, Utc};
 use hashbrown::{HashMap, HashSet};
 use iced::alignment::Vertical::Center;
@@ -17,14 +21,12 @@ use iced::widget::text_input::default;
 use iced::widget::*;
 use iced::{Border, Color, Shadow, Task};
 use iced_core::Length::Fill;
+use log::info;
 use parking_lot::Mutex;
 use rand::random_range;
 use std::ops::Add;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
-use log::info;
-use crate::app::AppState;
-use crate::data::entities::{WordData, WordGroup};
 
 #[derive(Clone)]
 pub struct DictionaryState {
@@ -168,7 +170,9 @@ impl NavigatedPage<DictionaryMessage> for DictionaryState {
                 let word = dict.remove(i);
                 self.include_map.remove(i);
                 self.auto_save_queue.remove(&i);
-                delete_word(&word, &state.connection)
+                if let Err(err) = delete_word(&word, &state.connection) {
+                    return push_error_task!(err);
+                }
             }
             Include(i, b) => self.include_map[i] = b,
             IncludeTag(t, v) => {
@@ -190,7 +194,7 @@ impl NavigatedPage<DictionaryMessage> for DictionaryState {
                 self.search = s;
             }
             SetTyping(b) => self.no_typing = b,
-            SubmitWord(i) => self.save_word(i),
+            SubmitWord(i) => return self.save_word(i),
             Back => {}
             Test => {}
             CreateGroup => {
@@ -213,7 +217,10 @@ impl NavigatedPage<DictionaryMessage> for DictionaryState {
                 let connection = &state.connection;
                 let mut group = state.word_groups[self.selected_group_index].clone();
 
-                update_group(&mut group, connection);
+                if let Err(err) = update_group(&mut group, connection) {
+                    return push_error_task!(err);
+                }
+
                 state.word_groups[self.selected_group_index] = group;
             }
             SelectGroup(i) => {
@@ -236,7 +243,10 @@ impl NavigatedPage<DictionaryMessage> for DictionaryState {
                         let remove_group_id = group.id;
                         let connection = &state.connection;
 
-                        delete_group(group, connection);
+                        if let Err(err) = delete_group(group, connection) {
+                            return push_error_task!(err);
+                        }
+
                         state.word_groups.remove(self.selected_group_index);
                         state
                             .dictionary
@@ -257,7 +267,8 @@ impl NavigatedPage<DictionaryMessage> for DictionaryState {
                 }
                 if self.auto_save_queue[&word_index] <= now {
                     self.auto_save_queue.remove(&word_index);
-                    self.save_word(word_index);
+
+                    return self.save_word(word_index);
                 }
             }
             ToImport => {}
@@ -309,13 +320,17 @@ impl DictionaryState {
         result
     }
 
-    fn save_word(&mut self, i: usize) {
+    fn save_word(&mut self, i: usize) -> Task<RootMessage> {
         let state = &mut self.state.lock();
         let connection = &state.connection;
         let word = &mut state.dictionary[i].clone();
 
-        update_word(word, connection);
+        if let Err(err) = update_word(word, connection) {
+            return push_error_task!(err);
+        }
+
         state.dictionary[i] = word.clone();
+        Task::none()
     }
 
     fn launch_auto_save_offset(&mut self, index: usize) -> Task<RootMessage> {

src/pages/dictionary_quiz.rs

@@ -1,8 +1,9 @@
+use crate::data::entities::WordData;
+use crate::navigation::Page::PreviousPage;
 use crate::navigation::RootMessage;
+use crate::navigation::*;
 use crate::pages::dictionary::split_with_coma;
 use crate::pages::dictionary_quiz::DictionaryQuizMessage::*;
-use crate::navigation::Page::PreviousPage;
-use crate::navigation::*;
 use crate::pages::quiz::Score;
 use crate::styling::*;
 use iced::Background::Color;
@@ -11,7 +12,6 @@ use iced::widget::container::Style;
 use iced::widget::{Row, button, container, row, space, text, text_input};
 use iced::{Border, Element, Fill, Task, Theme, alignment};
 use rand::prelude::SliceRandom;
-use crate::data::entities::WordData;
 
 #[derive(Debug, Clone)]
 pub struct DictionaryQuizState {
@@ -147,7 +147,8 @@ impl DictionaryQuizState {
             self.score.total += 1;
         }
         if self.answer.to_lowercase() == self.correct.to_lowercase()
-            || split_with_coma(self.correct.to_lowercase().as_str()).contains(&self.answer.to_lowercase())
+            || split_with_coma(self.correct.to_lowercase().as_str())
+                .contains(&self.answer.to_lowercase())
         {
             if !self.is_help {
                 self.score.correct += 1;

src/pages/history.rs

@@ -1,6 +1,10 @@
-use crate::data_provider::history::{get_history_of_set};
+use crate::app::AppState;
+use crate::data::INVALID_ID;
+use crate::data::entities::{HistoryItem, WordData};
+use crate::data_provider::history::get_history_of_set;
 use crate::navigation::*;
 use crate::styling::*;
+use HistoryMessage::Back;
 use chrono::Local;
 use iced::alignment::Horizontal::Center;
 use iced::widget::space::horizontal;
@@ -8,10 +12,6 @@ use iced::widget::*;
 use iced::{Element, Fill, FillPortion, Task};
 use parking_lot::Mutex;
 use std::sync::Arc;
-use HistoryMessage::Back;
-use crate::app::AppState;
-use crate::data::entities::{HistoryItem, WordData};
-use crate::data::INVALID_ID;
 
 #[derive(Clone)]
 pub struct HistoryState {

src/pages/import.rs

@@ -1,10 +1,13 @@
+use crate::app::AppState;
+use crate::data::entities::{WordData, WordGroup};
 use crate::data_provider::import::{ImportData, ImportGroup, get_words_of_group, load_groups};
 use crate::data_provider::words::{add_group, add_words};
-use crate::pages::import::ImportMessage::*;
+use crate::fs::*;
-use crate::data::entities::{WordData, WordGroup};
 use crate::navigation::{NavigatedPage, Page, RootMessage};
 use crate::notification::NotificationData::OpenFileError;
-use crate::notification::{NotificationData, NotificationRequest};
+use crate::notification::{MaybeError, NotificationData};
+use crate::pages::import::ImportMessage::*;
+use crate::push_error;
 use crate::styling::*;
 use iced::widget::button::danger;
 use iced::widget::container::success;
@@ -16,6 +19,7 @@ use iced::{Element, Task};
 use iced_core::Alignment::Center;
 use iced_core::Length::Fill;
 use iced_core::Padding;
+use log::info;
 use parking_lot::Mutex;
 use rfd::AsyncFileDialog;
 use rusqlite::Connection;
@@ -23,11 +27,8 @@ use std::fs::{File, OpenOptions};
 use std::io::BufReader;
 use std::path::PathBuf;
 use std::sync::Arc;
-use log::info;
 use tokio::task::spawn_blocking;
 use zip::ZipArchive;
-use crate::app::AppState;
-use crate::fs::*;
 
 const DEFAULT_FIELDS: [&str; 6] = ["key", "value", "tags", "reading", "context", "description"];
 
@@ -367,12 +368,12 @@ impl ImportState {
             },
             |result: Result<ImportData, NotificationData>| match result {
                 Ok(import) => RootMessage::Import(UpdateImport(import)),
-                Err(err) => RootMessage::PushNotification(NotificationRequest::Error(err)),
+                Err(err) => push_error!(err),
             },
         )
     }
 
-    fn extract_import_file(path: PathBuf) -> Result<(), NotificationData> {
+    fn extract_import_file(path: PathBuf) -> MaybeError {
         let file = File::open(path).map_err(|_| OpenFileError)?;
         let reader = BufReader::new(file);
         let mut archive = ZipArchive::new(reader).map_err(|_| OpenFileError)?;
@@ -432,7 +433,8 @@ impl ImportState {
             async move {
                 spawn_blocking(move || {
                     let temp_file_path = temp_import_path();
-                    let connection = Connection::open(&temp_file_path).map_err(|_| OpenFileError)?;
+                    let connection =
+                        Connection::open(&temp_file_path).map_err(|_| OpenFileError)?;
                     let import_list = get_words_of_group(&connection, group.id)?;
                     let mut words_list = Vec::with_capacity(import_list.len());
 
@@ -443,7 +445,7 @@ impl ImportState {
                     };
                     {
                         let state = state.lock();
-                        add_group(&mut group_entity, &state.connection);
+                        add_group(&mut group_entity, &state.connection)?;
                     }
 
                     let group_id = group_entity.id;
@@ -483,7 +485,7 @@ impl ImportState {
                     let mut index = 0;
                     let total_len = words_list.len() as f32 / 1024.0;
                     for word in &mut words_list.chunks_mut(1024) {
-                        add_words(word, connection);
+                        add_words(word, connection)?;
                         index += 1;
                         let mut progress = progress.lock();
                         *progress = (index as f32 / total_len).min(1.0);
@@ -499,8 +501,8 @@ impl ImportState {
             },
             |r: Result<(), NotificationData>| match r {
                 Ok(_) => RootMessage::Import(ImportFinished),
-                Err(err) => RootMessage::PushNotification(NotificationRequest::Error(err))
+                Err(err) => push_error!(err),
-            }
+            },
         )
     }
 

src/pages/quiz.rs

@@ -1,4 +1,5 @@
-
+use crate::app::USER_FONT;
+use crate::core::kana_set::KanaSet;
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
 use crate::pages::quiz::QuizMessage::*;
@@ -6,8 +7,6 @@ use crate::styling::*;
 use iced::widget::*;
 use iced::{Element, Fill, Task, alignment};
 use rand::seq::SliceRandom;
-use crate::app::USER_FONT;
-use crate::core::kana_set::KanaSet;
 
 #[derive(Clone, Debug)]
 pub struct QuizState {

src/pages/repetition.rs

@@ -1,19 +1,20 @@
 use crate::app::AppState;
 use crate::core::deck::DeckData;
 use crate::core::srs::WordOpenMode;
-use crate::data::entities::{CardStatistics, DeckSettings, WordData};
 use crate::data::Id;
+use crate::data::entities::{CardStatistics, DeckSettings, WordData};
 use crate::data_provider::voice::get_voice;
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{KeyPressedPage, NavigatedPage, Page, RootMessage};
-use crate::notification::{NotificationData, NotificationRequest};
+use crate::notification::{MaybeError, NotificationData};
 use crate::styling::*;
+use crate::{push_error, push_error_task};
 use chrono::Local;
 use iced::alignment::Horizontal::Center;
 use iced::keyboard::key::Physical::Code;
 use iced::widget::text::Style;
-use iced::widget::{button, column, container, row, rule, space, text, tooltip, Column};
+use iced::widget::{Column, button, column, container, row, rule, space, text, tooltip};
-use iced::{alignment, keyboard, Element, Fill, Task, Theme};
+use iced::{Element, Fill, Task, Theme, alignment, keyboard};
 use parking_lot::Mutex;
 use rodio::MixerDeviceSink;
 use std::collections::HashSet;
@@ -57,7 +58,7 @@ impl NavigatedPage<RepetitionMessage> for RepetitionState {
                 if self.settings.require_speech() {
                     return Task::perform(play_sound(self.sink.clone(), value), |r| match r {
                         Ok(_) => RootMessage::Repetition(RepetitionMessage::PlayFinished),
-                        Err(err) => RootMessage::PushNotification(NotificationRequest::Error(err)),
+                        Err(err) => push_error!(err),
                     });
                 }
             }
@@ -101,8 +102,11 @@ impl NavigatedPage<RepetitionMessage> for RepetitionState {
 }
 
 impl RepetitionState {
-    pub(crate) fn new(set: DeckSettings, state: Arc<Mutex<AppState>>) -> RepetitionState {
+    pub(crate) fn new(
-        let mut card_set = DeckData::new(&set, state.clone());
+        set: DeckSettings,
+        state: Arc<Mutex<AppState>>,
+    ) -> Result<RepetitionState, NotificationData> {
+        let mut card_set = DeckData::new(&set, state.clone())?;
         let (word, stat) = card_set.next();
 
         let sink_handle = if set.forward.contains("speech") || set.backward.contains("speech") {
@@ -111,7 +115,7 @@ impl RepetitionState {
             None
         };
 
-        RepetitionState {
+        Ok(RepetitionState {
             state,
             settings: set,
             set: card_set,
@@ -121,7 +125,7 @@ impl RepetitionState {
             can_play: true,
             sink: Arc::new(sink_handle),
             opened: HashSet::new(),
-        }
+        })
     }
 }
 
@@ -140,7 +144,10 @@ impl RepetitionState {
             return Task::none();
         }
 
-        self.set.open(mode);
+        if let Err(err) = self.set.open(mode) {
+            return push_error_task!(err);
+        }
+
         self.open = false;
         self.opened.insert(self.current_word.id);
         let next = self.set.next();
@@ -152,7 +159,7 @@ impl RepetitionState {
             let task = play_sound(sink, self.current_word.key.clone());
             return Task::perform(task, |r| match r {
                 Ok(_) => RootMessage::Repetition(RepetitionMessage::PlayFinished),
-                Err(err) => RootMessage::PushNotification(NotificationRequest::Error(err)),
+                Err(err) => push_error!(err),
             });
         }
         self.increment_counter();
@@ -327,10 +334,7 @@ pub enum RepetitionMessage {
     PlayFinished,
 }
 
-async fn play_sound(
+async fn play_sound(sink: Arc<Option<MixerDeviceSink>>, text: String) -> MaybeError {
-    sink: Arc<Option<MixerDeviceSink>>,
-    text: String,
-) -> Result<(), NotificationData> {
     let data = get_voice(text.as_str()).await?;
     spawn_blocking(move || {
         if let Some(sink) = sink.as_ref()
@@ -340,6 +344,6 @@ async fn play_sound(
         }
     })
     .await
-    .unwrap();
+    .expect("Playing sound failed");
     Ok(())
 }

src/pages/repetition_settings.rs

@@ -1,10 +1,13 @@
-
+use crate::app::AppState;
+use crate::data::entities::DeckSettings;
 use crate::data_provider::card_sets::{delete_set, update_deck};
 use crate::data_provider::card_stats::{delete_stats, load_stats_of_deck};
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
+use crate::notification::MaybeError;
 use crate::pages::repetition_settings::RepetitionSettingsMessage::*;
 use crate::styling::*;
+use crate::{push_error, push_error_task};
 use iced::widget::button::danger;
 use iced::widget::text_input::Catalog;
 use iced::widget::{button, column, row, scrollable, space, text, text_input};
@@ -14,8 +17,6 @@ use iced_core::{Padding, Theme, color};
 use parking_lot::Mutex;
 use std::sync::Arc;
 use std::time::Duration;
-use crate::app::AppState;
-use crate::data::entities::DeckSettings;
 
 pub struct RepetitionSettingsState {
     set: DeckSettings,
@@ -61,9 +62,13 @@ impl NavigatedPage<RepetitionSettingsMessage> for RepetitionSettingsState {
             Back => {}
             Save => {
                 let mut state = self.state.lock();
-                update_deck(&mut self.set, &state.connection);
+                if let Err(e) = update_deck(&mut self.set, &state.connection) {
-                if self.filter_changed {
+                    return push_error_task!(e);
-                    update_deck_stats(&self.set, &state);
+                }
+                if self.filter_changed
+                    && let Err(e) = update_deck_stats(&self.set, &state)
+                {
+                    return push_error_task!(e);
                 }
                 state.decks[self.index] = self.set.clone();
             }
@@ -95,7 +100,10 @@ impl NavigatedPage<RepetitionSettingsMessage> for RepetitionSettingsState {
                     });
                 }
                 let mut state = self.state.lock();
-                delete_set(&self.set, &state.connection);
+                if let Err(e) = delete_set(&self.set, &state.connection) {
+                    return push_error_task!(e);
+                }
+
                 state.decks.remove(self.index);
                 return Task::done(RootMessage::RepetitionSettings(Back));
             }
@@ -171,8 +179,8 @@ impl NavigatedPage<RepetitionSettingsMessage> for RepetitionSettingsState {
     }
 }
 
-fn update_deck_stats(deck: &DeckSettings, state: &AppState) {
+fn update_deck_stats(deck: &DeckSettings, state: &AppState) -> MaybeError {
-    let mut db_stats = load_stats_of_deck(deck, &state.connection);
+    let mut db_stats = load_stats_of_deck(deck, &state.connection).expect("Wrong db operation");
     let filtered_words = deck.get_word_list(state);
     filtered_words.iter().for_each(|word| {
         let word_id = state.dictionary[*word].id;
@@ -181,7 +189,8 @@ fn update_deck_stats(deck: &DeckSettings, state: &AppState) {
         }
     });
 
-    delete_stats(db_stats.as_slice(), &state.connection);
+    delete_stats(db_stats.as_slice(), &state.connection)?;
+    Ok(())
 }
 
 impl RepetitionSettingsState {

src/pages/repetitions.rs

@@ -6,10 +6,13 @@ use crate::data_provider::card_sets::update_deck;
 use crate::data_provider::card_stats::{add_stat_list, load_stats_of_deck};
 use crate::navigation::Page::{History, PreviousPage, Repetition, RepetitionSettings};
 use crate::navigation::{NavigatedPage, Page, RootMessage};
+use crate::notification::{MaybeError, NotificationRequest};
 use crate::pages::history::HistoryState;
 use crate::pages::repetition::RepetitionState;
 use crate::pages::repetition_settings::RepetitionSettingsState;
 use crate::pages::repetitions::RepetitionsMessage::*;
+use crate::push_error;
+use crate::push_error_task;
 use crate::styling::*;
 use chrono::{Days, Local, Utc};
 use hashbrown::{HashMap, HashSet};
@@ -50,7 +53,9 @@ impl NavigatedPage<RepetitionsMessage> for RepetitionsState {
 
             let selected_set = self.selected_deck_mut().unwrap();
             if selected_set.append_mode == AppendMode::Full {
-                Self::append_all_words(&mut clone.lock(), selected_set);
+                if let Err(_err) = Self::append_all_words(&mut clone.lock(), selected_set) {
+                    return None;
+                }
                 selected_set.existing_words_indices = selected_set.available_words_indices.clone();
             } else {
                 if selected_set.available_words_indices.is_empty()
@@ -60,10 +65,13 @@ impl NavigatedPage<RepetitionsMessage> for RepetitionsState {
                 }
             }
 
-            Some(Repetition(RepetitionState::new(
+            if let Ok(repetition_state) =
-                selected_set.general_settings.clone(),
+                RepetitionState::new(selected_set.general_settings.clone(), clone)
-                clone,
+            {
-            )))
+                return Some(Repetition(repetition_state));
+            }
+
+            None
         } else if let GoToSettings = message {
             Some(RepetitionSettings(RepetitionSettingsState::new(
                 self.selected_deck().unwrap().index.unwrap(),
@@ -82,10 +90,9 @@ impl NavigatedPage<RepetitionsMessage> for RepetitionsState {
                     self.decks.remove(index);
                     self.clear_selection();
                 } else {
-                    self.decks[index].general_settings =
+                    self.decks[index].general_settings = state.decks[index].clone();
-                        state.decks[index].clone();
                     drop(state);
-                    self.fill_deck_word_indices();
+                    let _ = self.fill_deck_word_indices();
                 }
             } else {
                 drop(state);
@@ -138,15 +145,21 @@ impl NavigatedPage<RepetitionsMessage> for RepetitionsState {
             SelectSet(index) => {
                 self.select_deck(index);
                 let deck = self.selected_deck().unwrap();
-                if !deck.indices_ready {
+                if !deck.indices_ready
-                    self.fill_deck_word_indices();
+                    && let Err(err) = self.fill_deck_word_indices()
+                {
+                    return push_error_task!(err);
                 }
             }
             Save => {
                 let mut deck = self.selected_deck().unwrap().clone();
                 let mut state = self.state.lock();
                 {
-                    update_deck(&mut deck.general_settings, &state.connection);
+                    if let Err(e) = update_deck(&mut deck.general_settings, &state.connection) {
+                        return Task::done(RootMessage::PushNotification(
+                            NotificationRequest::Error(e),
+                        ));
+                    }
                     if let Some(index) = deck.index {
                         state.decks[index] = deck.general_settings.clone();
                     } else {
@@ -209,7 +222,11 @@ impl NavigatedPage<RepetitionsMessage> for RepetitionsState {
 
                 let deck = self.selected_deck().unwrap();
                 let mut state = self.state.lock();
-                Self::append_words(&mut state, &deck.general_settings, adding.into_iter());
+                if let Err(err) =
+                    Self::append_words(&mut state, &deck.general_settings, adding.into_iter())
+                {
+                    return push_error_task!(err);
+                }
             }
         }
         Task::none()
@@ -433,7 +450,7 @@ impl RepetitionsState {
 
                     let date = (*now)
                         .checked_sub_days(Days::new(30 * 7 - i * 7 - j - 1))
-                        .unwrap();
+                        .unwrap_or_default();
 
                     column = column.push(tooltip(
                         iced::widget::container(space().height(15).width(15)).style(
@@ -545,7 +562,7 @@ impl RepetitionsState {
 }
 
 impl RepetitionsState {
-    fn append_all_words(state: &mut AppState, deck: &DeckViewData) {
+    fn append_all_words(state: &mut AppState, deck: &DeckViewData) -> MaybeError {
         let existing = &deck.existing_words_indices;
         let mut created_set = HashSet::with_capacity(existing.len());
         existing.iter().for_each(|c| {
@@ -556,13 +573,14 @@ impl RepetitionsState {
             .iter()
             .filter(|i| !created_set.contains(i))
             .cloned();
-        Self::append_words(state, deck, required);
+        Self::append_words(state, deck, required)?;
+        Ok(())
     }
     fn append_words(
         state: &mut AppState,
         deck: &DeckSettings,
         indices: impl Iterator<Item = usize>,
-    ) {
+    ) -> MaybeError {
         let words = &state.dictionary;
         let stats = &mut indices
             .map(|i| {
@@ -578,8 +596,9 @@ impl RepetitionsState {
             .collect::<Vec<_>>();
 
         if !stats.is_empty() {
-            add_stat_list(stats, &mut state.connection);
+            add_stat_list(stats, &mut state.connection)?;
         }
+        Ok(())
     }
 
     fn select_deck(&mut self, index: usize) {
@@ -599,10 +618,10 @@ impl RepetitionsState {
         self.selected_deck_index = None;
     }
 
-    fn fill_deck_word_indices(&mut self) {
+    fn fill_deck_word_indices(&mut self) -> MaybeError {
         let state = &self.state.lock();
         let mut deck = self.selected_deck().unwrap().clone();
-        let added: Vec<_> = load_stats_of_deck(&deck, &state.connection)
+        let added: Vec<_> = load_stats_of_deck(&deck, &state.connection)?
             .iter()
             .map(|c| self.word_id_index_map[&c.word_id])
             .collect();
@@ -610,6 +629,7 @@ impl RepetitionsState {
         deck.existing_words_indices = added;
         deck.available_words_indices = total;
         self.decks[self.selected_deck_index.unwrap()] = deck;
+        Ok(())
     }
 }
 #[derive(Clone)]

src/pages/selector.rs

@@ -1,12 +1,15 @@
-use crate::pages::dictionary::DictionaryState;
+use crate::app::AppState;
+use crate::core::kana_set::{KanaSet, KanaType};
 use crate::navigation::Page::*;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
+use crate::pages::dictionary::DictionaryState;
+use crate::pages::quiz::QuizState;
 use crate::pages::randomizer::RandomizerState;
 use crate::pages::repetitions::RepetitionsState;
 use crate::pages::selector::SelectorMessage::ChangeMode;
-use crate::styling::*;
 use crate::pages::sync::SyncState;
 use crate::pages::writing::WritingState;
+use crate::styling::*;
 use iced::widget::button::{Status, Style};
 use iced::widget::*;
 use iced::{Element, Task, alignment};
@@ -15,9 +18,6 @@ use iced_core::Background;
 use iced_core::Color;
 use parking_lot::Mutex;
 use std::sync::Arc;
-use crate::app::AppState;
-use crate::core::kana_set::{KanaSet, KanaType};
-use crate::pages::quiz::QuizState;
 
 pub struct SelectorState {
     pub set: KanaSet,

src/pages/sync.rs

@@ -1,19 +1,20 @@
+use crate::app::{AppState, fill_state};
 use crate::data_provider::settings::{delete_settings, set_setting};
 use crate::data_provider::web_api::*;
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
-use crate::styling::*;
+use crate::notification::{NotificationData, NotificationRequest};
 use crate::pages::sync::SyncMessage::*;
+use crate::styling::*;
+use crate::{push_error, push_error_task};
 use iced::widget::button::danger;
 use iced::widget::container::rounded_box;
 use iced::widget::{button, column, container, progress_bar, row, space, text, toggler};
 use iced::{Center, Element, Fill, Font, Length, Task};
+use log::error;
 use parking_lot::Mutex;
 use std::sync::Arc;
 use std::time::Duration;
-use log::error;
-use crate::app::{fill_state, AppState};
-use crate::notification::{NotificationRequest, NotificationData};
 
 #[derive(Clone)]
 pub enum SyncMessage {
@@ -61,11 +62,9 @@ impl NavigatedPage<SyncMessage> for SyncState {
                     .map(|_val: String| RootMessage::Sync(KeyCopied));
             }
             InitSync => {
-                return Task::perform(first_sync(), |id| {
+                return Task::perform(first_sync(), |id| match id {
-                    match id {
                     Ok(id) => RootMessage::Sync(IdReceived(id)),
-                        Err(err) => RootMessage::PushNotification(NotificationRequest::Error(err))
+                    Err(err) => push_error!(err),
-                    }
                 });
             }
             GetKey => {
@@ -79,7 +78,9 @@ impl NavigatedPage<SyncMessage> for SyncState {
                 }
                 let mut state = self.state.lock();
                 state.sync_data.key = Some(new_id.clone());
-                set_setting("SYNC_KEY".to_string(), new_id, &state.connection);
+                if let Err(err) = set_setting("SYNC_KEY".to_string(), new_id, &state.connection) {
+                    return push_error_task!(err);
+                }
             }
             Send => {
                 self.prepare_to_db_interaction();
@@ -130,24 +131,35 @@ impl NavigatedPage<SyncMessage> for SyncState {
                 state.decks = updated_state.decks;
                 state.dictionary = updated_state.dictionary;
                 state.word_groups = updated_state.word_groups;
-                return Task::done(RootMessage::PushNotification(NotificationRequest::Info(NotificationData::DataLoaded)))
+                return Task::done(RootMessage::PushNotification(NotificationRequest::Info(
+                    NotificationData::DataLoaded,
+                )));
             }
             Disable => {}
             DisableSync => {
                 let mut state = self.state.lock();
                 state.sync_data.key = None;
-                delete_settings("SYNC_KEY".to_string(), &state.connection);
+                let save_result = || {
-                delete_settings("AUTO_WEB_FETCH".to_string(), &state.connection);
+                    delete_settings("SYNC_KEY".to_string(), &state.connection)?;
+                    delete_settings("AUTO_WEB_FETCH".to_string(), &state.connection)?;
+                    Ok::<(), NotificationData>(())
+                };
+
+                if let Err(error) = save_result() {
+                    return push_error_task!(error);
+                }
             }
             SwitchAutoSync => {
                 self.auto_fetch = !self.auto_fetch;
                 let mut state = self.state.lock();
                 state.sync_data.auto_web_fetch = self.auto_fetch;
-                set_setting(
+                if let Err(err) = set_setting(
                     "AUTO_WEB_FETCH".to_string(),
                     self.auto_fetch.to_string(),
                     &state.connection,
-                );
+                ) {
+                    return push_error_task!(err);
+                }
             }
         }
         Task::none()

src/pages/word.rs

@@ -1,15 +1,17 @@
-use crate::data_provider::words::{delete_word, update_word};
+use crate::app::AppState;
 use crate::data::entities::WordData;
+use crate::data_provider::words::{delete_word, update_word};
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
-use crate::styling::*;
 use crate::pages::word::WordMessage::*;
+use crate::push_error;
+use crate::push_error_task;
+use crate::styling::*;
 use iced::widget::button::danger;
 use iced::widget::{button, column, row, rule, scrollable, text, text_input};
 use iced::{Element, Fill, Task};
 use parking_lot::Mutex;
 use std::sync::Arc;
-use crate::app::AppState;
 
 #[derive(Clone)]
 pub struct WordState {
@@ -34,13 +36,18 @@ impl NavigatedPage<WordMessage> for WordState {
             Save => {
                 let mut state = self.state.lock();
                 state.dictionary[self.index] = self.word.clone();
-                update_word(&mut self.word, &state.connection);
+
+                if let Err(err) = update_word(&mut self.word, &state.connection) {
+                    return push_error_task!(err);
+                }
                 return Task::done(RootMessage::Word(Back));
             }
             Delete => {
                 let mut state = self.state.lock();
                 state.dictionary.remove(self.index);
-                delete_word(&self.word, &state.connection);
+                if let Err(err) = delete_word(&self.word, &state.connection) {
+                    return push_error_task!(err);
+                }
                 return Task::done(RootMessage::Word(Back));
             }
             SetTags(n) => self.word.tags = n,

src/pages/writing.rs

@@ -1,11 +1,10 @@
-
+use crate::core::kana_set::KanaSet;
 use crate::navigation::Page::PreviousPage;
 use crate::navigation::{NavigatedPage, Page, RootMessage};
 use crate::styling::*;
 use iced::widget::*;
 use iced::{Element, Fill, Task, alignment};
 use rand::seq::SliceRandom;
-use crate::core::kana_set::KanaSet;
 
 #[derive(Clone, Debug)]
 pub struct WritingState {