import { worker } from "./main";

let requestId = 0;

type WorkerRequest = {
    resolve: (data: any) => void;
    reject: (error: Error) => void;
};
let initPromise: Promise<void> | null = null;
const pending = new Map<number, WorkerRequest>();

export function initWorker(): Promise<void> {
    if (initPromise) return initPromise;

    initPromise = new Promise((resolve, reject) => {
        worker.onmessage = (e: MessageEvent) => {
            console.log("Handling worker output");
            const msg = e.data;

            if (msg.type === 'ready') {
                // Готов — запрос init уже обработан
                return;
            }

                const pendingReq = pending.get(msg.id);
                if (!pendingReq) return;
                pending.delete(msg.id);

                if (msg.type == "success") {
                    pendingReq.resolve(msg.data);
                } else {
                    console.log(msg)
                    pendingReq.reject(new Error(msg.error || 'Неизвестная ошибка Worker'));
                }
        };

        worker.onerror = (err) => {
            console.error('[SQLite Worker] Ошибка:', err);
            reject(new Error('Ошибка Worker'));
        };

        // Отправляем init
        const id = ++requestId;
        pending.set(id, { resolve, reject });
        worker.postMessage({ type: 'start', id });
    });

    return initPromise;
}

function sendToWorker(type: string, payload?: any): Promise<any> {
    return new Promise((resolve, reject) => {
        if (!worker) {
            reject(new Error('Worker не создан'));
            return;
        }

        const id = ++requestId;
        pending.set(id, { resolve, reject });

        worker.postMessage({ type, id, ...payload });
    });
}

export async function query(sql: string, params?: any[]): Promise<any[]> {
    const result = await sendToWorker('query', { sql, params });
    return result;
}

export async function command(sql: string, params?: any[]): Promise<void> {
    await sendToWorker('command', { sql, params });
}

export async function closeDb(): Promise<void> {
    await sendToWorker('close');
    worker.terminate();
}