import type { IpcMainInvokeEvent } from 'electron';
import Store from 'electron-store';

// Electron store instance for session management
const store = new Store({
    encryptionKey: 'eritors-scribe-secure-key'
});

// ============================================================
// SESSION MANAGEMENT - Retrieve userId and lang from store
// ============================================================

/**
 * Get userId from electron-store
 * Set during login via 'login-success' event
 */
function getUserIdFromSession(): string | null {
    return store.get('userId', null) as string | null;
}

/**
 * Get lang from electron-store
 * Set via 'set-lang' handler, defaults to 'fr'
 */
function getLangFromSession(): 'fr' | 'en' {
    return store.get('userLang', 'fr') as 'fr' | 'en';
}

// ============================================================
// LEGACY HANDLERS - Manual userId injection, lang must be passed
// Keep these for backward compatibility
// Updated to support Promises
// ============================================================

export function createDbHandler<TReturn>(
    handler: (userId: string) => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent): Promise<TReturn> {
        const userId = getUserIdFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

export function createDbHandler1<T1, TReturn>(
    handler: (userId: string, arg1: T1) => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1): Promise<TReturn> {
        const userId = getUserIdFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

export function createDbHandler2<T1, T2, TReturn>(
    handler: (userId: string, arg1: T1, arg2: T2) => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1, arg2: T2) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1, arg2: T2): Promise<TReturn> {
        const userId = getUserIdFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1, arg2);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

export function createDbHandler3<T1, T2, T3, TReturn>(
    handler: (userId: string, arg1: T1, arg2: T2, arg3: T3) => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1, arg2: T2, arg3: T3) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1, arg2: T2, arg3: T3): Promise<TReturn> {
        const userId = getUserIdFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1, arg2, arg3);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

// ============================================================
// AUTO HANDLERS - Automatically inject userId AND lang
// Use these for new handlers - no need to pass lang from frontend
// ============================================================

/**
 * Auto-handler with 0 parameters
 * Automatically injects: userId, lang
 *
 * @example
 * ipcMain.handle('db:user:get', createAutoHandler<UserProps>(
 *     function(userId: string, lang: 'fr' | 'en') {
 *         return User.getUser(userId, lang);
 *     }
 * ));
 *
 * // Frontend call (no params needed):
 * const user = await window.electron.invoke('db:user:get');
 */
export function createAutoHandler<TReturn>(
    handler: (userId: string, lang: 'fr' | 'en') => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent): Promise<TReturn> {
        const userId = getUserIdFromSession();
        const lang = getLangFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, lang);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

/**
 * Auto-handler with 1 parameter
 * Automatically injects: userId, lang
 *
 * @example
 * ipcMain.handle('db:book:get', createAutoHandler1<string, BookProps>(
 *     function(userId: string, bookId: string, lang: 'fr' | 'en') {
 *         return Book.getBook(bookId, userId, lang);
 *     }
 * ));
 *
 * // Frontend call (only bookId needed):
 * const book = await window.electron.invoke('db:book:get', bookId);
 */
export function createAutoHandler1<T1, TReturn>(
    handler: (userId: string, arg1: T1, lang: 'fr' | 'en') => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1): Promise<TReturn> {
        const userId = getUserIdFromSession();
        const lang = getLangFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1, lang);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

/**
 * Auto-handler with 2 parameters
 * Automatically injects: userId, lang
 *
 * @example
 * ipcMain.handle('db:book:create', createAutoHandler1<CreateBookData, string>(
 *     function(userId: string, data: CreateBookData, lang: 'fr' | 'en') {
 *         return Book.addBook(null, userId, data.title, ..., lang);
 *     }
 * ));
 *
 * // Frontend call (only data needed):
 * const bookId = await window.electron.invoke('db:book:create', bookData);
 */
export function createAutoHandler2<T1, T2, TReturn>(
    handler: (userId: string, arg1: T1, arg2: T2, lang: 'fr' | 'en') => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1, arg2: T2) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1, arg2: T2): Promise<TReturn> {
        const userId = getUserIdFromSession();
        const lang = getLangFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1, arg2, lang);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

/**
 * Auto-handler with 3 parameters
 * Automatically injects: userId, lang
 *
 * @example
 * ipcMain.handle('db:book:cover:update', createAutoHandler2<string, string, boolean>(
 *     function(userId: string, bookId: string, coverImageName: string, lang: 'fr' | 'en') {
 *         return Book.updateBookCover(userId, bookId, coverImageName, lang);
 *     }
 * ));
 *
 * // Frontend call (bookId and coverImageName needed):
 * const success = await window.electron.invoke('db:book:cover:update', bookId, coverImageName);
 */
export function createAutoHandler3<T1, T2, T3, TReturn>(
    handler: (userId: string, arg1: T1, arg2: T2, arg3: T3, lang: 'fr' | 'en') => TReturn | Promise<TReturn>
): (event: IpcMainInvokeEvent, arg1: T1, arg2: T2, arg3: T3) => Promise<TReturn> {
    return async function(event: IpcMainInvokeEvent, arg1: T1, arg2: T2, arg3: T3): Promise<TReturn> {
        const userId = getUserIdFromSession();
        const lang = getLangFromSession();

        if (!userId) {
            throw new Error('User not authenticated');
        }

        try {
            return await handler(userId, arg1, arg2, arg3, lang);
        } catch (error: unknown) {
            if (error instanceof Error) {
                console.error(`[DB] ${error.message}`);
                throw error;
            }
            throw new Error('An unknown error occurred.');
        }
    };
}

export function createUniqueId(): string {
    return crypto.randomUUID();
}

export function getCurrentDate(): string {
    return new Date().toISOString();
}