import { GreenPage } from '../types';
import { createEmptyPage, createNewPage } from './mockDataService';

const USERS_KEY = 'greenpage_users';
const CURRENT_USER_KEY = 'greenpage_currentUser';

// Simulate a database
const getDb = () => {
    try {
        const db = localStorage.getItem(USERS_KEY);
        return db ? JSON.parse(db) : {};
    } catch (error) {
        console.error("Error reading from localStorage", error);
        return {};
    }
};

const saveDb = (db: any) => {
    try {
        localStorage.setItem(USERS_KEY, JSON.stringify(db));
    } catch (error) {
        console.error("Error writing to localStorage", error);
    }
};

export const authService = {
    register: (email: string, password: string): { success: boolean; message: string } => {
        const db = getDb();
        if (db[email]) {
            return { success: false, message: 'User with this email already exists.' };
        }
        const initialPage = createNewPage('My First Page');
        db[email] = { password, pages: [initialPage] };
        saveDb(db);
        authService.login(email, password);
        return { success: true, message: 'Registration successful.' };
    },

    login: (email: string, password: string): { success: boolean; message: string } => {
        const db = getDb();
        const user = db[email];
        if (user && user.password === password) {
            localStorage.setItem(CURRENT_USER_KEY, email);
            return { success: true, message: 'Login successful.' };
        }
        return { success: false, message: 'Invalid email or password.' };
    },

    logout: (): void => {
        localStorage.removeItem(CURRENT_USER_KEY);
    },

    getCurrentUser: (): string | null => {
        return localStorage.getItem(CURRENT_USER_KEY);
    },

    getUserPages: (): GreenPage[] | null => {
        const currentUser = authService.getCurrentUser();
        if (!currentUser) return null;

        const db = getDb();
        const user = db[currentUser];
        
        if (user && (!user.pages || user.pages.length === 0)) {
            const initialPage = createNewPage('My First Page');
            user.pages = [initialPage];
            saveDb(db);
        }

        return user ? user.pages : null;
    },

    saveUserPages: (pages: GreenPage[]): void => {
        const currentUser = authService.getCurrentUser();
        if (!currentUser) return;

        const db = getDb();
        if (db[currentUser]) {
            db[currentUser].pages = pages;
            saveDb(db);
        }
    },
};