/**
 * API Service - Handles all API communication
 */
const ApiService = {
    /**
     * Base URL for API calls
     */
    baseUrl: 'api.php',

    /**
     * Check if user session is valid
     * @returns {Promise<{authenticated: boolean, user?: string}>}
     */
    async checkSession() {
        const res = await fetch(`${this.baseUrl}?action=check_session`);
        return res.json();
    },

    /**
     * Login user
     * @param {string} username 
     * @param {string} password 
     * @returns {Promise<{success?: boolean, user?: string, error?: string}>}
     */
    async login(username, password) {
        const res = await fetch(`${this.baseUrl}?action=login`, {
            method: 'POST',
            body: JSON.stringify({ username, password })
        });
        return { ok: res.ok, data: await res.json() };
    },

    /**
     * Logout user
     * @returns {Promise<{success: boolean}>}
     */
    async logout() {
        const res = await fetch(`${this.baseUrl}?action=logout`);
        return res.json();
    },

    /**
     * Get all products
     * @returns {Promise<Array>}
     */
    async getProducts() {
        const res = await fetch(`${this.baseUrl}?action=get_products`);
        if (res.ok) {
            return res.json();
        }
        return [];
    },

    /**
     * Lookup address by postcode and house number
     * @param {string} postcode 
     * @param {string} number 
     * @returns {Promise<{street?: string, city?: string, error?: string}>}
     */
    async lookupPostcode(postcode, number) {
        const res = await fetch(
            `${this.baseUrl}?action=postcode_check&postcode=${encodeURIComponent(postcode)}&number=${encodeURIComponent(number)}`
        );
        return res.json();
    },

    /**
     * Create a new order
     * @param {Object} orderData 
     * @returns {Promise<{success?: boolean, order_id?: number, total?: string, error?: string}>}
     */
    async createOrder(orderData) {
        const res = await fetch(`${this.baseUrl}?action=create_order`, {
            method: 'POST',
            body: JSON.stringify(orderData)
        });
        return res.json();
    }
};