/**
 * API Client Wrapper
 * Centralized API communication with auth handling
 */

const api = {
    /**
     * Get the auth token from localStorage
     */
    getToken() {
        return localStorage.getItem('access_token');
    },

    /**
     * Set the auth token
     */
    setToken(token) {
        localStorage.setItem('access_token', token);
    },

    /**
     * Clear the auth token
     */
    clearToken() {
        localStorage.removeItem('access_token');
        this.clearCache();
    },

    /**
     * Get data with caching - Returns Response obj or Mock Response
     * @param {string} url - API endpoint
     * @param {number} ttlMinutes - Time to live in minutes (default 60)
     */
    async getCached(url, ttlMinutes = 60) {
        const cacheKey = 'cache_' + url;
        const cachedItem = localStorage.getItem(cacheKey);

        if (cachedItem) {
            try {
                const { data, timestamp } = JSON.parse(cachedItem);
                const age = (Date.now() - timestamp) / 1000 / 60;

                if (age < ttlMinutes) {
                    console.log(`[Cache] Hit for ${url}`);
                    // Return a mock response-like object
                    return {
                        ok: true,
                        status: 200,
                        json: async () => data
                    };
                } else {
                    console.log(`[Cache] Expired for ${url}`);
                    localStorage.removeItem(cacheKey);
                }
            } catch (e) {
                console.error('[Cache] Error parsing cache', e);
                localStorage.removeItem(cacheKey);
            }
        }

        console.log(`[Cache] Miss for ${url}`);
        const response = await this.get(url);

        if (response && response.ok) {
            try {
                // Clone response to read body and still return it to caller
                const clone = response.clone();
                const data = await clone.json();

                localStorage.setItem(cacheKey, JSON.stringify({
                    data: data,
                    timestamp: Date.now()
                }));
            } catch (e) {
                console.warn('[Cache] failed to save to localStorage', e);
            }
        }

        return response;
    },

    /**
     * Invalidate specific cache key
     */
    invalidateCache(url) {
        localStorage.removeItem('cache_' + url);
        console.log(`[Cache] Invalidated ${url}`);
    },

    /**
     * Clear all API cache
     */
    clearCache() {
        Object.keys(localStorage).forEach(key => {
            if (key.startsWith('cache_')) {
                localStorage.removeItem(key);
            }
        });
        console.log('[Cache] Cleared all cache');
    },

    /**
     * Check if user is authenticated (token or Authelia)
     */
    isAuthenticated() {
        return !!this.getToken() || this._autheliaAuth;
    },

    /**
     * Check authentication - works with both JWT and Authelia
     * Call this on page load to verify auth status
     */
    async checkAuth() {
        const url = '/api/auth/me';
        // 1. Try Cache (Short TTL: 5 min)
        const cacheKey = 'cache_' + url;
        const cachedItem = localStorage.getItem(cacheKey);
        if (cachedItem) {
            try {
                const { data, timestamp } = JSON.parse(cachedItem);
                if ((Date.now() - timestamp) / 1000 / 60 < 5) {
                    this._autheliaAuth = true;
                    return data;
                }
            } catch (e) { localStorage.removeItem(cacheKey); }
        }

        // 2. Fetch from Network
        const response = await fetch(url, {
            headers: this.getToken() ? { 'Authorization': `Bearer ${this.getToken()}` } : {}
        });

        if (response.ok) {
            this._autheliaAuth = true;
            const data = await response.json();

            // Save to Cache
            localStorage.setItem(cacheKey, JSON.stringify({
                data: data,
                timestamp: Date.now()
            }));

            return data;
        }

        this._autheliaAuth = false;
        return null;
    },

    /**
     * Redirect to login if not authenticated
     * Returns user object if authenticated, null otherwise
     */
    async requireAuth() {
        const user = await this.checkAuth();
        if (!user) {
            window.location.href = '/login';
            return null;
        }
        return user;
    },

    /**
     * Make an API request
     */
    async request(method, url, data = null) {
        const options = {
            method,
            headers: {}
        };

        const token = this.getToken();
        if (token) {
            options.headers['Authorization'] = `Bearer ${token}`;
        }

        if (data) {
            options.headers['Content-Type'] = 'application/json';
            options.body = JSON.stringify(data);
        }

        const response = await fetch(url, options);

        // Handle 401 - redirect to login
        if (response.status === 401) {
            this.clearToken();
            window.location.href = '/login';
            return null;
        }

        return response;
    },

    /**
     * GET request
     */
    async get(url) {
        return this.request('GET', url);
    },

    /**
     * POST request
     */
    async post(url, data) {
        return this.request('POST', url, data);
    },

    /**
     * PUT request
     */
    async put(url, data) {
        return this.request('PUT', url, data);
    },

    /**
     * PATCH request
     */
    async patch(url, data) {
        return this.request('PATCH', url, data);
    },

    /**
     * DELETE request
     */
    async delete(url) {
        return this.request('DELETE', url);
    },

    /**
     * Get current user info
     */
    async getCurrentUser() {
        const response = await this.get('/api/auth/me');
        if (response && response.ok) {
            return await response.json();
        }
        return null;
    },

    /**
     * Login
     */
    async login(email, password) {
        const response = await fetch('/api/auth/login', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ email, password })
        });

        if (response.ok) {
            const data = await response.json();
            this.setToken(data.access_token);
            return { success: true };
        }

        const error = await response.json();
        return { success: false, error: error.detail || 'Login fallito' };
    },

    /**
     * Register
     */
    async register(email, password, name) {
        const response = await fetch('/api/auth/register', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ email, password, name })
        });

        if (response.ok) {
            const data = await response.json();
            this.setToken(data.access_token);
            return { success: true };
        }

        const error = await response.json();
        return { success: false, error: error.detail || 'Registrazione fallita' };
    },

    /**
     * Logout
     */
    async logout() {
        // Fetch config to check for external logout URL
        let logoutUrl = '/login';
        try {
            const configRes = await this.get('/api/auth/config');
            if (configRes && configRes.ok) {
                const config = await configRes.json();
                if (config.authelia_enabled && config.logout_url) {
                    logoutUrl = config.logout_url;
                }
            }
        } catch (e) {
            console.error('Error fetching logout config', e);
        }

        await this.post('/api/auth/logout', {});
        this.clearToken();
        window.location.href = logoutUrl;
    }
};

// Make globally available
window.api = api;