// API Client for making requests to the backend
class APIClient {
    constructor() {
        this.baseURL = '/api';
        this.csrfToken = null;
        this.csrfTokenPromise = null;
    }

    /**
     * Fetch CSRF token from the server
     */
    async fetchCsrfToken() {
        // If we're already fetching, return the existing promise
        if (this.csrfTokenPromise) {
            return this.csrfTokenPromise;
        }

        this.csrfTokenPromise = (async () => {
            try {
                console.log('Fetching CSRF token from server...');
                const response = await fetch(`${this.baseURL}/csrf-token`, {
                    credentials: 'include' // Important: include cookies
                });
                const data = await response.json();
                this.csrfToken = data.csrfToken;
                console.log('CSRF token received:', this.csrfToken ? 'Token obtained' : 'No token');
                return this.csrfToken;
            } catch (error) {
                console.error('Failed to fetch CSRF token:', error);
                this.csrfToken = null;
                throw error;
            } finally {
                this.csrfTokenPromise = null;
            }
        })();

        return this.csrfTokenPromise;
    }

    /**
     * Ensure we have a valid CSRF token
     */
    async ensureCsrfToken() {
        if (!this.csrfToken) {
            await this.fetchCsrfToken();
        }
        return this.csrfToken;
    }

    async makeRequest(endpoint, options = {}, isRetry = false) {
        // For state-changing methods, ensure we have a CSRF token
        const needsCsrf = ['POST', 'PUT', 'PATCH', 'DELETE'].includes(options.method);
        
        if (needsCsrf) {
            await this.ensureCsrfToken();
        }

        const config = {
            headers: {
                'Content-Type': 'application/json',
                ...(needsCsrf && this.csrfToken ? { 'X-CSRF-Token': this.csrfToken } : {}),
                ...options.headers
            },
            credentials: 'include', // Important: include cookies for CSRF
            ...options
        };

        try {
            const response = await fetch(`${this.baseURL}${endpoint}`, config);
            const data = await response.json();

            // If response includes a new CSRF token, update it
            if (data.csrfToken) {
                this.csrfToken = data.csrfToken;
            }

            if (!response.ok) {
                // If CSRF token is invalid and we haven't retried yet, fetch a new one and retry once
                if (!isRetry && response.status === 403 && data.error && data.error.includes('CSRF')) {
                    console.log('CSRF token invalid, fetching new token and retrying...');
                    this.csrfToken = null;
                    await this.fetchCsrfToken();
                    // Retry the request once with new token
                    return this.makeRequest(endpoint, options, true);
                }

                // Create enhanced error with response data for better error handling
                const error = new Error(data.error || data.message || `HTTP ${response.status}`);
                error.status = response.status;
                error.data = data;
                throw error;
            }

            return data;
        } catch (error) {
            console.error('API request failed:', error);
            throw error;
        }
    }

    async get(endpoint) {
        return this.makeRequest(endpoint, {
            method: 'GET'
        });
    }

    async post(endpoint, data) {
        return this.makeRequest(endpoint, {
            method: 'POST',
            body: JSON.stringify(data)
        });
    }

    async put(endpoint, data) {
        return this.makeRequest(endpoint, {
            method: 'PUT',
            body: JSON.stringify(data)
        });
    }

    async patch(endpoint, data) {
        return this.makeRequest(endpoint, {
            method: 'PATCH',
            body: JSON.stringify(data)
        });
    }

    async delete(endpoint) {
        return this.makeRequest(endpoint, {
            method: 'DELETE'
        });
    }

    async postFormData(endpoint, formData, isRetry = false) {
        // Ensure we have a CSRF token for POST requests
        await this.ensureCsrfToken();
        
        console.log('Sending FormData with CSRF token:', this.csrfToken ? 'Token present' : 'No token');
        
        // Add CSRF token to form data AND headers
        if (this.csrfToken) {
            formData.set('_csrf', this.csrfToken);
        }

        // Don't set Content-Type header - browser will set it with boundary for multipart/form-data
        // But DO set CSRF token header
        const config = {
            method: 'POST',
            headers: {
                ...(this.csrfToken ? { 'X-CSRF-Token': this.csrfToken } : {})
            },
            body: formData,
            credentials: 'include' // Important: include cookies for CSRF
        };

        try {
            const response = await fetch(`${this.baseURL}${endpoint}`, config);
            const data = await response.json();

            // If response includes a new CSRF token, update it
            if (data.csrfToken) {
                this.csrfToken = data.csrfToken;
            }

            if (!response.ok) {
                // If CSRF token is invalid and we haven't retried yet, fetch a new one and retry once
                if (!isRetry && response.status === 403 && data.error && data.error.includes('CSRF')) {
                    console.log('CSRF token invalid, fetching new token and retrying...');
                    this.csrfToken = null;
                    await this.fetchCsrfToken();
                    // Update form data with new token
                    formData.set('_csrf', this.csrfToken);
                    // Retry the request once with new token
                    return this.postFormData(endpoint, formData, true);
                }

                const error = new Error(data.error || data.message || `HTTP ${response.status}`);
                error.status = response.status;
                error.data = data;
                throw error;
            }

            return data;
        } catch (error) {
            console.error('API request failed:', error);
            throw error;
        }
    }

    async putFormData(endpoint, formData, isRetry = false) {
        // Ensure we have a CSRF token for PUT requests
        await this.ensureCsrfToken();
        
        // Add CSRF token to form data AND headers
        if (this.csrfToken) {
            formData.set('_csrf', this.csrfToken);
        }

        // Don't set Content-Type header - browser will set it with boundary for multipart/form-data
        // But DO set CSRF token header
        const config = {
            method: 'PUT',
            headers: {
                ...(this.csrfToken ? { 'X-CSRF-Token': this.csrfToken } : {})
            },
            body: formData,
            credentials: 'include' // Important: include cookies for CSRF
        };

        try {
            const response = await fetch(`${this.baseURL}${endpoint}`, config);
            const data = await response.json();

            // If response includes a new CSRF token, update it
            if (data.csrfToken) {
                this.csrfToken = data.csrfToken;
            }

            if (!response.ok) {
                // If CSRF token is invalid and we haven't retried yet, fetch a new one and retry once
                if (!isRetry && response.status === 403 && data.error && data.error.includes('CSRF')) {
                    console.log('CSRF token invalid, fetching new token and retrying...');
                    this.csrfToken = null;
                    await this.fetchCsrfToken();
                    // Update form data with new token
                    formData.set('_csrf', this.csrfToken);
                    // Retry the request once with new token
                    return this.putFormData(endpoint, formData, true);
                }

                const error = new Error(data.error || data.message || `HTTP ${response.status}`);
                error.status = response.status;
                error.data = data;
                throw error;
            }

            return data;
        } catch (error) {
            console.error('API request failed:', error);
            throw error;
        }
    }

    // Health check
    async checkHealth() {
        return this.get('/health');
    }

    // Test Represent API connection
    async testRepresent() {
        return this.get('/test-represent');
    }

    // Get representatives by postal code
    async getRepresentativesByPostalCode(postalCode) {
        const cleanPostalCode = postalCode.replace(/\s/g, '').toUpperCase();
        return this.get(`/representatives/by-postal/${cleanPostalCode}`);
    }

    // Refresh representatives for postal code
    async refreshRepresentatives(postalCode) {
        const cleanPostalCode = postalCode.replace(/\s/g, '').toUpperCase();
        return this.post(`/representatives/refresh-postal/${cleanPostalCode}`);
    }

    // Send email to representative
    async sendEmail(emailData) {
        return this.post('/emails/send', emailData);
    }

    // Preview email before sending
    async previewEmail(emailData) {
        return this.post('/emails/preview', emailData);
    }
}

// Create global instance
window.apiClient = new APIClient();