/**
 * API Client Module
 * Handles all API communications with the backend
 */

class APIClient {
    constructor() {
        this.baseURL = '';
    }

    /**
     * Fetch challenges based on user preferences (dry run)
     * @param {string} preferences - User preferences
     * @returns {Promise<Object>} Challenge data
     */
    async fetchChallenges(preferences) {
        const response = await fetch('/api/topcoder-dry-run', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                preferences: preferences || ''
            })
        });

        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }

        const data = await response.json();
        
        if (data.error) {
            throw new Error(data.error);
        }

        return data;
    }

    /**
     * Register or update user preferences
     * @param {string} email - User email
     * @param {string} preferences - User preferences
     * @returns {Promise<Object>} Registration result
     */
    async registerUser(email, preferences) {
        const response = await fetch('/api/register-user', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                email: email,
                preferences: preferences || ''
            })
        });

        if (!response.ok) {
            const errorData = await response.json();
            throw new Error(errorData.detail || `HTTP error! status: ${response.status}`);
        }

        return await response.json();
    }

    /**
     * Update existing user preferences
     * @param {string} email - User email
     * @param {string} preferences - Updated preferences
     * @returns {Promise<Object>} Update result
     */
    async updateUserPreferences(email, preferences) {
        const response = await fetch('/api/update-preferences', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                email: email,
                preferences: preferences || ''
            })
        });

        if (!response.ok) {
            const errorData = await response.json();
            throw new Error(errorData.detail || `HTTP error! status: ${response.status}`);
        }

        return await response.json();
    }

    /**
     * Toggle user active status
     * @param {string} email - User email
     * @param {boolean} active - Active status
     * @returns {Promise<Object>} Toggle result
     */
    async toggleUserActive(email, active) {
        const response = await fetch('/api/toggle-user', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                email: email,
                active: active
            })
        });

        if (!response.ok) {
            const errorData = await response.json();
            throw new Error(errorData.detail || `HTTP error! status: ${response.status}`);
        }

        return await response.json();
    }

    /**
     * Get user by email
     * @param {string} email - User email
     * @returns {Promise<Object>} User data
     */
    async getUserByEmail(email) {
        const response = await fetch(`/api/user/${encodeURIComponent(email)}`);
        
        if (!response.ok) {
            if (response.status === 404) {
                return null; // User not found
            }
            const errorData = await response.json();
            throw new Error(errorData.detail || `HTTP error! status: ${response.status}`);
        }

        const data = await response.json();
        return data.success ? data.user : null;
    }

    /**
     * Trigger daily notifications for testing
     * @returns {Promise<Object>} Trigger result
     */
    async triggerDailyNotifications() {
        const response = await fetch('/api/trigger-daily-notifications', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            }
        });

        if (!response.ok) {
            const errorData = await response.json();
            throw new Error(errorData.detail || `HTTP error! status: ${response.status}`);
        }

        return await response.json();
    }
}

// Create and export a singleton instance
const apiClient = new APIClient();