// Authentication module for handling login/logout and session management
class AuthManager {
    constructor() {
        this.user = null;
        this.isAuthenticated = false;
    }
    
    // Initialize authentication state
    async init() {
        await this.checkSession();
        this.setupAuthListeners();
    }
    
    // Check current session status
    async checkSession() {
        try {
            const response = await apiClient.get('/auth/session');
            
            if (response.authenticated) {
                this.isAuthenticated = true;
                this.user = response.user;
                this.updateUI();
                return true;
            } else {
                this.isAuthenticated = false;
                this.user = null;
                this.updateUI();
                return false;
            }
        } catch (error) {
            console.error('Session check failed:', error);
            this.isAuthenticated = false;
            this.user = null;
            this.updateUI();
            return false;
        }
    }
    
    // Login with email and password
    async login(email, password) {
        try {
            const response = await apiClient.post('/auth/login', {
                email,
                password
            });
            
            if (response.success) {
                this.isAuthenticated = true;
                this.user = response.user;
                this.updateUI();
                return { success: true };
            } else {
                return { success: false, error: response.error };
            }
        } catch (error) {
            console.error('Login error:', error);
            return { success: false, error: error.message || 'Login failed' };
        }
    }
    
    // Logout current user
    async logout() {
        try {
            await apiClient.post('/auth/logout');
            this.isAuthenticated = false;
            this.user = null;
            this.updateUI();
            
            // Redirect to login page
            window.location.href = '/login.html';
        } catch (error) {
            console.error('Logout error:', error);
            // Force logout on client side even if server request fails
            this.isAuthenticated = false;
            this.user = null;
            this.updateUI();
            window.location.href = '/login.html';
        }
    }
    
    // Update UI based on authentication state
    updateUI() {
        // Update user info display
        const userInfo = document.getElementById('user-info');
        if (userInfo) {
            if (this.isAuthenticated && this.user) {
                userInfo.innerHTML = `
                    <span>Welcome, ${this.user.name || this.user.email}</span>
                    <button id="logout-btn" class="btn btn-secondary">Logout</button>
                `;
                
                // Add logout button listener
                const logoutBtn = document.getElementById('logout-btn');
                if (logoutBtn) {
                    logoutBtn.addEventListener('click', () => this.logout());
                }
            } else {
                userInfo.innerHTML = '';
            }
        }
        
        // Show/hide admin elements
        const adminElements = document.querySelectorAll('.admin-only');
        adminElements.forEach(element => {
            if (this.isAuthenticated && this.user?.isAdmin) {
                element.style.display = 'block';
            } else {
                element.style.display = 'none';
            }
        });
        
        // Show/hide authenticated elements
        const authElements = document.querySelectorAll('.auth-only');
        authElements.forEach(element => {
            if (this.isAuthenticated) {
                element.style.display = 'block';
            } else {
                element.style.display = 'none';
            }
        });
    }

    // Redirect to appropriate dashboard
    redirectToDashboard() {
        if (this.isAuthenticated && this.user) {
            if (this.user.isAdmin) {
                window.location.href = '/admin.html';
            } else {
                window.location.href = '/dashboard.html';
            }
        } else {
            window.location.href = '/login.html';
        }
    }

    // Set up event listeners for auth-related actions
    setupAuthListeners() {
        // Global logout button
        document.addEventListener('click', (e) => {
            if (e.target.matches('[data-action="logout"]')) {
                e.preventDefault();
                this.logout();
            }
        });
        
        // Login form submission
        const loginForm = document.getElementById('login-form');
        if (loginForm) {
            loginForm.addEventListener('submit', async (e) => {
                e.preventDefault();
                
                const email = document.getElementById('email').value.trim();
                const password = document.getElementById('password').value;
                
                const result = await this.login(email, password);
                
                if (result.success) {
                    // Redirect to admin panel
                    window.location.href = '/admin.html';
                } else {
                    // Show error message
                    const errorElement = document.getElementById('error-message');
                    if (errorElement) {
                        errorElement.textContent = result.error;
                        errorElement.style.display = 'block';
                    }
                }
            });
        }
    }
    
    // Require authentication for current page
    requireAuth() {
        if (!this.isAuthenticated) {
            window.location.href = '/login.html';
            return false;
        }
        return true;
    }
    
    // Require admin access for current page
    requireAdmin() {
        if (!this.isAuthenticated) {
            window.location.href = '/login.html';
            return false;
        }
        
        if (!this.user?.isAdmin) {
            alert('Admin access required');
            window.location.href = '/';
            return false;
        }
        
        return true;
    }

    // Change user password
    async changePassword(currentPassword, newPassword) {
        try {
            const response = await apiClient.post('/auth/change-password', {
                currentPassword,
                newPassword
            });

            if (response.success) {
                return {
                    success: true,
                    message: response.message || 'Password changed successfully'
                };
            } else {
                return {
                    success: false,
                    error: response.error || 'Failed to change password'
                };
            }
        } catch (error) {
            console.error('Change password failed:', error);
            return {
                success: false,
                error: error.message || 'Failed to change password. Please try again.'
            };
        }
    }
}

// Create global auth manager instance
const authManager = new AuthManager();

// Initialize when DOM is ready
document.addEventListener('DOMContentLoaded', () => {
    authManager.init();
});

// Export for use in other modules
if (typeof module !== 'undefined' && module.exports) {
    module.exports = AuthManager;
}