// Authentication Module for GopherGate Dashboard

class AuthManager {
    constructor() {
        this.isAuthenticated = false;
        this.token = null;
        this.user = null;
        this.init();
    }

    init() {
        // Check for existing session
        const savedToken = localStorage.getItem('dashboard_token');
        const savedUser = localStorage.getItem('dashboard_user');
        
        if (savedToken && savedUser) {
            this.token = savedToken;
            this.user = JSON.parse(savedUser);
            this.isAuthenticated = true;
            this.showDashboard();
        } else {
            this.showLogin();
        }

        // Setup login form
        this.setupLoginForm();
        this.setupLogout();
    }

    setupLoginForm() {
        const loginForm = document.getElementById('login-form');
        if (!loginForm) return;

        loginForm.addEventListener('submit', async (e) => {
            e.preventDefault();
            
            const username = document.getElementById('username').value;
            const password = document.getElementById('password').value;
            
            await this.login(username, password);
        });
    }

    setupLogout() {
        const logoutBtn = document.getElementById('logout-btn');
        if (!logoutBtn) return;

        logoutBtn.addEventListener('click', () => {
            this.logout();
        });
    }

    setToken(newToken) {
        if (!newToken) return;
        this.token = newToken;
        localStorage.setItem('dashboard_token', this.token);
    }

    async login(username, password) {
        const errorElement = document.getElementById('login-error');
        const loginBtn = document.querySelector('.login-btn');
        
        try {
            loginBtn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Authenticating...';
            loginBtn.disabled = true;
            
            const response = await fetch('/api/auth/login', {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ username, password })
            });
            
            const result = await response.json();
            
            if (result.success) {
                this.token = result.data.token;
                this.user = result.data.user;
                
                localStorage.setItem('dashboard_token', this.token);
                localStorage.setItem('dashboard_user', JSON.stringify(this.user));
                
                this.isAuthenticated = true;
                this.showDashboard();
                this.showToast('Successfully logged in!', 'success');
            } else {
                throw new Error(result.error || 'Invalid credentials');
            }
        } catch (error) {
            errorElement.style.display = 'flex';
            errorElement.querySelector('span').textContent = error.message;
            loginBtn.innerHTML = '<i class="fas fa-sign-in-alt"></i> Sign In';
            loginBtn.disabled = false;
        }
    }

    async logout() {
        // Revoke server-side session first
        try {
            if (this.token) {
                await fetch('/api/auth/logout', {
                    method: 'POST',
                    headers: { 'Authorization': `Bearer ${this.token}` }
                });
            }
        } catch (e) {
            // Best-effort — still clear local state even if server call fails
            console.warn('Server logout failed:', e);
        }

        // Clear localStorage
        localStorage.removeItem('dashboard_token');
        localStorage.removeItem('dashboard_user');
        
        // Reset state
        this.isAuthenticated = false;
        this.token = null;
        this.user = null;
        
        // Show login screen
        this.showLogin();
        
        // Show logout message
        this.showToast('Successfully logged out', 'info');
    }

    showLogin() {
        const loginScreen = document.getElementById('login-screen');
        const dashboard = document.getElementById('dashboard');
        
        if (loginScreen) loginScreen.style.display = 'flex';
        if (dashboard) dashboard.style.display = 'none';
        
        // Clear form
        const loginForm = document.getElementById('login-form');
        if (loginForm) loginForm.reset();
        
        // Hide error
        const errorElement = document.getElementById('login-error');
        if (errorElement) errorElement.style.display = 'none';
        
        // Reset button
        const loginBtn = document.querySelector('.login-btn');
        if (loginBtn) {
            loginBtn.innerHTML = '<i class="fas fa-sign-in-alt"></i> Sign In';
            loginBtn.disabled = false;
        }
    }

    showDashboard() {
        const loginScreen = document.getElementById('login-screen');
        const dashboard = document.getElementById('dashboard');
        
        if (loginScreen) loginScreen.style.display = 'none';
        if (dashboard) dashboard.style.display = 'flex';
        
        // Update user info in sidebar
        this.updateUserInfo();
        
        // Initialize dashboard components
        if (typeof window.initDashboard === 'function') {
            window.initDashboard();
        }
    }

    updateUserInfo() {
        const userNameElement = document.querySelector('.user-name');
        const userRoleElement = document.querySelector('.user-role');

        if (userNameElement && this.user) {
            userNameElement.textContent = this.user.name || this.user.username || 'User';
        }

        if (userRoleElement && this.user) {
            const roleLabels = { admin: 'Administrator', viewer: 'Viewer' };
            userRoleElement.textContent = roleLabels[this.user.role] || this.user.role || 'User';
        }
    }

    getAuthHeaders() {
        if (!this.token) return {};
        
        return {
            'Authorization': `Bearer ${this.token}`,
            'Content-Type': 'application/json'
        };
    }

    async fetchWithAuth(url, options = {}) {
        const headers = this.getAuthHeaders();
        
        const response = await fetch(url, {
            ...options,
            headers: {
                ...headers,
                ...options.headers
            }
        });
        
        if (response.status === 401) {
            // Token expired or invalid
            this.logout();
            throw new Error('Authentication required');
        }
        
        return response;
    }

    showToast(message, type = 'info') {
        // Create toast container if it doesn't exist
        let container = document.querySelector('.toast-container');
        if (!container) {
            container = document.createElement('div');
            container.className = 'toast-container';
            document.body.appendChild(container);
        }
        
        // Create toast
        const toast = document.createElement('div');
        toast.className = `toast ${type}`;
        
        // Set icon based on type
        let icon = 'info-circle';
        switch (type) {
            case 'success':
                icon = 'check-circle';
                break;
            case 'error':
                icon = 'exclamation-circle';
                break;
            case 'warning':
                icon = 'exclamation-triangle';
                break;
        }
        
        toast.innerHTML = `
            <i class="fas fa-${icon} toast-icon"></i>
            <div class="toast-content">
                <div class="toast-title">${type.charAt(0).toUpperCase() + type.slice(1)}</div>
                <div class="toast-message">${message}</div>
            </div>
            <button class="toast-close">
                <i class="fas fa-times"></i>
            </button>
        `;
        
        // Add close functionality
        const closeBtn = toast.querySelector('.toast-close');
        closeBtn.addEventListener('click', () => {
            toast.remove();
        });
        
        // Add to container
        container.appendChild(toast);
        
        // Auto-remove after 5 seconds
        setTimeout(() => {
            if (toast.parentNode) {
                toast.remove();
            }
        }, 5000);
    }
}

// Initialize auth manager when DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
    window.authManager = new AuthManager();
});

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