/**
 * 认证模块管理器
 * 处理登录、注册、注销及权限检查
 * 适配 Bootstrap 5 样式
 */
class AuthManager {
    constructor() {
        this.apiBase = '/api';
        this.init();
    }
    
    init() {
        this.createNotificationContainer();
        this.initEventListeners();
        this.checkAuthStatus();
    }
    
    /**
     * 创建通知容器 (适配 Bootstrap Toast)
     */
    createNotificationContainer() {
        if (!document.getElementById('notification-container')) {
            const container = document.createElement('div');
            container.id = 'notification-container';
            container.className = 'toast-container position-fixed top-0 end-0 p-3';
            container.style.zIndex = '9999';
            document.body.appendChild(container);
        }
    }
    
    /**
     * 检查用户认证状态
     */
    async checkAuthStatus() {
        const currentPath = window.location.pathname;
        const isAuthPage = currentPath.includes('/login') || currentPath.includes('/register');
        
        try {
            const response = await fetch(`${this.apiBase}/auth/me`);
            const data = await response.json();
            
            if (data.success && data.data && data.data.user) {
                const redirectUrl = this.getDashboardUrl(data.data.user.role);
                if (isAuthPage || currentPath === '/') {
                    window.location.href = redirectUrl;
                }
            }
        } catch (error) {
            console.error('Auth check failed:', error);
        }
    }
    
    getDashboardUrl(role) {
        switch(role) {
            case 'student': return '/student/dashboard';
            case 'teacher': return '/teacher/dashboard';
            case 'admin': return '/admin/dashboard';
            default: return '/dashboard';
        }
    }
    
    initEventListeners() {
        // 登录表单
        const loginForm = document.getElementById('loginForm');
        if (loginForm) {
            loginForm.addEventListener('submit', (e) => this.handleLogin(e));
        }
        
        // 注册表单
        const registerForm = document.getElementById('registerForm');
        if (registerForm) {
            registerForm.addEventListener('submit', (e) => this.handleRegister(e));
            
            // 角色选择联动
            const roleSelect = document.getElementById('role');
            if (roleSelect) {
                roleSelect.addEventListener('change', (e) => this.handleRoleChange(e));
            }
        }
        
        // 注销按钮
        document.querySelectorAll('.btn-logout, #logoutBtn').forEach(btn => {
            btn.addEventListener('click', (e) => this.handleLogout(e));
        });
    }
    
    handleRoleChange(e) {
        const role = e.target.value;
        const classField = document.getElementById('classField');
        const classInput = document.getElementById('class');
        
        if (classField && classInput) {
            if (role === 'student' || role === 'teacher') {
                classField.style.display = 'flex'; // 配合 Bootstrap input-group
                classInput.required = true;
            } else {
                classField.style.display = 'none';
                classInput.required = false;
                classInput.value = '';
            }
        }
    }
    
    async handleLogin(e) {
        e.preventDefault();
        const form = e.target;
        const submitBtn = document.getElementById('loginBtn') || form.querySelector('button[type="submit"]');
        
        if (this.setLoading(submitBtn, true)) {
            try {
                const formData = new FormData(form);
                const data = Object.fromEntries(formData.entries());
                
                const response = await fetch(`${this.apiBase}/auth/login`, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify(data)
                });
                
                const result = await response.json();
                
                if (result.success) {
                    this.showNotification('登录成功，正在跳转...', 'success');
                    
                    // 获取用户信息，优先从 result.data.user 获取，兼容旧格式 result.data 或 result.user
                    const user = (result.data && result.data.user) || result.data || result.user;
                    const role = user ? user.role : null;
                    
                    if (role) {
                        setTimeout(() => {
                            window.location.href = this.getDashboardUrl(role);
                        }, 1000);
                    } else {
                        console.error('Login success but role not found:', result);
                        this.showNotification('登录状态异常，请重试', 'error');
                        this.setLoading(submitBtn, false);
                    }
                } else {
                    this.showNotification(result.message || '登录失败', 'error');
                    this.setLoading(submitBtn, false);
                }
            } catch (error) {
                console.error('Login error:', error);
                this.showNotification('服务器连接失败，请稍后重试', 'error');
                this.setLoading(submitBtn, false);
            }
        }
    }
    
    async handleRegister(e) {
        e.preventDefault();
        const form = e.target;
        const submitBtn = document.getElementById('registerBtn') || form.querySelector('button[type="submit"]');
        
        const formData = new FormData(form);
        const data = Object.fromEntries(formData.entries());
        
        if (data.password !== data.confirmPassword) {
            this.showNotification('两次输入的密码不一致', 'error');
            return;
        }
        
        if (this.setLoading(submitBtn, true)) {
            try {
                const response = await fetch(`${this.apiBase}/auth/register`, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify(data)
                });
                
                const result = await response.json();
                
                if (result.success) {
                    this.showNotification('注册成功，请登录', 'success');
                    setTimeout(() => {
                        window.location.href = '/login';
                    }, 1500);
                } else {
                    this.showNotification(result.message || '注册失败', 'error');
                    this.setLoading(submitBtn, false);
                }
            } catch (error) {
                console.error('Register error:', error);
                this.showNotification('服务器连接失败，请稍后重试', 'error');
                this.setLoading(submitBtn, false);
            }
        }
    }
    
    async handleLogout(e) {
        e.preventDefault();
        if (confirm('确定要退出登录吗？')) {
            try {
                const response = await fetch(`${this.apiBase}/auth/logout`, {
                    method: 'POST'
                });
                const result = await response.json();
                if (result.success) {
                    alert('退出登录成功');
                    window.location.href = '/login';
                } else {
                    alert(result.message || '退出登录失败');
                }
            } catch (error) {
                console.error('Logout error:', error);
                alert('退出登录出错');
            }
        }
    }
    
    /**
     * 设置按钮加载状态
     */
    setLoading(btn, isLoading) {
        if (!btn) return false;
        
        const spinner = btn.querySelector('.spinner-border');
        if (isLoading) {
            if (btn.disabled) return false;
            btn.disabled = true;
            if (spinner) spinner.classList.remove('d-none');
        } else {
            btn.disabled = false;
            if (spinner) spinner.classList.add('d-none');
        }
        return true;
    }
    
    /**
     * 显示通知 (Bootstrap 5 Toast)
     */
    showNotification(message, type = 'info') {
        const container = document.getElementById('notification-container');
        if (!container) return;
        
        const iconMap = {
            success: 'fa-check-circle',
            error: 'fa-exclamation-circle',
            warning: 'fa-exclamation-triangle',
            info: 'fa-info-circle'
        };
        
        const bgMap = {
            success: 'bg-success',
            error: 'bg-danger',
            warning: 'bg-warning',
            info: 'bg-info'
        };

        const toastId = 'toast-' + Date.now();
        const toastHtml = `
            <div id="${toastId}" class="toast align-items-center text-white ${bgMap[type]} border-0" role="alert" aria-live="assertive" aria-atomic="true">
                <div class="d-flex">
                    <div class="toast-body">
                        <i class="fas ${iconMap[type]} me-2"></i>
                        ${message}
                    </div>
                    <button type="button" class="btn-close btn-close-white me-2 m-auto" data-bs-dismiss="toast" aria-label="Close"></button>
                </div>
            </div>
        `;

        container.insertAdjacentHTML('beforeend', toastHtml);
        const toastElement = document.getElementById(toastId);
        const toast = new bootstrap.Toast(toastElement, { delay: 3000 });
        toast.show();
        
        toastElement.addEventListener('hidden.bs.toast', () => {
            toastElement.remove();
        });
    }
}

// 初始化认证管理器
document.addEventListener('DOMContentLoaded', () => {
    window.authManager = new AuthManager();
});