/**
 * Token管理工具类
 */
class TokenManager {
    
    static TOKEN_KEY = 'yundage_token';
    static USER_KEY = 'yundage_user';
    static REFRESH_TOKEN_KEY = 'yundage_refresh_token';
    
    /**
     * 保存Token到本地存储
     * @param {string} token - JWT Token
     * @param {boolean} remember - 是否记住登录状态
     */
    static saveToken(token, remember = false) {
        try {
            const storage = remember ? localStorage : sessionStorage;
            storage.setItem(this.TOKEN_KEY, token);
            
            // 解析token获取过期时间
            const payload = this.parseToken(token);
            if (payload && payload.exp) {
                storage.setItem(this.TOKEN_KEY + '_exp', payload.exp.toString());
            }
            
            console.log('Token saved successfully');
        } catch (error) {
            console.error('Failed to save token:', error);
        }
    }
    
    /**
     * 获取Token
     * @returns {string|null} Token或null
     */
    static getToken() {
        try {
            // 优先从sessionStorage获取
            let token = sessionStorage.getItem(this.TOKEN_KEY);
            
            // 如果sessionStorage没有，从localStorage获取
            if (!token) {
                token = localStorage.getItem(this.TOKEN_KEY);
            }
            
            // 检查token是否过期
            if (token && this.isTokenExpired(token)) {
                this.removeToken();
                return null;
            }
            
            return token;
        } catch (error) {
            console.error('Failed to get token:', error);
            return null;
        }
    }
    
    /**
     * 移除Token
     */
    static removeToken() {
        try {
            sessionStorage.removeItem(this.TOKEN_KEY);
            sessionStorage.removeItem(this.TOKEN_KEY + '_exp');
            localStorage.removeItem(this.TOKEN_KEY);
            localStorage.removeItem(this.TOKEN_KEY + '_exp');
            
            // 同时清除用户信息
            this.removeUser();
            
            console.log('Token removed successfully');
        } catch (error) {
            console.error('Failed to remove token:', error);
        }
    }
    
    /**
     * 检查Token是否有效
     * @returns {boolean} 是否有效
     */
    static isTokenValid() {
        const token = this.getToken();
        return token !== null && !this.isTokenExpired(token);
    }
    
    /**
     * 检查Token是否过期
     * @param {string} token - JWT Token
     * @returns {boolean} 是否过期
     */
    static isTokenExpired(token) {
        try {
            const payload = this.parseToken(token);
            if (!payload || !payload.exp) {
                return true;
            }
            
            // JWT的exp是秒级时间戳，JavaScript的Date.now()是毫秒级
            const currentTime = Math.floor(Date.now() / 1000);
            return payload.exp < currentTime;
        } catch (error) {
            console.error('Failed to check token expiration:', error);
            return true;
        }
    }
    
    /**
     * 解析JWT Token
     * @param {string} token - JWT Token
     * @returns {object|null} 解析后的payload
     */
    static parseToken(token) {
        try {
            const parts = token.split('.');
            if (parts.length !== 3) {
                throw new Error('Invalid token format');
            }
            
            const payload = parts[1];
            const decoded = atob(payload.replace(/_/g, '/').replace(/-/g, '+'));
            return JSON.parse(decoded);
        } catch (error) {
            console.error('Failed to parse token:', error);
            return null;
        }
    }
    
    /**
     * 保存用户信息
     * @param {object} user - 用户信息
     * @param {boolean} remember - 是否记住登录状态
     */
    static saveUser(user, remember = false) {
        try {
            const storage = remember ? localStorage : sessionStorage;
            storage.setItem(this.USER_KEY, JSON.stringify(user));
            console.log('User info saved successfully');
        } catch (error) {
            console.error('Failed to save user info:', error);
        }
    }
    
    /**
     * 获取用户信息
     * @returns {object|null} 用户信息或null
     */
    static getUser() {
        try {
            // 优先从sessionStorage获取
            let userStr = sessionStorage.getItem(this.USER_KEY);
            
            // 如果sessionStorage没有，从localStorage获取
            if (!userStr) {
                userStr = localStorage.getItem(this.USER_KEY);
            }
            
            return userStr ? JSON.parse(userStr) : null;
        } catch (error) {
            console.error('Failed to get user info:', error);
            return null;
        }
    }
    
    /**
     * 移除用户信息
     */
    static removeUser() {
        try {
            sessionStorage.removeItem(this.USER_KEY);
            localStorage.removeItem(this.USER_KEY);
            console.log('User info removed successfully');
        } catch (error) {
            console.error('Failed to remove user info:', error);
        }
    }
    
    /**
     * 保存刷新Token
     * @param {string} refreshToken - 刷新Token
     */
    static saveRefreshToken(refreshToken) {
        try {
            localStorage.setItem(this.REFRESH_TOKEN_KEY, refreshToken);
        } catch (error) {
            console.error('Failed to save refresh token:', error);
        }
    }
    
    /**
     * 获取刷新Token
     * @returns {string|null} 刷新Token或null
     */
    static getRefreshToken() {
        try {
            return localStorage.getItem(this.REFRESH_TOKEN_KEY);
        } catch (error) {
            console.error('Failed to get refresh token:', error);
            return null;
        }
    }
    
    /**
     * 移除刷新Token
     */
    static removeRefreshToken() {
        try {
            localStorage.removeItem(this.REFRESH_TOKEN_KEY);
        } catch (error) {
            console.error('Failed to remove refresh token:', error);
        }
    }
    
    /**
     * 清除所有认证信息
     */
    static clearAll() {
        this.removeToken();
        this.removeUser();
        this.removeRefreshToken();
        console.log('All auth data cleared');
    }
    
    /**
     * 获取Token头部信息用于HTTP请求
     * @returns {object|null} Authorization头部或null
     */
    static getAuthHeader() {
        const token = this.getToken();
        return token ? { 'Authorization': `Bearer ${token}` } : null;
    }
    
    /**
     * 检查用户是否已登录
     * @returns {boolean} 是否已登录
     */
    static isLoggedIn() {
        return this.isTokenValid() && this.getUser() !== null;
    }
    
    /**
     * 获取Token剩余有效时间（秒）
     * @returns {number} 剩余秒数，-1表示已过期或无效
     */
    static getTokenRemainingTime() {
        const token = this.getToken();
        if (!token) return -1;
        
        const payload = this.parseToken(token);
        if (!payload || !payload.exp) return -1;
        
        const currentTime = Math.floor(Date.now() / 1000);
        const remainingTime = payload.exp - currentTime;
        
        return remainingTime > 0 ? remainingTime : -1;
    }
}

// 导出供其他模块使用
if (typeof module !== 'undefined' && module.exports) {
    module.exports = TokenManager;
}