/**
 * 设备指纹生成工具
 * 通过收集浏览器和设备特征生成唯一标识
 */

class DeviceFingerprint {
    constructor() {
        this.components = [];
    }

    /**
     * 收集所有设备特征
     */
    async collectComponents() {
        this.components = [];

        // 1. User Agent
        this.addComponent('userAgent', navigator.userAgent);

        // 2. 语言
        this.addComponent('language', navigator.language);

        // 3. 屏幕分辨率
        this.addComponent('screenResolution', `${screen.width}x${screen.height}x${screen.colorDepth}`);

        // 4. 时区
        this.addComponent('timezone', Intl.DateTimeFormat().resolvedOptions().timeZone);
        this.addComponent('timezoneOffset', new Date().getTimezoneOffset());

        // 5. 平台
        this.addComponent('platform', navigator.platform);

        // 6. Canvas指纹
        this.addComponent('canvas', await this.getCanvasFingerprint());

        // 7. WebGL指纹
        this.addComponent('webgl', this.getWebGLFingerprint());

        // 8. 字体检测
        this.addComponent('fonts', this.getAvailableFonts());

        // 9. 插件信息
        this.addComponent('plugins', this.getPluginInfo());

        // 10. 硬件并发数
        this.addComponent('hardwareConcurrency', navigator.hardwareConcurrency || 'unknown');

        // 11. 设备内存
        this.addComponent('deviceMemory', navigator.deviceMemory || 'unknown');

        // 12. 触摸支持
        this.addComponent('touchSupport', 'ontouchstart' in window);

        // 13. Cookie启用
        this.addComponent('cookieEnabled', navigator.cookieEnabled);

        // 14. Do Not Track
        this.addComponent('doNotTrack', navigator.doNotTrack || 'unknown');
    }

    /**
     * 添加组件
     */
    addComponent(key, value) {
        this.components.push({ key, value });
    }

    /**
     * 获取Canvas指纹
     */
    async getCanvasFingerprint() {
        try {
            const canvas = document.createElement('canvas');
            const ctx = canvas.getContext('2d');
            
            canvas.width = 200;
            canvas.height = 50;
            
            // 绘制文本
            ctx.textBaseline = 'top';
            ctx.font = '14px Arial';
            ctx.fillStyle = '#f60';
            ctx.fillRect(0, 0, 200, 50);
            ctx.fillStyle = '#069';
            ctx.fillText('Device Fingerprint 🔒', 10, 10);
            
            // 获取图像数据
            return canvas.toDataURL();
        } catch (e) {
            return 'unsupported';
        }
    }

    /**
     * 获取WebGL指纹
     */
    getWebGLFingerprint() {
        try {
            const canvas = document.createElement('canvas');
            const gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
            
            if (!gl) return 'unsupported';
            
            const debugInfo = gl.getExtension('WEBGL_debug_renderer_info');
            if (!debugInfo) return 'no-extension';
            
            const vendor = gl.getParameter(debugInfo.UNMASKED_VENDOR_WEBGL);
            const renderer = gl.getParameter(debugInfo.UNMASKED_RENDERER_WEBGL);
            
            return `${vendor}~${renderer}`;
        } catch (e) {
            return 'unsupported';
        }
    }

    /**
     * 检测可用字体
     */
    getAvailableFonts() {
        const baseFonts = ['monospace', 'sans-serif', 'serif'];
        const testFonts = [
            'Arial', 'Verdana', 'Times New Roman', 'Courier New',
            'Georgia', 'Palatino', 'Garamond', 'Comic Sans MS',
            'Trebuchet MS', 'Impact', 'Arial Black', 'Tahoma'
        ];
        
        const availableFonts = [];
        
        // 创建测试元素
        const testString = 'mmmmmmmmmmlli';
        const testSize = '72px';
        const canvas = document.createElement('canvas');
        const ctx = canvas.getContext('2d');
        
        // 获取基准字体宽度
        const baseFontWidths = {};
        baseFonts.forEach(baseFont => {
            ctx.font = `${testSize} ${baseFont}`;
            baseFontWidths[baseFont] = ctx.measureText(testString).width;
        });
        
        // 测试每个字体
        testFonts.forEach(font => {
            let detected = false;
            baseFonts.forEach(baseFont => {
                ctx.font = `${testSize} '${font}', ${baseFont}`;
                const width = ctx.measureText(testString).width;
                if (width !== baseFontWidths[baseFont]) {
                    detected = true;
                }
            });
            if (detected) {
                availableFonts.push(font);
            }
        });
        
        return availableFonts.join(',');
    }

    /**
     * 获取插件信息
     */
    getPluginInfo() {
        if (!navigator.plugins) return 'unsupported';
        
        const plugins = [];
        for (let i = 0; i < navigator.plugins.length; i++) {
            plugins.push(navigator.plugins[i].name);
        }
        return plugins.join(',');
    }

    /**
     * 生成指纹哈希
     */
    async generateHash() {
        await this.collectComponents();
        
        // 将所有组件转换为字符串
        const componentString = this.components
            .map(c => `${c.key}:${c.value}`)
            .join('|');
        
        // 使用简单的哈希函数（生产环境建议使用更强的哈希）
        return this.simpleHash(componentString);
    }

    /**
     * 简单哈希函数
     */
    simpleHash(str) {
        let hash = 0;
        for (let i = 0; i < str.length; i++) {
            const char = str.charCodeAt(i);
            hash = ((hash << 5) - hash) + char;
            hash = hash & hash; // Convert to 32bit integer
        }
        return Math.abs(hash).toString(16);
    }

    /**
     * 获取或创建设备指纹
     */
    static async getFingerprint() {
        try {
            // 尝试从localStorage获取缓存的指纹
            const cached = localStorage.getItem('device_fingerprint');
            if (cached) {
                return cached;
            }
        } catch (e) {
            console.warn('读取缓存的设备指纹失败:', e);
        }
        
        try {
            // 生成新指纹
            const fp = new DeviceFingerprint();
            const fingerprint = await fp.generateHash();
            
            // 尝试缓存指纹
            try {
                localStorage.setItem('device_fingerprint', fingerprint);
            } catch (e) {
                console.warn('缓存设备指纹失败:', e);
            }
            
            return fingerprint;
        } catch (error) {
            console.error('生成设备指纹失败:', error);
            // 降级方案：返回基于UserAgent的简单hash
            const fallback = new DeviceFingerprint();
            return fallback.simpleHash(navigator.userAgent + Date.now());
        }
    }

    /**
     * 清除缓存的指纹
     */
    static clearFingerprint() {
        localStorage.removeItem('device_fingerprint');
    }
}

// 导出供其他脚本使用
if (typeof module !== 'undefined' && module.exports) {
    module.exports = DeviceFingerprint;
}