package core

import (
	"context"
	"crypto/tls"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/url"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"time"

	"clash-speed-test/internal/config"
	"clash-speed-test/internal/database"
	applogger "clash-speed-test/internal/logger"
)

type SpeedTester struct {
	config      *config.Config
	testURLs    []string
	timeout     time.Duration
	concurrency int
	httpClient  *http.Client
}

type SpeedTestResult struct {
	Latency       int     `json:"latency"`
	DownloadSpeed float64 `json:"download_speed"` // Mbps
	UploadSpeed   float64 `json:"upload_speed"`   // Mbps
	IPAddress     string  `json:"ip_address"`
	Location      string  `json:"location"`
	Success       bool    `json:"success"`
	ErrorMessage  string  `json:"error_message"`
}

func NewSpeedTester(cfg *config.Config) *SpeedTester {
	// 创建HTTP客户端
	httpClient := &http.Client{
		Timeout: cfg.Speed.Timeout,
		Transport: &http.Transport{
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: false,
			},
			DisableKeepAlives: true,
			MaxIdleConns:      100,
			IdleConnTimeout:   30 * time.Second,
		},
	}

	return &SpeedTester{
		config:      cfg,
		testURLs:    cfg.Speed.TestURLs,
		timeout:     cfg.Speed.Timeout,
		concurrency: cfg.Speed.Concurrency,
		httpClient:  httpClient,
	}
}

// 测试单个节点
func (st *SpeedTester) TestNode(node database.Node) (*database.TestResult, error) {
	startTime := time.Now()
	
	result := &database.TestResult{
		NodeID:    node.ID,
		TestTime:  time.Now(),
		IsSuccess: false,
	}

	applogger.Info("开始测试节点", map[string]interface{}{
		"name": node.Name,
		"type": node.Type,
		"server": node.Server,
		"port": node.Port,
	})

	// 验证节点配置的有效性
	if err := st.validateNode(node); err != nil {
		result.ErrorMessage = fmt.Sprintf("节点配置无效: %v", err)
		applogger.Warn("节点配置无效", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
		return result, nil
	}

	// 测试连接性和速度
	speedResult, err := st.testNodeSpeed(node)
	if err != nil {
		result.ErrorMessage = fmt.Sprintf("测速失败: %v", err)
		applogger.Warn("节点测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	} else if speedResult.Success {
		result.IsSuccess = true
		result.Latency = &speedResult.Latency
		result.IPAddress = speedResult.IPAddress
		result.Location = speedResult.Location
		result.TestURL = st.testURLs[0]

		// 如果有速度数据，保存到扩展字段
		if speedResult.DownloadSpeed > 0 {
			downloadSpeed := int(speedResult.DownloadSpeed)
			result.DownloadSpeed = &downloadSpeed
		}
		if speedResult.UploadSpeed > 0 {
			uploadSpeed := int(speedResult.UploadSpeed)
			result.UploadSpeed = &uploadSpeed
		}

		applogger.Info("节点测试成功", map[string]interface{}{
			"node":           node.Name,
			"latency":        speedResult.Latency,
			"download_speed": speedResult.DownloadSpeed,
			"upload_speed":   speedResult.UploadSpeed,
			"ip":             speedResult.IPAddress,
			"location":       speedResult.Location,
		})
	} else {
		result.ErrorMessage = speedResult.ErrorMessage
		applogger.Warn("节点测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": speedResult.ErrorMessage,
		})
	}

	// 计算测试时长
	duration := int(time.Since(startTime).Milliseconds())
	result.TestDuration = &duration

	// 保存测试结果
	if err := database.SaveTestResult(result); err != nil {
		applogger.Error("保存测试结果失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	}

	return result, nil
}

// 验证节点配置的有效性
func (st *SpeedTester) validateNode(node database.Node) error {
	// 检查必需的字段
	if node.Name == "" {
		return fmt.Errorf("节点名称不能为空")
	}
	
	if node.Type == "" {
		return fmt.Errorf("节点类型不能为空")
	}
	
	if node.Server == "" {
		return fmt.Errorf("服务器地址不能为空")
	}
	
	if node.Port <= 0 || node.Port > 65535 {
		return fmt.Errorf("端口号无效: %d", node.Port)
	}

	// 验证server字段是否为有效的域名或IP地址
	server := strings.TrimSpace(node.Server)
	
	// 只检查明显无效的情况，而不是过于严格的验证
	// 检查是否包含中文字符（通常表示这是描述而不是有效地址）
	for _, r := range server {
		if r >= 0x4e00 && r <= 0x9fff {
			return fmt.Errorf("服务器地址包含中文字符，无效: %s", server)
		}
	}
	
	// 检查是否是URL格式（不应该作为server地址）
	if strings.HasPrefix(server, "http://") || strings.HasPrefix(server, "https://") {
		return fmt.Errorf("服务器地址不能是URL格式: %s", server)
	}
	
	// 检查是否包含明显的无效字符（如空格、特殊符号等）
	invalidChars := regexp.MustCompile(`[<>:"\\|?*]`)
	if invalidChars.MatchString(server) {
		return fmt.Errorf("服务器地址包含无效字符: %s", server)
	}
	
	// 检查是否为空或只包含空白字符
	if server == "" {
		return fmt.Errorf("服务器地址不能为空")
	}

	// 对于SS/SSR节点，检查密码
	if (node.Type == "ss" || node.Type == "ssr") && node.Password == "" {
		return fmt.Errorf("SS/SSR节点必须设置密码")
	}

	// 对于Vmess节点，检查UUID
	if node.Type == "vmess" && node.UUID == "" {
		return fmt.Errorf("Vmess节点必须设置UUID")
	}

	// 对于Trojan节点，检查密码
	if node.Type == "trojan" && node.Password == "" {
		return fmt.Errorf("Trojan节点必须设置密码")
	}

	return nil
}

// 批量测试节点
func (st *SpeedTester) TestNodes(nodes []database.Node) []*database.TestResult {
	var results []*database.TestResult
	var mu sync.Mutex
	var wg sync.WaitGroup

	// 创建信号量控制并发数
	semaphore := make(chan struct{}, st.concurrency)

	for _, node := range nodes {
		wg.Add(1)
		go func(n database.Node) {
			defer wg.Done()
			
			// 获取信号量
			semaphore <- struct{}{}
			defer func() { <-semaphore }()

			result, err := st.TestNode(n)
			if err != nil {
							applogger.Error("节点测试异常", map[string]interface{}{
				"node":  n.Name,
				"error": err.Error(),
			})
				return
			}

			mu.Lock()
			results = append(results, result)
			mu.Unlock()
		}(node)
	}

	wg.Wait()
	return results
}

// 测试节点速度
func (st *SpeedTester) testNodeSpeed(node database.Node) (*SpeedTestResult, error) {
	result := &SpeedTestResult{
		Success: false,
	}

	// 根据代理类型选择测试策略
	switch node.Type {
	case "http", "https":
		return st.testHTTPProxy(node)
	case "socks5":
		return st.testSOCKS5Proxy(node)
	case "ss", "ssr", "vmess", "trojan":
		// 对于高级代理，尝试多种测试方法
		return st.testAdvancedProxy(node)
	default:
		return result, fmt.Errorf("暂不支持代理类型: %s", node.Type)
	}
}

// 测试HTTP代理
func (st *SpeedTester) testHTTPProxy(node database.Node) (*SpeedTestResult, error) {
	result := &SpeedTestResult{}

	// 构建代理URL
	proxyURL := fmt.Sprintf("http://%s:%d", node.Server, node.Port)
	if node.Username != "" && node.Password != "" {
		proxyURL = fmt.Sprintf("http://%s:%s@%s:%d", node.Username, node.Password, node.Server, node.Port)
	}

	// 创建代理客户端
	proxyURLParsed, err := url.Parse(proxyURL)
	if err != nil {
		return result, fmt.Errorf("解析代理URL失败: %w", err)
	}

	proxyClient := &http.Client{
		Timeout: st.timeout,
		Transport: &http.Transport{
			Proxy: http.ProxyURL(proxyURLParsed),
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: false,
			},
			DisableKeepAlives: true,
		},
	}

	// 测试延迟
	latency, ipAddress, location, err := st.testLatency(proxyClient)
	if err != nil {
		return result, fmt.Errorf("延迟测试失败: %w", err)
	}

	result.Latency = latency
	result.IPAddress = ipAddress
	result.Location = location

	// 测试下载速度
	downloadSpeed, err := st.testDownloadSpeed(proxyClient)
	if err != nil {
		applogger.Warn("下载速度测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	} else {
		result.DownloadSpeed = downloadSpeed
	}

	// 测试上传速度
	uploadSpeed, err := st.testUploadSpeed(proxyClient)
	if err != nil {
		applogger.Warn("上传速度测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	} else {
		result.UploadSpeed = uploadSpeed
	}

	result.Success = true
	return result, nil
}

// 测试SOCKS5代理
func (st *SpeedTester) testSOCKS5Proxy(node database.Node) (*SpeedTestResult, error) {
	result := &SpeedTestResult{}

	// 构建SOCKS5代理URL
	proxyURL := fmt.Sprintf("socks5://%s:%d", node.Server, node.Port)
	if node.Username != "" && node.Password != "" {
		proxyURL = fmt.Sprintf("socks5://%s:%s@%s:%d", node.Username, node.Password, node.Server, node.Port)
	}

	// 创建代理客户端
	proxyURLParsed, err := url.Parse(proxyURL)
	if err != nil {
		return result, fmt.Errorf("解析SOCKS5代理URL失败: %w", err)
	}

	proxyClient := &http.Client{
		Timeout: st.timeout,
		Transport: &http.Transport{
			Proxy: http.ProxyURL(proxyURLParsed),
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: false,
			},
			DisableKeepAlives: true,
		},
	}

	// 测试延迟
	latency, ipAddress, location, err := st.testLatency(proxyClient)
	if err != nil {
		return result, fmt.Errorf("延迟测试失败: %w", err)
	}

	result.Latency = latency
	result.IPAddress = ipAddress
	result.Location = location

	// 测试下载速度
	downloadSpeed, err := st.testDownloadSpeed(proxyClient)
	if err != nil {
		applogger.Warn("下载速度测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	} else {
		result.DownloadSpeed = downloadSpeed
	}

	// 测试上传速度
	uploadSpeed, err := st.testUploadSpeed(proxyClient)
	if err != nil {
		applogger.Warn("上传速度测试失败", map[string]interface{}{
			"node":  node.Name,
			"error": err.Error(),
		})
	} else {
		result.UploadSpeed = uploadSpeed
	}

	result.Success = true
	return result, nil
}

// 测试高级代理（Shadowsocks、Vmess等）
func (st *SpeedTester) testAdvancedProxy(node database.Node) (*SpeedTestResult, error) {
	result := &SpeedTestResult{}

	// 对于高级代理，我们需要通过本地Clash代理来测试
	// 但首先需要验证本地代理是否可用，以及是否真的配置了这个节点

	// 对于高级代理，我们尝试通过本地代理端口进行测试
	// 如果本地代理不可用，会在测试过程中失败，这是正常的

	// 尝试常见的本地代理端口
	localProxyPorts := []int{7890, 7891, 1080, 8080, 8118}
	
	for _, port := range localProxyPorts {
		proxyURL := fmt.Sprintf("http://127.0.0.1:%d", port)
		proxyURLParsed, err := url.Parse(proxyURL)
		if err != nil {
			continue
		}

		proxyClient := &http.Client{
			Timeout: st.timeout,
			Transport: &http.Transport{
				Proxy: http.ProxyURL(proxyURLParsed),
				TLSClientConfig: &tls.Config{
					InsecureSkipVerify: false,
				},
				DisableKeepAlives: true,
			},
		}

		// 测试延迟
		latency, ipAddress, location, err := st.testLatency(proxyClient)
		if err == nil {
			result.Latency = latency
			result.IPAddress = ipAddress
			result.Location = location
			result.Success = true

			// 测试下载速度
			if downloadSpeed, err := st.testDownloadSpeed(proxyClient); err == nil {
				result.DownloadSpeed = downloadSpeed
			}

			// 测试上传速度
			if uploadSpeed, err := st.testUploadSpeed(proxyClient); err == nil {
				result.UploadSpeed = uploadSpeed
			}

			applogger.Info("通过本地代理测试成功", map[string]interface{}{
				"node": node.Name,
				"port": port,
			})

			return result, nil
		}
	}

	return result, fmt.Errorf("无法通过本地代理测试节点: %s", node.Name)
}

// 测试延迟
func (st *SpeedTester) testLatency(client *http.Client) (int, string, string, error) {
	startTime := time.Now()

	// 尝试多个测试URL
	for _, testURL := range st.testURLs {
		req, err := http.NewRequest("HEAD", testURL, nil)
		if err != nil {
			continue
		}

		req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")

		resp, err := client.Do(req)
		if err != nil {
			continue
		}
		defer resp.Body.Close()

		latency := int(time.Since(startTime).Milliseconds())
		ipAddress := st.extractIPAddress(resp)
		location := st.extractLocation(resp)

		return latency, ipAddress, location, nil
	}

	return 0, "", "", fmt.Errorf("所有测试URL都无法访问")
}

// 测试下载速度
func (st *SpeedTester) testDownloadSpeed(client *http.Client) (float64, error) {
	// 使用1MB的测试文件
	testURL := "https://httpbin.org/bytes/1048576"
	
	startTime := time.Now()
	
	req, err := http.NewRequest("GET", testURL, nil)
	if err != nil {
		return 0, fmt.Errorf("创建请求失败: %w", err)
	}

	resp, err := client.Do(req)
	if err != nil {
		return 0, fmt.Errorf("下载测试失败: %w", err)
	}
	defer resp.Body.Close()

	// 读取响应体
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return 0, fmt.Errorf("读取响应失败: %w", err)
	}

	duration := time.Since(startTime).Seconds()
	fileSize := len(body)

	// 计算下载速度 (Mbps)
	speedBps := float64(fileSize) / duration
	speedMbps := (speedBps * 8) / (1024 * 1024)

	return speedMbps, nil
}

// 测试上传速度
func (st *SpeedTester) testUploadSpeed(client *http.Client) (float64, error) {
	// 使用1MB的测试数据
	testData := strings.Repeat("A", 1024*1024)
	
	startTime := time.Now()
	
	req, err := http.NewRequest("POST", "https://httpbin.org/post", strings.NewReader(testData))
	if err != nil {
		return 0, fmt.Errorf("创建请求失败: %w", err)
	}

	req.Header.Set("Content-Type", "application/octet-stream")

	resp, err := client.Do(req)
	if err != nil {
		return 0, fmt.Errorf("上传测试失败: %w", err)
	}
	defer resp.Body.Close()

	duration := time.Since(startTime).Seconds()
	fileSize := len(testData)

	// 计算上传速度 (Mbps)
	speedBps := float64(fileSize) / duration
	speedMbps := (speedBps * 8) / (1024 * 1024)

	return speedMbps, nil
}

// 提取IP地址
func (st *SpeedTester) extractIPAddress(resp *http.Response) string {
	if ip := resp.Header.Get("X-Forwarded-For"); ip != "" {
		return strings.Split(ip, ",")[0]
	}
	if ip := resp.Header.Get("X-Real-IP"); ip != "" {
		return ip
	}
	if ip := resp.Header.Get("CF-Connecting-IP"); ip != "" {
		return ip
	}
	return "unknown"
}

// 提取位置信息
func (st *SpeedTester) extractLocation(resp *http.Response) string {
	if resp.Header.Get("CF-Ray") != "" {
		return "Cloudflare"
	}
	if country := resp.Header.Get("CF-IPCountry"); country != "" {
		return country
	}
	return "unknown"
}