package main

import (
	"embed"
	"fmt"
	"github.com/gin-gonic/gin"
	"io"
	"net/http"
	"regexp"
	"strconv"
	"strings"
)

//go:embed public/*
var staticFiles embed.FS

// 服务嵌入的静态文件
func serveEmbedFile(c *gin.Context, filename string) {
	data, err := staticFiles.ReadFile(filename)
	if err != nil {
		c.Status(404)
		return
	}
	contentType := "text/html; charset=utf-8"
	if strings.HasSuffix(filename, ".ico") {
		contentType = "image/x-icon"
	}
	c.Data(200, contentType, data)
}

var (
	exps = []*regexp.Regexp{
		regexp.MustCompile(`^(?:https?://)?github\.com/([^/]+)/([^/]+)/(?:releases|archive)/.*$`),
		regexp.MustCompile(`^(?:https?://)?github\.com/([^/]+)/([^/]+)/(?:blob|raw)/.*$`),
		regexp.MustCompile(`^(?:https?://)?github\.com/([^/]+)/([^/]+)/(?:info|git-).*$`),
		regexp.MustCompile(`^(?:https?://)?raw\.github(?:usercontent|)\.com/([^/]+)/([^/]+)/.+?/.+$`),
		regexp.MustCompile(`^(?:https?://)?gist\.github(?:usercontent|)\.com/([^/]+)/.+?/.+`),
		regexp.MustCompile(`^(?:https?://)?api\.github\.com/repos/([^/]+)/([^/]+)/.*`),
		regexp.MustCompile(`^(?:https?://)?huggingface\.co(?:/spaces)?/([^/]+)/(.+)$`),
		regexp.MustCompile(`^(?:https?://)?cdn-lfs\.hf\.co(?:/spaces)?/([^/]+)/([^/]+)(?:/(.*))?$`),
		regexp.MustCompile(`^(?:https?://)?download\.docker\.com/([^/]+)/.*\.(tgz|zip)$`),
		regexp.MustCompile(`^(?:https?://)?(github|opengraph)\.githubassets\.com/([^/]+)/.+?$`),
	}
	globalLimiter *IPRateLimiter
)

func main() {
	// 加载配置
	if err := LoadConfig(); err != nil {
		fmt.Printf("配置加载失败: %v\n", err)
		return
	}
	
	// 初始化HTTP客户端
	initHTTPClients()
	
	// 初始化限流器
	initLimiter()
	
	// 初始化Docker流式代理
	initDockerProxy()

	gin.SetMode(gin.ReleaseMode)
	router := gin.Default()

	// 初始化skopeo路由（静态文件和API路由）
	initSkopeoRoutes(router)
	
	// 静态文件路由（使用嵌入文件）
	router.GET("/", func(c *gin.Context) {
		serveEmbedFile(c, "public/index.html")
	})
	router.GET("/public/*filepath", func(c *gin.Context) {
		filepath := strings.TrimPrefix(c.Param("filepath"), "/")
		serveEmbedFile(c, "public/"+filepath)
	})
	router.GET("/skopeo.html", func(c *gin.Context) {
		serveEmbedFile(c, "public/skopeo.html")
	})
	router.GET("/search.html", func(c *gin.Context) {
		serveEmbedFile(c, "public/search.html")
	})
	router.GET("/favicon.ico", func(c *gin.Context) {
		serveEmbedFile(c, "public/favicon.ico")
	})

	// 注册dockerhub搜索路由
	RegisterSearchRoute(router)
	
	// 注册Docker认证路由（/token*）
	router.Any("/token", RateLimitMiddleware(globalLimiter), ProxyDockerAuthGin)
	router.Any("/token/*path", RateLimitMiddleware(globalLimiter), ProxyDockerAuthGin)
	
	// 注册Docker Registry代理路由
	router.Any("/v2/*path", RateLimitMiddleware(globalLimiter), ProxyDockerRegistryGin)
	

	// 注册NoRoute处理器，应用限流中间件
	router.NoRoute(RateLimitMiddleware(globalLimiter), handler)

	cfg := GetConfig()
	fmt.Printf("启动成功，项目地址：https://github.com/sky22333/hubproxy \n")
	
	err := router.Run(fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port))
	if err != nil {
		fmt.Printf("启动服务失败: %v\n", err)
	}
}

func handler(c *gin.Context) {
	rawPath := strings.TrimPrefix(c.Request.URL.RequestURI(), "/")

	for strings.HasPrefix(rawPath, "/") {
		rawPath = strings.TrimPrefix(rawPath, "/")
	}

	if !strings.HasPrefix(rawPath, "http") {
		c.String(http.StatusForbidden, "无效输入")
		return
	}

	matches := checkURL(rawPath)
	if matches != nil {
		// GitHub仓库访问控制检查
		if allowed, reason := GlobalAccessController.CheckGitHubAccess(matches); !allowed {
			// 构建仓库名用于日志
			var repoPath string
			if len(matches) >= 2 {
				username := matches[0]
				repoName := strings.TrimSuffix(matches[1], ".git")
				repoPath = username + "/" + repoName
			}
			fmt.Printf("GitHub仓库 %s 访问被拒绝: %s\n", repoPath, reason)
			c.String(http.StatusForbidden, reason)
			return
		}
	} else {
		c.String(http.StatusForbidden, "无效输入")
		return
	}

	if exps[1].MatchString(rawPath) {
		rawPath = strings.Replace(rawPath, "/blob/", "/raw/", 1)
	}

	proxy(c, rawPath)
}


func proxy(c *gin.Context, u string) {
	proxyWithRedirect(c, u, 0)
}


func proxyWithRedirect(c *gin.Context, u string, redirectCount int) {
	// 限制最大重定向次数，防止无限递归
	const maxRedirects = 20
	if redirectCount > maxRedirects {
		c.String(http.StatusLoopDetected, "重定向次数过多，可能存在循环重定向")
		return
	}
	req, err := http.NewRequest(c.Request.Method, u, c.Request.Body)
	if err != nil {
		c.String(http.StatusInternalServerError, fmt.Sprintf("server error %v", err))
		return
	}

	for key, values := range c.Request.Header {
		for _, value := range values {
			req.Header.Add(key, value)
		}
	}
	req.Header.Del("Host")

	resp, err := GetGlobalHTTPClient().Do(req)
	if err != nil {
		c.String(http.StatusInternalServerError, fmt.Sprintf("server error %v", err))
		return
	}
	defer func() {
		if err := resp.Body.Close(); err != nil {
			fmt.Printf("关闭响应体失败: %v\n", err)
		}
	}()

	// 检查文件大小限制
	cfg := GetConfig()
	if contentLength := resp.Header.Get("Content-Length"); contentLength != "" {
		if size, err := strconv.ParseInt(contentLength, 10, 64); err == nil && size > cfg.Server.FileSize {
			c.String(http.StatusRequestEntityTooLarge, 
				fmt.Sprintf("文件过大，限制大小: %d MB", cfg.Server.FileSize/(1024*1024)))
			return
		}
	}

	// 清理安全相关的头
	resp.Header.Del("Content-Security-Policy")
	resp.Header.Del("Referrer-Policy")
	resp.Header.Del("Strict-Transport-Security")
	
	// 智能处理系统 - 自动识别需要加速的内容
	// 获取真实域名
	realHost := c.Request.Header.Get("X-Forwarded-Host")
	if realHost == "" {
		realHost = c.Request.Host
	}
	// 如果域名中没有协议前缀，添加https://
	if !strings.HasPrefix(realHost, "http://") && !strings.HasPrefix(realHost, "https://") {
		realHost = "https://" + realHost
	}

	// 🚀 高性能预筛选：仅对.sh文件进行智能处理
	if strings.HasSuffix(strings.ToLower(u), ".sh") {
		// 检查是否为gzip压缩内容
		isGzipCompressed := resp.Header.Get("Content-Encoding") == "gzip"
		
		// 仅对shell脚本使用智能处理器
		processedBody, processedSize, err := ProcessSmart(resp.Body, isGzipCompressed, realHost)
		if err != nil {
			// 优雅降级 - 处理失败时使用直接代理模式
			fmt.Printf("智能处理失败，回退到直接代理: %v\n", err)
			processedBody = resp.Body
			processedSize = 0
		}

		// 智能设置响应头
		if processedSize > 0 {
			// 内容被处理过，清理压缩相关头，使用chunked传输
			resp.Header.Del("Content-Length")
			resp.Header.Del("Content-Encoding")
			resp.Header.Set("Transfer-Encoding", "chunked")
		}

		// 复制其他响应头
		for key, values := range resp.Header {
			for _, value := range values {
				c.Header(key, value)
			}
		}

		if location := resp.Header.Get("Location"); location != "" {
			if checkURL(location) != nil {
				c.Header("Location", "/"+location)
			} else {
				proxyWithRedirect(c, location, redirectCount+1)
				return
			}
		}

		c.Status(resp.StatusCode)

		// 输出处理后的内容
		if _, err := io.Copy(c.Writer, processedBody); err != nil {
			return
		}
	} else {
		// 🔥 非.sh文件：直接高性能流式代理，零内存消耗
		// 复制所有响应头
		for key, values := range resp.Header {
			for _, value := range values {
				c.Header(key, value)
			}
		}

		// 处理重定向
		if location := resp.Header.Get("Location"); location != "" {
			if checkURL(location) != nil {
				c.Header("Location", "/"+location)
			} else {
				proxyWithRedirect(c, location, redirectCount+1)
				return
			}
		}

		c.Status(resp.StatusCode)

		// 直接流式转发，零内存拷贝
		if _, err := io.Copy(c.Writer, resp.Body); err != nil {
			fmt.Printf("直接代理失败: %v\n", err)
		}
	}
}

func checkURL(u string) []string {
	for _, exp := range exps {
		if matches := exp.FindStringSubmatch(u); matches != nil {
			return matches[1:]
		}
	}
	return nil
}