package main

import (
	"bytes"
	"embed"
	"fmt"
	"io"
	"io/fs"
	"net"
	"net/http"
	"os"
	"strconv"
	"strings"
	"text/template"
	"time"

	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/bcrypt"
)

//go:embed static/*
var staticFS embed.FS

func SetupRouter() *gin.Engine {
	r := gin.Default()

	// 从 embed 读取前端静态文件
	staticSubFS, _ := fs.Sub(staticFS, "static")
	r.StaticFS("/static", http.FS(staticSubFS))

	// 根路由
	r.GET("/", func(c *gin.Context) {
		content, err := staticFS.ReadFile("static/index.html")
		if err != nil {
			c.String(500, "加载前端页面失败")
			return
		}
		c.Data(http.StatusOK, "text/html; charset=utf-8", content)
	})

	// 健康检查
	r.GET("/ping", func(c *gin.Context) {
		c.String(200, "frpc-console 后端已启动 🎉")
	})

	api := r.Group("/api")
	{
		// ---- 公开路由（不需要认证） ----
		api.GET("/check/users", checkUsersHandler)
		api.POST("/register", registerHandler)
		api.POST("/login", loginHandler)
		api.GET("/ping", pingHandler) // ← 移到这里

		// ---- 需要认证的路由 ----
		auth := api.Group("/")
		auth.Use(AuthMiddleware())
		{
			auth.GET("/config", getConfigHandler)
			auth.PUT("/config", updateConfigHandler)

			auth.GET("/proxies", getProxiesHandler)
			auth.GET("/proxy/:id", getProxyHandler)
			auth.POST("/proxy", createProxyHandler)
			auth.PUT("/proxy/:id", updateProxyHandler)
			auth.DELETE("/proxy/:id", deleteProxyHandler)

			auth.POST("/frpc/reload", reloadFrpcHandler)
			auth.POST("/frpc/start", startFrpcHandler)
			auth.POST("/frpc/stop", stopFrpcHandler)
			auth.GET("/frpc/status", getFrpcStatusHandler)
			auth.GET("/frpc/log", getFrpcLogHandler)

			auth.POST("/import/toml", importTomlHandler)
			auth.GET("/export/toml", ExportTomlHandler)

			auth.PUT("/user/password", changePasswordHandler)
		}
	}

	return r
}

// ========== 所有 Handler ==========

func checkUsersHandler(c *gin.Context) {
	count, err := CountUsers()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "查询用户失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": gin.H{"hasUsers": count > 0, "count": count},
	})
}

func registerHandler(c *gin.Context) {
	var req struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}

	count, err := CountUsers()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "查询用户失败"})
		return
	}
	if count > 0 {
		c.JSON(http.StatusForbidden, gin.H{"code": 1, "msg": "已存在管理员账户，请登录"})
		return
	}

	if len(req.Username) < 5 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "用户名至少 5 位"})
		return
	}

	if !ValidatePassword(req.Password) {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "密码至少 8 位，需包含大小写字母、数字和特殊字符"})
		return
	}

	hash, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "密码加密失败"})
		return
	}

	if err := CreateUser(req.Username, string(hash)); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "创建用户失败: " + err.Error()})
		return
	}

	token, err := GenerateJWT(req.Username)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成Token失败"})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"msg":  "注册成功",
		"data": gin.H{"token": token},
	})
}

// Ping 延迟检测
func pingHandler(c *gin.Context) {
	target := c.Query("target")
	if target == "" {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "缺少 target 参数"})
		return
	}

	// 获取全局配置（获取服务端端口）
	cfg, err := GetGlobalConfig()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取配置失败"})
		return
	}

	port := cfg.ServerPort
	address := net.JoinHostPort(target, strconv.Itoa(port))

	start := time.Now()
	conn, err := net.DialTimeout("tcp", address, 5*time.Second)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"code": 1, "msg": "ping 失败", "latency": -1})
		return
	}
	conn.Close()

	latency := time.Since(start).Milliseconds()
	c.JSON(http.StatusOK, gin.H{"code": 0, "latency": latency})
}

func loginHandler(c *gin.Context) {
	var req struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}

	user, err := GetUserByUsername(req.Username)
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"code": 1, "msg": "用户名或密码错误"})
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.Password)); err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"code": 1, "msg": "用户名或密码错误"})
		return
	}

	token, err := GenerateJWT(user.Username)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成Token失败"})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"msg":  "登录成功",
		"data": gin.H{"token": token},
	})
}

func changePasswordHandler(c *gin.Context) {
	var req struct {
		OldPassword string `json:"oldPassword"`
		NewPassword string `json:"newPassword"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}

	username, exists := c.Get("username")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"code": 1, "msg": "未登录"})
		return
	}

	user, err := GetUserByUsername(username.(string))
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"code": 1, "msg": "用户不存在"})
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.OldPassword)); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "当前密码错误"})
		return
	}

	if !ValidatePassword(req.NewPassword) {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "密码至少 8 位，需包含大小写字母、数字和特殊字符"})
		return
	}

	hash, err := bcrypt.GenerateFromPassword([]byte(req.NewPassword), bcrypt.DefaultCost)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "密码加密失败"})
		return
	}

	if err := UpdatePassword(username.(string), string(hash)); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "更新密码失败"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "密码修改成功"})
}

func getConfigHandler(c *gin.Context) {
	cfg, err := GetGlobalConfig()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取配置失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": cfg})
}

func updateConfigHandler(c *gin.Context) {
	var cfg GlobalConfig
	if err := c.ShouldBindJSON(&cfg); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}
	cfg.TcpMux = true

	if err := UpdateGlobalConfig(&cfg); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "更新配置失败: " + err.Error()})
		return
	}

	if err := GenerateFrpcConfig(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成配置文件失败: " + err.Error()})
		return
	}

	if err := ReloadFrpc(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "热加载失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "配置更新成功"})
}

func getProxiesHandler(c *gin.Context) {
	proxies, err := GetProxies()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取隧道列表失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": proxies})
}

func getProxyHandler(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "无效的ID"})
		return
	}
	p, err := GetProxy(id)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"code": 1, "msg": "隧道不存在"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": p})
}

func createProxyHandler(c *gin.Context) {
	var p Proxy
	if err := c.ShouldBindJSON(&p); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}
	p.Enabled = true

	if err := CreateProxy(&p); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "创建隧道失败: " + err.Error()})
		return
	}

	if err := generateAndReload(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "配置生效失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "隧道创建成功", "data": gin.H{"id": p.ID}})
}

func updateProxyHandler(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "无效的ID"})
		return
	}
	var p Proxy
	if err := c.ShouldBindJSON(&p); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请求参数错误"})
		return
	}
	p.ID = id

	if err := UpdateProxy(&p); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "更新隧道失败: " + err.Error()})
		return
	}

	if err := generateAndReload(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "配置生效失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "隧道更新成功"})
}

func deleteProxyHandler(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "无效的ID"})
		return
	}

	if err := DeleteProxy(id); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "删除隧道失败: " + err.Error()})
		return
	}

	if err := generateAndReload(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "配置生效失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "隧道删除成功"})
}

func reloadFrpcHandler(c *gin.Context) {
	if err := GenerateFrpcConfig(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成配置失败: " + err.Error()})
		return
	}
	if err := ReloadFrpc(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "热加载失败: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "热加载成功"})
}

func startFrpcHandler(c *gin.Context) {
	if err := StartFrpc(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "启动失败: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "frpc 启动成功"})
}

func stopFrpcHandler(c *gin.Context) {
	if err := StopFrpc(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "停止失败: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "frpc 已停止"})
}

func getFrpcStatusHandler(c *gin.Context) {
	running, err := GetFrpcStatus()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "查询状态失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": gin.H{"running": running}})
}

func importTomlHandler(c *gin.Context) {
	file, err := c.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "请选择文件"})
		return
	}

	f, err := file.Open()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取文件失败"})
		return
	}
	defer f.Close()

	buf := new(bytes.Buffer)
	if _, err := buf.ReadFrom(f); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取文件失败"})
		return
	}

	parsed, err := ParseToml(buf.String())
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 1, "msg": "解析 TOML 失败: " + err.Error()})
		return
	}

	cfg := parsed.ToGlobalConfig()
	cfg.TcpMux = true
	if err := UpdateGlobalConfig(cfg); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "更新配置失败: " + err.Error()})
		return
	}

	if _, err := DB.Exec("DELETE FROM proxies"); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "清空隧道失败"})
		return
	}

	proxies := parsed.ToProxies()
	for _, p := range proxies {
		if err := CreateProxy(&p); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "导入隧道失败: " + err.Error()})
			return
		}
	}

	if err := GenerateFrpcConfig(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成配置失败: " + err.Error()})
		return
	}

	if err := ReloadFrpc(); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code": 0,
			"msg":  fmt.Sprintf("导入成功！共 %d 条隧道，但热加载失败: %s", len(proxies), err.Error()),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"msg":  fmt.Sprintf("导入成功！共 %d 条隧道", len(proxies)),
	})
}

func ExportTomlHandler(c *gin.Context) {
	cfg, err := GetGlobalConfig()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取配置失败: " + err.Error()})
		return
	}

	proxies, err := GetProxies()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取隧道失败: " + err.Error()})
		return
	}

	var activeProxies []Proxy
	for _, p := range proxies {
		if p.Enabled {
			activeProxies = append(activeProxies, p)
		}
	}

	data := struct {
		*GlobalConfig
		Proxies []Proxy
	}{
		GlobalConfig: cfg,
		Proxies:      activeProxies,
	}

	tmpl, err := template.New("frpc").Parse(FrpcTemplateContent)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "解析模板失败: " + err.Error()})
		return
	}

	var buf bytes.Buffer
	if err := tmpl.Execute(&buf, data); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "渲染模板失败: " + err.Error()})
		return
	}

	c.Header("Content-Type", "text/plain; charset=utf-8")
	c.Header("Content-Disposition", "attachment; filename=frpc.toml")
	c.String(http.StatusOK, buf.String())
}

// ========== 日志读取 ==========

func getFrpcLogHandler(c *gin.Context) {
	// 读取 ./frpc.log，最多返回 200 行（最新的 200 行）
	lines, err := readTailLog("./frpc.log", 200)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code": 0,
			"data": gin.H{
				"lines": []string{},
				"total": 0,
				"error": err.Error(),
			},
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": gin.H{
			"lines": lines,
			"total": len(lines),
		},
	})
}

// readTailLog 读取文件末尾 n 行（倒序读取，返回正序）
func readTailLog(filePath string, n int) ([]string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	// 获取文件大小
	info, err := file.Stat()
	if err != nil {
		return nil, err
	}
	fileSize := info.Size()
	if fileSize == 0 {
		return []string{}, nil
	}

	// 从末尾开始读
	const chunkSize = 4096
	var lines []string
	var leftover []byte
	offset := fileSize

	for len(lines) < n && offset > 0 {
		// 计算读取起点
		readSize := chunkSize
		if offset < int64(chunkSize) {
			readSize = int(offset)
		}
		offset -= int64(readSize)

		// 读取这一块
		buf := make([]byte, readSize)
		_, err := file.ReadAt(buf, offset)
		if err != nil && err != io.EOF {
			return nil, err
		}

		// 将当前块与之前剩下的拼接
		data := append(buf, leftover...)
		leftover = nil

		// 按行分割
		start := 0
		for i := len(data) - 1; i >= 0; i-- {
			if data[i] == '\n' {
				if i+1 < len(data) {
					line := string(data[i+1:])
					if line != "" {
						lines = append([]string{line}, lines...)
						if len(lines) >= n {
							break
						}
					}
				}
				start = i
			}
		}

		// 如果还没凑够，把未处理的部分留到下一轮
		if len(lines) < n && start > 0 {
			leftover = data[:start]
		}
	}

	// 处理最后剩余部分（文件开头）
	if len(lines) < n && len(leftover) > 0 {
		// 从 leftover 中提取行
		parts := strings.Split(string(leftover), "\n")
		for i := len(parts) - 1; i >= 0; i-- {
			if parts[i] != "" {
				lines = append([]string{parts[i]}, lines...)
				if len(lines) >= n {
					break
				}
			}
		}
	}

	return lines, nil
}

func generateAndReload() error {
	if err := GenerateFrpcConfig(); err != nil {
		return err
	}
	return ReloadFrpc()
}