package main

import (
	"bytes"
	"embed"
	"encoding/json"
	"io"
	"io/fs" // 新增
	"net/http"
	"os"
	"strings"
	"text/template"

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

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

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

	staticSubFS, _ := fs.Sub(staticFS, "static")
	r.StaticFS("/static", http.FS(staticSubFS))

	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)
	})

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

	api := r.Group("/api")
	{
		api.GET("/check/users", checkUsersHandler)
		api.POST("/register", registerHandler)
		api.POST("/login", loginHandler)

		auth := api.Group("/")
		auth.Use(AuthMiddleware())
		{
			auth.GET("/config", getConfigHandler)
			auth.PUT("/config", updateConfigHandler)

			auth.GET("/frps/log", getFrpsLogHandler)

			// frps 特有：客户端列表（从 Dashboard API 读取）
			auth.GET("/clients", getClientsHandler)
			auth.GET("/proxies", getProxiesHandler)

			auth.POST("/frps/reload", reloadFrpsHandler)
			auth.POST("/frps/start", startFrpsHandler)
			auth.POST("/frps/stop", stopFrpsHandler)
			auth.GET("/frps/status", getFrpsStatusHandler)

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

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

	return r
}

// ============================================================
// 认证 Handler（与 frpc-console 相同，略）
// ============================================================

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},
	})
}

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"})
}

// ============================================================
// 配置 Handler
// ============================================================

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
	}

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

	if err := ReloadFrps(); 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"})
}

// ============================================================
// 客户端/代理列表（从 frps Dashboard API 读取）
// ============================================================

// FrpsDashboardClient frps Dashboard API 返回的客户端信息
type FrpsDashboardClient struct {
	ID       int    `json:"id"`
	Name     string `json:"name"`
	OS       string `json:"os"`
	Arch     string `json:"arch"`
	Version  string `json:"version"`
	Status   string `json:"status"`
	ConnTime string `json:"connTime"`
}

// FrpsDashboardProxy frps Dashboard API 返回的代理信息
type FrpsDashboardProxy struct {
	Name       string `json:"name"`
	Type       string `json:"type"`
	Status     string `json:"status"`
	LocalAddr  string `json:"localAddr"`
	RemoteAddr string `json:"remoteAddr"`
}

func getClientsHandler(c *gin.Context) {
	clients, err := fetchClientsFromDashboard()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"code": 0, "data": []interface{}{}, "msg": "无法连接 frps Dashboard: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": clients})
}

func getProxiesHandler(c *gin.Context) {
	proxies, err := fetchProxiesFromDashboard()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"code": 0, "data": []interface{}{}, "msg": "无法连接 frps Dashboard: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": proxies})
}

// fetchClientsFromDashboard 从 frps Dashboard API 读取客户端列表
func fetchClientsFromDashboard() ([]FrpsDashboardClient, error) {
	// frps Dashboard 默认在 127.0.0.1:7500，后续可配置
	resp, err := http.Get("http://127.0.0.1:7500/api/v2/clients")
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	var result struct {
		Data []FrpsDashboardClient `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, err
	}
	return result.Data, nil
}

// fetchProxiesFromDashboard 从 frps Dashboard API 读取代理列表
func fetchProxiesFromDashboard() ([]FrpsDashboardProxy, error) {
	resp, err := http.Get("http://127.0.0.1:7500/api/v2/proxies")
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	var result struct {
		Data []FrpsDashboardProxy `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, err
	}
	return result.Data, nil
}

// ============================================================
// frps 进程管理 Handler
// ============================================================

func reloadFrpsHandler(c *gin.Context) {
	if err := GenerateFrpsConfig(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成配置失败: " + err.Error()})
		return
	}
	if err := ReloadFrps(); 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 startFrpsHandler(c *gin.Context) {
	if err := StartFrps(); 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": "frps 启动成功"})
}

func stopFrpsHandler(c *gin.Context) {
	if err := StopFrps(); 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": "frps 已停止"})
}

func getFrpsStatusHandler(c *gin.Context) {
	running, err := GetFrpsStatus()
	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}})
}

// ============================================================
// 导入/导出 TOML
// ============================================================

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

	if err := ReloadFrps(); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code": 0,
			"msg":  "导入成功，但热加载失败: " + err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{"code": 0, "msg": "导入成功"})
}

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
	}

	tmpl, err := template.New("frps").Parse(FrpsTemplateContent)
	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, cfg); 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=frps.toml")
	c.String(http.StatusOK, buf.String())
}

// ============================================================
// 日志读取
// ============================================================

func getFrpsLogHandler(c *gin.Context) {
	lines, err := readTailLog("./frps.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
func readTailLog(filePath string, n int) ([]string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	info, err := file.Stat()
	if err != nil {
		return nil, err
	}
	fileSize := info.Size()
	if fileSize == 0 {
		return []string{}, nil
	}

	const chunkSize = 4096
	var lines []string
	var leftover []byte
	offset := fileSize

	for len(lines) < n && offset > 0 {
		readSize := chunkSize
		if offset < int64(chunkSize) {
			readSize = int(offset)
		}
		offset -= int64(readSize)

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

		data := append(buf, leftover...)
		leftover = nil

		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
			}
		}

		if len(lines) < n && start > 0 {
			leftover = data[:start]
		}
	}

	if len(lines) < n && len(leftover) > 0 {
		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
}