package api

import (
	"bytes"
	"fmt"
	"html/template"
	"net"
	"net/http"
	"strconv"
	"time"

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

	"frpc-console/internal/auth"
	"frpc-console/internal/db"
	"frpc-console/internal/frp"
)

// ================================================================
// 认证 Handler
// ================================================================

func CheckUsersHandler(c *gin.Context) {
	count, err := db.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 := db.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 !auth.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 := db.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 := auth.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 := db.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 := auth.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 := auth.GetUsernameFromContext(c)
	if username == "" {
		c.JSON(http.StatusUnauthorized, gin.H{"code": 1, "msg": "未登录"})
		return
	}

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

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

	if err := frp.Reload(); 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"})
}

// ================================================================
// 隧道 Handler
// ================================================================

func GetProxiesHandler(c *gin.Context) {
	proxies, err := db.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 := db.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 db.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 := db.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 db.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 := db.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 := db.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"})
}

// ================================================================
// frpc 进程管理 Handler
// ================================================================

func ReloadFrpcHandler(c *gin.Context) {
	if err := frp.GenerateConfig(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "生成配置失败: " + err.Error()})
		return
	}
	if err := frp.Reload(); 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 := frp.Start(); 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 := frp.Stop(); 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) {
	status, err := frp.GetStatus()
	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": status})
}

// ================================================================
// Ping Handler
// ================================================================

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
	}

	cfg, err := db.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})
}

// ================================================================
// 日志 Handler
// ================================================================

func GetFrpcLogHandler(c *gin.Context) {
	lines, err := frp.ReadTailLog("./data/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),
		},
	})
}

// ================================================================
// 辅助函数
// ================================================================

func generateAndReload() error {
	if err := frp.GenerateConfig(); err != nil {
		return err
	}
	return frp.Reload()
}

// readTailLog 读取文件末尾 n 行 (临时放在这里，后续移到独立包)
func readTailLog(filePath string, n int) ([]string, error) {
	// 这个函数在 frp 模块中也有，但为了避免循环依赖，在这里实现一份简单的
	// 或者直接调用 frp.ReadTailLog 如果导出的话
	// 目前保持和原来一致，后续可以统一到 pkg/utils
	// 为了编译通过，先简单返回空
	return []string{}, nil
}

// ================================================================
// 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 := frp.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 := db.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.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 := db.CreateProxy(&p); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "导入隧道失败: " + err.Error()})
			return
		}
	}

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

	if err := frp.Reload(); 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 := db.GetGlobalConfig()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 2, "msg": "读取配置失败: " + err.Error()})
		return
	}

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

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

	data := struct {
		*db.GlobalConfig
		Proxies          []db.Proxy
		WireProtocolLine string
	}{
		GlobalConfig: cfg,
		Proxies:      activeProxies,
	}

	if cfg.WireProtocolV2 {
		data.WireProtocolLine = `wireProtocol = "v2"`
	} else {
		data.WireProtocolLine = ""
	}

	// 这里需要 frp.FrpcTemplateContent，需要从 frp 包导出
	tmpl, err := template.New("frpc").Parse(frp.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())
}