package handler

import (
	"net/http"
	"time"

	"lmvpn/internal/db"
	"lmvpn/internal/middleware"
	"lmvpn/internal/model"

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

type loginRequest struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

type loginResponse struct {
	Token string   `json:"token"`
	User  userInfo `json:"user"`
}

type userInfo struct {
	ID       uint   `json:"id"`
	Username string `json:"username"`
	Role     string `json:"role"`
}

func Login(c *gin.Context) {
	var req loginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请输入用户名和密码"})
		return
	}

	var user model.User
	if err := db.DB.Where("username = ?", req.Username).First(&user).Error; err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "用户名或密码错误"})
		return
	}

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

	if user.Status != 1 {
		c.JSON(http.StatusForbidden, gin.H{"error": "账号已被禁用"})
		return
	}

	sessionID := uuid.New().String()
	token, err := middleware.GenerateToken(sessionID, user.ID, user.Username, user.Role)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "生成令牌失败"})
		return
	}

	session := model.Session{
		SessionID: sessionID,
		UserID:    user.ID,
		IP:        c.ClientIP(),
		UserAgent: c.GetHeader("User-Agent"),
		ExpiresAt: time.Now().Add(24 * time.Hour),
	}
	if err := db.DB.Create(&session).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "创建会话失败"})
		return
	}

	c.JSON(http.StatusOK, loginResponse{
		Token: token,
		User: userInfo{
			ID:       user.ID,
			Username: user.Username,
			Role:     user.Role,
		},
	})
}

type changePasswordRequest struct {
	OldPassword string `json:"old_password" binding:"required"`
	NewPassword string `json:"new_password" binding:"required"`
}

func ChangePassword(c *gin.Context) {
	var req changePasswordRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请输入原密码和新密码"})
		return
	}

	if len(req.NewPassword) < 6 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "新密码长度不能少于6位"})
		return
	}

	userID, _ := c.Get("user_id")

	var user model.User
	if err := db.DB.First(&user, userID).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "用户不存在"})
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(req.OldPassword)); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "原密码错误"})
		return
	}

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

	now := time.Now()
	if err := db.DB.Model(&user).Updates(map[string]interface{}{
		"password":             string(hash),
		"token_invalid_before": now,
	}).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "密码修改失败"})
		return
	}

	sessionID, _ := c.Get("session_id")
	db.DB.Model(&model.Session{}).Where("user_id = ? AND session_id != ?", userID, sessionID).Update("invalid", true)

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

func Me(c *gin.Context) {
	userID, _ := c.Get("user_id")
	username, _ := c.Get("username")
	role, _ := c.Get("role")

	c.JSON(http.StatusOK, userInfo{
		ID:       userID.(uint),
		Username: username.(string),
		Role:     role.(string),
	})
}