package handlers

import (
	"strings"

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

	"soda-api/backend/internal/models"
	"soda-api/backend/internal/utils"
)

type AuthHandler struct {
	db         *gorm.DB
	jwtManager *utils.JWTManager
}

func NewAuthHandler(db *gorm.DB, jwt *utils.JWTManager) *AuthHandler {
	return &AuthHandler{db: db, jwtManager: jwt}
}

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

type RegisterRequest struct {
	Username string `json:"username" binding:"required,min=3"`
	Password string `json:"password" binding:"required,min=6"`
	Email    string `json:"email"`
}

func (h *AuthHandler) Login(c *gin.Context) {
	var req LoginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		utils.JSONError(c, 400, "请输入用户名与密码")
		return
	}
	var user models.User
	if err := h.db.Where("LOWER(username)=?", strings.ToLower(req.Username)).First(&user).Error; err != nil {
		utils.JSONError(c, 401, "账号或密码错误")
		return
	}
	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.Password)); err != nil {
		utils.JSONError(c, 401, "账号或密码错误")
		return
	}
	token, err := h.jwtManager.Generate(user.ID, user.Username, user.Role)
	if err != nil {
		utils.JSONError(c, 500, "生成令牌失败")
		return
	}
	utils.JSONSuccess(c, gin.H{
		"token": token,
		"user": gin.H{
			"id":       user.ID,
			"username": user.Username,
			"role":     user.Role,
		},
	})
}

func (h *AuthHandler) Register(c *gin.Context) {
	var req RegisterRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		utils.JSONError(c, 400, "请填写完整注册信息")
		return
	}
	passwordHash, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		utils.JSONError(c, 500, "密码加密失败")
		return
	}
	user := models.User{Username: req.Username, PasswordHash: string(passwordHash), Role: "merchant"}
	if err := h.db.Create(&user).Error; err != nil {
		utils.JSONError(c, 400, "用户名已存在")
		return
	}
	utils.JSONSuccess(c, gin.H{"message": "注册成功，请使用新账号登录"})
}