// handlers/auth_handler.go
package handlers

import (
	"errors"
	"net/http"
	"strings"

	"go-todo-api/constants"
	"go-todo-api/dto"
	"go-todo-api/services"

	"github.com/gin-gonic/gin"
)

// AuthHandler 依赖于 AuthService 接口
type AuthHandler struct {
	Service services.AuthService
}

// NewAuthHandler 创建 AuthHandler 的新实例
func NewAuthHandler(service services.AuthService) *AuthHandler {
	return &AuthHandler{Service: service}
}

// RegisterHandler 处理 POST /register 请求
func (h *AuthHandler) RegisterHandler(c *gin.Context) {
	var input dto.RegisterInput
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, constants.StandardResponse{
			Code:    constants.CodeValidationError,
			Message: "Invalid input format or missing fields",
		})
		return
	}

	newUser, err := h.Service.Register(&input)

	if err != nil {
		if strings.Contains(err.Error(), "username already taken") { // 检查 Service 返回的特定错误
			c.JSON(http.StatusConflict, constants.StandardResponse{
				Code:    constants.CodeConflictError,
				Message: "Username already taken",
			})
			return
		}
		c.JSON(http.StatusInternalServerError, constants.StandardResponse{
			Code:    constants.CodeInternalError,
			Message: "Failed to register user",
		})
		return
	}

	// 注册成功，返回脱敏信息
	c.JSON(http.StatusCreated, constants.StandardResponse{
		Code:    constants.CodeSuccess,
		Message: "User created successfully",
		Data:    newUser,
	})
}

// LoginHandler 处理 POST /login 请求
func (h *AuthHandler) LoginHandler(c *gin.Context) {
	var input dto.LoginInput
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, constants.StandardResponse{
			Code:    constants.CodeValidationError,
			Message: "Invalid input format or missing fields",
		})
		return
	}

	token, err := h.Service.Login(&input)

	if err != nil {
		// 统一处理登录失败，防止泄露细节
		if errors.Is(err, errors.New("invalid username or password")) {
			c.JSON(http.StatusUnauthorized, constants.StandardResponse{
				Code:    constants.CodeInvalidAuth,
				Message: "Invalid username or password",
			})
			return
		}
		c.JSON(http.StatusInternalServerError, constants.StandardResponse{
			Code:    constants.CodeInternalError,
			Message: "Failed to login",
		})
		return
	}

	// 登录成功，返回令牌
	c.JSON(http.StatusOK, constants.StandardResponse{
		Code:    constants.CodeSuccess,
		Message: "Login successful!",
		Data:    token,
	})
}