package handlers

import (
	"errors"
	"net/http"
	"strconv"

	"photography-backend/internal/models"
	"photography-backend/internal/service"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
)

type UserHandler struct {
	userService *service.UserService
	logger      *zap.Logger
}

func NewUserHandler(userService *service.UserService, logger *zap.Logger) *UserHandler {
	return &UserHandler{
		userService: userService,
		logger:      logger,
	}
}

// GetCurrentUser 获取当前用户信息
// @Summary 获取当前用户信息
// @Description 获取当前登录用户的详细信息
// @Tags users
// @Accept json
// @Produce json
// @Success 200 {object} models.UserResponse
// @Failure 401 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /me [get]
func (h *UserHandler) GetCurrentUser(c *gin.Context) {
	userID := c.GetUint("user_id")
	
	user, err := h.userService.GetUserByID(c.Request.Context(), userID)
	if err != nil {
		h.logger.Error("Failed to get current user", zap.Error(err), zap.Uint("user_id", userID))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to get user information",
			Message: err.Error(),
		})
		return
	}
	
	userResponse := &models.UserResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		Role:      user.Role,
		IsActive:  user.IsActive,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
	
	c.JSON(http.StatusOK, userResponse)
}

// UpdateCurrentUser 更新当前用户信息
// @Summary 更新当前用户信息
// @Description 更新当前登录用户的个人信息
// @Tags users
// @Accept json
// @Produce json
// @Param user body models.UpdateCurrentUserRequest true "用户信息"
// @Success 200 {object} models.UserResponse
// @Failure 400 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /me [put]
func (h *UserHandler) UpdateCurrentUser(c *gin.Context) {
	userID := c.GetUint("user_id")
	
	var req models.UpdateCurrentUserRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Failed to bind JSON", zap.Error(err))
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid request body",
			Message: err.Error(),
		})
		return
	}
	
	user, err := h.userService.UpdateCurrentUser(c.Request.Context(), userID, &req)
	if err != nil {
		h.logger.Error("Failed to update current user", zap.Error(err), zap.Uint("user_id", userID))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to update user information",
			Message: err.Error(),
		})
		return
	}
	
	userResponse := &models.UserResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		Role:      user.Role,
		IsActive:  user.IsActive,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
	
	c.JSON(http.StatusOK, userResponse)
}

// GetUsers 获取用户列表 (管理员功能)
// @Summary 获取用户列表
// @Description 获取系统中所有用户列表
// @Tags admin
// @Accept json
// @Produce json
// @Param page query int false "页码"
// @Param limit query int false "每页数量"
// @Param search query string false "搜索关键词"
// @Success 200 {object} service.UserListResponse
// @Failure 403 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /admin/users [get]
func (h *UserHandler) GetUsers(c *gin.Context) {
	var params service.UserListParams
	
	// 解析查询参数
	if err := c.ShouldBindQuery(&params); err != nil {
		h.logger.Error("Failed to bind query params", zap.Error(err))
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid query parameters",
			Message: err.Error(),
		})
		return
	}
	
	result, err := h.userService.GetUsers(c.Request.Context(), params)
	if err != nil {
		h.logger.Error("Failed to get users", zap.Error(err))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to get users",
			Message: err.Error(),
		})
		return
	}
	
	c.JSON(http.StatusOK, result)
}

// GetUser 获取用户详情 (管理员功能)
// @Summary 获取用户详情
// @Description 根据ID获取用户详情
// @Tags admin
// @Accept json
// @Produce json
// @Param id path int true "用户ID"
// @Success 200 {object} models.UserResponse
// @Failure 400 {object} models.ErrorResponse
// @Failure 404 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /admin/users/{id} [get]
func (h *UserHandler) GetUser(c *gin.Context) {
	idStr := c.Param("id")
	id, err := strconv.ParseUint(idStr, 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid user ID",
			Message: "User ID must be a valid number",
		})
		return
	}
	
	user, err := h.userService.GetUserByID(c.Request.Context(), uint(id))
	if err != nil {
		if err.Error() == "user not found" {
			c.JSON(http.StatusNotFound, models.ErrorResponse{
				Error:   "User not found",
				Message: "The requested user does not exist",
			})
			return
		}
		
		h.logger.Error("Failed to get user", zap.Error(err))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to get user",
			Message: err.Error(),
		})
		return
	}
	
	userResponse := &models.UserResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		Role:      user.Role,
		IsActive:  user.IsActive,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
	
	c.JSON(http.StatusOK, userResponse)
}

// CreateUser 创建用户 (管理员功能)
// @Summary 创建用户
// @Description 创建新用户
// @Tags admin
// @Accept json
// @Produce json
// @Param user body models.CreateUserRequest true "用户信息"
// @Success 201 {object} models.UserResponse
// @Failure 400 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /admin/users [post]
func (h *UserHandler) CreateUser(c *gin.Context) {
	var req models.CreateUserRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Failed to bind JSON", zap.Error(err))
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid request body",
			Message: err.Error(),
		})
		return
	}
	
	// 验证请求数据
	if err := h.validateCreateUserRequest(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid request data",
			Message: err.Error(),
		})
		return
	}
	
	user, err := h.userService.CreateUser(c.Request.Context(), &req)
	if err != nil {
		h.logger.Error("Failed to create user", zap.Error(err))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to create user",
			Message: err.Error(),
		})
		return
	}
	
	userResponse := &models.UserResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		Role:      user.Role,
		IsActive:  user.IsActive,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
	
	c.JSON(http.StatusCreated, userResponse)
}

// UpdateUser 更新用户 (管理员功能)
// @Summary 更新用户
// @Description 更新用户信息
// @Tags admin
// @Accept json
// @Produce json
// @Param id path int true "用户ID"
// @Param user body models.UpdateUserRequest true "用户信息"
// @Success 200 {object} models.UserResponse
// @Failure 400 {object} models.ErrorResponse
// @Failure 404 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /admin/users/{id} [put]
func (h *UserHandler) UpdateUser(c *gin.Context) {
	idStr := c.Param("id")
	id, err := strconv.ParseUint(idStr, 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid user ID",
			Message: "User ID must be a valid number",
		})
		return
	}
	
	var req models.UpdateUserRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Error("Failed to bind JSON", zap.Error(err))
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid request body",
			Message: err.Error(),
		})
		return
	}
	
	user, err := h.userService.UpdateUser(c.Request.Context(), uint(id), &req)
	if err != nil {
		if err.Error() == "user not found" {
			c.JSON(http.StatusNotFound, models.ErrorResponse{
				Error:   "User not found",
				Message: "The requested user does not exist",
			})
			return
		}
		
		h.logger.Error("Failed to update user", zap.Error(err))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to update user",
			Message: err.Error(),
		})
		return
	}
	
	userResponse := &models.UserResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		Role:      user.Role,
		IsActive:  user.IsActive,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
	
	c.JSON(http.StatusOK, userResponse)
}

// DeleteUser 删除用户 (管理员功能)
// @Summary 删除用户
// @Description 删除用户
// @Tags admin
// @Accept json
// @Produce json
// @Param id path int true "用户ID"
// @Success 204 "No Content"
// @Failure 400 {object} models.ErrorResponse
// @Failure 404 {object} models.ErrorResponse
// @Failure 500 {object} models.ErrorResponse
// @Router /admin/users/{id} [delete]
func (h *UserHandler) DeleteUser(c *gin.Context) {
	idStr := c.Param("id")
	id, err := strconv.ParseUint(idStr, 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Invalid user ID",
			Message: "User ID must be a valid number",
		})
		return
	}
	
	// 防止删除自己
	currentUserID := c.GetUint("user_id")
	if uint(id) == currentUserID {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			Error:   "Cannot delete yourself",
			Message: "You cannot delete your own account",
		})
		return
	}
	
	err = h.userService.DeleteUser(c.Request.Context(), uint(id))
	if err != nil {
		if err.Error() == "user not found" {
			c.JSON(http.StatusNotFound, models.ErrorResponse{
				Error:   "User not found",
				Message: "The requested user does not exist",
			})
			return
		}
		
		h.logger.Error("Failed to delete user", zap.Error(err))
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			Error:   "Failed to delete user",
			Message: err.Error(),
		})
		return
	}
	
	c.Status(http.StatusNoContent)
}

// validateCreateUserRequest 验证创建用户请求
func (h *UserHandler) validateCreateUserRequest(req *models.CreateUserRequest) error {
	if req.Username == "" {
		return errors.New("username is required")
	}
	
	if req.Email == "" {
		return errors.New("email is required")
	}
	
	if req.Password == "" {
		return errors.New("password is required")
	}
	
	if req.Role == "" {
		req.Role = "user"
	}
	
	// 验证角色
	validRoles := []string{"user", "editor", "admin"}
	isValidRole := false
	for _, role := range validRoles {
		if req.Role == role {
			isValidRole = true
			break
		}
	}
	
	if !isValidRole {
		return errors.New("invalid role value")
	}
	
	return nil
}