package auth

import (
	"errors"
	"log"
	"net/http"

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

type Handler struct {
	service *Service
}

func NewHandler(service *Service) *Handler {
	return &Handler{service: service}
}

// @Summary      Register epta
// @Description  Create user account with username, email, password
// @Tags         auth
// @Accept       json
// @Produce      json
// @Param        request  body  RegisterRequest  true  "Registration details"
// @Success      201  {object}  AuthResponse
// @Failure      400  {object}  ErrorResponse
// @Failure      409  {object}  ErrorResponse
// @Router       /api/auth/register [post]
func (h *Handler) Register(c *gin.Context) {
	var req RegisterRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	resp, err := h.service.Register(c.Request.Context(), req)
	if err != nil {
		if errors.Is(err, ErrEmailExists) {
			c.JSON(http.StatusConflict, ErrorResponse{Error: err.Error()})
			return
		}
		if errors.Is(err, ErrWeakPassword) {
			c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("register error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusCreated, resp)
}

// @Summary      Login
// @Description  Authenticate user with email and password, returns JWT token
// @Tags         auth
// @Accept       json
// @Produce      json
// @Param        request  body  LoginRequest  true  "Login credentials"
// @Success      200  {object}  AuthResponse
// @Failure      400  {object}  ErrorResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/login [post]
func (h *Handler) Login(c *gin.Context) {
	var req LoginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	resp, err := h.service.Login(c.Request.Context(), req)
	if err != nil {
		if errors.Is(err, ErrInvalidCreds) {
			c.JSON(http.StatusUnauthorized, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("login error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, resp)
}

// @Summary      Refresh epta token
// @Description  Get a new access token using a refresh token
// @Tags         auth
// @Accept       json
// @Produce      json
// @Param        request  body  RefreshRequest  true  "Refresh token"
// @Success      200  {object}  AuthResponse
// @Failure      400  {object}  ErrorResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/refresh [post]
func (h *Handler) Refresh(c *gin.Context) {
	var req RefreshRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	resp, err := h.service.Refresh(c.Request.Context(), req.RefreshToken)
	if err != nil {
		if errors.Is(err, ErrInvalidRefresh) || errors.Is(err, ErrRefreshExpired) {
			c.JSON(http.StatusUnauthorized, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("refresh error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, resp)
}

// @Summary      Logout epta
// @Description  Invalidate a refresh token (logout)
// @Tags         auth
// @Accept       json
// @Produce      json
// @Param        request  body  LogoutRequest  true  "Refresh token to invalidate"
// @Success      200  {object}  map[string]string
// @Failure      400  {object}  ErrorResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/logout [post]
func (h *Handler) Logout(c *gin.Context) {
	var req LogoutRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	if err := h.service.Logout(c.Request.Context(), req.RefreshToken); err != nil {
		if errors.Is(err, ErrLogoutInvalid) {
			c.JSON(http.StatusUnauthorized, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("logout error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "logged out successfully"})
}

// @Summary      Get epta current user
// @Description  Get authenticated user's profile
// @Tags         auth
// @Accept       json
// @Produce      json
// @Security     Bearer
// @Success      200  {object}  UserResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/me [get]
func (h *Handler) Me(c *gin.Context) {
	rawUserID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, ErrorResponse{Error: "unauthorized"})
		return
	}

	userID, ok := rawUserID.(string)
	if !ok {
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "invalid user ID in context"})
		return
	}

	user, err := h.service.GetUserByID(c.Request.Context(), userID)
	if err != nil {
		if errors.Is(err, ErrUserNotFound) || errors.Is(err, ErrInvalidUserID) {
			c.JSON(http.StatusNotFound, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("me error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, UserResponse{User: *user})
}

// @Summary      Change epta password
// @Description  Change current user's password
// @Tags         auth
// @Accept       json
// @Produce      json
// @Security     Bearer
// @Param        request  body  PasswordChangeRequest  true  "Password change details"
// @Success      200  {object}  map[string]string
// @Failure      400  {object}  ErrorResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/password [put]
func (h *Handler) ChangePassword(c *gin.Context) {
	rawUserID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, ErrorResponse{Error: "unauthorized"})
		return
	}

	userID, ok := rawUserID.(string)
	if !ok {
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "invalid user ID in context"})
		return
	}

	var req PasswordChangeRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	if err := h.service.ChangePassword(c.Request.Context(), userID, req); err != nil {
		if errors.Is(err, ErrWrongPassword) || errors.Is(err, ErrSamePassword) || errors.Is(err, ErrWeakPassword) {
			c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
			return
		}
		if errors.Is(err, ErrUserNotFound) || errors.Is(err, ErrInvalidUserID) {
			c.JSON(http.StatusNotFound, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("change password error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "password changed successfully"})
}

// @Summary      Update epta profile
// @Description  Update current user's username
// @Tags         auth
// @Accept       json
// @Produce      json
// @Security     Bearer
// @Param        request  body  UpdateProfileRequest  true  "Profile update"
// @Success      200  {object}  UserResponse
// @Failure      400  {object}  ErrorResponse
// @Failure      401  {object}  ErrorResponse
// @Router       /api/auth/me [put]
func (h *Handler) UpdateProfile(c *gin.Context) {
	rawUserID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, ErrorResponse{Error: "unauthorized"})
		return
	}

	userID, ok := rawUserID.(string)
	if !ok {
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "invalid user ID in context"})
		return
	}

	var req UpdateProfileRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{Error: err.Error()})
		return
	}

	user, err := h.service.UpdateProfile(c.Request.Context(), userID, req)
	if err != nil {
		if errors.Is(err, ErrUserNotFound) || errors.Is(err, ErrInvalidUserID) {
			c.JSON(http.StatusNotFound, ErrorResponse{Error: err.Error()})
			return
		}
		log.Printf("update profile error: %v", err)
		c.JSON(http.StatusInternalServerError, ErrorResponse{Error: "internal server error"})
		return
	}

	c.JSON(http.StatusOK, UserResponse{User: *user})
}