// Package handlers
package handlers

import (
	"encoding/json"
	"errors"
	"net/http"

	"gogs.fxtmmsk.ru/foxtime/photoplaces/backend/internal/middleware"
	"gogs.fxtmmsk.ru/foxtime/photoplaces/backend/internal/services"
	"gogs.fxtmmsk.ru/foxtime/photoplaces/backend/internal/validator"
)

type AuthHandler struct {
	authSvc AuthService
}

func NewAuthHandler(authSvc AuthService) *AuthHandler {
	return &AuthHandler{authSvc: authSvc}
}

type registerRequest struct {
	Email    string `json:"email" validate:"required,email,max=255"`
	Password string `json:"password" validate:"required,min=8,max=72"`
	Role     string `json:"role" validate:"omitempty,user_role"`
	Name     string `json:"name" validate:"omitempty,max=255"`
}

func (h *AuthHandler) Register(w http.ResponseWriter, r *http.Request) {
	r.Body = http.MaxBytesReader(w, r.Body, maxRequestBodySize)
	var req registerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body", err)
		return
	}

	if err := validator.Validate(req); err != nil {
		writeValidationError(w, err)
		return
	}

	if req.Role == "" {
		req.Role = "customer"
	}

	result, refreshToken, err := h.authSvc.Register(r.Context(), services.RegisterInput{
		Email:    req.Email,
		Password: req.Password,
		Role:     req.Role,
		Name:     req.Name,
	})
	if err != nil {
		if errors.Is(err, services.ErrEmailExists) {
			writeError(w, http.StatusConflict, "email already exists", err)
			return
		}
		writeError(w, http.StatusInternalServerError, "registration failed", err)
		return
	}

	setRefreshTokenCookie(w, refreshToken, r)
	writeJSON(w, http.StatusCreated, result)
}

type loginRequest struct {
	Email    string `json:"email" validate:"required,email,max=255"`
	Password string `json:"password" validate:"required,max=72"`
}

func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
	r.Body = http.MaxBytesReader(w, r.Body, maxRequestBodySize)
	var req loginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body", err)
		return
	}

	if err := validator.Validate(req); err != nil {
		writeValidationError(w, err)
		return
	}

	result, refreshToken, err := h.authSvc.Login(r.Context(), services.LoginInput{
		Email:    req.Email,
		Password: req.Password,
	})
	if err != nil {
		if errors.Is(err, services.ErrInvalidCreds) {
			writeError(w, http.StatusUnauthorized, "invalid email or password", err)
			return
		}
		if errors.Is(err, services.ErrUserBanned) {
			writeError(w, http.StatusForbidden, "account is banned", err)
			return
		}
		writeError(w, http.StatusInternalServerError, "login failed", err)
		return
	}

	setRefreshTokenCookie(w, refreshToken, r)
	writeJSON(w, http.StatusOK, result)
}

func (h *AuthHandler) Refresh(w http.ResponseWriter, r *http.Request) {
	refreshToken := getRefreshTokenFromCookie(r)
	if refreshToken == "" {
		writeError(w, http.StatusBadRequest, "refresh token required", nil)
		return
	}

	result, newRefreshToken, err := h.authSvc.RefreshSession(r.Context(), refreshToken)
	if err != nil {
		if errors.Is(err, services.ErrTokenReused) {
			h.clearRefreshTokenCookie(w, r)
			writeError(w, http.StatusUnauthorized, "token reused, session revoked", err)
			return
		}
		h.clearRefreshTokenCookie(w, r)
		writeError(w, http.StatusUnauthorized, "invalid or expired refresh token", err)
		return
	}

	setRefreshTokenCookie(w, newRefreshToken, r)
	writeJSON(w, http.StatusOK, result)
}

func (h *AuthHandler) Logout(w http.ResponseWriter, r *http.Request) {
	refreshToken := getRefreshTokenFromCookie(r)
	if refreshToken != "" {
		_ = h.authSvc.RevokeSession(r.Context(), refreshToken)
	}
	h.clearRefreshTokenCookie(w, r)
	w.WriteHeader(http.StatusNoContent)
}

func (h *AuthHandler) Me(w http.ResponseWriter, r *http.Request) {
	userID := middleware.GetUserID(r.Context())
	if userID == "" {
		writeError(w, http.StatusUnauthorized, "not authenticated", nil)
		return
	}

	user, err := h.authSvc.GetUser(r.Context(), userID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to get user", err)
		return
	}
	if user == nil {
		writeError(w, http.StatusUnauthorized, "user not found", nil)
		return
	}

	writeJSON(w, http.StatusOK, user)
}

func (h *AuthHandler) clearRefreshTokenCookie(w http.ResponseWriter, r *http.Request) {
	secure := isSecure(r)
	sameSite := http.SameSiteLaxMode
	if secure {
		sameSite = http.SameSiteStrictMode
	}
	http.SetCookie(w, &http.Cookie{
		Name:     refreshTokenCookieName,
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		Secure:   secure,
		SameSite: sameSite,
		MaxAge:   -1,
	})
}

func validationMessage(tag, param string) string {
	switch tag {
	case "required":
		return "field is required"
	case "email":
		return "invalid email format"
	case "min":
		return "value too short (min " + param + ")"
	case "max":
		return "value too long (max " + param + ")"
	case "user_role":
		return "invalid role (customer, landlord, executor, moderator, superadmin)"
	case "latitude":
		return "latitude must be between -90 and 90"
	case "longitude":
		return "longitude must be between -180 and 180"
	case "place_type":
		return "type must be 'place' or 'studio'"
	case "currency":
		return "currency must be 3-letter ISO code"
	case "uuid":
		return "invalid UUID format"
	case "slug":
		return "invalid slug format (lowercase, numbers, hyphens only)"
	default:
		return "validation failed: " + tag
	}
}