// Package handlers
package handlers

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

	"github.com/photoplaces/backend/internal/middleware"
	"github.com/photoplaces/backend/internal/services"
	"github.com/photoplaces/backend/internal/validator"
)

type AuthHandler struct {
	authSvc  *services.AuthService
	isProd   bool
}

func NewAuthHandler(authSvc *services.AuthService, appEnv string) *AuthHandler {
	return &AuthHandler{
		authSvc: authSvc,
		isProd:  appEnv == "production",
	}
}

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) {
	var req registerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		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")
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	h.setRefreshTokenCookie(w, refreshToken)
	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) {
	var req loginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		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")
			return
		}
		if errors.Is(err, services.ErrUserBanned) {
			writeError(w, http.StatusForbidden, "account is banned")
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	h.setRefreshTokenCookie(w, refreshToken)
	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")
		return
	}

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

	h.setRefreshTokenCookie(w, newRefreshToken)
	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)
	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")
		return
	}

	writeJSON(w, http.StatusOK, map[string]string{"user_id": userID, "role": middleware.GetUserRole(r.Context())})
}

const refreshTokenCookieName = "refresh_token"

func (h *AuthHandler) setRefreshTokenCookie(w http.ResponseWriter, token string) {
	cookie := &http.Cookie{
		Name:     refreshTokenCookieName,
		Value:    token,
		Path:     "/",
		HttpOnly: true,
		Secure:   h.isProd,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   int((30 * 24 * time.Hour).Seconds()),
	}
	http.SetCookie(w, cookie)
}

func getRefreshTokenFromCookie(r *http.Request) string {
	cookie, err := r.Cookie(refreshTokenCookieName)
	if err != nil {
		return ""
	}
	return cookie.Value
}

func (h *AuthHandler) clearRefreshTokenCookie(w http.ResponseWriter) {
	cookie := &http.Cookie{
		Name:     refreshTokenCookieName,
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		Secure:   h.isProd,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   -1,
	}
	http.SetCookie(w, cookie)
}

func writeJSON(w http.ResponseWriter, status int, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}

func writeValidationError(w http.ResponseWriter, err error) {
	var ve validator.ValidationErrors
	if errors.As(err, &ve) {
		details := make(map[string]string)
		for _, fe := range ve {
			details[fe.Field()] = validationMessage(fe.Tag(), fe.Param())
		}
		writeJSON(w, http.StatusUnprocessableEntity, map[string]interface{}{
			"error":   "validation failed",
			"details": details,
		})
		return
	}
	writeError(w, http.StatusBadRequest, err.Error())
}

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
	}
}