package middleware

import (
	"context"
	"errors"
	"fmt"
	"net/http"

	"github.com/google/uuid"
)

func CorsMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Add("Access-Control-Allow-Origin", "*")
		w.Header().Add("Access-Control-Allow-Headers", "*")

		// Access-Control-Allow-Methods is often needed for preflight OPTIONS requests
		w.Header().Add("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")

		// The client makes an OPTIONS preflight request before a complex request.
		// We must handle this and respond with the appropriate headers.
		if r.Method == "OPTIONS" {
			w.WriteHeader(http.StatusOK)
			return
		}

		next.ServeHTTP(w, r)
	})
}

const USER_ID = "UserID"

func GetUserID(ctx context.Context) (uuid.UUID, error) {
	userId := ctx.Value(USER_ID)

	if userId == nil {
		return uuid.Nil, errors.New("context does not contain a user id")
	}

	userIdUuid, ok := userId.(uuid.UUID)
	if !ok {
		return uuid.Nil, fmt.Errorf("context user id is not of type uuid, got: %t", userId)
	}

	return userIdUuid, nil
}

func ProtectedRoute(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		token := r.Header.Get("Authorization")
		if len(token) < len("Bearer ") {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		userId, err := GetUserIdFromAccess(token[len("Bearer "):])
		if err != nil {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		contextWithUserId := context.WithValue(r.Context(), USER_ID, userId)

		newR := r.WithContext(contextWithUserId)
		next.ServeHTTP(w, newR)
	})
}

func GetUserIdFromUrl(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		token := r.URL.Query().Get("token")

		if len(token) == 0 {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		userId, err := GetUserIdFromAccess(token)
		if err != nil {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		contextWithUserId := context.WithValue(r.Context(), USER_ID, userId)

		newR := r.WithContext(contextWithUserId)
		next.ServeHTTP(w, newR)
	})
}