feat: add image upload

import 'dart:io';

import 'package:cloud_firestore/cloud_firestore.dart';

import 'package:firebase_storage/firebase_storage.dart';

import 'package:path/path.dart' as p;

import 'package:stamped/data/entities/country_entity.dart';

import 'package:stamped/data/enums/image_type.dart';

class MediaService {

  final _postcardImagesRef =

      FirebaseStorage.instance.ref().child('postcardImages');

  final _stampsRef = FirebaseStorage.instance.ref().child('stamps');

  final _countryCollection =

      FirebaseFirestore.instance.collection('countries').withConverter(

    fromFirestore: (snapshot, options) {

    return countrySnapshot.data()!.flag;

  }

  Future<void> uploadImage() async {

    //TODO

  Future<Reference?> uploadImage(

    File file, {

    required ImageType imageType,

  }) async {

    final storageRef =

        imageType == ImageType.postcard ? _postcardImagesRef : _stampsRef;

    final fileName = _genUniqueFileName(file);

    final uploadTask = await storageRef.child(fileName).putFile(file);

    if (uploadTask.state != TaskState.success) {

      return null;

    }

    return storageRef.child(fileName);

  }

  String _genUniqueFileName(File file) {

    final time = DateTime.now().millisecondsSinceEpoch.toString();

    return '$time${p.basename(file.path)}';

  }

  Future<void> deleteImage() async {