load trending images from tmdb at startup

- need TMDB_API_KEY as environment variable
- mount /cache for data persistence

Signed-off-by: Peter Siegmund <developer@mars3142.org>

server/cinema/lib/common/dio_module.dart

@@ -0,0 +1,39 @@
+import 'dart:io';
+
+import 'package:cinema/feature/version/version.dart';
+import 'package:dio/dio.dart';
+import 'package:injectable/injectable.dart';
+
+const dioAPI = 'api';
+const dioIMAGES = 'images';
+
+@module
+abstract class DioModule {
+  @Named(dioAPI)
+  @lazySingleton
+  Dio get apiDio =>
+      Dio( // Der Getter selbst wird annotiert und gibt die Instanz zurück
+        BaseOptions(
+          baseUrl: 'https://api.themoviedb.org/3',
+          connectTimeout: const Duration(seconds: 10),
+          receiveTimeout: const Duration(seconds: 10),
+          headers: {
+            'Authorization': 'Bearer ${Platform.environment['TMDB_API_KEY']}',
+            'Content-Type': 'application/json',
+            'Accept': 'application/json',
+            'User-Agent': 'Cinema Service (v${Version().appVersion})'
+          },
+        ),
+      );
+
+  @Named(dioIMAGES)
+  @lazySingleton
+  Dio get imagesDio =>
+      Dio( // Der Getter selbst wird annotiert und gibt die Instanz zurück
+        BaseOptions(
+          baseUrl: 'https://image.tmdb.org/t/p/original',
+          connectTimeout: const Duration(seconds: 10),
+          receiveTimeout: const Duration(seconds: 10),
+        ),
+      );
+}

server/cinema/lib/common/domain/custom_date_time_serializer.dart

@@ -0,0 +1,32 @@
+import 'package:built_value/serializer.dart';
+
+/// A custom serializer for [DateTime] objects that are represented as
+/// a simple date string "yyyy-MM-dd" in JSON.
+class CustomDateTimeSerializer implements PrimitiveSerializer<DateTime> {
+  @override
+  final Iterable<Type> types = const [DateTime];
+
+  @override
+  final String wireName = 'DateTime';
+
+  @override
+  Object serialize(Serializers serializers, DateTime dateTime,
+      {FullType specifiedType = FullType.unspecified}) {
+    // On serialization, convert DateTime to a "yyyy-MM-dd" string.
+    return dateTime.toIso8601String().substring(0, 10);
+  }
+
+  @override
+  DateTime deserialize(Serializers serializers, Object serialized,
+      {FullType specifiedType = FullType.unspecified}) {
+    // On deserialization, parse the string to a DateTime object.
+    // This handles formats like "2025-09-23".
+    final parts = (serialized as String).split('-');
+    final dateUtc = DateTime.utc(
+      int.parse(parts[0]),
+      int.parse(parts[1]),
+      int.parse(parts[2]),
+    );
+    return dateUtc;
+  }
+}

server/cinema/lib/common/domain/serializers.dart

@@ -0,0 +1,20 @@
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/serializer.dart';
+import 'package:built_value/standard_json_plugin.dart';
+import 'package:cinema/feature/poster/domain/movie.dart';
+import 'package:cinema/feature/poster/domain/tmdb_trending_response.dart';
+
+import 'custom_date_time_serializer.dart';
+
+part 'serializers.g.dart';
+
+@SerializersFor([TmdbTrendingResponse, TmdbMovieResult])
+final Serializers serializers =
+    (_$serializers.toBuilder()
+          ..add(CustomDateTimeSerializer())
+          ..addPlugin(StandardJsonPlugin())
+          ..addBuilderFactory(
+            const FullType(BuiltList, [FullType(TmdbMovieResult), FullType(Movie)]),
+            () => ListBuilder<TmdbMovieResult>(),
+          ))
+        .build();

server/cinema/lib/feature/poster/data/repositories/image_loader.dart

@@ -0,0 +1,7 @@
+import 'package:cinema/feature/poster/domain/movie.dart';
+
+abstract class ImageLoader {
+  Future<List<Movie>> getPosterURIs({String? language = 'de'});
+
+  Future<bool> downloadImages(Movie movie);
+}

server/cinema/lib/feature/poster/data/repositories/tmdb_image_loader.dart

@@ -0,0 +1,57 @@
+import 'dart:io';
+
+import 'package:cinema/common/dio_module.dart';
+import 'package:cinema/common/domain/serializers.dart';
+import 'package:cinema/feature/poster/data/repositories/image_loader.dart';
+import 'package:cinema/feature/poster/domain/movie.dart';
+import 'package:cinema/feature/poster/domain/tmdb_trending_response.dart';
+import 'package:dio/dio.dart';
+import 'package:injectable/injectable.dart';
+
+@Injectable(as: ImageLoader)
+class TmDBImageLoader implements ImageLoader {
+  final Dio api;
+  final Dio images;
+  final String imageBaseUrl = 'https://image.tmdb.org/t/p/w500';
+
+  TmDBImageLoader(@Named(dioAPI) this.api, @Named(dioIMAGES) this.images);
+
+  @override
+  Future<List<Movie>> getPosterURIs({String? language = 'de'}) async {
+    final response = await api.get('/trending/movie/week?language=$language');
+    if (response.data != null) {
+      final data = serializers.deserializeWith(TmdbTrendingResponse.serializer, response.data);
+      return data?.results
+              .map(
+                (movie) => Movie(
+                  (b) => b
+                    ..id = movie.id
+                    ..poster = movie.posterPath
+                    ..backdrop = movie.backdropPath,
+                ),
+              )
+              .toList() ??
+          [];
+    }
+    return [];
+  }
+
+  @override
+  Future<bool> downloadImages(Movie movie) async {
+    await downloadImage(movie.poster, "cache/movie/${movie.id}/poster.png");
+    await downloadImage(movie.backdrop, "cache/movie/${movie.id}/backdrop.png");
+    return true;
+  }
+
+  Future<bool> downloadImage(String url, String filename) async {
+    final file = File(filename);
+    if (await file.exists()) {
+      return false;
+    }
+
+    await file.parent.create(recursive: true);
+    final response = await images.get(url, options: Options(responseType: ResponseType.bytes));
+    await file.writeAsBytes(response.data);
+    return true;
+  }
+}

server/cinema/lib/feature/poster/data/services/poster.service.dart

@@ -1,6 +1,6 @@
 import 'dart:convert';
 
-import 'package:cinema/feature/poster/models/poster_request.schema.dart';
+import 'package:cinema/feature/poster/domain/poster_request.schema.dart';
 import 'package:injectable/injectable.dart';
 import 'package:shelf/shelf.dart';
 import 'package:shelf_router/shelf_router.dart';

server/cinema/lib/feature/poster/domain/movie.dart

@@ -0,0 +1,18 @@
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'movie.g.dart';
+
+abstract class Movie implements Built<Movie, MovieBuilder> {
+  static Serializer<Movie> get serializer => _$movieSerializer;
+
+  int get id;
+
+  String get poster;
+
+  String get backdrop;
+
+  Movie._();
+
+  factory Movie([void Function(MovieBuilder) updates]) = _$Movie;
+}

server/cinema/lib/feature/poster/domain/poster_request.schema.dart

@@ -1,4 +1,4 @@
-import 'package:cinema/feature/poster/models/poster.enums.dart';
+import 'package:cinema/feature/poster/domain/poster.enums.dart';
 import 'package:zard/zard.dart';
 
 final _orientations = PosterOrientation.values.map((e) => e.name);

server/cinema/lib/feature/poster/domain/tmdb_trending_response.dart

@@ -0,0 +1,69 @@
+import 'dart:convert';
+
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'tmdb_trending_response.g.dart';
+
+abstract class TmdbTrendingResponse implements Built<TmdbTrendingResponse, TmdbTrendingResponseBuilder> {
+  static Serializer<TmdbTrendingResponse> get serializer => _$tmdbTrendingResponseSerializer;
+
+  int get page;
+
+  BuiltList<TmdbMovieResult> get results;
+
+  @BuiltValueField(wireName: 'total_pages')
+  int get totalPages;
+
+  @BuiltValueField(wireName: 'total_results')
+  int get totalResults;
+
+  TmdbTrendingResponse._();
+
+  factory TmdbTrendingResponse([void Function(TmdbTrendingResponseBuilder) updates]) = _$TmdbTrendingResponse;
+}
+
+abstract class TmdbMovieResult implements Built<TmdbMovieResult, TmdbMovieResultBuilder> {
+  static Serializer<TmdbMovieResult> get serializer => _$tmdbMovieResultSerializer;
+
+  bool get adult;
+
+  @BuiltValueField(wireName: 'backdrop_path')
+  String get backdropPath;
+
+  int get id;
+
+  String get title;
+
+  @BuiltValueField(wireName: 'original_title')
+  String get originalTitle;
+
+  String get overview;
+
+  @BuiltValueField(wireName: 'poster_path')
+  String get posterPath;
+
+  @BuiltValueField(wireName: 'media_type')
+  String get mediaType;
+
+  @BuiltValueField(wireName: 'genre_ids')
+  BuiltList<int> get genreIds;
+
+  double get popularity;
+
+  @BuiltValueField(wireName: 'release_date')
+  DateTime get releaseDate;
+
+  bool get video;
+
+  @BuiltValueField(wireName: 'vote_average')
+  double get voteAverage;
+
+  @BuiltValueField(wireName: 'vote_count')
+  int get voteCount;
+
+  TmdbMovieResult._();
+
+  factory TmdbMovieResult([void Function(TmdbMovieResultBuilder) updates]) = _$TmdbMovieResult;
+}