feat: implement song endpoint

lib/src/endpoints/song.dart

@@ -0,0 +1,32 @@
+import 'package:dio/dio.dart';
+import 'package:jiosaavn/src/client.dart';
+import 'package:jiosaavn/src/collection/endpoints.dart';
+import 'package:jiosaavn/src/models/song.dart';
+
+class SongEndpoint extends BaseClient {
+  SongEndpoint([super.options]);
+
+  Future<List<SongResponse>> detailsById(List<String> ids) async {
+    // api v4 does not contain media_preview_url
+    final response = await request(call: endpoints.songs.id, queryParameters: {
+      "pids": ids.join(','),
+    });
+
+    if (response["songs"] == null || response["songs"]?.isNotEmpty == false)
+      throw DioException(
+        requestOptions: RequestOptions(
+          baseUrl: options?.baseUrl,
+          queryParameters: options?.queryParameters,
+        ),
+        error: "No songs found",
+        type: DioExceptionType.badResponse,
+      );
+
+    return (response["songs"] as List)
+        .map(
+          (song) => SongResponse.fromSongRequest(SongRequest.fromJson(song)),
+        )
+        .toList()
+        .cast<SongResponse>();
+  }
+}

lib/src/models/song.dart

@@ -53,7 +53,7 @@ class SongRequest {
   String language;
   String origin;
 
-  @JsonKey(name: "play_count")
+  @JsonKey(name: "play_count", fromJson: SongRequest._toString)
   String? playCount;
 
   @JsonKey(name: "copyright_text")

test/endpoints/song.dart

@@ -0,0 +1,16 @@
+import 'package:jiosaavn/src/endpoints/song.dart';
+import 'package:jiosaavn/src/models/song.dart';
+import 'package:test/test.dart';
+
+void main(List<String> args) {
+  final song = SongEndpoint();
+
+  group("Song Endpoint => ", () {
+    test("Get song Details by Ids", () async {
+      final res = await song.detailsById(["5WXAlMNt", "csaEsVWV"]);
+
+      expect(res, isA<List<SongResponse>>());
+      expect(res, hasLength(2));
+    });
+  });
+}