feature: Added LibMDK video player backend (#162)

Co-authored-by: PartyDonut <PartyDonut@users.noreply.github.com>

lib/wrappers/players/base_player.dart

@@ -0,0 +1,50 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'package:fladder/models/items/media_streams_model.dart';
+import 'package:fladder/models/playback/playback_model.dart';
+import 'package:fladder/wrappers/players/player_states.dart';
+
+const libassFallbackFont = "assets/mp-font.ttf";
+
+abstract class BasePlayer {
+  Stream<PlayerState> get stateStream;
+  PlayerState lastState = PlayerState();
+
+  Future<void> init(Ref ref);
+  Widget? videoWidget(
+    Key key,
+    BoxFit fit,
+  );
+  Widget? subtitles(
+    bool showOverlay,
+  );
+  Future<void> dispose();
+  Future<void> open(String url, bool play);
+  Future<void> seek(Duration position);
+  Future<void> play();
+  Future<void> setVolume(double volume);
+  Future<void> setSpeed(double speed);
+  Future<void> pause();
+  Future<void> stop();
+  Future<void> playOrPause();
+  Future<void> loop(bool loop);
+  Future<int> setSubtitleTrack(SubStreamModel? model, PlaybackModel playbackModel);
+  Future<int> setAudioTrack(AudioStreamModel? model, PlaybackModel playbackModel);
+
+  Uri? isValidUrl(String input) {
+    try {
+      final uri = Uri.tryParse(input);
+      if (uri != null && uri.isAbsolute && (uri.scheme == 'http' || uri.scheme == 'https')) {
+        return uri;
+      } else {
+        return null;
+      }
+    } catch (e) {
+      return null;
+    }
+  }
+}