// ignore_for_file: avoid_print

import 'dart:io';
import 'dart:typed_data';

import 'package:aves/services/cast/cast_fmp4_fragment_parser.dart';

Future<void> main(List<String> arguments) async {
  final sourcePath = arguments.isNotEmpty ? arguments.first : 'stream_test.fmp4';

  final sourceFile = File(sourcePath);

  if (!await sourceFile.exists()) {
    throw StateError(
      'File fMP4 non trovato: ${sourceFile.absolute.path}',
    );
  }

  const maximumFragments = 5;
  const parser = CastFmp4FragmentParser();

  final source = await sourceFile.open(
    mode: FileMode.read,
  );

  final fileLength = await source.length();

  final decodeTimes = <int, int>{
    1: 0,
    2: 0,
  };

  var offset = 0;
  var fragmentIndex = 0;
  _BoxInfo? pendingMoof;

  try {
    while (offset + 8 <= fileLength && fragmentIndex < maximumFragments) {
      final box = await _readBox(
        source: source,
        offset: offset,
        fileLength: fileLength,
      );

      if (box == null) {
        break;
      }

      if (box.type == 'moof') {
        if (pendingMoof != null) {
          throw StateError(
            'Nuovo moof prima del relativo mdat: '
            'offset=${box.offset}',
          );
        }

        pendingMoof = box;
      } else if (box.type == 'mdat') {
        final moof = pendingMoof;

        if (moof == null) {
          throw StateError(
            'mdat senza moof: offset=${box.offset}',
          );
        }

        if (moof.end != box.offset) {
          throw StateError(
            'moof e mdat non adiacenti: '
            'moofEnd=${moof.end} '
            'mdatOffset=${box.offset}',
          );
        }

        final moofBytes = await _readRange(
          source: source,
          offset: moof.offset,
          length: moof.size,
        );

        final initialDecodeTimes = Map<int, int>.from(decodeTimes);

        final fragment = parser.parse(
          moofBytes: moofBytes,
          moofOffset: moof.offset,
          mdatOffset: box.offset,
          mdatSize: box.size,
          mdatHeaderSize: box.headerSize,
          initialDecodeTimes: initialDecodeTimes,
        );

        print('');
        print(
          'FRAGMENT '
          'index=$fragmentIndex '
          'moofOffset=${fragment.moofOffset} '
          'moofSize=${fragment.moofSize} '
          'mdatOffset=${fragment.mdatOffset} '
          'mdatSize=${fragment.mdatSize}',
        );

        for (final track in fragment.tracks) {
          final expectedInitial = initialDecodeTimes[track.trackId] ?? 0;

          if (track.initialDecodeTime != expectedInitial) {
            throw StateError(
              'DTS iniziale inatteso: '
              'fragment=$fragmentIndex '
              'track=${track.trackId} '
              'actual=${track.initialDecodeTime} '
              'expected=$expectedInitial',
            );
          }

          if (track.samples.isEmpty) {
            throw StateError(
              'Track senza sample: '
              'fragment=$fragmentIndex '
              'track=${track.trackId}',
            );
          }

          if (track.samples.first.decodeTime != expectedInitial) {
            throw StateError(
              'Primo sample con DTS inatteso: '
              'fragment=$fragmentIndex '
              'track=${track.trackId}',
            );
          }

          decodeTimes[track.trackId] = track.nextDecodeTime;

          print(
            'TRACK '
            'trackId=${track.trackId} '
            'samples=${track.sampleCount} '
            'initialDts=${track.initialDecodeTime} '
            'nextDts=${track.nextDecodeTime} '
            'duration=${track.totalDuration} '
            'bytes=${track.totalSampleBytes} '
            'syncSamples=${track.syncSampleCount} '
            'firstOffset=${track.firstSampleAbsoluteOffset}',
          );
        }

        final audio = fragment.tracks.singleWhere(
          (track) => track.trackId == 1,
        );

        final video = fragment.tracks.singleWhere(
          (track) => track.trackId == 2,
        );

        if (video.sampleCount != 90) {
          throw StateError(
            'Numero frame video inatteso: '
            'fragment=$fragmentIndex '
            'actual=${video.sampleCount} '
            'expected=90',
          );
        }

        if (video.totalDuration != 270000) {
          throw StateError(
            'Durata video inattesa: '
            'fragment=$fragmentIndex '
            'actual=${video.totalDuration} '
            'expected=270000',
          );
        }

        if (video.syncSampleCount < 1) {
          throw StateError(
            'Frammento video senza keyframe: '
            'fragment=$fragmentIndex',
          );
        }

        if (!video.samples.first.isSync) {
          throw StateError(
            'Il frammento non inizia con un keyframe: '
            'fragment=$fragmentIndex',
          );
        }

        if (audio.totalDuration <= 0) {
          throw StateError(
            'Durata audio non valida: '
            'fragment=$fragmentIndex',
          );
        }

        pendingMoof = null;
        fragmentIndex++;
      }

      offset = box.end;
    }
  } finally {
    await source.close();
  }

  if (fragmentIndex != maximumFragments) {
    throw StateError(
      'Frammenti analizzati insufficienti: '
      'actual=$fragmentIndex '
      'expected=$maximumFragments',
    );
  }

  print('');
  print(
    'FINAL DECODE TIMES '
    'audio=${decodeTimes[1]} '
    'video=${decodeTimes[2]}',
  );

  print(
    'FMP4 MULTIPLE FRAGMENTS TEST: PASS '
    'fragments=$fragmentIndex',
  );
}

Future<_BoxInfo?> _readBox({
  required RandomAccessFile source,
  required int offset,
  required int fileLength,
}) async {
  if (fileLength - offset < 8) {
    return null;
  }

  await source.setPosition(offset);

  final header = await source.read(8);

  if (header.length != 8) {
    return null;
  }

  final data = ByteData.sublistView(
    Uint8List.fromList(header),
  );

  final size32 = data.getUint32(
    0,
    Endian.big,
  );

  final type = String.fromCharCodes(
    header.sublist(4, 8),
  );

  var headerSize = 8;
  int size;

  if (size32 == 1) {
    final extended = await source.read(8);

    if (extended.length != 8) {
      return null;
    }

    size =
        ByteData.sublistView(
          Uint8List.fromList(extended),
        ).getUint64(
          0,
          Endian.big,
        );

    headerSize = 16;
  } else if (size32 == 0) {
    size = fileLength - offset;
  } else {
    size = size32;
  }

  if (size < headerSize) {
    throw StateError(
      'Dimensione box non valida: '
      'offset=$offset '
      'type=$type '
      'size=$size',
    );
  }

  if (offset + size > fileLength) {
    return null;
  }

  return _BoxInfo(
    type: type,
    offset: offset,
    size: size,
    headerSize: headerSize,
  );
}

Future<Uint8List> _readRange({
  required RandomAccessFile source,
  required int offset,
  required int length,
}) async {
  await source.setPosition(offset);

  final bytes = await source.read(length);

  if (bytes.length != length) {
    throw StateError(
      'Lettura incompleta: '
      'offset=$offset '
      'actual=${bytes.length} '
      'expected=$length',
    );
  }

  return Uint8List.fromList(bytes);
}

class _BoxInfo {
  final String type;
  final int offset;
  final int size;
  final int headerSize;

  const _BoxInfo({
    required this.type,
    required this.offset,
    required this.size,
    required this.headerSize,
  });

  int get end => offset + size;
}