import 'dart:typed_data';

import 'package:eaimar/data/services/wav_writer.dart';
import 'package:flutter_test/flutter_test.dart';

Uint8List _bytes(int n, int fill) => Uint8List.fromList(List.filled(n, fill));

void main() {
  test('两路顺序到达：逐对取出，谁都不丢', () {
    final p = StereoPairer();
    p.pushLeft(_bytes(640, 1));
    expect(p.take(), isNull); // 只有一路时不出对
    p.pushRight(_bytes(640, 2));
    final pair = p.take()!;
    expect(pair.left.length, 640);
    expect(pair.right.length, 640);
    expect(pair.left.first, 1);
    expect(pair.right.first, 2);
    expect(p.take(), isNull);
  });

  test('对端连来两帧、本端才来一帧：第一帧不再被覆盖丢掉', () {
    final p = StereoPairer();
    p.pushRight(_bytes(640, 2));
    p.pushRight(_bytes(640, 3));
    p.pushLeft(_bytes(640, 1));
    final first = p.take()!;
    expect(first.right.first, 2); // 老实现这里会拿到 3（第一帧被覆盖）
    expect(p.take(), isNull);
    p.pushLeft(_bytes(640, 1));
    final second = p.take()!;
    expect(second.right.first, 3);
  });

  test('长度不等时按较短者对齐到整样本，余量留到下一次', () {
    final p = StereoPairer();
    p.pushLeft(_bytes(1000, 1));
    p.pushRight(_bytes(301, 2));
    final a = p.take()!;
    expect(a.left.length, 300);
    expect(a.right.length, 300);
    p.pushRight(_bytes(699, 2));
    final b = p.take()!;
    expect(b.left.length, 700);
    expect(b.right.length, 700);
  });

  test('一路长期缺席：另一路只保留最近 maxPending 字节', () {
    final p = StereoPairer(maxPending: 1000);
    for (var i = 0; i < 5; i++) {
      p.pushLeft(_bytes(640, i));
    }
    p.pushRight(_bytes(1000, 9));
    final pair = p.take()!;
    expect(pair.left.length, 1000);
    expect(pair.left.last, 4); // 留下的是最新的那一段
  });
}