import 'package:flutter_test/flutter_test.dart';
import 'package:life_helper/data/ai/device_capabilities.dart';

/// #218 AC-6 boundary tests for the RAM gate.
///
/// We test the abstract contract's `meetsAiMinRam()` default impl via a
/// fake — the real `PlatformDeviceCapabilities.totalRamBytes()` requires
/// the MethodChannel + Android runtime (covered by AC-7).
class _Fake implements DeviceCapabilities {
  _Fake(this.bytes);
  final int? bytes;

  @override
  Future<int?> totalRamBytes() async => bytes;

  @override
  Future<bool> meetsAiMinRam() async {
    final v = await totalRamBytes();
    if (v == null) return false;
    return v >= kAiMinRamBytes;
  }
}

void main() {
  test('kAiMinRamBytes equals 4 GiB', () {
    expect(kAiMinRamBytes, 4 * 1024 * 1024 * 1024);
  });

  test('null totalRamBytes → meetsAiMinRam false (fail-closed)', () async {
    expect(await _Fake(null).meetsAiMinRam(), isFalse);
  });

  test('3.9 GiB → meetsAiMinRam false', () async {
    final bytes = (3.9 * 1024 * 1024 * 1024).round();
    expect(await _Fake(bytes).meetsAiMinRam(), isFalse);
  });

  test('exactly 4 GiB - 1 byte → false', () async {
    expect(await _Fake(kAiMinRamBytes - 1).meetsAiMinRam(), isFalse);
  });

  test('exactly 4 GiB → true (inclusive)', () async {
    expect(await _Fake(kAiMinRamBytes).meetsAiMinRam(), isTrue);
  });

  test('8 GiB → true', () async {
    final bytes = 8 * 1024 * 1024 * 1024;
    expect(await _Fake(bytes).meetsAiMinRam(), isTrue);
  });

  test('0 bytes → false (would also catch broken channel returning 0)', () async {
    expect(await _Fake(0).meetsAiMinRam(), isFalse);
  });
}