import 'dart:convert';
import 'dart:io';

import 'package:crypto/crypto.dart' show sha256;
import 'package:flutter_test/flutter_test.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';
import 'package:observer/models/model_manager.dart';

const _modelBytes = [1, 2, 3, 4, 5, 6, 7, 8];

String _shaHex(List<int> bytes) => sha256.convert(bytes).toString();

Map<String, dynamic> _catalog(List<Map<String, dynamic>> models) =>
    {'code': 0, 'message': 'ok', 'data': {'version': '0.0.2', 'notes': '', 'models': models}};

Map<String, dynamic> _item({String version = 'v1.0.0', String sha = ''}) => {
      'datasetId': 7,
      'datasetName': '野鸡数据集',
      'version': version,
      'labels': ['pheasant', 'suspect'],
      'sizeBytes': _modelBytes.length,
      'sha256': sha.isEmpty ? _shaHex(_modelBytes) : sha,
      'downloadUrl': '/download/models/野鸡数据集/latest.tflite',
    };

void main() {
  late Directory root;
  late int downloadHits;

  setUp(() async {
    root = await Directory.systemTemp.createTemp('model-manager-test');
    downloadHits = 0;
  });

  tearDown(() => root.delete(recursive: true));

  ModelManager manager(MockClient client) => ModelManager(
        baseUrl: 'http://test.local',
        client: client,
        rootDir: () async => root,
      );

  MockClient client(List<Map<String, dynamic>> models) => MockClient((req) async {
        if (req.url.path == '/api/v1/app/update') {
          // Response(String) 默认 latin1 编码，中文数据集名会抛异常 → 用 bytes
          return http.Response.bytes(utf8.encode(jsonEncode(_catalog(models))), 200);
        }
        if (req.url.path.startsWith('/download/models/')) {
          downloadHits++;
          return http.Response.bytes(_modelBytes, 200);
        }
        return http.Response('not found', 404);
      });

  test('首次拉取：下载模型并落盘（model/labels/meta）', () async {
    final m = manager(client([_item()]));
    await m.refresh();

    expect(m.ready, isTrue);
    expect(m.error, isNull);
    expect(m.models.length, 1);
    expect(m.models.first.datasetName, '野鸡数据集');
    expect(m.models.first.bytes, _modelBytes);
    expect(downloadHits, 1);

    final dir = Directory('${root.path}/7');
    expect(await File('${dir.path}/model.tflite').exists(), isTrue);
    expect(await File('${dir.path}/labels.json').exists(), isTrue);
    expect(await File('${dir.path}/meta.json').exists(), isTrue);
  });

  test('版本未变不重复下载（meta 命中直接跳过）', () async {
    final m = manager(client([_item()]));
    await m.refresh();
    expect(downloadHits, 1);

    await m.refresh();
    expect(downloadHits, 1, reason: 'meta 匹配应跳过下载');
    expect(m.models.length, 1);
  });

  test('版本更新触发重新下载', () async {
    final m = manager(client([_item()]));
    await m.refresh();
    expect(downloadHits, 1);

    await m.refresh();
    expect(downloadHits, 1);

    // 发布新版本：再次刷新应重下
    await m.refresh();
    expect(downloadHits, 1);
    // 上面三次同一版本，重新构造带新版本的 manager（同一 root）
    final m2 = manager(client([_item(version: 'v2.0.0')]));
    await m2.refresh();
    expect(downloadHits, 2);
    expect(m2.models.first.version, 'v2.0.0');
  });

  test('sha256 不匹配：重试后失败，保留旧模型并报错', () async {
    // 第一次下载成功（sha 匹配）
    final m1 = manager(client([_item()]));
    await m1.refresh();
    expect(m1.models.length, 1);

    // 服务器 sha 与文件不符（被篡改/损坏）→ 下载校验失败
    final bad = _item(version: 'v3.0.0');
    bad['sha256'] = _shaHex([9, 9, 9]);
    final m2 = manager(client([bad]));
    await m2.refresh();

    expect(m2.models.length, 0, reason: '校验失败的模型不应加载');
    expect(m2.error, isNotNull);
    expect(m2.error, contains('野鸡数据集'));
  });

  test('目录下线：清理本地并清空模型', () async {
    final m = manager(client([_item()]));
    await m.refresh();
    expect(m.models.length, 1);
    expect(await Directory('${root.path}/7').exists(), isTrue);

    final m2 = manager(client([]));
    await m2.refresh();
    expect(m2.models, isEmpty);
    expect(await Directory('${root.path}/7').exists(), isFalse,
        reason: '下线的数据集模型目录应被清理');
  });

  test('目录接口异常：不覆盖已有就绪状态', () async {
    final m = manager(client([_item()]));
    await m.refresh();
    expect(m.ready, isTrue);

    final broken = manager(MockClient((_) async => http.Response('boom', 500)));
    await broken.refresh();
    expect(broken.ready, isFalse);
    expect(broken.error, isNotNull);
  });
}