// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'package:barback/barback.dart';
import 'package:observe/transform.dart';
import 'package:unittest/compact_vm_config.dart';
import 'package:unittest/unittest.dart';

main() {
  useCompactVMConfiguration();

  group('replaces Observable for ChangeNotifier', () {
    _testClause('extends ObservableBase', 'extends ChangeNotifierBase');
    _testClause('extends Base with ObservableMixin',
        'extends Base with ChangeNotifierMixin');
    _testClause('extends Base<T> with ObservableMixin',
        'extends Base<T> with ChangeNotifierMixin');
    _testClause('extends Base with Mixin, ObservableMixin',
        'extends Base with Mixin, ChangeNotifierMixin');
    _testClause('extends Base with ObservableMixin, Mixin',
        'extends Base with ChangeNotifierMixin, Mixin');
    _testClause('extends Base with Mixin<T>, ObservableMixin',
        'extends Base with Mixin<T>, ChangeNotifierMixin');
    _testClause('extends Base with Mixin, ObservableMixin, Mixin2',
        'extends Base with Mixin, ChangeNotifierMixin, Mixin2');
    _testClause('extends ObservableBase implements Interface',
        'extends ChangeNotifierBase implements Interface');
    _testClause('extends ObservableBase implements Interface<T>',
        'extends ChangeNotifierBase implements Interface<T>');
    _testClause('extends Base with ObservableMixin implements Interface',
        'extends Base with ChangeNotifierMixin implements Interface');
    _testClause(
        'extends Base with Mixin, ObservableMixin implements I1, I2',
        'extends Base with Mixin, ChangeNotifierMixin implements I1, I2');
  });

  group('fixes contructor calls ', () {
    _testInitializers('this.a', '(a) : __\$a = a');
    _testInitializers('{this.a}', '({a}) : __\$a = a');
    _testInitializers('[this.a]', '([a]) : __\$a = a');
    _testInitializers('this.a, this.b', '(a, b) : __\$a = a, __\$b = b');
    _testInitializers('{this.a, this.b}', '({a, b}) : __\$a = a, __\$b = b');
    _testInitializers('[this.a, this.b]', '([a, b]) : __\$a = a, __\$b = b');
    _testInitializers('this.a, [this.b]', '(a, [b]) : __\$a = a, __\$b = b');
    _testInitializers('this.a, {this.b}', '(a, {b}) : __\$a = a, __\$b = b');
  });

  group('test full text', () {
    test('with changes', () {
      return _transform(_sampleObservable('A', 'foo'))
        .then((output) => expect(output, _sampleObservableOutput('A', 'foo')));
    });

    test('no changes', () {
      var input = 'class A {/*@observable annotation to trigger transform */;}';
      return _transform(input).then((output) => expect(output, input));
    });
  });
}

_testClause(String clauses, String expected) {
  test(clauses, () {
    var className = 'MyClass';
    if (clauses.contains('<T>')) className += '<T>';
    var code = '''
      class $className $clauses {
        @observable var field;
      }''';

    return _transform(code).then((output) {
      var classPos = output.indexOf(className) + className.length;
      var actualClauses = output.substring(classPos,
        output.indexOf('{')).trim().replaceAll('  ', ' ');
      expect(actualClauses, expected);
    });
  });
}

_testInitializers(String args, String expected) {
  test(args, () {
    var constructor = 'MyClass(';
    var code = '''
        class MyClass {
          @observable var a;
          @observable var b;
          MyClass($args);
        }''';

    return _transform(code).then((output) {
      var begin = output.indexOf(constructor) + constructor.length - 1;
      var end = output.indexOf(';', begin);
      if (end == -1) end = output.length;
      var init = output.substring(begin, end).trim().replaceAll('  ', ' ');
      expect(init, expected);
    });
  });
}

/** Helper that applies the transform by creating mock assets. */
Future<String> _transform(String code) {
  var id = new AssetId('foo', 'a/b/c.dart');
  var asset = new Asset.fromString(id, code);
  var transformer = new ObservableTransformer();
  return transformer.isPrimary(asset).then((isPrimary) {
    expect(isPrimary, isTrue);
    var transform = new _MockTransform(asset);
    return transformer.apply(transform).then((_) {
      expect(transform.outs, hasLength(1));
      expect(transform.outs[0].id, id);
      return transform.outs.first.readAsString();
    });
  });
}

class _MockTransform implements Transform {
  List<Asset> outs = [];
  Asset _asset;
  TransformLogger logger = new TransformLogger(false);
  Asset get primaryInput => _asset;

  _MockTransform(this._asset);
  Future<Asset> getInput(Asset id) {
    if (id == primaryInput.id) return new Future.value(primaryInput);
    fail();
  }

  void addOutput(Asset output) {
    outs.add(output);
  }
}

String _sampleObservable(String className, String fieldName) => '''
library ${className}_$fieldName;
import 'package:observe/observe.dart';

class $className extends ObservableBase {
  @observable int $fieldName;
  $className(this.$fieldName);
}
''';

String _sampleObservableOutput(String className, String fieldName) => '''
library ${className}_$fieldName;
import 'package:observe/observe.dart';

class $className extends ChangeNotifierBase {
  int __\$$fieldName;
  int get $fieldName => __\$$fieldName;
  set $fieldName(int value) {
    __\$$fieldName = notifyPropertyChange(const Symbol('$fieldName'), __\$$fieldName, value);
  }
  
  $className($fieldName) : __\$$fieldName = $fieldName;
}
''';