// 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.

library polymer.test.build.common;

import 'dart:async';

import 'package:barback/barback.dart';
import 'package:stack_trace/stack_trace.dart';
import 'package:unittest/unittest.dart';

String idToString(AssetId id) => '${id.package}|${id.path}';
AssetId idFromString(String s) {
  int index = s.indexOf('|');
  return new AssetId(s.substring(0, index), s.substring(index + 1));
}

String _removeTrailingWhitespace(String str) =>
    str.splitMapJoin('\n',
        onNonMatch: (s) => s.replaceAll(new RegExp(r'\s+$'), ''));

/// A helper package provider that has files stored in memory, also wraps
/// [Barback] to simply our tests.
class TestHelper implements PackageProvider {
  /// Maps from an asset string identifier of the form 'package|path' to the
  /// file contents.
  final Map<String, String> files;
  final Iterable<String> packages;
  final List<String> messages;
  int messagesSeen = 0;
  bool errorSeen = false;

  Barback barback;
  var errorSubscription;
  var resultSubscription;
  var logSubscription;

  Future<Asset> getAsset(AssetId id) {
    var content = files[idToString(id)];
    if (content == null) fail('error: requested $id, but $id is not available');
    return new Future.value(new Asset.fromString(id, content));
  }

  TestHelper(List<List<Transformer>> transformers, Map<String, String> files,
      this.messages)
      : files = files,
        packages = files.keys.map((s) => idFromString(s).package) {
    barback = new Barback(this);
    for (var p in packages) {
      barback.updateTransformers(p, transformers);
    }

    errorSubscription = barback.errors.listen((e) {
      var trace = null;
      if (e is Error) trace = e.stackTrace;
      if (trace != null) {
        print(Trace.format(trace));
      }
      fail('error running barback: $e');
    });

    resultSubscription = barback.results.listen((result) {
      expect(result.succeeded, !errorSeen, reason: "${result.errors}");
    });

    logSubscription = barback.log.listen((entry) {
      // Ignore info messages.
      if (entry.level == LogLevel.INFO) return;
      if (entry.level == LogLevel.ERROR) errorSeen = true;
      // We only check messages when an expectation is provided.
      if (messages == null) return;

      var msg = '${entry.level.name.toLowerCase()}: ${entry.message}';
      var span = entry.span;
      var spanInfo = span == null ? '' :
          ' (${span.sourceUrl} ${span.start.line} ${span.start.column})';
      expect(messagesSeen, lessThan(messages.length),
          reason: 'more messages than expected.\nMessage seen: $msg$spanInfo');
      expect('$msg$spanInfo', messages[messagesSeen++]);
    });
  }

  void tearDown() {
    errorSubscription.cancel();
    resultSubscription.cancel();
    logSubscription.cancel();
  }

  /// Tells barback which files have changed, and thus anything that depends on
  /// it on should be computed. By default mark all the input files.
  void run([Iterable<String> paths]) {
    if (paths == null) paths = files.keys;
    barback.updateSources(paths.map(idFromString));
  }

  Future<String> operator [](String assetString){
    return barback.getAssetById(idFromString(assetString))
        .then((asset) => asset.readAsString());
  }

  Future check(String assetIdString, String content) {
    return this[assetIdString].then((value) {
      value = _removeTrailingWhitespace(value);
      content = _removeTrailingWhitespace(content);
      expect(value, content, reason: 'Final output of $assetIdString differs.');
    });
  }

  Future checkAll(Map<String, String> files) {
    return barback.results.first.then((_) {
      if (files == null) return null;
      var futures = [];
      files.forEach((k, v) {
        futures.add(check(k, v));
      });
      return Future.wait(futures);
    }).then((_) {
      // We only check messages when an expectation is provided.
      if (messages == null) return;
      expect(messages.length, messagesSeen,
          reason: 'less messages than expected');
    });
  }
}

testPhases(String testName, List<List<Transformer>> phases,
    Map<String, String> inputFiles, Map<String, String> expectedFiles,
    [List<String> expectedMessages, bool solo = false]) {

  // Include mock versions of the polymer library that can be used to test
  // resolver-based code generation.
  POLYMER_MOCKS.forEach((file, contents) { inputFiles[file] = contents; });
  (solo ? solo_test : test)(testName, () {
    var helper = new TestHelper(phases, inputFiles, expectedMessages)..run();
    return helper.checkAll(expectedFiles).whenComplete(() => helper.tearDown());
  });
}

solo_testPhases(String testName, List<List<Transformer>> phases,
    Map<String, String> inputFiles, Map<String, String> expectedFiles,
    [List<String> expectedMessages]) =>
  testPhases(testName, phases, inputFiles, expectedFiles, expectedMessages,
      true);

/// Generate an expected ._data file, where all files are assumed to be in the
/// same [package].
String expectedData(List<String> urls, {package: 'a', experimental: false}) {
  var ids = urls.map((e) => '["$package","$e"]').join(',');
  return '{"experimental_bootstrap":$experimental,"script_ids":[$ids]}';
}

const EMPTY_DATA = '{"experimental_bootstrap":false,"script_ids":[]}';

const WEB_COMPONENTS_TAG =
    '<script src="packages/web_components/platform.js"></script>\n'
    '<script src="packages/web_components/dart_support.js"></script>\n';

const INTEROP_TAG = '<script src="packages/browser/interop.js"></script>\n';
const DART_JS_TAG = '<script src="packages/browser/dart.js"></script>';

const POLYMER_MOCKS = const {
  'polymer|lib/polymer.html': '<!DOCTYPE html><html>',
  'polymer|lib/polymer_experimental.html': '<!DOCTYPE html><html>',
  'polymer|lib/polymer.dart':
      'library polymer;\n'
      'import "dart:html";\n'
      'export "package:observe/observe.dart";\n' // for @observable
      'part "src/loader.dart";\n'  // for @CustomTag and @initMethod
      'part "src/instance.dart";\n', // for @published and @ObserveProperty

  'polymer|lib/src/loader.dart':
      'part of polymer;\n'
      'class CustomTag {\n'
      '  final String tagName;\n'
      '  const CustomTag(this.tagName);'
      '}\n'
      'class InitMethodAnnotation { const InitMethodAnnotation(); }\n'
      'const initMethod = const InitMethodAnnotation();\n',

  'polymer|lib/src/instance.dart':
      'part of polymer;\n'
      'class PublishedProperty { const PublishedProperty(); }\n'
      'const published = const PublishedProperty();\n'
      'class ObserveProperty { const ObserveProperty(); }\n'
      'abstract class Polymer {}\n'
      'class PolymerElement extends HtmlElement with Polymer {}\n',

  'polymer|lib/init.dart':
      'library polymer.init;\n'
      'import "package:polymer/polymer.dart";\n'
      'main() {};\n',

  'observe|lib/observe.dart':
      'library observe;\n'
      'export "src/metadata.dart";',

  'observe|lib/src/metadata.dart':
      'library observe.src.metadata;\n'
      'class ObservableProperty { const ObservableProperty(); }\n'
      'const observable = const ObservableProperty();\n',
};