// 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" show Future;
import "dart:convert" show utf8;
import "dart:io" show File;

import 'package:package_config/packages_file.dart' as packages_file;
import 'package:path/path.dart' as p;
import 'package:pub_semver/pub_semver.dart';
import 'package:test/test.dart';
import 'package:test_descriptor/test_descriptor.dart';

import '../test_pub.dart';

/// Describes a `.packages` file and its contents.
class PackagesFileDescriptor extends Descriptor {
  /// A map from package names to strings describing where the packages are
  /// located on disk.
  final Map<String, String> _dependencies;

  /// Describes a `.packages` file with the given dependencies.
  ///
  /// [dependencies] maps package names to strings describing where the packages
  /// are located on disk.
  PackagesFileDescriptor([this._dependencies]) : super('.packages');

  Future create([String parent]) {
    var contents = const <int>[];
    if (_dependencies != null) {
      var mapping = <String, Uri>{};
      _dependencies.forEach((package, version) {
        String packagePath;
        if (_isSemver(version)) {
          // It's a cache reference.
          packagePath = p.join(cachePath, "$package-$version");
        } else {
          // Otherwise it's a path relative to the pubspec file,
          // which is also relative to the .packages file.
          packagePath = p.fromUri(version);
        }
        mapping[package] = p.toUri(p.join(packagePath, "lib", ""));
      });
      var buffer = StringBuffer();
      packages_file.write(buffer, mapping);
      contents = utf8.encode(buffer.toString());
    }
    return File(p.join(parent ?? sandbox, name)).writeAsBytes(contents);
  }

  Future validate([String parent]) async {
    var fullPath = p.join(parent ?? sandbox, name);
    if (!await File(fullPath).exists()) {
      fail("File not found: '$fullPath'.");
    }

    var bytes = await File(fullPath).readAsBytes();

    // Resolve against a dummy URL so that we can test whether the URLs in
    // the package file are themselves relative. We can't resolve against just
    // "." due to sdk#23809.
    var base = "/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p";
    var map = packages_file.parse(bytes, Uri.parse(base));

    for (var package in _dependencies.keys) {
      if (!map.containsKey(package)) {
        fail(".packages does not contain $package entry");
      }

      var description = _dependencies[package];
      if (_isSemver(description)) {
        if (!map[package].path.contains(description)) {
          fail(".packages of $package has incorrect version. "
              "Expected $description, found location: ${map[package]}.");
        }
      } else {
        var expected = p.normalize(p.join(p.fromUri(description), 'lib'));
        var actual = p.normalize(p.fromUri(
            p.url.relative(map[package].toString(), from: p.dirname(base))));

        if (expected != actual) {
          fail("Relative path: Expected $expected, found $actual");
        }
      }
    }

    if (map.length != _dependencies.length) {
      for (var key in map.keys) {
        if (!_dependencies.containsKey(key)) {
          fail(".packages file contains unexpected entry: $key");
        }
      }
    }
  }

  /// Returns `true` if [text] is a valid semantic version number string.
  bool _isSemver(String text) {
    try {
      // See if it's a semver.
      Version.parse(text);
      return true;
    } on FormatException catch (_) {
      // Do nothing.
    }
    return false;
  }

  String describe() => name;
}