// Copyright (c) 2012, 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:io';

import 'package:collection/collection.dart' show IterableExtension;
import 'package:path/path.dart' as p;
import 'package:pub_semver/pub_semver.dart';

import 'exceptions.dart';
import 'git.dart' as git;
import 'ignore.dart';
import 'io.dart';
import 'log.dart' as log;
import 'package_name.dart';
import 'pubspec.dart';
import 'source_registry.dart';
import 'utils.dart';

final _readmeRegexp = RegExp(r'^README($|\.)', caseSensitive: false);
final _changelogRegexp = RegExp(r'^CHANGELOG($|\.)', caseSensitive: false);

/// A named, versioned, unit of code and resource reuse.
class Package {
  /// Compares [a] and [b] orders them by name then version number.
  ///
  /// This is normally used as a [Comparator] to pass to sort. This does not
  /// take a package's description or root directory into account, so multiple
  /// distinct packages may order the same.
  static int orderByNameAndVersion(Package a, Package b) {
    var name = a.name.compareTo(b.name);
    if (name != 0) return name;

    return a.version.compareTo(b.version);
  }

  final String? _dir;

  /// The path to the directory containing the package.
  ///
  /// It is an error to access this on an in-memory package.
  String get dir {
    if (isInMemory) {
      throw UnsupportedError(
          'Package directory cannot be used for an in-memory package');
    }

    return _dir!;
  }

  /// An in-memory package can be created for doing a resolution without having
  /// a package on disk. Paths should not be resolved for these.
  bool get isInMemory => _dir == null;

  /// The name of the package.
  String get name => pubspec.name;

  /// The package's version.
  Version get version => pubspec.version;

  /// The parsed pubspec associated with this package.
  final Pubspec pubspec;

  /// The immediate dependencies this package specifies in its pubspec.
  Map<String, PackageRange> get dependencies => pubspec.dependencies;

  /// The immediate dev dependencies this package specifies in its pubspec.
  Map<String, PackageRange> get devDependencies => pubspec.devDependencies;

  /// The dependency overrides this package specifies in its pubspec.
  Map<String, PackageRange> get dependencyOverrides =>
      pubspec.dependencyOverrides;

  /// All immediate dependencies this package specifies.
  ///
  /// This includes regular, dev dependencies, and overrides.
  Map<String, PackageRange> get immediateDependencies {
    // Make sure to add overrides last so they replace normal dependencies.
    return {}
      ..addAll(dependencies)
      ..addAll(devDependencies)
      ..addAll(dependencyOverrides);
  }

  /// Returns a list of paths to all Dart executables in this package's bin
  /// directory.
  List<String> get executablePaths {
    final binDir = p.join(dir, 'bin');
    if (!dirExists(binDir)) return <String>[];
    return ordered(listDir(p.join(dir, 'bin'), includeDirs: false))
        .where((executable) => p.extension(executable) == '.dart')
        .map((executable) => p.relative(executable, from: dir))
        .toList();
  }

  List<String> get executableNames =>
      executablePaths.map(p.basenameWithoutExtension).toList();

  /// Returns the path to the README file at the root of the entrypoint, or null
  /// if no README file is found.
  ///
  /// If multiple READMEs are found, this uses the same conventions as
  /// pub.dartlang.org for choosing the primary one: the README with the fewest
  /// extensions that is lexically ordered first is chosen.
  String? get readmePath {
    var readmes = listFiles(recursive: false)
        .map(p.basename)
        .where((entry) => entry.contains(_readmeRegexp));
    if (readmes.isEmpty) return null;

    return p.join(dir, readmes.reduce((readme1, readme2) {
      var extensions1 = '.'.allMatches(readme1).length;
      var extensions2 = '.'.allMatches(readme2).length;
      var comparison = extensions1.compareTo(extensions2);
      if (comparison == 0) comparison = readme1.compareTo(readme2);
      return (comparison <= 0) ? readme1 : readme2;
    }));
  }

  /// Returns the path to the CHANGELOG file at the root of the entrypoint, or
  /// null if no CHANGELOG file is found.
  String? get changelogPath {
    return listFiles(recursive: false).firstWhereOrNull(
        (entry) => p.basename(entry).contains(_changelogRegexp));
  }

  /// Returns whether or not this package is in a Git repo.
  late final bool inGitRepo = computeInGitRepoCache();

  bool computeInGitRepoCache() {
    if (isInMemory || !git.isInstalled) {
      return false;
    } else {
      // If the entire package directory is ignored, don't consider it part of a
      // git repo. `git check-ignore` will return a status code of 0 for
      // ignored, 1 for not ignored, and 128 for not a Git repo.
      var result = runProcessSync(
          git.command!, ['check-ignore', '--quiet', '.'],
          workingDir: dir);
      return result.exitCode == 1;
    }
  }

  /// Loads the package whose root directory is [packageDir].
  ///
  /// [name] is the expected name of that package (e.g. the name given in the
  /// dependency), or `null` if the package being loaded is the entrypoint
  /// package.
  Package.load(String? name, String this._dir, SourceRegistry sources)
      : pubspec = Pubspec.load(_dir, sources, expectedName: name);

  /// Constructs a package with the given pubspec.
  ///
  /// The package will have no directory associated with it.
  Package.inMemory(this.pubspec) : _dir = null;

  /// Creates a package with [pubspec] located at [dir].
  Package(this.pubspec, String this._dir);

  /// Given a relative path within this package, returns its absolute path.
  ///
  /// This is similar to `p.join(dir, part1, ...)`, except that subclasses may
  /// override it to report that certain paths exist elsewhere than within
  /// [dir].
  String path(String? part1,
      [String? part2,
      String? part3,
      String? part4,
      String? part5,
      String? part6,
      String? part7]) {
    if (isInMemory) {
      throw StateError("Package $name is in-memory and doesn't have paths "
          'on disk.');
    }
    return p.join(dir, part1, part2, part3, part4, part5, part6, part7);
  }

  /// Given an absolute path within this package (such as that returned by
  /// [path] or [listFiles]), returns it relative to the package root.
  String relative(String path) {
    if (isInMemory) {
      throw StateError("Package $name is in-memory and doesn't have paths "
          'on disk.');
    }
    return p.relative(path, from: dir);
  }

  /// Returns the type of dependency from this package onto [name].
  DependencyType dependencyType(String? name) {
    if (pubspec.fields['dependencies']?.containsKey(name) ?? false) {
      return DependencyType.direct;
    } else if (pubspec.fields['dev_dependencies']?.containsKey(name) ?? false) {
      return DependencyType.dev;
    } else {
      return DependencyType.none;
    }
  }

  static final _basicIgnoreRules = [
    '.*', // Don't include dot-files.
    '!.htaccess', // Include .htaccess anyways.
    // TODO(sigurdm): consider removing this. `packages` folders are not used
    // anymore.
    'packages/',
    'pubspec.lock',
    '!pubspec.lock/', // We allow a directory called pubspec lock.
  ];

  /// Returns a list of files that are considered to be part of this package.
  ///
  /// If [beneath] is passed, this will only return files beneath that path,
  /// which is expected to be relative to the package's root directory. If
  /// [recursive] is true, this will return all files beneath that path;
  /// otherwise, it will only return files one level beneath it.
  ///
  /// This will take .pubignore and .gitignore files into account.
  ///
  /// If [dir] is inside a git repository, all ignore files from the repo root
  /// are considered.
  ///
  /// For each directory a .pubignore takes precedence over a .gitignore.
  ///
  /// Note that the returned paths won't always be beneath [dir]. To safely
  /// convert them to paths relative to the package root, use [relative].
  List<String> listFiles({String? beneath, bool recursive = true}) {
    // An in-memory package has no files.
    if (isInMemory) return [];

    var packageDir = dir;
    var root = git.repoRoot(packageDir) ?? packageDir;
    beneath = p
        .toUri(p.normalize(
            p.relative(p.join(packageDir, beneath ?? '.'), from: root)))
        .path;
    if (beneath == './') beneath = '.';
    String resolve(String path) {
      if (Platform.isWindows) {
        return p.joinAll([root, ...p.posix.split(path)]);
      }
      return p.join(root, path);
    }

    return Ignore.listFiles(
      beneath: beneath,
      listDir: (dir) {
        var contents = Directory(resolve(dir)).listSync();
        if (!recursive) {
          contents = contents.where((entity) => entity is! Directory).toList();
        }
        return contents.map((entity) {
          if (linkExists(entity.path)) {
            final target = Link(entity.path).targetSync();
            if (dirExists(entity.path)) {
              throw DataException(
                  '''Pub does not support publishing packages with directory symlinks: `${entity.path}`.''');
            }
            if (!fileExists(entity.path)) {
              throw DataException(
                  '''Pub does not support publishing packages with non-resolving symlink: `${entity.path}` => `$target`.''');
            }
          }
          final relative = p.relative(entity.path, from: root);
          if (Platform.isWindows) {
            return p.posix.joinAll(p.split(relative));
          }
          return relative;
        });
      },
      ignoreForDir: (dir) {
        final pubIgnore = resolve('$dir/.pubignore');
        final gitIgnore = resolve('$dir/.gitignore');
        final ignoreFile = fileExists(pubIgnore)
            ? pubIgnore
            : (fileExists(gitIgnore) ? gitIgnore : null);

        final rules = [
          if (dir == beneath) ..._basicIgnoreRules,
          if (ignoreFile != null) readTextFile(ignoreFile),
        ];
        return rules.isEmpty
            ? null
            : Ignore(
                rules,
                onInvalidPattern: (pattern, exception) {
                  log.warning(
                      '$ignoreFile had invalid pattern $pattern. ${exception.message}');
                },
                // Ignore case on MacOs and Windows, because `git clone` and
                // `git init` will set `core.ignoreCase = true` in the local
                // local `.git/config` file for the repository.
                //
                // So on Windows and MacOS most users will have case-insensitive
                // behavior with `.gitignore`, hence, it seems reasonable to do
                // the same when we interpret `.gitignore` and `.pubignore`.
                //
                // There are cases where a user may have case-sensitive behavior
                // with `.gitignore` on Windows and MacOS:
                //
                //  (A) The user has manually overwritten the repository
                //      configuration setting `core.ignoreCase = false`.
                //
                //  (B) The git-clone or git-init command that create the
                //      repository did not deem `core.ignoreCase = true` to be
                //      appropriate. Documentation for [git-config]][1] implies
                //      this might depend on whether or not the filesystem is
                //      case sensitive:
                //      > If true, this option enables various workarounds to
                //      > enable Git to work better on filesystems that are not
                //      > case sensitive, like FAT.
                //      > ...
                //      > The default is false, except git-clone[1] or
                //      > git-init[1] will probe and set core.ignoreCase true
                //      > if appropriate when the repository is created.
                //
                // In either case, it seems likely that users on Windows and
                // MacOS will prefer case-insensitive matching. We specifically
                // know that some tooling will generate `.PDB` files instead of
                // `.pdb`, see: [#3003][2]
                //
                // [1]: https://git-scm.com/docs/git-config/2.14.6#Documentation/git-config.txt-coreignoreCase
                // [2]: https://github.com/dart-lang/pub/issues/3003
                ignoreCase: Platform.isMacOS || Platform.isWindows,
              );
      },
      isDir: (dir) => dirExists(resolve(dir)),
    ).map(resolve).toList();
  }
}

/// The type of dependency from one package to another.
class DependencyType {
  /// A dependency declared in `dependencies`.
  static const direct = DependencyType._('direct');

  /// A dependency declared in `dev_dependencies`.
  static const dev = DependencyType._('dev');

  /// No dependency exists.
  static const none = DependencyType._('none');

  final String _name;

  const DependencyType._(this._name);

  @override
  String toString() => _name;
}