// Copyright (c) 2023, 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:firehose/src/repo.dart';

import 'src/github.dart';
import 'src/pub.dart';
import 'src/utils.dart';

const String _botSuffix = '[bot]';

const String _githubActionsUser = 'github-actions[bot]';

const String _publishBotTag = '## Package publishing';

class Firehose {
  final Directory directory;

  Firehose(this.directory);

  /// Validate the packages in the repository.
  ///
  /// This method is intended to run in the context of a PR. It will:
  /// - determine the set of packages in the repo
  /// - validate that the changelog version == the pubspec version
  /// - provide feedback on the PR (via a PR comment) about packages which are
  ///   ready to publish
  Future<void> validate() async {
    var github = Github();

    // Do basic validation of our expected env var.
    if (!_expectEnv(github.githubAuthToken, 'GITHUB_TOKEN')) return;
    if (!_expectEnv(github.repoSlug, 'GITHUB_REPOSITORY')) return;
    if (!_expectEnv(github.issueNumber, 'ISSUE_NUMBER')) return;
    if (!_expectEnv(github.sha, 'GITHUB_SHA')) return;

    if ((github.actor ?? '').endsWith(_botSuffix)) {
      print('Skipping package validation for ${github.actor} PRs.');
      return;
    }

    var results = await _validate(github);

    var markdownTable = '''
| Package | Version | Status | Publish tag |
| :--- | ---: | :--- | ---: |
${results.describeAsMarkdown}

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.
''';

    // Write the publish info status to the job summary.
    github.appendStepSummary(markdownTable);

    var existingCommentId = await allowFailure(
      github.findCommentId(
        github.repoSlug!,
        github.issueNumber!,
        user: _githubActionsUser,
        searchTerm: _publishBotTag,
      ),
      logError: print,
    );

    if (results.hasSuccess) {
      var commentText = '$_publishBotTag\n\n$markdownTable';

      if (existingCommentId == null) {
        await allowFailure(
          github.createComment(
              github.repoSlug!, github.issueNumber!, commentText),
          logError: print,
        );
      } else {
        await allowFailure(
          github.updateComment(
              github.repoSlug!, existingCommentId, commentText),
          logError: print,
        );
      }
    } else {
      if (results.hasError && exitCode == 0) {
        exitCode = 1;
      }

      if (existingCommentId != null) {
        await allowFailure(
          github.deleteComment(github.repoSlug!, existingCommentId),
          logError: print,
        );
      }
    }

    github.close();
  }

  Future<VerificationResults> _validate(Github github) async {
    var repo = Repository();
    var packages = repo.locatePackages();

    var pub = Pub();

    var results = VerificationResults();

    for (var package in packages) {
      var repoTag = repo.calculateRepoTag(package);

      print('');
      print('Validating $package:${package.name}');

      print('pubspec:');
      var pubspecVersion = package.pubspec.version;
      if (pubspecVersion == null) {
        var result = Result.fail(
          package,
          "no version specified (perhaps you need a' publish_to: none' entry?)",
        );
        print(result);
        results.addResult(result);
        continue;
      }
      print('  - version: $pubspecVersion');

      var changelogVersion = package.changelog.latestVersion;
      print('changelog:');
      print(package.changelog.describeLatestChanges.trimRight());

      if (pubspecVersion != changelogVersion) {
        var result = Result.fail(
          package,
          'pubspec version ($pubspecVersion) and changelog ($changelogVersion) '
          "don't agree",
        );
        print(result);
        results.addResult(result);
        continue;
      }

      if (await pub.hasPublishedVersion(package.name, pubspecVersion)) {
        var result = Result.info(package, 'already published at pub.dev');
        print(result);
        results.addResult(result);
      } else if (package.pubspec.isPreRelease) {
        var result = Result.info(
          package,
          'version $pubspecVersion is pre-release; no publish is necessary',
        );
        print(result);
        results.addResult(result);
      } else {
        var code = await runCommand('dart',
            args: ['pub', 'publish', '--dry-run'], cwd: package.directory);
        if (code != 0) {
          exitCode = code;
          results.addResult(Result.fail(package, 'pub publish dry-run failed'));
        } else {
          print('No issues found.');

          var result = Result.success(package,
              '**ready to publish**; merge and tag to publish', repoTag);
          print(result);
          results.addResult(result);
        }
      }
    }

    pub.close();

    return results;
  }

  /// Publish the indicated package in the repository.
  ///
  /// This is intended to be run on a github workflow in response to a git tag.
  /// It will:
  /// - validate the tag
  /// - validate the package exists
  /// - validate changelog and pubspec versions
  /// - perform a publish
  Future publish() async {
    var success = await _publish();
    if (!success && exitCode == 0) {
      exitCode = 1;
    }
  }

  Future<bool> _publish() async {
    var github = Github();

    if (!_expectEnv(github.refName, 'GITHUB_REF_NAME')) return false;

    // Validate the git tag.
    var tag = Tag(github.refName!);
    if (!tag.valid) {
      stderr.writeln("Git tag not in expected format: '$tag'");
      return false;
    }

    print("Publishing '$tag'");
    print('');

    var repo = Repository();
    var packages = repo.locatePackages();
    print('');
    print('Repository packages:');
    for (var package in packages) {
      print('  $package');
    }
    print('');

    // Find package to publish.
    Package package;
    if (repo.isSinglePackageRepo) {
      if (packages.isEmpty) {
        stderr.writeln('No publishable package found.');
        return false;
      }
      package = packages.first;
    } else {
      var name = tag.package;
      if (name == null) {
        stderr.writeln("Tag does not include package name ('$tag').");
        return false;
      }
      if (!packages.any((p) => p.name == name)) {
        stderr.writeln("Tag does not match a repo package ('$tag').");
        return false;
      }
      package = packages.firstWhere((p) => p.name == name);
    }

    print('');
    print('Publishing ${'package:${package.name}'}');
    print('');

    print('pubspec:');
    var pubspecVersion = package.pubspec.version;
    print('  version: $pubspecVersion');

    print('changelog:');
    print(package.changelog.describeLatestChanges);
    var changelogVersion = package.changelog.latestVersion;

    if (pubspecVersion != tag.version) {
      stderr.writeln(
          "Pubspec version ($pubspecVersion) and git tag ($tag) don't agree.");
      return false;
    }

    if (pubspecVersion != changelogVersion) {
      stderr.writeln('Pubspec version ($pubspecVersion) and changelog version '
          "($changelogVersion) don't agree.");
      return false;
    }

    await runCommand('dart', args: ['pub', 'get'], cwd: package.directory);
    print('');

    var result = await runCommand('dart',
        args: ['pub', 'publish', '--force'], cwd: package.directory);
    if (result != 0) {
      exitCode = result;
    }
    return result == 0;
  }

  bool _expectEnv(String? value, String name) {
    if (value == null) {
      print("Expected environment variable not found: '$name'");
      return false;
    } else {
      return true;
    }
  }
}

class VerificationResults {
  final List<Result> results = [];

  void addResult(Result result) => results.add(result);

  bool get hasSuccess => results.any((r) => r.severity == Severity.success);

  bool get hasError => results.any((r) => r.severity == Severity.error);

  String get describeAsMarkdown {
    results.sort((a, b) => Enum.compareByIndex(a.severity, b.severity));

    return results.map((r) {
      var sev = r.severity == Severity.error ? '(error) ' : '';
      var tag = r.other == null ? '' : '`${r.other}`';

      return '| package:${r.package.name} | ${r.package.version} | '
          '$sev${r.message} | $tag |';
    }).join('\n');
  }
}

class Result {
  final Severity severity;
  final Package package;
  final String message;
  final String? other;

  Result(this.severity, this.package, this.message, [this.other]);

  factory Result.fail(Package package, String message) =>
      Result(Severity.error, package, message);

  factory Result.info(Package package, String message) =>
      Result(Severity.info, package, message);

  factory Result.success(Package package, String message, [String? other]) =>
      Result(Severity.success, package, message, other);

  @override
  String toString() {
    final details = other == null ? '' : ' ($other)';
    return severity == Severity.error
        ? 'error: $message$details'
        : '$message$details';
  }
}

enum Severity {
  success,
  info,
  error;
}