// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Rolls the dev channel.
// Only tested on Linux.
//
// See: https://github.com/flutter/flutter/wiki/Release-process

import 'dart:io';

import 'package:args/args.dart';

const String kIncrement = 'increment';
const String kX = 'x';
const String kY = 'y';
const String kZ = 'z';
const String kCommit = 'commit';
const String kOrigin = 'origin';
const String kJustPrint = 'just-print';
const String kYes = 'yes';
const String kHelp = 'help';

const String kUpstreamRemote = 'git@github.com:flutter/flutter.git';

void main(List<String> args) {
  final ArgParser argParser = ArgParser(allowTrailingOptions: false);

  argParser.addOption(
    kIncrement,
    help: 'Specifies which part of the x.y.z version number to increment. Required.',
    valueHelp: 'level',
    allowed: <String>[kX, kY, kZ],
    allowedHelp: <String, String>{
      kX: 'Indicates a major development, e.g. typically changed after a big press event.',
      kY: 'Indicates a minor development, e.g. typically changed after a beta release.',
      kZ: 'Indicates the least notable level of change. You normally want this.',
    },
  );
  argParser.addOption(
    kCommit,
    help: 'Specifies which git commit to roll to the dev branch. Required.',
    valueHelp: 'hash',
    defaultsTo: null, // This option is required
  );
  argParser.addOption(
    kOrigin,
    help: 'Specifies the name of the upstream repository',
    valueHelp: 'repository',
    defaultsTo: 'upstream',
  );
  argParser.addFlag(
    kJustPrint,
    negatable: false,
    help:
        "Don't actually roll the dev channel; "
        'just print the would-be version and quit.',
  );
  argParser.addFlag(kYes, negatable: false, abbr: 'y', help: 'Skip the confirmation prompt.');
  argParser.addFlag(kHelp, negatable: false, help: 'Show this help message.', hide: true);

  ArgResults argResults;
  try {
    argResults = argParser.parse(args);
  } on ArgParserException catch (error) {
    print(error.message);
    print(argParser.usage);
    exit(1);
  }

  final String level = argResults[kIncrement] as String;
  final String commit = argResults[kCommit] as String;
  final String origin = argResults[kOrigin] as String;
  final bool justPrint = argResults[kJustPrint] as bool;
  final bool autoApprove = argResults[kYes] as bool;
  final bool help = argResults[kHelp] as bool;

  if (help || level == null || commit == null) {
    print('roll_dev.dart --increment=level --commit=hash • update the version tags and roll a new dev build.\n');
    print(argParser.usage);
    exit(0);
  }

  if (getGitOutput('remote get-url $origin', 'check whether this is a flutter checkout') != kUpstreamRemote) {
    print('The current directory is not a Flutter repository checkout with a correctly configured upstream remote.');
    print('For more details see: https://github.com/flutter/flutter/wiki/Release-process');
    exit(1);
  }

  if (getGitOutput('status --porcelain', 'check status of your local checkout') != '') {
    print('Your git repository is not clean. Try running "git clean -fd". Warning, this ');
    print('will delete files! Run with -n to find out which ones.');
    exit(1);
  }

  runGit('fetch $origin', 'fetch $origin');
  runGit('reset $commit --hard', 'reset to the release commit');

  String version = getFullTag();
  final Match match = parseFullTag(version);
  if (match == null) {
    print('Could not determine the version for this build.');
    if (version.isNotEmpty)
      print('Git reported the latest version as "$version", which does not fit the expected pattern.');
    exit(1);
  }

  final List<int> parts = match.groups(<int>[1, 2, 3, 4, 5]).map<int>(int.parse).toList();

  if (match.group(6) == '0') {
    print('This commit has already been released, as version ${getVersionFromParts(parts)}.');
    exit(0);
  }

  switch (level) {
    case kX:
      parts[0] += 1;
      parts[1] = 0;
      parts[2] = 0;
      parts[3] = 0;
      parts[4] = 0;
      break;
    case kY:
      parts[1] += 1;
      parts[2] = 0;
      parts[3] = 0;
      parts[4] = 0;
      break;
    case kZ:
      parts[2] = 0;
      parts[3] += 1;
      parts[4] = 0;
      break;
    default:
      print('Unknown increment level. The valid values are "$kX", "$kY", and "$kZ".');
      exit(1);
  }
  version = getVersionFromParts(parts);

  if (justPrint) {
    print(version);
    exit(0);
  }

  final String hash = getGitOutput('rev-parse HEAD', 'Get git hash for $commit');

  runGit('tag $version', 'tag the commit with the version label');

  // PROMPT

  if (autoApprove) {
    print('Publishing Flutter $version (${hash.substring(0, 10)}) to the "dev" channel.');
  } else {
    print('Your tree is ready to publish Flutter $version (${hash.substring(0, 10)}) '
      'to the "dev" channel.');
    stdout.write('Are you? [yes/no] ');
    if (stdin.readLineSync() != 'yes') {
      runGit('tag -d $version', 'remove the tag you did not want to publish');
      print('The dev roll has been aborted.');
      exit(0);
    }
  }

  runGit('push $origin $version', 'publish the version');
  runGit('push $origin HEAD:dev', 'land the new version on the "dev" branch');
  print('Flutter version $version has been rolled to the "dev" channel!');
}

String getFullTag() {
  const String glob = '*.*.*-*.*.pre';
  return getGitOutput(
    'describe --match $glob --first-parent --long --tags',
    'obtain last released version number',
  );
}

Match parseFullTag(String version) {
  // of the form: x.y.z-m.n.pre-c-g<revision>
  final RegExp versionPattern = RegExp(
    r'^(\d+)\.(\d+)\.(\d+)-(\d+)\.(\d+)\.pre-(\d+)-g([a-f0-9]+)$');
  return versionPattern.matchAsPrefix(version);
}

String getVersionFromParts(List<int> parts) {
  // where parts correspond to [x, y, z, m, n] from tag
  assert(parts.length == 5);
  final StringBuffer buf = StringBuffer()
    // take x, y, and z
    ..write(parts.take(3).join('.'))
    ..write('-')
    // skip x, y, and z, take m and n
    ..write(parts.skip(3).take(2).join('.'))
    ..write('.pre');
  // return a string that looks like: '1.2.3-4.5.pre'
  return buf.toString();
}

String getGitOutput(String command, String explanation) {
  final ProcessResult result = _runGit(command);
  if ((result.stderr as String).isEmpty && result.exitCode == 0)
    return (result.stdout as String).trim();
  _reportGitFailureAndExit(result, explanation);
  return null; // for the analyzer's sake
}

void runGit(String command, String explanation) {
  final ProcessResult result = _runGit(command);
  if (result.exitCode != 0)
    _reportGitFailureAndExit(result, explanation);
}

ProcessResult _runGit(String command) {
  return Process.runSync('git', command.split(' '));
}

void _reportGitFailureAndExit(ProcessResult result, String explanation) {
  if (result.exitCode != 0) {
    print('Failed to $explanation. Git exited with error code ${result.exitCode}.');
  } else {
    print('Failed to $explanation.');
  }
  if ((result.stdout as String).isNotEmpty)
    print('stdout from git:\n${result.stdout}\n');
  if ((result.stderr as String).isNotEmpty)
    print('stderr from git:\n${result.stderr}\n');
  exit(1);
}