// Copyright (c) 2021, 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 'package:baseline/options.dart';
import 'dart:convert';
import 'dart:io';

import 'package:pool/pool.dart';

const _resultBase = 'gs://dart-test-results';

/// Baselines a builder with the [options] and copies the results to the
/// [resultBase]. [resultBase] can be a URL or a path supported by `gsutil cp`.
Future<void> baseline(BaselineOptions options,
    [String resultBase = _resultBase]) async {
  await Future.wait([
    for (final channel in options.channels)
      if (channel == 'main')
        // baseline a new builder on main
        // builder,builder2 -> new-builder
        baselineBuilder(
            options.builders,
            channel,
            options.suites,
            options.target,
            options.configs,
            options.dryRun,
            options.mapping,
            resultBase)
      else if (options.builders.contains(options.target))
        // baseline a builder on a channel with main builder data
        // builder,builder2 -> builder-dev
        baselineBuilder(
            options.builders,
            channel,
            options.suites,
            '${options.target}-$channel',
            options.configs,
            options.dryRun,
            options.mapping,
            resultBase)
      else
        // baseline a builder on a channel with channel builder data
        // builder-dev,builder2-dev -> new-builder-dev
        baselineBuilder(
            options.builders.map((b) => '$b-$channel').toList(),
            channel,
            options.suites,
            '${options.target}-$channel',
            options.configs,
            options.dryRun,
            options.mapping,
            resultBase)
  ]);
}

Future<void> baselineBuilder(
    List<String> builders,
    String channel,
    Set<String> suites,
    String target,
    Map<String, List<String>> configs,
    bool dryRun,
    ConfigurationMapping mapping,
    String resultBase) async {
  var resultsStream = Pool(4).forEach(builders, (builder) async {
    var latest = await read('$resultBase/builders/$builder/latest');
    return await read('$resultBase/builders/$builder/$latest/results.json');
  });
  var modifiedResults = StringBuffer();
  var modifiedResultsPerConfig = <String, StringBuffer>{};
  await for (var results in resultsStream) {
    for (var json in LineSplitter.split(results)
        .map(jsonDecode)
        .cast<Map<String, dynamic>>()) {
      var configurations = mapping(json['configuration'], configs);
      if (configurations == null) {
        continue;
      }
      for (var configuration in configurations) {
        if (suites.isNotEmpty && !suites.contains(json['suite'])) continue;
        json['configuration'] = configuration;
        json['build_number'] = '0';
        json['previous_build_number'] = '0';
        json['builder_name'] = target;
        json['flaky'] = false;
        json['previous_flaky'] = false;

        var encoded = jsonEncode(json);
        modifiedResults.writeln(encoded);
        modifiedResultsPerConfig
            .putIfAbsent(configuration, () => StringBuffer())
            .writeln(encoded);
      }
      if (dryRun) break;
    }
  }
  await write('$resultBase/builders/$target/0/results.json',
      modifiedResults.toString(), dryRun);
  for (var entry in modifiedResultsPerConfig.entries) {
    await write(
        '$resultBase/configuration/$channel/${entry.key}/0/results.json',
        entry.value.toString(),
        dryRun);
  }
  await write('$resultBase/builders/$target/latest', '0', dryRun);
}

Future<String> read(String url) {
  return run('gsutil.py', ['cp', url, '-']);
}

Future<String> write(String url, String stdin, bool dryRun) {
  return run('gsutil.py', ['cp', '-', url], stdin: stdin, dryRun: dryRun);
}

Future<String> run(String command, List<String> arguments,
    {String? stdin, bool dryRun = false}) async {
  print('Running $command $arguments...');
  if (dryRun) {
    if (stdin != null) {
      print('stdin:\n$stdin');
    }
    return '';
  }
  var process = await Process.start(command, arguments);
  process.stderr.transform(utf8.decoder).forEach(print);
  if (stdin != null) {
    process.stdin.write(stdin);
    await process.stdin.flush();
    process.stdin.close();
  }
  var stdout = process.stdout.transform(utf8.decoder).join();
  var result = await process.exitCode;
  if (result != 0) {
    throw Exception('Failed to run $command $arguments: $result');
  }
  return await stdout;
}