#!/usr/bin/env dart
// Copyright (c) 2018, 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.

// Run tests like on the given builder.

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:args/args.dart';

import 'bots/results.dart';

const int deflakingCount = 5;

/// Returns the operating system of a builder.
String systemOfBuilder(String builder) {
  return builder.split("-").firstWhere(
      (component) => ["linux", "mac", "win"].contains(component),
      orElse: () => null);
}

/// Returns the product mode of a builder.
String modeOfBuilder(String builder) {
  return builder.split("-").firstWhere(
      (component) => ["debug", "product", "release"].contains(component),
      orElse: () => null);
}

/// Returns the machine architecture of a builder.
String archOfBuilder(String builder) {
  return builder.split("-").firstWhere(
      (component) => [
            "arm",
            "arm64",
            "armsimdbc",
            "armsimdbc64",
            "ia32",
            "simarm",
            "simarm64",
            "simdbc",
            "simdbc64",
            "x64",
          ].contains(component),
      orElse: () => null);
}

/// Returns the runtime environment of a builder.
String runtimeOfBuilder(String builder) {
  return builder.split("-").firstWhere(
      (component) => ["chrome", "d8", "edge", "firefox", "ie11", "safari"]
          .contains(component),
      orElse: () => null);
}

/// Expands a variable in a test matrix step command.
String expandVariable(String string, String variable, String value) {
  return string.replaceAll("\${$variable}", value ?? "");
}

/// Expands all variables in a test matrix step command.
String expandVariables(String string, String builder) {
  string = expandVariable(string, "system", systemOfBuilder(builder));
  string = expandVariable(string, "mode", modeOfBuilder(builder));
  string = expandVariable(string, "arch", archOfBuilder(builder));
  string = expandVariable(string, "runtime", runtimeOfBuilder(builder));
  return string;
}

/// Locates the merge base between head and the [branch] on the given [remote].
/// If a particular [commit] was requested, use that.
Future<String> findMergeBase(
    String commit, String remote, String branch) async {
  if (commit != null) {
    return commit;
  }
  final arguments = ["merge-base", "$remote/$branch", "HEAD"];
  final result = await Process.run("git", arguments);
  if (result.exitCode != 0) {
    throw new Exception("Failed to run: git ${arguments.join(' ')}\n"
        "stdout:\n${result.stdout}\n"
        "stderr:\n${result.stderr}\n");
  }
  return LineSplitter.split(result.stdout).first;
}

/// Locates the build number of the [commit] on the [builder], or throws an
/// exception if the builder hasn't built the commit.
Future<int> buildNumberOfCommit(String builder, String commit) async {
  final requestUrl = Uri.parse(
      "https://cr-buildbucket.appspot.com/_ah/api/buildbucket/v1/search"
      "?bucket=luci.dart.ci.sandbox"
      "&tag=builder%3A$builder"
      "&tag=buildset%3Acommit%2Fgit%2F$commit"
      "&fields=builds(status%2Ctags%2Curl)");
  final client = new HttpClient();
  final request = await client.getUrl(requestUrl);
  final response = await request.close();
  final Map<String, dynamic> object = await response
      .transform(new Utf8Decoder())
      .transform(new JsonDecoder())
      .first;
  client.close();
  final builds = object["builds"];
  if (builds.isEmpty) {
    throw new Exception("Builder $builder hasn't built commit $commit");
  }
  final build = builds.last;
  final tags = (build["tags"] as List).cast<String>();
  final buildAddressTag =
      tags.firstWhere((tag) => tag.startsWith("build_address:"));
  final buildAddress = buildAddressTag.substring("build_address:".length);
  if (build["status"] != "COMPLETED") {
    throw new Exception("Build $buildAddress isn't completed yet");
  }
  return int.parse(buildAddress.split("/").last);
}

void main(List<String> args) async {
  final parser = new ArgParser();
  parser.addOption("builder",
      abbr: "b", help: "Run tests like on the given buider");
  parser.addOption("branch",
      abbr: "B",
      help: "Select the builders building this branch",
      defaultsTo: "master");
  parser.addOption("commit", abbr: "C", help: "Compare with this commit");
  parser.addOption("remote",
      abbr: "R",
      help: "Compare with this remote and git branch",
      defaultsTo: "origin");
  parser.addFlag("help", help: "Show the program usage.", negatable: false);

  final options = parser.parse(args);
  if (options["help"] || options["builder"] == null) {
    print("""
Usage: test.dart -b [BUILDER] [OPTION]...
Run tests and compare with the results on the given builder.

${parser.usage}""");
    return;
  }

  final builder = options["builder"];

  // Find out where the current HEAD branched.
  final commit = await findMergeBase(
      options["commit"], options["remote"], options["branch"]);
  print("Base commit is $commit");

  // Use the buildbucket API to search for builds of the right rcommit.
  print("Finding build to compare with...");
  final buildNumber = await buildNumberOfCommit(builder, commit);
  print("Comparing with build $buildNumber on $builder");

  final outDirectory = await Directory.systemTemp.createTemp("test.dart.");
  try {
    // Download the previous results and flakiness info from cloud storage.
    print("Downloading previous results...");
    await cpGsutil(
        buildFileCloudPath(builder, buildNumber.toString(), "results.json"),
        "${outDirectory.path}/previous.json");
    await cpGsutil(
        buildFileCloudPath(builder, buildNumber.toString(), "flaky.json"),
        "${outDirectory.path}/flaky.json");
    print("Downloaded previous results");

    // Load the test matrix.
    final scriptPath = Platform.script.toFilePath();
    final testMatrixPath =
        scriptPath.substring(0, scriptPath.length - "test.dart".length) +
            "bots/test_matrix.json";
    final testMatrix =
        jsonDecode(await new File(testMatrixPath).readAsString());

    // Find the appropriate test.py steps.
    final buildersConfigurations = testMatrix["builder_configurations"];
    final builderConfiguration = buildersConfigurations.firstWhere(
        (builderConfiguration) =>
            (builderConfiguration["builders"] as List).contains(builder));
    final steps = (builderConfiguration["steps"] as List).cast<Map>();
    final testSteps = steps
        .where((step) =>
            !step.containsKey("script") || step["script"] == "tools/test.py")
        .toList();

    // Run each step like the builder would, deflaking tests that need it.
    final stepResultsPaths = <String>[];
    for (int stepIndex = 0; stepIndex < testSteps.length; stepIndex++) {
      // Run the test step.
      final testStep = testSteps[stepIndex];
      final stepName = testStep["name"];
      final stepDirectory = new Directory("${outDirectory.path}/$stepIndex");
      await stepDirectory.create();
      final stepArguments = testStep["arguments"]
          .map((argument) => expandVariables(argument, builder))
          .toList()
          .cast<String>();
      final fullArguments = <String>[]
        ..addAll(stepArguments)
        ..addAll(
            ["--output-directory=${stepDirectory.path}", "--write-results"])
        ..addAll(options.rest);
      print("$stepName: Running tests");
      final testProcess = await Process.start("tools/test.py", fullArguments);
      await testProcess.exitCode;
      stepResultsPaths.add("${stepDirectory.path}/results.json");
      // Find the list of tests to deflake.
      final deflakeListOutput = await Process.run(Platform.resolvedExecutable, [
        "tools/bots/compare_results.dart",
        "--changed",
        "--failing",
        "--passing",
        "--flakiness-data=${outDirectory.path}/flaky.json",
        "${outDirectory.path}/previous.json",
        "${stepDirectory.path}/results.json"
      ]);
      final deflakeListPath = "${stepDirectory.path}/deflake.list";
      final deflakeListFile = new File(deflakeListPath);
      await deflakeListFile.writeAsString(deflakeListOutput.stdout);
      // Deflake the changed tests.
      final deflakingResultsPaths = <String>[];
      for (int i = 1;
          deflakeListOutput.stdout != "" && i <= deflakingCount;
          i++) {
        print("$stepName: Running deflaking iteration $i");
        final deflakeDirectory = new Directory("${stepDirectory.path}/$i");
        await deflakeDirectory.create();
        final deflakeArguments = <String>[]
          ..addAll(stepArguments)
          ..addAll([
            "--output-directory=${deflakeDirectory.path}",
            "--write-results",
            "--write-logs",
            "--test-list=$deflakeListPath"
          ])
          ..addAll(options.rest);
        final deflakeProcess =
            await Process.start("tools/test.py", deflakeArguments);
        await deflakeProcess.exitCode;
        deflakingResultsPaths.add("${deflakeDirectory.path}/results.json");
      }
      // Update the flakiness information based on what we've learned.
      print("$stepName: Updating flakiness information");
      await Process.run(
          "tools/bots/update_flakiness.dart",
          [
            "--input=${outDirectory.path}/flaky.json",
            "--output=${outDirectory.path}/flaky.json",
            "${stepDirectory.path}/results.json",
          ]..addAll(deflakingResultsPaths));
    }
    // Collect all the results from all the steps.
    await new File("${outDirectory.path}/results.json").writeAsString(
        stepResultsPaths
            .map((path) => new File(path).readAsStringSync())
            .join(""));
    // Write out the final comparison.
    print("");
    final compareOutput = await Process.run("tools/bots/compare_results.dart", [
      "--human",
      "--verbose",
      "--changed",
      "--failing",
      "--passing",
      "--flakiness-data=${outDirectory.path}/flaky.json",
      "--logs=${outDirectory.path}/logs.json",
      "${outDirectory.path}/previous.json",
      "${outDirectory.path}/results.json"
    ]);
    stdout.write(compareOutput.stdout);
  } finally {
    await outDirectory.delete(recursive: true);
  }
}