/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */

import {setOutput} from '@actions/core';
import {GitClient, Log, bold, green, yellow} from '@angular/ng-dev';
import {select} from '@inquirer/prompts';
import yargs from 'yargs';
import {collectBenchmarkResults} from './results.mts';
import {
  type ResolvedTarget,
  findBenchmarkTargets,
  getTestlogPath,
  resolveTarget,
} from './targets.mts';
import {exec} from './utils.mts';

const benchmarkTestFlags = [
  '--cache_test_results=no',
  '--color=yes',
  '--curses=no',
  // We may have RBE set up, but test should run locally on the same machine to
  // reduce fluctuation. Output streamed ensures that deps can build with RBE, but
  // tests run locally while also providing useful output for debugging.
  '--test_output=streamed',
];

await yargs(process.argv.slice(2))
  .command(
    'run-compare <compare-ref> [bazel-target]',
    'Runs a benchmark between two SHAs',
    (argv) =>
      argv
        .positional('compare-ref', {
          description: 'Comparison SHA',
          type: 'string',
          demandOption: true,
        })
        .positional('bazel-target', {description: 'Bazel target', type: 'string'}),
    (args) => runCompare(args.bazelTarget, args.compareRef),
  )
  .command(
    'run [bazel-target]',
    'Runs a benchmark',
    (argv) => argv.positional('bazel-target', {description: 'Bazel target', type: 'string'}),
    (args) => runBenchmarkCmd(args.bazelTarget),
  )
  .command(
    'prepare-for-github-action <comment-body>',
    false, // Do not show in help.
    (argv) => argv.positional('comment-body', {demandOption: true, type: 'string'}),
    (args) => prepareForGitHubAction(args.commentBody),
  )
  .demandCommand()
  .scriptName('$0')
  .help()
  .strict()
  .parseAsync();

/** Prompts for a benchmark target. */
async function promptForBenchmarkTarget(): Promise<string> {
  const targets = await findBenchmarkTargets();

  return await select({
    message: 'Select benchmark target to run:',
    choices: targets.map((t) => ({value: t, name: t})),
  });
}

/**
 * Prepares a benchmark comparison running via GitHub action. This command is
 * used by the GitHub action YML workflow and is responsible for extracting
 * e.g. command information or fetching/resolving Git refs of the comparison range.
 *
 * This is a helper used by the GitHub action to perform benchmark
 * comparisons. Commands follow the format of: `/benchmark-compare <sha> <target>`.
 */
async function prepareForGitHubAction(commentBody: string): Promise<void> {
  const matches = /\/[^ ]+ ([^ ]+) ([^ ]+)/.exec(commentBody);
  if (matches === null) {
    Log.error('Could not extract information from comment', commentBody);
    process.exit(1);
  }

  const git = await GitClient.get();
  const [_, compareRefRaw, benchmarkTarget] = matches;

  // We assume the PR is checked out and therefore `HEAD` is the PR head SHA.
  const prHeadSha = git.run(['rev-parse', 'HEAD']).stdout.trim();

  setOutput('benchmarkTarget', benchmarkTarget);
  setOutput('prHeadSha', prHeadSha);

  // Attempt to find the compare SHA. The commit may be either part of the
  // pull request, or might be a commit unrelated to the PR- but part of the
  // upstream repository. We attempt to fetch/resolve the SHA in both remotes.
  const compareRefResolve = git.runGraceful(['rev-parse', compareRefRaw]);
  let compareRefSha = compareRefResolve.stdout.trim();
  if (compareRefSha === '' || compareRefResolve.status !== 0) {
    git.run(['fetch', '--depth=1', git.getRepoGitUrl(), compareRefRaw]);
    compareRefSha = git.run(['rev-parse', 'FETCH_HEAD']).stdout.trim();
  }

  setOutput('compareSha', compareRefSha);
}

/** Runs a specified benchmark, or a benchmark selected via prompt. */
async function runBenchmarkCmd(bazelTargetRaw: string | undefined): Promise<void> {
  if (bazelTargetRaw === undefined) {
    bazelTargetRaw = await promptForBenchmarkTarget();
  }
  const bazelTarget = await resolveTarget(bazelTargetRaw);
  const testlogPath = await getTestlogPath(bazelTarget);

  await runBenchmarkTarget(bazelTarget);

  const workingDirResults = await collectBenchmarkResults(testlogPath);

  Log.info('\n\n\n');
  Log.info(bold(green('Results!')));
  Log.info(workingDirResults.summaryConsoleText);
}

/** Runs a benchmark Bazel target. */
async function runBenchmarkTarget(bazelTarget: ResolvedTarget): Promise<void> {
  await exec('bazel', ['test', bazelTarget, ...benchmarkTestFlags]);
}

/**
 * Performs a comparison of benchmark results between the current
 * working stage and the comparison Git reference.
 */
async function runCompare(bazelTargetRaw: string | undefined, compareRef: string): Promise<void> {
  const git = await GitClient.get();
  const currentRef = git.getCurrentBranchOrRevision();

  if (git.hasUncommittedChanges()) {
    Log.warn(bold('You have uncommitted changes.'));
    Log.warn('The script will stash your changes and re-apply them so that');
    Log.warn('the comparison ref can be checked out.');
    Log.warn('');
  }

  if (bazelTargetRaw === undefined) {
    bazelTargetRaw = await promptForBenchmarkTarget();
  }

  const bazelTarget = await resolveTarget(bazelTargetRaw);
  const testlogPath = await getTestlogPath(bazelTarget);

  Log.log(green(`Test log path: ${testlogPath}`));

  // Run benchmark with the current working stage.
  await runBenchmarkTarget(bazelTarget);

  const workingDirResults = await collectBenchmarkResults(testlogPath);

  // Stash working directory as we might be in the middle of developing
  // and we wouldn't want to discard changes when checking out the compare SHA.
  git.run(['stash']);

  try {
    Log.log(green('Fetching comparison revision.'));
    // Note: Not using a shallow fetch here as that would convert the local
    // user repository into an incomplete repository.
    git.run(['fetch', git.getRepoGitUrl(), compareRef]);
    Log.log(green('Checking out comparison revision.'));
    git.run(['checkout', 'FETCH_HEAD']);

    await exec('yarn');
    await runBenchmarkTarget(bazelTarget);
  } finally {
    restoreWorkingStage(git, currentRef);
  }

  // Re-install dependencies for `HEAD`.
  await exec('yarn');

  const comparisonResults = await collectBenchmarkResults(testlogPath);

  // If we are running in a GitHub action, expose the benchmark text
  // results as outputs. Useful if those are exposed as a GitHub comment then.
  if (process.env.GITHUB_ACTION !== undefined) {
    setOutput('comparisonResultsText', comparisonResults.summaryMarkdownText);
    setOutput('workingStageResultsText', workingDirResults.summaryMarkdownText);
  }

  Log.info('\n\n\n');
  Log.info(bold(green('Results!')));

  Log.info(bold(yellow(`Comparison reference (${compareRef}) results:`)), '\n');
  Log.info(comparisonResults.summaryConsoleText);

  Log.info(bold(yellow(`Working stage (${currentRef}) results:`)), '\n');
  Log.info(workingDirResults.summaryConsoleText);
}

function restoreWorkingStage(git: GitClient, initialRef: string) {
  Log.log(green('Restoring working stage'));
  git.run(['checkout', '-f', initialRef]);

  // Stash apply could fail if there were not changes in the working stage.
  git.runGraceful(['stash', 'apply']);
}