'use strict';

const path = require('path');
const { spawn, fork } = require('node:child_process');
const CLI = require('./_cli.js');
const { styleText } = require('node:util');

const cli = new CLI(`usage: ./node run.js [options] [--] <category> ...
  Run each benchmark in the <category> directory a single time, more than one
  <category> directory can be specified.

  --filter   pattern        includes only benchmark scripts matching <pattern>
                            (can be repeated)
  --exclude  pattern        excludes scripts matching <pattern> (can be
                            repeated)
  --runs   variable=value   set the amount of benchmark suite execution.
                            Default: 1
  --set    variable=value   set benchmark variable (can be repeated)
  --format [simple|csv]     optional value that specifies the output format
  --track                   Display the time elapsed to run each benchmark file.
  test                      only run a single configuration from the options
                            matrix
  all                       each benchmark category is run one after the other

  Examples:
    --set CPUSET=0            Runs benchmarks on CPU core 0.
    --set CPUSET=0-2          Specifies that benchmarks should run on CPU cores 0 to 2.

  Note: The CPUSET format should match the specifications of the 'taskset' command on your system.
`, { arrayArgs: ['set', 'filter', 'exclude'], boolArgs: ['track'] });

const benchmarks = cli.benchmarks();

if (benchmarks.length === 0) {
  console.error('No benchmarks found');
  process.exitCode = 1;
  return;
}

const validFormats = ['csv', 'simple'];
const format = cli.optional.format || 'simple';
if (!validFormats.includes(format)) {
  console.error('Invalid format detected');
  process.exitCode = 1;
  return;
}

if (format === 'csv') {
  console.log('"filename", "configuration", "rate", "time"');
}

function runBenchmark(filename) {
  const scriptPath = path.resolve(__dirname, filename);

  const args = cli.test ? ['--test'] : cli.optional.set;
  const cpuCore = cli.getCpuCoreSetting();
  let child;
  if (cpuCore !== null) {
    child = spawn('taskset', ['-c', cpuCore, process.execPath, scriptPath, ...args], {
      stdio: ['inherit', 'inherit', 'inherit', 'ipc'],
    });
  } else {
    child = fork(
      scriptPath,
      args,
    );
  }

  return new Promise((resolve, reject) => {
    child.on('message', (data) => {
      if (data.type !== 'report') {
        return;
      }
      // Construct configuration string, " A=a, B=b, ..."
      let conf = '';
      for (const key of Object.keys(data.conf)) {
        if (conf !== '')
          conf += ' ';
        conf += `${key}=${JSON.stringify(data.conf[key])}`;
      }
      if (format === 'csv') {
        // Escape quotes (") for correct csv formatting
        conf = conf.replace(/"/g, '""');
        console.log(`"${data.name}", "${conf}", ${data.rate}, ${data.time}`);
      } else {
        let rate = data.rate.toString().split('.');
        rate[0] = rate[0].replace(/(\d)(?=(?:\d\d\d)+(?!\d))/g, '$1,');
        rate = (rate[1] ? rate.join('.') : rate[0]);
        console.log(`${data.name} ${conf}: ${rate}`);
      }
    });
    child.once('close', (code) => {
      if (code) {
        reject(code);
      } else {
        resolve(code);
      }
    });
  });
}

async function run() {
  for (let i = 0; i < benchmarks.length; ++i) {
    let runs = cli.optional.runs ?? 1;
    const filename = benchmarks[i];
    if (format !== 'csv') {
      console.log();
      console.log(filename);
    }

    while (runs-- > 0) {
      const start = performance.now();
      await runBenchmark(filename);
      if (format !== 'csv' && cli.optional.track) {
        const ms = styleText(['bold', 'yellow'], `${Math.round(performance.now() - start)}ms`);
        console.log(`[${ms}] ${filename}`);
      }
    }
  }
}

run();