'use strict';

const DEFAULT_GRACE_MS = 15000;

const CLEAN_SHUTDOWN = /\[(?:Render thread|Client thread)\/INFO\](?:\s+\([^)]*\))?:\s*Stopping!\s*$/;
const FATAL_OUTPUT = [
  /---- Minecraft Crash Report ----/i,
  /\b(?:Encountered an unexpected exception|Unreported exception thrown|Reported exception thrown)\b/i,
  /\b(?:This crash report has been saved to|Saving crash report to)\b/i,
  /\bA fatal error has been detected by the Java Runtime Environment\b/i,
  /Exception in thread "(?:Render thread|Client thread|main)"/i,
  /\[(?:Render thread|Client thread|main)\/FATAL\]/i,
];

function createProcessWatchdog(options) {
  const graceMs = options.graceMs || DEFAULT_GRACE_MS;
  const schedule = options.setTimer || setTimeout;
  const cancel = options.clearTimer || clearTimeout;
  const buffers = { stdout: '', stderr: '' };
  let timer = null;
  let armed = false;
  let crashed = false;
  let ended = false;
  let forced = false;
  // bleibt true, sobald einmal ein regulärer Shutdown ("Stopping!") gesehen
  // wurde – im Gegensatz zu `armed` wird das NICHT durch markCrash()
  // zurückgesetzt, damit ein später vom internen Watchdog erzwungener Halt
  // weiterhin als "war ein regulärer Shutdown" erkennbar bleibt
  let sawCleanShutdown = false;

  function clear() {
    if (timer !== null) cancel(timer);
    timer = null;
    armed = false;
  }

  function markCrash() {
    crashed = true;
    clear();
  }

  function scheduleKill() {
    if (timer !== null) cancel(timer);
    timer = schedule(() => {
      timer = null;
      if (ended || crashed || !armed || !options.isRunning()) return;
      try {
        forced = options.kill() === true;
      } catch {
        forced = false;
      }
      if (forced && options.onForce) options.onForce(graceMs);
      else if (!forced && options.isRunning() && options.onError) options.onError();
    }, graceMs);
    if (timer && typeof timer.unref === 'function') timer.unref();
  }

  function inspectLine(line) {
    const isCleanShutdown = CLEAN_SHUTDOWN.test(line);
    if (isCleanShutdown) sawCleanShutdown = true;
    if (FATAL_OUTPUT.some((pattern) => pattern.test(line))) {
      markCrash();
      return;
    }
    if (ended || crashed || armed || !isCleanShutdown) return;

    armed = true;
    scheduleKill();
  }

  function feed(chunk, stream) {
    if (ended) return;
    const key = stream === 'stderr' ? 'stderr' : 'stdout';
    const text = buffers[key] + String(chunk || '');
    const lines = text.split(/\r?\n/);
    buffers[key] = lines.pop() || '';
    for (const line of lines) inspectLine(line);
    if (armed && !crashed && !ended && lines.length) scheduleKill();
  }

  function end() {
    ended = true;
    clear();
  }

  return {
    feed,
    end,
    get armed() { return armed; },
    get crashed() { return crashed; },
    get forced() { return forced; },
    get sawCleanShutdown() { return sawCleanShutdown; },
  };
}

module.exports = {
  DEFAULT_GRACE_MS,
  CLEAN_SHUTDOWN,
  FATAL_OUTPUT,
  createProcessWatchdog,
};