#!/usr/bin/env node
/**
 * Background Process Tracker - Enforces inst_023
 */

const fs = require('fs');
const path = require('path');

const SESSION_STATE = path.join(__dirname, '../.claude/session-state.json');

function loadState() {
  if (!fs.existsSync(SESSION_STATE)) return { background_processes: [] };
  return JSON.parse(fs.readFileSync(SESSION_STATE, 'utf8'));
}

function saveState(state) {
  fs.writeFileSync(SESSION_STATE, JSON.stringify(state, null, 2));
}

function isRunning(pid) {
  try {
    process.kill(pid, 0);
    return true;
  } catch (e) {
    return false;
  }
}

function register(pid, description, persistent = false) {
  const state = loadState();
  if (!state.background_processes) state.background_processes = [];

  state.background_processes.push({
    pid: parseInt(pid),
    description,
    persistent,
    started_at: new Date().toISOString(),
    session: state.session_id
  });

  saveState(state);
  console.log(`✅ Registered: PID ${pid} - ${description}${persistent ? ' [PERSISTENT]' : ''}`);
}

function list() {
  const state = loadState();
  const procs = state.background_processes || [];

  if (procs.length === 0) {
    console.log('No tracked processes');
    return;
  }

  console.log('\n📋 Background Processes:\n');
  procs.forEach(p => {
    const status = isRunning(p.pid) ? '✓' : '✗';
    console.log(`${status} PID ${p.pid}: ${p.description} ${p.persistent ? '[PERSISTENT]' : ''}`);
  });
  console.log('');
}

function cleanup(force = false) {
  const state = loadState();
  const procs = state.background_processes || [];
  let killed = 0;
  const remaining = [];

  procs.forEach(p => {
    if (!isRunning(p.pid)) return;
    if (p.persistent && !force) {
      remaining.push(p);
      return;
    }
    try {
      process.kill(p.pid, 'SIGTERM');
      console.log(`✓ Killed PID ${p.pid}`);
      killed++;
    } catch (err) {
      remaining.push(p);
    }
  });

  state.background_processes = remaining;
  saveState(state);
  console.log(`\n✅ Cleanup: ${killed} killed, ${remaining.length} remaining\n`);
}

const cmd = process.argv[2];
if (cmd === 'register') {
  register(process.argv[3], process.argv[4], process.argv.includes('--persistent'));
} else if (cmd === 'list') {
  list();
} else if (cmd === 'cleanup') {
  cleanup(process.argv.includes('--force'));
} else {
  console.log('Usage: register <pid> <desc> [--persistent] | list | cleanup [--force]');
}