import { execFileSync } from 'child_process';

const CPU_THRESHOLD_SECONDS = 3600; // 1 hour

export function parsePowerShellOutput(csv, now = new Date()) {
  const lines = csv.trim().split(/\r?\n/);
  if (lines.length < 2) return [];
  const header = lines[0].split(',');
  const idxPid = header.indexOf('Id');
  const idxName = header.indexOf('ProcessName');
  const idxCpu = header.indexOf('CPU');
  const idxStart = header.indexOf('StartTime');
  const procs = [];
  for (let i = 1; i < lines.length; i++) {
    const cells = lines[i].split(',');
    if (cells.length < 4) continue;
    const startTime = new Date(cells[idxStart]);
    const ageMinutes = Math.max(0, Math.floor((now - startTime) / 60000));
    procs.push({
      pid: parseInt(cells[idxPid], 10),
      name: cells[idxName],
      cpuSeconds: parseFloat(cells[idxCpu]),
      ageMinutes,
    });
  }
  return procs;
}

export function queryRunningProcesses() {
  // PowerShell command: get heavy processes, output as CSV without quotes
  const psCmd = "Get-Process | Where-Object {$_.CPU -gt 3600} | Select-Object Id,ProcessName,CPU,StartTime | ConvertTo-Csv -NoTypeInformation | ForEach-Object {$_ -replace '\"',''}";
  try {
    const out = execFileSync('powershell.exe', [
      '-NoProfile', '-NonInteractive',
      '-Command',
      psCmd,
    ], { encoding: 'utf-8', timeout: 5000 });
    return parsePowerShellOutput(out, new Date());
  } catch (e) {
    return [];
  }
}

export function computeSystemHealthBlock(procs) {
  const heavy = (procs || [])
    .filter(p => p.cpuSeconds > CPU_THRESHOLD_SECONDS)
    .sort((a, b) => b.cpuSeconds - a.cpuSeconds)
    .slice(0, 3);
  if (heavy.length === 0) {
    return `## System Health\n\nДолго работающих процессов нет (порог CPU > 1ч).\n`;
  }
  const rows = heavy.map(p => {
    const hours = (p.cpuSeconds / 3600).toFixed(2);
    const ageHours = (p.ageMinutes / 60).toFixed(1);
    return `| ${p.pid} | ${p.name} | ${hours}ч | ${ageHours}ч |`;
  }).join('\n');
  return `## System Health\n\nТоп-3 процессов с CPU > 1ч:\n\n| PID | Имя | CPU-время | Возраст |\n|---|---|---|---|\n${rows}\n\n⚠️ Проверь, не «осиротевшие» ли это процессы от завершённых Claude-сессий.\n`;
}