/**
 * CtxHealth — Infrastructure Self-Healing Daemon
 *
 * Monitors infrastructure every 60 seconds:
 *   - PM2 processes, PostgreSQL, Ollama, Cloudflare tunnel,
 *     disk space, memory, network, WireGuard
 *
 * When a check fails:
 *   1. Calls LLM Gateway for AI-powered root cause analysis
 *   2. Executes auto-healing actions (with cooldown + escalation guards)
 *   3. Logs all incidents to PostgreSQL
 *
 * Safety rules:
 *   - After 3+ consecutive failures: escalate to human, skip healing
 *   - Cooldown: no re-healing same check within 5 minutes
 *   - Dry-run mode: CTX_HEALTH_DRY_RUN=true → diagnose but don't heal
 */

import cron from 'node-cron';
import { logger } from './observability/logger.js';
import { closePool } from './db/client.js';
import { runMigrations } from './db/incidents.js';
import { runHealthCycle } from './runner.js';

const DRY_RUN = process.env['CTX_HEALTH_DRY_RUN'] === 'true';
const CRON_SCHEDULE = process.env['CTX_HEALTH_CRON'] ?? '*/1 * * * *';

// ─── Startup ─────────────────────────────────────────────────────────────────

async function startup(): Promise<void> {
  logger.info({ dryRun: DRY_RUN, schedule: CRON_SCHEDULE }, 'CtxHealth daemon starting');

  try {
    await runMigrations();
  } catch (err) {
    logger.error({ err }, 'Migration failed — proceeding without DB (degraded mode)');
  }

  // Run one immediate cycle on start
  await safeRun();

  cron.schedule(CRON_SCHEDULE, () => {
    void safeRun();
  });

  logger.info('CtxHealth daemon running — press Ctrl+C to stop');
}

let cycleRunning = false;

async function safeRun(): Promise<void> {
  if (cycleRunning) {
    logger.warn('Previous health cycle still running — skipping this tick');
    return;
  }
  cycleRunning = true;
  const start = Date.now();
  try {
    await runHealthCycle(DRY_RUN);
    logger.debug({ durationMs: Date.now() - start }, 'Health cycle completed');
  } catch (err) {
    logger.error({ err, durationMs: Date.now() - start }, 'Health cycle crashed unexpectedly');
  } finally {
    cycleRunning = false;
  }
}

// ─── Graceful shutdown ───────────────────────────────────────────────────────

async function shutdown(signal: string): Promise<void> {
  logger.info({ signal }, 'CtxHealth shutting down gracefully');
  try {
    await closePool();
  } catch (err) {
    logger.warn({ err }, 'Error closing DB pool during shutdown');
  }
  process.exit(0);
}

process.on('SIGTERM', () => void shutdown('SIGTERM'));
process.on('SIGINT', () => void shutdown('SIGINT'));

process.on('unhandledRejection', (reason) => {
  logger.error({ reason }, 'Unhandled promise rejection in ctx-health');
});

// ─── Boot ────────────────────────────────────────────────────────────────────

void startup().catch((err) => {
  logger.error({ err }, 'Fatal startup error');
  process.exit(1);
});