#!/usr/bin/env node
// scheduler.mjs — Spor C / C1 Tier 2: install/manage the local launchd
// LaunchAgent that runs the Claude-FREE detection pipeline on a daily schedule,
// independent of Claude sessions = real background BETWEEN sessions.
//
// STRUCTURAL ToS GUARANTEE: this script only ever spawns the running node
// binary (process.execPath) on the allow-listed run-detection.mjs, and the
// `launchctl` CLI for agent management. It can NEVER invoke `claude`. The
// scheduled entrypoint (`run`) gates on cadence, then delegates to
// run-detection.mjs, which is itself structurally Claude-free. Apply (the only
// Claude step) stays manual + in-session + gated. See detection-schedule.mjs
// for the ToS rationale (Consumer Terms §3.7 targets Anthropic's services, not
// local scripts).
//
//   node scripts/kb-update/scheduler.mjs install     # write plist + load agent
//   node scripts/kb-update/scheduler.mjs uninstall    # unload + remove plist
//   node scripts/kb-update/scheduler.mjs status        # is it loaded?
//   node scripts/kb-update/scheduler.mjs run-now        # trigger one run now
//   node scripts/kb-update/scheduler.mjs print          # show the plist (alias --dry-run)
//   node scripts/kb-update/scheduler.mjs run            # (the launchd entrypoint)

import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { homedir } from 'node:os';
import { existsSync, readFileSync, mkdirSync, rmSync } from 'node:fs';
import { execFileSync } from 'node:child_process';
import { renderPlist, resolvePaths, defaultLabel } from './lib/launchd-plist.mjs';
import {
  loadScheduleConfig,
  daysSinceLastPoll,
} from './lib/detection-schedule.mjs';
import { atomicWriteSync } from './lib/atomic-write.mjs';

const __dirname = dirname(fileURLToPath(import.meta.url));
const PLUGIN_ROOT = join(__dirname, '..', '..');
const RUN_DETECTION = join(PLUGIN_ROOT, 'scripts', 'kb-update', 'run-detection.mjs');
const CHANGE_REPORT = join(PLUGIN_ROOT, 'scripts', 'kb-update', 'data', 'change-report.json');

// Daily fire time. Not configurable yet (onboarding/C2 may expose it).
const FIRE_HOUR = 3;
const FIRE_MINUTE = 0;

/** Build renderPlist inputs from the resolved paths + the running node. */
function planAgent() {
  const nodePath = process.execPath;
  const paths = resolvePaths({ pluginRoot: PLUGIN_ROOT, homeDir: homedir(), nodePath });
  const plist = renderPlist({
    label: paths.label,
    nodePath,
    scriptPath: paths.scriptPath,
    args: ['run'],
    hour: FIRE_HOUR,
    minute: FIRE_MINUTE,
    logPath: paths.logPath,
    workingDir: paths.workingDir,
  });
  return { ...paths, nodePath, plist };
}

/** gui/<uid> domain + gui/<uid>/<label> service target. */
function targets() {
  const uid = process.getuid();
  return { domain: `gui/${uid}`, service: `gui/${uid}/${defaultLabel()}` };
}

/**
 * Run launchctl. ignoreError swallows a non-zero exit (the idempotency
 * primitive — a pre-install bootout of a not-yet-loaded service is expected to
 * fail); silent hides its output so that expected failure isn't alarming.
 */
function launchctl(args, { ignoreError = false, silent = false } = {}) {
  try {
    execFileSync('launchctl', args, { stdio: silent ? 'ignore' : 'inherit' });
    return true;
  } catch (err) {
    if (ignoreError) return false;
    throw err;
  }
}

// --- Subcommands -----------------------------------------------------------

function printPlist() {
  // Pure preview: render and print. Writes nothing, runs no launchctl.
  process.stdout.write(planAgent().plist);
}

function install() {
  if (typeof process.getuid === 'function' && process.getuid() === 0) {
    console.error('Refusing to install as root — run as your logged-in user (no sudo).');
    console.error('A LaunchAgent in the gui/<uid> domain must target your own session.');
    process.exit(1);
  }
  const { agentPlistPath, plist, scriptPath, logPath } = planAgent();
  const { domain, service } = targets();

  mkdirSync(dirname(agentPlistPath), { recursive: true });
  atomicWriteSync(agentPlistPath, plist);

  // Idempotent: unload any previous instance (expected to fail+silent on first install).
  launchctl(['bootout', service], { ignoreError: true, silent: true });
  launchctl(['bootstrap', domain, agentPlistPath]);

  console.log(`Installed LaunchAgent: ${agentPlistPath}`);
  console.log(`  fires daily at ${String(FIRE_HOUR).padStart(2, '0')}:${String(FIRE_MINUTE).padStart(2, '0')} → ${scriptPath} run`);
  console.log(`  log: ${logPath}`);
  console.log('');
  console.log('Verify now:  node scripts/kb-update/scheduler.mjs run-now');
  console.log('Pause it:    node scripts/kb-update/scheduler.mjs uninstall   (the enabled: flag is Tier-1/hook only)');
  console.log('After a major `brew upgrade node`, re-run install (the node path is pinned at install time).');
}

function uninstall() {
  const { agentPlistPath } = planAgent();
  const { service } = targets();
  launchctl(['bootout', service], { ignoreError: true, silent: true });
  if (existsSync(agentPlistPath)) {
    rmSync(agentPlistPath);
    console.log(`Removed LaunchAgent: ${agentPlistPath}`);
  } else {
    console.log('No LaunchAgent plist found — nothing to remove.');
  }
}

function status() {
  const { agentPlistPath } = planAgent();
  const { service } = targets();
  console.log(`plist: ${agentPlistPath} ${existsSync(agentPlistPath) ? '(present)' : '(absent)'}`);
  // Non-fatal: prints the loaded job, or an error line if not loaded.
  launchctl(['print', service], { ignoreError: true });
}

function runNow() {
  const { service } = targets();
  launchctl(['kickstart', '-k', service]);
  console.log(`Kicked off ${service} — see the log for output.`);
}

/** The launchd entrypoint. Gate on cadence, then delegate to run-detection.mjs. */
function run() {
  const config = loadScheduleConfig(PLUGIN_ROOT);
  if (config.os_scheduler_cadence === 'interval') {
    let report = null;
    if (existsSync(CHANGE_REPORT)) {
      try {
        report = JSON.parse(readFileSync(CHANGE_REPORT, 'utf8'));
      } catch {
        report = null; // unreadable => treat as infinitely stale => run
      }
    }
    const days = daysSinceLastPoll(report, Date.now());
    if (days < config.interval_days) {
      console.log(`fresh (${Math.floor(days)}d < ${config.interval_days}d) — skipping poll`);
      return;
    }
  }
  // daily cadence, or interval+stale: delegate to the Claude-free entrypoint
  // using the running node binary (no PATH dependency for this hop).
  execFileSync(process.execPath, [RUN_DETECTION], { stdio: 'inherit' });
}

// --- Dispatch --------------------------------------------------------------

const cmd = process.argv[2];
switch (cmd) {
  case 'print':
  case '--dry-run':
    printPlist();
    break;
  case 'install':
    install();
    break;
  case 'uninstall':
    uninstall();
    break;
  case 'status':
    status();
    break;
  case 'run-now':
    runNow();
    break;
  case 'run':
    run();
    break;
  default:
    console.error('Usage: scheduler.mjs <install|uninstall|status|run-now|print|run>');
    process.exit(2);
}