/**
 * Operator HTTP: list, status, pause/resume/stop/start/restart.
 * Binds 127.0.0.1 only.
 * @module server
 */

import http from 'node:http';
import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { listServices } from './load.js';
import { ACTIONS, Simulator } from '../../verae-zapier-simulator/src/pipeline.js';

const PUBLIC = path.join(path.dirname(fileURLToPath(import.meta.url)), '..', 'public');

function json(res, code, obj) {
  res.writeHead(code, { 'content-type': 'application/json', 'cache-control': 'no-store' });
  res.end(JSON.stringify(obj, null, 2));
}

/**
 * @param {import('./supervisor.js').Supervisor} sup
 * @param {import('./monitor.js').Monitor} [mon]
 */
export function startControlServer(sup, mon) {
  const bind = sup.loaded.control?.bind || '127.0.0.1';
  const port = Number(sup.loaded.control?.port || 3850);
  const sim = new Simulator();

  const server = http.createServer(async (req, res) => {
    const url = new URL(req.url, `http://${bind}:${port}`);
    try {
      if (req.method === 'GET' && url.pathname === '/health') {
        return json(res, 200, { ok: true, role: 'operator-console' });
      }
      if (req.method === 'GET' && url.pathname === '/api/sim/actions') {
        return json(res, 200, { actions: ACTIONS, state: sim.snapshot() });
      }
      if (req.method === 'POST' && url.pathname === '/api/sim/reset') {
        sim.reset();
        return json(res, 200, { ok: true, state: sim.snapshot() });
      }
      if (req.method === 'POST' && url.pathname === '/api/sim/run') {
        const chunks = [];
        for await (const c of req) chunks.push(c);
        const body = JSON.parse(Buffer.concat(chunks).toString('utf8') || '{}');
        const result = await sim.run(body);
        return json(res, 200, result);
      }
      if (req.method === 'GET' && url.pathname === '/api/services') {
        return json(res, 200, { services: listServices(sup.loaded), fleetPath: sup.loaded.fleetPath });
      }
      if (req.method === 'GET' && url.pathname === '/api/status') {
        return json(res, 200, { ...sup.status(), monitor: mon?.last || null });
      }
      if (req.method === 'GET' && url.pathname === '/api/machines') {
        return json(res, 200, { machines: sup.status().machines });
      }
      if (req.method === 'POST' && url.pathname === '/api/machines') {
        const chunks = [];
        for await (const c of req) chunks.push(c);
        const spec = JSON.parse(Buffer.concat(chunks).toString('utf8') || '{}');
        const m = sup.addMachine(spec);
        return json(res, 200, { machine: m, machines: sup.status().machines });
      }
      const mach = url.pathname.match(/^\/api\/machines\/([^/]+)\/(enable|disable|check)$/);
      if (mach && req.method === 'POST') {
        const [, id, op] = mach;
        if (op === 'check') {
          const check = await sup.checkMachine(id);
          return json(res, check.ok ? 200 : 400, { check, machines: sup.status().machines });
        }
        const m = sup.setMachineEnabled(id, op === 'enable');
        return json(res, 200, { machine: m, machines: sup.status().machines });
      }
      if (req.method === 'POST' && url.pathname === '/api/reconcile') {
        const actions = await sup.reconcile();
        return json(res, 200, { actions, status: sup.status() });
      }
      const svc = url.pathname.match(/^\/api\/services\/([^/]+)\/(start|stop|pause|resume)$/);
      if (svc && req.method === 'POST') {
        const [, id, op] = svc;
        const fn = {
          start: () => sup.startService(id),
          stop: () => sup.stopService(id),
          pause: () => sup.pauseService(id),
          resume: () => sup.resumeService(id),
        }[op];
        const result = await fn();
        return json(res, 200, { op, id, result, status: sup.status().services[id] });
      }
      const inst = url.pathname.match(/^\/api\/instances\/([^/]+)\/(pause|resume|restart|stop|unhealthy)$/);
      if (inst && req.method === 'POST') {
        const [, id, op] = inst;
        const fn = {
          pause: () => sup.pauseInstance(id),
          resume: () => sup.resumeInstance(id),
          restart: () => sup.restartInstance(id),
          stop: () => sup.stopInstance(id, { replace: true }),
          unhealthy: () => sup.markUnhealthy(id),
        }[op];
        const result = await fn();
        return json(res, 200, { op, id, result: result?.id || result, status: sup.status() });
      }
      if (req.method === 'GET' && (url.pathname === '/' || url.pathname === '/index.html')) {
        const dest = path.join(PUBLIC, 'index.html');
        res.writeHead(200, { 'content-type': 'text/html; charset=utf-8' });
        fs.createReadStream(dest).pipe(res);
        return;
      }
      if (req.method === 'GET' && url.pathname.startsWith('/docs/')) {
        const dest = path.normalize(path.join(PUBLIC, '..', url.pathname));
        const root = path.normalize(path.join(PUBLIC, '..', 'docs'));
        if (
          !(dest === root || dest.startsWith(root + path.sep)) ||
          !fs.existsSync(dest) ||
          !fs.statSync(dest).isFile()
        ) {
          return json(res, 404, { error: 'not found' });
        }
        const ext = path.extname(dest).toLowerCase();
        const types = {
          '.png': 'image/png',
          '.jpg': 'image/jpeg',
          '.jpeg': 'image/jpeg',
          '.svg': 'image/svg+xml',
          '.pdf': 'application/pdf',
          '.md': 'text/markdown; charset=utf-8',
          '.html': 'text/html; charset=utf-8',
        };
        res.writeHead(200, { 'content-type': types[ext] || 'application/octet-stream' });
        fs.createReadStream(dest).pipe(res);
        return;
      }
      json(res, 404, { error: 'not found' });
    } catch (err) {
      json(res, 400, { error: err.message });
    }
  });

  server.listen(port, bind, () => {
    process.stdout.write(`fleet control http://${bind}:${port}/\n`);
  });
  return server;
}