const express = require('express');
const queue = require('../queue/queue');
const { renderDashboardPage } = require('./dashboard/page');

function toIsoFromEpochSeconds(epochSeconds) {
  if (epochSeconds === null || epochSeconds === undefined) return null;
  const value = Number(epochSeconds);
  if (!Number.isFinite(value) || value <= 0) return null;
  return new Date(value * 1000).toISOString();
}

function createDashboardRouter(connectors = []) {
  const router = express.Router();

  router.get('/', (req, res) => {
    res.type('html').send(renderDashboardPage());
  });

  router.get('/api/summary', async (req, res) => {
    const [pending, retrying, deadLetters, attempts, avgLatency] = await Promise.all([
      queue.pendingCount(),
      queue.retryingCount(),
      queue.deadLetterCount(),
      queue.getDeliveryAttempts(),
      queue.getAverageLatency()
    ]);

    res.json({
      status: 'ok',
      metrics: {
        pending,
        retrying,
        deadLetters,
        attempts,
        avgLatency
      }
    });
  });

  router.get('/api/queue', async (req, res) => {
    const limit = Number(req.query.limit || 20);
    const rows = await queue.listOutbox({ limit });
    res.json({
      status: 'ok',
      items: rows.map((row) => ({
        ...row,
        next_attempt_at_iso: toIsoFromEpochSeconds(row.next_attempt_at)
      }))
    });
  });

  router.get('/api/instruments', async (req, res) => {
    const items = connectors.map((connector) => {
      const status = connector.health();
      const address = status.comPort
        || status.port
        || [status.remoteAddress, status.remotePort].filter(Boolean).join(':')
        || '-';
      return {
        instrument_id: status.instrument_id || null,
        connector: connector.type(),
        status: status.status,
        address
      };
    });

    res.json({ status: 'ok', items });
  });

  router.get('/api/recent', async (req, res) => {
    const limit = Number(req.query.limit || 20);
    const items = await queue.listRecentDeliveryAttempts(limit);
    res.json({ status: 'ok', items });
  });

  return router;
}

module.exports = { createDashboardRouter };