'use strict'
const cfg = require('./config')
const { log, json, parseBody } = require('./helpers')

const authHeader = 'Basic ' + Buffer.from(cfg.TRACCAR_USER + ':' + cfg.TRACCAR_PASS).toString('base64')

async function traccarFetch (path) {
  const res = await fetch(cfg.TRACCAR_URL + path, {
    headers: { Authorization: authHeader, Accept: 'application/json' },
  })
  if (!res.ok) throw new Error(`Traccar ${res.status}: ${path}`)
  return res.json()
}

// Cache devices for 60s (they rarely change)
let _devCache = null, _devCacheTs = 0
async function getDevices () {
  if (_devCache && Date.now() - _devCacheTs < 60000) return _devCache
  _devCache = await traccarFetch('/api/devices?all=true')
  _devCacheTs = Date.now()
  return _devCache
}

async function getPositions (deviceIds) {
  if (!deviceIds?.length) return []
  const results = await Promise.allSettled(
    deviceIds.map(id => traccarFetch('/api/positions?deviceId=' + id))
  )
  return results.flatMap(r => r.status === 'fulfilled' ? r.value : [])
}

async function handle (req, res, method, path) {
  const sub = path.replace('/traccar', '').replace(/^\//, '')

  if (sub === 'devices' && method === 'GET') {
    try {
      return json(res, 200, await getDevices())
    } catch (e) {
      log('Traccar devices error:', e.message)
      return json(res, 502, { error: 'Traccar unavailable' })
    }
  }

  if (sub === 'positions' && method === 'GET') {
    try {
      const url = new URL(req.url, 'http://localhost')
      const ids = (url.searchParams.get('deviceIds') || '').split(',').map(Number).filter(Boolean)
      return json(res, 200, await getPositions(ids))
    } catch (e) {
      log('Traccar positions error:', e.message)
      return json(res, 502, { error: 'Traccar unavailable' })
    }
  }

  // Proxy any other Traccar API path (fallback)
  if (method === 'GET') {
    try {
      return json(res, 200, await traccarFetch('/api/' + sub))
    } catch (e) {
      return json(res, 502, { error: e.message })
    }
  }

  json(res, 404, { error: 'Traccar endpoint not found' })
}

module.exports = { handle, getDevices, getPositions }