import express              from 'express'
import { resolve, dirname } from 'path'
import { fileURLToPath }    from 'url'
import { cfg }              from './config.mjs'
import { queryCurrent, queryHourly, queryDaily, getCoords } from './influx.mjs'
import { getCelestialCurrent, getCelestialHourly, getCelestialDaily } from './celestial.mjs'
import { getSpaceWeather }  from './space.mjs'
import { getOpenMeteo }     from './openmeteo.mjs'
import { apiReference } from '@scalar/express-api-reference'
import { spec } from './spec.mjs'
import { existsSync } from 'fs'

const app = express()
const DIR = dirname(fileURLToPath(import.meta.url))
const CLIENT_DIST = resolve(DIR, 'public')

app.use(express.json())
app.use('/icons', express.static(resolve(DIR, 'public', 'icons')))
app.use((req, res, next) => { res.setHeader('Access-Control-Allow-Origin', '*'); next() })
app.use(express.static(CLIENT_DIST))

function filterFields(obj, fields) {
  if (!fields) return obj
  const keys = new Set(fields.split(',').map(f => f.trim()))
  return Object.fromEntries(Object.entries(obj).filter(([k]) => keys.has(k)))
}

function filterArr(arr, fields) {
  if (!fields) return arr
  return arr.map(row => filterFields(row, fields))
}

function mergeRows(arrays) {
  const map = {}
  for (const arr of arrays) {
    for (const row of arr) {
      map[row.time] = { ...map[row.time], ...row }
    }
  }
  return Object.values(map).sort((a, b) => a.time.localeCompare(b.time))
}

// ── GET /api/data ─────────────────────────────────────────────────────────────

app.get('/api/data', async (req, res) => {
  const { fields } = req.query
  const coords = await getCoords()

  const [sensor, space, meteo] = await Promise.allSettled([
    queryCurrent(),
    getSpaceWeather(),
    getOpenMeteo(coords.lat, coords.lon),
  ])

  const celestial = getCelestialCurrent(coords.lat, coords.lon)

  const data = {
    gps_lat: coords.lat,
    gps_lon: coords.lon,
    gps_alt: coords.alt,
    ...(sensor.status === 'fulfilled' ? sensor.value : {}),
    ...celestial,
    ...(space.status  === 'fulfilled' ? space.value  : {}),
    ...(meteo.status  === 'fulfilled' && meteo.value.current ? meteo.value.current : {}),
  }

  res.json(filterFields(data, fields))
})

// ── GET /api/hourly ───────────────────────────────────────────────────────────
app.get('/api/hourly', async (req, res) => {
  const { fields } = req.query
  const start  = req.query.start || new Date(new Date().setHours(0,0,0,0)).toISOString()
  const end    = req.query.end   || new Date().toISOString()
  const coords = await getCoords()

  const [sensor, meteo, space] = await Promise.allSettled([
    queryHourly(start, end),
    getOpenMeteo(coords.lat, coords.lon, start, end),
    getSpaceWeather(),
  ])

  const sensorRows  = sensor.status === 'fulfilled' ? sensor.value       : []
  const meteoHourly = meteo.status  === 'fulfilled' ? meteo.value.hourly : []
  const spaceData   = space.status  === 'fulfilled' ? space.value        : {}
  const seedRows    = sensorRows.length ? sensorRows : meteoHourly
  const celestial   = getCelestialHourly(coords.lat, coords.lon, seedRows)

  // Spread space weather into every hourly row
  const result = mergeRows([sensorRows, meteoHourly, celestial])
    .map(row => ({ gps_lat: coords.lat, gps_lon: coords.lon, gps_alt: coords.alt, ...spaceData, ...row }))

  res.json(filterArr(result, fields))
})

// ── GET /api/daily ------------------------------------------------------------

app.get('/api/daily', async (req, res) => {
  const { fields } = req.query
  const start  = req.query.start || new Date(new Date().setHours(0,0,0,0)).toISOString()
  const end    = req.query.end   || new Date().toISOString()
  const coords = await getCoords()

  const [sensor, meteo, space] = await Promise.allSettled([
    queryDaily(start, end),
    getOpenMeteo(coords.lat, coords.lon, start, end),
    getSpaceWeather(),
  ])

  const sensorRows = sensor.status === 'fulfilled' ? sensor.value      : []
  const meteoDaily = meteo.status  === 'fulfilled' ? meteo.value.daily : []
  const spaceData  = space.status  === 'fulfilled' ? space.value       : {}
  const seedRows   = sensorRows.length ? sensorRows : meteoDaily
  const celestial  = getCelestialDaily(coords.lat, coords.lon, seedRows)

  const result = mergeRows([sensorRows, meteoDaily, celestial])
    .map(row => ({ location: coords,gps_lat: coords.lat, gps_lon: coords.lon, gps_alt: coords.alt, ...spaceData, ...row }))

  res.json(filterArr(result, fields))
})

// ── DOCS ----------------------------------------------------------------------

app.get('/openapi.json', (req, res) => res.json(spec))
app.get('/openapi.yaml', async (req, res) => {
  const { stringify } = await import('yaml')
  res.setHeader('Content-Type', 'text/yaml')
  res.send(stringify(spec))
})

// Scalar UI
app.use('/docs', apiReference({ spec: { url: '/openapi.json' }, theme: 'default' }))


// ── SPA Redirect --------------------------------------------------------------
  app.get('*', (req, res) => {
  const index = resolve(CLIENT_DIST, 'index.html')
  if (existsSync(index)) res.sendFile(index)
  else res.status(404).send('Client not built yet — run npm run build in /client')
})

// ── Start ─────────────────────────────────────────────────────────────────────

const c = cfg()
app.listen(c.PORT, () => console.log(`🌦  Weather API — http://localhost:${c.PORT}`))