const express = require('express')
const bodyParser = require('body-parser')
const fetch = require('node-fetch')
const crypto = require('crypto')

const PORT = process.env.PORT || 7201
const SUPA_URL = (process.env.SUPA_URL || process.env.SUPA_URL_OVERRIDE || '').replace(/\/$/, '')
const SUPA_KEY = process.env.SUPA_KEY || process.env.SERVICE_ROLE_KEY || ''
const WEBHOOK_SECRET = process.env.WEBHOOK_SECRET || '' // optional HMAC secret

function supaFetch(path, opts = {}) {
  const url = `${SUPA_URL}/rest/v1/${path}`
  const headers = Object.assign({}, opts.headers || {}, {
    apikey: SUPA_KEY,
    Authorization: `Bearer ${SUPA_KEY}`,
    Accept: 'application/json'
  })
  return fetch(url, Object.assign({}, opts, { headers }))
}

function computeSignature(bodyText, ts) {
  if (!WEBHOOK_SECRET) return ''
  const h = crypto.createHmac('sha256', WEBHOOK_SECRET)
  h.update(bodyText + (ts || ''))
  return h.digest('hex')
}

async function upsertRaw(payload, tracking_no, carrier, signature_valid) {
  try {
    const body = {
      carrier: carrier || null,
      tracking_no: tracking_no || null,
      body: payload,
      received_at: new Date().toISOString(),
      signature_valid: signature_valid
    }
    const resp = await supaFetch('platform_express_event_raw', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(body)
    })
    return resp
  } catch (e) {
    console.warn('upsertRaw error', e)
    return null
  }
}

async function findWaybillId(tracking_no, order_no) {
  try {
    if (tracking_no) {
      const r = await supaFetch(`platform_express_waybills?tracking_no=eq.${encodeURIComponent(tracking_no)}`)
      if (r.ok) {
        const data = await r.json()
        if (data && data.length > 0) return data[0].id
      }
    }
    if (order_no) {
      const r2 = await supaFetch(`platform_express_waybills?order_no=eq.${encodeURIComponent(order_no)}`)
      if (r2.ok) {
        const data2 = await r2.json()
        if (data2 && data2.length > 0) return data2[0].id
      }
    }
    return null
  } catch (e) {
    console.warn('findWaybillId error', e)
    return null
  }
}

function mapStatus(inStatus) {
  let s = 'IN_TRANSIT'
  if (!inStatus) return s
  const v = String(inStatus).toUpperCase()
  if (['GOT','SEND','TRANSIT'].indexOf(v) > -1) s = 'IN_TRANSIT'
  else if (v === 'SENT') s = 'OUT_FOR_DELIVERY'
  else if (v === 'PICKUP') s = 'READY_FOR_PICKUP'
  else if (v === 'SIGNED' || v === 'DELIVERED') s = 'DELIVERED'
  else if (v === 'FAILED' || v === 'EXCEPTION') s = 'EXCEPTION'
  else if (v === 'RETURNED') s = 'RETURNED'
  else {
    const valid = ['ORDER_PLACED','SHIPPED','IN_TRANSIT','OUT_FOR_DELIVERY','READY_FOR_PICKUP','DELIVERED','EXCEPTION','RETURNED']
    if (valid.indexOf(v) > -1) s = v
  }
  return s
}

async function updateWaybill(id, status_code, text) {
  try {
    const now = new Date().toISOString()
    await supaFetch(`platform_express_waybills?id=eq.${encodeURIComponent(id)}`, {
      method: 'PATCH',
      headers: { 'Content-Type': 'application/json', Prefer: 'return=representation' },
      body: JSON.stringify({ current_status_code: status_code, current_status_text: text, last_synced_at: now })
    })
  } catch (e) {
    console.warn('updateWaybill error', e)
  }
}

async function insertEvent(event) {
  try {
    await supaFetch('platform_express_tracking_events', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(event)
    })
  } catch (e) { console.warn('insertEvent error', e) }
}

async function start() {
  if (!SUPA_URL || !SUPA_KEY) {
    console.error('SUPA_URL and SUPA_KEY must be set in env')
    process.exit(1)
  }

  const app = express()
  app.use(bodyParser.json({ limit: '1mb' }))

  app.post('/webhook/express/status', async (req, res) => {
    const ts = req.headers['x-timestamp'] || req.headers['X-TIMESTAMP'] || ''
    const sig = req.headers['x-signature'] || req.headers['X-SIGNATURE'] || ''
    const cid = req.headers['x-client-id'] || req.headers['X-CLIENT-ID'] || ''
    const bodyText = JSON.stringify(req.body || {})

    let sigValid = true
    if (WEBHOOK_SECRET) {
      const calc = computeSignature(bodyText, ts)
      sigValid = calc === String(sig)
    }

    // persist raw
    await upsertRaw(req.body || {}, req.body && (req.body.mailNo || req.body.tracking_no), req.body && req.body.carrier, sigValid)

    // find waybill
    const tracking_no = req.body && (req.body.mailNo || req.body.tracking_no)
    const order_no = req.body && (req.body.txLogisticId || req.body.order_no)
    const carrier = req.body && req.body.carrier ? req.body.carrier : (req.body && req.body.company || null)
    const event_code = req.body && (req.body.infoContent || req.body.status_code || req.body.event_code)
    const event_text = req.body && (req.body.remark || req.body.event_text || '')

    const waybillId = await findWaybillId(tracking_no, order_no)
    if (!waybillId) {
      // Waybill not found — respond 200 but inform caller in body.
      return res.status(200).json({ ok: false, message: 'waybill not found' })
    }

    const status_code = mapStatus(event_code)

    // update waybill
    await updateWaybill(waybillId, status_code, event_text)

    // parse event_time
    let event_time = new Date().toISOString()
    if (req.body && req.body.acceptTime) {
      try {
        const t = req.body.acceptTime.indexOf('T') > -1 ? req.body.acceptTime : req.body.acceptTime.replace(' ', 'T')
        const dt = new Date(t)
        if (!isNaN(dt.getTime())) event_time = dt.toISOString()
      } catch (e) {}
    }

    // insert event
    const eventPayload = {
      waybill_id: waybillId,
      carrier: carrier,
      tracking_no: tracking_no || null,
      event_time: event_time,
      event_code: event_code || 'UNKNOWN',
      event_text: event_text || '',
      status_code: status_code,
      raw_payload: req.body || {},
      dedupe_key: 'WEBHOOK_' + Date.now()
    }
    await insertEvent(eventPayload)

    return res.json({ ok: true })
  })

  app.get('/health', (req, res) => res.json({ ok: true }))

  app.listen(PORT, '0.0.0.0', () => console.log(`Webhook receiver listening on http://0.0.0.0:${PORT}`))
}

start().catch(e => { console.error('start failed', e); process.exit(1) })