const admin = require('firebase-admin')
const { FieldValue } = require('firebase-admin/firestore')
const { onDocumentWritten } = require('firebase-functions/firestore')
const _ = require('lodash')
const { refList, db } = require('../index')
const { SUNO_API_KEY } = require('../config/secrets')
const { getSunoTimestamps } = require('./lyrics')
const { deleteFolder } = require('../helpers/firebase')
const { buildMonthKey } = require('../helpers/stats')

const PROJECT_FUNCTION_OPTIONS = {
  document: 'projects/{projectId}',
  secrets: [SUNO_API_KEY],
}

exports.onProjectWritten = onDocumentWritten(PROJECT_FUNCTION_OPTIONS, async (projectSnap) => {
  try {
    const { projectId } = projectSnap.params
    const beforeData = projectSnap?.data?.before?.data() || null
    const afterData = projectSnap?.data?.after?.data() || null

    if (!afterData) {
      const { userId } = beforeData || {}

      if (userId) {
        await deleteFolder(`users/${userId}/projects/${projectId}/`)
      }

      const snapshot = await refList.tasks.where('projectId', '==', projectId).get()
      if (!snapshot.empty) {
        const batch = db.batch()
        snapshot.forEach((doc) => {
          batch.delete(doc.ref)
        })
        await batch.commit()
      }

      return null
    } else if (!beforeData) {
      //song create
    } else {
      const selectedSongChanged =
        !!afterData?.songUrl &&
        (beforeData?.songUrl !== afterData.songUrl ||
          beforeData?.sunoAudioId !== afterData?.sunoAudioId)

      if (selectedSongChanged) {
        await getSunoTimestamps(projectId)
        await refList.projects.doc(projectId).update({ hasSong: true })
      }

      if (!beforeData?.playbackUrl && afterData?.playbackUrl) {
        await refList.projects.doc(projectId).update({ hasPlayback: true })
      }
    }

    const beforeViews = _.toFinite(_.get(beforeData, 'views', 0))
    const afterViews = _.toFinite(_.get(afterData, 'views', 0))
    const delta = afterViews - beforeViews

    if (delta > 0) {
      const userIdRaw = _.get(afterData, 'userId', null)
      const userId = _.isString(userIdRaw) && _.trim(userIdRaw).length ? _.trim(userIdRaw) : null
      const now = admin.firestore.Timestamp.now()
      const monthKey = buildMonthKey(now)

      const statsDocRef = refList.projectStreamStats
        .doc(projectId)
        .collection('monthlyListens')
        .doc(monthKey)
      const projectsRef = refList.projects.doc(projectId)


      const totalsDocRef = refList.projectStreamStatsMonthlyTotals.doc(monthKey)

      await db.runTransaction(async (transaction) => {
        const statsSnapshot = await transaction.get(statsDocRef)
        const totalsSnapshot = await transaction.get(totalsDocRef)
        const updatePayload = {
          projectId,
          userId,
          monthKey,
          updatedAt: now,
          lastStreamAt: now,
          lastDelta: delta,
          streams: FieldValue.increment(delta),
        }

        const hasFirstStream = statsSnapshot.exists && statsSnapshot.data()?.firstStreamAt
        if (!hasFirstStream) {
          updatePayload.firstStreamAt = now
        }

        transaction.set(statsDocRef, updatePayload, { merge: true })
        transaction.set(projectsRef, { monthViews: FieldValue.increment(delta) }, { merge: true })

        const totalsUpdatePayload = {
          monthKey,
          updatedAt: now,
          lastStreamAt: now,
          lastDelta: delta,
          totalStreams: FieldValue.increment(delta),
        }
        const totalsHasFirstStream = totalsSnapshot.exists && totalsSnapshot.data()?.firstStreamAt
        if (!totalsHasFirstStream) {
          totalsUpdatePayload.firstStreamAt = now
        }
        transaction.set(totalsDocRef, totalsUpdatePayload, { merge: true })
      })
    }

    return null
  } catch (error) {
    console.log('onProjectViewsIncrement error', {
      message: error?.message || String(error || ''),
    })
    return null
  }
})