const admin = require("firebase-admin");
const { onDocumentWritten } = require("firebase-functions/firestore");
const _ = require("lodash");
const { refList, db } = require("../index");
const { getSunoTimestamps } = require("./lyrics");
const { deleteFolder } = require("../helpers/firebase");
const { buildMonthKey } = require("../helpers/stats");

exports.onProjectWritten = onDocumentWritten(
  "projects/{projectId}",
  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 {
        if (!beforeData?.songUrl && afterData?.songUrl) {
          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 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: admin.firestore.FieldValue.increment(delta),
          };

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

          transaction.set(statsDocRef, updatePayload, { merge: true });

          const totalsUpdatePayload = {
            monthKey,
            updatedAt: now,
            lastStreamAt: now,
            lastDelta: delta,
            totalStreams: admin.firestore.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;
    }
  },
);