"use strict";

// manually adding next line gives me a more benign warning
// but I cannot find and docs saying this should be necessary
// process.env.GCLOUD_PROJECT = "tsapi-prod"
// process.env.GCLOUD_PROJECT = JSON.parse(process.env.FIREBASE_CONFIG).projectId

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();

exports.newCommFeedRecord = functions.database.ref('commNews/{date}/{window}/{record}')
  .onCreate((snap, context) => {
    var date = context.params.date;
    var window = context.params.window;
    var record = context.params.record;
    var mostRecentWindow = {}
    var leastRecentWindow = {}
    var commNewsInternal = {}
    var updatePaths = false

    console.log("new comm feed record written at " + date + " " + window + " " + record)

    // read most recent window values
    // grab global data mapping from firebase
    snap.ref.root.child('_commNewsInternal').once('value')
      .then((snapshot) => { 
        console.log("_commNewsInternal is: " + JSON.stringify(snapshot.val()));
        console.log("windows is: " + JSON.stringify(snapshot.val().windows));

        // copy internal data
        commNewsInternal = {
            total: snapshot.val().total,
            limit: snapshot.val().limit,
            windows: snapshot.val().windows,
        }

        if (commNewsInternal.total === undefined || commNewsInternal.limit === undefined) {
          console.log("need total and limit!");
          return false
        }

        // check for empty window list in firebase
        if (commNewsInternal.windows === undefined) {
          console.log("need to init windows!"); 

          // create new window entry
          var newWindow = {
            date: date, 
            window: window, 
            count: 0
          }
          commNewsInternal.windows = [newWindow]

          console.log("setting window list to: " + JSON.stringify(commNewsInternal.windows));
        } 

        // get most recent window 
        mostRecentWindow = commNewsInternal.windows[commNewsInternal.windows.length - 1]
        leastRecentWindow = commNewsInternal.windows[0]

        // (1) compare most recent window values
        if (date != mostRecentWindow.date 
          || window != mostRecentWindow.window) {
            console.log("need create new window/date for new comm feed record!"); 

          // create and append new window entry
          var newWindow = {
            date: date, 
            window: window, 
            count: 0,
          }
          commNewsInternal.windows.push(newWindow)

          // newest window is now the most recent window
          mostRecentWindow = newWindow

          // paths need to be updated
          updatePaths = true
        } 
 
        // (2) update the total count and mostRecentWindow count
        commNewsInternal.total += 1
        mostRecentWindow.count += 1

        if (mostRecentWindow == leastRecentWindow) {
          // NOTE: there is no need to update the path list
          console.log("only one window!"); 
        } else if (commNewsInternal.total - leastRecentWindow.count > commNewsInternal.limit) {
          // need to remove least recent window
          console.log("diff " + commNewsInternal.total - leastRecentWindow.count + " greater than limit!");

          // adjust total
          commNewsInternal.total -= leastRecentWindow.count

          // remove least recent window
          commNewsInternal.windows.shift()
          console.log("windows is now " + JSON.stringify(commNewsInternal.windows))

          // paths need to be updated
          updatePaths = true
        }

        console.log("updating comm news internal with " + JSON.stringify(commNewsInternal)); 
        return snap.ref.root.child('_commNewsInternal').update(commNewsInternal); 
      }).then(() => { 
        // (3) update active paths if needed   
        if (!updatePaths) {
          return true;
        } 

        console.log("need to update paths!");
        var paths = []
        for (var i = 0; i < commNewsInternal.windows.length; i++) {
            var path = "commNews/" + commNewsInternal.windows[i].date + "/" + commNewsInternal.windows[i].window
            paths.push(path)
        }

        console.log("updating commNews-activePaths with " + JSON.stringify(paths));
        return snap.ref.root.child('commNews-activePaths').set(paths);
      })
      .catch((error) => {
        console.error("failed to get windows data: " + error.message);
      });
    return true;
});