overleaf/services/track-changes/app/js/ProjectIterator.js

/* eslint-disable
    no-unmodified-loop-condition,
    no-unused-vars,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
 * decaffeinate suggestions:
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
let ProjectIterator
const Heap = require('heap')

module.exports = ProjectIterator = ProjectIterator = class ProjectIterator {
  constructor(packs, before, getPackByIdFn) {
    this.before = before
    this.getPackByIdFn = getPackByIdFn
    const byEndTs = (a, b) =>
      b.meta.end_ts - a.meta.end_ts || a.fromIndex - b.fromIndex
    this.packs = packs.slice().sort(byEndTs)
    this.queue = new Heap(byEndTs)
  }

  next(callback) {
    //  what's up next
    // console.log ">>> top item", iterator.packs[0]
    const iterator = this
    const { before } = this
    const { queue } = iterator
    const opsToReturn = []
    let nextPack = iterator.packs[0]
    let lowWaterMark =
      (nextPack != null ? nextPack.meta.end_ts : undefined) || 0
    let nextItem = queue.peek()

    // console.log "queue empty?", queue.empty()
    // console.log "nextItem", nextItem
    // console.log "nextItem.meta.end_ts", nextItem?.meta.end_ts
    // console.log "lowWaterMark", lowWaterMark

    while (
      before != null &&
      (nextPack != null ? nextPack.meta.start_ts : undefined) > before
    ) {
      // discard pack that is outside range
      iterator.packs.shift()
      nextPack = iterator.packs[0]
      lowWaterMark = (nextPack != null ? nextPack.meta.end_ts : undefined) || 0
    }

    if (
      (queue.empty() ||
        (nextItem != null ? nextItem.meta.end_ts : undefined) <=
          lowWaterMark) &&
      nextPack != null
    ) {
      // retrieve the next pack and populate the queue
      return this.getPackByIdFn(
        nextPack.project_id,
        nextPack.doc_id,
        nextPack._id,
        function(err, pack) {
          if (err != null) {
            return callback(err)
          }
          iterator.packs.shift() // have now retrieved this pack, remove it
          // console.log "got pack", pack
          for (const op of Array.from(pack.pack)) {
            // console.log "adding op", op
            if (before == null || op.meta.end_ts < before) {
              op.doc_id = nextPack.doc_id
              op.project_id = nextPack.project_id
              queue.push(op)
            }
          }
          // now try again
          return iterator.next(callback)
        }
      )
    }

    // console.log "nextItem", nextItem, "lowWaterMark", lowWaterMark
    while (
      nextItem != null &&
      (nextItem != null ? nextItem.meta.end_ts : undefined) > lowWaterMark
    ) {
      opsToReturn.push(nextItem)
      queue.pop()
      nextItem = queue.peek()
    }

    // console.log "queue empty?", queue.empty()
    // console.log "nextPack", nextPack?

    if (queue.empty() && nextPack == null) {
      // got everything
      iterator._done = true
    }

    return callback(null, opsToReturn)
  }

  done() {
    return this._done
  }
}