overleaf/services/document-updater/app/coffee/TrackChangesManager.coffee

settings = require "settings-sharelatex"
request  = require "request"
logger = require "logger-sharelatex"
redis = require("redis-sharelatex")
rclient = redis.createClient(settings.redis.web)
async = require "async"

module.exports = TrackChangesManager =
	flushDocChanges: (project_id, doc_id, callback = (error) ->) ->
		if !settings.apis?.trackchanges?
			logger.warn doc_id: doc_id, "track changes API is not configured, so not flushing"
			return callback()

		url = "#{settings.apis.trackchanges.url}/project/#{project_id}/doc/#{doc_id}/flush"
		logger.log project_id: project_id, doc_id: doc_id, url: url, "flushing doc in track changes api"
		request.post url, (error, res, body)->
			if error?
				return callback(error)
			else if res.statusCode >= 200 and res.statusCode < 300
				return callback(null)
			else
				error = new Error("track changes api returned a failure status code: #{res.statusCode}")
				return callback(error)

	FLUSH_EVERY_N_OPS: 50
	pushUncompressedHistoryOp: (project_id, doc_id, op, callback = (error) ->) ->
		jsonOp = JSON.stringify op
		multi = rclient.multi()
		multi.rpush "UncompressedHistoryOps:#{doc_id}", jsonOp
		multi.sadd "DocsWithHistoryOps:#{project_id}", doc_id
		multi.exec (error, results) ->
			return callback(error) if error?
			[length, _] = results
			if length > 0 and length % TrackChangesManager.FLUSH_EVERY_N_OPS == 0
				# Do this in the background since it uses HTTP and so may be too
				# slow to wait for when processing a doc update.
				logger.log length: length, doc_id: doc_id, project_id: project_id, "flushing track changes api"
				TrackChangesManager.flushDocChanges project_id, doc_id,  (error) ->
					if error?
						logger.error err: error, doc_id: doc_id, project_id: project_id, "error flushing doc to track changes api"
			callback()