+ // We don't exclude results in this so if we do a count we don't need to add this complex clause
+ if (options.isCount !== true) {
+ if (options.trendingDays) {
+ const viewsGteDate = new Date(new Date().getTime() - (24 * 3600 * 1000) * options.trendingDays)
+
+ joins.push('LEFT JOIN "videoView" ON "video"."id" = "videoView"."videoId" AND "videoView"."startDate" >= :viewsGteDate')
+ replacements.viewsGteDate = viewsGteDate
+
+ attributes.push('COALESCE(SUM("videoView"."views"), 0) AS "score"')
+
+ group = 'GROUP BY "video"."id"'
+ } else if ([ 'best', 'hot' ].includes(options.trendingAlgorithm)) {
+ /**
+ * "Hotness" is a measure based on absolute view/comment/like/dislike numbers,
+ * with fixed weights only applied to their log values.
+ *
+ * This algorithm gives little chance for an old video to have a good score,
+ * for which recent spikes in interactions could be a sign of "hotness" and
+ * justify a better score. However there are multiple ways to achieve that
+ * goal, which is left for later. Yes, this is a TODO :)
+ *
+ * notes:
+ * - weights and base score are in number of half-days.
+ * - all comments are counted, regardless of being written by the video author or not
+ * see https://github.com/reddit-archive/reddit/blob/master/r2/r2/lib/db/_sorts.pyx#L47-L58
+ * - we have less interactions than on reddit, so multiply weights by an arbitrary factor
+ */
+ const weights = {
+ like: 3 * 50,
+ dislike: -3 * 50,
+ view: Math.floor((1 / 3) * 50),
+ comment: 2 * 50, // a comment takes more time than a like to do, but can be done multiple times
+ history: -2 * 50
+ }
+
+ joins.push('LEFT JOIN "videoComment" ON "video"."id" = "videoComment"."videoId"')
+
+ let attribute =
+ `LOG(GREATEST(1, "video"."likes" - 1)) * ${weights.like} ` + // likes (+)
+ `+ LOG(GREATEST(1, "video"."dislikes" - 1)) * ${weights.dislike} ` + // dislikes (-)
+ `+ LOG("video"."views" + 1) * ${weights.view} ` + // views (+)
+ `+ LOG(GREATEST(1, COUNT(DISTINCT "videoComment"."id"))) * ${weights.comment} ` + // comments (+)
+ '+ (SELECT (EXTRACT(epoch FROM "video"."publishedAt") - 1446156582) / 47000) ' // base score (in number of half-days)
+
+ if (options.trendingAlgorithm === 'best' && options.user) {
+ joins.push(
+ 'LEFT JOIN "userVideoHistory" ON "video"."id" = "userVideoHistory"."videoId" AND "userVideoHistory"."userId" = :bestUser'
+ )
+ replacements.bestUser = options.user.id