Merge pull request #2 from ajayyy/experimental

Added voting and new weighted random returns based on votes

index.js

@@ -33,23 +33,45 @@ app.get('/api/getVideoSponsorTimes', function (req, res) {
     let videoID = req.query.videoID;
 
     let sponsorTimes = [];
+    let votes = []
+    let UUIDs = [];
 
-    db.prepare("SELECT startTime, endTime FROM sponsorTimes WHERE videoID = ?").all(videoID, function(err, rows) {
+    db.prepare("SELECT startTime, endTime, votes, UUID FROM sponsorTimes WHERE videoID = ?").all(videoID, function(err, rows) {
         if (err) console.log(err);
 
         for (let i = 0; i < rows.length; i++) {
-            sponsorTimes[i] = [];
+            //check if votes are above -2
+            if (rows[i].votes < -2) {
+                //too untrustworthy, just ignore it
+                continue;
+            }
+            sponsorTimes.push([]);
+            
+            let index = sponsorTimes.length - 1;
     
-            sponsorTimes[i][0] = rows[i].startTime;
+            sponsorTimes[index][0] = rows[i].startTime;
-            sponsorTimes[i][1] = rows[i].endTime;
+            sponsorTimes[index][1] = rows[i].endTime;
+
+            votes[index] = rows[i].votes;
+            UUIDs[index] = rows[i].UUID;
         }
 
+        if (sponsorTimes.length == 0) {
+            res.sendStatus(404);
+            return;
+        }
+
+        organisedData = getVoteOrganisedSponsorTimes(sponsorTimes, votes, UUIDs);
+        sponsorTimes = organisedData.sponsorTimes;
+        UUIDs = organisedData.UUIDs;
+
         if (sponsorTimes.length == 0) {
             res.sendStatus(404);
         } else {
             //send result
             res.send({
-                sponsorTimes: sponsorTimes
+                sponsorTimes: sponsorTimes,
+                UUIDs: UUIDs
             })
         }
     });
@@ -106,6 +128,230 @@ app.get('/api/postVideoSponsorTimes', function (req, res) {
     });
 });
 
+//voting endpoint
+app.get('/api/voteOnSponsorTime', function (req, res) {
+    let UUID = req.query.UUID;
+    let userID = req.query.userID;
+    let type = req.query.type;
+
+    if (UUID == undefined || userID == undefined || type == undefined) {
+        //invalid request
+        res.sendStatus(400);
+        return;
+    }
+
+    //-1 for downvote, 1 for upvote. Maybe more depending on reputation in the future
+    let incrementAmount = 0;
+
+    //don't use userID for now, and just add the vote
+    if (type == 1) {
+        //upvote
+        incrementAmount = 1;
+    } else if (type == 0) {
+        //downvote
+        incrementAmount = -1;
+    } else {
+        //unrecongnised type of vote
+        req.sendStatus(400);
+        return;
+    }
+
+    db.prepare("UPDATE sponsorTimes SET votes = votes + ? WHERE UUID = ?").run(incrementAmount, UUID);
+
+    //added to db
+    res.sendStatus(200);
+});
+
 app.get('/database.db', function (req, res) {
     res.sendFile("./databases/sponsorTimes.db", { root: __dirname });
-});
+});
+
+
+//This function will find sponsor times that are contained inside of eachother, called similar sponsor times
+//Only one similar time will be returned, randomly generated based on the sqrt of votes.
+//This allows new less voted items to still sometimes appear to give them a chance at getting votes.
+//Sponsor times with less than -2 votes are already ignored before this function is called
+function getVoteOrganisedSponsorTimes(sponsorTimes, votes, UUIDs) {
+    //list of sponsors that are contained inside eachother
+    let similarSponsors = [];
+
+    for (let i = 0; i < sponsorTimes.length; i++) {
+        //see if the start time is located between the start and end time of the other sponsor time.
+        for (let j = 0; j < sponsorTimes.length; j++) {
+            if (sponsorTimes[j][0] > sponsorTimes[i][0] && sponsorTimes[j][0] < sponsorTimes[i][1]) {
+                //sponsor j is contained in sponsor i
+                similarSponsors.push([i, j]);
+            }
+        }
+    }
+
+    let similarSponsorsGroups = [];
+    //once they have been added to a group, they don't need to be dealt with anymore
+    let dealtWithSimilarSponsors = [];
+
+    //create lists of all the similar groups (if 1 and 2 are similar, and 2 and 3 are similar, the group is 1, 2, 3)
+    for (let i = 0; i < similarSponsors.length; i++) {
+        if (dealtWithSimilarSponsors.includes(i)) {
+            //dealt with already
+            continue;
+        }
+
+        //this is the group of indexes that are similar
+        let group = similarSponsors[i];
+        for (let j = 0; j < similarSponsors.length; j++) {
+            if (group.includes(similarSponsors[j][0]) || group.includes(similarSponsors[j][1])) {
+                //this is a similar group
+                group.push(similarSponsors[j][0]);
+                group.push(similarSponsors[j][1]);
+                dealtWithSimilarSponsors.push(j);
+            }
+        }
+        similarSponsorsGroups.push(group);
+    }
+
+    //remove duplicate indexes in group arrays
+    for (let i = 0; i < similarSponsorsGroups.length; i++) {
+        uniqueArray = similarSponsorsGroups[i].filter(function(item, pos, self) {
+            return self.indexOf(item) == pos;
+        });
+
+        similarSponsorsGroups[i] = uniqueArray;
+    }
+
+    let weightedRandomIndexes = getWeightedRandomChoiceForArray(similarSponsorsGroups, votes);
+
+    let finalSponsorTimeIndexes = weightedRandomIndexes.finalChoices;
+    //the sponsor times either chosen to be added to finalSponsorTimeIndexes or chosen not to be added
+    let finalSponsorTimeIndexesDealtWith = weightedRandomIndexes.choicesDealtWith;
+
+    let voteSums = weightedRandomIndexes.weightSums;
+    //convert these into the votes
+    for (let i = 0; i < voteSums.length; i++) {
+        if (voteSums[i] != undefined) {
+            //it should use the sum of votes, since anyone upvoting a similar sponsor is upvoting the existence of that sponsor.
+            votes[finalSponsorTimeIndexes[i]] = voteSums;
+        }
+    }
+
+    //find the indexes never dealt with and add them
+    for (let i = 0; i < sponsorTimes.length; i++) {
+        if (!finalSponsorTimeIndexesDealtWith.includes(i)) {
+            finalSponsorTimeIndexes.push(i)
+        }
+    }
+
+    //if there are too many indexes, find the best 4
+    finalSponsorTimeIndexes = getWeightedRandomChoice(finalSponsorTimeIndexes, votes, 4).finalChoices;
+
+    //convert this to a final array to return
+    let finalSponsorTimes = [];
+    for (let i = 0; i < finalSponsorTimeIndexes.length; i++) {
+        finalSponsorTimes.push(sponsorTimes[finalSponsorTimeIndexes[i]]);
+    }
+
+    //convert this to a final array of UUIDs as well
+    let finalUUIDs = [];
+    for (let i = 0; i < finalSponsorTimeIndexes.length; i++) {
+        finalUUIDs.push(UUIDs[finalSponsorTimeIndexes[i]]);
+    }
+
+    return {
+        sponsorTimes: finalSponsorTimes,
+        UUIDs: finalUUIDs
+    };
+}
+
+//gets the getWeightedRandomChoice for each group in an array of groups
+function getWeightedRandomChoiceForArray(choiceGroups, weights) {
+    let finalChoices = [];
+    //the indexes either chosen to be added to final indexes or chosen not to be added
+    let choicesDealtWith = [];
+    //for each choice group, what are the sums of the weights
+    let weightSums = [];
+
+    for (let i = 0; i < choiceGroups.length; i++) {
+        //find weight sums for this group
+        weightSums.push(0);
+        for (let j = 0; j < choiceGroups[i].length; j++) {
+            //only if it is a positive vote, otherwise it is probably just a sponsor time with slightly wrong time
+            if (weights[choiceGroups[i][j]] > 0) {
+                weightSums[weightSums.length - 1] += weights[choiceGroups[i][j]];
+            }
+        }
+
+        //create a random choice for this group
+        let randomChoice = getWeightedRandomChoice(choiceGroups[i], weights, 1)
+        finalChoices.push(randomChoice.finalChoices);
+
+        for (let j = 0; j < randomChoice.choicesDealtWith.length; j++) {
+            choicesDealtWith.push(randomChoice.choicesDealtWith[j])
+        }
+    }
+
+    return {
+        finalChoices: finalChoices,
+        choicesDealtWith: choicesDealtWith,
+        weightSums: weightSums
+    };
+}
+
+//gets a weighted random choice from the indexes array based on the weights.
+//amountOfChoices speicifies the amount of choices to return, 1 or more.
+//choices are unique
+function getWeightedRandomChoice(choices, weights, amountOfChoices) {
+    if (amountOfChoices > choices.length) {
+        //not possible, since all choices must be unique
+        return null;
+    }
+
+    let finalChoices = [];
+    let choicesDealtWith = [];
+
+    let sqrtWeightsList = [];
+    //the total of all the weights run through the cutom sqrt function
+    let totalSqrtWeights = 0;
+    for (let j = 0; j < choices.length; j++) {
+        //multiplying by 10 makes around 13 votes the point where it the votes start not mattering as much (10 + 3)
+        //The 3 makes -2 the minimum votes before being ignored completely
+        //https://www.desmos.com/calculator/ljftxolg9j
+        //this can be changed if this system increases in popularity.
+        let sqrtVote = Math.sqrt((weights[choices[j]] + 3) * 10);
+        sqrtWeightsList.push(sqrtVote)
+        totalSqrtWeights += sqrtVote;
+
+        //this index has now been deat with
+        choicesDealtWith.push(choices[j]);
+    }
+
+    //iterate and find amountOfChoices choices
+    let randomNumber = Math.random();
+    //this array will keep adding to this variable each time one sqrt vote has been dealt with
+    //this is the sum of all the sqrtVotes under this index
+    let currentVoteNumber = 0;
+    for (let j = 0; j < sqrtWeightsList.length; j++) {
+        if (randomNumber > currentVoteNumber / totalSqrtWeights && randomNumber < (currentVoteNumber + sqrtWeightsList[j]) / totalSqrtWeights) {
+            //this one was randomly generated
+            finalChoices.push(choices[j]);
+            //remove that from original array, for next recursion pass if it happens
+            choices.splice(j, 1);
+            break;
+        }
+
+        //add on to the count
+        currentVoteNumber += sqrtWeightsList[j];
+    }
+    
+    //add on the other choices as well using recursion
+    if (amountOfChoices > 1) {
+        let otherChoices = getWeightedRandomChoice(choices, weights, amountOfChoices - 1).finalChoices;
+        //add all these choices to the finalChoices array being returned
+        for (let i = 0; i < otherChoices.length; i++) {
+            finalChoices.push(otherChoices[i]);
+        }
+    }
+
+    return {
+        finalChoices: finalChoices,
+        choicesDealtWith: choicesDealtWith
+    };
+}