Merge pull request #68 from apollostack/hot

Sashko Stubailo · web-flow · commit 0b101c4de03e · 2016-10-25T17:37:30.000-04:00
Implement Hot ranking
diff --git a/api/sql/models.js b/api/sql/models.js
@@ -1,3 +1,5 @@
+import RedditScore from 'reddit-score';
+
 import knex from './connector';
 
 // A utility function that makes sure we always query the same columns
@@ -66,6 +68,8 @@ export class Entries {
       query.orderBy('created_at', 'desc');
     } else if (type === 'TOP') {
       query.orderBy('score', 'desc');
+    } else if (type === 'HOT') {
+      query.orderBy('hot_score', 'desc');
     } else {
       throw new Error(`Feed type ${type} not implemented.`);
     }
@@ -96,7 +100,7 @@ export class Entries {
 
     return Promise.resolve()
 
-    // First, get the entry_id from repoFullName
+      // First, get the entry_id from repoFullName
       .then(() => (
         knex('entries')
           .where({
@@ -125,6 +129,57 @@ export class Entries {
             username,
             vote_value: voteValue,
           })
+      ))
+      // Update hot score
+      .then(() => this.updateHotScore(repoFullName));
+  }
+
+  updateHotScore(repoFullName) {
+    let entryId;
+    let createdAt;
+
+    return Promise.resolve()
+      .then(() => (
+        knex('entries')
+          .where({
+            repository_name: repoFullName,
+          })
+          .select(['id', 'created_at'])
+          .first()
+          .then(({ id, created_at }) => {
+            entryId = id;
+            createdAt = created_at;
+          })
+      ))
+      .then(() => {
+        return knex('votes')
+          .select(['vote_value'])
+          .where({
+            entry_id: entryId,
+          });
+      })
+      .then((results) => {
+        function countVotes(vote) {
+          return (count, value) => count + (value === vote ? 1 : 0);
+        }
+
+        if (results && results.map) {
+          const votes = results.map(vote => vote.vote_value);
+          const ups = votes.reduce(countVotes(1), 0);
+          const downs = votes.reduce(countVotes(-1), 0);
+          const date = createdAt instanceof Date ? createdAt : new Date(createdAt);
+
+          return (new RedditScore()).hot(ups, downs, date);
+        }
+
+        return 0;
+      })
+      .then(hotScore => (
+        knex('entries')
+          .where('id', entryId)
+          .update({
+            hot_score: hotScore,
+          })
       ));
   }
 
@@ -183,6 +238,7 @@ export class Entries {
               posted_by: username,
             });
         }
-      }));
+      }))
+      .then(() => this.updateHotScore(repoFullName));
   }
 }
diff --git a/api/sql/schema.js b/api/sql/schema.js
@@ -39,6 +39,9 @@ type Entry {
   # The score of this repository, upvotes - downvotes
   score: Int!
 
+  # The hot score of this repository
+  hotScore: Int!
+
   # Comments posted about this repository
   comments: [Comment]! # Should this be paginated?
 
@@ -66,6 +69,7 @@ export const resolvers = {
       return context.Comments.getCommentsByRepoName(repository_name);
     },
     createdAt: property('created_at'),
+    hotScore: property('hot_score'),
     commentCount({ repository_name }, _, context) {
       return context.Comments.getCommentCount(repository_name) || constant(0);
     },
diff --git a/migrations/20160518201950_create_comments_entries_votes.js b/migrations/20160518201950_create_comments_entries_votes.js
@@ -13,6 +13,7 @@ export function up(knex, Promise) {
       table.timestamps();
       table.string('repository_name').unique();
       table.string('posted_by');
+      table.float('hot_score');
     }),
 
     knex.schema.createTable('votes', (table) => {
diff --git a/package.json b/package.json
@@ -54,6 +54,7 @@
     "lodash": "4.16.4",
     "passport": "0.3.2",
     "passport-github": "1.1.0",
+    "reddit-score": "0.0.1",
     "request-promise": "4.1.1",
     "sqlite3": "3.1.7",
     "subscriptions-transport-ws": "0.2.6"
diff --git a/seeds/seed.js b/seeds/seed.js
@@ -1,4 +1,21 @@
 import _ from 'lodash';
+import RedditScore from 'reddit-score';
+
+function countScore(score) {
+  return (count, value) => count + (value === score ? 1 : 0);
+}
+
+function hot(repoVotes, date) {
+  const redditScore = new RedditScore();
+
+  const createdAt = date instanceof Date ? date : new Date(date);
+
+  const scores = _.values(repoVotes || {});
+  const ups = scores.reduce(countScore(1), 0);
+  const downs = scores.reduce(countScore(-1), 0);
+
+  return redditScore.hot(ups, downs, createdAt);
+}
 
 const repos = [
   {
@@ -83,11 +100,16 @@ export function seed(knex, Promise) {
   // Insert some entries for the repositories
   .then(() => {
     return Promise.all(repos.map(({ repository_name, posted_by }, i) => {
+      const createdAt = Date.now() - (i * 10000);
+      const repoVotes = votes[repository_name];
+      const hotScore = hot(repoVotes, createdAt);
+
       return knex('entries').insert({
-        created_at: Date.now() - (i * 10000),
+        created_at: createdAt,
         updated_at: Date.now() - (i * 10000),
         repository_name,
         posted_by,
+        hot_score: hotScore,
       }).then(([id]) => {
         repoIds[repository_name] = id;
       });
