Add event leaderboard endpoint

src/routes/events/index.js

@@ -7,13 +7,15 @@ const deleteEvent = require('./delete-event');
 const editEvent = require('./edit-event');
 const getEvent = require('./get-event');
 const leaveEvent = require('./leave-event');
+const listEventLeaderboard = require('./list-event-leaderboard');
 const listEvents = require('./list-events');
 const joinEvent = require('./join-event');
 
 const router = new express.Router();
 
 router.get('', listEvents);
 router.post('', isAuthenticated({ isOptional: false }), createEvent);
+router.get('/:eventId/leaderboard', listEventLeaderboard);
 router.get('/:eventId', getEvent);
 router.put('/:eventId', isAuthenticated({ isOptional: false }), editEvent);
 router.delete('/:eventId', isAuthenticated({ isOptional: false }), deleteEvent);

src/routes/events/list-event-leaderboard.js

@@ -0,0 +1,135 @@
+const mongoose = require('mongoose');
+const { isInt, isMongoId } = require('validator');
+
+const { Event } = require('../../models/event');
+const { Review } = require('../../models/review');
+
+const MAX_LEADERBOARD_USERS = 5;
+
+module.exports = async (req, res, next) => {
+  const errors = {};
+  const queryParams = req.query;
+  let eventId = req.params.eventId;
+
+  if (!isMongoId(eventId)) {
+    return res.status(400).json({ general: 'Event not found' });
+  }
+
+  if (queryParams.limit && !isInt(queryParams.limit)) {
+    errors.limit = 'Should be a integer';
+  } else if (parseInt(queryParams.limit, 10) < 1) {
+    errors.limit = 'Should be greater than or equal to 1';
+  } else if (parseInt(queryParams.limit, 10) > MAX_LEADERBOARD_USERS) {
+    errors.limit = `Should be less than or equal to ${MAX_LEADERBOARD_USERS}`;
+  }
+
+  if (Object.keys(errors).length) return res.status(400).json(errors);
+
+  eventId = mongoose.Types.ObjectId(eventId);
+
+  let event;
+  try {
+    event = await Event.findOne({ _id: eventId, isArchived: false })
+      .select('_id')
+      .lean();
+  } catch (err) {
+    console.log(
+      `Event ${eventId} failed to be found at list-event-leaderboard`
+    );
+    return next(err);
+  }
+
+  if (!event) {
+    return res.status(404).json({ general: 'Event not found' });
+  }
+
+  const pageLimit = queryParams.limit
+    ? parseInt(queryParams.limit, 10)
+    : MAX_LEADERBOARD_USERS;
+
+  let users;
+  let total;
+  try {
+    const leaderboardPipeline = [
+      {
+        $match: {
+          event: eventId
+        }
+      },
+      {
+        $group: {
+          _id: '$user',
+          reviewsAmount: { $sum: 1 }
+        }
+      },
+      {
+        $lookup: {
+          from: 'users',
+          localField: '_id',
+          foreignField: '_id',
+          as: 'user'
+        }
+      },
+      {
+        $unwind: '$user'
+      },
+      {
+        $match: {
+          'user.isAdmin': false,
+          'user.isArchived': false,
+          'user.isBlocked': false
+        }
+      },
+      {
+        $sort: { reviewsAmount: -1, 'user.createdAt': 1 }
+      }
+    ];
+    const totalResults = await Review.aggregate([
+      ...leaderboardPipeline,
+      {
+        $count: 'total'
+      }
+    ]);
+
+    users = await Review.aggregate([
+      ...leaderboardPipeline,
+      {
+        $limit: pageLimit
+      },
+      {
+        $project: {
+          _id: 0,
+          id: '$user._id',
+          avatar: '$user.avatar',
+          firstName: '$user.firstName',
+          lastName: '$user.lastName',
+          reviewsAmount: 1,
+          username: '$user.username'
+        }
+      }
+    ]);
+
+    total = totalResults.length ? totalResults[0].total : 0;
+  } catch (err) {
+    console.log('Event leaderboard users failed to be found or count');
+    return next(err);
+  }
+
+  const results = users.map((user, index) => ({
+    id: user.id,
+    avatar: user.avatar,
+    firstName: user.firstName,
+    lastName: user.lastName,
+    username: user.username,
+    reviewsAmount: user.reviewsAmount,
+    ranking: index + 1
+  }));
+
+  return res.status(200).json({
+    page: results.length ? 1 : null,
+    lastPage: results.length ? 1 : null,
+    pageLimit,
+    total,
+    results
+  });
+};