From 5244702e48a862ce02af7e8868444acef4da3cee Mon Sep 17 00:00:00 2001
From: Matteo Pagliazzi <matteopagliazzi@gmail.com>
Date: Mon, 11 Jan 2016 18:29:39 +0100
Subject: [PATCH] perf improvements for challenges history and migration

---
 ...enges_condense_same_day_history_entries.js | 106 ++++++++++++++++++
 website/src/controllers/api-v2/user.js        |   9 +-
 2 files changed, 111 insertions(+), 4 deletions(-)
 create mode 100644 migrations/20160111_challenges_condense_same_day_history_entries.js

diff --git a/migrations/20160111_challenges_condense_same_day_history_entries.js b/migrations/20160111_challenges_condense_same_day_history_entries.js
new file mode 100644
index 0000000000..de5f719020
--- /dev/null
+++ b/migrations/20160111_challenges_condense_same_day_history_entries.js
@@ -0,0 +1,106 @@
+var migrationName = '20160111_challenges_condense_same_day_history_entries.js';
+
+/*
+ * Compress challenges tasks history entries so that only one entry per day is kept
+ */
+
+var dbserver = '';
+var dbname = '';
+
+var mongo = require('mongoskin');
+var _ = require('lodash');
+var moment = require('moment');
+
+var dbChallenges = mongo.db(dbserver + '/' + dbname + '?auto_reconnect').collection('challenges');
+
+// Find all challenges
+var query = {
+};
+
+// we only want habits and dailies (rewards and todos don't have history)
+var fields = {
+  'habits': 1,
+  'dailys': 1,
+};
+
+function compressEntries (history) {
+  return _.chain(history)
+    .filter(function(entry) {
+      return !!entry;
+    })
+    .groupBy(function(entry) { // group by day
+      return moment(entry.date).format('YYYYMMDD');
+    })
+    .sortBy(function(entry, key) { // sort by date and transform back to array of array of entries
+      return key;
+    })
+    .map(function(entries) { // aggregate the value
+      return {
+        date: Number(entries[0].date),
+        value: _.reduce(entries, function (previousValue, entry) {
+          return previousValue + entry.value;
+        }, 0) / entries.length,
+      };
+    })
+    .value();
+};
+
+console.warn('Updating challenges...');
+var progressCount = 100;
+var count = 0;
+
+dbChallenges.findEach(query, fields, {batchSize: 250}, function(err, challenge) {
+  if (err) { return exiting(1, 'ERROR! ' + err); }
+  if (!challenge) {
+    console.warn('All appropriate challenges found.');
+    return displayData();
+  }
+  count++;
+
+  // specify challenge data to change:
+  var set = {};
+
+  if (challenge.habits && challenge.habits.length > 0) {
+    challenge.habits.forEach(function(habit, index) {
+      if (habit.history && habit.history.length > 1) {
+        var originalL = habit.history.length;
+        habit.history = compressEntries(habit.history);
+        if (originalL > 1000) console.log(originalL, habit.history.length);
+        set['habits.' + index + '.history'] = habit.history;
+      }
+    });
+  }
+
+  if (challenge.dailys && challenge.dailys.length > 0) {
+    challenge.dailys.forEach(function(daily, index) {
+      if (daily.history && daily.history.length > 1) {
+        var originalL = daily.history.length;
+        daily.history = compressEntries(daily.history);
+        if (originalL > 1000) console.log(originalL, daily.history.length);
+        set['dailys.' + index + '.history'] = daily.history;
+      }
+    });
+  }
+
+  dbChallenges.update({_id: challenge._id}, {$set: set}, function(err) {
+    if(err) throw err;
+    console.log('updated a challenge');
+  });
+  if (count%progressCount == 0) console.warn(count + ' ' + challenge._id);
+});
+
+function displayData() {
+  console.warn('\n' + count + ' challenges processed\n');
+  return exiting(0);
+}
+
+
+function exiting(code, msg) {
+  code = code || 0; // 0 = success
+  if (code && !msg) { msg = 'ERROR!'; }
+  if (msg) {
+    if (code) { console.error(msg); }
+    else      { console.log(  msg); }
+  }
+  process.exit(code);
+}
diff --git a/website/src/controllers/api-v2/user.js b/website/src/controllers/api-v2/user.js
index e0dab67ded..7d6bfa1681 100644
--- a/website/src/controllers/api-v2/user.js
+++ b/website/src/controllers/api-v2/user.js
@@ -150,11 +150,12 @@ api.score = function(req, res, next) {
             date: +(new Date),
             value: t.value
           });
-        }
 
-        if (t.history.length > 365) {
-          t.history = shared.preenHistory(t.history, true); // true means the challenge will retain as much entries as a subscribed user
-          chal.markModified(`${t.type}s.${tIndex}.history`); // Setting habits/dailys as modified because we don't know the index of the task
+          // Only preen task history once a day when the task is scored first
+          if (t.history.length > 365) {
+            t.history = shared.preenHistory(t.history, true); // true means the challenge will retain as much entries as a subscribed user
+            chal.markModified(`${t.type}s.${tIndex}.history`); // Setting habits/dailys as modified because we don't know the index of the task
+          }
         }
       }
       chal.save();