From 55bb2b182ebf87998145743c9cee46d414bd82c9 Mon Sep 17 00:00:00 2001
From: Radek Stepan <dev@radekstepan.com>
Date: Mon, 20 Oct 2014 19:15:41 -0700
Subject: [PATCH] binary search code

---
 src/models/projects.coffee | 30 ++++++++++++++++++++++++++++--
 src/utils/search.coffee    | 23 +++++++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 src/utils/search.coffee

diff --git a/src/models/projects.coffee b/src/models/projects.coffee
index e967621..4231875 100644
--- a/src/models/projects.coffee
+++ b/src/models/projects.coffee
@@ -4,12 +4,16 @@ config   = require '../models/config.coffee'
 mediator = require '../modules/mediator.coffee'
 Model    = require '../utils/model.coffee'
 date     = require '../utils/date.coffee'
+search   = require '../utils/search.coffee'
 user     = require './user.coffee'
 
 module.exports = new Model
 
   'name': 'models/projects'
 
+  'data':
+    'sortKey': 'priority'
+
   find: (project) ->
     _.find @data.list, project
 
@@ -32,6 +36,19 @@ module.exports = new Model
   clear: ->
     @set 'list', []
 
+  # Sort an already sorted index.
+  sort: ->
+    # Get or initialize the index.
+    index = @data.index or []
+
+    for p in @data.list
+      for m in p.milestones
+        # Run a comparator here inserting into index.
+        @data.sortKey
+
+    # Save the index.
+    @set 'index', index
+
   onconstruct: ->
     mediator.on '!projects/add',    _.bind @add, @
     mediator.on '!projects/clear',  _.bind @clear, @
@@ -40,7 +57,16 @@ module.exports = new Model
     # Init the projects.
     @set 'list', lscache.get('projects') or []
 
-    # Persist projects in local storage (sans milestones).
     @observe 'list', (projects) ->
+      # Persist projects in local storage (sans milestones).
       lscache.set 'projects', _.pluckMany projects, [ 'owner', 'name' ]
-    , 'init': no
\ No newline at end of file
+      # Update the index.
+      do @sort
+    , 'init': no
+
+    # Reset our index and re-sort.
+    @observe 'sortKey', ->
+      # Use pop as Ractive is glitchy.
+      @pop 'index' while @data.index.length
+      # Run the sort again.
+      do @sort
\ No newline at end of file
diff --git a/src/utils/search.coffee b/src/utils/search.coffee
new file mode 100644
index 0000000..e897972
--- /dev/null
+++ b/src/utils/search.coffee
@@ -0,0 +1,23 @@
+# Binary search implementation with a custom comparator function.
+module.exports = (arr, item, comparator) ->
+  # Numeric comparator.
+  comparator ?= (a, b) ->
+    switch
+      when a < b then -1
+      when a > b then +1
+      else 0
+
+  minIndex = 0
+  maxIndex = arr.length - 1
+  
+  while minIndex <= maxIndex
+    index = (minIndex + maxIndex) / 2 | 0
+    existing = arr[index]
+    
+    res = comparator existing, item
+    switch
+      when result < 0 then minIndex = index + 1
+      when result > 0 then maxIndex = index - 1
+      else return index
+
+  -1
\ No newline at end of file