Revert "Revert "Fetch boards.json data.""

This reverts commit cc03357e071dc33bc54d4e25870998bde2d34139.

src/General/BoardsJSON.coffee

@@ -0,0 +1,32 @@
+BoardsJSON =
+  cbs: []
+
+  init: ->
+    if (Conf['boardsJSON'].lastChecked or 0) < Date.now() - 2 * $.HOUR
+      $.ajax '//a.4cdn.org/boards.json', onloadend: @load
+    else
+      @set Conf['boardsJSON'].boards
+
+  load: ->
+    if @status is 200
+      boards = {}
+      for board in @response.boards
+        boards[board.board] = board
+      $.set 'boardsJSON', {boards, lastChecked: Date.now()}
+    else
+      {boards} = Conf['boardsJSON']
+      new Notice 'warning', "Failed to load boards JSON. Error #{@statusText} (#{@status})", 20
+    BoardsJSON.set boards
+
+  set: (@boards) ->
+    for ID, board of @boards
+      g.boards[ID]?.json = board
+    for cb in @cbs
+      $.queueTask cb
+    return
+
+  ready: (cb) ->
+    if @boards
+      cb()
+    else
+      @cbs.push cb

src/classes/Board.coffee

@@ -4,5 +4,6 @@ class Board
   constructor: (@ID) ->
     @threads = new SimpleDict()
     @posts   = new SimpleDict()
+    @json    = BoardsJSON.boards?[@ID]
 
     g.boards[@] = @

src/main/Main.coffee

@@ -43,6 +43,7 @@ Main =
 
     for db in DataBoard.keys
       Conf[db] = boards: {}
+    Conf['boardsJSON'] = boards: {}
     Conf['archives'] = Redirect.archives
     Conf['selectedArchives'] = {}
     Conf['cooldowns'] = {}
@@ -430,6 +431,7 @@ Main =
 
   features: [
     ['Polyfill',                  Polyfill]
+    ['Boards JSON',               BoardsJSON]
     ['Normalize URL',             NormalizeURL]
     ['Captcha Configuration',     Captcha.replace]
     ['Redirect',                  Redirect]