[grilo-plugins] Revert "lua-factory: port grl-spotify-cover.lua to the new lua system"

[Bastien Nocera <hadess src gnome org>]

commit cee1083cbbb1f98a3156e6c0a410148296e0177e
Author: Victor Toso <me victortoso com>
Date:   Tue Mar 8 23:28:09 2016 +0100

    Revert "lua-factory: port grl-spotify-cover.lua to the new lua system"
    
    This reverts commit 9b329f3e5246477f039a1fb2b129706370237c89.
    
    But keeps grl.fetch callback as function instead of string
    
    https://bugzilla.gnome.org/show_bug.cgi?id=763046

 src/lua-factory/sources/grl-spotify-cover.lua |   31 +++++++++++++------------
 1 files changed, 16 insertions(+), 15 deletions(-)
---
diff --git a/src/lua-factory/sources/grl-spotify-cover.lua b/src/lua-factory/sources/grl-spotify-cover.lua
index 638ca37..d04ffe3 100644
--- a/src/lua-factory/sources/grl-spotify-cover.lua
+++ b/src/lua-factory/sources/grl-spotify-cover.lua
@@ -47,34 +47,34 @@ SPOTIFY_SEARCH_ALBUM = 'https://api.spotify.com/v1/search?q=album:%s+artist:%s&t
 -- Handlers of Grilo functions --
 ---------------------------------
 
-function grl_source_resolve(media, options, callback)
-  local url
+function grl_source_resolve()
+  local url, req
   local artist, title
 
-  if not media or not media.artist or not media.album
-    or #media.artist == 0 or #media.album == 0 then
-    callback()
+  req = grl.get_media_keys()
+  if not req or not req.artist or not req.album
+    or #req.artist == 0 or #req.album == 0 then
+    grl.callback()
     return
   end
 
   -- Prepare artist and title strings to the url
-  artist = grl.encode(media.artist)
-  album = grl.encode(media.album)
+  artist = grl.encode(req.artist)
+  album = grl.encode(req.album)
   url = string.format(SPOTIFY_SEARCH_ALBUM, album, artist)
 
-  local userdata = {callback = callback, media = media}
-  grl.fetch(url, fetch_page_cb, userdata)
+  grl.fetch(url, fetch_page_cb)
 end
 
 ---------------
 -- Utilities --
 ---------------
 
-function fetch_page_cb(result, userdata)
+function fetch_page_cb(result)
   local json = {}
 
   if not result then
-    userdata.callback()
+    grl.callback()
     return
   end
 
@@ -85,14 +85,15 @@ function fetch_page_cb(result, userdata)
      not json.albums.items or
      not #json.albums.items or
      not json.albums.items[1].images then
-    userdata.callback()
+    grl.callback()
     return
   end
 
-  userdata.media.thumbnail = {}
+  local media = {}
+  media.thumbnail = {}
   for i, item in ipairs(json.albums.items[1].images) do
-    table.insert(userdata.media.thumbnail, item.url)
+    table.insert(media.thumbnail, item.url)
   end
 
-  userdata.callback(userdata.media, 0)
+  grl.callback(media, 0)
 end