Edit metadata: In the drop down list for languages, show the five most recently used languages first. Fixes #1594089 [[Enhancement] Language drop down box population](https://bugs.launchpad.net/calibre/+bug/1594089)

src/calibre/gui2/__init__.py

@@ -786,6 +786,15 @@ def decouple(prefix):
     from calibre.gui2.widgets import history
     history.decouple(prefix)
 
+_gui_prefs = gprefs
+
+def gui_prefs():
+    return _gui_prefs
+
+def set_gui_prefs(prefs):
+    global _gui_prefs
+    _gui_prefs = prefs
+
 class ResizableDialog(QDialog):
 
     # This class is present only for backwards compat with third party plugins

src/calibre/gui2/languages.py

@@ -7,6 +7,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+from calibre.gui2 import gui_prefs
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.utils.localization import lang_map
 from calibre.utils.icu import sort_key, lower
@@ -23,8 +24,10 @@ def get_lang_map():
 
 class LanguagesEdit(EditWithComplete):
 
-    def __init__(self, parent=None, db=None):
-        EditWithComplete.__init__(self, parent)
+    def __init__(self, parent=None, db=None, prefs=None):
+        self.prefs = prefs or gui_prefs()
+        self.refresh_recently_used()
+        EditWithComplete.__init__(self, parent, sort_func=self.sort_language_items_key)
 
         self.setSizeAdjustPolicy(self.AdjustToMinimumContentsLengthWithIcon)
         self.setMinimumContentsLength(20)
@@ -34,17 +37,28 @@ class LanguagesEdit(EditWithComplete):
         self.comma_rmap = {v:k for k, v in self.comma_map.iteritems()}
         self._rmap = {lower(v):k for k,v in self._lang_map.iteritems()}
         self.init_langs(db)
+        self.item_selected.connect(self.update_recently_used)
 
     def init_langs(self, db):
-        if db is not None:
-            pmap = {self._lang_map.get(x[1], x[1]):1 for x in
-                    db.get_languages_with_ids()}
-            all_items = sorted(self._lang_map.itervalues(),
-                key=lambda x: (-pmap.get(x, 0), sort_key(x)))
-        else:
-            all_items = sorted(self._lang_map.itervalues(),
-                key=lambda x: sort_key(x))
-        self.update_items_cache(all_items)
+        self.update_items_cache(self._lang_map.itervalues())
+
+    def refresh_recently_used(self):
+        recently_used = self.prefs.get('recently_used_languages') or ()
+        self.recently_used = {x:i for i, x in enumerate(recently_used) if x}
+
+    def update_recently_used(self):
+        recently_used = self.prefs.get('recently_used_languages') or []
+        vals = self.vals
+        for x in vals:
+            if x:
+                if x in recently_used:
+                    recently_used.remove(x)
+                recently_used.insert(0, x)
+        self.prefs.set('recently_used_languages', recently_used[:5])
+
+    def sort_language_items_key(self, val):
+        idx = self.recently_used.get(val, 100000)
+        return (idx, sort_key(val))
 
     @property
     def vals(self):

src/calibre/gui2/library/delegates.py

@@ -391,6 +391,7 @@ class LanguagesDelegate(QStyledItemDelegate, UpdateEditorGeometry):  # {{{
 
     def setModelData(self, editor, model, index):
         val = ','.join(editor.lang_codes)
+        editor.update_recently_used()
         model.setData(index, (val), Qt.EditRole)
 # }}}
 

src/calibre/gui2/metadata/basic_widgets.py

@@ -1378,6 +1378,7 @@ class LanguagesEdit(LE, ToMetadataMixin):  # {{{
         cv = self.current_val
         if cv != self.original_val:
             db.set_languages(id_, cv)
+        self.update_recently_used()
 # }}}
 
 # Identifiers {{{

src/calibre/gui2/tweak_book/editor/insert_resource.py

@@ -434,8 +434,10 @@ class NewBook(Dialog):  # {{{
         self.fmt = fmt
 
     def accept(self):
-        tprefs.set('previous_new_book_authors', unicode(self.authors.text()))
-        tprefs.set('previous_new_book_lang', (self.languages.lang_codes or [get_lang()])[0])
+        with tprefs:
+            tprefs.set('previous_new_book_authors', unicode(self.authors.text()))
+            tprefs.set('previous_new_book_lang', (self.languages.lang_codes or [get_lang()])[0])
+            self.languages.update_recently_used()
         super(NewBook, self).accept()
 
     @property

src/calibre/gui2/tweak_book/main.py

@@ -11,7 +11,7 @@ import sys, os, importlib, time
 from PyQt5.Qt import QIcon
 
 from calibre.constants import islinux, iswindows
-from calibre.gui2 import Application, ORG_NAME, APP_UID, setup_gui_option_parser, decouple
+from calibre.gui2 import Application, ORG_NAME, APP_UID, setup_gui_option_parser, decouple, set_gui_prefs
 from calibre.ptempfile import reset_base_dir
 from calibre.utils.config import OptionParser
 
@@ -60,7 +60,7 @@ def _run(args, notify=None):
 
     parser = option_parser()
     opts, args = parser.parse_args(args)
-    decouple('edit-book-')
+    decouple('edit-book-'), set_gui_prefs(tprefs)
     override = 'calibre-edit-book' if islinux else None
     app = Application(args, override_program_name=override, color_prefs=tprefs)
     app.file_event_hook = EventAccumulator()

src/calibre/gui2/tweak_book/spell.py

@@ -316,6 +316,7 @@ class ManageUserDictionaries(Dialog):
         l.addRow(bb)
         if d.exec_() != d.Accepted:
             return
+        d.loc.update_recently_used()
         word = unicode(w.text())
         lang = (loc.lang_codes or [canonicalize_lang(get_lang())])[0]
         if not word: