Big i18n tools update, I/II.

Notes:
* Everything is still a bit raw and sometimes hackish.
* Not every feature implemented yet.
* A bunch of cleanup is still needed.
* Doc needs to be updated too!

release/scripts/modules/bl_i18n_utils/languages_menu_utils.py

@@ -0,0 +1,96 @@
+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ***** END GPL LICENSE BLOCK *****
+
+# <pep8 compliant>
+
+# Update "languages" text file used by Blender at runtime to build translations menu.
+
+
+import os
+
+
+OK = 0
+MISSING = 1
+TOOLOW = 2
+FORBIDDEN = 3
+FLAG_MESSAGES = {
+    OK: "",
+    MISSING: "No translation yet!",
+    TOOLOW: "Not enough advanced to be included...",
+    FORBIDDEN: "Explicitly forbidden!",
+}
+
+def gen_menu_file(stats, settings):
+    # Generate languages file used by Blender's i18n system.
+    # First, match all entries in LANGUAGES to a lang in stats, if possible!
+    tmp = []
+    for uid_num, label, uid, in settings.LANGUAGES:
+        if uid in stats:
+            if uid in settings.IMPORT_LANGUAGES_SKIP:
+                tmp.append((stats[uid], uid_num, label, uid, FORBIDDEN))
+            else:
+                tmp.append((stats[uid], uid_num, label, uid, OK))
+        else:
+            tmp.append((0.0, uid_num, label, uid, MISSING))
+    stats = tmp
+    limits = sorted(settings.LANGUAGES_CATEGORIES, key=lambda it: it[0], reverse=True)
+    idx = 0
+    stats = sorted(stats, key=lambda it: it[0], reverse=True)
+    langs_cats = [[] for i in range(len(limits))]
+    highest_uid = 0
+    for lvl, uid_num, label, uid, flag in stats:
+        if lvl < limits[idx][0]:
+            # Sub-sort languages by iso-codes.
+            langs_cats[idx].sort(key=lambda it: it[2])
+            idx += 1
+        if lvl < settings.IMPORT_MIN_LEVEL and flag == OK:
+            flag = TOOLOW
+        langs_cats[idx].append((uid_num, label, uid, flag))
+        if abs(uid_num) > highest_uid:
+            highest_uid = abs(uid_num)
+    # Sub-sort last group of languages by iso-codes!
+    langs_cats[idx].sort(key=lambda it: it[2])
+    data_lines = [
+        "# File used by Blender to know which languages (translations) are available, ",
+        "# and to generate translation menu.",
+        "#",
+        "# File format:",
+        "# ID:MENULABEL:ISOCODE",
+        "# ID must be unique, except for 0 value (marks categories for menu).",
+        "# Line starting with a # are comments!",
+        "#",
+        "# Automatically generated by bl_i18n_utils/update_languages_menu.py script.",
+        "# Highest ID currently in use: {}".format(highest_uid),
+    ]
+    for cat, langs_cat in zip(limits, langs_cats):
+        data_lines.append("#")
+        # Write "category menu label"...
+        if langs_cat:
+            data_lines.append("0:{}:".format(cat[1]))
+        else:
+            # Do not write the category if it has no language!
+            data_lines.append("# Void category! #0:{}:".format(cat[1]))
+        # ...and all matching language entries!
+        for uid_num, label, uid, flag in langs_cat:
+            if flag == OK:
+                data_lines.append("{}:{}:{}".format(uid_num, label, uid))
+            else:
+                # Non-existing, commented entry!
+                data_lines.append("# {} #{}:{}:{}".format(FLAG_MESSAGES[flag], uid_num, label, uid))
+    with open(os.path.join(settings.TRUNK_MO_DIR, settings.LANGUAGES_FILE), 'w') as f:
+        f.write("\n".join(data_lines))