Update welcome model to list a few languages

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>

subiquity/controllers/welcome.py

@@ -15,6 +15,7 @@
 
 from subiquity.controllers import BaseController
 from subiquity.views.welcome import WelcomeView
+from subiquity.models.welcome import WelcomeModel
 
 
 class WelcomeController(BaseController):
@@ -22,7 +23,8 @@ class WelcomeController(BaseController):
     controller_name = "Welcome to Ubuntu"
 
     def show(self):
-        return WelcomeView(self.finish)
+        model = WelcomeModel()
+        return WelcomeView(model, self.finish)
 
     def finish(self, code, val):
         raise SystemExit("Saw res: {}, val: {}".format(code, val))

subiquity/models/welcome.py

@@ -15,7 +15,7 @@
 
 """ Welcome Model
 
-Welcome model provides user with installation options
+Welcome model provides user with language selection
 
 """
 
@@ -23,7 +23,8 @@ from subiquity import models
 
 
 class WelcomeModel(models.Model):
-    """ Model representing installation type
+    """ Model representing language selection
     """
 
-    install_type = None
+    supported_languages = ['English', 'Belgian', 'German', 'Italian']
+    selected_language = None

subiquity/ui/lists.py

@@ -0,0 +1,109 @@
+# Copyright 2015 Canonical, Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from urwid import ListBox, SimpleListWalker, WidgetWrap
+
+
+class Scrollable:
+
+    """A interface that makes widgets *scrollable*."""
+
+    def scroll_up(self):
+        raise NotImplementedError
+
+    def scroll_down(self):
+        raise NotImplementedError
+
+    def scroll_top(self):
+        raise NotImplementedError
+
+    def scroll_bottom(self):
+        raise NotImplementedError
+
+
+class ScrollableListBox(ListBox, Scrollable):
+
+    """
+    A ``urwid.ListBox`` subclass that implements the
+    :class:`~subiquity.ui.Scrollable` interface.
+    """
+
+    def __init__(self,
+                 contents,
+                 offset=1):
+        """
+        Arguments:
+        `contents` is a list with the elements contained in the
+        `ScrollableListBox`.
+        `offset` is the number of position that `scroll_up` and `scroll_down`
+        shift the cursor.
+        """
+        self.offset = offset
+
+        ListBox.__init__(self,
+                         SimpleListWalker(contents))
+
+    def scroll_up(self):
+        focus_status, pos = self.get_focus()
+        if pos is None:
+            return
+
+        new_pos = pos - self.offset
+        if new_pos < 0:
+            new_pos = 0
+        self.set_focus(new_pos)
+
+    def scroll_down(self):
+        focus_status, pos = self.get_focus()
+        if pos is None:
+            return
+
+        new_pos = pos + self.offset
+        if new_pos >= len(self.body):
+            new_pos = len(self.body) - 1
+        self.set_focus(new_pos)
+
+    def scroll_top(self):
+        if len(self.body):
+            self.set_focus(0)
+
+    def scroll_bottom(self):
+        last = len(self.body) - 1
+        if last:
+            self.set_focus(last)
+
+
+class ScrollableWidgetWrap(WidgetWrap, Scrollable):
+
+    """
+    A ``urwid.WidgetWrap`` for :class:`~subiquity.ui.Scrollable`, list-like
+    widgets.
+    """
+
+    def __init__(self, contents=None):
+        columns = [] if contents is None else contents
+        WidgetWrap.__init__(self, columns)
+
+    def scroll_up(self):
+        self._w.scroll_up()
+
+    def scroll_down(self):
+        self._w.scroll_down()
+
+    def scroll_top(self):
+        self._w.scroll_top()
+
+    def scroll_bottom(self):
+        self._w.scroll_bottom()