Window: Implement the UI as an FSM.

This way it's clear what parts of the UI should be active when
selecting, editing, ...

It also allows us to get rid of a hard to follow combo of
edit_mode/selection_mode/new_contact variables.

1 files changed, 60 insertions, 0 deletions

diff --git a/src/contacts-ui-state.vala b/src/contacts-ui-state.vala
new file mode 100644
index 0000000..ad7230b
--- /dev/null
+++ b/src/contacts-ui-state.vala
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2018 Niels De Graef <nielsdegraef@gmail.com>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Roughly put, the behaviour of the UI of Contacts can be divided in several
+ * categories. We represent this with the UiState enum, which can be shared
+ * (and sync-ed) between the different parts of the app.
+ *
+ * Note that there is one exception to this: the initial setup is handled
+ * completely separately in the {@link SetupWindow}.
+ */
+public enum Contacts.UiState {
+  /**
+   * The start state: no contact is selected/displayed.
+   */
+  NORMAL,
+
+  /**
+   * A contact has been selected and is displayed.
+   */
+  SHOWING,
+
+  /**
+   * Zero or more contacts are selected (but this can be changed).
+   * No contact should be displayed.
+   */
+  SELECTING,
+
+  /**
+   * The selected contact is being edited.
+   */
+  UPDATING,
+
+  /**
+   * A new contact is being created.
+   */
+  CREATING;
+
+  /**
+   * Returns whether we're editing a contact, either by changing an existing
+   * one, or by creating a new one.
+   */
+  public bool editing () {
+    return this == UiState.UPDATING || this == UiState.CREATING;
+  }
+}