1 files changed, 54 insertions, 0 deletions
diff --git a/src/command/focus.zig b/src/command/focus.zig
new file mode 100644
index 0000000..930a36c
--- /dev/null
+++ b/src/command/focus.zig
@@ -0,0 +1,54 @@
+// This file is part of river, a dynamic tiling wayland compositor.
+//
+// Copyright 2020 Isaac Freund
+//
+// 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 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 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 <https://www.gnu.org/licenses/>.
+
+const c = @import("../c.zig");
+
+const Arg = @import("../Command.zig").Arg;
+const Seat = @import("../Seat.zig");
+const View = @import("../View.zig");
+const ViewStack = @import("../view_stack.zig").ViewStack;
+
+/// Focus either the next or the previous visible view, depending on the enum
+/// passed. Does nothing if there are 1 or 0 views in the stack.
+pub fn focus(seat: *Seat, arg: Arg) void {
+    const direction = arg.direction;
+    const output = seat.focused_output;
+    if (seat.focused_view) |current_focus| {
+        // If there is a currently focused view, focus the next visible view in the stack.
+        const focused_node = @fieldParentPtr(ViewStack(View).Node, "view", current_focus);
+        var it = switch (direction) {
+            .Next => ViewStack(View).iterator(focused_node, output.current_focused_tags),
+            .Prev => ViewStack(View).reverseIterator(focused_node, output.current_focused_tags),
+        };
+
+        // Skip past the focused node
+        _ = it.next();
+        // Focus the next visible node if there is one
+        if (it.next()) |node| {
+            seat.focus(&node.view);
+            return;
+        }
+    }
+
+    // There is either no currently focused view or the last visible view in the
+    // stack is focused and we need to wrap.
+    var it = switch (direction) {
+        .Next => ViewStack(View).iterator(output.views.first, output.current_focused_tags),
+        .Prev => ViewStack(View).reverseIterator(output.views.last, output.current_focused_tags),
+    };
+    seat.focus(if (it.next()) |node| &node.view else null);
+}