events: introduce AercMsg and QueueRedraw

Add AercMsg as a main interface for internal communication in aerc in
preparation for a main event loop. Add a QueueRedraw function to to
trigger a redraw. This will be needed for widgets which should be drawn
after some delay (completions, terminal, for example)

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/ui/ui.go b/lib/ui/ui.go
index 632d5f1d..d477242e 100644
--- a/lib/ui/ui.go
+++ b/lib/ui/ui.go
@@ -7,6 +7,14 @@ import (
 	"github.com/gdamore/tcell/v2"
 )
 
+var MsgChannel = make(chan AercMsg, 50)
+
+// QueueRedraw sends a nil message into the MsgChannel. Nothing will handle this
+// message, but a redraw will occur if the UI is marked as invalid
+func QueueRedraw() {
+	MsgChannel <- nil
+}
+
 type UI struct {
 	Content DrawableInteractive
 	exit    atomic.Value // bool