send: move code to lib for reuse

Move the code which handles the preparation of a sender into which the
message can be written into lib to allow for reuse. Also hide the
sending backend a bit more from the `:send` command code by introducing
a NewSender function which determines which backend should be used and
invokes the appropriate sender factory function.

Rename send() to sendHelper() to avoid collision.

Signed-off-by: Karel Balej <balejk@matfyz.cz>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/send/jmap.go b/lib/send/jmap.go
new file mode 100644
index 00000000..9682629e
--- /dev/null
+++ b/lib/send/jmap.go
@@ -0,0 +1,40 @@
+package send
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/emersion/go-message/mail"
+
+	"git.sr.ht/~rjarry/aerc/worker/types"
+)
+
+func newJmapSender(
+	worker *types.Worker, from *mail.Address, rcpts []*mail.Address,
+) (io.WriteCloser, error) {
+	var writer io.WriteCloser
+	done := make(chan error)
+
+	worker.PostAction(
+		&types.StartSendingMessage{From: from, Rcpts: rcpts},
+		func(msg types.WorkerMessage) {
+			switch msg := msg.(type) {
+			case *types.Done:
+				return
+			case *types.Unsupported:
+				done <- fmt.Errorf("unsupported by worker")
+			case *types.Error:
+				done <- msg.Error
+			case *types.MessageWriter:
+				writer = msg.Writer
+			default:
+				done <- fmt.Errorf("unexpected worker message: %#v", msg)
+			}
+			close(done)
+		},
+	)
+
+	err := <-done
+
+	return writer, err
+}