Add change tab command

This command allows the user to change tab by giving the tab name. This
can be tab completed too. The previous tab is stored in the tabs module
so that when a new tab is created it is still possible to go to the
previous one.

Normal invocation is :ct folder
Previous tab is :ct -

1 files changed, 48 insertions, 0 deletions

diff --git a/commands/ct.go b/commands/ct.go
new file mode 100644
index 0000000..ab2993d
--- /dev/null
+++ b/commands/ct.go
@@ -0,0 +1,48 @@
+package commands
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+)
+
+type ChangeTab struct{}
+
+func init() {
+	register(ChangeTab{})
+}
+
+func (_ ChangeTab) Aliases() []string {
+	return []string{"ct", "change-tab"}
+}
+
+func (_ ChangeTab) Complete(aerc *widgets.Aerc, args []string) []string {
+	out := make([]string, 0)
+	for _, tab := range aerc.TabNames() {
+		if strings.HasPrefix(tab, args[0]) {
+			out = append(out, tab)
+		}
+	}
+	return out
+}
+
+func (_ ChangeTab) Execute(aerc *widgets.Aerc, args []string) error {
+	if len(args) != 2 {
+		return errors.New(fmt.Sprintf("Usage: %s <tab>", args[0]))
+	}
+
+	if args[1] == "-" {
+		ok := aerc.SelectPreviousTab()
+		if !ok {
+			return errors.New("No previous tab to return to")
+		}
+	} else {
+		ok := aerc.SelectTab(args[1])
+		if !ok {
+			return errors.New("No tab with that name")
+		}
+	}
+	return nil
+}