2 files changed, 77 insertions, 1 deletions
diff --git a/commands/commands.go b/commands/commands.go
index 2893aa82..3270bee6 100644
--- a/commands/commands.go
+++ b/commands/commands.go
@@ -185,7 +185,12 @@ func GetCompletions(
 ) (options []string, prefix string) {
 	// copy zeroed struct
 	tmp := reflect.New(reflect.TypeOf(cmd)).Interface().(Command)
-	spec := opt.NewCmdSpec(args.Arg(0), tmp)
+	s, err := args.ArgSafe(0)
+	if err != nil {
+		log.Errorf("completions error: %v", err)
+		return options, prefix
+	}
+	spec := opt.NewCmdSpec(s, tmp)
 	return spec.GetCompletions(args)
 }
 
diff --git a/commands/patch/patch.go b/commands/patch/patch.go
new file mode 100644
index 00000000..0807c1fa
--- /dev/null
+++ b/commands/patch/patch.go
@@ -0,0 +1,71 @@
+package patch
+
+import (
+	"errors"
+	"fmt"
+
+	"git.sr.ht/~rjarry/aerc/commands"
+	"git.sr.ht/~rjarry/go-opt"
+)
+
+var (
+	PatchCommands *commands.Commands
+	subCommands   *commands.Commands
+)
+
+func register(cmd commands.Command) {
+	if subCommands == nil {
+		subCommands = commands.NewCommands()
+	}
+	subCommands.Register(cmd)
+}
+
+func registerPatch(cmd commands.Command) {
+	if PatchCommands == nil {
+		PatchCommands = commands.NewCommands()
+	}
+	PatchCommands.Register(cmd)
+}
+
+func init() {
+	registerPatch(Patch{})
+}
+
+type Patch struct {
+	SubCmd commands.Command `opt:"command" action:"ParseSub" complete:"CompleteSubNames"`
+	Args   string           `opt:"..." required:"false" complete:"CompleteSubArgs"`
+}
+
+func (Patch) Aliases() []string {
+	return []string{"patch"}
+}
+
+func (p *Patch) ParseSub(arg string) error {
+	p.SubCmd = subCommands.ByName(arg)
+	if p.SubCmd == nil {
+		return fmt.Errorf("%s unknown sub-command", arg)
+	}
+	return nil
+}
+
+func (*Patch) CompleteSubNames(arg string) []string {
+	options := subCommands.Names()
+	return commands.FilterList(options, arg, nil)
+}
+
+func (p *Patch) CompleteSubArgs(arg string) []string {
+	if p.SubCmd == nil {
+		return nil
+	}
+	// prepend arbitrary string to arg to work with sub-commands
+	options, _ := commands.GetCompletions(p.SubCmd, opt.LexArgs("a "+arg))
+	return options
+}
+
+func (p Patch) Execute(args []string) error {
+	if p.SubCmd == nil {
+		return errors.New("no subcommand found")
+	}
+	a := opt.QuoteArgs(args[1:]...)
+	return commands.ExecuteCommand(p.SubCmd, a.String())
+}