Implement completion for the save file entry prompt

kittens/choose_files/main.go

@@ -21,8 +21,6 @@ import (
 	"github.com/kovidgoyal/kitty/tools/utils"
 )
 
-// TODO: save file name completion
-
 var _ = fmt.Print
 var debugprintln = tty.DebugPrintln
 
@@ -378,7 +376,15 @@ func (h *Handler) accept_idx(idx CollectionIndex) (accepted bool, err error) {
 				return false, nil
 			}
 			if s.IsDir() {
-				return true, h.change_to_current_dir_if_possible()
+				if h.state.mode.CanSelectNonExistent() {
+					name := h.state.suggested_save_file_name
+					if h.state.SearchText() != "" {
+						name = h.state.SearchText()
+					}
+					h.initialize_save_file_name(name)
+					return true, h.draw_screen()
+				}
+				return false, nil
 			}
 		}
 
@@ -721,9 +727,10 @@ func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
 		return 1, err
 	}
 	lp.MouseTrackingMode(loop.FULL_MOUSE_TRACKING)
-	handler := Handler{lp: lp, err_chan: make(chan error, 8), rl: readline.New(lp, readline.RlInit{
-		Prompt: "> ", ContinuationPrompt: ". ",
-	})}
+	handler := Handler{lp: lp, err_chan: make(chan error, 8)}
+	handler.rl = readline.New(lp, readline.RlInit{
+		Prompt: "> ", ContinuationPrompt: ". ", Completer: handler.complete_save_prompt,
+	})
 	if err = handler.set_state_from_config(conf, opts); err != nil {
 		return 1, err
 	}

kittens/choose_files/save-file.go

@@ -4,13 +4,56 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
+	"github.com/kovidgoyal/kitty/tools/cli"
 	"github.com/kovidgoyal/kitty/tools/tui/loop"
 	"github.com/kovidgoyal/kitty/tools/utils"
 )
 
 var _ = fmt.Print
 
+func (h *Handler) complete_save_prompt(before_cursor, after_cursor string) *cli.Completions {
+	path := before_cursor
+	prefix := ""
+	if idx := strings.Index(path, string(os.PathSeparator)); idx > -1 {
+		prefix = filepath.Dir(path) + string(os.PathSeparator)
+	}
+	if !filepath.IsAbs(path) {
+		path = filepath.Join(h.state.CurrentDir(), path)
+	}
+	dir := filepath.Dir(path)
+	if strings.HasSuffix(before_cursor, string(os.PathSeparator)) {
+		dir = path
+	}
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return nil
+	}
+	ans := cli.NewCompletions()
+	dirs := ans.AddMatchGroup("Directories")
+	dirs.IsFiles = true
+	dirs.NoTrailingSpace = true
+	files := ans.AddMatchGroup("Files")
+	files.IsFiles = true
+	files.NoTrailingSpace = true
+	leading, _ := filepath.Rel(dir, path)
+	if leading == "." {
+		leading = ""
+	}
+	for _, e := range entries {
+		word := e.Name()
+		if leading == "" || strings.HasPrefix(word, leading) {
+			collection := utils.IfElse(e.Type().IsDir(), dirs, files)
+			if prefix != "" {
+				word = prefix + word
+			}
+			collection.Matches = append(collection.Matches, &cli.Match{Word: word})
+		}
+	}
+	return ans
+}
+
 func (h *Handler) current_save_file_path() string {
 	ans := h.rl.AllText()
 	if ans != "" {