Add entry history browsing to UI

ui_editor.go

@@ -13,6 +13,9 @@ import (
 )
 
 func (u *ui) loadSelectedEntryIntoEditor() {
+	u.selectedHistoryIndex = -1
+	u.historyIndex.SetText("")
+
 	item, ok := u.selectedEntry()
 	if !ok {
 		u.entryID.SetText("")
@@ -44,6 +47,33 @@ func (u *ui) loadSelectedEntryIntoEditor() {
 	u.exportAttachmentPath.SetText("")
 }
 
+func (u *ui) visibleHistory() []vault.Entry {
+	item, ok := u.selectedEntry()
+	if !ok || len(item.History) == 0 {
+		return nil
+	}
+	return append([]vault.Entry(nil), item.History...)
+}
+
+func (u *ui) selectedHistoryEntry() (vault.Entry, bool) {
+	history := u.visibleHistory()
+	if u.selectedHistoryIndex < 0 || u.selectedHistoryIndex >= len(history) {
+		return vault.Entry{}, false
+	}
+	return history[u.selectedHistoryIndex], true
+}
+
+func (u *ui) selectHistoryVersion(index int) error {
+	history := u.visibleHistory()
+	if index < 0 || index >= len(history) {
+		return fmt.Errorf("history index %d out of range", index)
+	}
+
+	u.selectedHistoryIndex = index
+	u.historyIndex.SetText(strconv.Itoa(index))
+	return nil
+}
+
 func (u *ui) saveEntryAction() error {
 	entry, err := u.editorEntry()
 	if err != nil {
@@ -223,9 +253,9 @@ func (u *ui) removeAttachmentAction() error {
 }
 
 func (u *ui) restoreSelectedHistoryAction() error {
-	index, err := strconv.Atoi(strings.TrimSpace(u.historyIndex.Text()))
+	index, err := u.selectedHistoryVersionIndex()
 	if err != nil {
-		return fmt.Errorf("invalid history index: %w", err)
+		return err
 	}
 	if err := u.state.RestoreSelectedEntryVersion(index); err != nil {
 		return err
@@ -235,6 +265,21 @@ func (u *ui) restoreSelectedHistoryAction() error {
 	return nil
 }
 
+func (u *ui) selectedHistoryVersionIndex() (int, error) {
+	text := strings.TrimSpace(u.historyIndex.Text())
+	if text != "" {
+		index, err := strconv.Atoi(text)
+		if err != nil {
+			return 0, fmt.Errorf("invalid history index: %w", err)
+		}
+		return index, nil
+	}
+	if u.selectedHistoryIndex >= 0 {
+		return u.selectedHistoryIndex, nil
+	}
+	return 0, fmt.Errorf("no history version selected")
+}
+
 func (u *ui) copySelectedFieldAction(target clipboard.Target) error {
 	model, err := u.state.Session.Current()
 	if err != nil {