2 files changed, 41 insertions, 0 deletions
diff --git a/internal/ui/detail_handlers.go b/internal/ui/detail_handlers.go
index 0f5a208..05ea7c4 100644
--- a/internal/ui/detail_handlers.go
+++ b/internal/ui/detail_handlers.go
@@ -77,6 +77,10 @@ func (m *Model) handleTaskDetailMode(msg tea.KeyPressMsg) (tea.Model, tea.Cmd) {
 		return m, nil
 	case "o":
 		return m.handleOpenURL()
+	case "d":
+		return m.handleDetailMarkDone()
+	case "U":
+		return m.handleDetailUndo()
 	case "i", "enter":
 		// Check if current field is editable
 		return m.handleDetailFieldEdit()
@@ -85,6 +89,42 @@ func (m *Model) handleTaskDetailMode(msg tea.KeyPressMsg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// handleDetailMarkDone marks the task currently displayed in the detail view
+// as done. The detail view is closed first so the underlying table is visible
+// for the blink animation and so the (now-completed) task isn't shown as
+// pending after the reload triggered by startBlink.
+func (m *Model) handleDetailMarkDone() (tea.Model, tea.Cmd) {
+	if m.currentTaskDetail == nil {
+		return m, nil
+	}
+	id := m.currentTaskDetail.ID
+	m.closeDetailView()
+	return m, m.startBlink(id, true)
+}
+
+// handleDetailUndo restores the most recently completed task from the undo
+// stack. The detail view is closed first because the undone task generally
+// differs from the one currently displayed, and handleUndo blinks the
+// restored row in the table.
+func (m *Model) handleDetailUndo() (tea.Model, tea.Cmd) {
+	if len(m.undoStack) == 0 {
+		return m, nil
+	}
+	m.closeDetailView()
+	return m.handleUndo()
+}
+
+// closeDetailView resets the detail-view state so the table view is shown
+// again. Used by detail-view actions that intentionally exit the view (mark
+// done, undo).
+func (m *Model) closeDetailView() {
+	m.showTaskDetail = false
+	m.currentTaskDetail = nil
+	m.detailSearching = false
+	m.detailSearchRegex = nil
+	m.detailSearchInput.SetValue("")
+}
+
 // handleDetailFieldEdit starts editing for the currently-selected field in the
 // detail view. Fields 0-2 (ID, UUID, Status) and 6, 8 (Start, Entry) are
 // read-only; all others delegate to the appropriate activation helper.
diff --git a/internal/ui/taskdetail.go b/internal/ui/taskdetail.go
index 94e2ea9..eaf0b45 100644
--- a/internal/ui/taskdetail.go
+++ b/internal/ui/taskdetail.go
@@ -297,6 +297,7 @@ func (m *Model) renderDetailFooter(lines []string) []string {
 		lines = append(lines, ist.Render("Press ESC or q to return to table view"))
 		lines = append(lines, ist.Render("Use ↑/k and ↓/j to navigate fields"))
 		lines = append(lines, ist.Render("Press i or Enter to edit (Priority, Tags, Due, Recurrence, Description)"))
+		lines = append(lines, ist.Render("Press d to mark task done, U to undo last done"))
 		if m.detailSearching {
 			lines = append(lines, ist.Render("Type to search, Enter to confirm"))
 		} else {