feat: implemented 'D' action, tested

internal/action/action.go

@@ -57,6 +57,7 @@ type Model interface {
 	SetCursorX(x int)
 	SetCursorY(y int)
 	ClampCursorX()
+	ClampCursorXNormal()
 
 	// Window
 	ScrollY() int

internal/action/delete.go

@@ -21,3 +21,56 @@ func (a DeleteChar) Execute(m Model) tea.Cmd {
 func (a DeleteChar) WithCount(n int) Action {
 	return DeleteChar{Count: n}
 }
+
+type DeleteToEndOfLine struct {
+	Count int
+}
+
+func (a DeleteToEndOfLine) Execute(m Model) tea.Cmd {
+	// Delete to end of line
+	pos := m.CursorX()
+	line := m.Line(m.CursorY())
+
+	m.SetLine(m.CursorY(), line[:pos])
+	m.SetCursorX(pos - 1)
+
+	// If count is greater, than we will delete the next N - 1 lines below
+	initY := m.CursorY()
+	if a.Count > 1 {
+		// Copied from `internal/operator/delete.go`
+		opCount := min(a.Count-1, m.LineCount()-m.CursorY())
+
+		// Down one
+		m.SetCursorY(initY + 1)
+
+		for range opCount {
+			y := m.CursorY() // Changed from the copied code
+
+			// Stop if were on the starting line
+			if y == initY {
+				break
+			}
+			m.DeleteLine(y)
+
+			if m.LineCount() == 0 {
+				m.InsertLine(0, "")
+			}
+
+			if y >= m.LineCount() {
+				y = m.LineCount() - 1
+			}
+
+			m.SetCursorY(y)
+			m.ClampCursorX()
+		}
+	}
+
+	m.SetCursorY(initY)
+	m.ClampCursorX()
+
+	return nil
+}
+
+func (a DeleteToEndOfLine) WithCount(n int) Action {
+	return DeleteToEndOfLine{Count: n}
+}

internal/editor/integration_delete_test.go

@@ -86,3 +86,92 @@ func TestDeleteCharWithCount(t *testing.T) {
 		}
 	})
 }
+
+func TestDeleteToEndOfLine(t *testing.T) {
+	t.Run("test 'D' deletes to end of line", func(t *testing.T) {
+		lines := []string{"hello world"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, action.Position{Col: 5, Line: 0})
+		sendKeys(tm, "D")
+
+		m := getFinalModel(t, tm)
+		if m.Line(0) != "hello" {
+			t.Errorf("Line(0) = %q, want 'hello'", m.Line(0))
+		}
+	})
+
+	t.Run("test 'D' from start of line deletes entire content", func(t *testing.T) {
+		lines := []string{"hello world"}
+		tm := newTestModelWithLines(t, lines)
+		sendKeys(tm, "D")
+
+		m := getFinalModel(t, tm)
+		if m.Line(0) != "" {
+			t.Errorf("Line(0) = %q, want ''", m.Line(0))
+		}
+	})
+
+	t.Run("test 'D' at last character", func(t *testing.T) {
+		lines := []string{"hello"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, action.Position{Col: 4, Line: 0})
+		sendKeys(tm, "D")
+
+		m := getFinalModel(t, tm)
+		if m.Line(0) != "hell" {
+			t.Errorf("Line(0) = %q, want 'hell'", m.Line(0))
+		}
+	})
+
+	t.Run("test 'D' cursor position after delete", func(t *testing.T) {
+		lines := []string{"hello world"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, action.Position{Col: 5, Line: 0})
+		sendKeys(tm, "D")
+
+		m := getFinalModel(t, tm)
+		// Cursor should move to last character of remaining text
+		if m.CursorX() != 4 {
+			t.Errorf("CursorX() = %d, want 4", m.CursorX())
+		}
+	})
+
+	t.Run("test 'D' deletes nothing on blank line", func(t *testing.T) {
+		lines := []string{""}
+		tm := newTestModelWithLines(t, lines)
+		sendKeys(tm, "D")
+
+		m := getFinalModel(t, tm)
+		if m.Line(0) != "" {
+			t.Errorf("Line(0) = %q, want ''", m.Line(0))
+		}
+	})
+
+	t.Run("test 'D' with count deletes following lines", func(t *testing.T) {
+		lines := []string{"hello", "world", "hi", "mom"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, action.Position{Col: 2, Line: 0})
+		sendKeys(tm, "2", "D")
+
+		m := getFinalModel(t, tm)
+		if m.LineCount() != 3 {
+			t.Errorf("LineCount() = %q, want '3'", m.LineCount())
+		}
+		if m.Line(0) != "he" {
+			t.Errorf("Line(0) = %q, want 'he'", m.Line(0))
+		}
+		if m.Line(1) != "hi" {
+			t.Errorf("Line(1) = %q, want 'hi'", m.Line(1))
+		}
+	})
+
+	t.Run("test 'D' with count deletes following lines with overflow", func(t *testing.T) {
+		lines := []string{"hello", "world", "hi", "mom"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, action.Position{Col: 2, Line: 0})
+		sendKeys(tm, "8", "D")
+
+		m := getFinalModel(t, tm)
+		if m.LineCount() != 1 {
+			t.Errorf("LineCount() = %q, want '1'", m.LineCount())
+		}
+		if m.Line(0) != "he" {
+			t.Errorf("Line(0) = %q, want 'he'", m.Line(0))
+		}
+	})
+}

internal/input/keymap.go

@@ -50,6 +50,7 @@ func NewNormalKeymap() *Keymap {
 			"v":      action.EnterVisualMode{},
 			"V":      action.EnterVisualLineMode{},
 			"ctrl+v": action.EnterVisualBlockMode{},
+			"D":      action.DeleteToEndOfLine{Count: 1},
 		},
 	}
 }