feat: copy/paste step (#17)

* feat: copy/paste step
resolves #7

* Rename Copy/Paste Params to Copy/Paste Step

* Move sequencer helper functions to helper.go

* Remove useless comment

* Remove useless comment

---------

Co-authored-by: Xavier Godart <[email protected]>

filesystem/keymap.go

@@ -12,6 +12,8 @@ type KeyMap struct {
 	RemoveTrack  string     `json:"remove_track"`
 	AddStep      string     `json:"add_step"`
 	RemoveStep   string     `json:"remove_step"`
+	CopyStep     string     `json:"copy_step"`
+	PasteStep    string     `json:"paste_step"`
 	PreviousStep string     `json:"previous_step"`
 	NextStep     string     `json:"next_step"`
 	PageUp       string     `json:"page_up"`
@@ -42,6 +44,8 @@ func NewDefaultAzertyKeyMap() KeyMap {
 		RemoveTrack:  ")",
 		AddStep:      "+",
 		RemoveStep:   "°",
+		CopyStep:     "ctrl+c",
+		PasteStep:    "ctrl+v",
 		PreviousStep: ",",
 		NextStep:     ";",
 		PageUp:       "p",
@@ -73,6 +77,8 @@ func NewDefaultAzertyMacKeyMap() KeyMap {
 		RemoveTrack:  ")",
 		AddStep:      "_",
 		RemoveStep:   "°",
+		CopyStep:     "ctrl+c",
+		PasteStep:    "ctrl+v",
 		PreviousStep: ",",
 		NextStep:     ";",
 		PageUp:       "p",
@@ -103,6 +109,8 @@ func NewDefaultQwertyKeyMap() KeyMap {
 		RemoveTrack:  "-",
 		AddStep:      "+",
 		RemoveStep:   "_",
+		CopyStep:     "ctrl+c",
+		PasteStep:    "ctrl+v",
 		PreviousStep: ",",
 		NextStep:     ".",
 		PageUp:       "p",
@@ -134,6 +142,8 @@ func NewDefaultQwertyMacKeyMap() KeyMap {
 		RemoveTrack:  "-",
 		AddStep:      "+",
 		RemoveStep:   "_",
+		CopyStep:     "ctrl+c",
+		PasteStep:    "ctrl+v",
 		PreviousStep: ",",
 		NextStep:     ".",
 		PageUp:       "p",

sequencer/helper.go

@@ -0,0 +1,29 @@
+package sequencer
+
+// Helper functions for deep copying pointers
+func copyIntPtr(ptr *int) *int {
+	if ptr == nil {
+		return nil
+	}
+	copy := *ptr
+	return &copy
+}
+
+func copyUint8Ptr(ptr *uint8) *uint8 {
+	if ptr == nil {
+		return nil
+	}
+	copy := *ptr
+	return &copy
+}
+
+func copyUint8SlicePtr(ptr *[]uint8) *[]uint8 {
+	if ptr == nil {
+		return nil
+	}
+	copy := make([]uint8, len(*ptr))
+	for i, v := range *ptr {
+		copy[i] = v
+	}
+	return &copy
+}

sequencer/sequencer.go

@@ -51,6 +51,8 @@ type Sequencer interface {
 	AddStep(track int)
 	RemoveStep(track int)
 	ToggleStep(track, step int)
+	CopyStep(track, step int)
+	PasteStep(track, step int)
 	Tempo() float64
 	SetTempo(tempo float64)
 	Reset()
@@ -72,6 +74,8 @@ type sequencer struct {
 	isPlaying bool
 
 	isFirstTick bool
+
+	stepClipboard step
 }
 
 // New creates a new sequencer. It also creates new tracks and calls the
@@ -245,6 +249,67 @@ func (s *sequencer) ToggleStep(track, step int) {
 	s.tracks[track].steps[step].clearParameters()
 }
 
+// CopyStep copies a step to the 'clipboard' step.
+func (s *sequencer) CopyStep(track, srcStep int) {
+	if track < 0 || track >= len(s.tracks) || srcStep < 0 || srcStep >= len(s.tracks[track].steps) {
+		return // Out of bounds, do nothing
+	}
+
+	originalStep := s.tracks[track].steps[srcStep]
+
+	// Create a deep copy of the step
+	s.stepClipboard = step{
+		midi:        originalStep.midi,
+		track:       nil,               // We don't want to keep a reference to the original track
+		position:    originalStep.position,
+		active:      originalStep.active,
+		triggered:   false, // Reset triggered state for the copy
+		controls:    make(map[int]*midi.Control),
+		length:      copyIntPtr(originalStep.length),
+		chord:       copyUint8SlicePtr(originalStep.chord),
+		velocity:    copyUint8Ptr(originalStep.velocity),
+		probability: copyIntPtr(originalStep.probability),
+		offset:      originalStep.offset,
+	}
+
+	// Deep copy the controls
+	for k, v := range originalStep.controls {
+		controlCopy := *v // Assuming midi.Control is safe to copy directly
+		s.stepClipboard.controls[k] = &controlCopy
+	}
+}
+
+// PasteStep pastes a clipboard step into a destination step
+func (s *sequencer) PasteStep(track, dstStep int) {
+	if track < 0 || track >= len(s.tracks) || dstStep < 0 || dstStep >= len(s.tracks[track].steps) {
+		return // Out of bounds, do nothing
+	}
+
+	// Create a deep copy of the clipboard
+	newStep := step{
+		midi:        s.stepClipboard.midi,
+		track:       s.tracks[track],
+		position:    dstStep,
+		active:      s.stepClipboard.active,
+		triggered:   false, // Reset triggered state
+		controls:    make(map[int]*midi.Control),
+		length:      copyIntPtr(s.stepClipboard.length),
+		chord:       copyUint8SlicePtr(s.stepClipboard.chord),
+		velocity:    copyUint8Ptr(s.stepClipboard.velocity),
+		probability: copyIntPtr(s.stepClipboard.probability),
+		offset:      s.stepClipboard.offset,
+	}
+
+	// Deep copy the controls
+	for k, v := range s.stepClipboard.controls {
+		controlCopy := *v
+		newStep.controls[k] = &controlCopy
+	}
+
+	// Replace the step in the track
+	s.tracks[track].steps[dstStep] = &newStep
+}
+
 func (s *sequencer) start() {
 	// Each time the clock ticks, we call the sequencer tick method that
 	// basically makes every track move forward in time.

ui/keymap.go

@@ -19,6 +19,8 @@ type keyMap struct {
 
 	AddStep    key.Binding
 	RemoveStep key.Binding
+	CopyStep   key.Binding
+	PasteStep  key.Binding
 
 	NextStep     key.Binding
 	PreviousStep key.Binding
@@ -101,6 +103,14 @@ func newKeyMap(keys filesystem.KeyMap) keyMap {
 			key.WithKeys(keys.RemoveStep),
 			key.WithHelp(keys.RemoveStep, "remove step"),
 		),
+		CopyStep: key.NewBinding(
+			key.WithKeys(keys.CopyStep),
+			key.WithHelp(keys.CopyStep, "copy active step parameters"),
+		),
+		PasteStep: key.NewBinding(
+			key.WithKeys(keys.PasteStep),
+			key.WithHelp(keys.PasteStep, "paste copied parameters into active step"),
+		),
 		PreviousStep: key.NewBinding(
 			key.WithKeys(keys.PreviousStep),
 			key.WithHelp(keys.PreviousStep, "select previous step"),
@@ -178,8 +188,8 @@ func newKeyMap(keys filesystem.KeyMap) keyMap {
 			key.WithHelp(keys.Help, "toggle help"),
 		),
 		Quit: key.NewBinding(
-			key.WithKeys("ctrl+c", "esc"),
-			key.WithHelp("ctrl+c/esc", "quit"),
+			key.WithKeys("ctrl+q", "esc"),
+			key.WithHelp("ctrl+q/esc", "quit"),
 		),
 	}
 	for i, k := range keys.Steps {

ui/ui.go

@@ -218,6 +218,20 @@ func (m mainModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			m.updateParams()
 			return m, nil
 
+		case key.Matches(msg, m.keymap.CopyStep):
+			m.seq.CopyStep(m.activeTrack, m.activeStep)
+			m.mode = stepMode
+			m.stepModeTimer = 0
+			m.updateParams()
+			return m, nil
+
+		case key.Matches(msg, m.keymap.PasteStep):
+			m.seq.PasteStep(m.activeTrack, m.activeStep)
+			m.mode = stepMode
+			m.stepModeTimer = 0
+			m.updateParams()
+			return m, nil
+
 		case key.Matches(msg, m.keymap.StepToggle):
 			number := m.keymap.StepToggleIndex[msg.String()]
 			if m.mode == patternMode {