feat(tracker, gioui): add confirmation dialogs before quit/new/load song

This should avoid accidentally losing all work by destroying window.

tracker/gioui/dialog.go

@@ -10,6 +10,7 @@ import (
 
 type Dialog struct {
 	Visible   bool
+	BtnAlt    widget.Clickable
 	BtnOk     widget.Clickable
 	BtnCancel widget.Clickable
 }
@@ -18,6 +19,8 @@ type DialogStyle struct {
 	dialog      *Dialog
 	Text        string
 	Inset       layout.Inset
+	ShowAlt     bool
+	AltStyle    material.ButtonStyle
 	OkStyle     material.ButtonStyle
 	CancelStyle material.ButtonStyle
 }
@@ -27,9 +30,11 @@ func ConfirmDialog(th *material.Theme, dialog *Dialog, text string) DialogStyle
 		dialog:      dialog,
 		Text:        text,
 		Inset:       layout.Inset{Top: unit.Dp(12), Bottom: unit.Dp(12), Left: unit.Dp(20), Right: unit.Dp(20)},
+		AltStyle:    material.Button(th, &dialog.BtnAlt, "Alt"),
 		OkStyle:     material.Button(th, &dialog.BtnOk, "Ok"),
 		CancelStyle: material.Button(th, &dialog.BtnCancel, "Cancel"),
 	}
+	ret.AltStyle.Background = primaryColor
 	ret.OkStyle.Background = primaryColor
 	ret.CancelStyle.Background = primaryColor
 	return ret
@@ -45,6 +50,13 @@ func (d *DialogStyle) Layout(gtx C) D {
 						layout.Rigid(Label(d.Text, highEmphasisTextColor)),
 						layout.Rigid(func(gtx C) D {
 							gtx.Constraints.Min.X = gtx.Px(unit.Dp(120))
+							if d.ShowAlt {
+								return layout.Flex{Axis: layout.Horizontal, Spacing: layout.SpaceBetween}.Layout(gtx,
+									layout.Rigid(d.OkStyle.Layout),
+									layout.Rigid(d.AltStyle.Layout),
+									layout.Rigid(d.CancelStyle.Layout),
+								)
+							}
 							return layout.Flex{Axis: layout.Horizontal, Spacing: layout.SpaceBetween}.Layout(gtx,
 								layout.Rigid(d.OkStyle.Layout),
 								layout.Rigid(d.CancelStyle.Layout),

tracker/gioui/files.go

@@ -4,9 +4,11 @@ package gioui
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"path/filepath"
 
+	"gioui.org/app"
 	"gopkg.in/yaml.v3"
 
 	"github.com/sqweek/dialog"
@@ -14,6 +16,30 @@ import (
 )
 
 func (t *Tracker) LoadSongFile() {
+	if t.ChangedSinceSave() {
+		t.ConfirmSongActionType = ConfirmLoad
+		t.ConfirmSongDialog.Visible = true
+		return
+	}
+	t.loadSong()
+}
+
+func (t *Tracker) SaveSongFile() bool {
+	if p := t.FilePath(); p != "" {
+		return t.saveSong(p)
+	}
+	return t.SaveSongAsFile()
+}
+
+func (t *Tracker) SaveSongAsFile() bool {
+	filename, err := dialog.File().Filter("Sointu YAML song", "yml").Filter("Sointu JSON song", "json").Title("Save song").Save()
+	if err != nil {
+		return false
+	}
+	return t.saveSong(filename)
+}
+
+func (t *Tracker) loadSong() {
 	filename, err := dialog.File().Filter("Sointu YAML song", "yml").Filter("Sointu JSON song", "json").Title("Load song").Load()
 	if err != nil {
 		return
@@ -29,25 +55,30 @@ func (t *Tracker) LoadSongFile() {
 		}
 	}
 	t.SetSong(song)
+	t.SetFilePath(filename)
+	t.window.Option(app.Title(fmt.Sprintf("Sointu Tracker - %v", filename)))
+	t.ClearUndoHistory()
+	t.SetChangedSinceSave(false)
 }
 
-func (t *Tracker) SaveSongFile() {
-	filename, err := dialog.File().Filter("Sointu YAML song", "yml").Filter("Sointu JSON song", "json").Title("Save song").Save()
-	if err != nil {
-		return
-	}
+func (t *Tracker) saveSong(filename string) bool {
 	var extension = filepath.Ext(filename)
 	var contents []byte
+	var err error
 	if extension == "json" {
 		contents, err = json.Marshal(t.Song())
 	} else {
 		contents, err = yaml.Marshal(t.Song())
 	}
 	if err != nil {
-		return
+		return false
 	}
 	if extension == "" {
 		filename = filename + ".yml"
 	}
 	ioutil.WriteFile(filename, contents, 0644)
+	t.SetFilePath(filename)
+	t.window.Option(app.Title(fmt.Sprintf("Sointu Tracker - %v", filename)))
+	t.SetChangedSinceSave(false)
+	return true
 }

tracker/gioui/keyevent.go

@@ -111,7 +111,7 @@ func (t *Tracker) KeyEvent(w *app.Window, e key.Event) bool {
 			}
 		case "N":
 			if e.Modifiers.Contain(key.ModShortcut) {
-				t.ResetSong()
+				t.TryResetSong()
 				return true
 			}
 		case "S":

tracker/gioui/layout.go

@@ -3,6 +3,7 @@ package gioui
 import (
 	"image"
 
+	"gioui.org/app"
 	"gioui.org/layout"
 	"gioui.org/op/clip"
 	"gioui.org/op/paint"
@@ -20,6 +21,62 @@ func (t *Tracker) Layout(gtx layout.Context) {
 	t.Alert.Layout(gtx)
 	dstyle := ConfirmDialog(t.Theme, t.ConfirmInstrDelete, "Are you sure you want to delete this instrument?")
 	dstyle.Layout(gtx)
+	dstyle = ConfirmDialog(t.Theme, t.ConfirmSongDialog, "Do you want to save your changes to the song? Your changes will be lost if you don't save them.")
+	dstyle.ShowAlt = true
+	dstyle.OkStyle.Text = "Save"
+	dstyle.AltStyle.Text = "Don't save"
+	dstyle.Layout(gtx)
+	for t.ConfirmSongDialog.BtnOk.Clicked() {
+		if t.SaveSongFile() {
+			t.confirmedSongAction()
+		}
+		t.ConfirmSongDialog.Visible = false
+	}
+	for t.ConfirmSongDialog.BtnAlt.Clicked() {
+		t.confirmedSongAction()
+		t.ConfirmSongDialog.Visible = false
+	}
+	for t.ConfirmSongDialog.BtnCancel.Clicked() {
+		t.ConfirmSongDialog.Visible = false
+	}
+}
+
+func (t *Tracker) confirmedSongAction() {
+	switch t.ConfirmSongActionType {
+	case ConfirmLoad:
+		t.loadSong()
+	case ConfirmNew:
+		t.ResetSong()
+		t.SetFilePath("")
+		t.window.Option(app.Title("Sointu Tracker"))
+		t.ClearUndoHistory()
+		t.SetChangedSinceSave(false)
+	case ConfirmQuit:
+		t.quitted = true
+	}
+}
+
+func (t *Tracker) TryResetSong() {
+	if t.ChangedSinceSave() {
+		t.ConfirmSongActionType = ConfirmNew
+		t.ConfirmSongDialog.Visible = true
+		return
+	}
+	t.ResetSong()
+	t.SetFilePath("")
+	t.window.Option(app.Title("Sointu Tracker"))
+	t.ClearUndoHistory()
+	t.SetChangedSinceSave(false)
+}
+
+func (t *Tracker) TryQuit() bool {
+	if t.ChangedSinceSave() {
+		t.ConfirmSongActionType = ConfirmQuit
+		t.ConfirmSongDialog.Visible = true
+		return false
+	}
+	t.quitted = true
+	return true
 }
 
 func (t *Tracker) layoutBottom(gtx layout.Context) layout.Dimensions {

tracker/gioui/run.go

@@ -36,7 +36,13 @@ func (t *Tracker) Run(w *app.Window) error {
 		case e := <-w.Events():
 			switch e := e.(type) {
 			case system.DestroyEvent:
-				return e.Err
+				if !t.TryQuit() {
+					// TODO: uh oh, there's no way of canceling the destroyevent in gioui? so we create a new window just to show the dialog
+					w = app.NewWindow(
+						app.Size(unit.Dp(800), unit.Dp(600)),
+						app.Title("Sointu Tracker"),
+					)
+				}
 			case key.Event:
 				if t.KeyEvent(w, e) {
 					w.Invalidate()
@@ -52,6 +58,9 @@ func (t *Tracker) Run(w *app.Window) error {
 				e.Frame(gtx.Ops)
 			}
 		}
+		if t.quitted {
+			return nil
+		}
 	}
 }
 
@@ -61,7 +70,7 @@ func Main(audioContext sointu.AudioContext, synthService sointu.SynthService, sy
 			app.Size(unit.Dp(800), unit.Dp(600)),
 			app.Title("Sointu Tracker"),
 		)
-		t := New(audioContext, synthService, syncChannel)
+		t := New(audioContext, synthService, syncChannel, w)
 		defer t.Close()
 		if err := t.Run(w); err != nil {
 			fmt.Println(err)

tracker/gioui/songpanel.go

@@ -53,11 +53,15 @@ func (t *Tracker) layoutMenuBar(gtx C) D {
 	for clickedItem, hasClicked := t.Menus[0].Clicked(); hasClicked; {
 		switch clickedItem {
 		case 0:
-			t.ResetSong()
+			t.TryResetSong()
 		case 1:
 			t.LoadSongFile()
 		case 2:
 			t.SaveSongFile()
+		case 3:
+			t.SaveSongAsFile()
+		case 4:
+			t.TryQuit()
 		}
 		clickedItem, hasClicked = t.Menus[0].Clicked()
 	}
@@ -88,6 +92,8 @@ func (t *Tracker) layoutMenuBar(gtx C) D {
 			MenuItem{IconBytes: icons.ContentClear, Text: "New Song", ShortcutText: shortcutKey + "N"},
 			MenuItem{IconBytes: icons.FileFolder, Text: "Open Song", ShortcutText: shortcutKey + "O"},
 			MenuItem{IconBytes: icons.ContentSave, Text: "Save Song", ShortcutText: shortcutKey + "S"},
+			MenuItem{IconBytes: icons.ContentSave, Text: "Save Song As..."},
+			MenuItem{IconBytes: icons.ActionExitToApp, Text: "Quit"},
 		)),
 		layout.Rigid(t.layoutMenu("Edit", &t.MenuBar[1], &t.Menus[1], unit.Dp(160),
 			MenuItem{IconBytes: icons.ContentUndo, Text: "Undo", ShortcutText: shortcutKey + "Z", Disabled: !t.CanUndo()},

tracker/gioui/tracker.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 
+	"gioui.org/app"
 	"gioui.org/font/gofont"
 	"gioui.org/layout"
 	"gioui.org/text"
@@ -15,6 +16,12 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+const (
+	ConfirmQuit = iota
+	ConfirmLoad
+	ConfirmNew
+)
+
 type Tracker struct {
 	Theme                 *material.Theme
 	MenuBar               []widget.Clickable
@@ -62,6 +69,9 @@ type Tracker struct {
 	PatternOrderList      *layout.List
 	PatternOrderScrollBar *ScrollBar
 	ConfirmInstrDelete    *Dialog
+	ConfirmSongDialog     *Dialog
+	ConfirmSongActionType int
+	window                *app.Window
 
 	lastVolume tracker.Volume
 	volumeChan chan tracker.Volume
@@ -70,6 +80,7 @@ type Tracker struct {
 	refresh      chan struct{}
 	playerCloser chan struct{}
 	errorChannel chan error
+	quitted      bool
 	audioContext sointu.AudioContext
 
 	*tracker.Model
@@ -105,7 +116,7 @@ func (t *Tracker) Close() {
 	t.audioContext.Close()
 }
 
-func New(audioContext sointu.AudioContext, synthService sointu.SynthService, syncChannel chan<- []float32) *Tracker {
+func New(audioContext sointu.AudioContext, synthService sointu.SynthService, syncChannel chan<- []float32, window *app.Window) *Tracker {
 	t := &Tracker{
 		Theme:                 material.NewTheme(gofont.Collection()),
 		audioContext:          audioContext,
@@ -153,7 +164,9 @@ func New(audioContext sointu.AudioContext, synthService sointu.SynthService, syn
 		PatternOrderList:      &layout.List{Axis: layout.Vertical},
 		PatternOrderScrollBar: &ScrollBar{Axis: layout.Vertical},
 		ConfirmInstrDelete:    new(Dialog),
+		ConfirmSongDialog:     new(Dialog),
 		errorChannel:          make(chan error, 32),
+		window:                window,
 	}
 	t.Model = tracker.NewModel()
 	vuBufferObserver := make(chan []float32)

tracker/model.go

@@ -17,18 +17,20 @@ import (
 // accidental mutations in the song. But at least the value members are
 // protected.
 type Model struct {
-	song            sointu.Song
-	editMode        EditMode
-	selectionCorner SongPoint
-	cursor          SongPoint
-	lowNibble       bool
-	instrIndex      int
-	unitIndex       int
-	paramIndex      int
-	octave          int
-	noteTracking    bool
-	usedIDs         map[int]bool
-	maxID           int
+	song             sointu.Song
+	editMode         EditMode
+	selectionCorner  SongPoint
+	cursor           SongPoint
+	lowNibble        bool
+	instrIndex       int
+	unitIndex        int
+	paramIndex       int
+	octave           int
+	noteTracking     bool
+	usedIDs          map[int]bool
+	maxID            int
+	filePath         string
+	changedSinceSave bool
 
 	prevUndoType    string
 	undoSkipCounter int
@@ -76,8 +78,26 @@ func NewModel() *Model {
 	return ret
 }
 
+func (m *Model) FilePath() string {
+	return m.filePath
+}
+
+func (m *Model) SetFilePath(value string) {
+	m.filePath = value
+}
+
+func (m *Model) ChangedSinceSave() bool {
+	return m.changedSinceSave
+}
+
+func (m *Model) SetChangedSinceSave(value bool) {
+	m.changedSinceSave = value
+}
+
 func (m *Model) ResetSong() {
 	m.SetSong(defaultSong.Copy())
+	m.filePath = ""
+	m.changedSinceSave = false
 }
 
 func (m *Model) SetSong(song sointu.Song) {
@@ -671,6 +691,15 @@ func (m *Model) CanUndo() bool {
 	return len(m.undoStack) > 0
 }
 
+func (m *Model) ClearUndoHistory() {
+	if len(m.undoStack) > 0 {
+		m.undoStack = m.undoStack[:0]
+	}
+	if len(m.redoStack) > 0 {
+		m.redoStack = m.redoStack[:0]
+	}
+}
+
 func (m *Model) Redo() {
 	if !m.CanRedo() {
 		return
@@ -986,6 +1015,7 @@ func (m *Model) saveUndo(undoType string, undoSkipping int) {
 		m.undoSkipCounter++
 		return
 	}
+	m.changedSinceSave = true
 	m.prevUndoType = undoType
 	m.undoSkipCounter = 0
 	if len(m.undoStack) >= maxUndo {