feat!: rewrote the GUI and model for better testability

The Model was getting unmaintanable mess. This is an attempt to refactor/rewrite the Model so that data of certain type is exposed in standardized way, offering certain standard manipulations for that data type, and on the GUI side, certain standard widgets to tied to that data.

This rewrite closes #72, #106 and #120.

tracker/presets.go

@@ -12,23 +12,31 @@ import (
 
 //go:generate go run generate/main.go
 
-// GmDlsEntry is a single sample entry from the gm.dls file
-type GmDlsEntry struct {
-	Start              int    // sample start offset in words
-	LoopStart          int    // loop start offset in words
-	LoopLength         int    // loop length in words
-	SuggestedTranspose int    // suggested transpose in semitones, so that all samples play at same pitch
-	Name               string // sample name
-}
+type (
+	// GmDlsEntry is a single sample entry from the gm.dls file
+	GmDlsEntry struct {
+		Start              int    // sample start offset in words
+		LoopStart          int    // loop start offset in words
+		LoopLength         int    // loop length in words
+		SuggestedTranspose int    // suggested transpose in semitones, so that all samples play at same pitch
+		Name               string // sample name
+	}
 
-// GmDlsEntryMap is a reverse map, to find the index of the GmDlsEntry in the
+	InstrumentPresetYieldFunc func(index int, item string) (ok bool)
+	LoadPreset                struct {
+		Index int
+		*Model
+	}
+)
+
+// gmDlsEntryMap is a reverse map, to find the index of the GmDlsEntry in the
 // GmDlsEntries list based on the sample offset. Do not modify during runtime.
-var GmDlsEntryMap = make(map[vm.SampleOffset]int)
+var gmDlsEntryMap = make(map[vm.SampleOffset]int)
 
 func init() {
 	for i, e := range GmDlsEntries {
 		key := vm.SampleOffset{Start: uint32(e.Start), LoopStart: uint16(e.LoopStart), LoopLength: uint16(e.LoopLength)}
-		GmDlsEntryMap[key] = i
+		gmDlsEntryMap[key] = i
 	}
 }
 
@@ -103,12 +111,6 @@ var defaultSong = sointu.Song{
 		}}},
 }
 
-type delayPreset struct {
-	name    string
-	stereo  int
-	varArgs []int
-}
-
 var reverbs = []delayPreset{
 	{"stereo", 1, []int{1116, 1188, 1276, 1356, 1422, 1492, 1556, 1618,
 		1140, 1212, 1300, 1380, 1446, 1516, 1580, 1642,
@@ -117,11 +119,41 @@ var reverbs = []delayPreset{
 	{"right", 0, []int{1140, 1212, 1300, 1380, 1446, 1516, 1580, 1642}},
 }
 
-type instrumentPresets []sointu.Instrument
+type delayPreset struct {
+	name    string
+	stereo  int
+	varArgs []int
+}
+
+func (m *Model) IterateInstrumentPresets(yield InstrumentPresetYieldFunc) {
+	for index, instr := range instrumentPresets {
+		if !yield(index, instr.Name) {
+			return
+		}
+	}
+}
+
+func (m *Model) LoadPreset(index int) Action {
+	return Action{do: func() {
+		defer m.change("LoadPreset", PatchChange, MajorChange)()
+		if m.d.InstrIndex < 0 {
+			m.d.InstrIndex = 0
+		}
+		m.d.InstrIndex2 = m.d.InstrIndex
+		for m.d.InstrIndex >= len(m.d.Song.Patch) {
+			m.d.Song.Patch = append(m.d.Song.Patch, defaultInstrument.Copy())
+		}
+		m.d.Song.Patch[m.d.InstrIndex] = instrumentPresets[index].Copy()
+	}, allowed: func() bool {
+		return true
+	}}
+}
+
+type instrumentPresetsSlice []sointu.Instrument
 
 //go:embed presets/*
 var instrumentPresetFS embed.FS
-var InstrumentPresets instrumentPresets
+var instrumentPresets instrumentPresetsSlice
 
 func init() {
 	fs.WalkDir(instrumentPresetFS, ".", func(path string, d fs.DirEntry, err error) error {
@@ -139,20 +171,12 @@ func init() {
 		if yaml.Unmarshal(data, &instr) != nil {
 			return nil
 		}
-		InstrumentPresets = append(InstrumentPresets, instr)
+		instrumentPresets = append(instrumentPresets, instr)
 		return nil
 	})
-	sort.Sort(InstrumentPresets)
+	sort.Sort(instrumentPresets)
 }
 
-func (p instrumentPresets) Len() int {
-	return len(p)
-}
-
-func (p instrumentPresets) Less(i, j int) bool {
-	return p[i].Name < p[j].Name
-}
-
-func (p instrumentPresets) Swap(i, j int) {
-	p[i], p[j] = p[j], p[i]
-}
+func (p instrumentPresetsSlice) Len() int           { return len(p) }
+func (p instrumentPresetsSlice) Less(i, j int) bool { return p[i].Name < p[j].Name }
+func (p instrumentPresetsSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }