feat(tracker): load presets from os.UserConfigDir()/sointu/presets/

This is related to #125, but is very crude way of implementing it.

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased
 ### Added
+- User can drop preset instruments into `os.UserConfigDir()/sointu/presets/` and
+  they appear in the list of presets next time sointu is started.
+  ([#125][i125])
 - Ability to loop certain section of the song when playing. The loop can be set
   by using the toggle button in the song panel, or by hitting Ctrl+L.
   ([#128][i128])
@@ -142,6 +145,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [i120]: https://github.com/vsariola/sointu/issues/120
 [i121]: https://github.com/vsariola/sointu/issues/121
 [i122]: https://github.com/vsariola/sointu/issues/122
+[i125]: https://github.com/vsariola/sointu/issues/125
 [i128]: https://github.com/vsariola/sointu/issues/128
 [i129]: https://github.com/vsariola/sointu/issues/129
 [i130]: https://github.com/vsariola/sointu/issues/130

cmd/sointu-vsti/main.go

@@ -61,7 +61,7 @@ func init() {
 		if configDir, err := os.UserConfigDir(); err == nil {
 			randBytes := make([]byte, 16)
 			rand.Read(randBytes)
-			recoveryFile = filepath.Join(configDir, "Sointu", "sointu-vsti-recovery-"+hex.EncodeToString(randBytes))
+			recoveryFile = filepath.Join(configDir, "sointu", "sointu-vsti-recovery-"+hex.EncodeToString(randBytes))
 		}
 		model, player := tracker.NewModelPlayer(cmd.MainSynther, recoveryFile)
 		t := gioui.NewTracker(model)

tracker/presets.go

@@ -3,6 +3,8 @@ package tracker
 import (
 	"embed"
 	"io/fs"
+	"os"
+	"path/filepath"
 	"sort"
 
 	"github.com/vsariola/sointu"
@@ -168,12 +170,31 @@ func init() {
 			return nil
 		}
 		var instr sointu.Instrument
-		if yaml.Unmarshal(data, &instr) != nil {
-			return nil
-		}
+		if yaml.Unmarshal(data, &instr) == nil {
 			instrumentPresets = append(instrumentPresets, instr)
+		}
 		return nil
 	})
+	if configDir, err := os.UserConfigDir(); err == nil {
+		userPresets := filepath.Join(configDir, "sointu", "presets")
+		filepath.WalkDir(userPresets, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+			if d.IsDir() {
+				return nil
+			}
+			data, err := os.ReadFile(path)
+			if err != nil {
+				return nil
+			}
+			var instr sointu.Instrument
+			if yaml.Unmarshal(data, &instr) == nil {
+				instrumentPresets = append(instrumentPresets, instr)
+			}
+			return nil
+		})
+	}
 	sort.Sort(instrumentPresets)
 }