Improve LoadableSource implementation

app.go

@@ -73,7 +73,7 @@ func (app *App) loadCustomSources() error {
 		if newss, ok := sources.LoadableSources[csrc.Source]; !ok {
 			return fmt.Errorf("Unable to load source #%d: %q: no such source registered", id, csrc.Source)
 		} else {
-			src, err := newss(csrc.KV)
+			src, err := newss.LoadSource(csrc.KV)
 			if err != nil {
 				return fmt.Errorf("Unable to load source #%d (%s): %w", id, csrc.Source, err)
 			}

settings/settings.go

@@ -10,7 +10,7 @@ import (
 
 type CustomSource struct {
 	Source string                 `json:"src"`
-	KV     map[string]string `json:"kv"`
+	KV     map[string]interface{} `json:"kv"`
 }
 
 type Settings struct {

sources/interfaces.go

@@ -1,6 +1,8 @@
 package sources
 
-import ()
+import (
+	"encoding/json"
+)
 
 var (
 	LoadableSources = map[string]LoadaleSource{}
@@ -19,4 +21,17 @@ type PlayingSource interface {
 	CurrentlyPlaying() string
 }
 
-type LoadaleSource func(map[string]string) (SoundSource, error)
+type LoadaleSource struct {
+	LoadSource       func(map[string]interface{}) (SoundSource, error)
+	Description      string
+	SourceDefinition interface{}
+}
+
+func Unmarshal(in map[string]interface{}, out interface{}) error {
+	jin, err := json.Marshal(in)
+	if err != nil {
+		return err
+	}
+
+	return json.Unmarshal(jin, out)
+}

sources/mpv/source.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"os/exec"
 	"path"
-	"strings"
 	"time"
 
 	"github.com/DexterLB/mpvipc"
@@ -18,31 +17,23 @@ import (
 type MPVSource struct {
 	process      *exec.Cmd
 	ipcSocketDir string
-	Name         string
-	Options      []string
-	File         string
+	Name         string   `json:"name"`
+	Options      []string `json:"opts"`
+	File         string   `json:"file"`
 }
 
 func init() {
-	sources.LoadableSources["mpv"] = NewMPVSource
+	sources.LoadableSources["mpv"] = sources.LoadaleSource{
+		LoadSource:       NewMPVSource,
+		Description:      "Play any file, stream or URL through mpv",
+		SourceDefinition: &MPVSource{},
+	}
 }
 
-func NewMPVSource(kv map[string]string) (sources.SoundSource, error) {
+func NewMPVSource(kv map[string]interface{}) (sources.SoundSource, error) {
 	var s MPVSource
-
-	if name, ok := kv["name"]; ok {
-		s.Name = name
-	}
-
-	if opts, ok := kv["opts"]; ok {
-		s.Options = strings.Split(opts, " ")
-	}
-
-	if file, ok := kv["file"]; ok {
-		s.File = file
-	}
-
-	return &s, nil
+	err := sources.Unmarshal(kv, &s)
+	return &s, err
 }
 
 func (s *MPVSource) GetName() string {