added local state to cache uploads

internal/localstate.go

@@ -0,0 +1,49 @@
+package steamimmich
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"os"
+)
+
+type AssetState struct {
+	FilePath string
+	ImmichID string
+}
+
+type LocalState struct {
+	Assets []AssetState
+}
+
+func loadLocalState(filename string) (*LocalState, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return &LocalState{Assets: []AssetState{}}, nil
+		}
+		return nil, err
+	}
+
+	content, err := io.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+
+	var data LocalState
+	err = json.Unmarshal(content, &data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &data, nil
+}
+
+func saveLocalState(filename string, state LocalState) error {
+	content, err := json.Marshal(state)
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(filename, content, 0644)
+}