create basic controller

pkg/repo/game.go

@@ -14,13 +14,17 @@ import (
 	"github.com/iliadenisov/galaxy/pkg/model/game"
 )
 
+const (
+	statePath = "state.json"
+)
+
 func (r *repo) SaveTurn(t uint, g game.Game) error {
 	return saveTurn(r.s, t, g)
 }
 
 func saveTurn(s Storage, t uint, g game.Game) error {
 	path := fmt.Sprintf("%03d/state.json", t)
-	exist, err := s.Exist(path)
+	exist, err := s.Exists(path)
 	if err != nil {
 		return NewStorageError(err)
 	}
@@ -40,9 +44,28 @@ func (r *repo) SaveState(g game.Game) error {
 }
 
 func saveState(s Storage, g game.Game) error {
-	path := "state.json"
-	if err := s.Write(path, g); err != nil {
+	if err := s.Write(statePath, g); err != nil {
 		return NewStorageError(err)
 	}
 	return nil
 }
+
+func (r *repo) LoadState() (game.Game, error) {
+	return loadState(r.s)
+}
+
+func loadState(s Storage) (game.Game, error) {
+	var g game.Game
+	path := statePath
+	exist, err := s.Exists(path)
+	if err != nil {
+		return g, NewStorageError(err)
+	}
+	if !exist {
+		return g, NewStateError("latest state was never stored")
+	}
+	if err := s.Read(path, &g); err != nil {
+		return g, NewStorageError(err)
+	}
+	return g, nil
+}