saving new turn

pkg/repo/fs/fs.go

@@ -75,6 +75,10 @@ func (f *fs) Lock() (func() error, error) {
 	return unlock, nil
 }
 
+func (f *fs) Exist(path string) (bool, error) {
+	return fileExists(filepath.Join(f.root, path))
+}
+
 func (f *fs) Write(path string, v encoding.BinaryMarshaler) error {
 	if v == nil {
 		return errors.New("cant't marshal from nil object")

pkg/repo/fs/fs_test.go

@@ -33,6 +33,27 @@ func TestLock(t *testing.T) {
 	assert.False(t, exists, "lock file must be removed")
 }
 
+func TestExist(t *testing.T) {
+	root, cleanup := createWorkDir(t)
+	defer cleanup()
+
+	fileName := "some-file.ext"
+	if err := os.WriteFile(filepath.Join(root, fileName), []byte{1, 2, 3, 4}, os.ModePerm); err != nil {
+		t.Fatal(err)
+	}
+
+	fs, err := NewFileStorage(root)
+	assert.NoError(t, err, "create file storage")
+
+	exist, err := fs.Exist(fileName)
+	assert.NoError(t, err)
+	assert.True(t, exist)
+
+	exist, err = fs.Exist("random/path")
+	assert.NoError(t, err)
+	assert.False(t, exist)
+}
+
 func TestWrite(t *testing.T) {
 	root, cleanup := createWorkDir(t)
 	defer cleanup()

pkg/repo/game.go

@@ -0,0 +1,48 @@
+package repo
+
+/*
+    /state.json
+	/000/state.json
+	/000/race/{UUID}/order/001.json
+	/000/race/{UUID}/report.json
+	/000/battle/{planet_UUID}
+*/
+
+import (
+	"fmt"
+
+	"github.com/iliadenisov/galaxy/pkg/model/game"
+)
+
+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)
+	if err != nil {
+		return NewStorageError(err)
+	}
+	if exist {
+		return NewStateError(fmt.Sprintf("state for turn %d already saved", t))
+	}
+	if err := s.Write(path, g); err != nil {
+		return NewStorageError(err)
+	}
+	// TODO: save reports
+	// TODO: save battles
+	return saveState(s, g)
+}
+
+func (r *repo) SaveState(g game.Game) error {
+	return saveState(r.s, g)
+}
+
+func saveState(s Storage, g game.Game) error {
+	path := "state.json"
+	if err := s.Write(path, g); err != nil {
+		return NewStorageError(err)
+	}
+	return nil
+}

pkg/repo/repo.go

@@ -2,12 +2,26 @@ package repo
 
 import (
 	"encoding"
+	"errors"
 
 	"github.com/iliadenisov/galaxy/pkg/repo/fs"
 )
 
+type StorageError error
+
+func NewStorageError(err error) error {
+	return StorageError(err)
+}
+
+type StateError error
+
+func NewStateError(msg string) error {
+	return StateError(errors.New(msg))
+}
+
 type Storage interface {
 	Lock() (func() error, error)
+	Exist(string) (bool, error)
 	Write(string, encoding.BinaryMarshaler) error
 	Read(string, encoding.BinaryUnmarshaler) error
 }