Enable to parse multiple format

Author: Takumasa Sakao

Makefile

@@ -4,8 +4,7 @@ ARTIFACTS_DIR=artifacts/${VERSION}
 GITHUB_USERNAME=sachaos
 
 test:
-	go test -v ./format/life106
-	go test -v ./format/rle
+	go test -v ./format/...
 
 prepare:
 	go get github.com/gobuffalo/packr/packr

format/parse.go

@@ -0,0 +1,49 @@
+package format
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"io/ioutil"
+
+	"github.com/sachaos/go-life/format/life106"
+	"github.com/sachaos/go-life/format/rle"
+)
+
+const (
+	Life105 = iota
+	Life106
+	RLE
+)
+
+func Parse(r io.Reader) ([][]bool, error) {
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	formatReader := bytes.NewReader(b)
+	contentReader := bytes.NewReader(b)
+	switch DetectFormat(formatReader) {
+	case Life106:
+		return life106.Parse(contentReader), nil
+	default:
+		return rle.Parse(contentReader), nil
+	}
+}
+
+func DetectFormat(r io.Reader) int {
+	br := bufio.NewReader(r)
+
+	firstLine, _, _ := br.ReadLine()
+	firstLineStr := string(firstLine)
+
+	switch firstLineStr {
+	case "#Life 1.05":
+		return Life105
+	case "#Life 1.06":
+		return Life106
+	default:
+		return RLE
+	}
+}

format/parse_test.go

@@ -0,0 +1,39 @@
+package format
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDetectFormat(t *testing.T) {
+	testCases := []struct {
+		Name           string
+		Filename       string
+		ExpectedFormat int
+	}{
+		{
+			Name:           "life106",
+			Filename:       "./life106/test/glider.life",
+			ExpectedFormat: Life106,
+		},
+		{
+			Name:           "rle",
+			Filename:       "./rle/test/glider.rle",
+			ExpectedFormat: RLE,
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.Name, func(t *testing.T) {
+			f, err := os.Open(testCase.Filename)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			detectedFormat := DetectFormat(f)
+			if detectedFormat != testCase.ExpectedFormat {
+				t.Errorf("ExpectedFormat: %v, but actually: %v", testCase.ExpectedFormat, detectedFormat)
+			}
+		})
+	}
+}

main.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/gdamore/tcell"
 	"github.com/gdamore/tcell/encoding"
-	"github.com/sachaos/go-life/format/rle"
+	"github.com/sachaos/go-life/format"
 	"github.com/sachaos/go-life/preset"
 	"github.com/urfave/cli"
 	"io"
@@ -200,7 +200,10 @@ func main() {
 				}
 			}
 
-			defaultCells = rle.Parse(file)
+			defaultCells, err = format.Parse(file)
+			if err != nil {
+				return err
+			}
 		}
 
 		return startGame(themes, presets, themeIndex, defaultCells)