✨ (random): add random tile function

Author: yuanyu90221

internal/game.go

@@ -3,15 +3,26 @@ package internal
 // sideSize - 預設 sideSize
 const sideSize = 4
 
+// randomPositioner - 根據給訂的 TotalSize 隨機產生一個位置
+type randomPositoner func(TotalSize int) int
+
+// randomGenerator - 隨機給個 0 - 1 之間的機率數
+type randomGenerator func() float64
+
 // Game - 紀錄當下遊戲處理狀態
 //
 //	board [][]int - 紀錄盤面狀態
 type Game struct {
-	board [][]int
+	board               [][]int
+	randomPositonerFunc randomPositoner
+	randomFunc          randomGenerator
 }
 
 // Init - 初始化
-func (g *Game) Init(data [][]int) {
+func (g *Game) Init(data [][]int, randomPosFunc randomPositoner, randomFunc randomGenerator) {
+	// setup random functions
+	g.randomPositonerFunc = randomPosFunc
+	g.randomFunc = randomFunc
 	// 建立棋盤
 	g.board = make([][]int, sideSize)
 	for index := range g.board {
@@ -31,6 +42,35 @@ func (g *Game) Init(data [][]int) {
 	}
 }
 
+// addRandomTile - 新增隨機的 2 或是 4 到一個空的 tile 內
+func (g *Game) addRandomTile() {
+	// 蒐集所有空的 tile
+	emptyTiles := make([][2]int, 0, sideSize*sideSize)
+	for r := 0; r < sideSize; r++ {
+		for c := 0; c < sideSize; c++ {
+			if g.board[r][c] == 0 {
+				emptyTiles = append(emptyTiles, [2]int{r, c})
+			}
+		}
+	}
+	// 如果所有格子都滿了
+	if len(emptyTiles) == 0 {
+		return
+	}
+	// 選出要填入的位置
+	position := emptyTiles[g.randomPositonerFunc(len(emptyTiles))]
+	// 90% 機率是 2 , 10%  機率則為 4
+	value := 2
+	if g.randomFunc() < 0.1 {
+		value = 4
+	}
+	g.board[position[0]][position[1]] = value
+}
+
 func NewGame() *Game {
-	return &Game{}
+	return &Game{
+		nil,
+		defaultRandomPositioner,
+		defaultRandomFunc,
+	}
 }

internal/game_test.go

@@ -99,8 +99,147 @@ func TestGameInit(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			game := NewGame()
-			game.Init(tt.input.board)
+			game.Init(tt.input.board, nil, nil)
 			assert.Equal(t, tt.want, game.board)
 		})
 	}
 }
+
+func TestGameRandTile(t *testing.T) {
+	type field struct {
+		board         [][]int
+		randomPosFunc randomPositoner
+		randomFunc    randomGenerator
+	}
+	tests := []struct {
+		name  string
+		input field
+		want  [][]int
+	}{
+		{
+			name: "Case1",
+			input: field{
+				board: [][]int{
+					{0, 0, 0, 0},
+					{0, 2, 0, 0},
+					{0, 0, 0, 0},
+					{0, 0, 0, 4},
+				},
+				randomPosFunc: func(TotalSize int) int {
+					return 1
+				},
+				randomFunc: func() float64 {
+					return 0.2
+				},
+			},
+			want: [][]int{
+				{0, 2, 0, 0},
+				{0, 2, 0, 0},
+				{0, 0, 0, 0},
+				{0, 0, 0, 4},
+			},
+		},
+		{
+			name: "Case2",
+			input: field{
+				board: [][]int{
+					{2, 4, 8, 16},
+					{32, 64, 128, 256},
+					{512, 1024, 2048, 0},
+					{2, 4, 8, 16},
+				},
+				randomPosFunc: func(TotalSize int) int {
+					return 0
+				},
+				randomFunc: func() float64 {
+					return 0.09
+				},
+			},
+			want: [][]int{
+				{2, 4, 8, 16},
+				{32, 64, 128, 256},
+				{512, 1024, 2048, 4},
+				{2, 4, 8, 16},
+			},
+		},
+		{
+			name: "Case3",
+			input: field{
+				board: [][]int{
+					{2, 4, 2, 4},
+					{4, 2, 4, 2},
+					{2, 4, 2, 4},
+					{4, 2, 4, 0},
+				},
+				randomPosFunc: func(TotalSize int) int {
+					return 0
+				},
+				randomFunc: func() float64 {
+					return 0.5
+				},
+			},
+			want: [][]int{
+				{2, 4, 2, 4},
+				{4, 2, 4, 2},
+				{2, 4, 2, 4},
+				{4, 2, 4, 2},
+			},
+		},
+		{
+			name: "Case4",
+			input: field{
+				board: [][]int{
+					{8, 16, 32, 2},
+					{4, 2, 8, 4},
+					{16, 32, 4, 8},
+					{2, 4, 16, 0},
+				},
+				randomPosFunc: func(TotalSize int) int {
+					return 0
+				},
+				randomFunc: func() float64 {
+					return 0.5
+				},
+			},
+			want: [][]int{
+				{8, 16, 32, 2},
+				{4, 2, 8, 4},
+				{16, 32, 4, 8},
+				{2, 4, 16, 2},
+			},
+		},
+		{
+			name: "Case5 - full of tile no change",
+			input: field{
+				board: [][]int{
+					{2, 4, 8, 16},
+					{32, 64, 128, 256},
+					{512, 1024, 2048, 2},
+					{4, 8, 16, 32},
+				},
+				randomPosFunc: func(TotalSize int) int {
+					return 0
+				},
+				randomFunc: func() float64 {
+					return 0.5
+				},
+			},
+			want: [][]int{
+				{2, 4, 8, 16},
+				{32, 64, 128, 256},
+				{512, 1024, 2048, 2},
+				{4, 8, 16, 32},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			game := NewGame()
+			game.Init(tt.input.board, tt.input.randomPosFunc, tt.input.randomFunc)
+			// 模擬隨機產生 tile
+			game.addRandomTile()
+			assert.Equal(t, tt.want, game.board)
+		})
+	}
+
+}

internal/random.go

@@ -0,0 +1,19 @@
+package internal
+
+import (
+	"math/rand"
+	"time"
+)
+
+var defaultRandomPositioner randomPositoner = func(totalSize int) int {
+	if totalSize == 1 {
+		return 0
+	}
+	rand.New(rand.NewSource(time.Now().UnixNano()))
+	return rand.Intn(totalSize)
+}
+
+var defaultRandomFunc randomGenerator = func() float64 {
+	rand.New(rand.NewSource(time.Now().UnixNano()))
+	return rand.Float64()
+}