feat: game engine fetch battle api

game/internal/router/handler/battle.go

@@ -0,0 +1,37 @@
+package handler
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+func BattleHandler(c *gin.Context, executor CommandExecutor) {
+	turn := c.Param("turn")
+	t, err := strconv.Atoi(turn)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	if t < 0 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "turn number can't be negative"})
+		return
+	}
+	id := c.Param("uuid")
+	battleID, err := uuid.Parse(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	r, exists, err := executor.FetchBattle(uint(t), battleID)
+	if errorResponse(c, err) {
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": "unknown battle"})
+		return
+	}
+	c.JSON(http.StatusOK, r)
+}