feat: 포인트 사용 로직 구현 (만료일 순 + 10포인트 단위 차감)

src/main/kotlin/kr/co/vividnext/sodalive/point/MemberPointRepository.kt

@@ -1,5 +1,29 @@
 package kr.co.vividnext.sodalive.point
 
+import com.querydsl.jpa.impl.JPAQueryFactory
+import kr.co.vividnext.sodalive.point.QMemberPoint.memberPoint
 import org.springframework.data.jpa.repository.JpaRepository
+import java.time.LocalDateTime
 
-interface MemberPointRepository : JpaRepository<MemberPoint, Long>
+interface MemberPointRepository : JpaRepository<MemberPoint, Long>, MemberPointQueryRepository
+
+interface MemberPointQueryRepository {
+    fun findByMemberIdAndExpiresAtAfterOrderByExpiresAtAsc(memberId: Long, expiresAt: LocalDateTime): List<MemberPoint>
+}
+
+class MemberPointQueryRepositoryImpl(
+    private val queryFactory: JPAQueryFactory
+) : MemberPointQueryRepository {
+    override fun findByMemberIdAndExpiresAtAfterOrderByExpiresAtAsc(
+        memberId: Long,
+        expiresAt: LocalDateTime
+    ): List<MemberPoint> {
+        return queryFactory
+            .selectFrom(memberPoint)
+            .where(
+                memberPoint.memberId.eq(memberId),
+                memberPoint.expiresAt.goe(expiresAt)
+            )
+            .fetch()
+    }
+}

src/main/kotlin/kr/co/vividnext/sodalive/point/PointUsageService.kt

@@ -0,0 +1,43 @@
+package kr.co.vividnext.sodalive.point
+
+import org.springframework.stereotype.Service
+import java.time.LocalDateTime
+
+@Service
+class PointUsageService(
+    private val memberPointRepository: MemberPointRepository,
+    private val usePointRepository: UsePointRepository
+) {
+    fun usePoint(memberId: Long, contentPrice: Int): Int {
+        val now = LocalDateTime.now()
+        val maxUsablePoint = contentPrice * 10
+
+        val points = memberPointRepository.findByMemberIdAndExpiresAtAfterOrderByExpiresAtAsc(
+            memberId = memberId,
+            expiresAt = now
+        )
+
+        val totalAvailable = points.sumOf { it.point }
+        val usablePoint = minOf(totalAvailable, maxUsablePoint).floorToNearest10()
+
+        var remaining = usablePoint
+        var used = 0
+
+        for (p in points) {
+            if (remaining <= 0) break
+            val usable = minOf(p.point, remaining)
+            p.point -= usable
+            remaining -= usable
+            used += usable
+        }
+
+        if (used > 0) {
+            memberPointRepository.saveAll(points)
+            usePointRepository.save(UsePoint(memberId = memberId, amount = used))
+        }
+
+        return used
+    }
+
+    private fun Int.floorToNearest10(): Int = (this / 10) * 10
+}

src/main/kotlin/kr/co/vividnext/sodalive/point/UsePointRepository.kt

@@ -0,0 +1,5 @@
+package kr.co.vividnext.sodalive.point
+
+import org.springframework.data.jpa.repository.JpaRepository
+
+interface UsePointRepository : JpaRepository<UsePoint, Long>