feat(ranking): 주간 랭킹 기간 정책을 추가한다

src/main/kotlin/kr/co/vividnext/sodalive/v2/ranking/domain/CreatorRankingPeriodPolicy.kt

@@ -0,0 +1,42 @@
+package kr.co.vividnext.sodalive.v2.ranking.domain
+
+import java.time.DayOfWeek
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.ZonedDateTime
+import java.time.temporal.TemporalAdjusters
+
+class CreatorRankingPeriodPolicy {
+    fun resolveLastCompletedWeek(now: ZonedDateTime): CreatorRankingPeriod {
+        val nowKst = now.withZoneSameInstant(KST_ZONE)
+        val thisWeekMonday = nowKst.toLocalDate()
+            .with(TemporalAdjusters.previousOrSame(DayOfWeek.MONDAY))
+            .atStartOfDay()
+        return CreatorRankingPeriod(
+            startInclusiveKst = thisWeekMonday.minusWeeks(1),
+            endExclusiveKst = thisWeekMonday
+        )
+    }
+
+    fun toUtcRange(period: CreatorRankingPeriod): CreatorRankingUtcRange {
+        return CreatorRankingUtcRange(
+            startInclusiveUtc = period.startInclusiveKst.atZone(KST_ZONE).withZoneSameInstant(UTC_ZONE).toLocalDateTime(),
+            endExclusiveUtc = period.endExclusiveKst.atZone(KST_ZONE).withZoneSameInstant(UTC_ZONE).toLocalDateTime()
+        )
+    }
+
+    companion object {
+        private val KST_ZONE: ZoneId = ZoneId.of("Asia/Seoul")
+        private val UTC_ZONE: ZoneId = ZoneId.of("UTC")
+    }
+}
+
+data class CreatorRankingPeriod(
+    val startInclusiveKst: LocalDateTime,
+    val endExclusiveKst: LocalDateTime
+)
+
+data class CreatorRankingUtcRange(
+    val startInclusiveUtc: LocalDateTime,
+    val endExclusiveUtc: LocalDateTime
+)