feat(creator-channel): 오디오 탭 조회 정책을 추가한다

src/main/kotlin/kr/co/vividnext/sodalive/v2/creator/channel/audio/domain/CreatorChannelAudioQueryPolicy.kt

@@ -0,0 +1,43 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.audio.domain
+
+import kr.co.vividnext.sodalive.v2.common.domain.ContentSort
+import kr.co.vividnext.sodalive.v2.creator.channel.live.domain.CreatorChannelPage
+import org.springframework.stereotype.Component
+
+@Component
+class CreatorChannelAudioQueryPolicy {
+    fun resolveSort(sort: String?): ContentSort {
+        return runCatching { ContentSort.valueOf(sort ?: ContentSort.LATEST.name) }
+            .getOrDefault(ContentSort.LATEST)
+    }
+
+    fun createPage(page: Int?, size: Int?): CreatorChannelPage {
+        return CreatorChannelPage(
+            page = page?.coerceAtLeast(MIN_PAGE) ?: DEFAULT_PAGE,
+            size = size?.coerceIn(MIN_PAGE_SIZE, MAX_PAGE_SIZE) ?: DEFAULT_PAGE_SIZE
+        )
+    }
+
+    fun <T> limitItems(fetched: List<T>, page: CreatorChannelPage): List<T> {
+        return fetched.take(page.size)
+    }
+
+    fun hasNext(fetched: List<*>, page: CreatorChannelPage): Boolean {
+        return fetched.size > page.size
+    }
+
+    fun purchaseRate(paidAudioContentCount: Int, purchasedAudioContentCount: Int): Double {
+        if (paidAudioContentCount == 0) {
+            return 0.0
+        }
+        return purchasedAudioContentCount.toDouble() / paidAudioContentCount * 100
+    }
+
+    companion object {
+        private const val DEFAULT_PAGE = 0
+        private const val DEFAULT_PAGE_SIZE = 20
+        private const val MIN_PAGE = 0
+        private const val MIN_PAGE_SIZE = 20
+        private const val MAX_PAGE_SIZE = 50
+    }
+}