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
+    }
+}

src/test/kotlin/kr/co/vividnext/sodalive/v2/creator/channel/audio/domain/CreatorChannelAudioQueryPolicyTest.kt

@@ -0,0 +1,56 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.audio.domain
+
+import kr.co.vividnext.sodalive.v2.common.domain.ContentSort
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+
+class CreatorChannelAudioQueryPolicyTest {
+    private val policy = CreatorChannelAudioQueryPolicy()
+
+    @Test
+    @DisplayName("오디오 탭 page 정책은 page와 size를 fallback하고 fetch limit을 계산한다")
+    fun shouldFallbackPageAndSizeForAudioTab() {
+        val minimumPage = policy.createPage(page = -1, size = 10)
+        val maximumPage = policy.createPage(page = 2, size = 100)
+
+        assertEquals(0, minimumPage.page)
+        assertEquals(20, minimumPage.size)
+        assertEquals(0L, minimumPage.offset)
+        assertEquals(21, minimumPage.fetchLimit)
+        assertEquals(2, maximumPage.page)
+        assertEquals(50, maximumPage.size)
+        assertEquals(100L, maximumPage.offset)
+        assertEquals(51, maximumPage.fetchLimit)
+    }
+
+    @Test
+    @DisplayName("오디오 탭 sort 정책은 null과 알 수 없는 값을 LATEST로 fallback한다")
+    fun shouldFallbackInvalidSortToLatest() {
+        assertEquals(ContentSort.LATEST, policy.resolveSort(null))
+        assertEquals(ContentSort.LATEST, policy.resolveSort("UNKNOWN"))
+        assertEquals(ContentSort.POPULAR, policy.resolveSort("POPULAR"))
+    }
+
+    @Test
+    @DisplayName("오디오 탭 목록 정책은 요청 size만 남기고 다음 페이지 여부를 계산한다")
+    fun shouldLimitItemsAndCalculateHasNext() {
+        val page = policy.createPage(page = 0, size = 20)
+        val fetched = (1..21).toList()
+
+        val items = policy.limitItems(fetched, page)
+
+        assertEquals((1..20).toList(), items)
+        assertTrue(policy.hasNext(fetched, page))
+        assertFalse(policy.hasNext((1..20).toList(), page))
+    }
+
+    @Test
+    @DisplayName("오디오 탭 소장률은 유료 콘텐츠가 없으면 0이고 있으면 백분율로 계산한다")
+    fun shouldCalculatePurchaseRate() {
+        assertEquals(0.0, policy.purchaseRate(paidAudioContentCount = 0, purchasedAudioContentCount = 3))
+        assertEquals(75.0, policy.purchaseRate(paidAudioContentCount = 4, purchasedAudioContentCount = 3))
+    }
+}