[PM-19840] Migrate BaseEnumeratedIntSerializer to core module (#4975)

core/src/main/kotlin/com/bitwarden/core/data/serializer/BaseEnumeratedIntSerializer.kt

@@ -0,0 +1,46 @@
+package com.bitwarden.core.data.serializer
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+/**
+ * Base [KSerializer] for mapping an [Enum] with possible values given by [values] to/from integer
+ * values, which should be specified using [SerialName]. If a [default] value is provided, it will
+ * be used when an unknown value is provided.
+ */
+@Suppress("UnnecessaryAbstractClass")
+abstract class BaseEnumeratedIntSerializer<T : Enum<T>>(
+    private val className: String,
+    private val values: Array<T>,
+    private val default: T? = null,
+) : KSerializer<T> {
+
+    override val descriptor: SerialDescriptor
+        get() = PrimitiveSerialDescriptor(
+            serialName = this::class.java.simpleName,
+            kind = PrimitiveKind.INT,
+        )
+
+    override fun deserialize(decoder: Decoder): T {
+        val decodedValue = decoder.decodeInt().toString()
+        return values.firstOrNull { it.serialNameAnnotation?.value == decodedValue }
+            ?: default
+            ?: throw IllegalArgumentException("Unknown value $decodedValue for $className")
+    }
+
+    override fun serialize(encoder: Encoder, value: T) {
+        encoder.encodeInt(
+            requireNotNull(
+                value.serialNameAnnotation?.value?.toInt(),
+            ),
+        )
+    }
+
+    private val Enum<*>.serialNameAnnotation: SerialName?
+        get() = javaClass.getDeclaredField(name).getAnnotation(SerialName::class.java)
+}

core/src/test/kotlin/com/bitwarden/core/data/serializer/BaseEnumeratedIntSerializerTest.kt

@@ -0,0 +1,68 @@
+package com.bitwarden.core.data.serializer
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.encodeToJsonElement
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class BaseEnumeratedIntSerializerTest {
+    private val json = Json
+
+    @Test
+    fun `properly deserializes integers to enums`() {
+        assertEquals(
+            TestEnum.CASE_1,
+            json.decodeFromString<TestEnum>(
+                """
+                1
+                """,
+            ),
+        )
+    }
+
+    @Test
+    fun `properly serializes enums back to integers`() {
+        assertEquals(
+            json.parseToJsonElement(
+                """
+                1
+                """,
+            ),
+            json.encodeToJsonElement(
+                TestEnum.CASE_1,
+            ),
+        )
+    }
+
+    @Test
+    fun `properly returns default value when unknown value is provided`() {
+        assertEquals(
+            TestEnum.UNKNOWN,
+            json.decodeFromString<TestEnum>(
+                """
+                -1
+                """,
+            ),
+        )
+    }
+}
+
+@Serializable(TestEnumSerializer::class)
+private enum class TestEnum {
+    @SerialName("1")
+    CASE_1,
+
+    @SerialName("2")
+    CASE_2,
+
+    @SerialName("-1")
+    UNKNOWN,
+}
+
+private class TestEnumSerializer : BaseEnumeratedIntSerializer<TestEnum>(
+    className = "TestEnum",
+    values = TestEnum.entries.toTypedArray(),
+    default = TestEnum.UNKNOWN,
+)