fixes in LinkPreviewOptions

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/types/LinkPreviewOptions.kt

@@ -1,10 +1,14 @@
 package dev.inmo.tgbotapi.types
 
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Required
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 
-@Serializable
+@Serializable(LinkPreviewOptions.Companion::class)
 sealed interface LinkPreviewOptions {
     val isDisabled: Boolean
     val url: String?
@@ -76,4 +80,47 @@ sealed interface LinkPreviewOptions {
         override val preferLargeMedia: Boolean
             get() = false
     }
+
+    @Serializable
+    private data class Surrogate(
+        @Required
+        @SerialName(isDisabledField)
+        val isDisabled: Boolean = true,
+        @SerialName(urlField)
+        val url: String? = null,
+        @SerialName(preferSmallMediaField)
+        val preferSmallMedia: Boolean = false,
+        @SerialName(preferLargeMediaField)
+        val preferLargeMedia: Boolean = false,
+        @SerialName(showAboveTextField)
+        val showAboveText: Boolean = false,
+    ) {
+
+    }
+
+    companion object : KSerializer<LinkPreviewOptions> {
+        override val descriptor: SerialDescriptor
+            get() = Surrogate.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): LinkPreviewOptions {
+            val surrogate = Surrogate.serializer().deserialize(decoder)
+
+            return when {
+                surrogate.isDisabled -> Disabled
+                surrogate.preferLargeMedia -> Large(surrogate.url, surrogate.showAboveText)
+                surrogate.preferSmallMedia -> Small(surrogate.url, surrogate.showAboveText)
+                else -> Medium(surrogate.url, surrogate.showAboveText)
+            }
+        }
+
+        override fun serialize(encoder: Encoder, value: LinkPreviewOptions) {
+            when (value) {
+                is Disabled -> Disabled.serializer().serialize(encoder, value)
+                is Large -> Large.serializer().serialize(encoder, value)
+                is Medium -> Medium.serializer().serialize(encoder, value)
+                is Small -> Small.serializer().serialize(encoder, value)
+            }
+        }
+
+    }
 }