fix: merge message by role to generate correctly with deepseek

Author: Stream29

src/main/kotlin/io/github/stream29/proxy/client/MergeMessage.kt

@@ -1,5 +1,11 @@
 package io.github.stream29.proxy.client
 
+import io.github.stream29.proxy.server.LChatCompletionRequest
+import io.github.stream29.proxy.server.LChatCompletionResponseChunk
+import io.github.stream29.proxy.server.OChatRequest
+import io.github.stream29.proxy.server.OChatResponseChunk
+import kotlinx.coroutines.flow.Flow
+
 fun <T> List<T>.mergeBy(
     selector: (T) -> String,
     merger: (T, T) -> T,
@@ -9,12 +15,38 @@ fun <T> List<T>.mergeBy(
     for (item in this) {
         result.add(
             if (lastItem != null && selector(lastItem) == selector(item)) {
-                merger(lastItem, item).also { lastItem = it }
+                merger(lastItem, item).also { result.removeAt(result.lastIndex) }
             } else {
-                lastItem = item
                 item
-            }
+            }.also { lastItem = it }
         )
     }
     return result
+}
+
+fun ApiProvider.messageMergedByRole() = MessageMergedApiProvider(this)
+class MessageMergedApiProvider(
+    val delegate: ApiProvider,
+) : ApiProvider by delegate {
+    override suspend fun generateLStream(request: LChatCompletionRequest): Flow<LChatCompletionResponseChunk> {
+        return delegate.generateLStream(
+            request.copy(
+                messages = request.messages.mergeBy(
+                    selector = { it.role },
+                    merger = { a, b -> a.copy(content = a.content + b.content) }
+                )
+            )
+        )
+    }
+
+    override suspend fun generateOStream(request: OChatRequest): Flow<OChatResponseChunk> {
+        return delegate.generateOStream(
+            request.copy(
+                messages = request.messages.mergeBy(
+                    selector = { it.role },
+                    merger = { a, b -> a.copy(content = a.content + b.content) }
+                )
+            )
+        )
+    }
 }

src/main/kotlin/io/github/stream29/proxy/client/OpenAiBased.kt

@@ -23,42 +23,11 @@ data class DashScopeConfig(
 data class DeepSeekConfig(
     val apiKey: String,
     val modelList: List<String> = listOf("deepseek-chat", "deepseek-reasoner"),
-) : ApiProvider {
-    val delegate = OpenAiConfig(
-        baseUrl = "https://api.deepseek.com/",
-        apiKey = apiKey,
-        modelList = modelList
-    )
-
-    override suspend fun getModelNameList(): List<String> = modelList
-
-    override suspend fun generateLStream(request: LChatCompletionRequest): Flow<LChatCompletionResponseChunk> {
-        return delegate.generateLStream(
-            request.copy(
-                messages = request.messages.mergeBy(
-                    selector = { it.role },
-                    merger = { a, b -> a.copy(content = a.content + b.content) }
-                )
-            )
-        )
-    }
-
-    override suspend fun generateOStream(request: OChatRequest): Flow<OChatResponseChunk> {
-        return delegate.generateOStream(
-            request.copy(
-                messages = request.messages.mergeBy(
-                    selector = { it.role },
-                    merger = { a, b -> a.copy(content = a.content + b.content) }
-                )
-            )
-        )
-    }
-
-    override fun close() {
-        delegate.close()
-    }
-
-}
+) : ApiProvider by OpenAiConfig(
+    baseUrl = "https://api.deepseek.com/",
+    apiKey = apiKey,
+    modelList = modelList
+).messageMergedByRole()
 
 @Suppress("unused")
 @Serializable