From a50e054aca084cae9a0188ae43f4f441d72b6bbb Mon Sep 17 00:00:00 2001
From: Ryan Andriamahery <ryan@hei.school>
Date: Tue, 15 Jul 2025 11:22:14 +0300
Subject: [PATCH] chore: use langchain4j.ChatModel to integrate OpenAi

---
 .../java/school/hei/hazavao/model/Chat.java   | 63 +------------------
 .../school/hei/hazavao/model/OpenAiChat.java  | 28 +++++++++
 .../java/school/hei/hazavao/conf/EnvConf.java |  2 +-
 3 files changed, 30 insertions(+), 63 deletions(-)
 create mode 100644 src/main/java/school/hei/hazavao/model/OpenAiChat.java

diff --git a/src/main/java/school/hei/hazavao/model/Chat.java b/src/main/java/school/hei/hazavao/model/Chat.java
index 8d0dba5..f5a6fcc 100644
--- a/src/main/java/school/hei/hazavao/model/Chat.java
+++ b/src/main/java/school/hei/hazavao/model/Chat.java
@@ -1,66 +1,5 @@
 package school.hei.hazavao.model;
 
-import static java.net.http.HttpClient.newHttpClient;
-
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import java.io.IOException;
-import java.net.URI;
-import java.net.http.HttpRequest;
-import java.net.http.HttpResponse;
 import java.util.function.Function;
-import org.springframework.beans.factory.annotation.Value;
-import org.springframework.stereotype.Component;
-
-@Component
-public class Chat implements Function<String, String> {
-
-  private static final String OPENAPI_URL = "https://api.openai.com/v1/chat/completions";
-  private final String openapiKey;
-
-  public Chat(@Value("${openapi.key}") String openapiKey) {
-    this.openapiKey = openapiKey;
-  }
-
-  @Override
-  public String apply(String content) {
-    var mapper = new ObjectMapper();
-
-    var request = openapiRequest(content, mapper);
-    HttpResponse<String> response = null;
-    try {
-      response = newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
-    } catch (IOException | InterruptedException e) {
-      throw new RuntimeException(e);
-    }
-
-    JsonNode root = null;
-    try {
-      root = mapper.readTree(response.body());
-    } catch (JsonProcessingException e) {
-      throw new RuntimeException(e);
-    }
-    return root.path("choices").get(0).path("message").path("content").asText();
-  }
-
-  private HttpRequest openapiRequest(String content, ObjectMapper mapper) {
-    var message = mapper.createObjectNode();
-    message.put("role", "user");
-    message.put("content", content);
-    var messages = mapper.createArrayNode();
-    messages.add(message);
-
-    var requestBody = mapper.createObjectNode();
-    requestBody.put("model", "gpt-4o");
-    requestBody.set("messages", messages);
-    requestBody.put("temperature", 0.5);
 
-    return HttpRequest.newBuilder()
-        .uri(URI.create(OPENAPI_URL))
-        .header("Content-Type", "application/json")
-        .header("Authorization", "Bearer " + openapiKey)
-        .POST(HttpRequest.BodyPublishers.ofString(requestBody.toString()))
-        .build();
-  }
-}
+public interface Chat extends Function<String, String> {}
diff --git a/src/main/java/school/hei/hazavao/model/OpenAiChat.java b/src/main/java/school/hei/hazavao/model/OpenAiChat.java
new file mode 100644
index 0000000..c560c84
--- /dev/null
+++ b/src/main/java/school/hei/hazavao/model/OpenAiChat.java
@@ -0,0 +1,28 @@
+package school.hei.hazavao.model;
+
+import static dev.langchain4j.model.openai.OpenAiChatModelName.GPT_4_O;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Component;
+
+@Component
+@Primary
+public class OpenAiChat implements Chat {
+  private final String openAiKey;
+
+  public OpenAiChat(@Value("${openai.key}") String openAiKey) {
+    this.openAiKey = openAiKey;
+  }
+
+  @Override
+  public String apply(String input) {
+    var model =
+        dev.langchain4j.model.openai.OpenAiChatModel.builder()
+            .apiKey(openAiKey)
+            .modelName(GPT_4_O)
+            .build();
+
+    return model.chat(input);
+  }
+}
diff --git a/src/test/java/school/hei/hazavao/conf/EnvConf.java b/src/test/java/school/hei/hazavao/conf/EnvConf.java
index 0862879..117d2f9 100644
--- a/src/test/java/school/hei/hazavao/conf/EnvConf.java
+++ b/src/test/java/school/hei/hazavao/conf/EnvConf.java
@@ -4,6 +4,6 @@
 
 public class EnvConf {
   void configureProperties(DynamicPropertyRegistry registry) {
-    registry.add("openapi.key", () -> "dummy");
+    registry.add("openai.key", () -> "dummy");
   }
 }