[Developer] #424 add MCP reasoning tab

src/main/java/com/cloudhandson/vpdbackoffice/service/OpenAiCompatibleClient.java

@@ -0,0 +1,114 @@
+package com.cloudhandson.vpdbackoffice.service;
+
+import com.cloudhandson.vpdbackoffice.config.BackofficeProperties;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import java.net.URI;
+import java.time.Duration;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestTemplate;
+
+@Service
+public class OpenAiCompatibleClient {
+
+  private final BackofficeProperties properties;
+  private final ObjectMapper objectMapper;
+  private final RestTemplateBuilder restTemplateBuilder;
+
+  public OpenAiCompatibleClient(
+      BackofficeProperties properties,
+      ObjectMapper objectMapper,
+      RestTemplateBuilder restTemplateBuilder
+  ) {
+    this.properties = properties;
+    this.objectMapper = objectMapper;
+    this.restTemplateBuilder = restTemplateBuilder;
+  }
+
+  public boolean configured() {
+    BackofficeProperties.Ai ai = properties.ai();
+    return ai != null
+        && ai.enabled()
+        && hasText(ai.baseUrl())
+        && hasText(ai.model())
+        && hasText(ai.apiKey());
+  }
+
+  public String chat(String systemPrompt, String userPrompt) {
+    if (!configured()) {
+      throw new AppException("AI 호출 설정이 없습니다.");
+    }
+
+    BackofficeProperties.Ai ai = properties.ai();
+    ObjectNode request = objectMapper.createObjectNode();
+    request.put("model", ai.model());
+    request.put("temperature", 0.1);
+    request.put("max_tokens", 1200);
+    ArrayNode messages = request.putArray("messages");
+    messages.add(message("system", systemPrompt));
+    messages.add(message("user", userPrompt));
+
+    HttpHeaders headers = new HttpHeaders();
+    headers.setContentType(MediaType.APPLICATION_JSON);
+    headers.setBearerAuth(ai.apiKey());
+
+    Duration timeout = ai.timeout() == null ? Duration.ofSeconds(30) : ai.timeout();
+    RestTemplate restTemplate = restTemplateBuilder
+        .setConnectTimeout(timeout)
+        .setReadTimeout(timeout)
+        .build();
+    ResponseEntity<String> response = restTemplate.postForEntity(
+        endpoint(ai.baseUrl()),
+        new HttpEntity<>(request.toString(), headers),
+        String.class
+    );
+    return extractAnswer(response.getBody());
+  }
+
+  private ObjectNode message(String role, String content) {
+    ObjectNode message = objectMapper.createObjectNode();
+    message.put("role", role);
+    message.put("content", content);
+    return message;
+  }
+
+  private URI endpoint(String baseUrl) {
+    String trimmed = baseUrl.trim();
+    if (trimmed.endsWith("/chat/completions")) {
+      return URI.create(trimmed);
+    }
+    String withoutSlash = trimmed.endsWith("/") ? trimmed.substring(0, trimmed.length() - 1) : trimmed;
+    if (withoutSlash.endsWith("/v1")) {
+      return URI.create(withoutSlash + "/chat/completions");
+    }
+    return URI.create(withoutSlash + "/v1/chat/completions");
+  }
+
+  private String extractAnswer(String body) {
+    try {
+      JsonNode root = objectMapper.readTree(body);
+      JsonNode content = root.path("choices").path(0).path("message").path("content");
+      if (content.isTextual() && !content.asText().isBlank()) {
+        return content.asText();
+      }
+      JsonNode outputText = root.path("output_text");
+      if (outputText.isTextual() && !outputText.asText().isBlank()) {
+        return outputText.asText();
+      }
+      return objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(root);
+    } catch (Exception e) {
+      throw new AppException("AI 응답을 해석할 수 없습니다: " + e.getMessage());
+    }
+  }
+
+  private boolean hasText(String value) {
+    return value != null && !value.isBlank();
+  }
+}