feat(报告)：AI 聚合残片生成报告草稿

- AiServiceClient：调用 lpt-ai 独立服务，未配置/失败时返回 empty
- GET /study-sessions/{sessionNum}/report-draft：AI 聚合（含预期对比），降级为残片拼接
- 草稿仅作为编辑起点，最终报告仍由用户确认后保存
- application.yml 增加 lpt.ai-service.url 配置

src/main/java/com/guo/learningprogresstracker/controller/StudySessionController.java

@@ -99,4 +99,12 @@ public class StudySessionController {
         return CommonResult.success(allFragments);
 
     }
+
+    /**
+     * 生成学习报告草稿：AI 聚合残片（不可用时降级为拼接），返回给前端作为编辑起点
+     */
+    @GetMapping("/{sessionNum}/report-draft")
+    public CommonResult<String> getReportDraft(@PathVariable("sessionNum") String sessionNum) throws ErrorParameterException {
+        return CommonResult.success("请求成功", studySessionsServiceImpl.generateReportDraft(sessionNum));
+    }
 }

src/main/java/com/guo/learningprogresstracker/service/impl/AiServiceClient.java

@@ -0,0 +1,92 @@
+package com.guo.learningprogresstracker.service.impl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.annotation.PostConstruct;
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.stereotype.Component;
+
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+/**
+ * lpt-ai 独立 AI 服务客户端。
+ * <p>通过 {@code lpt.ai-service.url} 配置服务地址；未配置或调用失败时返回 empty，由调用方降级。</p>
+ */
+@Slf4j
+@Component
+@ConfigurationProperties(prefix = "lpt.ai-service")
+@Setter
+public class AiServiceClient {
+
+    /** lpt-ai 服务地址，如 http://localhost:5199 */
+    private String url;
+    /** 超时秒数 */
+    private int timeoutSeconds = 90;
+
+    private HttpClient httpClient;
+    private final ObjectMapper objectMapper = new ObjectMapper();
+
+    @PostConstruct
+    void init() {
+        httpClient = HttpClient.newBuilder()
+                .connectTimeout(Duration.ofSeconds(10))
+                .build();
+        if (isConfigured()) {
+            log.info("AiServiceClient 已配置: {}", url);
+        } else {
+            log.info("AiServiceClient 未配置，AI 聚合功能不可用（将降级为拼接）");
+        }
+    }
+
+    public boolean isConfigured() {
+        return url != null && !url.isBlank();
+    }
+
+    /**
+     * 调用 lpt-ai 将残片聚合为学习报告草稿。
+     *
+     * @return 聚合后的报告文本；服务未配置或调用失败时返回 empty
+     */
+    public Optional<String> aggregateReport(String taskName, List<String> fragments, String expectation) {
+        if (!isConfigured() || fragments == null || fragments.isEmpty()) {
+            return Optional.empty();
+        }
+        try {
+            List<Map<String, String>> fragmentBodies = fragments.stream()
+                    .map(content -> Map.of("content", content))
+                    .toList();
+            Map<String, Object> body = expectation == null || expectation.isBlank()
+                    ? Map.of("taskName", taskName, "fragments", fragmentBodies)
+                    : Map.of("taskName", taskName, "fragments", fragmentBodies, "expectation", expectation);
+
+            HttpRequest request = HttpRequest.newBuilder()
+                    .uri(URI.create(url + "/ai/aggregate-report"))
+                    .timeout(Duration.ofSeconds(timeoutSeconds))
+                    .header("Content-Type", "application/json")
+                    .POST(HttpRequest.BodyPublishers.ofString(objectMapper.writeValueAsString(body)))
+                    .build();
+
+            HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+            if (response.statusCode() != 200) {
+                log.warn("lpt-ai 聚合报告失败: status={}, body={}", response.statusCode(),
+                        response.body() != null ? response.body().substring(0, Math.min(200, response.body().length())) : "");
+                return Optional.empty();
+            }
+            JsonNode json = objectMapper.readTree(response.body());
+            String report = json.path("report").asText(null);
+            return Optional.ofNullable(report).filter(s -> !s.isBlank());
+        } catch (Exception e) {
+            log.warn("lpt-ai 调用异常，将降级: {}", e.getMessage());
+            return Optional.empty();
+        }
+    }
+}

src/main/java/com/guo/learningprogresstracker/service/impl/StudySessionsServiceImpl.java

@@ -16,6 +16,7 @@ import com.guo.learningprogresstracker.mapStruct.StudySessionConvert;
 import com.guo.learningprogresstracker.mapper.StudyReportFragmentsMapper;
 import com.guo.learningprogresstracker.mapper.StudyReportsMapper;
 import com.guo.learningprogresstracker.mapper.StudySessionsMapper;
+import com.guo.learningprogresstracker.service.StudyExpectationsService;
 import com.guo.learningprogresstracker.service.StudySessionsService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -41,6 +42,8 @@ public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, S
     private final StudyReportFragmentsServiceImpl studyReportFragmentsServiceImpl;
     private final StudyReportFragmentsMapper studyReportFragmentsMapper;
     private final StudyReportsMapper studyReportsMapper;
+    private final AiServiceClient aiServiceClient;
+    private final StudyExpectationsService studyExpectationsService;
 
     public StudySessionResponse startOrContinueStudySession(String taskNum) throws NotFindEntitiesException, ServiceException {
         TaskEntity taskEntity = tasksServiceImpl.getOneOpt(
@@ -158,4 +161,30 @@ public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, S
         return StudySessionConvert.MAPPER.toStudySessionResponse(session);
     }
 
+    /**
+     * 生成学习报告草稿：优先调用 lpt-ai 聚合残片，服务不可用时降级为按序拼接。
+     * 草稿仅作为编辑起点返回，不落库——最终报告由用户确认后经 endedStudySession 保存。
+     */
+    public String generateReportDraft(String sessionNum) throws ErrorParameterException {
+        StudySessionsEntity session = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
+                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
+                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
+
+        ArrayList<String> fragments = getAllFragments(sessionNum);
+        if (fragments.isEmpty()) {
+            return "";
+        }
+
+        String taskName = tasksServiceImpl.getOneOpt(
+                        Wrappers.lambdaQuery(TaskEntity.class).eq(TaskEntity::getTaskNum, session.getTaskNum()))
+                .map(TaskEntity::getTaskName)
+                .orElse("学习任务");
+        String expectation = Optional.ofNullable(studyExpectationsService.getBySessionNum(sessionNum))
+                .map(e -> e.getDescription())
+                .orElse(null);
+
+        return aiServiceClient.aggregateReport(taskName, fragments, expectation)
+                .orElseGet(() -> String.join("\n", fragments));
+    }
+
 }

src/main/resources/application.yml

@@ -59,3 +59,7 @@ lpt:
         api-key:
         model: claude-fable-5
         timeout-seconds: 60
+    # lpt-ai 独立服务地址（可选，未配置时报告草稿降级为残片拼接）
+    ai-service:
+        url:
+        timeout-seconds: 90