From 4ec61e48cada70cd7fc4f26ab2fcb9a726b0c241 Mon Sep 17 00:00:00 2001
From: En <huangmingen@lesingle.com>
Date: Fri, 20 Mar 2026 14:36:12 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E8=AF=BE=E7=A8=8B=E5=8C=85=E7=BB=9F?=
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1. CoursePackageMapper: 新增 decrementUsageCount 方法
   - 课程取消时减少使用次数

2. LessonServiceImpl: 完善课程状态变更时的统计
   - cancelLesson: 取消时 usage_count -1
   - startLesson: 设置 startDatetime
   - completeLesson: 完成时设置 endDatetime

统计口径：
- usage_count: status != 'cancelled' 的课程数（创建时 +1，取消时 -1）
- teacher_count: status = 'completed' 的课程中去重教师数
---
 .../com/reading/platform/mapper/CoursePackageMapper.java  | 7 +++++++
 .../reading/platform/service/impl/LessonServiceImpl.java  | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/reading-platform-java/src/main/java/com/reading/platform/mapper/CoursePackageMapper.java b/reading-platform-java/src/main/java/com/reading/platform/mapper/CoursePackageMapper.java
index 8c4329d..84dbc51 100644
--- a/reading-platform-java/src/main/java/com/reading/platform/mapper/CoursePackageMapper.java
+++ b/reading-platform-java/src/main/java/com/reading/platform/mapper/CoursePackageMapper.java
@@ -16,6 +16,13 @@ public interface CoursePackageMapper extends BaseMapper<CoursePackage> {
     @Update("UPDATE course_package SET usage_count = usage_count + 1 WHERE id = #{coursePackageId}")
     void incrementUsageCount(@Param("coursePackageId") Long coursePackageId);
 
+    /**
+     * 减少课程包使用次数（课程取消时调用）
+     * @param coursePackageId 课程包 ID
+     */
+    @Update("UPDATE course_package SET usage_count = GREATEST(usage_count - 1, 0) WHERE id = #{coursePackageId}")
+    void decrementUsageCount(@Param("coursePackageId") Long coursePackageId);
+
     /**
      * 更新课程包教师数量（去重统计已完成课程的教师）
      * @param coursePackageId 课程包 ID
diff --git a/reading-platform-java/src/main/java/com/reading/platform/service/impl/LessonServiceImpl.java b/reading-platform-java/src/main/java/com/reading/platform/service/impl/LessonServiceImpl.java
index 0403635..0fdc016 100644
--- a/reading-platform-java/src/main/java/com/reading/platform/service/impl/LessonServiceImpl.java
+++ b/reading-platform-java/src/main/java/com/reading/platform/service/impl/LessonServiceImpl.java
@@ -174,6 +174,7 @@ public class LessonServiceImpl extends ServiceImpl<LessonMapper, Lesson>
     public void startLesson(Long id) {
         Lesson lesson = getLessonById(id);
         lesson.setStatus(LessonStatus.IN_PROGRESS.getCode());
+        lesson.setStartDatetime(LocalDateTime.now());
         lessonMapper.updateById(lesson);
         log.info("课程开始：id={}", id);
     }
@@ -183,6 +184,7 @@ public class LessonServiceImpl extends ServiceImpl<LessonMapper, Lesson>
     public void completeLesson(Long id) {
         Lesson lesson = getLessonById(id);
         lesson.setStatus(LessonStatus.COMPLETED.getCode());
+        lesson.setEndDatetime(LocalDateTime.now());
         lessonMapper.updateById(lesson);
         log.info("课程完成：id={}", id);
 
@@ -200,6 +202,12 @@ public class LessonServiceImpl extends ServiceImpl<LessonMapper, Lesson>
         lesson.setStatus(LessonStatus.CANCELLED.getCode());
         lessonMapper.updateById(lesson);
         log.info("课程取消：id={}", id);
+
+        // 更新课程包统计：使用次数 -1（取消的课程不计入使用）
+        if (lesson.getCourseId() != null) {
+            coursePackageMapper.decrementUsageCount(lesson.getCourseId());
+            log.info("课程包使用次数 -1: courseId={}", lesson.getCourseId());
+        }
     }
 
     @Override