课堂使用情况

app/services/subjects/course_used_info_service.rb

@@ -0,0 +1,42 @@
+class Subjects::CourseUsedInfoService < ApplicationService
+  attr_reader :subject, :user
+  def initialize(subject, user)
+    @subject = subject
+    @user = user
+    @shixuns = subject.shixuns
+    @shixun_ids = @shixuns.pluck(:id)
+  end
+
+  def call
+    return if subject.blank?
+    homework_commons =
+        HomeworkCommon.joins(:homework_commons_shixun)
+            .where(homework_type: %i[practice])
+            .where(homework_commons_shixuns: {shixun_id: @shixun_ids})
+    course_ids = homework_commons.pluck(:course_id)
+    homework_common_ids = homework_commons.pluck("homework_commons.id")
+    schools = School.joins(courses: [:course_members, :homework_commons])
+
+    # name：将该课程使用到课堂的单位
+    # course_count: 将该课程使用到课堂的数量
+    # student_count: 课堂的学生总数（去掉重复）
+    # choice_shixun_num: 选用该课程实训的个数（去重）
+    # choice_shixun_frequency: 选用该课程实训的次数
+    course_info =
+        schools.map do |school|
+          name = school.name
+          course_count = school.where(courses: {id: course_ids}).count
+          student_count = school.where(course_members: {role: 4}).select("course_members.user_id").distinct.size
+          homework_commons = school.where(homework_commons: {id: homework_common_ids})
+                                 .select("homework_commons.id")
+          choice_shixun_num = homework_commons.distinct.size
+          choice_shixun_frequency = homework_commons.size
+          {name: name, course_count: course_count, student_count: student_count, choice_shixun_num: choice_shixun_num,
+           choice_shixun_frequency: choice_shixun_frequency}
+        end
+    # 默认按照选用实训的次数作为排序
+    course_info.sort{|x,y| y['choice_shixun_frequency'] <=> x['choice_shixun_frequency']}
+  end
+
+end
+