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module.exports.getCourseDetailsById = async (req, res, next) => {
  const courseId = req.params.courseId;

  try {
    // Find the course by ID
    const course = await courseCollection.findOne({ _id: new ObjectId(courseId) });

    if (!course) {
      return res.status(404).json({ message: "Course not found" });
    }

    // Find chapters for the course
    const chapters = await chapterCollection.find({ courseId: courseId }).toArray();

    // Count the number of chapters
    const numberOfChapters = chapters.length;

    // Extract unique weekIds and count the number of weeks
    const weekIds = new Set(chapters.map((chapter) => chapter.weekId));
    const numberOfWeeks = weekIds.size;

    // Get the list of students enrolled in the course
    const students = await userCollection.find({
      "courses.courseId": courseId,
    }).toArray();

    const studentCount = students.length;

    // Task type breakdown with task data, completion percentage, and overall percentage
    const taskTypeDetails = chapters.reduce((acc, chapter) => {
      chapter.tasks.forEach((task) => {
        if (!task || !task.participants) return; // Skip null tasks or tasks without participants
        
        // Calculate completion percentage for the individual task
        const participantsCount = task.participants.length;
        const completionPercentage = (participantsCount / studentCount) * 100;

        // Initialize the task type in the accumulator if not already present
        if (!acc[task.taskType]) {
          acc[task.taskType] = {
            tasks: [],
            totalCompletionParticipants: 0,
            taskCount: 0
          };
        }

        // Add task details along with completion percentage
        acc[task.taskType].tasks.push({
          taskId: task.taskId,
          taskName: task.taskName,
          participantsCount,
          completionPercentage,
          ...task // Include all other task details
        });

        // Accumulate the completion percentage and task count
        acc[task.taskType].totalCompletionParticipants += completionPercentage;
        acc[task.taskType].taskCount += 1;
      });
      return acc;
    }, {});

    // Calculate the overall completion percentage for each task type
    Object.keys(taskTypeDetails).forEach(taskType => {
      const taskTypeInfo = taskTypeDetails[taskType];
      taskTypeInfo.overallCompletionPercentage = (taskTypeInfo.totalCompletionParticipants / taskTypeInfo.taskCount).toFixed(2);
    });

    // Calculate the total task count
    const totalTaskCount = Object.values(taskTypeDetails).reduce(
      (sum, { taskCount }) => sum + taskCount,
      0
    );

    // Calculate individual student course completion percentages
    const studentsWithCompletion = students.map(student => {
      let studentTaskCount = 0;

      chapters.forEach(chapter => {
        chapter.tasks.forEach(task => {
          // Ensure the task and its participants are valid before checking
          if (task && task.participants) {
            const participantIds = task.participants.map(p => p.participantId); // Extract participant IDs
            if (participantIds.includes(student._id.toString())) {
              studentTaskCount += 1;
            }
          }
        });
      });

      const studentCompletionPercentage = (studentTaskCount / totalTaskCount) * 100;

      return {
        studentId: student._id,
        studentName: student.name,
        studentCompletionPercentage: Math.round(studentCompletionPercentage),
      };
    });

    // Construct the response
    const courseWithDetails = {
      numberOfChapters,
      numberOfWeeks,
      totalTaskCount,
      studentCount,
      taskTypeDetails, // Include detailed task information with overall completion percentages
      studentsWithCompletion, // Include individual student completion percentages // Include chapters if you still need the full details
    };

    res.status(200).json(courseWithDetails);
  } catch (error) {
    console.error("Error retrieving course details:", error);
    res.status(500).json({ message: "Internal Server Error" });
  }
};