models/Course.js

const mongoose = require('mongoose');

const courseSchema = new mongoose.Schema({
  title: {
    type: String,
    required: [true, 'Please add a course title'],
    trim: true
  },
  description: {
    type: String,
    required: [true, 'Please add a description']
  },
  category: {
    type: String,
    required: [true, 'Please add a category']
  },
  duration: {
    type: Number,
    required: [true, 'Please add course duration in weeks']
  },
  instructor: {
    type: mongoose.Schema.ObjectId,
    ref: 'User',
    required: true
  },
  price: {
    type: Number,
    required: [true, 'Please add a price']
  },
  image: {
    type: String,
    default: 'default-course.jpg'
  },
  isFeatured: {
    type: Boolean,
    default: false
  },
  status: {
    type: String,
    enum: ['draft', 'published', 'archived'],
    default: 'draft'
  },
  createdAt: {
    type: Date,
    default: Date.now
  }
}, {
  toJSON: { virtuals: true },
  toObject: { virtuals: true }
});

// Reverse populate with enrollments
courseSchema.virtual('enrollments', {
  ref: 'Enrollment',
  localField: '_id',
  foreignField: 'course',
  justOne: false
});

module.exports = mongoose.model('Course', courseSchema);