server/models/Course.js

const mongoose = require('mongoose');

const lessonSchema = new mongoose.Schema({
  title: { type: String, required: true },
  content: { type: String, required: true },
  videoUrl: String,
  duration: Number, // in minutes
  resources: [{
    title: String,
    url: String
  }],
  quiz: { type: mongoose.Schema.Types.ObjectId, ref: 'Quiz' }
}, { timestamps: true });

const courseSchema = new mongoose.Schema({
  title: { type: String, required: true },
  description: { type: String, required: true },
  instructor: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
  category: { type: String, required: true },
  level: { type: String, enum: ['beginner', 'intermediate', 'advanced'], required: true },
  price: { type: Number, default: 0 },
  thumbnail: { type: String, required: true },
  lessons: [lessonSchema],
  studentsEnrolled: { type: Number, default: 0 },
  rating: { type: Number, default: 0 },
  requirements: [String],
  whatYouWillLearn: [String],
  isFeatured: { type: Boolean, default: false },
  createdAt: { type: Date, default: Date.now }
});

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