const UserSchema = new mongoose.Schema({
    name: {
        first: String,
        last: String
    },
    // Each user can have multiple roles
    roles: [{
        type: String,
        enum: ['admin', 'instructor', 'teachingAssistant', 'student']
    }]
});

UserSchema.methods.hasRole = function (role) {
    return this.roles.indexOf(role) > -1;
};

const CourseSchema = new mongoose.Schema({
    name: { type: String, required: true },
    code: { type: String, required: true, unique: 1, uppercase: 1 },
    // Instructors teaching this course
    instructors: [{ type: mongoose.Schema.Types.ObjectId, ref: 'User' }],
    // TAs teaching this course
    teachingAssistants: [{ type: mongoose.Schema.Types.ObjectId, ref: 'User' }],
    // Students enrolled in the course
    students: [{ type: mongoose.Schema.Types.ObjectId, ref: 'User' }],
});

exports.getCourses = (req, res) => {
    models.Course.find().sort('code').lean().exec((err, courses) => {
        res.render('admin/pages/courses', {
            bodyClass: 'courses',
            title: 'Courses',
            courses: _.filter(courses,  course => {
                return req.user.hasRole('admin') ||
                    course.instructors.indexOf(req.user.id) !== -1 ||
                    course.teachingAssistants.indexOf(req.user.id) !== -1;
            })
        });
    });
};