var mongoose = require('mongoose');
var uniqueValidator = require('mongoose-unique-validator');
var slug = require('slug');

var QcmSchema = new mongoose.Schema({
    name: { type: String, lowercase: true, unique: true },
    slug: { type: String, lowercase: true, unique: true },
    categories: [
        { type: mongoose.Schema.Types.ObjectId, ref: 'QcmCategory' }
    ]
}, {timestamps: true, toJSON: {virtuals: true}});

QcmSchema.plugin(uniqueValidator, { message: 'is already taken' });

QcmSchema.pre('validate', function (next) {
    if (!this.slug) {
        this.slugify();
    }
    next();
});

QcmSchema.methods.slugify = function () {
this.slug = slug(`${this.name}-`) + (Math.random() * Math.pow(36, 6) | 0).toString(36);
};

QcmSchema.methods.addCategory = function (id) {
    if (this.categories.indexOf(id) === -1) {
        this.categories.push(id);
    }
    return this.save();
};

QcmSchema.methods.removeCategory = function (id) {
    this.categories.remove(id);
    return this.save();
};

QcmSchema.methods.toJSONFor = function() {
    return {
        name: this.name,
        slug: this.slug,
        categories: this.categories.map(category => category.toJSONFor())
    };
};

mongoose.model('Qcm', QcmSchema);