const mongoose = require('../mongoose');
const uuid = require('uuid');
const Schema = mongoose.Schema;

const AssetSchema = new Schema({
  id: {
    type: String,
    default: uuid.v4,
    unique: true,
    index: true
  },
  url: {
    type: String,
    unique: true,
    index: true
  },
  type: {
    type: String,
    default: 'article'
  },
  scraped: {
    type: Date,
    default: null
  },
  title: String,
  description: String,
  image: String,
  section: String,
  subsection: String,
  author: String,
  publication_date: Date,
  modified_date: Date
}, {
  versionKey: false,
  timestamps: {
    createdAt: 'created_at',
    updatedAt: 'updated_at'
  }
});

/**
 * Search for assets. Currently only returns all.
*/
AssetSchema.statics.search = (query) => Asset.find(query);

/**
 * Finds an asset by its id.
 * @param {String} id  identifier of the asset (uuid).
*/
AssetSchema.statics.findById = (id) => Asset.findOne({id});

/**
 * Finds a asset by its url.
 * @param {String} url  identifier of the asset (uuid).
*/
AssetSchema.statics.findByUrl = (url) => Asset.findOne({url});

/**
 * Finds a asset by its url.
 *
 * NOTE: This function has scalability concerns regarding mongoose's decision
 * always write {updated_at: new Date()} on every call to findOneAndUpdate
 * even though the update document exactly matches the query document... In
 * the future this function should never update, only findOneAndCreate but this
 * is not possible with the mongoose driver.
 *
 * @param {String} url  identifier of the asset (uuid).
*/
AssetSchema.statics.findOrCreateByUrl = (url) => Asset.findOneAndUpdate({url}, {url}, {

  // Ensure that if it's new, we return the new object created.
  new: true,

  // Perform an upsert in the event that this doesn't exist.
  upsert: true,

  // Set the default values if not provided based on the mongoose models.
  setDefaultsOnInsert: true
});

const Asset = mongoose.model('Asset', AssetSchema);

module.exports = Asset;