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'
  },
  headline: String,
  summary: String,
  section: String,
  subsection: String,
  authors: [String],
  publication_date: Date
}, {
  versionKey: false,
  timestamps: {
    createdAt: 'created_at',
    updatedAt: 'updated_at'
  }
});

/**
 * Search for assets. Currently only returns all.
*/
AssetSchema.statics.search = function(query) {

  return Asset.find(query).exec();

};

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

  return Asset.findOne({id}).exec();

};

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

  return Asset.findOne({'url': url}).exec();

};

/**
 * Upserts an asset.
*/
AssetSchema.statics.upsert = function(data) {

  // If an id is not sent, create one.
  if (typeof data.id === 'undefined') {
    data.id = uuid.v4();
  }

  // Perform the upsert against the id field.
  let updatePromise = Asset.update({id: data.id}, data, {upsert: true}).exec()
    .then(() => {

      // Pull the freshly minted asset out and return.
      return Asset.findById(data.id);

    })
    .catch((err) => {

      console.error('Error upserting asset.', err);
      //return new Promise(); // ??? what do we return on error?

    });

  return updatePromise;

};

/**
 * Remove assets from the db.
 * @param {String} query  bson query to identify assets to be removed.
*/
AssetSchema.statics.removeAll = function(query) {

  return Asset.remove(query).exec();

};

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

module.exports = Asset;