// # Base Model
// This is the model from which all other Ghost models extend. The model is based on Bookshelf.Model, and provides
// several basic behaviours such as UUIDs, as well as a set of Data methods for accessing information from the database.
//
// The models are internal to Ghost, only the API and some internal functions such as migration and import/export
// accesses the models directly.

// All other parts of Ghost, including the frontend & admin UI are only allowed to access data via the API.
const moment = require('moment');
const ObjectId = require('bson-objectid');
const schema = require('../../data/schema');

const ghostBookshelf = require('./bookshelf');

// Cache an instance of the base model prototype
const proto = ghostBookshelf.Model.prototype;

// ## ghostBookshelf.Model
// The Base Model which other Ghost objects will inherit from,
// including some convenience functions as static properties on the model.
ghostBookshelf.Model = ghostBookshelf.Model.extend({
    // Bookshelf `hasTimestamps` - handles created_at and updated_at properties
    hasTimestamps: true,

    // https://github.com/bookshelf/bookshelf/commit/a55db61feb8ad5911adb4f8c3b3d2a97a45bd6db
    parsedIdAttribute: function () {
        return false;
    },

    // Ghost ordering handling, allows to order by permitted attributes by default and can be overriden on specific model level
    orderAttributes: function orderAttributes() {
        return Object.keys(schema.tables[this.tableName])
            .map(key => `${this.tableName}.${key}`)
            .filter(key => key.indexOf('@@') === -1);
    },

    // When loading an instance, subclasses can specify default to fetch
    defaultColumnsToFetch: function defaultColumnsToFetch() {
        return [];
    },

    // Bookshelf `initialize` - declare a constructor-like method for model creation
    initialize: function initialize() {
        this.initializeEvents();

        // @NOTE: Please keep here. If we don't initialize the parent, bookshelf-relations won't work.
        proto.initialize.call(this);
    },

    // overridable function for models to format attrs only when saving to db
    formatOnWrite: function formatOnWrite(attrs) {
        return attrs;
    },

    hasDateChanged: function (attr) {
        return moment(this.get(attr)).diff(moment(this.previous(attr))) !== 0;
    },

    /**
     * we auto generate a GUID for each resource
     * no auto increment
     */
    setId: function setId() {
        this.set('id', ObjectId().toHexString());
    },

    wasChanged() {
        /**
         * @NOTE:
         * Not every model & interaction is currently set up to handle "._changed".
         * e.g. we trigger a manual event for "tag.attached", where as "._changed" is undefined.
         *
         * Keep "true" till we are sure that "._changed" is always a thing.
         */
        if (!this._changed) {
            return true;
        }

        if (!Object.keys(this._changed).length) {
            return false;
        }

        return true;
    }
});

// Export ghostBookshelf for use elsewhere
module.exports = ghostBookshelf;