/**
 * Key/value store
 *
 *  Copyright (C) 2017 R-T Specialty, LLC.
 *
 *  This file is part of liza.
 *
 *  liza is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

var Class        = require( 'easejs' ).Class,
    Bucket       = require( './Bucket' ),
    EventEmitter = require( 'events' ).EventEmitter;

/**
 * General key/value store for document
 *
 * The term "Quote" here is an artifact from the initial design of the
 * system used for insurance quoting.  It will be renamed.
 *
 * @todo Rename to DocumentDataBucket
 */
module.exports = Class( 'QuoteDataBucket' )
    .implement( Bucket )
    .extend( EventEmitter,
{
    /**
     * Triggered when data in the bucket is updated, before it's committed
     * @type {string}
     */
    'const EVENT_UPDATE': 'update',


    /**
     * Raw key/value store
     * @type {Object}
     */
    'private _data': {},


    /**
     * Cleans a name for use in the bucket
     *
     * Removes trailing brackets, if present
     *
     * @return {string} cleaned name
     */
    'private _cleanName': function( name )
    {
        name = ''+name || '';

        var bracket = name.indexOf( '[' );
        if ( bracket == -1 )
        {
            return name;
        }

        return name.substring( 0, bracket );
    },


    /**
     * Explicitly sets the contents of the bucket
     *
     * @param {Object.<string,Array>} data associative array of the data
     *
     * @return {QuoteDataBucket} self to allow for method chaining
     */
    'public setValues': function( data )
    {
        this._mergeData( data );
        return this;
    },


    /**
     * Alias of setValues
     *
     * @return {QuoteDataBucket} self to allow for method chaining
     */
    'public setCommittedValues': function()
    {
        return this.setValues.apply( this, arguments );
    },


    /**
     * Clears all data from the bucket
     *
     * @return {QuoteDataBucket} self
     */
    'public clear': function()
    {
        this._data = {};
        return this;
    },


    /**
     * Merges updated data with the existing data
     *
     * @param Object data updated data
     *
     * @return undefined
     */
    'private _mergeData': function( data )
    {
        var ignore = {};

        // remove any data that has not been updated (the hooks do processing on
        // this data, often updating the DOM, so it's faster to do this than to
        // have a lot of unnecessary DOM work done)
        for ( name in data )
        {
            var data_set = data[ name ],
                pre_set  = this._data[ name ],
                changed  = false;

            // if there's no previous data for this key, or the lengths vary,
            // then we want to keep it
            if ( ( pre_set === undefined )
                || ( pre_set.length !== data_set.length )
            )
            {
                continue;
            }

            for ( var i = 0, len = data_set.length; i < len; i++ )
            {
                if ( data_set[ i ] !== pre_set[ i ] )
                {
                    changed = true;
                    break;
                }
            }

            // data matches original---we do not want to delete it, since that
            // would modify the provided object; instead, mark it to be ignored
            if ( changed === false )
            {
                ignore[ name ] = true;
            }
        }

        this.emit( this.__self.$('EVENT_UPDATE'), data );

        for ( name in data )
        {
            if ( ignore[ name ] )
            {
                continue;
            }

            var data_set = data[ name ];

            // initialize it if its undefined in the bucket
            if ( this._data[name] === undefined )
            {
                this._data[name] = [];
            }

            // merge the indexes one by one to preserve existing data
            var data_set_len = data_set.length;
            for ( var i = 0; i < data_set_len; i++ )
            {
                // ignore undefined (since we're merging, if it's not set, then
                // we don't want to remove the data that's already there)
                if ( data_set[ i ] === undefined )
                {
                    continue;
                }

                // ignore if set to null (implying the index was removed)
                if ( data_set[i] === null )
                {
                    // this marks the end of the array as far as we're concerned
                    this._data[ name ].length = i;
                    break;
                }

                this._data[name][i] = data_set[i];
            }
        }
    },


    /**
     * Overwrites values in the original bucket
     *
     * For this buckeet, overwriteValues() is an alias for setValues() without
     * index merging. However, other Bucket implementations may handle it
     * differently.
     *
     * @param {Object.<string,Array>} data associative array of the data
     *
     * @return {Bucket} self
     */
    'public overwriteValues': function( data )
    {
        this.setValues(
            Object.keys( data ).reduce(
                ( vals, key ) => (
                    vals[ key ] = data[ key ].concat( [ null ] ),
                    vals
                ),
                {}
            )
        );

        return this;
    },


    /**
     * Calls a function for each each of the values in the bucket
     *
     * Note: This format is intended to be consistent with Array.forEach()
     *
     * @param {function(string,string)} callback function to call for each
     *                                           value in the bucket
     *
     * @return {QuoteDataBucket} self to allow for method chaining
     */
    'public each': function( callback )
    {
        var bucket = this;

        for ( var name in this._data )
        {
            callback( this._data[ name ], name );
        }

        return this;
    },


    /**
     * Calls a function for each each of the values in the bucket matching the
     * given predicate
     *
     * @param {function(string)}           pred predicate
     * @param {function( Object, number )} c    function to call for each
     *                                          value in the bucket
     *
     * @return {StagingBucket} self
     */
    'public filter': function( pred, c )
    {
        this.each( function( data, name )
        {
            if ( pred( name ) )
            {
                c( data, name );
            }
        } );
    },


    /**
     * Returns the data for the requested field
     *
     * @param {string} name name of the field (with or without trailing brackets)
     *
     * @return {Array} data for the field, or empty array if none
     */
    'public getDataByName': function( name )
    {
        var data = this._data[ this._cleanName( name ) ];

        if ( data === undefined )
        {
            return [];
        }

        if ( data === null )
        {
            return null;
        }

        // return a copy of the data
        return ( typeof data === 'object' ) ? data.slice( 0 ) : data;
    },


    /**
     * Returns the data as a JSON string
     *
     * @return {string} data represented as JSON
     */
    'public getDataJson': function()
    {
        return JSON.stringify( this._data );
    },


    /**
     * Return raw bucket data
     *
     * TODO: remove; breaks encapsulation
     *
     * @return {Object} raw bucket data
     */
    'public getData': function()
    {
        return this._data;
    }
} );