<?php

/*
Copyright 2016-2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.

Licensed under the GNU General Public License as published by the Free Software Foundation,
Version 2.0 (the "License"). You may not use this file except in compliance with the License.
A copy of the License is located in the "license" file accompanying this file.

This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
either express or implied. See the License for the specific language governing permissions
and limitations under the License.
*/

namespace AmazonAssociatesLinkBuilder\rendering;

use AmazonAssociatesLinkBuilder\constants\Paapi_Constants;
use AmazonAssociatesLinkBuilder\helper\Xml_Helper;
use AmazonAssociatesLinkBuilder\constants\XML_Constants;

/**
 * Helper class for customizations to the xml response
 *
 * @since      1.8.0
 * @package    AmazonAssociatesLinkBuilder
 * @subpackage AmazonAssociatesLinkBuilder/lib/php
 */
class Xml_Manipulator {
    private $xml_helper;

    public function __construct( Xml_Helper $xml_helper ) {
        $this->xml_helper = $xml_helper;
    }

    /**
     * Returns the Customized Items SimpleXML Object which contains Aalb Node and
     * some other customized values as per business logic.
     *
     * @since 1.8.0
     *
     * @param string $products_xml Well-formed XML string of Products
     * @param string $marketplace
     *
     * @return \SimpleXMLElement Php xml object.
     */
    public function get_customized_items_object( $products_xml, $marketplace ) {
        $simple_xml_object = $this->parse( $products_xml );
        $custom_items = $this->add_custom_nodes( $simple_xml_object->Items, $marketplace );

        return $custom_items;
    }

    /**
     * Convert the well-formed xml string into a SimpleXMLElement object and check if the object is formed successfully.
     *
     * @since 1.0.0
     *
     * @param string $xml_string Well-formed XML string
     *
     * @throws \Exception if xml element object was nt formed successfully
     *
     * @return \SimpleXMLElement Php xml object.
     */
    public function parse( $xml_string ) {
        libxml_use_internal_errors( true );
        $xml = simplexml_load_string( $xml_string );
        if ( $xml === false ) {
            //Don't translate as this is also dumped in error logs and will facilitate AALB team to debug
            throw new \Exception( 'Xml_Manipulator::validate::Failed Loading XML' );
        }

        return $xml;
    }

    /**
     * Add custom nodes to xml response
     *
     * @since 1.8.0
     *
     * @param \SimpleXMLElement $xml Well-formed XML string
     * @param string $marketplace     Marketplace
     *
     * @return \SimpleXMLElement $items XML String with custom nodes added
     */
    private function add_custom_nodes( $items, $marketplace ) {
        $common_marketplace_node_name = 'Marketplace' . $marketplace;

        foreach ( $items->Item as $item ) {
            $this->decorate_item( $item, $marketplace, $common_marketplace_node_name );
        }

        return $items;
    }

    /**
     * Add common nodes to xml response
     *
     * @since 1.8.0
     *
     * @param \SimpleXMLElement $items Well-formed XML string
     * @param string $marketplace Marketplace
     *
     * @return \SimpleXMLElement $items XML String with custom nodes added
     */
    private function add_common_nodes( $products_xml, $marketplace ) {
        $xml_response = $this->parse( $products_xml );
        $items = $xml_response->Items;

        $common_marketplace_node_name = 'Marketplace' . $marketplace;
        $items->ID = "[[UNIQUE_ID]]";
        $basic_labels = $this->xml_helper->get_basic_labels( $marketplace );
        $items->PriceLabel = $basic_labels[XML_Constants::PRICE_LABEL];
        $items->StrikePriceLabel = $basic_labels[XML_Constants::STRIKE_PRICE_LABEL];
        $items->ProductsFromAmazonLabel = $basic_labels[XML_Constants::PRODUCTS_FROM_AMAZON_LABEL];
        $aalb_header_node = $items->addChild( 'AalbHeader' );
        $aalb_header_node->$common_marketplace_node_name = 'true';

        return $items;
    }

    /**
     * Get customized response which contains attributes common to all items
     *
     * @since 1.8.0
     *
     * @param string $items_xml String of final response
     * @param string $store_id Store_id
     * @param string $link_code Link code
     * @param string $marketplace Marketplace
     *
     * @return \SimpleXMLElement
     */
    public function get_customized_response( $items_xml, $store_id, $link_code, $marketplace ){
        return $this->add_common_nodes( $this->modify_xml( $items_xml, $store_id, $link_code ), $marketplace );
    }

    /**
     * Add the Information for the Item(which is calculated based on business logic) to the Aalb node.
     *
     * @since 1.8.0
     *
     * @param \SimpleXMLElement $item
     * @param String $marketplace
     *
     */
    private function decorate_item( $item, $marketplace, $common_marketplace_node_name ) {
        $basic_info = $this->xml_helper->get_basic_info( $item );
        $image_urls = $this->xml_helper->get_image_urls( $item );
        $price_related_info = $this->xml_helper->get_price_related_information( $item, $marketplace );
        $savings_info = $price_related_info[XML_Constants::SAVINGS_INFO];
        $min_price_info = $price_related_info[XML_Constants::MIN_PRICE_INFO];

        $nodes = array(
            XML_Constants::ASIN                => $basic_info[XML_Constants::ASIN],
            XML_Constants::TITLE               => $basic_info[XML_Constants::TITLE],
            XML_Constants::DETAIL_PAGE_URL     => $basic_info[XML_Constants::DETAIL_PAGE_URL],
            XML_Constants::LARGE_IMAGE_URL     => $image_urls[XML_Constants::LARGE_IMAGE_URL],
            XML_Constants::MEDIUM_IMAGE_URL    => $image_urls[XML_Constants::MEDIUM_IMAGE_URL],
            XML_Constants::SMALL_IMAGE_URL     => $image_urls[XML_Constants::SMALL_IMAGE_URL],
            XML_Constants::BY                  => $this->xml_helper->get_by_information( $item ),
            XML_Constants::PRIME               => $this->xml_helper->get_prime_eligibility( $item ),
            XML_Constants::MERCHANT            => $this->xml_helper->get_merchant_name( $item ),
            XML_Constants::SAVING              => $savings_info[XML_Constants::SAVING],
            XML_Constants::SAVING_VALUE        => $savings_info[XML_Constants::SAVING_VALUE],
            XML_Constants::SAVING_PERCENT      => $savings_info[XML_Constants::SAVING_PERCENT],
            XML_Constants::MINIMUM_PRICE       => $min_price_info[XML_Constants::MINIMUM_PRICE],
            XML_Constants::MINIMUM_PRICE_VALUE => $min_price_info[XML_Constants::MINIMUM_PRICE_VALUE],
            XML_Constants::CURRENT_PRICE       => $price_related_info[XML_Constants::CURRENT_PRICE],
            XML_Constants::CURRENT_PRICE_VALUE => $price_related_info[XML_Constants::CURRENT_PRICE_VALUE],
            XML_Constants::STRIKE_PRICE        => $price_related_info[XML_Constants::STRIKE_PRICE],
            XML_Constants::STRIKE_PRICE_VALUE  => $price_related_info[XML_Constants::STRIKE_PRICE_VALUE],
            XML_Constants::IN_STOCK            => $price_related_info[XML_Constants::IN_STOCK],
            $common_marketplace_node_name      => 'true'
        );

        $aalb_node = $item->addChild( 'aalb' );
        foreach ( $nodes as $key => $value ) {
            if ( ! empty( $value ) ) {
                $aalb_node->$key = $value;
            }
        }

        //Below is done as earlier we were maintaining current price value node even if value is null
        $aalb_node->CurrentPriceValue = $price_related_info[XML_Constants::CURRENT_PRICE_VALUE];
    }

    /**
     * Change the store_id before rendering the response.
     *
     * @since 1.8.0
     *
     * @param string $response Item lookup response stored in table which may have a different store_id.
     * @param string $store_id The replacement for store_id in response.
     *
     * @return string           Modified response.
     */
    public function modify_xml( $response, $store_id, $link_code ) {
        //use wordpress linkcode
        $response = preg_replace( "/linkCode(%3D|=)\w{1,3}/", "linkCode$1" . $link_code, $response );

        //replace store id
        return preg_replace( "((tag=)[^&]+(&))", "$1" . $store_id . "$2", $response );
    }

    /**
     * Single Escape Numeric Character References(NCR) using regular expression replacement
     *
     * @since 1.8.0
     *
     * @param string $products Deserialized XML string with NCRs double escaped
     *
     * @return string Deserialized XML string with NCRS single escaped
     */
    public function unescape_numeric_character_references( $products ) {
        //Single Escape NCR represented as hex number
        $products = preg_replace( "/&amp;(#x[a-fA-F0-9]{4,6};)/", "&$1", $products );

        //Single Escape other special characters escaped by Product Advertising API like Σ(&#931;),Θ(&#920;)
        $products = preg_replace( "/&amp;(#[0-9]{1,7};)/", "&$1", $products );

        return $products;
    }

}