<?php
if ( !defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

/**
 * Google vehicle ads
 *
 * Publishes the imported vehicles as a Google Merchant Center data source (RSS 2.0
 * with the g: namespace) and adds what Google checks on the landing page: structured
 * data with the same price and the feed id as a visible ad number.
 *
 * Specification: https://support.google.com/google-ads/answer/11192663
 */

function mobile_api_google_feed_url() {
	return add_query_arg( 'feed', 'google-vehicle-ads', home_url( '/' ) );
}

// Feed, ad number and structured data stay inactive until the dealer opts in with a store code
function mobile_api_google_is_active() {
	return !empty( get_option( 'mobile_api_google_store_code' ) );
}

add_action( 'init', function() {
	add_feed( 'google-vehicle-ads', 'mobile_api_google_feed_render' );
} );

// WordPress sends unknown feed types as application/octet-stream
add_filter( 'feed_content_type', function( $content_type, $type ) {
	return 'google-vehicle-ads' === $type ? 'application/xml' : $content_type;
}, 10, 2 );

// Registered feeds get redirected to /feed/{name}/, which only resolves after a
// rewrite flush. Keep serving the query string URL instead.
add_filter( 'redirect_canonical', function( $redirect_url ) {
	return is_feed( 'google-vehicle-ads' ) ? false : $redirect_url;
} );

// Normalised vehicle data shared by the feed and the structured data, so both
// always report the same price
function mobile_api_google_get_vehicle( $post_id ) {
	$meta = function( $key ) use ( $post_id ) {
		return maybe_unserialize( get_post_meta( $post_id, 'mobile_api_'.$key, true ) );
	};

	$price     = $meta( 'price' );
	$emissions = $meta( 'emissions' );
	$co2       = function( $cycle, $field ) use ( $emissions ) {
		return ( is_object( $emissions ) && isset( $emissions->$cycle->$field ) ) ? (string) $emissions->$cycle->$field : '';
	};

	// Only imported images, like the vehicle page shows them
	$thumbnail_id      = get_post_thumbnail_id( $post_id );
	$additional_images = array();
	foreach ( mobile_api_get_vehicle_images( $post_id ) as $image_id ) {
		if ( $image_id !== $thumbnail_id )
			$additional_images[] = wp_get_attachment_image_url( $image_id, 'full' );
	}

	$make               = (string) $meta( 'make' );
	$model              = (string) $meta( 'model' );
	$color              = (string) $meta( 'manufacturerColorName' );
	$construction_year  = (string) $meta( 'constructionYear' );
	$first_registration = (string) $meta( 'firstRegistration' ); // yyyyMM

	$first_registered = '';
	if ( preg_match( '/^(\d{4})(\d{2})$/', $first_registration, $parts ) )
		$first_registered = $parts[1].'-'.$parts[2];

	if ( '' === $color )
		$color = (string) mobile_api_translate_data_value( (string) $meta( 'exteriorColor' ) );

	return array(
		'ad_id'                => (string) $meta( 'mobileAdId' ),
		'title'                => get_post_field( 'post_title', $post_id ),
		'description'          => (string) $meta( 'plainTextDescription' ),
		'link'                 => get_permalink( $post_id ),
		'vehicle_class'        => (string) $meta( 'vehicleClass' ),
		'category'             => (string) $meta( 'category' ),
		'brand'                => 'VW' === $make ? 'Volkswagen' : $make,
		// mobile.de often leaves the model empty, e.g. for motorhomes
		'model'                => '' !== $model ? $model : (string) $meta( 'modelDescription' ),
		'condition'            => strtolower( (string) $meta( 'condition' ) ),
		'price'                => ( is_object( $price ) && !empty( $price->consumerPriceGross ) ) ? (string) $price->consumerPriceGross : '',
		'currency'             => ( is_object( $price ) && !empty( $price->currency ) ) ? (string) $price->currency : 'EUR',
		'mileage'              => intval( $meta( 'mileage' ) ),
		'color'                => $color,
		'vin'                  => (string) $meta( 'vin' ),
		'fuel'                 => (string) $meta( 'fuel' ),
		'year'                 => '' !== $construction_year ? $construction_year : substr( $first_registration, 0, 4 ),
		'first_registered'     => $first_registered,
		'weight'               => intval( $meta( 'licensedWeight' ) ),
		'damaged'              => !empty( $meta( 'damageUnrepaired' ) ),
		// The featured image is the local copy of the first mobile.de image
		'image'                => get_the_post_thumbnail_url( $post_id, 'full' ) ?: '',
		'additional_images'    => array_slice( $additional_images, 0, 10 ),
		'co2'                  => $co2( 'combined', 'co2' ),
		'co2_class'            => $co2( 'combined', 'co2Class' ),
		'co2_class_discharged' => $co2( 'discharged', 'co2Class' ),
	);
}

function mobile_api_google_get_product_category( $vehicle ) {
	if ( 'Car' === $vehicle['vehicle_class'] )
		return 916; // Cars, Trucks & Vans

	if ( 'Motorhome' === $vehicle['vehicle_class'] ) {
		if ( 'Caravan' === $vehicle['category'] )
			return 4243; // Travel Trailers

		if ( 'MobileHome' !== $vehicle['category'] ) // Stationary, not for public roads
			return 920; // Recreational Vehicles
	}

	return 0; // Motorbikes and commercial vehicles are not allowed
}

function mobile_api_google_get_engine( $fuel ) {
	if ( '' === $fuel )
		return '';

	$engines = array(
		'PETROL'        => 'gasoline',
		'DIESEL'        => 'diesel',
		'ELECTRICITY'   => 'electric',
		'HYBRID'        => 'hybrid',
		'HYBRID_DIESEL' => 'hybrid',
		'LPG'           => 'lpg',
		'CNG'           => 'natural_gas',
	);

	return $engines[$fuel] ?? 'other';
}

function mobile_api_google_get_feed_item( $post_id, $store_code ) {
	$vehicle  = mobile_api_google_get_vehicle( $post_id );
	$category = mobile_api_google_get_product_category( $vehicle );

	if ( !$category || '' === $vehicle['price'] || '' === $vehicle['image'] || $vehicle['damaged'] )
		return null;

	// Google excludes vehicles that need a special driving licence, in Germany class C1 from 3.5 t
	if ( $vehicle['weight'] > 3500 && !get_option( 'mobile_api_google_include_heavy' ) )
		return null;

	$certifications = array();
	if ( '' !== $vehicle['co2_class'] )
		$certifications[] = array( 'certification_authority' => 'BMWK', 'certification_name' => 'Vehicle_CO2_Class', 'certification_code' => $vehicle['co2_class'] );
	if ( '' !== $vehicle['co2_class_discharged'] )
		$certifications[] = array( 'certification_authority' => 'BMWK', 'certification_name' => 'Vehicle_CO2_Class_Discharged_Battery', 'certification_code' => $vehicle['co2_class_discharged'] );

	$item = array(
		'id'                      => $vehicle['ad_id'],
		'title'                   => $vehicle['title'],
		'description'             => mb_substr( trim( preg_replace( '/\s+/', ' ', wp_strip_all_tags( $vehicle['description'] ) ) ), 0, 5000 ),
		'link'                    => $vehicle['link'],
		// {store_code} is a literal placeholder that Google fills in
		'link_template'           => $vehicle['link'].( str_contains( $vehicle['link'], '?' ) ? '&' : '?' ).'store={store_code}',
		'image_link'              => $vehicle['image'],
		'additional_image_link'   => $vehicle['additional_images'],
		'google_product_category' => $category,
		'brand'                   => $vehicle['brand'],
		'model'                   => $vehicle['model'],
		'condition'               => $vehicle['condition'],
		'price'                   => $vehicle['price'].' '.$vehicle['currency'],
		'mileage'                 => $vehicle['mileage'].' KM',
		'color'                   => $vehicle['color'],
		'vin'                     => $vehicle['vin'],
		'year'                    => $vehicle['year'],
		'date_first_registered'   => $vehicle['first_registered'],
		'engine'                  => mobile_api_google_get_engine( $vehicle['fuel'] ),
		'co2_emissions'           => '' !== $vehicle['co2'] ? $vehicle['co2'].' g/km' : '',
		'certification'           => $certifications,
		'vehicle_fulfillment'     => array( 'option' => 'in_store', 'store_code' => $store_code ),
	);

	// Lets dealers correct single attributes, e.g. a model that mobile.de does not provide
	return apply_filters( 'mobile_api_google_feed_item', $item, $post_id, $vehicle );
}

// Scalars become one element, lists repeat the element, associative arrays become groups
function mobile_api_google_write_attribute( $xml, $name, $value ) {
	if ( is_array( $value ) && wp_is_numeric_array( $value ) ) {
		foreach ( $value as $entry )
			mobile_api_google_write_attribute( $xml, $name, $entry );
		return;
	}

	if ( null === $value || '' === $value )
		return;

	$xml->startElementNs( 'g', $name, null );
	if ( is_array( $value ) ) {
		foreach ( $value as $key => $entry )
			mobile_api_google_write_attribute( $xml, $key, $entry );
	} else {
		$xml->text( (string) $value );
	}
	$xml->endElement();
}

function mobile_api_google_feed_error( $status, $message ) {
	status_header( $status );
	header( 'Content-Type: text/plain; charset=utf-8', true );
	echo esc_html( $message );
	exit;
}

function mobile_api_google_feed_render() {
	header( 'X-Robots-Tag: noindex, nofollow', true );

	$store_code = get_option( 'mobile_api_google_store_code' );
	if ( empty( $store_code ) )
		mobile_api_google_feed_error( 503, __( 'Please enter a store code in the plugin settings first.', 'ad-integration-for-mobile-de-api' ) );

	$post_ids = get_posts( array(
		'post_type'      => 'mobile-api-vehicle',
		'post_status'    => 'publish',
		'posts_per_page' => -1,
		'fields'         => 'ids',
		'orderby'        => 'date',
		'order'          => 'DESC',
	) );
	update_meta_cache( 'post', $post_ids );

	$xml = new XMLWriter();
	$xml->openMemory();
	$xml->setIndent( true );
	$xml->startDocument( '1.0', 'UTF-8' );
	$xml->startElement( 'rss' );
	$xml->writeAttribute( 'version', '2.0' );
	$xml->writeAttribute( 'xmlns:g', 'http://base.google.com/ns/1.0' );
	$xml->startElement( 'channel' );
	$xml->writeElement( 'title', wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES ) );
	$xml->writeElement( 'link', home_url( '/' ) );
	$xml->writeElement( 'description', __( 'Vehicle inventory for Google vehicle ads', 'ad-integration-for-mobile-de-api' ) );

	foreach ( $post_ids as $post_id ) {
		$item = mobile_api_google_get_feed_item( $post_id, $store_code );
		if ( empty( $item ) )
			continue;

		$xml->startElement( 'item' );
		foreach ( $item as $name => $value )
			mobile_api_google_write_attribute( $xml, $name, $value );
		$xml->endElement();
	}

	$xml->endElement(); // channel
	$xml->endElement(); // rss
	$xml->endDocument();

	// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- XMLWriter escapes all content
	echo $xml->outputMemory();
	exit;
}

// Google compares the feed price with the structured data of the landing page
function mobile_api_google_structured_data() {
	if ( !is_singular( 'mobile-api-vehicle' ) || !mobile_api_google_is_active() )
		return;

	$vehicle = mobile_api_google_get_vehicle( get_queried_object_id() );
	if ( '' === $vehicle['price'] )
		return;

	$conditions = array(
		'new'  => 'https://schema.org/NewCondition',
		'used' => 'https://schema.org/UsedCondition',
	);

	$data = array_filter( array(
		'@context'                    => 'https://schema.org',
		'@type'                       => 'Car' === $vehicle['vehicle_class'] ? 'Car' : 'Vehicle',
		'name'                        => $vehicle['title'],
		'url'                         => $vehicle['link'],
		'image'                       => $vehicle['image'],
		'productID'                   => $vehicle['ad_id'],
		'brand'                       => array( '@type' => 'Brand', 'name' => $vehicle['brand'] ),
		'model'                       => $vehicle['model'],
		'vehicleIdentificationNumber' => $vehicle['vin'],
		'color'                       => $vehicle['color'],
		'itemCondition'               => $conditions[$vehicle['condition']] ?? '',
		'mileageFromOdometer'         => array( '@type' => 'QuantitativeValue', 'value' => $vehicle['mileage'], 'unitCode' => 'KMT' ),
		'offers'                      => array(
			'@type'         => 'Offer',
			'price'         => $vehicle['price'],
			'priceCurrency' => $vehicle['currency'],
			'availability'  => 'https://schema.org/InStock',
			'url'           => $vehicle['link'],
		),
	), function( $value ) {
		return '' !== $value;
	} );

	echo '<script type="application/ld+json">'.wp_json_encode( $data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_HEX_TAG ).'</script>'."\n";
}
add_action( 'wp_head', 'mobile_api_google_structured_data' );

// In the EEA Google requires the feed id to appear on the landing page
function mobile_api_google_ad_number( $content ) {
	if ( !is_singular( 'mobile-api-vehicle' ) || !in_the_loop() || !is_main_query() || !mobile_api_google_is_active() )
		return $content;

	$ad_id = maybe_unserialize( get_post_meta( get_the_ID(), 'mobile_api_mobileAdId', true ) );
	if ( empty( $ad_id ) )
		return $content;

	return $content.'<p class="mobile-api-ad-number">'.esc_html__( 'Ad number:', 'ad-integration-for-mobile-de-api' ).' '.esc_html( $ad_id ).'</p>';
}
add_filter( 'the_content', 'mobile_api_google_ad_number', 20 );