<?php
/**
 * A LINK THAT NAMES THE CHOICES: ?colour=white&size=m
 *
 * A shop's advert, email or Google Shopping item can point at one exact
 * version of a product, and the page arrives with that version already
 * chosen. Google asks for exactly this ("make sure the variant that matches
 * the product data is the one that appears on your landing page by default",
 * and "include product information in the HTTP response"), so the choice is
 * made by the SERVER, in the first response, never by a script after load:
 * the page draws itself already chosen through the same prefill machinery a
 * refused add and the cart's Edit link use.
 *
 * The words are readable on purpose. A question is named by what the shopper
 * reads above it ("Front personalisation" is front-personalisation), and the
 * two a clothing feed always carries have short names of their own: colour
 * (or color) and size. A value is the choice's own name ("Light Blue" is
 * light-blue, any case), or its key, and a size also answers to its long
 * name (medium for M) when nothing on the product is called that exactly.
 *
 * Nothing about it can hurt a page. A name or value the product does not
 * have is ignored without a word, a sold-out choice is never picked, and a
 * page with nothing to match renders exactly as it always has. It stands
 * aside for the cart's Edit link, for a posted form, and for anything that is
 * not a product page.
 *
 * Free in every build: the pick-one questions are free. The quantity grid's
 * half (the colour tile and a quantity in the size) and the Google pieces
 * live with the grid, in its Pro module.
 *
 * @package AddOnBoss
 */

defined( 'ABSPATH' ) || exit;

/**
 * The short names the two clothing questions answer to, by role.
 *
 * ONE place, filterable, so a shop whose theme or filter plugin already uses
 * ?colour= for something else can rename them (a prefix, another word)
 * without touching anything else: the matcher, the feed's links and the
 * documentation's examples all read this.
 *
 * @return array<string,string[]> role => the names it answers to; the first is the one links are written with.
 */
function addon_boss_preselect_param_names(): array {
	$names = array(
		'colour' => array( 'colour', 'color' ),
		'size'   => array( 'size' ),
	);
	/**
	 * The URL names of the colour and size questions.
	 *
	 * @param array<string,string[]> $names role => names; the first name is the one AddOnBoss writes in its own links.
	 */
	$names = (array) apply_filters( 'addon_boss_preselect_param_names', $names );
	$out   = array();
	foreach ( array( 'colour', 'size' ) as $role ) {
		$list = array();
		foreach ( (array) ( $names[ $role ] ?? array() ) as $n ) {
			$n = addon_boss_preselect_slug( (string) $n );
			// A name WordPress reads first could never reach the question.
			if ( '' !== $n && ! in_array( $n, $list, true ) && ! addon_boss_preselect_reserved( $n ) ) {
				$list[] = $n;
			}
		}
		$out[ $role ] = $list;
	}
	return $out;
}

/**
 * One spelling for names and values: lower case, accents off, every run of
 * anything that is not a letter or a digit becomes one hyphen. "Light Blue",
 * "light_blue" and "LIGHT-BLUE" all read light-blue.
 *
 * @param string $text Any name or value.
 * @return string
 */
function addon_boss_preselect_slug( string $text ): string {
	$text = remove_accents( wp_strip_all_tags( $text ) );
	$text = strtolower( $text );
	$text = (string) preg_replace( '/[^a-z0-9]+/', '-', $text );
	return trim( $text, '-' );
}

/**
 * The long and short names a garment size goes by. Each row is one size; a
 * value in a row reaches the choice whose own name is any other value in it,
 * and only when no choice on the product is called the value exactly.
 *
 * @return array<int,string[]>
 */
function addon_boss_preselect_size_aliases(): array {
	$rows = array(
		array( 'xxs', '2xs', 'xx-small', 'xxsmall', 'extra-extra-small' ),
		array( 'xs', 'x-small', 'xsmall', 'extra-small' ),
		array( 's', 'sm', 'small' ),
		array( 'm', 'md', 'med', 'medium' ),
		array( 'l', 'lg', 'large' ),
		array( 'xl', '1xl', 'x-large', 'xlarge', 'extra-large' ),
		array( 'xxl', '2xl', 'xx-large', 'xxlarge', '2x-large', 'extra-extra-large' ),
		array( 'xxxl', '3xl', 'xxx-large', '3x-large' ),
		array( 'xxxxl', '4xl', 'xxxx-large', '4x-large' ),
		array( 'xxxxxl', '5xl', 'xxxxx-large', '5x-large' ),
	);
	/**
	 * The size names that stand for each other in a link.
	 *
	 * @param array<int,string[]> $rows One row per size, every spelling slugged.
	 */
	return (array) apply_filters( 'addon_boss_preselect_size_aliases', $rows );
}

/**
 * Every spelling a link may use for one question's choices, mapped to the
 * choice's key: the name, then the key itself, then (only where no choice
 * already took it) the long or short name of a size and the other spelling of
 * grey. Built once, so the page, the structured data and the feed's links all
 * agree on what a value means.
 *
 * @param array $options The set's options (key, label).
 * @return array<string,string> spelling => option key.
 */
function addon_boss_preselect_value_map( array $options ): array {
	$map = array();
	foreach ( $options as $opt ) {
		$key  = (string) ( $opt['key'] ?? '' );
		$slug = addon_boss_preselect_slug( (string) ( $opt['label'] ?? '' ) );
		if ( '' !== $key && '' !== $slug && ! isset( $map[ $slug ] ) ) {
			$map[ $slug ] = $key;
		}
	}
	foreach ( $options as $opt ) {
		$key = (string) ( $opt['key'] ?? '' );
		$ks  = addon_boss_preselect_slug( $key );
		if ( '' !== $key && '' !== $ks && ! isset( $map[ $ks ] ) ) {
			$map[ $ks ] = $key;
		}
	}
	// The long and short names, never over an exact one.
	$rows = addon_boss_preselect_size_aliases();
	foreach ( $options as $opt ) {
		$key  = (string) ( $opt['key'] ?? '' );
		$slug = addon_boss_preselect_slug( (string) ( $opt['label'] ?? '' ) );
		if ( '' === $key || '' === $slug ) {
			continue;
		}
		$also = array();
		foreach ( $rows as $row ) {
			if ( in_array( $slug, (array) $row, true ) ) {
				$also = array_merge( $also, (array) $row );
			}
		}
		if ( false !== strpos( $slug, 'grey' ) ) {
			$also[] = str_replace( 'grey', 'gray', $slug );
		} elseif ( false !== strpos( $slug, 'gray' ) ) {
			$also[] = str_replace( 'gray', 'grey', $slug );
		}
		foreach ( $also as $alt ) {
			$alt = addon_boss_preselect_slug( (string) $alt );
			if ( '' !== $alt && ! isset( $map[ $alt ] ) ) {
				$map[ $alt ] = $key;
			}
		}
	}
	return $map;
}

/**
 * The value a link should carry for one choice: its name, unless another
 * choice in the same question shares that name, then its key.
 *
 * @param array  $options The set's options.
 * @param string $key     The chosen option's key.
 * @return string
 */
function addon_boss_preselect_value_for( array $options, string $key ): string {
	$map = addon_boss_preselect_value_map( $options );
	foreach ( $options as $opt ) {
		if ( (string) ( $opt['key'] ?? '' ) === $key ) {
			$slug = addon_boss_preselect_slug( (string) ( $opt['label'] ?? '' ) );
			if ( '' !== $slug && ( $map[ $slug ] ?? '' ) === $key ) {
				return $slug;
			}
		}
	}
	// Its key, but only where the key leads back to it: a key that reads as
	// another choice's name cannot be linked to at all.
	$by_key = addon_boss_preselect_slug( $key );
	return ( $map[ $by_key ] ?? '' ) === $key ? $by_key : '';
}

/**
 * Names a link can never use for a question: WordPress reads its own public
 * query words before any plugin does (?name= or ?page= on a product address
 * changes WHICH page loads), and WooCommerce and this plugin read theirs.
 *
 * @param string $slug A slugged name.
 * @return bool
 */
function addon_boss_preselect_reserved( string $slug ): bool {
	static $taken = null;
	if ( null === $taken ) {
		$taken = array( 'add-to-cart', 'quantity', 'variation-id', 'product-id', 'bb-edit', 'bb-edit-line', 'p', 'page', 's', 'name' );
		global $wp;
		if ( isset( $wp ) && is_object( $wp ) && ! empty( $wp->public_query_vars ) ) {
			foreach ( (array) $wp->public_query_vars as $qv ) {
				$taken[] = addon_boss_preselect_slug( (string) $qv );
			}
		}
		$taken = array_flip( array_filter( $taken ) );
	}
	return isset( $taken[ $slug ] ) || 0 === strpos( $slug, 'attribute-' ) || 0 === strpos( $slug, 'filter-' ) || 0 === strpos( $slug, 'utm-' );
}

/**
 * How strongly a set reads as a colour (0), a size (1) or anything else (2).
 * The quantity grid's own ranking, kept here so a build without the grid
 * still knows which question a colour link means.
 *
 * @param array $set A resolved set.
 * @return int
 */
function addon_boss_preselect_set_rank( array $set ): int {
	$name = strtolower( (string) ( $set['name'] ?? '' ) );
	if ( false !== strpos( $name, 'colour' ) || false !== strpos( $name, 'color' ) ) {
		return 0;
	}
	foreach ( (array) ( $set['options'] ?? array() ) as $o ) {
		if ( ! empty( $o['swatch'] ) ) {
			return 0;
		}
	}
	if ( false !== strpos( $name, 'size' ) || addon_boss_preselect_looks_like_size( $set ) ) {
		return 1;
	}
	return 2;
}

/**
 * Whether a set's choices read like garment sizes (XS to 7XL, numeric runs).
 *
 * @param array $set A resolved set.
 * @return bool
 */
function addon_boss_preselect_looks_like_size( array $set ): bool {
	$tokens = array( 'xs', 's', 'm', 'l', 'xl', 'xxl', 'xxxl', 'small', 'medium', 'large' );
	$opts   = (array) ( $set['options'] ?? array() );
	if ( count( $opts ) < 2 ) {
		return false;
	}
	$hits = 0;
	foreach ( $opts as $o ) {
		$lab = strtolower( trim( (string) ( $o['label'] ?? '' ) ) );
		if ( in_array( $lab, $tokens, true ) || preg_match( '/^\d+xl$/', $lab ) || preg_match( '/^(uk|eu|us)?\s*\d{1,2}(\.\d)?$/', $lab ) ) {
			++$hits;
		}
	}
	return $hits >= (int) ceil( count( $opts ) / 2 );
}

/**
 * Which of a product's questions is THE colour and which is THE size.
 *
 * Only the product's own pick-one choices that could be a colour or a size
 * axis: the first that reads as a colour (its name, or swatches on its
 * choices) and the first that reads as a size, in the order the shop
 * attached them, so a thread colour further down is never "the colour". On a
 * quantity grid the grid module answers instead, from the grid's own two
 * axes as the merchant arranged them.
 *
 * @param WC_Product $product The product.
 * @return array{colour:?array,size:?array} The resolved sets, or null.
 */
function addon_boss_preselect_roles( $product ): array {
	$roles = array(
		'colour' => null,
		'size'   => null,
	);
	if ( ! $product instanceof WC_Product || ! function_exists( 'addon_boss_virtual_axes' ) ) {
		return $roles;
	}
	$axes = array();
	foreach ( addon_boss_virtual_axes( $product ) as $axis ) {
		$set = (array) ( $axis['set'] ?? array() );
		if ( '' !== (string) ( $set['id'] ?? '' ) ) {
			$axes[] = $set;
		}
	}
	// The first that reads as a colour, the first that reads as a size, in the
	// order the shop attached them.
	foreach ( $axes as $set ) {
		$rank = addon_boss_preselect_set_rank( $set );
		if ( 0 === $rank && null === $roles['colour'] ) {
			$roles['colour'] = $set;
		} elseif ( 1 === $rank && null === $roles['size'] ) {
			$roles['size'] = $set;
		}
	}
	/**
	 * Which set is the colour and which the size, for links that name them.
	 *
	 * @param array{colour:?array,size:?array} $roles   The resolved sets.
	 * @param WC_Product                       $product The product.
	 */
	return (array) apply_filters( 'addon_boss_preselect_roles', $roles, $product );
}

/**
 * Every question a link can answer on this product's one-at-a-time page:
 * the colour and the size under their short names, then each pick-one
 * question under the name the shopper reads above it (and its library name).
 * The first question to claim a name keeps it.
 *
 * @param WC_Product $product The product.
 * @return array<string,array> slugged name => the set it answers.
 */
function addon_boss_preselect_targets( $product ): array {
	if ( ! $product instanceof WC_Product ) {
		return array();
	}
	$out   = array();
	$names = addon_boss_preselect_param_names();
	foreach ( addon_boss_preselect_roles( $product ) as $role => $set ) {
		if ( ! is_array( $set ) ) {
			continue;
		}
		foreach ( (array) ( $names[ $role ] ?? array() ) as $n ) {
			if ( ! isset( $out[ $n ] ) && ! addon_boss_preselect_reserved( $n ) ) {
				$out[ $n ] = $set;
			}
		}
	}
	foreach ( addon_boss_standalone_option_sets( $product ) as $set ) {
		if ( 'choices' !== (string) ( $set['kind'] ?? 'choices' ) || ! empty( $set['multi'] ) ) {
			continue; // a several-of question, or one priced off its own panel, has no single answer to name.
		}
		$own = array_unique(
			array_filter(
				array(
					addon_boss_preselect_slug( addon_boss_set_shopper_name( $set ) ),
					addon_boss_preselect_slug( (string) ( $set['name'] ?? '' ) ),
				)
			)
		);
		foreach ( $own as $n ) {
			if ( ! isset( $out[ $n ] ) && ! addon_boss_preselect_reserved( $n ) ) {
				$out[ $n ] = $set;
			}
		}
	}
	return $out;
}

/**
 * The link's own words, read once: slugged name => the raw value, for a plain
 * GET of a product page only. Nothing when the cart's Edit link is in play
 * (it fills the page from the line), when a form was posted (it keeps what
 * the shopper typed), or when the shop switched the feature off.
 *
 * @return array<string,string>
 */
function addon_boss_preselect_query(): array {
	$method = isset( $_SERVER['REQUEST_METHOD'] ) ? strtoupper( sanitize_text_field( wp_unslash( (string) $_SERVER['REQUEST_METHOD'] ) ) ) : 'GET';
	if ( 'GET' !== $method && 'HEAD' !== $method ) {
		return array();
	}
	// phpcs:disable WordPress.Security.NonceVerification.Recommended -- a read-only display choice; every value is matched against the product's own stored choices.
	foreach ( array( 'bb_edit', 'bb_edit_line', 'add-to-cart' ) as $bb_stop ) {
		if ( isset( $_GET[ $bb_stop ] ) || isset( $_POST[ $bb_stop ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Missing -- presence check only.
			return array();
		}
	}
	$out = array();
	foreach ( (array) $_GET as $bb_name => $bb_val ) {
		if ( ! is_string( $bb_name ) || is_array( $bb_val ) ) {
			continue;
		}
		$name = addon_boss_preselect_slug( $bb_name );
		$val  = addon_boss_preselect_slug( mb_substr( sanitize_text_field( wp_unslash( (string) $bb_val ) ), 0, 120 ) );
		if ( '' !== $name && '' !== $val && ! isset( $out[ $name ] ) ) {
			$out[ $name ] = $val;
		}
	}
	// phpcs:enable WordPress.Security.NonceVerification.Recommended
	return $out;
}

/**
 * The choices a link names on this product: set id => option key. Unknown
 * names and values, and sold-out choices, are simply not there.
 *
 * @param WC_Product $product  The product.
 * @param array|null $query    slugged name => slugged value; the current request when null.
 * @param bool       $sellable Only choices that can still be sold (the page never
 *                             chooses one that cannot); false to describe what the
 *                             link named, sold out or not (the page's markup does).
 * @return array<string,string>
 */
function addon_boss_preselect_picks( $product, ?array $query = null, bool $sellable = true ): array {
	if ( ! $product instanceof WC_Product ) {
		return array();
	}
	/**
	 * Whether a link may choose this product's options.
	 *
	 * @param bool       $on      True.
	 * @param WC_Product $product The product.
	 */
	if ( ! apply_filters( 'addon_boss_preselect_enabled', true, $product ) ) {
		return array();
	}
	$query = null === $query ? addon_boss_preselect_query() : $query;
	if ( ! $query ) {
		return array();
	}
	$role_ids = array();
	foreach ( addon_boss_preselect_roles( $product ) as $bb_rs ) {
		if ( is_array( $bb_rs ) ) {
			$role_ids[] = (string) ( $bb_rs['id'] ?? '' );
		}
	}
	$picks = array();
	foreach ( addon_boss_preselect_targets( $product ) as $name => $set ) {
		if ( ! isset( $query[ $name ] ) ) {
			continue;
		}
		$sid = (string) ( $set['id'] ?? '' );
		if ( '' === $sid || isset( $picks[ $sid ] ) ) {
			continue;
		}
		$map = addon_boss_preselect_value_map( (array) ( $set['options'] ?? array() ) );
		$key = $map[ addon_boss_preselect_slug( $query[ $name ] ) ] ?? '';
		if ( '' === $key ) {
			continue;
		}
		if ( ! in_array( $sid, $role_ids, true ) && empty( $set['required'] ) && ! addon_boss_preselect_free_choice( $set, $key ) ) {
			continue; // a paid extra is the shopper's to add, never a link's.
		}
		if ( $sellable && function_exists( 'addon_boss_option_stock_left' ) ) {
			$left = addon_boss_option_stock_left( $sid, $key );
			if ( null !== $left && $left <= 0 ) {
				continue; // never chosen for the shopper when it cannot be sold.
			}
		}
		$picks[ $sid ] = $key;
	}
	return $picks;
}

/**
 * Whether a choice adds nothing to the price. An OPTIONAL question answered
 * by a link may only be answered with one of these: a paid extra chosen on
 * the shopper's behalf is a pre-ticked box (consumer law across the UK and
 * the EU says an extra payment needs the shopper's own yes), so a link can
 * choose "No print" but never "Large back print". The colour, the size and
 * any REQUIRED question are the product itself, not an extra, and a link may
 * name any of their choices.
 *
 * @param array  $set A resolved set.
 * @param string $key The option's key.
 * @return bool
 */
function addon_boss_preselect_free_choice( array $set, string $key ): bool {
	foreach ( (array) ( $set['options'] ?? array() ) as $opt ) {
		if ( (string) ( $opt['key'] ?? '' ) === $key ) {
			$free = 0.0 === (float) ( $opt['delta'] ?? 0 ) && empty( $opt['fee'] ) && empty( $opt['price'] );
			/**
			 * Whether a link may choose this optional choice for the shopper.
			 *
			 * @param bool   $free True when the choice adds nothing to the price.
			 * @param array  $set  The question.
			 * @param string $key  The choice.
			 */
			return (bool) apply_filters( 'addon_boss_preselect_optional_choice', $free, $set, $key );
		}
	}
	return false;
}

/**
 * The colour and size a link names, resolved to their sets and options.
 *
 * @param WC_Product $product The product.
 * @param array|null $query   As addon_boss_preselect_picks().
 * @return array{colour:?array,size:?array} Each ['set' => array, 'option' => array] or null.
 */
function addon_boss_preselect_role_picks( $product, ?array $query = null, bool $sellable = true ): array {
	$out   = array(
		'colour' => null,
		'size'   => null,
	);
	$picks = addon_boss_preselect_picks( $product, $query, $sellable );
	if ( ! $picks ) {
		return $out;
	}
	foreach ( addon_boss_preselect_roles( $product ) as $role => $set ) {
		$sid = is_array( $set ) ? (string) ( $set['id'] ?? '' ) : '';
		if ( '' === $sid || ! isset( $picks[ $sid ] ) ) {
			continue;
		}
		foreach ( (array) ( $set['options'] ?? array() ) as $opt ) {
			if ( (string) ( $opt['key'] ?? '' ) === $picks[ $sid ] ) {
				$out[ $role ] = array(
					'set'    => $set,
					'option' => $opt,
				);
			}
		}
	}
	return $out;
}

/**
 * The link for one colour and size of a product, in the words this plugin
 * reads back: ?colour=white&size=m. Used for the feed's items, so a feed and
 * the page can never disagree about what a link means.
 *
 * @param WC_Product $product The product.
 * @param array      $colour  The colour set's option (or empty).
 * @param array      $size    The size set's option (or empty).
 * @return string
 */
function addon_boss_preselect_link( $product, array $colour = array(), array $size = array() ): string {
	if ( ! $product instanceof WC_Product ) {
		return '';
	}
	$roles = addon_boss_preselect_roles( $product );
	$names = addon_boss_preselect_param_names();
	$args  = array();
	foreach ( array(
		'colour' => $colour,
		'size'   => $size,
	) as $role => $opt ) {
		$set = $roles[ $role ] ?? null;
		if ( ! $opt || ! is_array( $set ) || empty( $names[ $role ][0] ) ) {
			continue;
		}
		$args[ $names[ $role ][0] ] = addon_boss_preselect_value_for( (array) ( $set['options'] ?? array() ), (string) ( $opt['key'] ?? '' ) );
	}
	return add_query_arg( $args, $product->get_permalink() );
}

add_action( 'template_redirect', 'addon_boss_preselect_seed', 11 );

/**
 * Arriving from a link that names choices: write them into the request where
 * the page's own prefill reads, so the one-at-a-time page draws itself with
 * those chips chosen, its total and its rules already settled, in the first
 * response. A question the request already answers is left alone, and a
 * quantity grid draws its own (its module reads the same picks).
 */
function addon_boss_preselect_seed(): void {
	if ( ! function_exists( 'is_product' ) || ! is_product() ) {
		return;
	}
	$product = wc_get_product( (int) get_queried_object_id() );
	if ( ! $product instanceof WC_Product ) {
		return;
	}
	if ( function_exists( 'addon_boss_product_uses_grid' ) && addon_boss_product_uses_grid( $product ) ) {
		return;
	}
	foreach ( addon_boss_preselect_picks( $product ) as $sid => $key ) {
		$field = addon_boss_standalone_field_name( (string) $sid );
		if ( ! isset( $_REQUEST[ $field ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- presence check only: a value the request already carries wins.
			$_REQUEST[ $field ] = wp_slash( (string) $key );
		}
	}
}