<?php
/**
 * Global button shadow.
 *
 * One site-wide setting (VEFmultiBooking > Style) that adds a box-shadow
 * to every VEFmultiBooking button, and to VEFmultiBooking Pro's buttons
 * through the "vefmb_button_shadow_selectors" filter.
 *
 * Kept in its own class, with neutral input/output (plain values in, CSS
 * out), so it can be reused by other plugins.
 *
 * @package VEFmultiBooking
 * @since   0.20.3
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Builds the button shadow value and the CSS rule that applies it.
 */
class VEFMB_Button_Shadow {

	/**
	 * Default offsets/blur/spread (px), used when a field is left empty.
	 * A soft shadow slightly below the button.
	 */
	const DEFAULTS = array(
		'x'      => 0,
		'y'      => 2,
		'blur'   => 6,
		'spread' => 0,
	);

	/**
	 * Allowed range for each value (px).
	 */
	const LIMITS = array(
		'x'      => array( -50, 50 ),
		'y'      => array( -50, 50 ),
		'blur'   => array( 0, 100 ),
		'spread' => array( -50, 50 ),
	);

	/**
	 * Free buttons that receive the shadow. Filled buttons and outlined
	 * buttons only — icon-only controls (volume, lyrics, quantity...)
	 * are left out, a shadow around a transparent box looks broken.
	 */
	const SELECTORS = array(
		'.vefmb-widget__button',
	);

	/**
	 * Sanitizes one numeric field for saving: empty stays empty (default
	 * applied at output time), anything else is an integer within range.
	 *
	 * @param string $key Field key: x, y, blur or spread.
	 * @param mixed  $raw Submitted value (already unslashed).
	 * @return int|string Integer within range, or '' when left empty.
	 */
	public static function sanitize_number( $key, $raw ) {
		$raw = trim( (string) $raw );
		if ( '' === $raw || ! isset( self::LIMITS[ $key ] ) ) {
			return '';
		}
		list( $min, $max ) = self::LIMITS[ $key ];
		return max( $min, min( $max, (int) $raw ) );
	}

	/**
	 * Builds the box-shadow value from raw settings.
	 *
	 * @param array $settings Keys: color, x, y, blur, spread.
	 * @return string CSS value (e.g. "0px 2px 6px 0px #00000040"), or ''
	 *                when no color is set (no shadow at all).
	 */
	public static function build_value( array $settings ) {
		$color = isset( $settings['color'] ) ? preg_replace( '/[^#a-zA-Z0-9(),.%\s-]/', '', (string) $settings['color'] ) : '';
		$color = trim( $color );
		if ( '' === $color ) {
			return '';
		}
		$parts = array();
		foreach ( array_keys( self::DEFAULTS ) as $key ) {
			$value   = isset( $settings[ $key ] ) ? self::sanitize_number( $key, $settings[ $key ] ) : '';
			$parts[] = ( '' === $value ? self::DEFAULTS[ $key ] : $value ) . 'px';
		}
		return implode( ' ', $parts ) . ' ' . $color;
	}

	/**
	 * Returns the full list of selectors, Free ones plus those added by
	 * other plugins through the filter.
	 *
	 * @return string[] Cleaned selectors.
	 */
	public static function get_selectors() {
		/**
		 * Filters the buttons that receive the global button shadow
		 * (VEFmultiBooking Pro adds its own).
		 *
		 * @since 0.20.3
		 *
		 * @param string[] $selectors CSS selectors, one button type each.
		 */
		$selectors = apply_filters( 'vefmb_button_shadow_selectors', self::SELECTORS );
		$clean     = array();
		foreach ( (array) $selectors as $selector ) {
			// A selector never needs braces, semicolons, at-rules or
			// markup: stripping them keeps a filtered value from breaking
			// out of the rule.
			$selector = trim( preg_replace( '/[{};@<\\\\]/', '', wp_strip_all_tags( (string) $selector ) ) );
			if ( '' !== $selector ) {
				$clean[] = $selector;
			}
		}
		return array_values( array_unique( $clean ) );
	}

	/**
	 * Builds the CSS applying the shadow, or '' when no shadow is set.
	 *
	 * The rule is only printed when a shadow is set: a declaration with an
	 * empty variable would remove a shadow the theme gives its buttons.
	 *
	 * @param array $settings Keys: color, x, y, blur, spread.
	 * @return string CSS rules.
	 */
	public static function build_css( array $settings ) {
		$value = self::build_value( $settings );
		if ( '' === $value ) {
			return '';
		}
		$selectors = self::get_selectors();
		if ( ! $selectors ) {
			return '';
		}
		$css = ':root{--vefmb-button-shadow:' . $value . '}';
		// One rule per selector: in a grouped list, a single invalid
		// selector (e.g. one added through the filter) would make the
		// browser drop the whole rule for every button.
		foreach ( $selectors as $selector ) {
			$css .= $selector . '{box-shadow:var(--vefmb-button-shadow)}';
		}
		return $css;
	}

	/**
	 * Reads the saved settings.
	 *
	 * @return array Keys: color, x, y, blur, spread.
	 */
	public static function get_settings() {
		return array(
			'color'  => VEFMB_Settings::get( 'style_button_shadow_color', '' ),
			'x'      => VEFMB_Settings::get( 'style_button_shadow_x', '' ),
			'y'      => VEFMB_Settings::get( 'style_button_shadow_y', '' ),
			'blur'   => VEFMB_Settings::get( 'style_button_shadow_blur', '' ),
			'spread' => VEFMB_Settings::get( 'style_button_shadow_spread', '' ),
		);
	}
}