<?php
/**
 * Settings: defaults, reading and cleaning.
 *
 * @package StickyAddToCartBar
 */

namespace StickyAddToCartBar;

defined( 'ABSPATH' ) || exit;

/**
 * Plugin settings, stored in one option.
 */
class Settings {

	/**
	 * Option name.
	 */
	const OPTION = 'satcbar_options';

	/**
	 * Cached settings for this request.
	 *
	 * @var array|null
	 */
	private static $cache = null;

	/**
	 * Default values.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			'enabled'      => true,
			'desktop'      => true,
			'mobile'       => true,
			'position'     => 'bottom',
			'trigger'      => 'scroll',
			'show_image'   => true,
			'show_price'   => true,
			'show_qty'     => true,
			'button_text'  => '',
			'style'        => 'light',
			'button_color' => '',
			'delete_data'  => false,
		);
	}

	/**
	 * Allowed values for the choice settings.
	 *
	 * @return array<string, string[]>
	 */
	public static function choices() {
		return array(
			'position' => array( 'bottom', 'top' ),
			'trigger'  => array( 'scroll', 'always' ),
			'style'    => array( 'light', 'dark' ),
		);
	}

	/**
	 * Current settings merged over the defaults.
	 *
	 * @return array
	 */
	public static function get() {
		if ( null === self::$cache ) {
			$saved       = get_option( self::OPTION, array() );
			self::$cache = self::sanitize( is_array( $saved ) ? $saved : array() );
		}
		return self::$cache;
	}

	/**
	 * Cleans raw input (from the form or the database) into a full settings array.
	 *
	 * @param array $input Raw values.
	 * @return array
	 */
	public static function sanitize( array $input ) {
		$defaults = self::defaults();
		$clean    = array();
		foreach ( $defaults as $key => $default ) {
			$value = array_key_exists( $key, $input ) ? $input[ $key ] : $default;
			if ( is_bool( $default ) ) {
				$clean[ $key ] = (bool) $value && '0' !== $value;
			} elseif ( isset( self::choices()[ $key ] ) ) {
				$value         = sanitize_key( (string) $value );
				$clean[ $key ] = in_array( $value, self::choices()[ $key ], true ) ? $value : $default;
			} elseif ( 'button_color' === $key ) {
				$color         = sanitize_hex_color( (string) $value );
				$clean[ $key ] = $color ? $color : '';
			} else {
				$clean[ $key ] = sanitize_text_field( (string) $value );
			}
		}
		return $clean;
	}

	/**
	 * Saves settings from the form.
	 *
	 * @param array $input Raw form values.
	 */
	public static function save( array $input ) {
		$clean = self::sanitize( $input );
		update_option( self::OPTION, $clean );
		self::$cache = $clean;
	}

	/**
	 * Black or white text, whichever reads better on a background color.
	 *
	 * @param string $hex Background color (#rrggbb or #rgb).
	 * @return string
	 */
	public static function text_color_for( $hex ) {
		$hex = ltrim( (string) $hex, '#' );
		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}
		if ( 6 !== strlen( $hex ) ) {
			return '#ffffff';
		}
		$channel = static function ( $part ) {
			$c = hexdec( $part ) / 255;
			return $c <= 0.03928 ? $c / 12.92 : pow( ( $c + 0.055 ) / 1.055, 2.4 );
		};
		$lum     = 0.2126 * $channel( substr( $hex, 0, 2 ) ) + 0.7152 * $channel( substr( $hex, 2, 2 ) ) + 0.0722 * $channel( substr( $hex, 4, 2 ) );
		// Contrast with white is (1.05) / (lum + 0.05); with black (lum + 0.05) / 0.05. Pick the higher one.
		return ( 1.05 / ( $lum + 0.05 ) ) >= ( ( $lum + 0.05 ) / 0.05 ) ? '#ffffff' : '#111111';
	}
}