<?php
/**
 * Ajustes del plugin: valores por defecto, lectura y saneado.
 *
 * @package Feel_Accessibility
 */

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

class Feel_Accessibility_Settings {

	const OPTION = 'feel_accessibility_settings';

	/** Verde oscuro de la marca Feel (contraste 7,9:1 con blanco). */
	const BRAND_COLOR = '#065c4e';

	/**
	 * Funciones disponibles en la barra.
	 * Clave = id de la función; valor = clave de estado que usa el front-end (null = sin estado guardado).
	 *
	 * @return array
	 */
	public static function features() {
		return array(
			'text_size' => 'text',
			'spacing'   => 'spacing',
			'font'      => 'font',
			'align'     => 'align',
			'contrast'  => 'contrast',
			'links'     => 'links',
			'headings'  => 'headings',
			'guide'     => 'guide',
			'images'    => 'images',
			'tts'       => null,
			'motion'    => 'motion',
			'cursor'    => 'cursor',
			'focus'     => 'focus',
		);
	}

	/**
	 * Posiciones permitidas del botón.
	 *
	 * @return string[]
	 */
	public static function positions() {
		return array( 'bottom-right', 'bottom-left', 'top-right', 'top-left' );
	}

	/**
	 * Tamaños del botón en píxeles.
	 *
	 * @return int[]
	 */
	public static function sizes() {
		return array(
			'small'  => 44,
			'medium' => 52,
			'large'  => 64,
		);
	}

	/**
	 * Valores por defecto.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			'enabled'        => 1,
			'admins_only'    => 0,
			'show_trigger'   => 1,
			'position'       => 'bottom-right',
			'offset_x'       => 20,
			'offset_y'       => 20,
			'size'           => 'medium',
			'color'          => self::BRAND_COLOR,
			'features'       => array_fill_keys( array_keys( self::features() ), 1 ),
			'remember'       => 1,
			'respect_motion' => 1,
			'statement_url'  => '',
			'contact_cta'    => 0,
			'show_credit'    => 0,
			'contact_url'    => '',
			'contact_text'   => '',
		);
	}

	/**
	 * Ajustes guardados combinados con los valores por defecto.
	 *
	 * @return array
	 */
	public static function get() {
		$saved    = get_option( self::OPTION, array() );
		$saved    = is_array( $saved ) ? $saved : array();
		$defaults = self::defaults();
		$settings = array_merge( $defaults, $saved );

		$features = ( isset( $saved['features'] ) && is_array( $saved['features'] ) ) ? $saved['features'] : array();

		$settings['features'] = array_merge( $defaults['features'], $features );

		return $settings;
	}

	/**
	 * Sanea el array enviado desde el formulario (o desde update_option).
	 *
	 * @param mixed $input Datos sin sanear.
	 * @return array
	 */
	public static function sanitize( $input ) {
		$defaults = self::defaults();
		$input    = is_array( $input ) ? $input : array();
		$out      = array();

		foreach ( array( 'enabled', 'admins_only', 'show_trigger', 'remember', 'respect_motion', 'contact_cta', 'show_credit' ) as $key ) {
			$out[ $key ] = empty( $input[ $key ] ) ? 0 : 1;
		}

		$position        = isset( $input['position'] ) ? (string) $input['position'] : '';
		$out['position'] = in_array( $position, self::positions(), true ) ? $position : $defaults['position'];

		$size        = isset( $input['size'] ) ? (string) $input['size'] : '';
		$out['size'] = array_key_exists( $size, self::sizes() ) ? $size : $defaults['size'];

		foreach ( array( 'offset_x', 'offset_y' ) as $key ) {
			$value       = isset( $input[ $key ] ) ? (int) $input[ $key ] : $defaults[ $key ];
			$out[ $key ] = max( 0, min( 200, $value ) );
		}

		$color        = isset( $input['color'] ) ? sanitize_hex_color( (string) $input['color'] ) : '';
		$out['color'] = $color ? strtolower( $color ) : $defaults['color'];

		$out['features'] = array();
		foreach ( array_keys( self::features() ) as $id ) {
			$out['features'][ $id ] = empty( $input['features'][ $id ] ) ? 0 : 1;
		}

		foreach ( array( 'statement_url', 'contact_url' ) as $key ) {
			$url         = isset( $input[ $key ] ) ? trim( (string) $input[ $key ] ) : '';
			$out[ $key ] = '' === $url ? '' : esc_url_raw( $url, array( 'http', 'https', 'mailto' ) );
		}

		$text                = isset( $input['contact_text'] ) ? sanitize_text_field( (string) $input['contact_text'] ) : '';
		$out['contact_text'] = function_exists( 'mb_substr' ) ? mb_substr( $text, 0, 60 ) : substr( $text, 0, 60 );

		return $out;
	}

	/**
	 * Color de icono (blanco o negro) con mejor contraste sobre el color de fondo.
	 *
	 * @param string $background Color hexadecimal.
	 * @return string
	 */
	public static function icon_color( $background ) {
		return self::contrast_ratio( '#ffffff', $background ) >= self::contrast_ratio( '#000000', $background ) ? '#ffffff' : '#000000';
	}

	/**
	 * Ratio de contraste WCAG entre dos colores hexadecimales.
	 *
	 * @param string $a Color A.
	 * @param string $b Color B.
	 * @return float
	 */
	public static function contrast_ratio( $a, $b ) {
		$la = self::luminance( $a );
		$lb = self::luminance( $b );

		return ( max( $la, $lb ) + 0.05 ) / ( min( $la, $lb ) + 0.05 );
	}

	/**
	 * Luminancia relativa de un color hexadecimal.
	 *
	 * @param string $hex Color (#rgb o #rrggbb).
	 * @return float
	 */
	private static function luminance( $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 ) || ! ctype_xdigit( $hex ) ) {
			return 0.0;
		}

		$channels = array();
		foreach ( array( 0, 2, 4 ) as $offset ) {
			$c          = hexdec( substr( $hex, $offset, 2 ) ) / 255;
			$channels[] = ( $c <= 0.03928 ) ? $c / 12.92 : pow( ( $c + 0.055 ) / 1.055, 2.4 );
		}

		return 0.2126 * $channels[0] + 0.7152 * $channels[1] + 0.0722 * $channels[2];
	}

	/**
	 * Crea los ajustes por defecto al activar el plugin (sin pisar los existentes).
	 *
	 * @return void
	 */
	public static function activate() {
		add_option( self::OPTION, self::defaults() );
	}
}