<?php
/**
 * Options handling.
 *
 * Every repair is off by default. A plugin that silently rewrites a live site's
 * markup the moment it is activated is a plugin that gets one-star reviews from
 * people whose layout broke, so each fix is an explicit, reversible choice.
 *
 * @package AccessVane
 */

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

/**
 * Reads and writes the plugin's settings.
 */
class AccessVane_Settings {

	const OPTION = 'accessvane_settings';

	/**
	 * Default settings.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			// Repairs, all opt-in.
			'fix_skip_link'        => false,
			'fix_focus_visible'    => false,
			'fix_viewport_zoom'    => false,
			'fix_link_underline'   => false,
			'fix_iframe_titles'    => false,
			'fix_scrollable_focus' => false,
			'fix_landmark_labels'  => false,
			'fix_image_alt'        => false,
			'fix_form_labels'      => false,
			'fix_lang_attribute'   => false,

			// Repair configuration.
			'skip_link_target'     => '#content',
			'skip_link_text'       => '',
			'focus_ring_color'     => '#0b63ce',
			'focus_ring_width'     => 3,

			// Statement page.
			'statement_page_id'    => 0,

			// Housekeeping.
			'delete_data_on_uninstall' => false,
		);
	}

	/**
	 * All settings, merged over the defaults.
	 *
	 * @return array
	 */
	public static function all() {
		$stored = get_option( self::OPTION, array() );

		if ( ! is_array( $stored ) ) {
			$stored = array();
		}

		return wp_parse_args( $stored, self::defaults() );
	}

	/**
	 * One setting.
	 *
	 * @param string $key     Setting name.
	 * @param mixed  $default Fallback when the key is unknown.
	 * @return mixed
	 */
	public static function get( $key, $default = null ) {
		$all = self::all();

		if ( array_key_exists( $key, $all ) ) {
			return $all[ $key ];
		}

		return $default;
	}

	/**
	 * Whether a repair is switched on.
	 *
	 * @param string $key Setting name.
	 * @return bool
	 */
	public static function enabled( $key ) {
		return (bool) self::get( $key, false );
	}

	/**
	 * Persist a full settings array, sanitising every value.
	 *
	 * @param array $input Raw input.
	 * @return array The saved settings.
	 */
	public static function save( array $input ) {
		$defaults = self::defaults();
		$clean    = array();

		foreach ( $defaults as $key => $default ) {
			if ( is_bool( $default ) ) {
				$clean[ $key ] = ! empty( $input[ $key ] );
				continue;
			}

			if ( ! isset( $input[ $key ] ) ) {
				$clean[ $key ] = $default;
				continue;
			}

			switch ( $key ) {
				case 'skip_link_target':
					$clean[ $key ] = self::sanitize_fragment( $input[ $key ], $default );
					break;

				case 'focus_ring_color':
					$color         = sanitize_hex_color( $input[ $key ] );
					$clean[ $key ] = $color ? $color : $default;
					break;

				case 'focus_ring_width':
					$clean[ $key ] = max( 1, min( 6, absint( $input[ $key ] ) ) );
					break;

				case 'statement_page_id':
					$clean[ $key ] = absint( $input[ $key ] );
					break;

				default:
					$clean[ $key ] = sanitize_text_field( $input[ $key ] );
					break;
			}
		}

		update_option( self::OPTION, $clean );

		return $clean;
	}

	/**
	 * Update a single setting without disturbing the rest.
	 *
	 * @param string $key   Setting name.
	 * @param mixed  $value New value.
	 * @return void
	 */
	public static function set( $key, $value ) {
		$all         = self::all();
		$all[ $key ] = $value;

		update_option( self::OPTION, $all );
	}

	/**
	 * Write defaults on activation without clobbering an existing configuration.
	 *
	 * @return void
	 */
	public static function seed_defaults() {
		if ( false === get_option( self::OPTION, false ) ) {
			add_option( self::OPTION, self::defaults() );
		}
	}

	/**
	 * Keep the skip-link target to a safe CSS id fragment.
	 *
	 * The value is printed into an href, so anything that is not a plain
	 * "#identifier" is rejected rather than escaped — there is no legitimate
	 * reason for it to contain anything else.
	 *
	 * @param string $value    Raw value.
	 * @param string $fallback Value to use when the input is unusable.
	 * @return string
	 */
	public static function sanitize_fragment( $value, $fallback = '#content' ) {
		$value = ltrim( trim( (string) $value ), '#' );
		$value = preg_replace( '/[^A-Za-z0-9_\-]/', '', $value );

		if ( '' === $value ) {
			return $fallback;
		}

		return '#' . $value;
	}
}