<?php
/**
 * Settings: defaults, reading, sanitizing and saving.
 *
 * @package BirchToad
 */

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

/**
 * Settings store.
 */
class BirchToad_Settings {

	/**
	 * Option name. Prefixed, because the WordPress.org scan rejects unprefixed options.
	 */
	const OPTION = 'birchtoad_settings';

	/**
	 * Merged settings, cached per request.
	 *
	 * @var array|null
	 */
	private static $cache = null;

	/**
	 * The default settings for a fresh install.
	 *
	 * Note on changing a default later: all() is merge( defaults(), saved ) and save() writes the
	 * whole merged array, so any site that has pressed Save once has every key of the schema as
	 * it then stood frozen in its option row. Changing a default therefore only moves sites that
	 * have never saved. Adding a NEW key moves everyone, because nobody has it stored.
	 *
	 * @return array
	 */
	public static function defaults() {
		$features = array();

		foreach ( BirchToad_Features::all() as $key => $feature ) {
			$features[ $key ] = ! empty( $feature['on'] );
		}

		$defaults = array(
			'widget'    => array(
				'enabled'            => true,
				'position'           => 'bottom-right',
				'offset_x'           => 20,
				'offset_y'           => 20,
				'size'               => 'medium',
				'shape'              => 'circle',
				'icon'               => 'birchtoad',
				'accent'             => '#2F57F0',
				'header_title'       => '',
				'trigger_label'      => '',
				'open_on_load'       => false,
				'hide_on_mobile'     => false,
				'hide_for_logged_in' => false,
				'shortcut'           => true,
				// Off by default, in every edition, and switchable on the free build.
				// WordPress.org guideline 10 requires a credit display to default to not showing.
				'credit'             => false,
			),
			'features'  => $features,
			'statement' => array(
				'page_id' => 0,
			),
			'languages' => array(
				'mode'    => 'site',
				'default' => '',
			),
			'advanced'  => array(
				'exclude_ids'    => '',
				'post_types'     => array(),
				'uninstall_wipe' => false,
			),
		);

		/**
		 * Filters the settings schema defaults.
		 *
		 * The paid build adds its own keys here rather than the core making room for them.
		 *
		 * @param array $defaults Defaults.
		 */
		return apply_filters( 'birchtoad_settings_schema', $defaults );
	}

	/**
	 * Every setting, defaults merged under whatever the site saved.
	 *
	 * @return array
	 */
	public static function all() {
		if ( null !== self::$cache ) {
			return self::$cache;
		}

		$saved = get_option( self::OPTION, array() );

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

		$merged = self::defaults();

		foreach ( $merged as $group => $fields ) {
			if ( isset( $saved[ $group ] ) && is_array( $saved[ $group ] ) ) {
				$merged[ $group ] = array_merge( $fields, $saved[ $group ] );
			}
		}

		self::$cache = $merged;

		return self::$cache;
	}

	/**
	 * One setting.
	 *
	 * @param string $group   Group key.
	 * @param string $key     Field key.
	 * @param mixed  $fallback Returned when the field does not exist.
	 * @return mixed
	 */
	public static function get( $group, $key, $fallback = null ) {
		$all = self::all();

		if ( isset( $all[ $group ][ $key ] ) ) {
			return $all[ $group ][ $key ];
		}

		return $fallback;
	}

	/**
	 * Whether a feature exists in this edition and is switched on for the site.
	 *
	 * There is no license check here. A feature the edition cannot run is absent from the
	 * registry, so an unknown key is simply not a feature.
	 *
	 * @param string $key Feature key.
	 * @return bool
	 */
	public static function feature_on( $key ) {
		if ( null === BirchToad_Features::get( $key ) ) {
			return false;
		}

		return (bool) self::get( 'features', $key, false );
	}

	/**
	 * Saves a submitted settings group, sanitized.
	 *
	 * Starts from the merged array so a partial submission cannot drop keys the form did not
	 * render.
	 *
	 * @param string $group Group key.
	 * @param array  $input Raw submitted values for that group.
	 * @return bool Whether the option changed.
	 */
	public static function save_group( $group, array $input ) {
		$all = self::all();

		if ( ! isset( $all[ $group ] ) ) {
			return false;
		}

		$all[ $group ] = self::sanitize_group( $group, $input, $all[ $group ] );

		self::$cache = $all;

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

	/**
	 * Sanitizes one group against its current values.
	 *
	 * @param string $group   Group key.
	 * @param array  $input   Raw values.
	 * @param array  $current Current values, used as the type template and the fallback.
	 * @return array
	 */
	private static function sanitize_group( $group, array $input, array $current ) {
		switch ( $group ) {
			case 'widget':
				return self::sanitize_widget( $input, $current );

			case 'features':
				$out = array();
				foreach ( BirchToad_Features::all() as $key => $feature ) {
					$out[ $key ] = ! empty( $input[ $key ] );
				}
				return $out;

			case 'statement':
				$current['page_id'] = isset( $input['page_id'] ) ? absint( $input['page_id'] ) : 0;
				return $current;

			case 'languages':
				$modes              = array( 'site', 'visitor', 'fixed' );
				$mode               = isset( $input['mode'] ) ? sanitize_key( $input['mode'] ) : 'site';
				$current['mode']    = in_array( $mode, $modes, true ) ? $mode : 'site';
				$current['default'] = isset( $input['default'] ) ? sanitize_text_field( wp_unslash( $input['default'] ) ) : '';
				return $current;

			case 'advanced':
				$current['exclude_ids']    = isset( $input['exclude_ids'] )
					? self::sanitize_id_list( wp_unslash( $input['exclude_ids'] ) )
					: '';
				$current['post_types']     = isset( $input['post_types'] ) && is_array( $input['post_types'] )
					? array_values( array_map( 'sanitize_key', $input['post_types'] ) )
					: array();
				$current['uninstall_wipe'] = ! empty( $input['uninstall_wipe'] );
				return $current;
		}

		/**
		 * Filters the sanitized values of a settings group the core does not know.
		 *
		 * @param array  $current Current values.
		 * @param array  $input   Raw values.
		 * @param string $group   Group key.
		 */
		return apply_filters( 'birchtoad_sanitize_group', $current, $input, $group );
	}

	/**
	 * Sanitizes the widget group.
	 *
	 * @param array $input   Raw values.
	 * @param array $current Current values.
	 * @return array
	 */
	private static function sanitize_widget( array $input, array $current ) {
		$positions = array( 'bottom-right', 'bottom-left', 'middle-right', 'middle-left', 'top-right', 'top-left' );
		$sizes     = array( 'small', 'medium', 'large' );
		$shapes    = array( 'circle', 'rounded', 'square' );
		$icons     = array( 'birchtoad', 'contrast', 'text', 'sliders', 'eye', 'wheelchair', 'none' );

		$current['enabled']            = ! empty( $input['enabled'] );
		$current['open_on_load']       = ! empty( $input['open_on_load'] );
		$current['hide_on_mobile']     = ! empty( $input['hide_on_mobile'] );
		$current['hide_for_logged_in'] = ! empty( $input['hide_for_logged_in'] );
		$current['shortcut']           = ! empty( $input['shortcut'] );
		$current['credit']             = ! empty( $input['credit'] );

		$current['position'] = self::one_of( $input, 'position', $positions, $current['position'] );
		$current['size']     = self::one_of( $input, 'size', $sizes, $current['size'] );
		$current['shape']    = self::one_of( $input, 'shape', $shapes, $current['shape'] );
		$current['icon']     = self::one_of( $input, 'icon', $icons, $current['icon'] );

		$current['offset_x'] = isset( $input['offset_x'] ) ? min( 200, max( 0, absint( $input['offset_x'] ) ) ) : $current['offset_x'];
		$current['offset_y'] = isset( $input['offset_y'] ) ? min( 200, max( 0, absint( $input['offset_y'] ) ) ) : $current['offset_y'];

		if ( isset( $input['accent'] ) ) {
			$accent            = sanitize_hex_color( wp_unslash( $input['accent'] ) );
			$current['accent'] = $accent ? $accent : $current['accent'];
		}

		$current['header_title']  = isset( $input['header_title'] )
			? sanitize_text_field( wp_unslash( $input['header_title'] ) )
			: $current['header_title'];
		$current['trigger_label'] = isset( $input['trigger_label'] )
			? sanitize_text_field( wp_unslash( $input['trigger_label'] ) )
			: $current['trigger_label'];

		return $current;
	}

	/**
	 * Returns a submitted value only when it is one of the allowed ones.
	 *
	 * @param array  $input    Raw values.
	 * @param string $key      Field key.
	 * @param array  $allowed  Allowed values.
	 * @param mixed  $fallback Returned otherwise.
	 * @return mixed
	 */
	private static function one_of( array $input, $key, array $allowed, $fallback ) {
		if ( ! isset( $input[ $key ] ) ) {
			return $fallback;
		}

		$value = sanitize_key( $input[ $key ] );

		return in_array( $value, $allowed, true ) ? $value : $fallback;
	}

	/**
	 * Normalizes a comma separated list of post IDs.
	 *
	 * @param string $raw Raw input.
	 * @return string
	 */
	private static function sanitize_id_list( $raw ) {
		$ids = array_filter( array_map( 'absint', preg_split( '/[\s,]+/', (string) $raw ) ) );

		return implode( ',', array_unique( $ids ) );
	}

	/**
	 * Clears the per-request cache.
	 *
	 * @return void
	 */
	public static function flush() {
		self::$cache = null;
	}
}