<?php
/**
 * Dashboard display settings: defaults, validation and the public whitelist.
 *
 * @package PulseCast
 */

namespace PulseCast\Support;

use PulseCast\Feeds\Feed_Normalizer;

/**
 * Single source of truth for dashboard settings.
 *
 * Each field declares its type, default and whether it may appear in public output. The same
 * declaration validates input and defines the public whitelist, so a private setting cannot
 * reach an anonymous visitor by accident.
 */
final class Settings_Schema {

	public const MIN_REFRESH_MINUTES = 5;

	/**
	 * Field declarations.
	 *
	 * @var array<string, array<string, mixed>>
	 */
	private const FIELDS = array(
		'layout'                 => array(
			'type'    => 'enum',
			'values'  => array( 'command', 'cards', 'list' ),
			'default' => 'command',
			'public'  => true,
		),
		'theme'                  => array(
			'type'    => 'enum',
			'values'  => array( 'light', 'dark' ),
			'default' => 'dark',
			'public'  => true,
		),
		'palette'                => array(
			'type'    => 'enum',
			'values'  => array( 'midnight', 'ocean', 'ember', 'forest', 'light' ),
			'default' => 'midnight',
			'public'  => true,
		),
		'refresh_interval'       => array(
			'type'    => 'int',
			'min'     => self::MIN_REFRESH_MINUTES,
			'max'     => 1440,
			'default' => 15,
			'public'  => false,
		),
		'max_items'              => array(
			'type'    => 'int',
			'min'     => 5,
			'max'     => 100,
			'default' => 30,
			'public'  => true,
		),
		'show_source'            => array(
			'type'    => 'bool',
			'default' => true,
			'public'  => true,
		),
		'show_time'              => array(
			'type'    => 'bool',
			'default' => true,
			'public'  => true,
		),
		'show_images'            => array(
			'type'    => 'bool',
			'default' => true,
			'public'  => true,
		),
		'headlines_heading'      => array(
			'type'    => 'text',
			'max'     => 40,
			'default' => 'Latest Headlines',
			'public'  => true,
		),
		'show_headlines_heading' => array(
			'type'    => 'bool',
			'default' => true,
			'public'  => true,
		),
	);

	/**
	 * Default value for every setting.
	 *
	 * @return array<string, mixed>
	 */
	public static function defaults(): array {
		return array_map( static fn( array $field ) => $field['default'], self::FIELDS );
	}

	/**
	 * Validates input into a complete settings array.
	 *
	 * Unknown keys are dropped. Missing, wrongly typed and invalid values fall back to the
	 * default. Integers are clamped to their allowed range.
	 *
	 * @param array<string, mixed> $input Raw settings.
	 * @return array<string, mixed>
	 */
	public static function sanitize( array $input ): array {
		$clean = array();

		foreach ( self::FIELDS as $name => $field ) {
			$clean[ $name ] = self::sanitize_value( $field, $input[ $name ] ?? null );
		}

		// Dashboards saved before palettes existed only have a theme. Derive the palette from it, and
		// keep `theme` (dark or light) consistent with the palette for anything that still reads it.
		if ( ! in_array( $input['palette'] ?? null, self::FIELDS['palette']['values'], true ) ) {
			$clean['palette'] = 'light' === $clean['theme'] ? 'light' : 'midnight';
		}

		$clean['theme'] = 'light' === $clean['palette'] ? 'light' : 'dark';

		return $clean;
	}

	/**
	 * The settings that may be shown to anonymous visitors.
	 *
	 * @param array<string, mixed> $settings Settings, validated first.
	 * @return array<string, mixed>
	 */
	public static function public_settings( array $settings ): array {
		$settings = self::sanitize( $settings );
		$public   = array();

		foreach ( self::FIELDS as $name => $field ) {
			if ( $field['public'] ) {
				$public[ $name ] = $settings[ $name ];
			}
		}

		return $public;
	}

	/**
	 * Validates one value against its field declaration.
	 *
	 * @param array<string, mixed> $field Field declaration.
	 * @param mixed                $value Raw value.
	 * @return mixed
	 */
	private static function sanitize_value( array $field, $value ) {
		switch ( $field['type'] ) {
			case 'enum':
				return ( is_string( $value ) && in_array( $value, $field['values'], true ) ) ? $value : $field['default'];

			case 'int':
				if ( is_int( $value ) || ( is_string( $value ) && 1 === preg_match( '/^-?\d{1,9}$/', $value ) ) ) {
					return max( $field['min'], min( $field['max'], (int) $value ) );
				}

				return $field['default'];

			case 'text':
				$text = is_string( $value ) ? Feed_Normalizer::plain_text( $value, $field['max'] ) : '';

				return '' !== $text ? $text : $field['default'];

			case 'bool':
				$bool = is_bool( $value ) || is_int( $value ) || is_string( $value )
					? filter_var( $value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE )
					: null;

				return $bool ?? $field['default'];
		}//end switch

		return $field['default'];
	}
}