<?php
namespace CacheShark;

defined( 'ABSPATH' ) || exit;

/** Option storage, sanitising, and the config file read by the drop-in. */
class Settings {

	const OPTION = 'cache_shark_settings';

	public static function defaults(): array {
		return array(
			'enabled'         => 1,
			'ttl_hours'       => 10, // Keep < 12h: WordPress nonces stay valid 12-24h.
			'separate_mobile' => 0,
			'preload'         => 1,
			'lazy_images'     => 0,
			'lazy_iframes'    => 0,
			'lazy_skip_first' => 2,
			'lazy_exclude'    => array(),
			'exclude_urls'    => array(),
			'exclude_cookies' => array(),
		);
	}

	public static function get(): array {
		return wp_parse_args( (array) get_option( self::OPTION, array() ), self::defaults() );
	}

	/** register_setting() sanitize callback. Never trust input. */
	public static function sanitize( $input ): array {
		$input = is_array( $input ) ? $input : array();
		$lines = static function ( $value ) {
			if ( is_array( $value ) ) {
				$value = implode( "\n", $value ); // Already-sanitised input: sanitising twice must be harmless.
			}
			$out = array();
			foreach ( preg_split( '/\R/', (string) $value ) as $line ) {
				$line = trim( sanitize_text_field( $line ) );
				if ( '' !== $line ) {
					$out[] = $line;
				}
			}
			return array_values( array_unique( $out ) );
		};
		$urls = array_map(
			static function ( $u ) {
				return '/' === $u[0] ? $u : '/' . $u;
			},
			$lines( $input['exclude_urls'] ?? '' )
		);
		return array(
			'enabled'         => empty( $input['enabled'] ) ? 0 : 1,
			'ttl_hours'       => max( 0, min( 720, (int) ( $input['ttl_hours'] ?? 10 ) ) ),
			'separate_mobile' => empty( $input['separate_mobile'] ) ? 0 : 1,
			'preload'         => empty( $input['preload'] ) ? 0 : 1,
			'lazy_images'     => empty( $input['lazy_images'] ) ? 0 : 1,
			'lazy_iframes'    => empty( $input['lazy_iframes'] ) ? 0 : 1,
			'lazy_skip_first' => max( 0, min( 20, (int) ( $input['lazy_skip_first'] ?? 2 ) ) ),
			'lazy_exclude'    => $lines( $input['lazy_exclude'] ?? '' ),
			'exclude_urls'    => $urls,
			'exclude_cookies' => $lines( $input['exclude_cookies'] ?? '' ),
		);
	}

	/** Write config.php for the drop-in (atomic). */
	public static function write_config(): bool {
		$s   = self::get();
		$cfg = array(
			'enabled'         => (bool) $s['enabled'],
			'ttl'             => (int) $s['ttl_hours'] * HOUR_IN_SECONDS,
			'separate_mobile' => (bool) $s['separate_mobile'],
			'exclude_urls'    => array_values( $s['exclude_urls'] ),
			'exclude_cookies' => array_values( $s['exclude_cookies'] ),
		);
		$json = wp_json_encode( $cfg );
		if ( false === $json ) {
			return false;
		}
		// Nowdoc: the JSON is never parsed as PHP, so no user-entered text can run as code.
		return CacheStore::write_file(
			CACHE_SHARK_BASE . '/config.php',
			"<?php\ndefined( 'ABSPATH' ) || exit;\nreturn json_decode(\n<<<'JSON'\n" . $json . "\nJSON\n, true );\n"
		);
	}
}