<?php
// Everything that arrives from the Worker is checked here before any other class sees it.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class Clientsask_Validator {

	const MAX_FIXES = 50;
	const KINDS     = array( 'blog', 'meta' );

	/** A positive integer, or a short string of safe characters. Returns the id unchanged, or null. */
	public static function valid_id( $id ) {
		if ( is_int( $id ) ) {
			return $id > 0 ? $id : null;
		}
		if ( is_string( $id ) && preg_match( '/^[A-Za-z0-9_.:-]{1,64}$/', $id ) ) {
			if ( ctype_digit( $id ) && (int) $id === 0 ) {
				return null;
			}
			return $id;
		}
		return null;
	}

	/** Returns a list of clean fixes and a list of rejected ones (id may be null). */
	public static function response( $data ) {
		$result = array( 'fixes' => array(), 'rejected' => array() );
		if ( ! is_array( $data ) || ! isset( $data['fixes'] ) || ! is_array( $data['fixes'] ) ) {
			return $result;
		}
		foreach ( array_slice( array_values( $data['fixes'] ), 0, self::MAX_FIXES ) as $raw ) {
			$check = self::fix( $raw );
			if ( $check['fix'] ) {
				$result['fixes'][] = $check['fix'];
			} else {
				$result['rejected'][] = array( 'id' => $check['id'], 'reason' => $check['reason'] );
			}
		}
		return $result;
	}

	public static function fix( $raw ) {
		$bad = function ( $id, $reason ) {
			return array( 'fix' => null, 'id' => $id, 'reason' => $reason );
		};
		if ( ! is_array( $raw ) ) {
			return $bad( null, 'not an object' );
		}
		$id = self::valid_id( isset( $raw['id'] ) ? $raw['id'] : null );
		if ( $id === null ) {
			return $bad( null, 'bad id' );
		}
		$kind = isset( $raw['kind'] ) && is_string( $raw['kind'] ) ? $raw['kind'] : '';
		if ( ! in_array( $kind, self::KINDS, true ) ) {
			return $bad( $id, 'unknown kind' );
		}
		return $kind === 'blog' ? self::blog( $id, $raw ) : self::meta( $id, $raw );
	}

	private static function blog( $id, $raw ) {
		$title = Clientsask_Util::clean_text( isset( $raw['title'] ) ? $raw['title'] : '', 200 );
		$html  = isset( $raw['html'] ) && is_string( $raw['html'] ) ? Clientsask_Util::clip( $raw['html'], 200000 ) : '';
		if ( $title === '' || trim( $html ) === '' ) {
			return array( 'fix' => null, 'id' => $id, 'reason' => 'blog needs title and html' );
		}
		$slug = sanitize_title( Clientsask_Util::clean_text( isset( $raw['slug'] ) ? $raw['slug'] : '', 100 ) );
		if ( $slug === '' ) {
			$slug = sanitize_title( $title );
		}
		$faq = array();
		if ( isset( $raw['faq'] ) && is_array( $raw['faq'] ) ) {
			foreach ( array_slice( array_values( $raw['faq'] ), 0, 12 ) as $item ) {
				$q = is_array( $item ) && isset( $item['q'] ) ? Clientsask_Util::clean_text( $item['q'], 300 ) : '';
				$a = is_array( $item ) && isset( $item['a'] ) ? Clientsask_Util::clean_text( $item['a'], 1500 ) : '';
				if ( $q !== '' && $a !== '' ) {
					$faq[] = array( 'q' => $q, 'a' => $a );
				}
			}
		}
		return array(
			'fix'    => array(
				'id'              => $id,
				'kind'            => 'blog',
				'title'           => $title,
				'slug'            => $slug,
				'metaTitle'       => Clientsask_Util::clean_text( isset( $raw['metaTitle'] ) ? $raw['metaTitle'] : '', 120 ),
				'metaDescription' => Clientsask_Util::clean_text( isset( $raw['metaDescription'] ) ? $raw['metaDescription'] : '', 320 ),
				'html'            => $html,
				'faq'             => $faq,
				'jsonld'          => self::clean_jsonld( isset( $raw['jsonld'] ) ? $raw['jsonld'] : '' ),
			),
			'id'     => $id,
			'reason' => '',
		);
	}

	private static function meta( $id, $raw ) {
		$url   = Clientsask_Util::clean_text( isset( $raw['url'] ) ? $raw['url'] : '', 2000 );
		$parts = wp_parse_url( $url );
		$ok    = is_array( $parts ) && isset( $parts['scheme'], $parts['host'] ) && in_array( strtolower( $parts['scheme'] ), array( 'http', 'https' ), true );
		$title = Clientsask_Util::clean_text( isset( $raw['title'] ) ? $raw['title'] : '', 200 );
		$desc  = Clientsask_Util::clean_text( isset( $raw['description'] ) ? $raw['description'] : '', 500 );
		if ( ! $ok || $title === '' || $desc === '' ) {
			return array( 'fix' => null, 'id' => $id, 'reason' => 'meta needs url, title and description' );
		}
		return array(
			'fix'    => array( 'id' => $id, 'kind' => 'meta', 'url' => $url, 'title' => $title, 'description' => $desc ),
			'id'     => $id,
			'reason' => '',
		);
	}

	/**
	 * The FAQ JSON-LD must be JSON for one FAQPage and nothing else. Returns the re-encoded
	 * text, or '' when it is not. Used again at print time (see Clientsask_Jsonld).
	 */
	public static function clean_jsonld( $text ) {
		if ( ! is_string( $text ) || $text === '' || strlen( $text ) > 50000 ) {
			return '';
		}
		$data = json_decode( $text, true );
		if ( ! is_array( $data ) || ! isset( $data['@type'] ) || $data['@type'] !== 'FAQPage' ) {
			return '';
		}
		$out = wp_json_encode( $data, JSON_HEX_TAG | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES );
		return is_string( $out ) ? $out : '';
	}
}