<?php
/**
 * Small shared helpers.
 *
 * @package FlareOps
 */

namespace FlareOps;

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

final class Util {

	/** AI sources for referral attribution: match string => normalized source name. */
	public const AI_SOURCES = array(
		'chatgpt.com'           => 'chatgpt',
		'openai.com'            => 'chatgpt',
		'perplexity.ai'         => 'perplexity',
		'gemini.google.com'     => 'gemini',
		'copilot.microsoft.com' => 'copilot',
		'bing.com/chat'         => 'copilot',
		'claude.ai'             => 'claude',
		'you.com'               => 'you',
		'meta.ai'               => 'meta-ai',
		'deepseek.com'          => 'deepseek',
		'grok.com'              => 'grok',
	);

	/**
	 * Run a callable and swallow any error so a failure never takes the site down.
	 *
	 * @param callable $fn       Work.
	 * @param mixed    $fallback Returned on failure.
	 * @return mixed
	 */
	public static function safe( callable $fn, $fallback = null ) {
		try {
			return $fn();
		} catch ( \Throwable $e ) {
			self::log( $e->getMessage() . ' @ ' . basename( $e->getFile() ) . ':' . $e->getLine() );
			return $fallback;
		}
	}

	/** Wrap a hook callback in safe(). */
	public static function guard( callable $fn ): \Closure {
		return static function ( ...$args ) use ( $fn ) {
			$first = $args[0] ?? null;
			try {
				return $fn( ...$args );
			} catch ( \Throwable $e ) {
				self::log( $e->getMessage() . ' @ ' . basename( $e->getFile() ) . ':' . $e->getLine() );
				return $first; // For filters, pass the value through unchanged.
			}
		};
	}

	public static function log( string $msg ): void {
		if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
			error_log( 'flareOps: ' . $msg ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions
		}
	}

	/* ---------- request headers ($_SERVER): sanitized and validated in one place ---------- */

	/** A $_SERVER value as a single-line string (tags, control characters and line breaks removed). */
	public static function server_text( string $key, int $max = 512 ): string {
		if ( ! isset( $_SERVER[ $key ] ) || ! is_string( $_SERVER[ $key ] ) ) {
			return '';
		}
		$v = (string) preg_replace( '/[\x00-\x1F\x7F]/', '', sanitize_text_field( wp_unslash( $_SERVER[ $key ] ) ) );
		return mb_substr( $v, 0, $max );
	}

	/** A $_SERVER value that must be an IP address ('' if it is not one). */
	public static function server_ip( string $key ): string {
		$ip = self::server_text( $key, 64 );
		if ( 'HTTP_X_FORWARDED_FOR' === $key ) {
			$ip = trim( explode( ',', $ip )[0] ); // The first entry is the client.
		}
		$ip = filter_var( $ip, FILTER_VALIDATE_IP );
		return false === $ip ? '' : $ip;
	}

	/** The request path (no query string or fragment), starting with "/". */
	public static function request_path(): string {
		if ( ! isset( $_SERVER['REQUEST_URI'] ) || ! is_string( $_SERVER['REQUEST_URI'] ) ) {
			return '/';
		}
		// esc_url_raw, not sanitize_text_field: that would strip the %XX of non-ASCII paths (e.g. Hebrew URLs).
		$uri  = esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ), array( 'http', 'https' ) );
		$path = (string) wp_parse_url( $uri, PHP_URL_PATH );
		$path = (string) preg_replace( '#[^A-Za-z0-9/%._~!$&\'()*+,;=:@-]#', '', $path );
		return ( '' === $path || '/' !== $path[0] ) ? '/' : mb_substr( $path, 0, 255 );
	}

	public static function woo_active(): bool {
		return class_exists( '\WooCommerce' ) && function_exists( 'wc_get_product' );
	}

	public static function iso( $ts = null ): string {
		return gmdate( 'Y-m-d\TH:i:s\Z', null === $ts ? time() : (int) $ts );
	}

	/** Convert stored UTC MySQL datetime to ISO 8601. */
	public static function mysql_to_iso( ?string $dt ): ?string {
		if ( ! $dt ) {
			return null;
		}
		$ts = strtotime( $dt . ' UTC' );
		return false === $ts ? null : self::iso( $ts );
	}

	/** HTML -> plain text, decoded, whitespace collapsed. */
	public static function plain_text( $html ): string {
		$html = (string) $html;
		if ( function_exists( 'strip_shortcodes' ) ) {
			$html = strip_shortcodes( $html );
		}
		// Leftover shortcodes of inactive plugins / page builders ([vc_row], [et_pb_text admin_label="x"], [/foo]).
		// Plain bracketed words such as "[New]" or "[2 pack]" are kept.
		$html = (string) preg_replace( '#\[/?[a-z][a-z0-9]*[_\-][a-z0-9_\-]*(?:\s[^\]]*)?\]|\[/[a-z][a-z0-9_\-]*\]|\[[a-z][a-z0-9_\-]*\s+[^\]]*=[^\]]*\]#i', ' ', $html );
		$html = preg_replace( '#<(script|style)[^>]*>.*?</\1>#is', ' ', $html );
		$html = preg_replace( '#<(br|/p|/div|/li|/h[1-6])[^>]*>#i', "\n", (string) $html );
		$text = wp_strip_all_tags( (string) $html );
		$text = html_entity_decode( $text, ENT_QUOTES | ENT_HTML5, 'UTF-8' );
		$text = preg_replace( "/[ \t\x{00A0}]+/u", ' ', $text );
		$text = preg_replace( "/\s*\n\s*/", "\n", (string) $text );
		return trim( (string) $text );
	}

	/** scheme://host[:port]/path only: query strings and fragments (tokens, emails, chat IDs) are dropped. */
	public static function strip_url_query( string $url ): string {
		$url = trim( $url );
		if ( '' === $url ) {
			return '';
		}
		$p = wp_parse_url( $url );
		if ( ! is_array( $p ) || empty( $p['host'] ) ) {
			return (string) preg_replace( '/[?#].*$/s', '', $url );
		}
		$scheme = isset( $p['scheme'] ) ? strtolower( $p['scheme'] ) . '://' : '//';
		$port   = isset( $p['port'] ) ? ':' . (int) $p['port'] : '';
		return $scheme . strtolower( $p['host'] ) . $port . ( $p['path'] ?? '' );
	}

	/** Salted SHA-256 of an order ID (salt: random per-site option). The API never returns raw order IDs. */
	public static function order_ref( int $order_id ): string {
		$salt = (string) get_option( 'flareops_order_salt', '' );
		if ( '' === $salt ) {
			$salt = bin2hex( random_bytes( 32 ) );
			update_option( 'flareops_order_salt', $salt, false );
		}
		return hash( 'sha256', $salt . '|' . $order_id );
	}

	/**
	 * Validate a GTIN (GTIN-8/12/13/14) including the GS1 check digit.
	 *
	 * @param string $gtin Digits only.
	 */
	public static function is_valid_gtin( string $gtin ): bool {
		if ( ! preg_match( '/^(\d{8}|\d{12}|\d{13}|\d{14})$/', $gtin ) ) {
			return false;
		}
		$digits = str_split( $gtin );
		$check  = (int) array_pop( $digits );
		$digits = array_reverse( $digits );
		$sum    = 0;
		foreach ( $digits as $i => $d ) {
			$sum += (int) $d * ( 0 === $i % 2 ? 3 : 1 );
		}
		return ( ( 10 - ( $sum % 10 ) ) % 10 ) === $check;
	}

	/** Strip spaces and hyphens from a GTIN candidate. */
	public static function normalize_gtin( string $gtin ): string {
		return preg_replace( '/[\s\-]/', '', trim( $gtin ) );
	}

	/**
	 * Classify a referrer and/or utm_source as an AI app.
	 *
	 * @return string|null Normalized source name or null.
	 */
	public static function ai_source( string $referrer, string $utm = '' ): ?string {
		$candidates = array();
		if ( '' !== $referrer ) {
			$parts = wp_parse_url( $referrer );
			if ( is_array( $parts ) && ! empty( $parts['host'] ) ) {
				$host         = strtolower( preg_replace( '/^www\./i', '', $parts['host'] ) );
				$candidates[] = $host . ( $parts['path'] ?? '' );
			}
		}
		if ( '' !== $utm ) {
			$candidates[] = strtolower( $utm );
		}
		foreach ( $candidates as $c ) {
			foreach ( self::AI_SOURCES as $needle => $name ) {
				if ( str_contains( $needle, '/' ) ) {
					if ( str_starts_with( $c, $needle ) ) {
						return $name;
					}
					continue;
				}
				// Host match: exact or subdomain. utm_source may be "chatgpt.com" or "chatgpt".
				if ( $c === $needle || str_ends_with( explode( '/', $c )[0], '.' . $needle ) || str_starts_with( $c, $needle . '/' ) ) {
					return $name;
				}
			}
			// Bare utm names such as "chatgpt", "perplexity".
			if ( in_array( $c, array_unique( array_values( self::AI_SOURCES ) ), true ) ) {
				return $c;
			}
		}
		return null;
	}
}