<?php

if (!defined('ABSPATH')) {
	exit;
}

final class LeExport_Link_Extractor {
	/**
	 * Extracts URLs from HTML content.
	 *
	 * @return string[] List of normalized URLs.
	 */
	public static function extract_from_html(string $html): array {
		if ($html === '') {
			return [];
		}

		$urls = [];

		// Fast path: regex extraction of href/src attributes.
		// Keep it conservative to avoid pathological regex backtracking.
		if (preg_match_all('~\b(?:href|src)\s*=\s*(["\'])(.*?)\1~i', $html, $m)) {
			foreach ($m[2] as $u) {
				$urls[] = (string)$u;
			}
		}

		// Also pick up bare URLs in text (optional).
		if (preg_match_all('~https?://[^\s<>"\']+~i', $html, $m2)) {
			foreach ($m2[0] as $u) {
				$urls[] = (string)$u;
			}
		}

		$clean = [];
		foreach ($urls as $u) {
			$u = trim(html_entity_decode($u, ENT_QUOTES, get_bloginfo('charset') ?: 'UTF-8'));
			if ($u === '' || strpos($u, 'javascript:') === 0 || strpos($u, 'mailto:') === 0 || strpos($u, 'tel:') === 0) {
				continue;
			}

			// Drop fragments for link-checking.
			$u = preg_replace('~#.*$~', '', $u);
			$u = trim((string)$u);
			if ($u === '') {
				continue;
			}

			$clean[] = $u;
		}

		$clean = array_values(array_unique($clean));
		sort($clean);
		return $clean;
	}

	public static function is_http_url(string $url): bool {
		return (bool)preg_match('~^https?://~i', $url);
	}

	public static function normalize_to_absolute(string $url, string $base): string {
		$url = trim($url);
		if ($url === '') {
			return '';
		}

		if (self::is_http_url($url)) {
			return $url;
		}

		// Protocol-relative.
		if (strpos($url, '//') === 0) {
			$scheme = wp_parse_url($base, PHP_URL_SCHEME) ?: 'https';
			return $scheme . ':' . $url;
		}

		// Root-relative.
		if (strpos($url, '/') === 0) {
			$origin = self::origin($base);
			return $origin ? ($origin . $url) : $url;
		}

		// Relative path.
		$origin = self::origin($base);
		$path = wp_parse_url($base, PHP_URL_PATH);
		if ($origin && is_string($path)) {
			$dir = preg_replace('~/[^/]*$~', '/', $path);
			return $origin . $dir . $url;
		}

		return $url;
	}

	public static function origin(string $url): string {
		$scheme = wp_parse_url($url, PHP_URL_SCHEME);
		$host = wp_parse_url($url, PHP_URL_HOST);
		$port = wp_parse_url($url, PHP_URL_PORT);
		if (!is_string($scheme) || !is_string($host) || $scheme === '' || $host === '') {
			return '';
		}
		$o = $scheme . '://' . $host;
		if (is_int($port) && $port > 0) {
			$o .= ':' . $port;
		}
		return $o;
	}

	public static function is_internal(string $url): bool {
		$home = home_url('/');
		$home_origin = self::origin($home);
		$u_origin = self::origin($url);
		return $home_origin !== '' && $u_origin !== '' && strtolower($home_origin) === strtolower($u_origin);
	}
}