<?php
namespace AfFulltext;

/**
 * Plain HTTP GET via cURL.
 *
 * Used by the CLI harness. Inside tt-rss the `direct` backend is TtrssFetcher
 * instead, so article fetches keep tt-rss's own SSRF guard (UrlHelper::validate).
 */
final class CurlFetcher implements Fetcher {
	public function __construct(
		private readonly int $timeout = 20,
		private readonly string $user_agent = 'Mozilla/5.0 (compatible; af_fulltext/1.0; +https://tt-rss.org/)',
	) {}

	public function name(): string { return 'direct'; }

	public function fetch(string $url, array $headers = []): FetchResult {
		$ch = curl_init();

		$hdr = [];
		foreach ($headers as $k => $v) $hdr[] = "$k: $v";

		curl_setopt_array($ch, [
			CURLOPT_URL => $url,
			CURLOPT_RETURNTRANSFER => true,
			CURLOPT_FOLLOWLOCATION => true,
			CURLOPT_MAXREDIRS => 8,
			CURLOPT_TIMEOUT => $this->timeout,
			CURLOPT_CONNECTTIMEOUT => 10,
			CURLOPT_ENCODING => '',
			CURLOPT_USERAGENT => $headers['user-agent'] ?? $this->user_agent,
			CURLOPT_HTTPHEADER => $hdr,
		]);

		$body = curl_exec($ch);
		$err = curl_error($ch);
		$status = (int) curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
		$effective = (string) curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
		$content_type = (string) curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
		curl_close($ch);

		if ($err !== '' || !is_string($body))
			return new FetchResult(error: $err !== '' ? $err : 'empty response', status: $status, effective_url: $effective ?: $url);

		if ($status >= 400)
			return new FetchResult(error: "HTTP $status", status: $status, effective_url: $effective ?: $url);

		return new FetchResult(
			html: self::to_utf8($body, $content_type),
			effective_url: $effective ?: $url,
			status: $status,
		);
	}

	/**
	 * Normalise to UTF-8. Several of these feeds are Polish, and a page served as
	 * ISO-8859-2 that is treated as UTF-8 loses every accented character.
	 */
	public static function to_utf8(string $body, string $content_type): string {
		$charset = '';

		if (preg_match('/charset=["\']?([\w-]+)/i', $content_type, $m)) $charset = $m[1];

		if ($charset === '' && preg_match('/<meta[^>]+charset=["\']?([\w-]+)/i', substr($body, 0, 4096), $m))
			$charset = $m[1];

		if ($charset === '' || preg_match('/^utf-?8$/i', $charset)) return $body;

		$converted = @mb_convert_encoding($body, 'UTF-8', $charset);

		return is_string($converted) && $converted !== '' ? $converted : $body;
	}
}