<?php

namespace App\Services\ImageScan;

class ScannerText
{
    /**
     * Strip control and format characters (including ANSI escape starts and bidi overrides) and cut to $max characters.
     */
    public static function clean(mixed $value, int $max): string
    {
        if (is_int($value) || is_float($value)) {
            $value = (string) $value;
        }

        if (! is_string($value)) {
            return '';
        }

        return mb_substr(preg_replace('/[\p{Cc}\p{Cf}]/u', '', $value) ?? '', 0, $max);
    }

    /**
     * A short single-line title for a finding: the first sentence of the description, else of the related
     * description, without Markdown, URLs, or invisible characters. A description that is a package changelog
     * (Oracle Linux and similar) yields to the related description.
     */
    public static function title(?string $description, ?string $relatedDescription, string $package, string $version, string $severity): string
    {
        $own = self::looksLikeChangelog($description) ? '' : self::sentence($description);
        $text = $own ?: (self::sentence($relatedDescription) ?: self::sentence($description));

        if (count(preg_split('/\s+/u', $text, -1, PREG_SPLIT_NO_EMPTY) ?: []) < 4) {
            return self::fallbackTitle($package, $version, $severity);
        }

        return $text;
    }

    /**
     * A description that is a package changelog entry rather than a text about the vulnerability.
     */
    public static function looksLikeChangelog(?string $description): bool
    {
        $text = ltrim((string) $description);

        return str_starts_with($text, '[') || str_starts_with($text, '- ')
            || str_contains($text, 'Orabug') || str_contains($text, 'Resolves:');
    }

    /**
     * Cleans a title, also one stored before these rules: leading changelog tokens ("[1.0.9-10.0.1] - ",
     * "[3.0.7]: ", "- "), "[Orabug: …]" groups, and trailing "[CVE-…]" references. A changelog keeps its first entry
     * only. Then the label of `stripTitlePrefix()`.
     */
    public static function tidyTitle(string $text): string
    {
        $text = trim($text);
        $changelog = preg_match('/^(?:\[[^\]]*\]\s*[-:]|-)\s+/u', $text) === 1;
        $text = preg_replace('/^(?:(?:\[[^\]]*\]\s*[-:]|-)\s+)+/u', '', $text) ?? $text;
        $text = preg_replace('/\s*\[Orabug:[^\]]*\]/iu', '', $text) ?? $text;
        $text = preg_replace('/(?:\s*\[CVE-\d{4}-\d+\])+(?=\s*[.…]?\s*$)/iu', '', $text) ?? $text;
        $text = trim(preg_replace('/\s+/u', ' ', $text) ?? $text);
        if ($changelog && preg_match('/^(.+?)\s+-\s+\S/u', $text, $match) === 1) {
            $text = $match[1];
        }

        return self::stripTitlePrefix($text);
    }

    /**
     * A stored title for display: the fallback title while the stored one is a package changelog entry (until a
     * rescan parses it again), else `tidyTitle()`.
     */
    public static function storedTitle(string $title, string $package, string $version, string $severity): string
    {
        $title = trim($title);
        if ($title === '' || self::looksLikeChangelog($title)) {
            return self::fallbackTitle($package, $version, $severity);
        }

        $tidy = self::tidyTitle($title);

        return $tidy !== '' ? $tidy : self::fallbackTitle($package, $version, $severity);
    }

    /**
     * Removes the label some advisories start with ("Issue summary:", "Summary:", "Description:", "Vulnerability:"),
     * also from titles stored before the parser removed it.
     */
    public static function stripTitlePrefix(string $text): string
    {
        $stripped = preg_replace('/^(?:(?:issue\s+summary|summary|description|vulnerability)\s*:\s*)+/iu', '', $text) ?? $text;
        if ($stripped === $text) {
            return $text;
        }

        return mb_strtoupper(mb_substr($stripped, 0, 1)).mb_substr($stripped, 1);
    }

    public static function fallbackTitle(string $package, string $version, string $severity): string
    {
        $prefix = trim(preg_replace('/\s+/u', ' ', self::clean(trim($package.' '.$version), 80)) ?? '');
        $label = trim(self::clean($severity, 16));
        $label = $label !== '' ? $label : 'unknown';

        return $prefix !== '' ? "{$prefix}: {$label} vulnerability" : "{$label} vulnerability";
    }

    private static function sentence(?string $text): string
    {
        if ($text === null) {
            return '';
        }

        $text = preg_replace('/\s+/u', ' ', $text) ?? '';
        $text = self::clean($text, 2000);
        $text = preg_replace('/!?\[([^\]]*)\]\([^)\s]*\)/u', '$1', $text) ?? '';
        $text = preg_replace('~\(\s*(?:https?|ftp)://[^\s()]*\s*\)~iu', '', $text) ?? '';
        $text = preg_replace_callback(
            '~(?:https?|ftp)://\S+|\bwww\.\S+~iu',
            fn (array $match): string => substr($match[0], strlen(rtrim($match[0], '.,;:)'))),
            $text,
        ) ?? '';
        $text = preg_replace('/(?<!\w)(\*\*|~~)(?=\S)(.+?)(?<=\S)\1(?!\w)/u', '$2', $text) ?? '';
        $text = preg_replace('/(?<!\w)__(?=\S)([^_]*?\s[^_]*?)(?<=\S)__(?!\w)/u', '$1', $text) ?? '';
        $text = preg_replace('/`(?=\S)([^`]*?)(?<=\S)`/u', '$1', $text) ?? '';
        $text = preg_replace('/^(?:#{1,6}|>)\s+/u', '', $text) ?? '';
        $text = self::tidyTitle(trim(preg_replace('/\s+/u', ' ', $text) ?? ''));

        if (preg_match('/^(.*?(?i:(?<!\be\.g)(?<!\bi\.e))[.!?])\s+\p{Lu}/su', $text, $match) === 1) {
            $text = $match[1];
        }

        if (mb_strlen($text) <= 120) {
            return $text;
        }

        $cut = mb_substr($text, 0, 119);
        $space = mb_strrpos($cut, ' ');
        if ($space !== false && $space > 0) {
            $cut = mb_substr($cut, 0, $space);
        }

        return rtrim($cut, " \t,;:.-").'…';
    }
}