<?php

namespace App\Support;

class WooHtml
{
    private const ALLOWED_TAGS = '<p><br><strong><b><em><i><ul><ol><li><a>';

    public static function sanitize(mixed $value): ?string
    {
        if ($value === null) {
            return null;
        }

        $html = trim((string) $value);
        if ($html === '') {
            return null;
        }

        if ($html === strip_tags($html)) {
            return self::plainToHtml($html);
        }

        $clean = trim(strip_tags($html, self::ALLOWED_TAGS));

        return $clean === '' ? null : $clean;
    }

    public static function normalizeForEditor(?string $value): string
    {
        if ($value === null || trim($value) === '') {
            return '';
        }

        if ($value === strip_tags($value)) {
            return self::plainToHtml($value) ?? '';
        }

        return $value;
    }

    public static function plainToHtml(string $plain): ?string
    {
        $plain = str_replace(["\r\n", "\r"], "\n", trim($plain));
        if ($plain === '') {
            return null;
        }

        $parts = preg_split("/\n\s*\n/", $plain) ?: [];
        if (count($parts) === 1 && str_contains($plain, "\n")) {
            $parts = explode("\n", $plain);
        }

        $paragraphs = array_values(array_filter(
            array_map('trim', $parts),
            fn (string $part) => $part !== '',
        ));

        if ($paragraphs === []) {
            return null;
        }

        return implode('', array_map(
            fn (string $paragraph) => '<p>'.self::escape($paragraph).'</p>',
            $paragraphs,
        ));
    }

    private static function escape(string $text): string
    {
        return htmlspecialchars($text, ENT_QUOTES | ENT_HTML5, 'UTF-8');
    }
}