<?php
declare(strict_types=1);

function ensure_blog_schema(): void
{
    db()->exec(
        "CREATE TABLE IF NOT EXISTS blog_posts (
            id BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
            title VARCHAR(255) NOT NULL,
            slug VARCHAR(220) NOT NULL,
            category VARCHAR(120) DEFAULT NULL,
            excerpt TEXT DEFAULT NULL,
            content MEDIUMTEXT NOT NULL,
            featured_image VARCHAR(500) DEFAULT NULL,
            status VARCHAR(20) NOT NULL DEFAULT 'draft',
            publish_at DATETIME DEFAULT NULL,
            seo_title VARCHAR(255) DEFAULT NULL,
            seo_description VARCHAR(320) DEFAULT NULL,
            created_by_user_id INT UNSIGNED DEFAULT NULL,
            updated_by_user_id INT UNSIGNED DEFAULT NULL,
            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
            UNIQUE KEY uq_blog_slug (slug),
            INDEX idx_blog_public (status,publish_at),
            INDEX idx_blog_publish (publish_at,id),
            CONSTRAINT fk_blog_created_by FOREIGN KEY (created_by_user_id) REFERENCES users(id) ON DELETE SET NULL,
            CONSTRAINT fk_blog_updated_by FOREIGN KEY (updated_by_user_id) REFERENCES users(id) ON DELETE SET NULL
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_polish_ci"
    );
}

function blog_promote_due_posts(): int
{
    ensure_blog_schema();
    $now = date('Y-m-d H:i:s');
    $stmt = db()->prepare(
        "UPDATE blog_posts
         SET status='published', updated_at=NOW()
         WHERE status='scheduled'
           AND publish_at IS NOT NULL
           AND publish_at<=?"
    );
    $stmt->execute([$now]);
    return $stmt->rowCount();
}

function blog_slugify(string $value): string
{
    $value = trim($value);
    if ($value === '') return 'wpis';

    $ascii = iconv('UTF-8','ASCII//TRANSLIT//IGNORE',$value);
    if ($ascii !== false) $value = $ascii;
    $value = strtolower($value);
    $value = preg_replace('/[^a-z0-9]+/','-',$value) ?? 'wpis';
    $value = trim($value,'-');
    return $value !== '' ? mb_substr($value,0,210,'UTF-8') : 'wpis';
}

function blog_unique_slug(string $slug, int $excludeId = 0): string
{
    ensure_blog_schema();
    $base = blog_slugify($slug);
    $candidate = $base;
    $i = 2;

    while (true) {
        $stmt = db()->prepare('SELECT id FROM blog_posts WHERE slug=? AND id<>? LIMIT 1');
        $stmt->execute([$candidate,$excludeId]);
        if (!$stmt->fetch()) return $candidate;
        $candidate = mb_substr($base,0,195,'UTF-8') . '-' . $i;
        $i++;
    }
}

function blog_excerpt_from_content(string $content, int $max = 180): string
{
    $plain = trim(preg_replace('/\s+/u',' ',$content) ?? $content);
    if (mb_strlen($plain,'UTF-8') <= $max) return $plain;
    return rtrim(mb_substr($plain,0,$max-1,'UTF-8')) . '…';
}

function blog_public_posts(int $limit = 100): array
{
    ensure_blog_schema();
    blog_promote_due_posts();
    $limit = max(1,min(500,$limit));

    return db()->query(
        "SELECT * FROM blog_posts
         WHERE status='published'
           AND publish_at IS NOT NULL
           AND publish_at<=NOW()
         ORDER BY publish_at DESC,id DESC
         LIMIT $limit"
    )->fetchAll();
}

function blog_public_post_by_slug(string $slug, bool $allowPreview = false): ?array
{
    ensure_blog_schema();
    blog_promote_due_posts();

    if ($allowPreview) {
        $stmt = db()->prepare('SELECT * FROM blog_posts WHERE slug=? LIMIT 1');
        $stmt->execute([$slug]);
        return $stmt->fetch() ?: null;
    }

    $stmt = db()->prepare(
        "SELECT * FROM blog_posts
         WHERE slug=?
           AND status='published'
           AND publish_at IS NOT NULL
           AND publish_at<=NOW()
         LIMIT 1"
    );
    $stmt->execute([$slug]);
    return $stmt->fetch() ?: null;
}

function blog_post_by_id(int $id): ?array
{
    ensure_blog_schema();
    $stmt = db()->prepare('SELECT * FROM blog_posts WHERE id=? LIMIT 1');
    $stmt->execute([$id]);
    return $stmt->fetch() ?: null;
}

function blog_status_label(array $post): string
{
    $status = (string)($post['status'] ?? 'draft');
    if ($status === 'scheduled') return 'Zaplanowany';
    if ($status === 'published') return 'Opublikowany';
    return 'Szkic';
}

function blog_can_manage(): bool
{
    $u = admin_user();
    return $u && in_array((string)$u['role'],['admin','editor'],true);
}

function require_blog_manager(): array
{
    require_login();
    $u = admin_user();
    if (!$u || !in_array((string)$u['role'],['admin','editor'],true)) {
        http_response_code(403);
        exit('Brak dostępu do bloga.');
    }
    return $u;
}

function blog_upload_featured_image(array $file): string
{
    $error = (int)($file['error'] ?? UPLOAD_ERR_NO_FILE);
    if ($error === UPLOAD_ERR_NO_FILE) return '';
    if ($error !== UPLOAD_ERR_OK) throw new RuntimeException('Błąd wysyłania zdjęcia.');

    $tmp = (string)($file['tmp_name'] ?? '');
    $size = (int)($file['size'] ?? 0);
    if (!is_uploaded_file($tmp)) throw new RuntimeException('Nieprawidłowy upload zdjęcia.');
    if ($size > 12*1024*1024) throw new RuntimeException('Zdjęcie jest za duże. Maks. 12 MB.');

    $mime = (new finfo(FILEINFO_MIME_TYPE))->file($tmp);
    $map = [
        'image/jpeg'=>'jpg',
        'image/png'=>'png',
        'image/webp'=>'webp',
        'image/avif'=>'avif',
    ];
    if (!isset($map[$mime])) throw new RuntimeException('Dozwolone zdjęcia: JPG, PNG, WEBP, AVIF.');

    $dir = dirname(__DIR__) . '/assets/img/blog';
    if (!is_dir($dir) && !mkdir($dir,0755,true) && !is_dir($dir)) {
        throw new RuntimeException('Nie udało się utworzyć katalogu bloga.');
    }

    $name = date('Ymd-His') . '-' . bin2hex(random_bytes(5)) . '.' . $map[$mime];
    if (!move_uploaded_file($tmp,$dir.'/'.$name)) throw new RuntimeException('Nie udało się zapisać zdjęcia.');
    @chmod($dir.'/'.$name,0644);
    return '/assets/img/blog/' . $name;
}

function blog_render_content(string $content): string
{
    $lines = preg_split('/\R/u',trim($content)) ?: [];
    $html = [];
    $paragraph = [];
    $list = [];

    $flushParagraph = function() use (&$paragraph,&$html): void {
        if (!$paragraph) return;
        $html[] = '<p>' . nl2br(e(implode("\n",$paragraph))) . '</p>';
        $paragraph = [];
    };
    $flushList = function() use (&$list,&$html): void {
        if (!$list) return;
        $items = array_map(fn($x)=>'<li>'.e($x).'</li>',$list);
        $html[] = '<ul>' . implode('',$items) . '</ul>';
        $list = [];
    };

    foreach ($lines as $line) {
        $trim = trim($line);
        if ($trim === '') {
            $flushParagraph();
            $flushList();
            continue;
        }
        if (str_starts_with($trim,'## ')) {
            $flushParagraph(); $flushList();
            $html[] = '<h2>' . e(trim(substr($trim,3))) . '</h2>';
            continue;
        }
        if (str_starts_with($trim,'### ')) {
            $flushParagraph(); $flushList();
            $html[] = '<h3>' . e(trim(substr($trim,4))) . '</h3>';
            continue;
        }
        if (str_starts_with($trim,'- ')) {
            $flushParagraph();
            $list[] = trim(substr($trim,2));
            continue;
        }
        $flushList();
        $paragraph[] = $trim;
    }
    $flushParagraph();
    $flushList();
    return implode("\n",$html);
}

function blog_public_enabled(): bool
{
    return setting('nav_blog_enabled','0') === '1';
}