<?php

declare(strict_types=1);

if (session_status() !== PHP_SESSION_ACTIVE) {
    session_start();
}

require_once __DIR__ . '/../db/config.php';

function library_bootstrap(): void
{
    static $booted = false;
    if ($booted) {
        return;
    }

    $migrationPath = __DIR__ . '/../db/migrations/001_library_documents.sql';
    if (is_file($migrationPath)) {
        $sql = file_get_contents($migrationPath);
        if (is_string($sql) && trim($sql) !== '') {
            db()->exec($sql);
        }
    }

    // Run new migrations if needed
    $migration2Path = __DIR__ . '/../db/migrations/002_add_library_metadata.sql';
    if (is_file($migration2Path)) {
        // Simple check if columns exist
        $exists = db()->query("SHOW COLUMNS FROM library_documents LIKE 'category_ar'")->fetch();
        if (!$exists) {
            $sql = file_get_contents($migration2Path);
            db()->exec($sql);
        }
    }

    $migration3Path = __DIR__ . '/../db/migrations/003_normalize_categories.sql';
    if (is_file($migration3Path)) {
        // Simple check if table exists
        $exists = db()->query("SHOW TABLES LIKE 'library_categories'")->fetch();
        if (!$exists) {
            $sql = file_get_contents($migration3Path);
            db()->exec($sql);
        }
    }

    $uploadDir = __DIR__ . '/../uploads/library';
    if (!is_dir($uploadDir)) {
        mkdir($uploadDir, 0775, true);
    }

    library_seed_demo_documents();
    $booted = true;
}

function h(?string $value): string
{
    return htmlspecialchars((string) $value, ENT_QUOTES, 'UTF-8');
}

function library_project_meta(): array
{
    return [
        'name' => $_SERVER['PROJECT_NAME'] ?? 'Nabd Library',
        'description' => $_SERVER['PROJECT_DESCRIPTION'] ?? 'Bilingual electronic library for Arabic and English documents, online reading, and AI-assisted summaries.',
        'image' => $_SERVER['PROJECT_IMAGE_URL'] ?? '',
    ];
}

function library_set_flash(string $type, string $message): void
{
    $_SESSION['library_flash'][] = ['type' => $type, 'message' => $message];
}

function library_get_flashes(): array
{
    $flashes = $_SESSION['library_flash'] ?? [];
    unset($_SESSION['library_flash']);
    return is_array($flashes) ? $flashes : [];
}

function library_seed_demo_documents(): void
{
    $count = (int) (db()->query('SELECT COUNT(*) FROM library_documents')->fetchColumn() ?: 0);
    if ($count > 0) {
        return;
    }

    $pdfRelative = 'uploads/library/demo-library-guide.pdf';
    $txtRelative = 'uploads/library/demo-bilingual-notes.txt';
    $pdfAbsolute = __DIR__ . '/../' . $pdfRelative;
    $txtAbsolute = __DIR__ . '/../' . $txtRelative;
}

function library_old(string $key, string $default = ''): string
{
    return isset($_POST[$key]) ? trim((string) $_POST[$key]) : $default;
}

function library_document_type_label(string $type): string
{
    $map = [
        'pdf' => 'PDF reader',
        'txt' => 'Text note',
        'doc' => 'Word document',
        'docx' => 'Word document',
        'ppt' => 'PowerPoint',
        'pptx' => 'PowerPoint',
    ];
    return $map[strtolower($type)] ?? strtoupper($type);
}

function library_language_label(string $lang): string
{
    $map = [
        'en' => 'English',
        'ar' => 'Arabic',
        'bilingual' => 'Bilingual',
    ];
    return $map[$lang] ?? 'Unknown';
}

function library_visibility_label(string $visibility): string
{
    return $visibility === 'private' ? 'Private / login' : 'Public';
}

function library_allowed_extensions(): array
{
    return [
        'pdf' => 'PDF reader',
        'txt' => 'Text note',
        'doc' => 'Word document',
        'docx' => 'Word document',
        'ppt' => 'PowerPoint',
        'pptx' => 'PowerPoint',
    ];
}

// --- Category Functions ---

function library_get_categories(): array
{
    library_bootstrap();
    $stmt = db()->query('SELECT * FROM library_categories ORDER BY name_en ASC');
    return $stmt ? $stmt->fetchAll() : [];
}

function library_get_subcategories(?int $categoryId = null): array
{
    library_bootstrap();
    if ($categoryId !== null) {
        $stmt = db()->prepare('SELECT * FROM library_subcategories WHERE category_id = ? ORDER BY name_en ASC');
        $stmt->execute([$categoryId]);
        return $stmt->fetchAll() ?: [];
    }
    $stmt = db()->query('SELECT * FROM library_subcategories ORDER BY name_en ASC');
    return $stmt ? $stmt->fetchAll() : [];
}

function library_create_category(string $nameEn, string $nameAr): int
{
    library_bootstrap();
    $stmt = db()->prepare('INSERT INTO library_categories (name_en, name_ar) VALUES (?, ?)');
    $stmt->execute([$nameEn, $nameAr]);
    return (int) db()->lastInsertId();
}

function library_create_subcategory(int $categoryId, string $nameEn, string $nameAr): int
{
    library_bootstrap();
    $stmt = db()->prepare('INSERT INTO library_subcategories (category_id, name_en, name_ar) VALUES (?, ?, ?)');
    $stmt->execute([$categoryId, $nameEn, $nameAr]);
    return (int) db()->lastInsertId();
}

function library_get_category_by_id(int $id): ?array
{
    library_bootstrap();
    $stmt = db()->prepare('SELECT * FROM library_categories WHERE id = ?');
    $stmt->execute([$id]);
    return $stmt->fetch() ?: null;
}

function library_get_subcategory_by_id(int $id): ?array
{
    library_bootstrap();
    $stmt = db()->prepare('SELECT * FROM library_subcategories WHERE id = ?');
    $stmt->execute([$id]);
    return $stmt->fetch() ?: null;
}

function library_update_category(int $id, string $nameEn, string $nameAr): void
{
    library_bootstrap();
    $stmt = db()->prepare('UPDATE library_categories SET name_en = ?, name_ar = ? WHERE id = ?');
    $stmt->execute([$nameEn, $nameAr, $id]);
}

function library_delete_category(int $id): void
{
    library_bootstrap();
    $stmt = db()->prepare('DELETE FROM library_categories WHERE id = ?');
    $stmt->execute([$id]);
}

function library_update_subcategory(int $id, int $categoryId, string $nameEn, string $nameAr): void
{
    library_bootstrap();
    $stmt = db()->prepare('UPDATE library_subcategories SET category_id = ?, name_en = ?, name_ar = ? WHERE id = ?');
    $stmt->execute([$categoryId, $nameEn, $nameAr, $id]);
}

function library_delete_subcategory(int $id): void
{
    library_bootstrap();
    $stmt = db()->prepare('DELETE FROM library_subcategories WHERE id = ?');
    $stmt->execute([$id]);
}

// --- End Category Functions ---

function library_fetch_documents(bool $publicOnly = false, array $filters = []): array
{
    library_bootstrap();

    $sql = 'SELECT d.*, c.name_en as cat_en, c.name_ar as cat_ar, sc.name_en as sub_en, sc.name_ar as sub_ar 
            FROM library_documents d 
            LEFT JOIN library_categories c ON d.category_id = c.id
            LEFT JOIN library_subcategories sc ON d.subcategory_id = sc.id
            WHERE 1=1';
    $params = [];

    if ($publicOnly) {
        $sql .= ' AND d.visibility = :visibility';
        $params[':visibility'] = 'public';
    }

    $sql .= ' ORDER BY d.is_featured DESC, d.created_at DESC';
    $stmt = db()->prepare($sql);
    foreach ($params as $key => $value) {
        $stmt->bindValue($key, $value);
    }
    $stmt->execute();

    return $stmt->fetchAll() ?: [];
}

function library_recent_documents(int $limit = 3, bool $publicOnly = false): array
{
    library_bootstrap();

    $sql = 'SELECT * FROM library_documents WHERE 1=1';
    if ($publicOnly) {
        $sql .= ' AND visibility = "public"';
    }
    $sql .= ' ORDER BY created_at DESC LIMIT ' . (int)$limit;

    $stmt = db()->query($sql);
    return $stmt ? $stmt->fetchAll() : [];
}

function library_catalog_metrics(): array
{
    library_bootstrap();

    $sql = 'SELECT
        COUNT(*) AS total_count,
        SUM(CASE WHEN visibility = "public" THEN 1 ELSE 0 END) AS public_count,
        SUM(CASE WHEN visibility = "private" THEN 1 ELSE 0 END) AS private_count,
        SUM(CASE WHEN summary_text IS NOT NULL THEN 1 ELSE 0 END) AS summarized_count
    FROM library_documents';

    $row = db()->query($sql)->fetch() ?: [];

    return [
        'total_count' => (int) ($row['total_count'] ?? 0),
        'public_count' => (int) ($row['public_count'] ?? 0),
        'private_count' => (int) ($row['private_count'] ?? 0),
        'summarized_count' => (int) ($row['summarized_count'] ?? 0),
    ];
}

function library_handle_uploaded_file(array $file): array
{
    if (($file['error'] ?? UPLOAD_ERR_NO_FILE) !== UPLOAD_ERR_OK) {
        throw new RuntimeException('Please upload a document file.');
    }

    $originalName = (string) ($file['name'] ?? '');
    $extension = strtolower(pathinfo($originalName, PATHINFO_EXTENSION));
    $allowed = library_allowed_extensions();
    if (!isset($allowed[$extension])) {
        throw new RuntimeException('Unsupported file type.');
    }

    $size = (int) ($file['size'] ?? 0);
    if ($size <= 0 || $size > 12 * 1024 * 1024) {
        throw new RuntimeException('File must be smaller than 12 MB.');
    }

    $safeBase = preg_replace('/[^a-zA-Z0-9_-]+/', '-', pathinfo($originalName, PATHINFO_FILENAME)) ?: 'document';
    $storedName = strtolower(date('YmdHis') . '-' . $safeBase . '-' . bin2hex(random_bytes(4)) . '.' . $extension);
    $relativePath = 'uploads/library/' . $storedName;
    $absolutePath = __DIR__ . '/../' . $relativePath;

    if (!move_uploaded_file((string) $file['tmp_name'], $absolutePath)) {
        throw new RuntimeException('Unable to save the uploaded file.');
    }

    return [
        'file_name' => $originalName,
        'file_path' => $relativePath,
        'document_type' => $extension,
        'file_size_kb' => (int) ceil($size / 1024),
    ];
}

function library_create_document(array $payload, array $file): int
{
    library_bootstrap();

    $titleEn = trim((string) ($payload['title_en'] ?? ''));
    $titleAr = trim((string) ($payload['title_ar'] ?? ''));
    
    // Process IDs
    $categoryId = !empty($payload['category_id']) ? (int)$payload['category_id'] : null;
    $subcategoryId = !empty($payload['subcategory_id']) ? (int)$payload['subcategory_id'] : null;
    
    // Fetch names for backward compatibility if needed, or just store IDs
    $categoryName = '';
    $categoryNameAr = '';
    $subName = '';
    $subNameAr = '';

    if ($categoryId) {
        $cat = library_get_category_by_id($categoryId);
        if ($cat) {
            $categoryName = $cat['name_en'];
            $categoryNameAr = $cat['name_ar'];
        }
    }
    if ($subcategoryId) {
        $sub = library_get_subcategory_by_id($subcategoryId);
        if ($sub) {
            $subName = $sub['name_en'];
            $subNameAr = $sub['name_ar'];
        }
    }

    $visibility = (string) ($payload['visibility'] ?? 'public');
    $allow_download = !empty($payload['allow_download']) ? 1 : 0;
    $allow_print = !empty($payload['allow_print']) ? 1 : 0;
    $allow_copy = !empty($payload['allow_copy']) ? 1 : 0;

    $fileData = library_handle_uploaded_file($file);

    $stmt = db()->prepare('INSERT INTO library_documents (
        title_en, title_ar, 
        category, category_ar, sub_category, sub_category_ar, 
        category_id, subcategory_id,
        visibility, document_type,
        file_name, file_path, file_size_kb, allow_download, allow_print, allow_copy
    ) VALUES (
        :title_en, :title_ar, 
        :category, :category_ar, :sub_category, :sub_category_ar, 
        :category_id, :subcategory_id,
        :visibility, :document_type,
        :file_name, :file_path, :file_size_kb, :allow_download, :allow_print, :allow_copy
    )');

    $stmt->execute([
        ':title_en' => $titleEn ?: null,
        ':title_ar' => $titleAr ?: null,
        ':category' => $categoryName ?: null,
        ':category_ar' => $categoryNameAr ?: null,
        ':sub_category' => $subName ?: null,
        ':sub_category_ar' => $subNameAr ?: null,
        ':category_id' => $categoryId,
        ':subcategory_id' => $subcategoryId,
        ':visibility' => $visibility,
        ':document_type' => $fileData['document_type'],
        ':file_name' => $fileData['file_name'],
        ':file_path' => $fileData['file_path'],
        ':file_size_kb' => $fileData['file_size_kb'],
        ':allow_download' => $allow_download,
        ':allow_print' => $allow_print,
        ':allow_copy' => $allow_copy,
    ]);

    return (int) db()->lastInsertId();
}