<?php
/**
 * Database connection (PDO singleton) and CRUD helpers.
 * All queries use prepared statements.
 */

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

function db(): PDO
{
    static $pdo = null;
    if ($pdo === null) {
        $dsn = 'mysql:host=' . DB_HOST . ';dbname=' . DB_NAME . ';charset=' . DB_CHARSET;
        $pdo = new PDO($dsn, DB_USER, DB_PASS, [
            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES   => false,
        ]);
    }
    return $pdo;
}

// ---- Repositories -----------------------------------------------------------

/**
 * Sort options for the repository list, keyed by the value used in the URL.
 * Each value is a fixed ORDER BY clause (never interpolate user input directly).
 */
const REPO_SORTS = [
    'newest' => 'created_at DESC, id DESC',
    'oldest' => 'created_at ASC, id ASC',
    'name'   => 'name ASC, id ASC',
    'slug'   => 'slug ASC',
];

function get_repositories(string $sort = 'newest'): array
{
    $order = REPO_SORTS[$sort] ?? REPO_SORTS['newest'];
    $stmt = db()->query('SELECT * FROM repositories ORDER BY ' . $order);
    return $stmt->fetchAll();
}

function get_repository_by_slug(string $slug): ?array
{
    $stmt = db()->prepare('SELECT * FROM repositories WHERE slug = ? LIMIT 1');
    $stmt->execute([$slug]);
    $row = $stmt->fetch();
    return $row ?: null;
}

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

function create_repository(string $slug, string $name, string $desc, string $lang): int
{
    $stmt = db()->prepare(
        'INSERT INTO repositories (slug, name, description, language) VALUES (?, ?, ?, ?)'
    );
    $stmt->execute([$slug, $name, $desc, $lang]);
    return (int) db()->lastInsertId();
}

function update_repository(int $id, string $name, string $desc, string $lang): void
{
    $stmt = db()->prepare(
        'UPDATE repositories SET name = ?, description = ?, language = ? WHERE id = ?'
    );
    $stmt->execute([$name, $desc, $lang, $id]);
}

/**
 * Rename a repository's slug. Updates the repositories row and rewrites the
 * stored slug prefix on every file's `filepath` (which is "slug/rel-path").
 * Runs in a transaction so both tables stay consistent. The caller is
 * responsible for renaming the on-disk uploads/<slug> directory.
 */
function rename_repository(int $id, string $oldSlug, string $newSlug): void
{
    $pdo = db();
    $pdo->beginTransaction();
    try {
        $stmt = $pdo->prepare('UPDATE repositories SET slug = ? WHERE id = ?');
        $stmt->execute([$newSlug, $id]);

        // filepath looks like "oldslug/dir/file.ext" — swap the leading segment.
        $stmt = $pdo->prepare(
            'UPDATE files SET filepath = CONCAT(?, SUBSTRING(filepath, ?)) WHERE repo_id = ?'
        );
        $stmt->execute([$newSlug, strlen($oldSlug) + 1, $id]);

        $pdo->commit();
    } catch (Throwable $e) {
        $pdo->rollBack();
        throw $e;
    }
}

function delete_repository(int $id): void
{
    // Files rows are removed automatically via ON DELETE CASCADE.
    $stmt = db()->prepare('DELETE FROM repositories WHERE id = ?');
    $stmt->execute([$id]);
}

// ---- Files ------------------------------------------------------------------

function get_files_by_repo(int $repoId): array
{
    $stmt = db()->prepare('SELECT * FROM files WHERE repo_id = ? ORDER BY filename ASC');
    $stmt->execute([$repoId]);
    return $stmt->fetchAll();
}

function get_file_by_name(int $repoId, string $filename): ?array
{
    $stmt = db()->prepare('SELECT * FROM files WHERE repo_id = ? AND filename = ? LIMIT 1');
    $stmt->execute([$repoId, $filename]);
    $row = $stmt->fetch();
    return $row ?: null;
}

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

function create_file(int $repoId, string $filename, string $filepath, int $size): int
{
    // Replace an existing same-named file record for this repo (re-upload).
    $stmt = db()->prepare(
        'INSERT INTO files (repo_id, filename, filepath, filesize)
         VALUES (?, ?, ?, ?)
         ON DUPLICATE KEY UPDATE filepath = VALUES(filepath), filesize = VALUES(filesize)'
    );
    $stmt->execute([$repoId, $filename, $filepath, $size]);
    return (int) db()->lastInsertId();
}

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

// ---- Folders ----------------------------------------------------------------

function get_folders_by_repo(int $repoId): array
{
    $stmt = db()->prepare('SELECT * FROM folders WHERE repo_id = ? ORDER BY path ASC');
    $stmt->execute([$repoId]);
    return $stmt->fetchAll();
}

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

/**
 * Register a folder path and all of its ancestors. For "a/b/c" this inserts
 * "a", "a/b" and "a/b/c". Existing rows are ignored (INSERT IGNORE).
 */
function create_folder(int $repoId, string $path): void
{
    $stmt  = db()->prepare('INSERT IGNORE INTO folders (repo_id, path) VALUES (?, ?)');
    $accum = [];
    foreach (explode('/', trim($path, '/')) as $seg) {
        if ($seg === '') {
            continue;
        }
        $accum[] = $seg;
        $stmt->execute([$repoId, implode('/', $accum)]);
    }
}

/**
 * Delete a folder plus every sub-folder and file beneath it. Returns the
 * deleted folder's path (so the caller can remove it from disk), or null.
 */
function delete_folder(int $id): ?string
{
    $folder = get_folder($id);
    if (!$folder) {
        return null;
    }
    $repoId = (int) $folder['repo_id'];
    $path   = $folder['path'];

    // Escape LIKE wildcards in the stored path (safe_relpath permits "_").
    $prefix = str_replace(['\\', '%', '_'], ['\\\\', '\\%', '\\_'], $path) . '/%';

    // Files that live inside the folder.
    $stmt = db()->prepare('DELETE FROM files WHERE repo_id = ? AND filename LIKE ?');
    $stmt->execute([$repoId, $prefix]);

    // The folder row itself and all descendant folder rows.
    $stmt = db()->prepare('DELETE FROM folders WHERE repo_id = ? AND (path = ? OR path LIKE ?)');
    $stmt->execute([$repoId, $path, $prefix]);

    return $path;
}