<?php

declare(strict_types=1);
/**
 * SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

namespace OC\Core\Command\Info;

use OC\User\NoUserException;
use OCA\Circles\MountManager\CircleMount;
use OCA\Files_External\Config\ExternalMountPoint;
use OCA\Files_Sharing\SharedMount;
use OCA\GroupFolders\Mount\GroupMountPoint;
use OCP\Constants;
use OCP\DB\QueryBuilder\IQueryBuilder;
use OCP\Files\Config\IUserMountCache;
use OCP\Files\FileInfo;
use OCP\Files\Folder;
use OCP\Files\IHomeStorage;
use OCP\Files\IRootFolder;
use OCP\Files\Mount\IMountPoint;
use OCP\Files\Node;
use OCP\Files\NotFoundException;
use OCP\Files\NotPermittedException;
use OCP\IDBConnection;
use OCP\Share\IShare;
use OCP\Util;
use Symfony\Component\Console\Output\OutputInterface;

/**
 * @psalm-type StorageInfo array{numeric_id: int, id: string, available: bool, last_checked: ?\DateTime, files: int, mount_id: ?int}
 */
class FileUtils {
	public function __construct(
		private IRootFolder $rootFolder,
		private IUserMountCache $userMountCache,
		private IDBConnection $connection,
	) {
	}

	/**
	 * @param FileInfo $file
	 * @return array<string, Node[]>
	 * @throws NotPermittedException
	 * @throws NoUserException
	 */
	public function getFilesByUser(FileInfo $file): array {
		$id = $file->getId();
		if (!$id) {
			return [];
		}

		$mounts = $this->userMountCache->getMountsForFileId($id);
		$result = [];
		foreach ($mounts as $cachedMount) {
			$mount = $this->rootFolder->getMount($cachedMount->getMountPoint());
			$cache = $mount->getStorage()->getCache();
			$cacheEntry = $cache->get($id);
			$node = $this->rootFolder->getNodeFromCacheEntryAndMount($cacheEntry, $mount);
			$result[$cachedMount->getUser()->getUID()][] = $node;
		}

		return $result;
	}

	/**
	 * Get file by either id of path
	 *
	 * @param string $fileInput
	 * @return Node|null
	 */
	public function getNode(string $fileInput): ?Node {
		if (is_numeric($fileInput)) {
			$mounts = $this->userMountCache->getMountsForFileId((int)$fileInput);
			if (!$mounts) {
				return null;
			}
			$mount = reset($mounts);
			$userFolder = $this->rootFolder->getUserFolder($mount->getUser()->getUID());
			return $userFolder->getFirstNodeById((int)$fileInput);
		} else {
			try {
				return $this->rootFolder->get($fileInput);
			} catch (NotFoundException $e) {
				return null;
			}
		}
	}

	public function formatPermissions(string $type, int $permissions): string {
		if ($permissions == Constants::PERMISSION_ALL || ($type === 'file' && $permissions == (Constants::PERMISSION_ALL - Constants::PERMISSION_CREATE))) {
			return 'full permissions';
		}

		$perms = [];
		$allPerms = [Constants::PERMISSION_READ => 'read', Constants::PERMISSION_UPDATE => 'update', Constants::PERMISSION_CREATE => 'create', Constants::PERMISSION_DELETE => 'delete', Constants::PERMISSION_SHARE => 'share'];
		foreach ($allPerms as $perm => $name) {
			if (($permissions & $perm) === $perm) {
				$perms[] = $name;
			}
		}

		return implode(', ', $perms);
	}

	/**
	 * @psalm-suppress UndefinedClass
	 * @psalm-suppress UndefinedInterfaceMethod
	 */
	public function formatMountType(IMountPoint $mountPoint): string {
		$storage = $mountPoint->getStorage();
		if ($storage && $storage->instanceOfStorage(IHomeStorage::class)) {
			return 'home storage';
		} elseif ($mountPoint instanceof SharedMount) {
			$share = $mountPoint->getShare();
			$shares = $mountPoint->getGroupedShares();
			$sharedBy = array_map(function (IShare $share) {
				$shareType = $this->formatShareType($share);
				if ($shareType) {
					return $share->getSharedBy() . ' (via ' . $shareType . ' ' . $share->getSharedWith() . ')';
				} else {
					return $share->getSharedBy();
				}
			}, $shares);
			$description = 'shared by ' . implode(', ', $sharedBy);
			if ($share->getSharedBy() !== $share->getShareOwner()) {
				$description .= ' owned by ' . $share->getShareOwner();
			}
			return $description;
		} elseif ($mountPoint instanceof GroupMountPoint) {
			return 'groupfolder ' . $mountPoint->getFolderId();
		} elseif ($mountPoint instanceof ExternalMountPoint) {
			return 'external storage ' . $mountPoint->getStorageConfig()->getId();
		} elseif ($mountPoint instanceof CircleMount) {
			return 'circle';
		}
		return get_class($mountPoint);
	}

	public function formatShareType(IShare $share): ?string {
		switch ($share->getShareType()) {
			case IShare::TYPE_GROUP:
				return 'group';
			case IShare::TYPE_CIRCLE:
				return 'circle';
			case IShare::TYPE_DECK:
				return 'deck';
			case IShare::TYPE_ROOM:
				return 'room';
			case IShare::TYPE_USER:
				return null;
			default:
				return 'Unknown (' . $share->getShareType() . ')';
		}
	}

	/**
	 * Print out the largest count($sizeLimits) files in the directory tree
	 *
	 * @param OutputInterface $output
	 * @param Folder $node
	 * @param string $prefix
	 * @param array $sizeLimits largest items that are still in the queue to be printed, ordered ascending
	 * @return int how many items we've printed
	 */
	public function outputLargeFilesTree(
		OutputInterface $output,
		Folder $node,
		string $prefix,
		array &$sizeLimits,
		bool $all,
	): int {
		/**
		 * Algorithm to print the N largest items in a folder without requiring to query or sort the entire three
		 *
		 * This is done by keeping a list ($sizeLimits) of size N that contain the largest items outside of this
		 * folders that are could be printed if there aren't enough items in this folder that are larger.
		 *
		 * We loop over the items in this folder by size descending until the size of the item falls before the smallest
		 * size in $sizeLimits (at that point there are enough items outside this folder to complete the N items).
		 *
		 * When encountering a folder, we create an updated $sizeLimits with the largest items in the current folder still
		 * remaining which we pass into the recursion. (We don't update the current $sizeLimits because that should only
		 * hold items *outside* of the current folder.)
		 *
		 * For every item printed we remove the first item of $sizeLimits are there is no longer room in the output to print
		 * items that small.
		 */

		$count = 0;
		$children = $node->getDirectoryListing();
		usort($children, function (Node $a, Node $b) {
			return $b->getSize() <=> $a->getSize();
		});
		foreach ($children as $i => $child) {
			if (!$all) {
				if (count($sizeLimits) === 0 || $child->getSize() < $sizeLimits[0]) {
					return $count;
				}
				array_shift($sizeLimits);
			}
			$count += 1;

			/** @var Node $child */
			$output->writeln("$prefix- " . $child->getName() . ': <info>' . Util::humanFileSize($child->getSize()) . '</info>');
			if ($child instanceof Folder) {
				$recurseSizeLimits = $sizeLimits;
				if (!$all) {
					for ($j = 0; $j < count($recurseSizeLimits); $j++) {
						if (isset($children[$i + $j + 1])) {
							$nextChildSize = $children[$i + $j + 1]->getSize();
							if ($nextChildSize > $recurseSizeLimits[0]) {
								array_shift($recurseSizeLimits);
								$recurseSizeLimits[] = $nextChildSize;
							}
						}
					}
					sort($recurseSizeLimits);
				}
				$recurseCount = $this->outputLargeFilesTree($output, $child, $prefix . '  ', $recurseSizeLimits, $all);
				$sizeLimits = array_slice($sizeLimits, $recurseCount);
				$count += $recurseCount;
			}
		}
		return $count;
	}

	public function getNumericStorageId(string $id): ?int {
		if (is_numeric($id)) {
			return (int)$id;
		}
		$query = $this->connection->getQueryBuilder();
		$query->select('numeric_id')
			->from('storages')
			->where($query->expr()->eq('id', $query->createNamedParameter($id)));
		$result = $query->executeQuery()->fetchOne();
		return $result ? (int)$result : null;
	}

	/**
	 * @param int|null $limit
	 * @return ?StorageInfo
	 * @throws \OCP\DB\Exception
	 */
	public function getStorage(int $id): ?array {
		$query = $this->connection->getQueryBuilder();
		$query->select('numeric_id', 's.id', 'available', 'last_checked', 'mount_id')
			->selectAlias($query->func()->count('fileid'), 'files')
			->from('storages', 's')
			->innerJoin('s', 'filecache', 'f', $query->expr()->eq('f.storage', 's.numeric_id'))
			->leftJoin('s', 'mounts', 'm', $query->expr()->eq('s.numeric_id', 'm.storage_id'))
			->where($query->expr()->eq('s.numeric_id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT)))
			->groupBy('s.numeric_id', 's.id', 's.available', 's.last_checked', 'mount_id');
		$row = $query->executeQuery()->fetch();
		if ($row) {
			return [
				'numeric_id' => $row['numeric_id'],
				'id' => $row['id'],
				'files' => $row['files'],
				'available' => (bool)$row['available'],
				'last_checked' => $row['last_checked'] ? new \DateTime('@' . $row['last_checked']) : null,
				'mount_id' => $row['mount_id'],
			];
		} else {
			return null;
		}
	}

	/**
	 * @param int|null $limit
	 * @return \Iterator<StorageInfo>
	 * @throws \OCP\DB\Exception
	 */
	public function listStorages(?int $limit): \Iterator {
		$query = $this->connection->getQueryBuilder();
		$query->select('numeric_id', 's.id', 'available', 'last_checked', 'mount_id')
			->selectAlias($query->func()->count('fileid'), 'files')
			->from('storages', 's')
			->innerJoin('s', 'filecache', 'f', $query->expr()->eq('f.storage', 's.numeric_id'))
			->leftJoin('s', 'mounts', 'm', $query->expr()->eq('s.numeric_id', 'm.storage_id'))
			->groupBy('s.numeric_id', 's.id', 's.available', 's.last_checked', 'mount_id')
			->orderBy('files', 'DESC');
		if ($limit !== null) {
			$query->setMaxResults($limit);
		}
		$result = $query->executeQuery();
		while ($row = $result->fetch()) {
			yield [
				'numeric_id' => $row['numeric_id'],
				'id' => $row['id'],
				'files' => $row['files'],
				'available' => (bool)$row['available'],
				'last_checked' => $row['last_checked'] ? new \DateTime('@' . $row['last_checked']) : null,
				'mount_id' => $row['mount_id'],
			];
		}
	}

	/**
	 * @param StorageInfo $storage
	 * @return array
	 */
	public function formatStorage(array $storage): array {
		return [
			'numeric_id' => $storage['numeric_id'],
			'id' => $storage['id'],
			'files' => $storage['files'],
			'available' => $storage['available'] ? 'true' : 'false',
			'last_checked' => $storage['last_checked']?->format(\DATE_ATOM),
			'external_mount_id' => $storage['mount_id'],
		];
	}

	/**
	 * @param \Iterator<StorageInfo> $storages
	 * @return \Iterator
	 */
	public function formatStorages(\Iterator $storages): \Iterator {
		foreach ($storages as $storage) {
			yield $this->formatStorage($storage);
		}
	}
}