<?php
namespace OCA\GroupfolderFilesystemSnapshots\Service;

use Exception;

use OCP\AppFramework\Db\DoesNotExistException;
use OCP\AppFramework\Db\MultipleObjectsReturnedException;

use OCA\GroupfolderFilesystemSnapshots\Exceptions\NotFoundException;
use OCA\GroupfolderFilesystemSnapshots\Db\DiffTask;
use OCA\GroupfolderFilesystemSnapshots\Db\DiffTaskMapper;
use OCA\GroupfolderFilesystemSnapshots\Db\DiffTaskResult;
use OCA\GroupfolderFilesystemSnapshots\Db\DiffTaskResultMapper;
use OCA\GroupfolderFilesystemSnapshots\Manager\PathManager;
use OCA\GroupfolderFilesystemSnapshots\RecursiveDiff;


class DiffTaskService {

    private DiffTaskMapper $mapper;
    private DiffTaskResultMapper $diffTaskResultMapper;
    private PathManager $pathManager;

    public function __construct(DiffTaskMapper $mapper, DiffTaskResultMapper $diffTaskResultMapper, PathManager $pathManager){
        $this->mapper = $mapper;
        $this->diffTaskResultMapper = $diffTaskResultMapper;
        $this->pathManager = $pathManager;
    }

    /**
     * @return DiffTask[]
     */
    public function findAll(string $userId): array {
        return $this->mapper->findAll($userId);
    }

    /**
     * @return never
     */
    private function handleException ($e, $criteria) {
        if ($e instanceof DoesNotExistException ||
            $e instanceof MultipleObjectsReturnedException) {
            throw new NotFoundException($e->getMessage(), $criteria);
        } else {
            throw $e;
        }
    }

    public function find(int $id, string $userId): DiffTask {
        try {
            return $this->mapper->find($id, $userId);
        } catch(Exception $e) {
            $this->handleException($e, ["userId" => $userId, "id" => $id]);
        }
    }

    function create(int $groupfolderId, string $snapshotId, string $userId, Callable $progressCallback = null): DiffTask {
        $snapshotPath = $this->pathManager->getGroupFolderSnapshotDirectory($groupfolderId, $snapshotId);
        $groupfolderPath = $this->pathManager->getGroupFolderDirectory($groupfolderId);

        $newTask = new DiffTask();
        $newTask->setGroupfolderId($groupfolderId);
        $newTask->setSnapshotId($snapshotId);
        $newTask->setTimestamp(time());
        $newTask->setUserId($userId);
        $task = $this->mapper->insert($newTask);

        $numFiles = 0;

        $diffTask = new RecursiveDiff(
            $snapshotPath,
            $groupfolderPath,
            "",
            function(string $type, bool $beforeFileExists, ?string $beforePath, ?int $beforeSize, bool $currentFileExists, ?string $currentPath, ?int $currentSize) use ($task) {
                $newResult = new DiffTaskResult();
                $newResult->setTaskId($task->getId());
                $newResult->setType($type);
                $newResult->setBeforeFileExists($beforeFileExists);
                $newResult->setBeforePath($beforePath);
                $newResult->setBeforeSize($beforeSize);
                $newResult->setCurrentFileExists($currentFileExists);
                $newResult->setCurrentPath($currentPath);
                $newResult->setCurrentSize($currentSize);
                $newResult = $this->diffTaskResultMapper->insert($newResult);
            },
            function($numDoneFiles) use ($progressCallback, &$numFiles) {
                if(isset($progressCallback) && ($numFiles != 0) && ($numFiles != $numDoneFiles)) {
                    ($progressCallback)([
                        "overallFiles" => $numFiles,
                        "doneFiles" => $numDoneFiles,
                        "progress" => number_format(($numDoneFiles / $numFiles),2),
                        "progressPercent" => (number_format(($numDoneFiles / $numFiles),2) * 100) . "%",
                    ]);
                }
            },
        );

        $numFiles = $diffTask->scan();

        $diffTask->diff();

        if(isset($progressCallback)) {
            ($progressCallback)([
                "overallFiles" => $numFiles,
                "doneFiles" => $numFiles,
                "progress" => 1.0,
                "progressPercent" => "100.00%",
                "result" => $task,
            ]);
        }

        return $task;
    }

    public function delete(int $id, string $userId): DiffTask {
        try {
            $task = $this->mapper->find($id, $userId);
            $this->mapper->delete($task);
            return $task;
        } catch(Exception $e) {
            $this->handleException($e);
        }
    }

}