<?php
declare(strict_types=1);

namespace App\Service\Storage;

use ApiPlatform\Core\Api\IriConverterInterface;
use App\ApiResources\DownloadRequest;
use App\Entity\Access\Access;
use App\Entity\Core\File;
use App\Entity\Organization\Organization;
use App\Entity\Person\Person;
use App\Enum\Core\FileStatusEnum;
use App\Enum\Core\FileTypeEnum;
use App\Repository\Access\AccessRepository;
use App\Service\Utils\Path;
use App\Service\Utils\Uuid;
use DateTime;
use Doctrine\ORM\EntityManagerInterface;
use Gaufrette\Filesystem;
use JetBrains\PhpStorm\Pure;
use Knp\Bundle\GaufretteBundle\FilesystemMap;
use Mimey\MimeTypes;
use RuntimeException;

/**
 * Read and write files into the file storage
 */
class LocalStorage implements FileStorageInterface
{
    /**
     * Key of the gaufrette storage, as defined in config/packages/knp_gaufrette.yaml
     */
    protected const FS_KEY = 'storage';

    protected Filesystem $filesystem;

    public function __construct(
        protected FilesystemMap $filesystemMap,
        protected EntityManagerInterface $entityManager,
        protected AccessRepository $accessRepository,
        protected IriConverterInterface $iriConverter
    )
    {
        $this->filesystem = $filesystemMap->get(static::FS_KEY);
    }

    /**
     * Return true if the file exists in the file storage
     *
     * @param File $file
     * @return bool
     */
    public function exists(File $file): bool {
        return $this->filesystem->has($file->getSlug());
    }

    /**
     * Get the IRI to download this file (eg: /api/download/1)
     *
     * @param File $file
     * @return string
     */
    public function getDownloadIri(File $file): string
    {
        return $this->iriConverter->getItemIriFromResourceClass(
            DownloadRequest::class,
            ['fileId' => $file->getId()]
        );
    }

    /**
     * Lists all the non-temporary files of the given owner
     *
     * @param Organization|Access|Person $owner
     * @param FileTypeEnum|null $type
     * @return array
     */
    public function listByOwner (
        Organization | Access | Person $owner,
        ?FileTypeEnum $type = null
    ): array {
        return $this->filesystem->listKeys(
            $this->getPrefix($owner, false, $type?->getValue())
        );
    }

    /**
     * Reads the given file and returns its content as a string
     *
     * @param File $file
     * @return string
     */
    public function read(File $file): string
    {
        return $this->filesystem->read($file->getSlug());
    }

    /**
     * Prepare a File record with a PENDING status.
     * This record will hold all the data needed to create the file, except its content.
     *
     * @param Organization|Access|Person $owner Owner of the file, either an organization, a person or both (access)
     * @param string $filename The file's name (mandatory)
     * @param FileTypeEnum $type The type of the new file
     * @param Access $createdBy Id of the access responsible for this creation
     * @param bool $isTemporary Is it a temporary file that can be deleted after some time
     * @param string|null $mimeType Mimetype of the file, if not provided, the method will try to guess it from its file name's extension
     * @param string $visibility
     * @param bool $flushFile Should the newly created file be flushed after having been persisted?
     * @return File
     */
    public function prepareFile(
        Organization | Access | Person $owner,
        string $filename,
        FileTypeEnum $type,
        Access $createdBy,
        bool $isTemporary = false,
        string $visibility = 'NOBODY',
        string $mimeType = null,
        bool $flushFile = true
    ): File
    {
        [$organization, $person] = $this->getOrganizationAndPersonFromOwner($owner);

        $file = (new File())
            ->setName($filename)
            ->setOrganization($organization)
            ->setPerson($person)
            ->setSlug(null)
            ->setType($type->getValue())
            ->setVisibility($visibility)
            ->setIsTemporaryFile($isTemporary)
            ->setMimeType($mimeType ?? self::guessMimeTypeFromFilename($filename))
            ->setCreateDate(new DateTime())
            ->setCreatedBy($createdBy->getId())
            ->setStatus(FileStatusEnum::PENDING()->getValue());

        $this->entityManager->persist($file);

        if ($flushFile) {
            $this->entityManager->flush();
        }

        return $file;
    }

    /**
     * Write the $content into the file storage and update the given File object's size, slug, status (READY)...
     *
     * @param File $file The file object that is about to be written
     * @param string $content The content of the file
     * @param Access $author The access responsible for the creation / update of the file
     * @return File
     */
    public function writeFile(File $file, string $content, Access $author): File
    {
        if (empty($file->getName())) {
            throw new RuntimeException('File has no filename');
        }

        $isNewFile = $file->getSlug() === null;
        if ($isNewFile) {
            // Try to get the Access owner from the organization_id and person_id
            $access = null;
            if ($file->getOrganization() !== null && $file->getPerson() !== null) {
                $access = $this->accessRepository->findOneBy(
                    ['organization' => $file->getOrganization(), 'person' => $file->getPerson()]
                );
            }

            $prefix = $this->getPrefix(
                $access ?? $file->getOrganization() ?? $file->getPerson(),
                $file->getIsTemporaryFile(),
                $file->getType()
            );

            $uid = date('Ymd_His') . '_' . Uuid::uuid(5);

            $key = Path::join($prefix, $uid, $file->getName());
        } else {
            $key = $file->getSlug();
        }

        if (!$isNewFile && !$this->filesystem->has($key)) {
            throw new RuntimeException('The file `' . $key . '` does not exist in the file storage');
        }

        $size = $this->filesystem->write($key, $content, true);

        $file->setSize($size)
             ->setStatus(FileStatusEnum::READY()->getValue());

        if ($isNewFile) {
            $file->setSlug($key)
                 ->setCreateDate(new DateTime())
                 ->setCreatedBy($author->getId());
        } else {
            $file->setUpdateDate(new DateTime())
                 ->setUpdatedBy($author->getId());
        }

        $this->entityManager->flush();

        return $file;
    }

    /**
     * Convenient method to successively prepare and write a file
     *
     * @param Organization|Access|Person $owner
     * @param string $filename
     * @param FileTypeEnum $type
     * @param string $content
     * @param Access $author
     * @param bool $isTemporary
     * @param string|null $mimeType
     * @param string $visibility
     * @return File
     */
    public function makeFile (
        Organization | Access | Person $owner,
        string                         $filename,
        FileTypeEnum                   $type,
        string                         $content,
        Access                         $author,
        bool                           $isTemporary = false,
        string                         $visibility = 'NOBODY',
        string                         $mimeType = null
    ): File
    {
        $file = $this->prepareFile(
            $owner,
            $filename,
            $type,
            $author,
            $isTemporary,
            $visibility,
            $mimeType,
            false
        );

        return $this->writeFile($file, $content, $author);
    }

    /**
     * Delete the given file from the filesystem and update the status of the File
     *
     * @param File $file
     * @param Access $author
     * @return File
     */
    public function delete(File $file, Access $author): File
    {
        $deleted = $this->filesystem->delete($file->getSlug());

        if (!$deleted) {
            throw new RuntimeException('File `' . $file->getSlug() . '` could\'nt be deleted');
        }

        $file->setStatus(FileStatusEnum::DELETED()->getValue())
             ->setSize(0)
             ->setUpdatedBy($author->getId());

        $this->entityManager->flush();

        return $file;
    }

    /**
     * Return the mimetype corresponding to the givent file extension
     *
     * @param string $ext
     * @return string|null
     */
    public static function getMimeTypeFromExt(string $ext): string | null {
        return (new MimeTypes)->getMimeType(ltrim($ext, '.'));
    }

    /**
     * Try to guess the mimetype from the filename
     *
     * Return null if it did not manage to guess it.
     *
     * @param string $filename
     * @return string|null
     */
    public static function guessMimeTypeFromFilename(string $filename): string | null {
        $ext = pathinfo($filename, PATHINFO_EXTENSION);
        if (empty($ext)) {
            return null;
        }
        return self::getMimeTypeFromExt($ext);
    }

    /**
     * If an organization owns the file, the prefix will be '(_temp_/)organization/{id}(/{type})'.
     * If a person owns it, the prefix will be '(_temp_/)person/{id}(/{type})'
     * If access owns it, the prefix will be '(_temp_/)organization/{organization_id}/{access_id}(/{type})'
     *
     * With {id} being the id of the organization or of the person.
     *
     * If the file is temporary, '_temp_/' is prepended to the prefix.
     * If a file type is given, this type is appended to the prefix (low case)
     *
     * @param Organization|Access|Person $owner
     * @param bool $isTemporary
     * @param string|null $type
     * @return string
     */
    protected function getPrefix(
        Organization | Access | Person $owner,
        bool $isTemporary,
        string $type = null
    ): string
    {
        if ($owner instanceof Access) {
            $prefix = Path::join('organization', $owner->getOrganization()?->getId(), $owner->getId());
        } else if ($owner instanceof Organization) {
            $prefix = Path::join('organization', $owner->getId());
        } else {
            $prefix = Path::join('person', $owner->getId());
        }

        if ($isTemporary) {
            $prefix = Path::join('temp', $prefix);
        }

        if ($type !== null && $type !== FileTypeEnum::NONE()->getValue()) {
            $prefix = Path::join($prefix, strtolower($type));
        }

        return $prefix;
    }

    /**
     * Return an array [$organization, $person] from a given owner
     *
     * @param Organization|Access|Person $owner
     * @return array
     */
    #[Pure]
    protected function getOrganizationAndPersonFromOwner(Organization | Access | Person $owner): array {
        if ($owner instanceof Access) {
            return [$owner->getOrganization(), $owner->getPerson()];
        }

        if ($owner instanceof Organization) {
            return [$owner, null];
        }

        return [null, $owner];
    }
}