<?php
namespace ProVM\Service;

use ProVM\Exception\Response\EmptyResponse;
use ProVM\Exception\Response\MissingResponse;
use Psr\Log\LoggerInterface;
use function Safe\json_decode;

class Attachments
{
    public function __construct(protected Communicator $communicator, protected LoggerInterface $logger, protected array $passwords, protected string $base_command = 'qpdf') {}

    protected array $attachments;

    public function findAll(): \Generator
    {
        $this->logger->info('Finding all downloaded attachment files');
        $folder = '/attachments';
        $files = new \FilesystemIterator($folder);
        foreach ($files as $file) {
            if ($file->isDir()) {
                continue;
            }
            yield $file->getRealPath();
        }
    }
    public function getAll(): array
    {
        if (!isset($this->attachments)) {
            $this->logger->info('Grabbing all attachments');
            $response = $this->communicator->get('/attachments');
            $body = $response->getBody()->getContents();
            if (trim($body) === '') {
                $this->attachments = [];
                return $this->attachments;
            }
            $this->attachments = json_decode($body)->attachments;
        }
        return $this->attachments;
    }
    public function get(int $attachment_id): object
    {
        $this->logger->info("Getting attachment {$attachment_id}");
        $uri = "/attachment/{$attachment_id}";
        $response = $this->communicator->get($uri);
        $body = $response->getBody()->getContents();
        if (trim($body) === '') {
            throw new EmptyResponse($uri);
        }
        $json = json_decode($body);
        if (!isset($json->attachment)) {
            throw new MissingResponse('attachment');
        }
        return $json->attachment;
    }
    public function find(string $filename): int
    {
        $this->logger->info("Finding attachment {$filename}");
        foreach ($this->getAll() as $attachment) {
            if ($attachment->fullfilename === $filename) {
                return $attachment->id;
            }
        }
        throw new \Exception("{$filename} is not in the database");
    }
    public function isEncrypted(string $filename): bool
    {
        if (!file_exists($filename)) {
            throw new \InvalidArgumentException("File not found {$filename}");
        }
        $escaped_filename = escapeshellarg($filename);
        $cmd = "{$this->base_command} --is-encrypted {$escaped_filename}";
        exec($cmd, $output, $retcode);
        return $retcode == 0;
    }
    public function scheduleDecrypt(int $attachment_id): bool
    {
        $this->logger->info("Scheduling decryption of attachment {$attachment_id}");
        $uri = "/attachment/{$attachment_id}/decrypt";
        $response = $this->communicator->get($uri);
        $body = $response->getBody()->getContents();
        if (trim($body) === '') {
            throw new EmptyResponse($uri);
        }
        $json = json_decode($body);
        if (!isset($json->status)) {
            throw new MissingResponse('status');
        }
        return $json->status;
    }
    public function decrypt(string $basename): bool
    {
        $this->logger->info("Decrypting {$basename}");
        $in_filename = implode('/', ['attachments', $basename]);
        $out_filename = implode('/', ['attachments', 'decrypted', $basename]);
        if (file_exists($out_filename)) {
            throw new \Exception("{$basename} already decrypted");
        }
        foreach ($this->passwords as $password) {
            $cmd = $this->base_command . ' -password=' . escapeshellarg($password) . ' -decrypt ' . escapeshellarg($in_filename) . ' ' . escapeshellarg($out_filename);
            exec($cmd, $output, $retcode);
            $success = $retcode == 0;
            if ($success) {
                return true;
            }
            if (file_exists($out_filename)) {
                unlink($out_filename);
            }
            unset($output);
        }
        return false;
    }

}