<?php

namespace App\Livewire;

use App\Models\Setting;
use App\Models\Share;
use App\Services\PasswordGeneratorService;
use App\Services\ShareService;
use Illuminate\Support\Facades\Crypt;
use Illuminate\Support\Str;
use Illuminate\Validation\ValidationException;
use Livewire\Attributes\Layout;
use Livewire\Attributes\Locked;
use Livewire\Component;

/**
 * The upload page. The browser encrypts each file chunk by chunk and sends the chunks to
 * UploadChunkController (resources/js/share-uploader.js); this component registers the files
 * into a pending share, lists them and completes the share with its options.
 */
#[Layout('layouts.app')]
class FileUploader extends Component
{
    /** The pending share this page uploads into: created with the first file, one per page load. */
    #[Locked]
    public ?string $pendingToken = null;

    public bool $usePassword = false;

    public string $password = '';

    public string $password_confirmation = '';

    public string $expiration = '7d';

    public ?int $maxDownloads = null;

    public function mount(): void
    {
        $this->expiration = Setting::get('default_expiration', '7d') ?: '7d';
    }

    /**
     * Register the files a visitor chose and hand the browser what it encrypts and sends them
     * with. A file an admin limit refuses gets `null` in its place and the reason under `files`.
     *
     * @param  array<int, array{name?: mixed, size?: mixed, path?: mixed}>  $files
     * @return array<int, array{id: int, url: string, key: string, noncePrefix: string, chunkSize: int, chunkCount: int}|null>
     */
    public function registerFiles(array $files, ShareService $shareService): array
    {
        $this->resetErrorBag('files');

        $targets = [];

        foreach ($files as $file) {
            try {
                $shareFile = $shareService->registerFile(
                    $this->pendingShare(),
                    (string) ($file['name'] ?? ''),
                    (int) ($file['size'] ?? -1),
                    isset($file['path']) ? (string) $file['path'] : null,
                );
            } catch (ValidationException $e) {
                if (! $this->getErrorBag()->has('files')) {
                    $this->addError('files', $e->errors()['files'][0]);
                }

                $targets[] = null;

                continue;
            }

            if ($this->pendingToken !== $shareFile->share->token) {
                $this->pendingToken = $shareFile->share->token;
                session()->push('pending_shares', $this->pendingToken);
            }

            $header = $shareService->readHeader($shareFile);

            $targets[] = [
                'id' => $shareFile->id,
                'url' => Str::beforeLast(route('upload.chunk', ['shareFile' => $shareFile, 'index' => 0]), '/'),
                'key' => $shareFile->share->encryption_key,
                'noncePrefix' => bin2hex($header['noncePrefix']),
                'chunkSize' => $header['chunkSize'],
                'chunkCount' => $header['chunkCount'],
            ];
        }

        return $targets;
    }

    /**
     * Take files out of the pending share, whether or not their upload finished.
     *
     * @param  array<int, mixed>  $fileIds
     */
    public function removeFiles(array $fileIds, ShareService $shareService): void
    {
        $files = $this->pendingShare()?->files()->whereIn('id', array_map('intval', $fileIds))->get() ?? [];

        foreach ($files as $file) {
            $shareService->removeFile($file);
        }

        $this->resetErrorBag('files');
    }

    /**
     * Fill in a generated password as protection is switched on, when the admin chose "Prefilled".
     * A password already in the field stays.
     */
    public function updatedUsePassword(bool $value): void
    {
        $passwordGenerator = app(PasswordGeneratorService::class);

        if ($value && $this->password === '' && $passwordGenerator->mode() === 'prefill') {
            $this->password = $passwordGenerator->generate();
        }
    }

    public function generatePassword(PasswordGeneratorService $passwordGenerator): void
    {
        if ($passwordGenerator->mode() === 'off') {
            return;
        }

        $this->password = $passwordGenerator->generate();
        $this->resetErrorBag('password');
    }

    public function createShare(ShareService $shareService): void
    {
        $rules = [];

        if (! Setting::get('allow_never_expire', false)) {
            $rules['expiration'] = ['required', 'string', 'in:1h,24h,48h,7d,14d,30d'];
        }

        if ($this->usePassword) {
            $rules['password'] = ['required', 'string', 'min:8'];
        }

        if ($rules !== []) {
            $this->validate($rules, [
                'expiration.required' => __('An expiration time is required.'),
            ]);
        }

        $pendingShare = $this->pendingShare();

        if ($pendingShare === null) {
            $this->addError('files', __('Please select at least one file to upload.'));

            return;
        }

        $share = $shareService->completeShare($pendingShare, [
            'password' => $this->usePassword ? $this->password : null,
            'expires_at' => match ($this->expiration) {
                '1h' => now()->addHour(),
                '24h' => now()->addDay(),
                '48h' => now()->addDays(2),
                '7d' => now()->addWeek(),
                '14d' => now()->addDays(14),
                '30d' => now()->addMonth(),
                default => null,
            },
            'max_downloads' => $this->maxDownloads ?: null,
        ]);

        session()->put('pending_shares', array_values(array_diff(session('pending_shares', []), [$share->token])));

        // The page the upload leads to offers the password once more, next to the link; it is
        // never stored in the clear, so this flash is the only way it gets there.
        if ($this->usePassword) {
            session()->flash('share_password', [
                'token' => $share->token,
                'password' => Crypt::encryptString($this->password),
            ]);
        }

        $this->redirect(route('share.created', $share), navigate: true);
    }

    public function render(): mixed
    {
        $shareService = app(ShareService::class);
        $pendingFiles = $this->pendingShare()?->files()->orderBy('id')->get() ?? collect();

        return view('livewire.file-uploader', [
            'pendingFiles' => $pendingFiles,
            'allFilesUploaded' => $pendingFiles->isNotEmpty() && $pendingFiles->every(fn ($file): bool => $file->completed_at !== null),
            'isStorageFull' => $shareService->isStorageFull(),
            'siteTitle' => Setting::get('site_title'),
            'siteDescription' => Setting::get('site_description'),
            'siteLogo' => Setting::get('site_logo'),
            'allowNeverExpire' => (bool) Setting::get('allow_never_expire', false),
            'passwordGeneratorMode' => app(PasswordGeneratorService::class)->mode(),
        ]);
    }

    /**
     * This page's pending share, while it is still pending and this session started it.
     */
    private function pendingShare(): ?Share
    {
        if ($this->pendingToken === null || ! in_array($this->pendingToken, session('pending_shares', []), true)) {
            return null;
        }

        return Share::query()->where('token', $this->pendingToken)->whereNull('completed_at')->first();
    }
}