<?php

declare(strict_types=1);

namespace Modules\Helpdesk\Services;

use Illuminate\Http\UploadedFile;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\Storage;
use Livewire\Features\SupportFileUploads\TemporaryUploadedFile;
use Modules\Helpdesk\Models\Attachment;
use Modules\Helpdesk\Models\Comment;
use Modules\Helpdesk\Models\Ticket;

final class AttachmentService
{
    /**
     * Store multiple Helpdesk attachments against a ticket or comment.
     *
     * Livewire create/comment forms pass TemporaryUploadedFile instances, while
     * controller endpoints pass Symfony/Laravel UploadedFile instances. Both
     * are supported here so uploads are never silently skipped on ticket create.
     *
     * @param  array<int|string, mixed>  $files
     */
    public function storeMany(Ticket $ticket, array $files, int $userId, ?Comment $comment = null): void
    {
        foreach ($files as $file) {
            if (! $this->isSupportedUpload($file)) {
                continue;
            }

            $disk = (string) config('helpdesk.disk', 'public');
            $originalName = $this->originalName($file);
            $mimeType = $this->mimeType($file);
            $size = $this->size($file);
            $path = $file->store('tickets/'.$ticket->id, $disk);

            if (! is_string($path) || $path === '') {
                continue;
            }

            if ($size === 0) {
                $size = (int) Storage::disk($disk)->size($path);
            }

            Attachment::query()->create($this->attachmentAttributes(
                ticket: $ticket,
                comment: $comment,
                userId: $userId,
                disk: $disk,
                path: $path,
                originalName: $originalName,
                mimeType: $mimeType,
                size: $size,
            ));
        }
    }

    /**
     * Delete a stored attachment and its backing file.
     */
    public function delete(Attachment $attachment): void
    {
        Storage::disk($attachment->disk)->delete($attachment->path);
        $attachment->delete();
    }

    /**
     * Build attachment attributes while remaining compatible with older databases.
     *
     * @return array<string, mixed>
     */
    private function attachmentAttributes(Ticket $ticket, ?Comment $comment, int $userId, string $disk, string $path, string $originalName, string $mimeType, int $size): array
    {
        $attributes = [
            'ticket_id' => $ticket->id,
            'comment_id' => $comment?->id,
            'user_id' => $userId,
            'disk' => $disk,
            'path' => $path,
            'original_name' => $originalName,
            'mime_type' => $mimeType,
            'size' => $size,
        ];

        if (Schema::hasColumn('helpdesk_attachments', 'extension')) {
            $attributes['extension'] = strtolower((string) pathinfo($originalName, PATHINFO_EXTENSION));
        }

        if (Schema::hasColumn('helpdesk_attachments', 'category')) {
            $attributes['category'] = $this->categoryFor($originalName, $mimeType);
        }

        if (Schema::hasColumn('helpdesk_attachments', 'checksum_sha256') && Storage::disk($disk)->exists($path)) {
            $stream = Storage::disk($disk)->readStream($path);

            if (is_resource($stream)) {
                $context = hash_init('sha256');
                hash_update_stream($context, $stream);
                $attributes['checksum_sha256'] = hash_final($context);
                fclose($stream);
            }
        }

        return $attributes;
    }

    /**
     * Categorise uploaded files for icons, previews and safe code viewing.
     */
    private function categoryFor(string $originalName, string $mimeType): string
    {
        $extension = strtolower((string) pathinfo($originalName, PATHINFO_EXTENSION));

        if (str_starts_with($mimeType, 'image/') || in_array($extension, ['png', 'jpg', 'jpeg', 'webp', 'gif'], true)) {
            return 'image';
        }

        if ($extension === 'pdf' || $mimeType === 'application/pdf') {
            return 'pdf';
        }

        if (in_array($extension, ['zip', 'tar', 'gz', '7z', 'rar'], true)) {
            return 'archive';
        }

        if (in_array($extension, config('helpdesk.allowed_source_extensions', []), true)) {
            return 'source';
        }

        return 'file';
    }

    /**
     * Soft-delete a stored attachment while retaining audit metadata.
     */
    public function softDelete(Attachment $attachment, int $userId): void
    {
        DB::table('helpdesk_attachments')
            ->where('id', $attachment->id)
            ->update(array_filter([
                'deleted_at' => now(),
                'deleted_by' => Schema::hasColumn('helpdesk_attachments', 'deleted_by') ? $userId : null,
            ], static fn (mixed $value): bool => $value !== null));
    }

    /**
     * Determine whether the value is a storeable uploaded file.
     */
    private function isSupportedUpload(mixed $file): bool
    {
        if ($file instanceof TemporaryUploadedFile) {
            return true;
        }

        return $file instanceof UploadedFile && $file->isValid();
    }

    /**
     * Return the uploaded file's original client filename.
     */
    private function originalName(mixed $file): string
    {
        return (string) $file->getClientOriginalName();
    }

    /**
     * Return the uploaded file's reported mime type.
     */
    private function mimeType(mixed $file): string
    {
        return (string) ($file->getClientMimeType() ?: $file->getMimeType() ?: 'application/octet-stream');
    }

    /**
     * Return the uploaded file's byte size.
     */
    private function size(mixed $file): int
    {
        return (int) ($file->getSize() ?: 0);
    }
}