<?php

namespace App\Http\Resources\FileAttachment;

use Illuminate\Http\Request;
use Illuminate\Http\Resources\Json\JsonResource;

class FileAttachmentResource extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @return array<string, mixed>
     */
    public function toArray(Request $request): array
    {
        return [
            'id' => $this->id,
            'file_id' => $this->file_id,
            'label' => $this->label,
            'sort_order' => $this->sort_order,
            'attachable_type' => $this->attachable_type,
            'attachable_id' => $this->attachable_id,
            'created_at' => $this->created_at->format('Y-m-d H:i:s'),
            'updated_at' => $this->updated_at->format('Y-m-d H:i:s'),

            // File information
            'file' => $this->whenLoaded('file', function () {
                return [
                    'id' => $this->file->id,
                    'name' => $this->file->name,
                    'original_name' => $this->file->original_name ?? $this->file->name,
                    'path' => $this->file->path,
                    'mime_type' => $this->file->mime_type,
                    'size' => $this->file->size,
                    'size_formatted' => $this->formatFileSize($this->file->size ?? 0),
                    'extension' => pathinfo($this->file->name, PATHINFO_EXTENSION),
                    'download_url' => url('/api/files/' . $this->file->id . '/download'),
                ];
            }),

            // Attachable model information
            'attachable' => $this->whenLoaded('attachable', function () {
                return [
                    'id' => $this->attachable->id,
                    'type' => class_basename($this->attachable),
                    'name' => $this->getAttachableName(),
                ];
            }),

            // Helper methods
            'is_for_intervention' => $this->isForIntervention(),
            'is_for_client' => $this->isForClient(),
            'is_for_deceased' => $this->isForDeceased(),
            'download_url' => $this->downloadUrl,
        ];
    }

    /**
     * Format file size in human readable format
     */
    private function formatFileSize(int $bytes): string
    {
        $units = ['B', 'KB', 'MB', 'GB', 'TB'];
        $bytes = max($bytes, 0);
        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
        $pow = min($pow, count($units) - 1);

        $bytes /= (1 << (10 * $pow));

        return round($bytes, 2) . ' ' . $units[$pow];
    }

    /**
     * Get the display name of the attached model
     */
    private function getAttachableName(): string
    {
        if (!$this->attachable) {
            return 'Unknown';
        }

        return match (get_class($this->attachable)) {
            \App\Models\Intervention::class => $this->attachable->title ?? "Intervention #{$this->attachable->id}",
            \App\Models\Client::class => $this->attachable->name ?? "Client #{$this->attachable->id}",
            \App\Models\Deceased::class => $this->attachable->name ?? "Deceased #{$this->attachable->id}",
            default => 'Unknown Model'
        };
    }
}