<?php

namespace App\Support;

use App\Models\Business\CourierAgreementSignature;
use App\Services\Esign\EsignClient;
use Illuminate\Support\Facades\Storage;
use RuntimeException;

final class CourierAgreementFileArchive
{
    public function sourcePath(CourierAgreementSignature $signature): string
    {
        $path = trim((string) $signature->source_pdf_path);
        if ($path === '') {
            throw new RuntimeException('该历史任务没有保存签署原文路径，无法下载。');
        }

        $disk = Storage::disk('uploads');
        if ($disk->exists($path)) {
            return $path;
        }

        if (blank($signature->esign_file_id)) {
            throw new RuntimeException('本地历史文件缺失，且该任务未成功上传至 E 签宝，无法自动恢复。');
        }

        $expectedHash = strtolower(trim((string) $signature->source_pdf_sha256));
        if (preg_match('/^[a-f0-9]{64}$/', $expectedHash) !== 1) {
            throw new RuntimeException('本地历史文件缺失，且没有可用于校验的原文件摘要，已停止自动恢复。');
        }

        $bytes = app(EsignClient::class)->downloadUploadedPdf((string) $signature->esign_file_id);
        if (! str_starts_with($bytes, '%PDF-')) {
            throw new RuntimeException('E 签宝返回的历史原文件不是有效 PDF，已停止自动恢复。');
        }

        if (! hash_equals($expectedHash, hash('sha256', $bytes))) {
            throw new RuntimeException('E 签宝历史原文件与系统留存摘要不一致，已停止自动恢复。');
        }

        if (! $disk->put($path, $bytes)) {
            throw new RuntimeException('历史原文件无法写回私有业务存储。');
        }

        $storedBytes = $disk->get($path);
        if (! str_starts_with($storedBytes, '%PDF-')
            || ! hash_equals($expectedHash, hash('sha256', $storedBytes))) {
            $disk->delete($path);
            throw new RuntimeException('历史原文件写回后校验失败，已移除不完整文件。');
        }

        return $path;
    }
}