<?php

declare(strict_types=1);

namespace App\Actions;

use App\Enums\CrawlOutcomeEnum;
use App\ValueObjects\FetchResult;
use GuzzleHttp\Exception\ConnectException;
use Illuminate\Http\Client\ConnectionException;
use Illuminate\Http\Client\Factory;
use Illuminate\Http\Client\Response;

class FetchPageAction
{
    public function __construct(
        private Factory $http,
    ) {}

    public function __invoke(string $url): FetchResult
    {
        try {
            $response = $this->http
                ->timeout(config('crawler.timeout'))
                ->withHeaders([
                    'User-Agent' => config('crawler.user_agent'),
                    'Accept' => 'text/html',
                ])
                ->withOptions([
                    'allow_redirects' => ['max' => config('crawler.max_redirects')],
                ])
                ->get($url);

        } catch (ConnectionException|ConnectException $e) {
            return $this->failureResult($e);
        }

        [$outcome, $error] = $this->validateResponse($response);

        return new FetchResult(
            outcome: $outcome,
            statusCode: $response->status(),
            finalUrl: $url,
            title: null,
            extractedText: null,
            outboundLinks: collect(),
            wordCount: null,
            errorMessage: $error ?? null,
        );
    }

    private function validateResponse(Response $response): array
    {
        $status = $response->status();
        $statusStart = substr((string) $status, 0, 1);

        if ($statusStart === '4') {
            return [CrawlOutcomeEnum::Blocked4xx, "HTTP {$status}"];
        }

        if (str_starts_with((string) $status, '5')) {
            return [CrawlOutcomeEnum::Blocked5xx, "HTTP {$status}"];
        }

        $contentType = $response->header('Content-Type');
        if (! str_starts_with($contentType, 'text/html')) {
            return [CrawlOutcomeEnum::Rejected, "Unsupported file type: {$contentType}"];
        }

        return [CrawlOutcomeEnum::Success, null];
    }

    private function failureResult(ConnectionException|ConnectException $e): FetchResult
    {
        $guzzleException = $e instanceof ConnectException
            ? $e
            : ($e->getPrevious() instanceof ConnectException
                ? $e->getPrevious()
                : null);

        $errno = $guzzleException?->getHandlerContext()['errno'] ?? null;

        $outcome = $errno === CURLE_OPERATION_TIMEDOUT
            ? CrawlOutcomeEnum::Timeout
            : CrawlOutcomeEnum::Failed;

        return new FetchResult(
            outcome: $outcome,
            statusCode: null,
            finalUrl: null,
            title: null,
            extractedText: null,
            outboundLinks: collect(),
            wordCount: null,
            errorMessage: $e->getMessage(),
        );
    }
}