<?php

declare(strict_types=1);

namespace App\Services\Pdf;

final class PdfRenderingGateway
{
    public function __construct(
        private readonly PdfRendererClient $client,
    ) {}

    public function healthCheck(?string $correlationId = null): PdfRenderResult
    {
        if (! $this->isEnabled()) {
            return PdfRenderResult::failure(
                PdfRenderResult::RENDERER_DISABLED,
                'PDF renderer is disabled.',
                correlationId: $correlationId,
            );
        }

        return $this->client->healthCheck($correlationId);
    }

    public function renderHtml(PdfRenderRequest $request): PdfRenderResult
    {
        if (! $this->isEnabled()) {
            return PdfRenderResult::failure(
                PdfRenderResult::RENDERER_DISABLED,
                'PDF renderer is disabled.',
                correlationId: $request->correlationId,
            );
        }

        if (trim($request->html) === '') {
            return PdfRenderResult::failure(
                PdfRenderResult::INVALID_REQUEST,
                'PDF renderer requires server-generated HTML.',
                correlationId: $request->correlationId,
            );
        }

        if (strlen($request->html) > $this->maxHtmlBytes()) {
            return PdfRenderResult::failure(
                PdfRenderResult::PAYLOAD_TOO_LARGE,
                'PDF HTML payload exceeds the configured size limit.',
                correlationId: $request->correlationId,
            );
        }

        foreach ($request->assets as $filename => $contents) {
            if (! $this->isFlatAssetFilename((string) $filename)) {
                return PdfRenderResult::failure(
                    PdfRenderResult::INVALID_ASSET,
                    'PDF assets must use flat relative filenames.',
                    correlationId: $request->correlationId,
                );
            }

            if (strlen($contents) > $this->maxAssetBytes()) {
                return PdfRenderResult::failure(
                    PdfRenderResult::PAYLOAD_TOO_LARGE,
                    'PDF asset payload exceeds the configured size limit.',
                    correlationId: $request->correlationId,
                );
            }
        }

        $result = $this->client->render($request);

        if ($result->successful() && $result->pdfBytes !== null && strlen($result->pdfBytes) > $this->maxOutputBytes()) {
            return PdfRenderResult::failure(
                PdfRenderResult::OUTPUT_TOO_LARGE,
                'PDF renderer output exceeds the configured size limit.',
                statusCode: $result->statusCode,
                correlationId: $result->correlationId,
            );
        }

        return $result;
    }

    private function isEnabled(): bool
    {
        return (bool) config('tenantpilot.pdf_renderer.enabled', false)
            && config('tenantpilot.pdf_renderer.driver', 'gotenberg') === 'gotenberg';
    }

    private function maxHtmlBytes(): int
    {
        return max(1, (int) config('tenantpilot.pdf_renderer.max_html_bytes', 1024 * 1024));
    }

    private function maxAssetBytes(): int
    {
        return max(1, (int) config('tenantpilot.pdf_renderer.max_asset_bytes', 2 * 1024 * 1024));
    }

    private function maxOutputBytes(): int
    {
        return max(1, (int) config('tenantpilot.pdf_renderer.max_output_bytes', 10 * 1024 * 1024));
    }

    private function isFlatAssetFilename(string $filename): bool
    {
        $filename = trim($filename);

        return $filename !== ''
            && $filename === basename($filename)
            && ! str_contains($filename, "\0")
            && $filename !== 'index.html';
    }
}