<?php

declare(strict_types=1);

namespace Mummert\SurveyBundle\Service;

use Contao\Config;
use Mummert\SurveyBundle\Model\SurveyModel;
use Symfony\Component\HttpClient\Exception\TransportExceptionInterface;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Exception\BadGatewayHttpException;
use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
use Symfony\Component\Mime\Part\DataPart;
use Symfony\Component\Mime\Part\Multipart\FormDataPart;
use Symfony\Contracts\HttpClient\HttpClientInterface;
use Twig\Environment;

final class SurveyResultsPdfService
{
    public function __construct(
        private readonly Environment $twig,
        private readonly HttpClientInterface $httpClient,
    ) {
    }

    public function isConfigured(): bool
    {
        return null !== $this->getGotenbergBaseUrl();
    }

    /**
     * @param list<array<string, mixed>> $questionResults
     */
    public function createPdfExportResponse(SurveyModel $survey, int $completedSubmissionCount, array $questionResults): Response
    {
        $gotenbergBaseUrl = $this->getGotenbergBaseUrl();

        if (null === $gotenbergBaseUrl) {
            throw new BadRequestHttpException('Es wurde keine Gotenberg-URL in den Einstellungen hinterlegt.');
        }

        $html = $this->renderTemplate(
            $survey,
            $completedSubmissionCount,
            $this->prepareQuestionResults($questionResults),
        );
        $filename = $this->buildFilename((string) $survey->title);
        $pdfContent = $this->requestPdfFromGotenberg($gotenbergBaseUrl, $html, $filename);

        return new Response(
            $pdfContent,
            Response::HTTP_OK,
            [
                'Content-Type' => 'application/pdf',
                'Content-Disposition' => sprintf('attachment; filename="%s"', $filename),
            ],
        );
    }

    private function getGotenbergBaseUrl(): ?string
    {
        $url = trim((string) Config::get('surveyGotenbergUrl'));

        return '' !== $url ? rtrim($url, '/') : null;
    }

    private function requestPdfFromGotenberg(string $gotenbergBaseUrl, string $html, string $filename): string
    {
        $formData = new FormDataPart([
            'files' => new DataPart($html, 'index.html', 'text/html'),
            'paperWidth' => '8.27',
            'paperHeight' => '11.7',
            'marginTop' => '0.5',
            'marginBottom' => '0.5',
            'marginLeft' => '0.5',
            'marginRight' => '0.5',
            'emulatedMediaType' => 'screen',
            'printBackground' => 'true',
            'failOnConsoleExceptions' => 'true',
            'failOnResourceLoadingFailed' => 'true',
        ]);

        $headers = $formData->getPreparedHeaders()->toArray();
        $headers['Gotenberg-Output-Filename'] = pathinfo($filename, PATHINFO_FILENAME);

        try {
            $response = $this->httpClient->request('POST', $gotenbergBaseUrl.'/forms/chromium/convert/html', [
                'headers' => $headers,
                'body' => $formData->bodyToIterable(),
                'timeout' => 60,
            ]);
        } catch (TransportExceptionInterface $exception) {
            throw new BadGatewayHttpException('Die Gotenberg-Instanz konnte nicht erreicht werden.', $exception);
        }

        $statusCode = $response->getStatusCode();
        $content = $response->getContent(false);

        if (Response::HTTP_OK !== $statusCode) {
            $message = trim(strip_tags(substr($content, 0, 500)));

            throw new BadGatewayHttpException(sprintf(
                'Die Gotenberg-Instanz hat den PDF-Export mit HTTP %d abgelehnt%s',
                $statusCode,
                '' !== $message ? ': '.$message : '.'
            ));
        }

        return $content;
    }

    /**
     * @param list<array<string, mixed>> $questionResults
     *
     * @return list<array<string, mixed>>
     */
    private function prepareQuestionResults(array $questionResults): array
    {
        $preparedResults = [];

        foreach ($questionResults as $questionResult) {
            $questionResult['pdfChartType'] = (string) (($questionResult['chart']['type'] ?? '') ?: '');
            $questionResult['pdfChartDataUri'] = $this->buildChartDataUri($questionResult);
            $questionResult['pdfChartLegend'] = $this->buildChartLegend($questionResult);
            $preparedResults[] = $questionResult;
        }

        return $preparedResults;
    }

    /**
     * @param array<string, mixed> $questionResult
     *
        * @return list<array{label:string,fillColor:string,borderColor:string,count:int,percentage:int}>
     */
    private function buildChartLegend(array $questionResult): array
    {
        $chart = $questionResult['chart'] ?? null;
        $chartType = is_array($chart) ? (string) ($chart['type'] ?? '') : '';
        $sourceRows = match ($chartType) {
            'pie' => $questionResult['options'] ?? $questionResult['responseSummary'] ?? [],
            'line' => $questionResult['distribution'] ?? [],
            // Freitext hat kein Diagramm: Antwort-Häufigkeiten wie in der Online-Ansicht zeigen.
            default => $questionResult['responseSummary'] ?? [],
        };

        if (!is_array($sourceRows) || [] === $sourceRows) {
            return [];
        }

        $dataset = is_array($chart) ? ($chart['data']['datasets'][0] ?? []) : [];
        $fillColors = match ($chartType) {
            'pie' => is_array($dataset['backgroundColor'] ?? null) ? $dataset['backgroundColor'] : [],
            'line' => is_array($dataset['pointBackgroundColor'] ?? null) ? $dataset['pointBackgroundColor'] : [],
            default => [],
        };
        $borderColors = match ($chartType) {
            'pie' => is_array($dataset['borderColor'] ?? null) ? $dataset['borderColor'] : [],
            'line' => is_array($dataset['pointBackgroundColor'] ?? null) ? $dataset['pointBackgroundColor'] : [],
            default => [],
        };

        $legend = [];

        foreach (array_values($sourceRows) as $index => $row) {
            if (!is_array($row)) {
                continue;
            }

            $legend[] = [
                'label' => (string) ($row['label'] ?? ''),
                'fillColor' => (string) ($fillColors[$index] ?? '#D3E4F1'),
                'borderColor' => (string) ($borderColors[$index] ?? '#0064AD'),
                'count' => (int) ($row['count'] ?? 0),
                'percentage' => (int) ($row['percentage'] ?? 0),
            ];
        }

        return $legend;
    }

    private function renderTemplate(SurveyModel $survey, int $completedSubmissionCount, array $questionResults): string
    {
        $templatePath = __DIR__.'/../Resources/views/pdf/survey_results.html.twig';
        $templateContent = file_get_contents($templatePath);

        if (false === $templateContent) {
            throw new \RuntimeException('Die PDF-Template-Datei konnte nicht gelesen werden: '.$templatePath);
        }

        return $this->twig->createTemplate($templateContent)->render([
            'survey' => $survey,
            'completedSubmissionCount' => $completedSubmissionCount,
            'questionResults' => $questionResults,
            'exportedAt' => (new \DateTimeImmutable())->format('d.m.Y H:i'),
            'documentTitle' => $this->buildDocumentTitle((string) $survey->title),
            'fontFaceCss' => $this->buildEmbeddedFontFaceCss(),
        ]);
    }

    private function buildDocumentTitle(string $surveyTitle): string
    {
        $title = trim(strip_tags($surveyTitle));

        return '' !== $title ? $title.' Ergebnisse' : 'Umfrage Ergebnisse';
    }

    private function buildEmbeddedFontFaceCss(): string
    {
        $fontDefinitions = [
            ['family' => 'PT Sans Narrow', 'weight' => 400, 'path' => __DIR__.'/../../public/fonts/PTSansNarrow-Regular.woff2'],
            ['family' => 'PT Sans Narrow', 'weight' => 700, 'path' => __DIR__.'/../../public/fonts/PTSansNarrow-Bold.woff2'],
            ['family' => 'Blogger Sans', 'weight' => 500, 'path' => __DIR__.'/../../public/fonts/Blogger Sans-Medium.woff2'],
        ];

        $rules = [];

        foreach ($fontDefinitions as $fontDefinition) {
            $fontContent = @file_get_contents($fontDefinition['path']);

            if (false === $fontContent) {
                continue;
            }

            $rules[] = sprintf(
                '@font-face { font-family: "%s"; src: url("data:font/woff2;base64,%s") format("woff2"); font-weight: %d; font-style: normal; font-display: swap; }',
                $fontDefinition['family'],
                base64_encode($fontContent),
                $fontDefinition['weight'],
            );
        }

        return implode("\n", $rules);
    }

    /**
     * @param array<string, mixed> $questionResult
     */
    private function buildChartDataUri(array $questionResult): ?string
    {
        $chart = $questionResult['chart'] ?? null;

        if (!is_array($chart)) {
            return null;
        }

        $svg = match ((string) ($chart['type'] ?? '')) {
            'pie' => $this->buildPieChartSvg($questionResult, $chart),
            'line' => $this->buildLineChartSvg($questionResult, $chart),
            default => null,
        };

        if (null === $svg) {
            return null;
        }

        return 'data:image/svg+xml;base64,'.base64_encode($svg);
    }

    /**
     * @param array<string, mixed> $questionResult
     * @param array<string, mixed> $chart
     */
    private function buildPieChartSvg(array $questionResult, array $chart): ?string
    {
        $options = $questionResult['options'] ?? $questionResult['responseSummary'] ?? [];

        if (!is_array($options) || [] === $options) {
            return $this->buildEmptyChartSvg('Noch keine Daten');
        }

        $dataset = $chart['data']['datasets'][0] ?? null;
        $fillColors = is_array($dataset['backgroundColor'] ?? null) ? $dataset['backgroundColor'] : [];
        $borderColors = is_array($dataset['borderColor'] ?? null) ? $dataset['borderColor'] : [];
        $counts = array_map(static fn (array $option): int => (int) ($option['count'] ?? 0), $options);
        $total = array_sum($counts);

        if ($total <= 0) {
            return $this->buildEmptyChartSvg('Noch keine Daten');
        }

        $centerX = 140.0;
        $centerY = 140.0;
        $radius = 88.0;
        $startAngle = -90.0;
        $segments = [];

        foreach ($options as $index => $option) {
            $count = (int) ($option['count'] ?? 0);

            if ($count <= 0) {
                continue;
            }

            $sweepAngle = ($count / $total) * 360.0;
            $endAngle = $startAngle + $sweepAngle;
            $largeArcFlag = $sweepAngle > 180.0 ? 1 : 0;

            $startPoint = $this->polarToCartesian($centerX, $centerY, $radius, $startAngle);
            $endPoint = $this->polarToCartesian($centerX, $centerY, $radius, $endAngle);
            $fill = (string) ($fillColors[$index] ?? '#D3E4F1');
            $stroke = (string) ($borderColors[$index] ?? '#0064AD');

            $segments[] = sprintf(
                '<path d="M %.2f %.2f L %.2f %.2f A %.2f %.2f 0 %d 1 %.2f %.2f Z" fill="%s" stroke="%s" stroke-width="2" />',
                $centerX,
                $centerY,
                $startPoint['x'],
                $startPoint['y'],
                $radius,
                $radius,
                $largeArcFlag,
                $endPoint['x'],
                $endPoint['y'],
                $this->escapeXml($fill),
                $this->escapeXml($stroke),
            );

            $startAngle = $endAngle;
        }

        return sprintf(
            '<svg xmlns="http://www.w3.org/2000/svg" width="280" height="280" viewBox="0 0 280 280" role="img" aria-label="Kreisdiagramm"><rect width="280" height="280" rx="24" fill="#ffffff"/><circle cx="140" cy="140" r="108" fill="#f6f8fb"/><g>%s</g><circle cx="140" cy="140" r="26" fill="#ffffff"/><text x="140" y="146" text-anchor="middle" font-size="18" font-family="DejaVu Sans" fill="#222222">%d</text></svg>',
            implode('', $segments),
            $total,
        );
    }

    /**
     * @param array<string, mixed> $questionResult
     * @param array<string, mixed> $chart
     */
    private function buildLineChartSvg(array $questionResult, array $chart): ?string
    {
        $distribution = $questionResult['distribution'] ?? [];

        if (!is_array($distribution) || [] === $distribution) {
            return $this->buildEmptyChartSvg('Noch keine Bewertungen');
        }

        $labels = array_map(static fn (array $row): string => (string) ($row['label'] ?? ''), $distribution);
        $values = array_map(static fn (array $row): int => (int) ($row['count'] ?? 0), $distribution);
        $maxValue = max(1, max($values));

        $width = 560.0;
        $height = 280.0;
        $paddingLeft = 58.0;
        $paddingRight = 22.0;
        $paddingTop = 24.0;
        $paddingBottom = 44.0;
        $plotWidth = $width - $paddingLeft - $paddingRight;
        $plotHeight = $height - $paddingTop - $paddingBottom;
        $steps = max(1, count($values) - 1);
        $dataset = is_array($chart['data']['datasets'][0] ?? null) ? $chart['data']['datasets'][0] : [];
        $lineColor = (string) ($dataset['borderColor'] ?? '#0064AD');
        $areaFill = (string) ($dataset['backgroundColor'] ?? 'rgba(236, 124, 50, 0.12)');
        $pointColors = is_array($chart['data']['datasets'][0]['pointBackgroundColor'] ?? null) ? $chart['data']['datasets'][0]['pointBackgroundColor'] : [];
        $polylinePoints = [];
        $areaPolylinePoints = [];
        $pointCircles = [];
        $xLabels = [];
        $yGrid = [];

        // Große Skalen (z. B. Alter 1–100): X-Beschriftung ausdünnen und die
        // Punkt-Marker verkleinern bzw. weglassen, damit das Diagramm lesbar bleibt.
        $pointCount = count($values);
        $labelStep = max(1, (int) ceil($pointCount / 12));
        $lastIndex = $pointCount - 1;
        $pointRadius = $pointCount > 40 ? 0.0 : ($pointCount > 20 ? 3.0 : 5.5);

        $yStep = max(1, (int) ceil($maxValue / 6));

        for ($tick = 0; $tick <= $maxValue; $tick += $yStep) {
            $ratio = $maxValue > 0 ? $tick / $maxValue : 0;
            $y = $paddingTop + $plotHeight - ($ratio * $plotHeight);
            $yGrid[] = sprintf('<line x1="%.2f" y1="%.2f" x2="%.2f" y2="%.2f" stroke="#d7dee8" stroke-width="1" />', $paddingLeft, $y, $width - $paddingRight, $y);
            $yGrid[] = sprintf('<text x="%.2f" y="%.2f" text-anchor="end" font-size="11" font-family="DejaVu Sans" fill="#555e68">%d</text>', $paddingLeft - 8, $y + 4, $tick);
        }

        foreach ($values as $index => $value) {
            $x = $paddingLeft + ($plotWidth * ($index / $steps));
            $y = $paddingTop + $plotHeight - (($value / $maxValue) * $plotHeight);
            $polylinePoints[] = sprintf('%.2f,%.2f', $x, $y);
            $areaPolylinePoints[] = sprintf('%.2f,%.2f', $x, $y);

            if ($pointRadius > 0.0) {
                $pointCircles[] = sprintf('<circle cx="%.2f" cy="%.2f" r="%.1f" fill="%s" stroke="#ffffff" stroke-width="2" />', $x, $y, $pointRadius, $this->escapeXml((string) ($pointColors[$index] ?? '#EC7C32')));
            }

            if (0 === $index % $labelStep || $index === $lastIndex) {
                $xLabels[] = sprintf('<text x="%.2f" y="%.2f" text-anchor="middle" font-size="11" font-family="DejaVu Sans" fill="#555e68">%s</text>', $x, $height - 16, $this->escapeXml($labels[$index]));
            }
        }

        $areaPoints = sprintf(
            '%.2f,%.2f %s %.2f,%.2f',
            $paddingLeft,
            $paddingTop + $plotHeight,
            implode(' ', $areaPolylinePoints),
            $width - $paddingRight,
            $paddingTop + $plotHeight,
        );

        return sprintf(
            '<svg xmlns="http://www.w3.org/2000/svg" width="560" height="280" viewBox="0 0 560 280" role="img" aria-label="Liniendiagramm"><rect width="560" height="280" rx="22" fill="#ffffff"/><rect x="1" y="1" width="558" height="278" rx="22" fill="none" stroke="#e3e7ee"/><g>%s</g><line x1="%.2f" y1="%.2f" x2="%.2f" y2="%.2f" stroke="#8a95a3" stroke-width="1.2"/><line x1="%.2f" y1="%.2f" x2="%.2f" y2="%.2f" stroke="#8a95a3" stroke-width="1.2"/><polygon fill="%s" stroke="none" points="%s"/><polyline fill="none" stroke="%s" stroke-width="3.5" stroke-linejoin="round" stroke-linecap="round" points="%s"/><g>%s</g><g>%s</g></svg>',
            implode('', $yGrid),
            $paddingLeft,
            $paddingTop + $plotHeight,
            $width - $paddingRight,
            $paddingTop + $plotHeight,
            $paddingLeft,
            $paddingTop,
            $paddingLeft,
            $paddingTop + $plotHeight,
            $this->escapeXml($areaFill),
            $areaPoints,
            $this->escapeXml($lineColor),
            implode(' ', $polylinePoints),
            implode('', $pointCircles),
            implode('', $xLabels),
        );
    }

    private function buildEmptyChartSvg(string $label): string
    {
        return sprintf(
            '<svg xmlns="http://www.w3.org/2000/svg" width="560" height="220" viewBox="0 0 560 220" role="img" aria-label="Leeres Diagramm"><rect width="560" height="220" rx="22" fill="#f6f8fb"/><rect x="1" y="1" width="558" height="218" rx="22" fill="none" stroke="#e3e7ee"/><text x="280" y="114" text-anchor="middle" font-size="18" font-family="DejaVu Sans" fill="#555e68">%s</text></svg>',
            $this->escapeXml($label),
        );
    }

    /**
     * @return array{x:float,y:float}
     */
    private function polarToCartesian(float $centerX, float $centerY, float $radius, float $angleInDegrees): array
    {
        $angleInRadians = deg2rad($angleInDegrees);

        return [
            'x' => $centerX + ($radius * cos($angleInRadians)),
            'y' => $centerY + ($radius * sin($angleInRadians)),
        ];
    }

    private function escapeXml(string $value): string
    {
        return htmlspecialchars($value, ENT_QUOTES | ENT_XML1, 'UTF-8');
    }

    private function buildFilename(string $title): string
    {
        $normalizedTitle = preg_replace('/\s+/', '_', trim($title)) ?: 'Umfrage';
        $sanitizedTitle = preg_replace('/[^\pL\pN_-]+/u', '', $normalizedTitle) ?: 'Umfrage';

        return sprintf('%s_Ergebnisse.pdf', trim($sanitizedTitle, '_-'));
    }
}