<?php

declare(strict_types=1);

namespace App\Services\Badges;

use chillerlan\QRCode\Output\QRGdImagePNG;
use chillerlan\QRCode\QRCode;
use chillerlan\QRCode\QROptions;
use Illuminate\Http\Response;
use Throwable;

class BadgePdfService
{
    private const BADGE_WIDTH_IN = 2.36;

    private const BADGE_HEIGHT_IN = 3.54;

    private const CELL_WIDTH_IN = 2.55;

    private const CELL_HEIGHT_IN = 3.85;

    private const PAGE_MARGIN_IN = 0.18;

    /** @var list<string> */
    private array $tempQrFiles = [];

    public function __construct(
        protected BadgeStudentLookupService $studentLookupService,
        protected BadgeUserLookupService $userLookupService,
        protected BadgePrintLogService $printLogService,
        protected BadgeTextFormatter $formatter,
    ) {
    }

    /**
     * Letter landscape PDF, 8 badges per page — students and/or staff (FPDF + QR PNG).
     *
     * @param  int[]  $studentIds  Primary keys on `students.id`
     * @param  int[]  $userIds     Staff/admin/teacher keys on `users.id`
     */
    public function generate(
        array $studentIds,
        array $userIds,
        ?string $schoolYear,
        array $rolesMap = [],
        array $classesMap = [],
        ?int $actorId = null
    ): Response {
        $this->tempQrFiles = [];

        try {
            if (!class_exists('FPDF', false)) {
                require_once base_path('app/ThirdParty/fpdf/fpdf.php');
            }

            $studentIds = $this->formatter->normalizeIds($studentIds);
            $userIds = $this->formatter->normalizeIds($userIds);

            $schoolName = (string) config('badges.school_name', 'Al Rahma Sunday School');
            $motto = (string) config('badges.motto', '');
            $studentRoleLabel = (string) config('badges.role_label', 'Student');
            $footerBlock = $this->footerBlock($schoolName);
            $logoPath = $this->logoFilePath();

            $rowsWithQr = [];

            $students = $this->studentLookupService->fetchForBadges($studentIds, $schoolYear);
            foreach ($students as $row) {
                try {
                    $png = $this->renderQrPng((string) $row['school_id']);
                    $tmpPath = $this->writeTempQrPng($png);
                    if ($tmpPath === null) {
                        continue;
                    }

                    $rowsWithQr[] = array_merge($row, [
                        '_badge_kind' => 'student',
                        'role_subline' => $studentRoleLabel,
                        '_qr_tmp' => $tmpPath,
                    ]);
                } catch (Throwable) {
                    continue;
                }
            }

            foreach ($userIds as $uid) {
                $staffRow = $this->buildStaffBadgeRow((int) $uid, $schoolYear, $rolesMap, $classesMap);
                if ($staffRow === null) {
                    continue;
                }

                try {
                    $qrPayload = (string) ($staffRow['user_id_for_qr'] ?? $staffRow['user_id'] ?? '');
                    if ($qrPayload === '' || !preg_match('/^[A-Za-z0-9_-]+$/', $qrPayload)) {
                        $qrPayload = (string) (int) ($staffRow['user_id'] ?? 0);
                    }

                    $png = $this->renderQrPng($qrPayload);
                    $tmpPath = $this->writeTempQrPng($png);
                    if ($tmpPath === null) {
                        continue;
                    }

                    $rowsWithQr[] = array_merge($staffRow, [
                        '_badge_kind' => 'staff',
                        '_qr_tmp' => $tmpPath,
                    ]);
                } catch (Throwable) {
                    continue;
                }
            }

            $pdf = new \FPDF('L', 'in', 'Letter');
            $pdf->SetAutoPageBreak(false);

            $pages = array_chunk($rowsWithQr, 8);

            if ($pages === []) {
                $pdf->AddPage('L', 'Letter');
                $pdf->SetFont('Helvetica', '', 12);
                $pdf->SetTextColor(0, 0, 0);
                $pdf->SetXY(self::PAGE_MARGIN_IN, self::PAGE_MARGIN_IN);
                $pdf->MultiCell(
                    $pdf->GetPageWidth() - 2 * self::PAGE_MARGIN_IN,
                    0.3,
                    $this->formatter->toPdf(
                        'No valid badges: check user/student ids, roles, or (for students) school id for QR.'
                    ),
                    0,
                    'L'
                );
            } else {
                foreach ($pages as $pageRows) {
                    $pdf->AddPage('L', 'Letter');
                    $slots = array_pad($pageRows, 8, null);

                    for ($gridRow = 0; $gridRow < 2; $gridRow++) {
                        for ($gridCol = 0; $gridCol < 4; $gridCol++) {
                            $idx = ($gridRow * 4) + $gridCol;
                            $row = $slots[$idx];
                            if (!is_array($row) || empty($row['_qr_tmp'])) {
                                continue;
                            }

                            $cellX = self::PAGE_MARGIN_IN + $gridCol * self::CELL_WIDTH_IN;
                            $cellY = self::PAGE_MARGIN_IN + $gridRow * self::CELL_HEIGHT_IN;

                            $badgeX = $cellX + (self::CELL_WIDTH_IN - self::BADGE_WIDTH_IN) / 2;
                            $badgeY = $cellY + (self::CELL_HEIGHT_IN - self::BADGE_HEIGHT_IN) / 2;

                            $this->drawBadge(
                                $pdf,
                                $row,
                                $badgeX,
                                $badgeY,
                                self::BADGE_WIDTH_IN,
                                self::BADGE_HEIGHT_IN,
                                $schoolName,
                                $motto,
                                $studentRoleLabel,
                                $footerBlock,
                                $logoPath
                            );
                        }
                    }
                }
            }

            $binary = $pdf->Output('S');

            $logIds = array_values(array_unique(array_merge($studentIds, $userIds)));
            $this->printLogService->logSafely(
                userIds: $logIds,
                actorId: $actorId,
                schoolYear: $schoolYear,
                rolesMap: $rolesMap,
                classesMap: $classesMap,
                copies: 1
            );

            return response((string) $binary, 200, [
                'Content-Type' => 'application/pdf',
                'Content-Disposition' => 'inline; filename="Badges.pdf"',
            ]);
        } finally {
            foreach ($this->tempQrFiles as $path) {
                if (is_string($path) && $path !== '' && is_file($path)) {
                    @unlink($path);
                }
            }
            $this->tempQrFiles = [];
        }
    }

    /**
     * @param  array<string, mixed>  $rolesMap
     * @param  array<string, mixed>  $classesMap
     * @return ?array<string, mixed>
     */
    protected function buildStaffBadgeRow(
        int $userId,
        ?string $schoolYear,
        array $rolesMap,
        array $classesMap
    ): ?array {
        $info = $this->userLookupService->getUserInfoById($userId, $schoolYear);
        if (!$info || !is_array($info)) {
            return null;
        }

        $resolvedId = (int) ($info['user_id'] ?? $userId);

        $postedRole = $rolesMap[$resolvedId] ?? null;
        $roleResolved = $postedRole !== null
            ? (string) $postedRole
            : $this->formatter->resolveRole($info);

        $roleResolved = $this->formatter->formatRole($roleResolved);
        $info['role_resolved'] = $roleResolved;

        if (!empty($classesMap[$resolvedId])) {
            $info['class_section_name'] = (string) $classesMap[$resolvedId];
        }

        $class = $this->formatter->norm($info['class_section_name'] ?? '');
        $class = $this->formatter->formatClass($class);

        $detectSrc = strtolower($this->formatter->norm(
            ($info['roles'] ?? '') !== '' ? (string) $info['roles'] : $roleResolved
        ));
        $isTeacherish = str_contains($detectSrc, 'teacher') || preg_match('/\bta\b/', $detectSrc);

        if ($isTeacherish && $class !== '') {
            if (strtolower($class) === 'youth') {
                $display = 'Youth ' . $roleResolved;
            } elseif ($class === 'KG') {
                $display = 'KG ' . $roleResolved;
            } else {
                $display = 'Grade ' . $class . ' ' . $roleResolved;
            }
        } elseif ($roleResolved !== '') {
            $display = $roleResolved;
        } elseif ($class !== '') {
            $display = $class;
        } else {
            $display = 'STAFF';
        }

        $gradeCol = $class !== '' ? $class : '—';
        $year = $this->formatter->norm((string) ($info['school_year'] ?? ($schoolYear ?? '')));

        return [
            'user_id' => $resolvedId,
            'user_id_for_qr' => (string) $resolvedId,
            'fullname' => $info['name'] ?? 'STAFF',
            'grade' => $gradeCol,
            'academic_year' => $year !== '' ? $year : '—',
            'school_id' => (string) $resolvedId,
            'role_subline' => $display,
        ];
    }

    protected function writeTempQrPng(string $png): ?string
    {
        $tmpPath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'badge_qr_' . bin2hex(random_bytes(8)) . '.png';
        if (@file_put_contents($tmpPath, $png) === false) {
            return null;
        }

        $this->tempQrFiles[] = $tmpPath;

        return $tmpPath;
    }

    /**
     * @param  array<string, mixed>  $student
     */
    protected function drawBadge(
        \FPDF $pdf,
        array $student,
        float $x,
        float $y,
        float $w,
        float $h,
        string $schoolName,
        string $motto,
        string $defaultStudentRoleLabel,
        string $footerBlock,
        ?string $logoPath
    ): void {
        $kind = (string) ($student['_badge_kind'] ?? 'student');
        $idLabel = $kind === 'staff' ? 'USER ID' : 'SCHOOL ID';

        $blue = [11, 58, 130];
        $blueLight = [27, 76, 160];

        $qrPath = (string) ($student['_qr_tmp'] ?? '');
        $fullName = $this->formatter->toPdf((string) ($student['fullname'] ?? ''));
        $grade = $this->formatter->toPdf((string) ($student['grade'] ?? ''));
        $year = $this->formatter->toPdf((string) ($student['academic_year'] ?? ''));
        $schoolId = $this->formatter->toPdf((string) ($student['school_id'] ?? ''));

        $schoolNamePdf = $this->formatter->toPdf($schoolName);
        $mottoPdf = $this->formatter->toPdf($motto);
        $rolePdf = $this->formatter->toPdf((string) ($student['role_subline'] ?? $defaultStudentRoleLabel));

        $pdf->SetDrawColor($blue[0], $blue[1], $blue[2]);
        $pdf->SetLineWidth(0.003);
        $pdf->Rect($x, $y, $w, $h);

        $headerH = 0.55;
        $footerH = 0.38;

        $pdf->SetFillColor($blue[0], $blue[1], $blue[2]);
        $pdf->Rect($x, $y, $w, $headerH, 'F');

        $logoSize = 0.12;
        if ($logoPath !== null && is_readable($logoPath)) {
            try {
                $pdf->Image($logoPath, $x + $w / 2 - $logoSize / 2, $y + 0.035, $logoSize, $logoSize);
            } catch (Throwable) {
            }
        }

        $pdf->SetTextColor(255, 255, 255);
        $pdf->SetFont('Helvetica', 'B', 8.5);
        $pdf->SetXY($x + 0.06, $y + 0.035 + $logoSize + 0.01);
        $pdf->Cell($w - 0.12, 0.1, $schoolNamePdf, 0, 0, 'C');

        if ($mottoPdf !== '') {
            $pdf->SetFont('Helvetica', 'B', 5.2);
            $pdf->SetXY($x + 0.06, $y + $headerH - 0.12);
            $pdf->Cell($w - 0.12, 0.08, $mottoPdf, 0, 0, 'C');
        }

        $bodyTop = $y + $headerH + 0.06;
        $pdf->SetTextColor(11, 47, 115);
        $pdf->SetFont('Helvetica', 'B', 9.5);
        $pdf->SetXY($x + 0.07, $bodyTop);
        $pdf->Cell($w - 0.14, 0.11, strtoupper($fullName), 0, 1, 'C');

        $pdf->SetTextColor(27, 86, 177);
        $pdf->SetFont('Helvetica', 'B', 6);
        $pdf->SetX($x + 0.07);
        $pdf->Cell($w - 0.14, 0.07, strtoupper($rolePdf), 0, 1, 'C');

        $ruleY = $bodyTop + 0.22;
        $pdf->SetDrawColor(215, 222, 234);
        $pdf->Line($x + 0.08, $ruleY, $x + $w - 0.08, $ruleY);

        $infoLeft = $x + 0.08;
        $infoW = $w * 0.52;
        $labelY = $ruleY + 0.05;

        $gradeLabel = $kind === 'staff' ? 'CLASS / ASSIGNMENT' : 'GRADE';

        $pdf->SetTextColor(51, 51, 51);
        $pdf->SetFont('Helvetica', 'B', 5);
        $pdf->SetXY($infoLeft, $labelY);
        $pdf->Cell($infoW, 0.05, $gradeLabel, 0, 1, 'L');

        $pdf->SetTextColor($blueLight[0], $blueLight[1], $blueLight[2]);
        $pdf->SetFont('Helvetica', 'B', 7.5);
        $pdf->SetX($infoLeft);
        $pdf->Cell($infoW, 0.08, $grade, 0, 1, 'L');

        $pdf->SetTextColor(51, 51, 51);
        $pdf->SetFont('Helvetica', 'B', 5);
        $pdf->SetX($infoLeft);
        $pdf->Cell($infoW, 0.05, 'ACADEMIC YEAR', 0, 1, 'L');

        $pdf->SetTextColor($blueLight[0], $blueLight[1], $blueLight[2]);
        $pdf->SetFont('Helvetica', 'B', 7.5);
        $pdf->SetX($infoLeft);
        $pdf->Cell($infoW, 0.08, $year, 0, 1, 'L');

        $pdf->SetTextColor(51, 51, 51);
        $pdf->SetFont('Helvetica', 'B', 5);
        $pdf->SetX($infoLeft);
        $pdf->Cell($infoW, 0.05, $idLabel, 0, 1, 'L');

        $pdf->SetTextColor($blueLight[0], $blueLight[1], $blueLight[2]);
        $pdf->SetFont('Helvetica', 'B', 7.5);
        $pdf->SetX($infoLeft);
        $pdf->MultiCell($infoW, 0.09, $schoolId, 0, 'L');

        $qrSize = 0.38;
        $qrX = $x + $w - 0.08 - $qrSize;
        $qrY = $ruleY + 0.04;

        if ($qrPath !== '' && is_file($qrPath)) {
            try {
                $pdf->SetDrawColor($blueLight[0], $blueLight[1], $blueLight[2]);
                $pdf->Rect($qrX - 0.03, $qrY - 0.03, $qrSize + 0.06, $qrSize + 0.06);
                $pdf->Image($qrPath, $qrX, $qrY, $qrSize, $qrSize, 'PNG');
            } catch (Throwable) {
            }
        }

        $pdf->SetTextColor($blueLight[0], $blueLight[1], $blueLight[2]);
        $pdf->SetFont('Helvetica', 'B', 4.5);
        $pdf->SetXY($qrX - 0.05, $qrY + $qrSize + 0.02);
        $pdf->Cell($qrSize + 0.1, 0.05, 'SCAN TO VERIFY', 0, 0, 'C');

        $fy = $y + $h - $footerH;
        $pdf->SetFillColor($blue[0], $blue[1], $blue[2]);
        $pdf->Rect($x, $fy, $w, $footerH, 'F');

        $smallLogo = 0.1;
        if ($logoPath !== null && is_readable($logoPath)) {
            try {
                $pdf->Image($logoPath, $x + $w / 2 - $smallLogo / 2, $fy + 0.03, $smallLogo, $smallLogo);
            } catch (Throwable) {
            }
        }

        $pdf->SetTextColor(255, 255, 255);
        $pdf->SetFont('Helvetica', 'B', 4.5);
        $lines = preg_split('/\r\n|\r|\n/', $footerBlock) ?: [$footerBlock];
        $lineY = $fy + 0.03 + $smallLogo + 0.015;
        foreach ($lines as $line) {
            $line = trim($line);
            if ($line === '') {
                continue;
            }

            $pdf->SetXY($x + 0.04, $lineY);
            $pdf->Cell($w - 0.08, 0.055, $this->formatter->toPdf($line), 0, 1, 'C');
            $lineY += 0.055;
        }
    }

    protected function renderQrPng(string $payload): string
    {
        $qrOptions = new QROptions([
            'version' => 5,
            'outputInterface' => QRGdImagePNG::class,
            'outputBase64' => false,
            'eccLevel' => QRCode::ECC_M,
            'scale' => 4,
        ]);

        $qr = new QRCode($qrOptions);

        return $qr->render($payload);
    }

    protected function logoFilePath(): ?string
    {
        return $this->formatter->firstExisting([
            public_path('assets/images/school_logo.png'),
            public_path('assets/images/logo.png'),
        ]);
    }

    protected function footerBlock(string $schoolName): string
    {
        $address = trim((string) config('badges.footer_address', ''));
        if ($address !== '') {
            return $schoolName . "\n" . $address;
        }

        return $schoolName;
    }
}