<?php

namespace App\Controllers\View;

use App\Controllers\BaseController;
use App\Models\ClassSectionModel;
use App\Models\ConfigurationModel;

class CertificateController extends BaseController
{
    protected $classSectionModel;
    protected $configModel;
    protected $schoolYear;

    public function __construct()
    {
        $this->classSectionModel = new ClassSectionModel();
        $this->configModel       = new ConfigurationModel();
        $this->schoolYear        = $this->configModel->getConfig('school_year');
    }

    public function index()
    {
        $db             = \Config\Database::connect();
        $classSectionId = $this->request->getGet('class_section_id');
        $schoolYear     = $this->request->getGet('school_year') ?? $this->schoolYear;

        $classSections = $db->table('classSection cs')
            ->select('cs.class_section_id, cs.class_section_name')
            ->join('student_class sc', 'sc.class_section_id = cs.class_section_id')
            ->join('students s', 's.id = sc.student_id')
            ->where('s.is_active', 1)
            ->where('sc.school_year', $schoolYear)
            ->groupBy('cs.class_section_id, cs.class_section_name')
            ->having('COUNT(s.id) >', 1)
            ->orderBy('cs.class_section_name', 'ASC')
            ->get()->getResultArray();

        $students = [];
        if ($classSectionId) {
            $students = $db->table('student_class sc')
                ->select('s.id, s.firstname, s.lastname, cs.class_section_name AS grade')
                ->join('students s', 's.id = sc.student_id')
                ->join('classSection cs', 'cs.class_section_id = sc.class_section_id')
                ->where('sc.class_section_id', (int) $classSectionId)
                ->where('s.is_active', 1)
                ->where('sc.school_year', $schoolYear)
                ->orderBy('s.lastname', 'ASC')
                ->orderBy('s.firstname', 'ASC')
                ->get()->getResultArray();
        }

        return view('admin/certificates/index', [
            'classSections'   => $classSections,
            'students'        => $students,
            'selectedClassId' => $classSectionId,
            'schoolYear'      => $schoolYear,
            'certDate'        => date('m/d/Y'),
        ]);
    }

    public function generate()
    {
        $studentIds     = $this->request->getPost('student_ids') ?? [];
        $certDate       = trim($this->request->getPost('cert_date') ?? date('m/d/Y'));
        $classSectionId = $this->request->getPost('class_section_id');

        if (empty($studentIds)) {
            return redirect()->to('administrator/certificates')->with('error', 'Please select at least one student.');
        }

        // Sanitize inputs
        $studentIds = array_filter(array_map('intval', $studentIds));
        $certDate   = preg_replace('/[^0-9\/\-]/', '', $certDate);

        if (empty($studentIds)) {
            return redirect()->to('administrator/certificates')->with('error', 'Invalid student selection.');
        }

        $db       = \Config\Database::connect();
        $students = [];

        foreach ($studentIds as $id) {
            if ($classSectionId) {
                $row = $db->table('student_class sc')
                    ->select('s.id, s.firstname, s.lastname, cs.class_section_name AS grade')
                    ->join('students s', 's.id = sc.student_id')
                    ->join('classSection cs', 'cs.class_section_id = sc.class_section_id')
                    ->where('sc.class_section_id', (int) $classSectionId)
                    ->where('s.id', $id)
                    ->get()->getRowArray();
            } else {
                $row = null;
            }

            if (!$row) {
                $s = $db->table('students')
                    ->select('id, firstname, lastname, registration_grade AS grade')
                    ->where('id', $id)
                    ->get()->getRowArray();
                $row = $s ?: null;
            }

            if ($row) {
                $students[] = $row;
            }
        }

        if (empty($students)) {
            return redirect()->to('administrator/certificates')->with('error', 'No valid students found.');
        }

        $pdfData = $this->buildPdf($students, $certDate);
        $filename = 'Certificates_' . date('Ymd_His') . '.pdf';

        return $this->response
            ->setHeader('Content-Type', 'application/pdf')
            ->setHeader('Content-Disposition', 'inline; filename="' . $filename . '"')
            ->setBody($pdfData);
    }

    // ─── PDF generation ────────────────────────────────────────────────────────

    private function buildPdf(array $students, string $certDate): string
    {
        $fontDir = FCPATH . 'assets' . DIRECTORY_SEPARATOR . 'certificates' . DIRECTORY_SEPARATOR . 'fonts' . DIRECTORY_SEPARATOR;
        $imgDir  = FCPATH . 'assets' . DIRECTORY_SEPARATOR . 'certificates' . DIRECTORY_SEPARATOR . 'images' . DIRECTORY_SEPARATOR;

        // Convert TTF → TCPDF format on first run (cached in TCPDF's own fonts dir).
        // K_PATH_FONTS must stay pointing at the TCPDF vendor fonts directory so that
        // built-in fonts (helvetica, times, …) remain findable by SetFont().
        $edwardianFont = \TCPDF_FONTS::addTTFfont($fontDir . 'Edwardian Script ITC Regular.ttf', 'TrueTypeUnicode', '', 32);
        $garamondBold  = \TCPDF_FONTS::addTTFfont($fontDir . 'Garamond Bold.ttf',                'TrueTypeUnicode', '', 32);
        $ebGaramond    = \TCPDF_FONTS::addTTFfont($fontDir . 'EBGaramond-Regular.ttf',           'TrueTypeUnicode', '', 32);

        // A4 landscape in points: 841.89 × 595.28
        $pdf = new \TCPDF('L', 'pt', 'A4', true, 'UTF-8', false);
        $pdf->SetCreator('Al Rahma Sunday School');
        $pdf->SetTitle('Student Certificates');
        $pdf->SetMargins(0, 0, 0, true);
        $pdf->SetAutoPageBreak(false, 0);
        $pdf->setPrintHeader(false);
        $pdf->setPrintFooter(false);
        $pdf->SetHeaderMargin(0);
        $pdf->SetFooterMargin(0);

        $W = $pdf->getPageWidth();   // 841.89 pt
        $H = $pdf->getPageHeight();  // 595.28 pt

        foreach ($students as $student) {
            $pdf->AddPage();
            $name  = $student['firstname'] . ' ' . $student['lastname'];
            $grade = $this->formatGrade($student['grade'] ?? '');
            $this->drawCertificate($pdf, $W, $H, $name, $grade, $certDate, $imgDir, $edwardianFont, $garamondBold, $ebGaramond);
        }

        return $pdf->Output('', 'S');
    }

    private function formatGrade(string $raw): string
    {
        $clean = trim($raw);
        $lower = strtolower($clean);

        // Numeric grades 1-9 → "Grade N"
        if (preg_match('/^\d+$/', $clean) && (int)$clean >= 1 && (int)$clean <= 9) {
            return 'Grade ' . $clean;
        }

        // Youth variants
        if ($lower === 'youth') {
            return 'Youth';
        }

        // KG → Kindergarten
        if ($lower === 'kg') {
            return 'Kindergarten';
        }

        return $clean;
    }

    /**
     * Draws one certificate page. Coordinate mapping from the original C# iTextSharp code:
     *   iTextSharp uses (x, y) with origin at bottom-left, y increases upward.
     *   TCPDF uses (x, y) with origin at top-left, y increases downward.
     *   Conversion: y_tcpdf = H - y_iTextSharp
     */
    private function drawCertificate(
        \TCPDF $pdf,
        float  $W,
        float  $H,
        string $name,
        string $grade,
        string $certDate,
        string $imgDir,
        string $edwardianFont,
        string $garamondBold,
        string $ebGaramond
    ): void {
        // ── Title image: iTS SetAbsolutePosition(126, 450), ScaleToFit(600, 300)
        // Bottom at y=450 from page bottom → top at H-450 ≈ 145. Place at top of page.
        $pdf->Image($imgDir . 'title.png', 126, 0, 600);

        // ── Background image: iTS position(280, 79), ScaleToFit(2500, 340)
        // background.png is 336×393 px → ScaleToFit gives ≈291×340 pt.
        // Top in TCPDF: H-79-340 = ~176
        $pdf->Image($imgDir . 'background.png', 280, 176, 291, 340);

        // ── Signature image: iTS position(140, 106), ScaleToFit(90, 90)
        // Top in TCPDF: H-106-90 = ~399
        $pdf->Image($imgDir . 'signature.png', 140, 399, 90, 90);

        // ── "Presented to:" — iTS ALIGN_CENTER baseline y=420 → TCPDF y≈155
        $pdf->SetFont('times', 'B', 24);
        $pdf->SetTextColor(0, 0, 0);
        $pdf->SetXY(0, 151);
        $pdf->Cell($W, 24, 'Presented to:', 0, 0, 'C');

        // ── Student name — iTS baseline y=334, 38 pt Edwardian Script → TCPDF y≈219
        // Bold effect: fill the glyph AND add a thin stroke around it (Edwardian has no bold variant).
        $pdf->SetFont($edwardianFont, '', 38);
        $pdf->SetDrawColor(0, 0, 0);
        $pdf->setTextRenderingMode(0.4, true, false);
        $pdf->SetXY(0, 219);
        $pdf->Cell($W, 38, $name, 0, 0, 'C');
        $pdf->setTextRenderingMode(0, true, false);

        // ── Line under name — iTS ALIGN_RIGHT at x=600, y=332 → TCPDF y≈243
        $pdf->SetFont('times', '', 20);
        $pdf->SetXY(0, 243);
        $pdf->Cell(600, 20, '___________________________________', 0, 0, 'R');

        // ── Description — iTS ALIGN_CENTER baseline y=302 → TCPDF y≈273
        $pdf->SetFont($ebGaramond, '', 20);
        $pdf->SetXY(0, 273);
        $pdf->Cell($W, 20, 'for successfully completing the requirements of', 0, 0, 'C');

        // ── Grade — iTS ALIGN_CENTER baseline y=265 → TCPDF y≈310
        $pdf->SetFont($garamondBold, '', 20);
        $pdf->SetXY(0, 310);
        $pdf->Cell($W, 20, $grade, 0, 0, 'C');

        // ── "at" — iTS ALIGN_CENTER baseline y=232 → TCPDF y≈343
        $pdf->SetFont('times', '', 20);
        $pdf->SetXY(0, 343);
        $pdf->Cell($W, 20, 'at', 0, 0, 'C');

        // ── School name — iTS ALIGN_CENTER baseline y=200 → TCPDF y≈375
        $pdf->SetFont($garamondBold, '', 20);
        $pdf->SetXY(0, 375);
        $pdf->Cell($W, 20, 'Al Rahma Sunday School', 0, 0, 'C');

        // ── Certificate date — iTS DrawGradientText at (598, 116), 26 pt Edwardian
        // TCPDF y ≈ H-116-26 = ~453
        $this->drawGradientText($pdf, $edwardianFont, 26, $certDate, 598, 453);

        // ── Date underline — iTS ALIGN_RIGHT at x=742, y=110 → TCPDF y≈465
        $pdf->SetFont('times', '', 20);
        $pdf->SetXY(0, 463);
        $pdf->Cell(742, 20, '_________________', 0, 0, 'R');

        // ── "Date" label — iTS at (690, 78) → TCPDF y≈497, x≈650
        $pdf->SetXY(650, 492);
        $pdf->Cell(80, 20, 'Date', 0, 0, 'C');

        // ── Signature underline — iTS ALIGN_LEFT at x=106, y=110 → TCPDF y≈465
        $pdf->SetXY(106, 463);
        $pdf->Cell(200, 20, '_________________', 0, 0, 'L');

        // ── "Signature" label — iTS at (190, 78) → TCPDF y≈497
        $pdf->SetXY(106, 492);
        $pdf->Cell(168, 20, 'Signature', 0, 0, 'C');
    }

    /**
     * Mimics the C# DrawGradientText — shadow passes give depth, final pass is solid black.
     */
    private function drawGradientText(\TCPDF $pdf, string $fontName, float $fontSize, string $text, float $x, float $y): void
    {
        $pdf->SetFont($fontName, '', $fontSize);

        // Shadow passes (progressively more opaque, slightly offset)
        for ($i = 0; $i < 6; $i++) {
            $alpha = ($i + 1) * 25 / 255; // 0.098 → 0.588
            $pdf->setAlpha($alpha);
            $pdf->SetTextColor(0, 0, 0);
            $pdf->Text($x + $i / 5, $y + $i / 5, $text);
        }

        // Main solid pass
        $pdf->setAlpha(1);
        $pdf->SetTextColor(0, 0, 0);
        $pdf->Text($x, $y, $text);
    }
}