<?php

class ReceiptGenerator
{
    private $fontPath;
    private $logoPath;

    public function __construct()
    {
        if (!extension_loaded('gd')) {
            throw new Exception("The PHP GD extension is not enabled. Please enable it in your php.ini or install php-gd.");
        }

        // Try to find a suitable font
        $fonts = [
            'C:/Windows/Fonts/arial.ttf',
            '/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf',
            '/usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf',
            '/usr/share/fonts/TTF/arial.ttf'
        ];

        $this->fontPath = null;
        foreach ($fonts as $font) {
            if (file_exists($font)) {
                $this->fontPath = $font;
                break;
            }
        }

        $this->logoPath = __DIR__ . '/../assets/logo.png';
    }

    public function generate($data)
    {
        $width = 900; // Increased width to accommodate 6 columns comfortably
        // Calculate dynamic height
        $baseHeight = 450;
        $rowHeight = 40;
        $numRows = count($data['allocations'] ?? []);
        $height = $baseHeight + ($numRows * $rowHeight) + 150;

        $image = imagecreatetruecolor($width, $height);

        // Colors
        $white = imagecolorallocate($image, 255, 255, 255);
        $black = imagecolorallocate($image, 0, 0, 0);
        $grey = imagecolorallocate($image, 100, 100, 100);
        $lightGrey = imagecolorallocate($image, 240, 240, 240);

        imagefilledrectangle($image, 0, 0, $width, $height, $white);

        // Logo
        if (file_exists($this->logoPath)) {
            $logo = @imagecreatefrompng($this->logoPath);
            if ($logo) {
                $logoW = imagesx($logo);
                $logoH = imagesy($logo);
                $targetW = 100;
                $targetH = ($targetW / $logoW) * $logoH;

                imagecopyresampled($image, $logo, 40, 30, 0, 0, (int) $targetW, (int) $targetH, (int) $logoW, (int) $logoH);
            }
        }

        // School Name Logic
        $schoolName = "ACE JUNIOR COLLEGE";
        $levelName = isset($data['level_name']) ? strtoupper($data['level_name']) : '';
        // Check for Senior classes (SSS 1, SSS 2, SSS 3, or Senior)
        if (strpos($levelName, 'SSS') !== false || strpos($levelName, 'SENIOR') !== false) {
            $schoolName = "ACE SENIOR COLLEGE";
        }

        // Header
        $this->centerText($image, 18, 50, $schoolName, $black);
        $this->centerText($image, 10, 75, "...education for excellence", $grey);
        $this->centerText($image, 10, 100, "1, Ebute - Igbogbo Road, Ipakodo, Ikorodu, Lagos, Nigeria", $black);
        $this->centerText($image, 10, 120, "Phone No(s): 08027449739, 08077275777", $black);
        $this->centerText($image, 10, 140, "mailto:info@acecollege.com.ng https://www.acecollege.com.ng", $black);

        // Receipt Title
        $titleY = 180;
        $receiptNo = $data['receipt_no'] ?? 'N/A';
        $this->centerText($image, 12, $titleY, "SCHOOL FEES RECEIPT - REFERENCE NO: $receiptNo", $black);

        // Session Info
        $session = $data['allocations'][0]['academic_session'] ?? '----';
        $term = $data['allocations'][0]['term_of_session'] ?? '-';
        $nextSession = is_numeric($session) ? ($session + 1) : '';
        $levelPart = isset($data['level_name']) ? ' - ' . strtoupper($data['level_name']) : '';
        $sessionStr = "$session/$nextSession ACADEMIC SESSION, TERM $term" . $levelPart;
        $this->centerText($image, 10, $titleY + 25, $sessionStr, $grey);

        // Student Box
        $boxY = 230;
        imagerectangle($image, 40, $boxY, $width - 40, $boxY + 40, $grey);
        // We expect student_name to be passed in $data. If not, fallback.
        $studentName = isset($data['student_name']) ? strtoupper($data['student_name']) : (isset($data['student_code']) ? "STUDENT CODE: " . $data['student_code'] : 'UNKNOWN STUDENT');
        $this->centerText($image, 14, $boxY + 26, $studentName, $grey);

        // Table Header
        $tableY = 300;
        // 6 Columns: Description, Term/Session, Amount Billed, Amount Paid, Paid To Date, To Balance
        // Width 900. Margins 40. Active 820.
        // Approx X: 40, 320, 440, 560, 680, 800 (Right Boundary for last col is width-40 = 860)
        // Let's adjust spacing.
        $cols = [40, 300, 440, 550, 660, 780];

        imageline($image, 40, $tableY, $width - 40, $tableY, $black);
        imageline($image, 40, $tableY + 30, $width - 40, $tableY + 30, $black);

        if ($this->fontPath) {
            imagettftext($image, 8, 0, $cols[0], $tableY + 20, $black, $this->fontPath, "FEE DESCRIPTION");
            imagettftext($image, 8, 0, $cols[1], $tableY + 20, $black, $this->fontPath, "TERM/SESSION");
            imagettftext($image, 8, 0, $cols[2], $tableY + 20, $black, $this->fontPath, "AMOUNT BILLED");
            imagettftext($image, 8, 0, $cols[3], $tableY + 20, $black, $this->fontPath, "AMOUNT PAID");
            imagettftext($image, 8, 0, $cols[4], $tableY + 20, $black, $this->fontPath, "PAID TO DATE");
            imagettftext($image, 8, 0, $cols[5], $tableY + 20, $black, $this->fontPath, "TO BALANCE");
        } else {
            // Fallback font 
            imagestring($image, 3, $cols[0], $tableY + 5, "FEE DESCRIPTION", $black);
            imagestring($image, 3, $cols[1], $tableY + 5, "TERM/SESSION", $black);
            imagestring($image, 3, $cols[2], $tableY + 5, "BILLED", $black);
            imagestring($image, 3, $cols[3], $tableY + 5, "PAID", $black);
            imagestring($image, 3, $cols[4], $tableY + 5, "PAID TO DATE", $black);
            imagestring($image, 3, $cols[5], $tableY + 5, "TO BALANCE", $black);
        }

        // Rows
        $currY = $tableY + 30;
        $totalBilled = 0;
        $totalPaidToDate = 0;
        $totalBalance = 0;
        // Total Paid is passed from outside
        $totalAmountPaid = 0;

        if (isset($data['allocations']) && is_array($data['allocations'])) {
            foreach ($data['allocations'] as $alloc) {
                $desc = $alloc['description'];
                $session = $alloc['academic_session'] ?? '';
                $term = $alloc['term_of_session'] ?? '';

                // Format: Term/Session e.g. "1/2025" or "1st/2025"
                // Assuming simpler "1/2025" format for space
                $termSessionStr = "$term/$session";

                $billedVal = $alloc['amount_billed'] ?? 0;
                $paidVal = $alloc['amount'] ?? 0;
                $paidToDateVal = $alloc['total_paid_to_date'] ?? 0;
                $balanceVal = $alloc['balance'] ?? 0;

                $totalBilled += $billedVal;
                $totalAmountPaid += $paidVal;
                $totalPaidToDate += $paidToDateVal;
                $totalBalance += $balanceVal;

                $billed = number_format($billedVal, 2);
                $paid = number_format($paidVal, 2);
                $paidToDate = number_format($paidToDateVal, 2);
                $balance = number_format($balanceVal, 2);

                $currY += 30;

                if ($this->fontPath) {
                    imagettftext($image, 8, 0, $cols[0], $currY, $black, $this->fontPath, substr($desc, 0, 35));
                    imagettftext($image, 8, 0, $cols[1], $currY, $black, $this->fontPath, $termSessionStr); // Term/Session
                } else {
                    imagestring($image, 3, $cols[0], $currY - 10, substr($desc, 0, 35), $black);
                    imagestring($image, 3, $cols[1], $currY - 10, $termSessionStr, $black);
                }

                // Right Alignment using approx right boundaries
                // Col 2 (Billed): starts 440. Right align around 530?
                // Col 3 (Paid): starts 550.
                // Col 4 (PTD): starts 660.
                // Col 5 (Bal): starts 780.

                $rbBilled = 530;
                $rbPaid = 640;
                $rbPTD = 760;
                $rbBal = $width - 40;

                $this->rightAlignText($image, 8, $rbBilled, $currY, $billed, $black);
                $this->rightAlignText($image, 8, $rbPaid, $currY, $paid, $black);
                $this->rightAlignText($image, 8, $rbPTD, $currY, $paidToDate, $black);
                $this->rightAlignText($image, 8, $rbBal, $currY, $balance, $black);
            }
        }

        // Total Row
        $currY += 20;
        imageline($image, 40, $currY, $width - 40, $currY, $black);
        $currY += 26;

        $totalPaidStr = number_format($data['total_paid'] ?? 0, 2);
        $totalBilledStr = number_format($totalBilled, 2);
        $totalPaidToDateStr = number_format($totalPaidToDate, 2);
        $totalBalanceStr = number_format($totalBalance, 2);

        // Columns for totals
        $rbBilled = 530;
        $rbPaid = 640;
        $rbPTD = 760;
        $rbBal = $width - 40;

        $this->rightAlignText($image, 9, $rbBilled, $currY, $totalBilledStr, $grey);
        $this->rightAlignText($image, 9, $rbPaid, $currY, $totalPaidStr, $grey);
        $this->rightAlignText($image, 9, $rbPTD, $currY, $totalPaidToDateStr, $grey);
        $this->rightAlignText($image, 9, $rbBal, $currY, $totalBalanceStr, $grey);

        imageline($image, 40, $currY + 14, $width - 40, $currY + 14, $black);

        // Footer
        $footerY = $currY + 50;
        if ($this->fontPath) {
            imagettftext($image, 9, 0, 40, $footerY, $black, $this->fontPath, "RECEIPT DULY VERIFIED BY");
            imagettftext($image, 9, 0, 40, $footerY + 20, $black, $this->fontPath, "BURSAR'S OFFICE");
        } else {
            imagestring($image, 3, 40, $footerY - 10, "RECEIPT DULY VERIFIED BY", $black);
            imagestring($image, 3, 40, $footerY + 10, "BURSAR'S OFFICE", $black);
        }

        $receivedY = $footerY;
        $this->rightAlignText($image, 9, $width - 40, $receivedY, "RECEIVED IN", $black);
        $this->rightAlignText($image, 9, $width - 40, $receivedY + 15, "BANK", $black);

        $this->rightAlignText($image, 9, $width - 40, $receivedY + 40, "RECEIVED ON", $black);
        $dateStr = isset($data['payment_date']) ? strtoupper(date("F d, Y", strtotime($data['payment_date']))) : date("F d, Y");
        $this->rightAlignText($image, 9, $width - 40, $receivedY + 55, $dateStr, $black);

        ob_start();
        imagepng($image);
        $content = ob_get_clean();
        imagedestroy($image);

        return $content;
    }

    public function generateBase64($data)
    {
        $content = $this->generate($data);
        return base64_encode($content);
    }

    private function centerText($image, $size, $y, $text, $color)
    {
        if ($this->fontPath) {
            try {
                $box = imagettfbbox($size, 0, $this->fontPath, $text);
                $textW = $box[2] - $box[0];
                $x = (int) ((imagesx($image) - $textW) / 2);
                imagettftext($image, $size, 0, $x, (int) $y, $color, $this->fontPath, $text);
                return;
            } catch (Exception $e) {
                // Fallthrough to built-in font
            }
        }
        // Fallback or if fontPath is missing
        $gdSize = (int) min(5, max(1, floor($size / 3)));
        $charWidth = imagefontwidth($gdSize);
        $textW = strlen($text) * $charWidth;
        $x = (int) ((imagesx($image) - $textW) / 2);
        imagestring($image, $gdSize, $x, (int) $y, $text, $color);
    }

    private function rightAlignText($image, $size, $rightX, $y, $text, $color)
    {
        if ($this->fontPath) {
            try {
                $box = imagettfbbox($size, 0, $this->fontPath, $text);
                $textW = $box[2] - $box[0];
                $x = (int) ($rightX - $textW);
                imagettftext($image, $size, 0, $x, (int) $y, $color, $this->fontPath, $text);
                return;
            } catch (Exception $e) {
                // Fallthrough
            }
        }
        $gdSize = (int) min(5, max(1, floor($size / 3)));
        $charWidth = imagefontwidth($gdSize);
        $x = (int) ($rightX - (strlen($text) * $charWidth));
        imagestring($image, $gdSize, $x, (int) $y, $text, $color);
    }
}