<?php
session_start();
if (!isset($_SESSION["user_id"])) {
    header("Location: ../login.php");
    exit;
}

if (!isset($_GET['id'])) {
    die("Invoice ID required.");
}

require_once __DIR__ . '/../db/config.php';
$db = db();

// Fetch invoice and ensure it belongs to the user
$stmt = $db->prepare("SELECT i.*, u.name as user_name, u.email as user_email 
                       FROM invoices i 
                       JOIN users u ON i.user_id = u.id 
                       WHERE i.id = ? AND i.user_id = ?");
$stmt->execute([$_GET['id'], $_SESSION['user_id']]);
$invoice = $stmt->fetch();

if (!$invoice) {
    die("Invoice not found.");
}

require_once __DIR__ . '/../fpdf/fpdf.php';

class InvoicePDF extends FPDF {
    function Header() {
        $project_name = $_SERVER['PROJECT_NAME'] ?? 'LPA Online';
        $this->SetFont('Arial', 'B', 15);
        $this->Cell(80);
        $this->Cell(30, 10, strtoupper($project_name), 0, 0, 'C');
        $this->Ln(20);
    }

    function Footer() {
        $this->SetY(-15);
        $this->SetFont('Arial', 'I', 8);
        $this->Cell(0, 10, 'Page ' . $this->PageNo() . '/{nb}', 0, 0, 'C');
    }
}

$pdf = new InvoicePDF();
$pdf->AliasNbPages();
$pdf->AddPage();
$pdf->SetFont('Arial', 'B', 16);
$pdf->Cell(0, 10, 'INVOICE', 0, 1, 'L');
$pdf->SetFont('Arial', '', 10);
$pdf->Cell(0, 10, 'Invoice Number: #' . $invoice['invoice_number'], 0, 1, 'L');
$pdf->Cell(0, 10, 'Date: ' . date('M d, Y', strtotime($invoice['created_at'])), 0, 1, 'L');
$pdf->Ln(5);

$pdf->SetFont('Arial', 'B', 12);
$pdf->Cell(0, 10, 'Billed To:', 0, 1, 'L');
$pdf->SetFont('Arial', '', 10);
$pdf->Cell(0, 10, ($invoice['user_name'] ?: 'N/A'), 0, 1, 'L');
$pdf->Cell(0, 10, $invoice['user_email'], 0, 1, 'L');
$pdf->Ln(10);

// Table Header
$pdf->SetFillColor(240, 240, 240);
$pdf->SetFont('Arial', 'B', 10);
$pdf->Cell(130, 10, 'Description', 1, 0, 'L', true);
$pdf->Cell(60, 10, 'Amount', 1, 1, 'R', true);

// Table Body
$pdf->SetFont('Arial', '', 10);
$items = json_decode($invoice['items_json'] ?? '[]', true);
if (empty($items)) {
    $pdf->Cell(130, 10, $invoice['credits_added'] . ' LPA Credits', 1, 0, 'L');
    $pdf->Cell(60, 10, ($invoice['currency'] === 'GBP' ? '£' : $invoice['currency']) . number_format($invoice['amount'], 2), 1, 1, 'R');
} else {
    foreach ($items as $item) {
        $pdf->Cell(130, 10, $item['name'], 1, 0, 'L');
        $pdf->Cell(60, 10, ($invoice['currency'] === 'GBP' ? '£' : $invoice['currency']) . number_format($item['amount'], 2), 1, 1, 'R');
    }
}

// Total
$pdf->SetFont('Arial', 'B', 10);
$pdf->Cell(130, 10, 'Total Paid', 1, 0, 'R');
$pdf->Cell(60, 10, ($invoice['currency'] === 'GBP' ? '£' : $invoice['currency']) . number_format($invoice['amount'], 2), 1, 1, 'R');

$pdf->Ln(20);
$pdf->SetFont('Arial', 'I', 10);
$pdf->Cell(0, 10, 'Thank you for your business.', 0, 1, 'C');

$pdf->Output('I', 'Invoice-' . $invoice['invoice_number'] . '.pdf');