Kent-logistics-Laravel/app/Http/Controllers/Admin/AdminInvoiceController.php

<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use App\Models\Invoice;
use App\Models\InvoiceItem;
use Mpdf\Mpdf;

class AdminInvoiceController extends Controller
{
    // -------------------------------------------------------------
    // INVOICE LIST PAGE
    // -------------------------------------------------------------
    public function index()
    {
        $invoices = Invoice::latest()->get();
        return view('admin.invoice', compact('invoices'));
    }

    // -------------------------------------------------------------
    // POPUP VIEW (AJAX)
    // -------------------------------------------------------------
    public function popup($id)
    {
        $invoice = Invoice::with('items')->findOrFail($id);
        return view('admin.popup_invoice', compact('invoice'));
    }

    // -------------------------------------------------------------
    // EDIT INVOICE PAGE
    // -------------------------------------------------------------
    public function edit($id)
    {
        $invoice = Invoice::findOrFail($id);
        return view('admin.invoice_edit', compact('invoice'));
    }

    // -------------------------------------------------------------
    // UPDATE INVOICE
    // -------------------------------------------------------------
    public function update(Request $request, $id)
    {
        $invoice = Invoice::findOrFail($id);

        // Validate editable fields
        $data = $request->validate([
            'invoice_date'      => 'required|date',
            'due_date'          => 'required|date|after_or_equal:invoice_date',
            'payment_method'    => 'nullable|string',
            'reference_no'      => 'nullable|string|max:255',
            'final_amount'      => 'required|numeric|min:0',
            'gst_percent'       => 'required|numeric|min:0|max:28',
            'status'            => 'required|in:pending,paid,overdue',
            'notes'             => 'nullable|string',
        ]);

        // Auto-calc
        $gst_amount = ($data['final_amount'] * $data['gst_percent']) / 100;
        $final_amount_with_gst = $data['final_amount'] + $gst_amount;

        $data['gst_amount'] = $gst_amount;
        $data['final_amount_with_gst'] = $final_amount_with_gst;

        // Update DB
        $invoice->update($data);

        // Generate PDF
        $this->generateInvoicePDF($invoice);

        return redirect()
            ->route('admin.invoices.index')
            ->with('success', 'Invoice updated & PDF generated successfully.');
    }

    // -------------------------------------------------------------
    // PDF GENERATION USING mPDF
    // -------------------------------------------------------------
    public function generateInvoicePDF($invoice)
    {
        // PDF Name
        $fileName = 'invoice-' . $invoice->invoice_number . '.pdf';

        // Save directly in /public/invoices
        $folder = public_path('invoices/');

        // Create folder if not exists
        if (!file_exists($folder)) {
            mkdir($folder, 0777, true);
        }

        // Full path
        $filePath = $folder . $fileName;

        // Delete old file
        if (file_exists($filePath)) {
            unlink($filePath);
        }

        // Initialize mPDF
        $mpdf = new Mpdf([
            'mode' => 'utf-8',
            'format' => 'A4',
            'default_font' => 'sans-serif'
        ]);

        // Load HTML view
        $html = view('admin.pdf.invoice', compact('invoice'))->render();

        // Generate
        $mpdf->WriteHTML($html);

        // Save to public/invoices
        $mpdf->Output($filePath, 'F');

        // Save path in DB
        $invoice->update([
            'pdf_path' => 'invoices/' . $fileName
        ]);
    }
}