exchange/app/Http/Controllers/InvoiceController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use Illuminate\Routing\ResponseFactory;
use Illuminate\Support\MessageBag;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Validator;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Model;
use App\Booking;
use App\Invoice;
use App\InvoiceDetails;
use App\InvoiceStatuses;

class InvoiceController extends Controller
{
    public function show($id)
    {
        // validate $id is number

        $invoice = Invoice::where('booking_id', $id)->first();
        if (!$invoice) {
            return response()->json(['message' => 'Invoice Not Found'], 404);
        }
        $lines = InvoiceDetails::where('invoice_id', $invoice['id'])->orderBy('order', 'asc')->get();

        $invoice->lines = $lines;
        return response()->json($invoice, 200);

    }

    public function create(Request $request, $id)
    {
        $user = $request->user();

        // validate $id

        $validatedData = $request->validate([
            'address' => 'required',
            'buyer_company' => 'required',
            'contact_no' => 'required',
            'marking' => 'required',
            'lines.*.order' => 'required|numeric',
            'lines.*.stock_code' => 'required',
            'lines.*.description' => 'required',
            'lines.*.quantity' => 'required|numeric',
            'lines.*.unit_price_rm' => 'required|numeric',
            'lines.*.unit_price_rmb' => '',
            'lines.*.total' => 'required|numeric',
        ]);
        
        // booking_id belongs to user
        $booking = Booking::where('id', $id)->first();
        if (!$booking) {
            return response()->json(['message' => 'Unable to find booking'], 403);
        }

        // user_id in booking does not match
        if ($booking->user_id !== $user->id) {
            return response()->json([
                'message' => 'Booking does not belongs to you'
            ], 403);
        }

        // Amount match with total
        $subtotalArray = array_map(
            function ($line) { return $line['total']; },
            $validatedData['lines']
        );
        $total = array_reduce($subtotalArray, function ($v1, $v2) {
            return $v1 + $v2;
        });
        if ($total !== $booking->amount) {
            return response()->json([
                'message' => 'Booking amount expected is '.$booking->amount.'. Your Invoice amount is $total.'
            ], 400);
        }

        // Write to database if does not exist
        $exist = Invoice::where('booking_id', $id)->first();
        if ($exist) {
            return response()
                    ->json(['message' => 'Invoice exist. Cannot create duplicate invoice. Try edit.'], 400);
        }

        // Generate PO Number - po20200810-001(PO Format)
        $dt = Carbon::now();
        $po_number = 'po'.$dt->format('Ymmdd').'-'.$id;

        $invoice = new Invoice;
        $invoice->amount = $total;
        $invoice->booking_id = (int)$id;
        $invoice->buyer_company = $validatedData['buyer_company'];
        $invoice->address = $validatedData['address'];
        $invoice->contact_no = $validatedData['contact_no'];
        $invoice->po_number = $po_number;
        $invoice->save();

        if (!$invoice) {
            return response()
                    ->json(['message' => 'Unable to Save Data'], 500);
        }

        // Insert invoice_id into lines
        foreach( $validatedData['lines'] as $key => $line) {
            $invoice_details = new InvoiceDetails;
            $invoice_details->order = $line['order'];
            $invoice_details->description = $line['description'];
            $invoice_details->quantity = $line['quantity'];
            $invoice_details->stock_code = $line['stock_code'];
            $invoice_details->invoice_id = $invoice->id;
            $invoice_details->unit_price_rmb = $line['unit_price_rmb'];
            $invoice_details->unit_price_rm = $line['unit_price_rm'];
            $invoice_details->total = $line['total'];

            $invoice_details->save();
        }
        unset($line);

        $invoice->lines = $invoice_details;


        if($invoice_details) {
            return $this->show($id);
        } else {
            return response(500);
        }
    }

    public function edit(Request $request, $id)
    {

    }

    public function updateStatus(Request $request, $id)
    {

    }

    public function getPO($id)
    {

    }

    public function getDO($id)
    {

    }

    public function getSupplierDO($id)
    {

    }
}