<?php

namespace App\Services;

use App\Models\Vat;
use App\Models\VatTransaction;

class PurchaseVatTransaction
{
    /**
     * Store VAT transactions for a purchase detail.
     */
    public static function storeVatTransactions($business, $detail, $product, $party = null)
    {
        $vatAmountTotal = 0;

        if ($product->vat_id) {
            $vat = Vat::find($product->vat_id);
            if ($vat) {
                $vatRate = $vat->rate;
                $qty = $detail->quantities;
                $purchasePrice = $detail->productPurchasePrice;

                // For purchases, it's often inclusive in the purchase price provided by supplier
                // or on top. We'll follow the standard logic.
                if ($product->vat_type === 'inclusive') {
                    $vatAmount = ($purchasePrice * $vatRate) / (100 + $vatRate);
                } else {
                    $vatAmount = ($purchasePrice * $vatRate) / 100;
                }

                $vatAmountTotal = $vatAmount * $qty;

                VatTransaction::create([
                    'business_id' => $business->id,
                    'vat_id' => $vat->id,
                    'vat_rate' => $vatRate,
                    'vat_amount' => $vatAmountTotal,
                    'vatable_id' => $detail->id,
                    'vatable_type' => get_class($detail),
                ]);
            }
        }

        return $vatAmountTotal;
    }

    /**
     * Adjust VAT on purchase return.
     */
    public static function productReturnVatCalculation($detail, $requested_qty, $returnDetail, $totalQty)
    {
        $vatTransaction = VatTransaction::where('vatable_id', $detail->id)
            ->where('vatable_type', get_class($detail))
            ->first();

        if ($vatTransaction) {
            $returnVatAmount = ($vatTransaction->vat_amount / $totalQty) * $requested_qty;

            VatTransaction::create([
                'business_id' => $vatTransaction->business_id,
                'vat_id' => $vatTransaction->vat_id,
                'vat_rate' => $vatTransaction->vat_rate,
                'vat_amount' => -$returnVatAmount,
                'vatable_id' => $returnDetail->id,
                'vatable_type' => get_class($returnDetail),
            ]);
        }
    }
}