<?php

namespace App\Observers;

use App\Models\ActivityGpc;
use App\Models\ReferenceGwp;

class ActivityGpcObserver
{
    public function saving(ActivityGpc $gpc)
    {
        $gwp = $this->getGWPValues();

        $co2eq =
            ($gpc->co2 ? $gpc->co2 * $gwp['CO2']->value : 0) +
            ($gpc->ch4 ? $gpc->ch4 * $gwp['CH4']->value : 0) +
            ($gpc->n2o ? $gpc->n2o * $gwp['N2O']->value : 0);

        $gpc->gwp_co2 = $gwp['CO2']->value;
        $gpc->gwp_ch4 = $gwp['CH4']->value;
        $gpc->gwp_n2o = $gwp['N2O']->value;
        $gpc->co2eq = $co2eq;
    }

    protected function getGWPValues()
    {
        $gwp = ReferenceGwp::whereHas('ar', function ($query) {
            $query->isActive();
        })->get();

        return $gwp->keyBy('ghg_code');
    }
}