<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Booking extends Model
{
    /**************************************************************************
     * DIRECT RELATIONS                                                       *
     **************************************************************************/

    /**
     * Return all sub-bookings which belong to the booking.
     *
     * @return Illuminate\Database\Eloquent\Relations\HasMany
     */
    public function subBookings()
    {
        return $this->hasMany('App\SubBooking');
    }

    /**************************************************************************
     * INDIRECT RELATIONS                                                     *
     **************************************************************************/

    /**
     * Get the project to which the booking belongs. If the booking consists of
     * more than one sub-booking, null is returned.
     *
     * @return App\Project
     */
    public function project()
    {
        if ($this->isSimple()) {
            return $this->subBookings->first()->project;
        }

        return null;
    }

    /**
     * Get the account type of the booking. If the booking consists of more than
     * one sub-booking, null is returned.
     *
     * @return App\AccountType
     */
    public function accountType()
    {
        if ($this->isSimple()) {
            return $this->subBookings->first()->accountType;
        }

        return null;
    }

    /**************************************************************************
     * INDIRECT PROPERTIES                                                    *
     **************************************************************************/

    /**
     * Get the (unsigned) amount of all sub-bookings.
     *
     * @return float
     */
    public function amount()
    {
        return $this->subBookings->sum('amount');
    }

    /**
     * Return the sum of all signed amounts of all sub-bookings related to the
     * booking.
     *
     * @return float
     */
    public function signedAmount()
    {
        $sum = 0;

        foreach ($this->subBookings as $subBooking) {
          $sum += $subBooking->signedAmount();
        }

        return $sum;
    }

    /**
     * Return true, if the booking consists only of one sub-booking.
     *
     * @return boolean
     */
    public function isSimple()
    {
        return $this->subBookings->count() === 1;
    }
}