<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Facades\DB;
use Carbon\Carbon;

class SubBooking extends Model
{
    /**************************************************************************
     * DIRECT RELATIONS                                                       *
     **************************************************************************/
    
    /*
     * Get the booking which contains the sub-booking.
     *
     * @return Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function booking() {
        return $this->belongsTo('\App\Booking', 'booking_id');
    }
    
    /*
     * Get the person-target related to the sub-booking. 
     *
     * @return Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function personTarget()
    {
        return $this->belongsTo('App\PersonTarget', 'person_target_id');
    }

    /*
     * Get the project related to the sub-booking.
     *
     * @return Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function project()
    {
        return $this->belongsTo('App\Project', 'project_id');
    }
    
    /*
     * Get the account type related to the sub-booking. 
     *
     * @return Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function accountType() 
    {
        return $this->belongsTo('App\AccountType', 'account_type_id');
    }

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

    /*
     * Get the booking date for a sub-booking.
     *
     * @return string
     */
    public function date()
    {
        return $this->booking->date;
    }
    
    /*
     * Get the IO-type of the sub-booking.
     *
     * @return 
     */
    public function ioType()
    {
        return $this->accountType->accountClass->ioType;
    }

    
    public function signedAmount()
    {
        return $this->ioType()->factor * $this->amount;
    }

    public function personOrCompany()
    {
        return $this->booking->person_or_company;
    }

    /**************************************************************************
     * SUMS OVER INCOMES AND EXPEDITURES, ACCOUNT BALANCES                    *
     **************************************************************************/

    /**
     * Return the balance at a given date.
     * 
     * @param  string $date
     * @return float 
     */
    public static function balanceAt($date)
    {
        $date = Carbon::parse($date)->format('Y-m-d');

        $result = SubBooking::joinAccountBranch()
                            ->joinBookings()
                            ->where('bookings.date', '<=', $date)
                            ->selectRaw('sum(i_o_types.factor * sub_bookings.amount) as balance')
                            ->first()->balance;

        return is_null($result) ? 0.00 : $result;
    }

    /**
     * Return the sum of all expeditures in the given interval.
     *
     * Return the sum of all expeditures in the interval from $star to $end.
     * If $group is true, the result is grouped by year and month, such that the
     * collection contains for every month in the interval an model with the
     * properties 'year', 'month' and 'expeditures'.
     * Otherwise the result is a collection with a single model, containing the
     * property 'expeditures'.
     *
     * @param  string  $start
     * @param  string  $end
     * @param  string $group Toggle, if the result is grouped by year and month.
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function expedituresInInterval($start, $end, $group = false)
    {
        return SubBooking::cashFlowInInterval($start, $end, 'expeditures', $group);
    }
    
    /**
     * Return the sum of all expeditures in the given interval.
     *
     * Return the sum of all expeditures in the interval from $star to $end.
     * If $group is true, the result is grouped by year and month, such that the
     * collection contains for every month in the interval an model with the
     * properties 'year', 'month' and 'incomes'.
     * Otherwise the result is a collection with a single model, containing the
     * property 'incomes'.
     *
     * @param  string  $start
     * @param  string  $end
     * @param  string $group Toggle, if the result is grouped by year and month.
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function incomesInInterval($start, $end, $group = false)
    {
        return SubBooking::cashFlowInInterval($start, $end, 'incomes', $group);
    }

    /**
     * Since the incomesInInterval and expedituresInInterval methods are almost
     * the same, this is the collectively used code.
     *
     * @param  string $start
     * @param  string $end
     * @param  string $type  Can be 'incomes' or 'expeditures'
     * @param  string $group Toggle, if the result is grouped by year and month.
     * @return Illuminate\Database\Eloquent\collection
     */
    private static function cashFlowInInterval($start, $end, $type, $group = false)
    {
        $parsedStart = Carbon::parse($start);
        $parsedEnd = Carbon::parse($end);

        $typeName = ($type === 'incomes') ? 'Einnahme' : 'Ausgabe';

        $start = $parsedStart->format('Y-m-d');
        $end = $parsedEnd->format('Y-m-d');

        $result = SubBooking::joinAccountBranch()
                            ->interval($start, $end)
                            ->where('i_o_types.name', '=', $typeName)
                            ->selectRaw('sum(i_o_types.factor * sub_bookings.amount) as ' . $type);

        if ($group) {
            // Group the result, first by month, then by year
            $result = $result->groupBy('year', 'month')
                             ->selectRaw('sum(i_o_types.factor * sub_bookings.amount) as ' . $type . ',
                                YEAR(bookings.date) as year,
                                MONTH(bookings.date) as month')
                             ->get();

            // Add a model with values = 0 for those months without any
            // sub-booking. If we would not explicitly define a model for these
            // cases, we would try toget a property from a model that does not
            // exist. 
            $yearStart = $parsedStart->format('Y');
            $yearEnd = $parsedEnd->format('Y');

            for ($year = $yearStart; $year <= $yearEnd; $year++) {
                // Set the start and end month for a year, in case the given
                // interval starts or ends in the current year.
                $monthStart = ($year == $parsedStart->format('Y')) ?
                              $parsedStart->format('n') :
                              1;
                $monthEnd = ($year == $parsedEnd->format('Y')) ?
                             $parsedEnd->format('n') :
                             12;

                for ($month = $monthStart; $month <= $monthEnd; $month++) {
                    if ($result->where('year', '=', $year)
                               ->where('month', '=', $month)->isEmpty()) {
                        $subBooking = new SubBooking();

                        $subBooking->$type = 0;
                        $subBooking->year = (int) $year;
                        $subBooking->month = (int) $month;

                        $result->push($subBooking);
                    }
                }
            }

            return $result;
        }

        return $result->get();
    }

    /**************************************************************************
     * QUERY SCOPES                                                           *
     **************************************************************************/
    
    /**
     * Consider only sub-bookings in a given interval.
     *
     * @return Illuminate\Database\Eloquent\Builder
     */
    public function scopeInterval($query, $start, $end)
    {
        return $query->joinBookings()
                     ->where('bookings.date', '>=', Carbon::parse($start)->format('Y-m-d'))
                     ->where('bookings.date', '<=', Carbon::parse($end)->format('Y-m-d'));
    }

    /**
     * Join the 'bookings' table into the query.
     *
     * @return Illuminate\Database\Eloquent\Builder
     */
    public function scopeJoinBookings($query)
    {
        return $query->join('bookings', 'bookings.id', '=', 'sub_bookings.booking_id');
    }

    /**
     * Join the tables 'i_o_types', 'account_classes' and 'account_types' into
     * the query.
     *
     * @return Illuminate\Database\Eloquent\Builder
     */
    public function scopeJoinAccountBranch($query)
    {
        return $query->join('account_types', 'account_types.id', '=', 'sub_bookings.account_type_id')
                     ->join('account_classes', 'account_classes.id', '=', 'account_types.account_class_id')
                     ->join('i_o_types', 'i_o_types.id', '=', 'account_classes.io_type_id');
    }
}