<?php

namespace App;

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

class PersonTarget extends Model
{
    /**************************************************************************
     * DIRECT RELATIONS                                                       *
     **************************************************************************/
    
    /**
     * Get the IOType of the target.
     *
     * @return Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function ioType()
    {
        return $this->belongsTo('App\IOType');
    }
    
    /**
     * Get the actuals connected with the target.
     *
     * @return Illuminate\Database\Eloquent\Relations\HasMany
     */
    public function actuals()
    {
        return $this->hasMany('App\SubBooking');
    }

    public function person()
    {
        return $this->belongsTo('App\Person');
    }

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


    /**************************************************************************
     * INDIRECT PROPERTIES                                                    *
     **************************************************************************/
    
    /**
     * Get the signed amount of the target.
     *
     * @return float
     */
    public function signedAmount()
    {
        return $this->amount * $this->ioType->factor;
    }

    /**
     * Return the sum of all actuals belonging to this target
     *
     * @return float 
     */
    public function actualsSum() {
        $sum = 0;

        foreach ($this->actuals as $actual) {
            $sum += $actual->signedAmount();
        }

        return $sum;
    }

    /**
     * Get the difference of target and actually payed amount so far. I. e.
     * return the amount still to be payed.
     *
     * @return float
     */
    public function difference() {
        return $this->signedAmount() - $this->actualsSum();
    }

    /**
     * Return true, if the target is paid and therefore closed.
     *
     * @return boolean
     */
    public function isPaid() {
        return $this->difference() == 0;
    }

    /**************************************************************************
     * COLLECTIONS FILTERED BY PAYMENT STATES                                 *
     **************************************************************************/

    /*
     * Get all targets which are paid off.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function open()
    {
        return PersonTarget::queryWhere('open');
    }
    
    /*
     * Get all targets which are paid off.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function paid()
    {
        return PersonTarget::queryWhere('paid');
    }

    /*
     * Get all targets which are underpaid.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function underpaid()
    {
        return PersonTarget::queryWhere('underpaid');
    }

    /*
     * Get all targets which are overpaid.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function overpaid()
    {
        return PersonTarget::queryWhere('overpaid');
    }

    /*
     * Get all targets which are a receivable.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function receivable()
    {
        return PersonTarget::queryWhere('receivable');
    }

    /*
     * Get all targets which are a debt.
     *
     * @return Illuminate\Database\Eloquent\Collection
     */
    public static function debt()
    {
        return PersonTarget::queryWhere('debt');
    }

    /*
     * Get the person targets which satisfy a given condition.
     * Possible values for $cond are:
     *
     * 'paid'       - all targets, which are paid
     * 'underpaid'  - all targets which are underpaid
     * 'overpaid'   - all targets which are overpaid
     * 'receivable' - all targets which are a receivable, i. e. have a positive
     *                difference between target and actual value.
     * 'debt'       - all targets which are a debt, i. e. have a negative
     *                difference between target and actual value.
     *
     * @param  string $cond
     * @return array
     */
    private static function queryWhere($cond)
    {
        // Set the having clause of the query according to the $cond argument.
        $having = true;

        switch ($cond) {
            case 'paid':
                $having = 'target = actual';
                break;
            case 'open':
                $having = 'target != actual';
                break;
            case 'underpaid':
                $having = '(target > 0 AND target > actual) OR ' .
                          '(target < 0 AND target < actual)';
                break;
            case 'overpaid':
                $having = '(target > 0 AND target < actual) OR ' .
                          '(target < 0 AND target > actual)';
                break;
            case 'receivable':
                $having = 'target > actual';
                break;
            case 'debt':
                $having = 'target < actual';
                break;
        }

        // Run the database query to retreive the data from the database.
        $selection = DB::select('
            SELECT
                p_t.*,
                p_t.amount * i_o2.factor AS target,
                IFNULL(SUM(i_o1.factor * s_b.amount), 0) AS actual
            FROM person_targets p_t
                INNER JOIN i_o_types i_o2 ON i_o2.id = p_t.io_type_id
                LEFT JOIN sub_bookings s_b ON p_t.id = s_b.person_target_id
                LEFT JOIN account_types a_t ON a_t.id = s_b.account_type_id
                LEFT JOIN account_classes a_c ON a_c.id = a_t.account_class_id
                LEFT JOIN i_o_types i_o1 ON i_o1.id = a_c.io_type_id
            GROUP BY p_t.id
            HAVING ' . $having . '
            ORDER BY p_t.date, p_t.reference, p_t.person_id;');

        // Remove the unused columns 'target' and 'actual' from the query
        // result.
        // This is not necessary, unless you want to save the hydrated models to
        // the databse. In this case we would get an error since the
        // peron_targets table has no column 'target' and 'actual'.
        foreach ($selection as $personTarget) {
            unset($personTarget->target);
            unset($personTarget->actual);
        }

        // Create a collection of PersonTargets from the raw query result.
        return PersonTarget::hydrate($selection);
    }
}