<?php
/**
 * RecurringRepository.php
 * Copyright (c) 2018 thegrumpydictator@gmail.com
 *
 * This file is part of Firefly III.
 *
 * Firefly III is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Firefly III is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Firefly III. If not, see <http://www.gnu.org/licenses/>.
 */

declare(strict_types=1);

namespace FireflyIII\Repositories\Recurring;

use Carbon\Carbon;
use FireflyIII\Exceptions\FireflyException;
use FireflyIII\Factory\RecurrenceFactory;
use FireflyIII\Helpers\Collector\TransactionCollectorInterface;
use FireflyIII\Helpers\Filter\InternalTransferFilter;
use FireflyIII\Models\Note;
use FireflyIII\Models\Preference;
use FireflyIII\Models\Recurrence;
use FireflyIII\Models\RecurrenceMeta;
use FireflyIII\Models\RecurrenceRepetition;
use FireflyIII\Models\RecurrenceTransaction;
use FireflyIII\Models\RecurrenceTransactionMeta;
use FireflyIII\Models\TransactionJournal;
use FireflyIII\Models\TransactionJournalMeta;
use FireflyIII\Services\Internal\Destroy\RecurrenceDestroyService;
use FireflyIII\Services\Internal\Update\RecurrenceUpdateService;
use FireflyIII\User;
use Illuminate\Pagination\LengthAwarePaginator;
use Illuminate\Support\Collection;
use Log;

/**
 *
 * Class RecurringRepository
 *
 * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
 * @SuppressWarnings(PHPMD.ExcessiveClassComplexity)
 */
class RecurringRepository implements RecurringRepositoryInterface
{
    /** @var User */
    private $user;

    /**
     * Constructor.
     */
    public function __construct()
    {
        if ('testing' === env('APP_ENV')) {
            Log::warning(sprintf('%s should not be instantiated in the TEST environment!', \get_class($this)));
        }
    }

    /**
     * Destroy a recurring transaction.
     *
     * @param Recurrence $recurrence
     */
    public function destroy(Recurrence $recurrence): void
    {
        /** @var RecurrenceDestroyService $service */
        $service = app(RecurrenceDestroyService::class);
        $service->destroy($recurrence);
    }

    /**
     * Returns all of the user's recurring transactions.
     *
     * @return Collection
     */
    public function get(): Collection
    {
        return $this->user->recurrences()
                          ->with(['TransactionCurrency', 'TransactionType', 'RecurrenceRepetitions', 'RecurrenceTransactions'])
                          ->orderBy('active', 'DESC')
                          ->orderBy('transaction_type_id', 'ASC')
                          ->orderBy('title', 'ASC')
                          ->get();
    }

    /**
     * Get ALL recurring transactions.
     *
     * @return Collection
     */
    public function getAll(): Collection
    {
        // grab ALL recurring transactions:
        return Recurrence
            ::with(['TransactionCurrency', 'TransactionType', 'RecurrenceRepetitions', 'RecurrenceTransactions'])
            ->orderBy('active', 'DESC')
            ->orderBy('title', 'ASC')
            ->get();
    }

    /**
     * Get the budget ID from a recurring transaction transaction.
     *
     * @param RecurrenceTransaction $recTransaction
     *
     * @return null|int
     */
    public function getBudget(RecurrenceTransaction $recTransaction): ?int
    {
        $return = 0;
        /** @var RecurrenceTransactionMeta $meta */
        foreach ($recTransaction->recurrenceTransactionMeta as $meta) {
            if ('budget_id' === $meta->name) {
                $return = (int)$meta->value;
            }
        }

        return 0 === $return ? null : $return;
    }

    /**
     * Get the category from a recurring transaction transaction.
     *
     * @param RecurrenceTransaction $recTransaction
     *
     * @return null|string
     */
    public function getCategory(RecurrenceTransaction $recTransaction): ?string
    {
        $return = '';
        /** @var RecurrenceTransactionMeta $meta */
        foreach ($recTransaction->recurrenceTransactionMeta as $meta) {
            if ('category_name' === $meta->name) {
                $return = (string)$meta->value;
            }
        }

        return '' === $return ? null : $return;
    }

    /**
     * Returns the journals created for this recurrence, possibly limited by time.
     *
     * @param Recurrence  $recurrence
     * @param Carbon|null $start
     * @param Carbon|null $end
     *
     * @return int
     */
    public function getJournalCount(Recurrence $recurrence, Carbon $start = null, Carbon $end = null): int
    {
        $query = TransactionJournal
            ::leftJoin('journal_meta', 'journal_meta.transaction_journal_id', '=', 'transaction_journals.id')
            ->where('transaction_journals.user_id', $recurrence->user_id)
            ->whereNull('transaction_journals.deleted_at')
            ->where('journal_meta.name', 'recurrence_id')
            ->where('journal_meta.data', '"' . $recurrence->id . '"');
        if (null !== $start) {
            $query->where('transaction_journals.date', '>=', $start->format('Y-m-d 00:00:00'));
        }
        if (null !== $end) {
            $query->where('transaction_journals.date', '<=', $end->format('Y-m-d 00:00:00'));
        }

        return $query->get(['transaction_journals.*'])->count();
    }

    /**
     * Get journal ID's for journals created by this recurring transaction.
     *
     * @param Recurrence $recurrence
     *
     * @return array
     */
    public function getJournalIds(Recurrence $recurrence): array
    {
        return TransactionJournalMeta::leftJoin('transaction_journals', 'transaction_journals.id', '=', 'journal_meta.transaction_journal_id')
                                     ->where('transaction_journals.user_id', $this->user->id)
                                     ->where('journal_meta.name', '=', 'recurrence_id')
                                     ->where('journal_meta.data', '=', json_encode((string)$recurrence->id))
                                     ->get(['journal_meta.transaction_journal_id'])->pluck('transaction_journal_id')->toArray();
    }

    /**
     * Get the notes.
     *
     * @param Recurrence $recurrence
     *
     * @return string
     */
    public function getNoteText(Recurrence $recurrence): string
    {
        /** @var Note $note */
        $note = $recurrence->notes()->first();
        if (null !== $note) {
            return (string)$note->text;
        }

        return '';
    }

    /**
     * Generate events in the date range.
     *
     * @param RecurrenceRepetition $repetition
     * @param Carbon               $start
     * @param Carbon               $end
     *
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    public function getOccurrencesInRange(RecurrenceRepetition $repetition, Carbon $start, Carbon $end): array
    {
        $occurrences = [];
        $mutator     = clone $start;
        $mutator->startOfDay();
        $skipMod = $repetition->repetition_skip + 1;
        Log::debug(sprintf('Calculating occurrences for rep type "%s"', $repetition->repetition_type));
        Log::debug(sprintf('Mutator is now: %s', $mutator->format('Y-m-d')));

        if ('daily' === $repetition->repetition_type) {
            $occurrences = $this->getDailyInRange($mutator, $end, $skipMod);
        }
        if ('weekly' === $repetition->repetition_type) {
            $occurrences = $this->getWeeklyInRange($mutator, $end, $skipMod, $repetition->repetition_moment);
        }
        if ('monthly' === $repetition->repetition_type) {
            $occurrences = $this->getMonthlyInRange($mutator, $end, $skipMod, $repetition->repetition_moment);
        }
        if ('ndom' === $repetition->repetition_type) {
            $occurrences = $this->getNdomInRange($mutator, $end, $skipMod, $repetition->repetition_moment);
        }
        if ('yearly' === $repetition->repetition_type) {
            $occurrences = $this->getYearlyInRange($mutator, $end, $skipMod, $repetition->repetition_moment);
        }


        // filter out all the weekend days:
        $occurrences = $this->filterWeekends($repetition, $occurrences);

        return $occurrences;
    }

    /**
     * Get the tags from the recurring transaction.
     *
     * @param Recurrence $recurrence
     *
     * @return array
     */
    public function getTags(Recurrence $recurrence): array
    {
        $tags = [];
        /** @var RecurrenceMeta $meta */
        foreach ($recurrence->recurrenceMeta as $meta) {
            if ('tags' === $meta->name && '' !== $meta->value) {
                $tags = explode(',', $meta->value);
            }
        }

        return $tags;
    }

    /**
     * @param Recurrence $recurrence
     * @param int        $page
     * @param int        $pageSize
     *
     * @return LengthAwarePaginator
     */
    public function getTransactionPaginator(Recurrence $recurrence, int $page, int $pageSize): LengthAwarePaginator
    {
        $journalMeta = TransactionJournalMeta
            ::leftJoin('transaction_journals', 'transaction_journals.id', '=', 'journal_meta.transaction_journal_id')
            ->whereNull('transaction_journals.deleted_at')
            ->where('transaction_journals.user_id', $this->user->id)
            ->where('name', 'recurrence_id')
            ->where('data', json_encode((string)$recurrence->id))
            ->get()->pluck('transaction_journal_id')->toArray();
        $search      = [];
        foreach ($journalMeta as $journalId) {
            $search[] = ['id' => (int)$journalId];
        }
        /** @var TransactionCollectorInterface $collector */
        $collector = app(TransactionCollectorInterface::class);
        $collector->setUser($recurrence->user);
        $collector->withOpposingAccount()->setAllAssetAccounts()->withCategoryInformation()->withBudgetInformation()->setLimit($pageSize)->setPage($page);
        // filter on specific journals.
        $collector->removeFilter(InternalTransferFilter::class);
        $collector->setJournals(new Collection($search));

        return $collector->getPaginatedTransactions();
    }

    /**
     * @param Recurrence $recurrence
     *
     * @return Collection
     */
    public function getTransactions(Recurrence $recurrence): Collection
    {
        $journalMeta = TransactionJournalMeta
            ::leftJoin('transaction_journals', 'transaction_journals.id', '=', 'journal_meta.transaction_journal_id')
            ->whereNull('transaction_journals.deleted_at')
            ->where('transaction_journals.user_id', $this->user->id)
            ->where('name', 'recurrence_id')
            ->where('data', json_encode((string)$recurrence->id))
            ->get()->pluck('transaction_journal_id')->toArray();
        $search      = [];
        foreach ($journalMeta as $journalId) {
            $search[] = ['id' => (int)$journalId];
        }
        /** @var TransactionCollectorInterface $collector */
        $collector = app(TransactionCollectorInterface::class);
        $collector->setUser($recurrence->user);
        $collector->withOpposingAccount()->setAllAssetAccounts()->withCategoryInformation()->withBudgetInformation();
        // filter on specific journals.
        $collector->removeFilter(InternalTransferFilter::class);
        $collector->setJournals(new Collection($search));

        return $collector->getTransactions();
    }

    /**
     * Calculate the next X iterations starting on the date given in $date.
     *
     * @param RecurrenceRepetition $repetition
     * @param Carbon               $date
     * @param int                  $count
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    public function getXOccurrences(RecurrenceRepetition $repetition, Carbon $date, int $count): array
    {
        $skipMod     = $repetition->repetition_skip + 1;
        $occurrences = [];
        if ('daily' === $repetition->repetition_type) {
            $occurrences = $this->getXDailyOccurrences($date, $count, $skipMod);
        }
        if ('weekly' === $repetition->repetition_type) {
            $occurrences = $this->getXWeeklyOccurrences($date, $count, $skipMod, $repetition->repetition_moment);
        }
        if ('monthly' === $repetition->repetition_type) {
            $occurrences = $this->getXMonthlyOccurrences($date, $count, $skipMod, $repetition->repetition_moment);
        }
        if ('ndom' === $repetition->repetition_type) {
            $occurrences = $this->getXNDomOccurrences($date, $count, $skipMod, $repetition->repetition_moment);
        }
        if ('yearly' === $repetition->repetition_type) {
            $occurrences = $this->getXYearlyOccurrences($date, $count, $skipMod, $repetition->repetition_moment);
        }

        // filter out all the weekend days:
        $occurrences = $this->filterWeekends($repetition, $occurrences);

        return $occurrences;
    }

    /**
     * Parse the repetition in a string that is user readable.
     *
     * @param RecurrenceRepetition $repetition
     *
     * @return string
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    public function repetitionDescription(RecurrenceRepetition $repetition): string
    {
        /** @var Preference $pref */
        $pref     = app('preferences')->getForUser($this->user, 'language', config('firefly.default_language', 'en_US'));
        $language = $pref->data;
        if ('daily' === $repetition->repetition_type) {
            return (string)trans('firefly.recurring_daily', [], $language);
        }
        if ('weekly' === $repetition->repetition_type) {
            $dayOfWeek = trans(sprintf('config.dow_%s', $repetition->repetition_moment), [], $language);

            return (string)trans('firefly.recurring_weekly', ['weekday' => $dayOfWeek], $language);
        }
        if ('monthly' === $repetition->repetition_type) {
            return (string)trans('firefly.recurring_monthly', ['dayOfMonth' => $repetition->repetition_moment], $language);
        }
        if ('ndom' === $repetition->repetition_type) {
            $parts = explode(',', $repetition->repetition_moment);
            // first part is number of week, second is weekday.
            $dayOfWeek = trans(sprintf('config.dow_%s', $parts[1]), [], $language);

            return (string)trans('firefly.recurring_ndom', ['weekday' => $dayOfWeek, 'dayOfMonth' => $parts[0]], $language);
        }
        if ('yearly' === $repetition->repetition_type) {
            //
            $today       = Carbon::now()->endOfYear();
            $repDate     = Carbon::createFromFormat('Y-m-d', $repetition->repetition_moment);
            $diffInYears = $today->diffInYears($repDate);
            $repDate->addYears($diffInYears); // technically not necessary.
            $string = $repDate->formatLocalized((string)trans('config.month_and_day_no_year'));

            return (string)trans('firefly.recurring_yearly', ['date' => $string], $language);
        }

        return '';

    }

    /**
     * Set user for in repository.
     *
     * @param User $user
     */
    public function setUser(User $user): void
    {
        $this->user = $user;
    }

    /**
     * @param array $data
     *
     * @return Recurrence
     */
    public function store(array $data): Recurrence
    {
        $factory = new RecurrenceFactory;
        $factory->setUser($this->user);

        return $factory->create($data);
    }

    /**
     * Update a recurring transaction.
     *
     * @param Recurrence $recurrence
     * @param array      $data
     *
     * @return Recurrence
     * @throws FireflyException
     */
    public function update(Recurrence $recurrence, array $data): Recurrence
    {
        /** @var RecurrenceUpdateService $service */
        $service = app(RecurrenceUpdateService::class);

        return $service->update($recurrence, $data);
    }

    /**
     * Filters out all weekend entries, if necessary.
     *
     * @param RecurrenceRepetition $repetition
     * @param array                $dates
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
     */
    private function filterWeekends(RecurrenceRepetition $repetition, array $dates): array
    {
        if ((int)$repetition->weekend === RecurrenceRepetition::WEEKEND_DO_NOTHING) {
            Log::debug('Repetition will not be filtered on weekend days.');

            return $dates;
        }
        $return = [];
        /** @var Carbon $date */
        foreach ($dates as $date) {
            $isWeekend = $date->isWeekend();
            if (!$isWeekend) {
                $return[] = clone $date;
                Log::debug(sprintf('Date is %s, not a weekend date.', $date->format('D d M Y')));
                continue;
            }

            // is weekend and must set back to Friday?
            if ($repetition->weekend === RecurrenceRepetition::WEEKEND_TO_FRIDAY) {
                $clone = clone $date;
                $clone->addDays(5 - $date->dayOfWeekIso);
                Log::debug(
                    sprintf('Date is %s, and this is in the weekend, so corrected to %s (Friday).', $date->format('D d M Y'), $clone->format('D d M Y'))
                );
                $return[] = clone $clone;
                continue;
            }

            // postpone to Monday?
            if ($repetition->weekend === RecurrenceRepetition::WEEKEND_TO_MONDAY) {
                $clone = clone $date;
                $clone->addDays(8 - $date->dayOfWeekIso);
                Log::debug(
                    sprintf('Date is %s, and this is in the weekend, so corrected to %s (Monday).', $date->format('D d M Y'), $clone->format('D d M Y'))
                );
                $return[] = $clone;
                continue;
            }
            Log::debug(sprintf('Date is %s, removed from final result', $date->format('D d M Y')));
        }

        // filter unique dates
        Log::debug(sprintf('Count before filtering: %d', \count($dates)));
        $collection = new Collection($return);
        $filtered   = $collection->unique();
        $return     = $filtered->toArray();

        Log::debug(sprintf('Count after filtering: %d', \count($return)));

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Get the number of daily occurrences for a recurring transaction until date $end is reached. Will skip every $skipMod-1 occurrences.
     *
     * @param Carbon $start
     * @param Carbon $end
     * @param int    $skipMod
     *
     * @return array
     */
    private function getDailyInRange(Carbon $start, Carbon $end, int $skipMod): array
    {
        $return   = [];
        $attempts = 0;
        Log::debug('Rep is daily. Start of loop.');
        while ($start <= $end) {
            Log::debug(sprintf('Mutator is now: %s', $start->format('Y-m-d')));
            if (0 === $attempts % $skipMod) {
                Log::debug(sprintf('Attempts modulo skipmod is zero, include %s', $start->format('Y-m-d')));
                $return[] = clone $start;
            }
            $start->addDay();
            $attempts++;
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Get the number of daily occurrences for a recurring transaction until date $end is reached. Will skip every $skipMod-1 occurrences.
     *
     * @param Carbon $start
     * @param Carbon $end
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    private function getMonthlyInRange(Carbon $start, Carbon $end, int $skipMod, string $moment): array
    {
        $return     = [];
        $attempts   = 0;
        $dayOfMonth = (int)$moment;
        Log::debug(sprintf('Day of month in repetition is %d', $dayOfMonth));
        Log::debug(sprintf('Start is %s.', $start->format('Y-m-d')));
        Log::debug(sprintf('End is %s.', $end->format('Y-m-d')));
        if ($start->day > $dayOfMonth) {
            Log::debug('Add a month.');
            // day has passed already, add a month.
            $start->addMonth();
        }
        Log::debug(sprintf('Start is now %s.', $start->format('Y-m-d')));
        Log::debug('Start loop.');
        while ($start < $end) {
            Log::debug(sprintf('Mutator is now %s.', $start->format('Y-m-d')));
            $domCorrected = min($dayOfMonth, $start->daysInMonth);
            Log::debug(sprintf('DoM corrected is %d', $domCorrected));
            $start->day = $domCorrected;
            Log::debug(sprintf('Mutator is now %s.', $start->format('Y-m-d')));
            Log::debug(sprintf('$attempts %% $skipMod === 0 is %s', var_export(0 === $attempts % $skipMod, true)));
            Log::debug(sprintf('$start->lte($mutator) is %s', var_export($start->lte($start), true)));
            Log::debug(sprintf('$end->gte($mutator) is %s', var_export($end->gte($start), true)));
            if (0 === $attempts % $skipMod && $start->lte($start) && $end->gte($start)) {
                Log::debug(sprintf('ADD %s to return!', $start->format('Y-m-d')));
                $return[] = clone $start;
            }
            $attempts++;
            $start->endOfMonth()->startOfDay()->addDay();
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Get the number of daily occurrences for a recurring transaction until date $end is reached. Will skip every $skipMod-1 occurrences.
     *
     * @param Carbon $start
     * @param Carbon $end
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     */
    private function getNdomInRange(Carbon $start, Carbon $end, int $skipMod, string $moment): array
    {
        $return   = [];
        $attempts = 0;
        $start->startOfMonth();
        // this feels a bit like a cop out but why reinvent the wheel?
        $counters   = [1 => 'first', 2 => 'second', 3 => 'third', 4 => 'fourth', 5 => 'fifth',];
        $daysOfWeek = [1 => 'Monday', 2 => 'Tuesday', 3 => 'Wednesday', 4 => 'Thursday', 5 => 'Friday', 6 => 'Saturday', 7 => 'Sunday',];
        $parts      = explode(',', $moment);
        while ($start <= $end) {
            $string    = sprintf('%s %s of %s %s', $counters[$parts[0]], $daysOfWeek[$parts[1]], $start->format('F'), $start->format('Y'));
            $newCarbon = new Carbon($string);
            if (0 === $attempts % $skipMod) {
                $return[] = clone $newCarbon;
            }
            $attempts++;
            $start->endOfMonth()->addDay();
        }

        return $return;
    }

    /**
     * Get the number of daily occurrences for a recurring transaction until date $end is reached. Will skip every $skipMod-1 occurrences.
     *
     * @param Carbon $start
     * @param Carbon $end
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    private function getWeeklyInRange(Carbon $start, Carbon $end, int $skipMod, string $moment): array
    {
        $return   = [];
        $attempts = 0;
        Log::debug('Rep is weekly.');
        // monday = 1
        // sunday = 7
        $dayOfWeek = (int)$moment;
        Log::debug(sprintf('DoW in repetition is %d, in mutator is %d', $dayOfWeek, $start->dayOfWeekIso));
        if ($start->dayOfWeekIso > $dayOfWeek) {
            // day has already passed this week, add one week:
            $start->addWeek();
            Log::debug(sprintf('Jump to next week, so mutator is now: %s', $start->format('Y-m-d')));
        }
        // today is wednesday (3), expected is friday (5): add two days.
        // today is friday (5), expected is monday (1), subtract four days.
        Log::debug(sprintf('Mutator is now: %s', $start->format('Y-m-d')));
        $dayDifference = $dayOfWeek - $start->dayOfWeekIso;
        $start->addDays($dayDifference);
        Log::debug(sprintf('Mutator is now: %s', $start->format('Y-m-d')));
        while ($start <= $end) {
            if (0 === $attempts % $skipMod && $start->lte($start) && $end->gte($start)) {
                Log::debug('Date is in range of start+end, add to set.');
                $return[] = clone $start;
            }
            $attempts++;
            $start->addWeek();
            Log::debug(sprintf('Mutator is now (end of loop): %s', $start->format('Y-m-d')));
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Calculates the number of daily occurrences for a recurring transaction, starting at the date, until $count is reached. It will skip
     * over $skipMod -1 recurrences.
     *
     * @param Carbon $date
     * @param int    $count
     * @param int    $skipMod
     *
     * @return array
     */
    private function getXDailyOccurrences(Carbon $date, int $count, int $skipMod): array
    {
        $return   = [];
        $mutator  = clone $date;
        $total    = 0;
        $attempts = 0;
        while ($total < $count) {
            $mutator->addDay();
            if (0 === $attempts % $skipMod) {
                $return[] = clone $mutator;
                $total++;
            }
            $attempts++;
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Calculates the number of monthly occurrences for a recurring transaction, starting at the date, until $count is reached. It will skip
     * over $skipMod -1 recurrences.
     *
     * @param Carbon $date
     * @param int    $count
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     */
    private function getXMonthlyOccurrences(Carbon $date, int $count, int $skipMod, string $moment): array
    {
        $return   = [];
        $mutator  = clone $date;
        $total    = 0;
        $attempts = 0;
        $mutator->addDay(); // always assume today has passed.
        $dayOfMonth = (int)$moment;
        if ($mutator->day > $dayOfMonth) {
            // day has passed already, add a month.
            $mutator->addMonth();
        }

        while ($total < $count) {
            $domCorrected = min($dayOfMonth, $mutator->daysInMonth);
            $mutator->day = $domCorrected;
            if (0 === $attempts % $skipMod) {
                $return[] = clone $mutator;
                $total++;
            }
            $attempts++;
            $mutator->endOfMonth()->addDay();
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Calculates the number of NDOM occurrences for a recurring transaction, starting at the date, until $count is reached. It will skip
     * over $skipMod -1 recurrences.
     *
     * @param Carbon $date
     * @param int    $count
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     */
    private function getXNDomOccurrences(Carbon $date, int $count, int $skipMod, string $moment): array
    {
        $return   = [];
        $total    = 0;
        $attempts = 0;
        $mutator  = clone $date;
        $mutator->addDay(); // always assume today has passed.
        $mutator->startOfMonth();
        // this feels a bit like a cop out but why reinvent the wheel?
        $counters   = [1 => 'first', 2 => 'second', 3 => 'third', 4 => 'fourth', 5 => 'fifth',];
        $daysOfWeek = [1 => 'Monday', 2 => 'Tuesday', 3 => 'Wednesday', 4 => 'Thursday', 5 => 'Friday', 6 => 'Saturday', 7 => 'Sunday',];
        $parts      = explode(',', $moment);

        while ($total < $count) {
            $string    = sprintf('%s %s of %s %s', $counters[$parts[0]], $daysOfWeek[$parts[1]], $mutator->format('F'), $mutator->format('Y'));
            $newCarbon = new Carbon($string);
            if (0 === $attempts % $skipMod) {
                $return[] = clone $newCarbon;
                $total++;
            }
            $attempts++;
            $mutator->endOfMonth()->addDay();
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Calculates the number of weekly occurrences for a recurring transaction, starting at the date, until $count is reached. It will skip
     * over $skipMod -1 recurrences.
     *
     * @param Carbon $date
     * @param int    $count
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     */
    private function getXWeeklyOccurrences(Carbon $date, int $count, int $skipMod, string $moment): array
    {
        $return   = [];
        $total    = 0;
        $attempts = 0;
        $mutator  = clone $date;
        // monday = 1
        // sunday = 7
        $mutator->addDay(); // always assume today has passed.
        $dayOfWeek = (int)$moment;
        if ($mutator->dayOfWeekIso > $dayOfWeek) {
            // day has already passed this week, add one week:
            $mutator->addWeek();
        }
        // today is wednesday (3), expected is friday (5): add two days.
        // today is friday (5), expected is monday (1), subtract four days.
        $dayDifference = $dayOfWeek - $mutator->dayOfWeekIso;
        $mutator->addDays($dayDifference);

        while ($total < $count) {
            if (0 === $attempts % $skipMod) {
                $return[] = clone $mutator;
                $total++;
            }
            $attempts++;
            $mutator->addWeek();
        }

        return $return;
    }

    /** @noinspection MoreThanThreeArgumentsInspection */

    /**
     * Calculates the number of yearly occurrences for a recurring transaction, starting at the date, until $count is reached. It will skip
     * over $skipMod -1 recurrences.
     *
     * @param Carbon $date
     * @param int    $count
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     */
    private function getXYearlyOccurrences(Carbon $date, int $count, int $skipMod, string $moment): array
    {
        $return     = [];
        $mutator    = clone $date;
        $total      = 0;
        $attempts   = 0;
        $date       = new Carbon($moment);
        $date->year = $mutator->year;
        if ($mutator > $date) {
            $date->addYear();
        }
        $obj = clone $date;
        while ($total < $count) {
            if (0 === $attempts % $skipMod) {
                $return[] = clone $obj;
                $total++;
            }
            $obj->addYears(1);
            $attempts++;
        }

        return $return;

    }

    /**
     * Get the number of daily occurrences for a recurring transaction until date $end is reached. Will skip every $skipMod-1 occurrences.
     *
     * @param Carbon $start
     * @param Carbon $end
     * @param int    $skipMod
     * @param string $moment
     *
     * @return array
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     */
    private function getYearlyInRange(Carbon $start, Carbon $end, int $skipMod, string $moment): array
    {
        $attempts   = 0;
        $date       = new Carbon($moment);
        $date->year = $start->year;
        $return     = [];
        if ($start > $date) {
            $date->addYear();

        }

        // is $date between $start and $end?
        $obj   = clone $date;
        $count = 0;
        while ($obj <= $end && $obj >= $start && $count < 10) {
            if (0 === $attempts % $skipMod) {
                $return[] = clone $obj;
            }
            $obj->addYears(1);
            $count++;
            $attempts++;
        }

        return $return;

    }
}