<?php

namespace SearchWP\Dependencies\Wamania\Snowball;

/**
 *
 * @link http://snowball.tartarus.org/algorithms/russian/stemmer.html
 * @author wamania
 *
 */
class Russian extends Stem
{
    /**
     * All russian vowels
     */
    protected static $vowels = array('а', 'е', 'и', 'о', 'у', 'ы', 'э', 'ю', 'я');
    protected static $perfectiveGerund = array(array('вшись', 'вши', 'в'), array('ывшись', 'ившись', 'ывши', 'ивши', 'ив', 'ыв'));
    protected static $adjective = array('ыми', 'ими', 'ему', 'ому', 'его', 'ого', 'ее', 'ие', 'ые', 'ое', 'ей', 'ий', 'ый', 'ой', 'ем', 'им', 'ым', 'ом', 'их', 'ых', 'ую', 'юю', 'ая', 'яя', 'ою', 'ею');
    protected static $participle = array(array('ем', 'нн', 'вш', 'ющ', 'щ'), array('ивш', 'ывш', 'ующ'));
    protected static $reflexive = array('ся', 'сь');
    protected static $verb = array(array('ешь', 'нно', 'ете', 'йте', 'ла', 'на', 'ли', 'й', 'л', 'ем', 'н', 'ло', 'но', 'ет', 'ют', 'ны', 'ть'), array('уйте', 'ило', 'ыло', 'ено', 'ила', 'ыла', 'ена', 'ейте', 'ены', 'ить', 'ыть', 'ишь', 'ите', 'или', 'ыли', 'ует', 'уют', 'ей', 'уй', 'ил', 'ыл', 'им', 'ым', 'ен', 'ят', 'ит', 'ыт', 'ую', 'ю'));
    protected static $noun = array('иями', 'ями', 'ами', 'ией', 'иям', 'ием', 'иях', 'ев', 'ов', 'ие', 'ье', 'еи', 'ии', 'ей', 'ой', 'ий', 'ям', 'ем', 'ам', 'ом', 'ах', 'ях', 'ию', 'ью', 'ия', 'ья', 'я', 'а', 'е', 'ы', 'ь', 'и', 'о', 'у', 'й', 'ю');
    protected static $superlative = array('ейше', 'ейш');
    protected static $derivational = array('ость', 'ост');
    /**
     * {@inheritdoc}
     */
    public function stem($word)
    {
        // we do ALL in UTF-8
        if (!Utf8::check($word)) {
            throw new \Exception('Word must be in UTF-8');
        }
        $this->word = Utf8::strtolower($word);
        // R2 is not used: R1 is defined in the same way as in the German stemmer
        $this->r1();
        $this->r2();
        $this->rv();
        // Do each of steps 1, 2 3 and 4.
        $this->step1();
        $this->step2();
        $this->step3();
        $this->step4();
        return $this->word;
    }
    /**
     * Step 1: Search for a PERFECTIVE GERUND ending. If one is found remove it, and that is then the end of step 1.
     * Otherwise try and remove a REFLEXIVE ending, and then search in turn for (1) an ADJECTIVAL, (2) a VERB or (3) a NOUN ending.
     * As soon as one of the endings (1) to (3) is found remove it, and terminate step 1.
     */
    public function step1()
    {
        // Search for a PERFECTIVE GERUND ending.
        // group 1
        if (($position = $this->searchIfInRv(self::$perfectiveGerund[0])) !== \false) {
            if ($this->inRv($position) && $this->checkGroup1($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        // group 2
        if (($position = $this->searchIfInRv(self::$perfectiveGerund[1])) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        // Otherwise try and remove a REFLEXIVE ending
        if (($position = $this->searchIfInRv(self::$reflexive)) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
            }
        }
        // then search in turn for (1) an ADJECTIVAL, (2) a VERB or (3) a NOUN ending.
        // As soon as one of the endings (1) to (3) is found remove it, and terminate step 1.
        if (($position = $this->searchIfInRv(self::$adjective)) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                if (($position2 = $this->search(self::$participle[0])) !== \false) {
                    if ($this->inRv($position2) && $this->checkGroup1($position2)) {
                        $this->word = Utf8::substr($this->word, 0, $position2);
                        return \true;
                    }
                }
                if (($position2 = $this->search(self::$participle[1])) !== \false) {
                    if ($this->inRv($position2)) {
                        $this->word = Utf8::substr($this->word, 0, $position2);
                        return \true;
                    }
                }
                return \true;
            }
        }
        if (($position = $this->searchIfInRv(self::$verb[0])) !== \false) {
            if ($this->inRv($position) && $this->checkGroup1($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        if (($position = $this->searchIfInRv(self::$verb[1])) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        if (($position = $this->searchIfInRv(self::$noun)) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        return \false;
    }
    /**
     * Step 2: If the word ends with и (i), remove it.
     */
    public function step2()
    {
        if (($position = $this->searchIfInRv(array('и'))) !== \false) {
            if ($this->inRv($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
        return \false;
    }
    /**
     * Step 3: Search for a DERIVATIONAL ending in R2 (i.e. the entire ending must lie in R2),
     * and if one is found, remove it.
     */
    public function step3()
    {
        if (($position = $this->searchIfInRv(self::$derivational)) !== \false) {
            if ($this->inR2($position)) {
                $this->word = Utf8::substr($this->word, 0, $position);
                return \true;
            }
        }
    }
    /**
     *  Step 4: (1) Undouble н (n), or, (2) if the word ends with a SUPERLATIVE ending, remove it
     *  and undouble н (n), or (3) if the word ends ь (') (soft sign) remove it.
     */
    public function step4()
    {
        // (2) if the word ends with a SUPERLATIVE ending, remove it
        if (($position = $this->searchIfInRv(self::$superlative)) !== \false) {
            $this->word = Utf8::substr($this->word, 0, $position);
        }
        // (1) Undouble н (n)
        if (($position = $this->searchIfInRv(array('нн'))) !== \false) {
            $this->word = Utf8::substr($this->word, 0, $position + 1);
            return \true;
        }
        // (3) if the word ends ь (') (soft sign) remove it
        if (($position = $this->searchIfInRv(array('ь'))) !== \false) {
            $this->word = Utf8::substr($this->word, 0, $position);
            return \true;
        }
    }
    /**
     *  In any word, RV is the region after the first vowel, or the end of the word if it contains no vowel.
     */
    protected function rv()
    {
        $length = Utf8::strlen($this->word);
        $this->rv = '';
        $this->rvIndex = $length;
        for ($i = 0; $i < $length; $i++) {
            $letter = Utf8::substr($this->word, $i, 1);
            if (\in_array($letter, self::$vowels)) {
                $this->rv = Utf8::substr($this->word, $i + 1);
                $this->rvIndex = $i + 1;
                return \true;
            }
        }
        return \false;
    }
    /**
     * group 1 endings must follow а (a) or я (ia)
     *
     * @param integer $position
     * @return boolean
     */
    private function checkGroup1($position)
    {
        if (!$this->inRv($position - 1)) {
            return \false;
        }
        $letter = Utf8::substr($this->word, $position - 1, 1);
        if ($letter == 'а' || $letter == 'я') {
            return \true;
        }
        return \false;
    }
}
