class FoldingWhiteSpace

class FoldingWhiteSpace extends PartParser {
    public const FWS_TYPES = [
        EmailLexer::S_SP,
        EmailLexer::S_HTAB,
        EmailLexer::S_CR,
        EmailLexer::S_LF,
        EmailLexer::CRLF,
    ];
    public function parse() : Result {
        if (!$this->isFWS()) {
            return new ValidEmail();
        }
        $previous = $this->lexer
            ->getPrevious();
        $resultCRLF = $this->checkCRLFInFWS();
        if ($resultCRLF->isInvalid()) {
            return $resultCRLF;
        }
        if ($this->lexer->current
            ->isA(EmailLexer::S_CR)) {
            return new InvalidEmail(new CRNoLF(), $this->lexer->current->value);
        }
        if ($this->lexer
            ->isNextToken(EmailLexer::GENERIC) && !$previous->isA(EmailLexer::S_AT)) {
            return new InvalidEmail(new AtextAfterCFWS(), $this->lexer->current->value);
        }
        if ($this->lexer->current
            ->isA(EmailLexer::S_LF) || $this->lexer->current
            ->isA(EmailLexer::C_NUL)) {
            return new InvalidEmail(new ExpectingCTEXT(), $this->lexer->current->value);
        }
        if ($this->lexer
            ->isNextToken(EmailLexer::S_AT) || $previous->isA(EmailLexer::S_AT)) {
            $this->warnings[CFWSNearAt::CODE] = new CFWSNearAt();
        }
        else {
            $this->warnings[CFWSWithFWS::CODE] = new CFWSWithFWS();
        }
        return new ValidEmail();
    }
    protected function checkCRLFInFWS() : Result {
        if (!$this->lexer->current
            ->isA(EmailLexer::CRLF)) {
            return new ValidEmail();
        }
        if (!$this->lexer
            ->isNextTokenAny(array(
            EmailLexer::S_SP,
            EmailLexer::S_HTAB,
        ))) {
            return new InvalidEmail(new CRLFX2(), $this->lexer->current->value);
        }
        
        //this has no coverage. Condition is repeated from above one
        if (!$this->lexer
            ->isNextTokenAny(array(
            EmailLexer::S_SP,
            EmailLexer::S_HTAB,
        ))) {
            return new InvalidEmail(new CRLFAtTheEnd(), $this->lexer->current->value);
        }
        return new ValidEmail();
    }
    protected function isFWS() : bool {
        if ($this->escaped()) {
            return false;
        }
        return in_array($this->lexer->current->type, self::FWS_TYPES);
    }

}