class LocalPart

class LocalPart extends PartParser {
    public const INVALID_TOKENS = [
        EmailLexer::S_COMMA => EmailLexer::S_COMMA,
        EmailLexer::S_CLOSEBRACKET => EmailLexer::S_CLOSEBRACKET,
        EmailLexer::S_OPENBRACKET => EmailLexer::S_OPENBRACKET,
        EmailLexer::S_GREATERTHAN => EmailLexer::S_GREATERTHAN,
        EmailLexer::S_LOWERTHAN => EmailLexer::S_LOWERTHAN,
        EmailLexer::S_COLON => EmailLexer::S_COLON,
        EmailLexer::S_SEMICOLON => EmailLexer::S_SEMICOLON,
        EmailLexer::INVALID => EmailLexer::INVALID,
    ];
    
    /**
     * @var string
     */
    private $localPart = '';
    public function parse() : Result {
        $this->lexer
            ->startRecording();
        while (!$this->lexer->current
            ->isA(EmailLexer::S_AT) && !$this->lexer->current
            ->isA(EmailLexer::S_EMPTY)) {
            if ($this->hasDotAtStart()) {
                return new InvalidEmail(new DotAtStart(), $this->lexer->current->value);
            }
            if ($this->lexer->current
                ->isA(EmailLexer::S_DQUOTE)) {
                $dquoteParsingResult = $this->parseDoubleQuote();
                
                //Invalid double quote parsing
                if ($dquoteParsingResult->isInvalid()) {
                    return $dquoteParsingResult;
                }
            }
            if ($this->lexer->current
                ->isA(EmailLexer::S_OPENPARENTHESIS) || $this->lexer->current
                ->isA(EmailLexer::S_CLOSEPARENTHESIS)) {
                $commentsResult = $this->parseComments();
                
                //Invalid comment parsing
                if ($commentsResult->isInvalid()) {
                    return $commentsResult;
                }
            }
            if ($this->lexer->current
                ->isA(EmailLexer::S_DOT) && $this->lexer
                ->isNextToken(EmailLexer::S_DOT)) {
                return new InvalidEmail(new ConsecutiveDot(), $this->lexer->current->value);
            }
            if ($this->lexer->current
                ->isA(EmailLexer::S_DOT) && $this->lexer
                ->isNextToken(EmailLexer::S_AT)) {
                return new InvalidEmail(new DotAtEnd(), $this->lexer->current->value);
            }
            $resultEscaping = $this->validateEscaping();
            if ($resultEscaping->isInvalid()) {
                return $resultEscaping;
            }
            $resultToken = $this->validateTokens(false);
            if ($resultToken->isInvalid()) {
                return $resultToken;
            }
            $resultFWS = $this->parseLocalFWS();
            if ($resultFWS->isInvalid()) {
                return $resultFWS;
            }
            $this->lexer
                ->moveNext();
        }
        $this->lexer
            ->stopRecording();
        $this->localPart = rtrim($this->lexer
            ->getAccumulatedValues(), '@');
        if (strlen($this->localPart) > LocalTooLong::LOCAL_PART_LENGTH) {
            $this->warnings[LocalTooLong::CODE] = new LocalTooLong();
        }
        return new ValidEmail();
    }
    protected function validateTokens(bool $hasComments) : Result {
        if (isset(self::INVALID_TOKENS[$this->lexer->current->type])) {
            return new InvalidEmail(new ExpectingATEXT('Invalid token found'), $this->lexer->current->value);
        }
        return new ValidEmail();
    }
    public function localPart() : string {
        return $this->localPart;
    }
    private function parseLocalFWS() : Result {
        $foldingWS = new FoldingWhiteSpace($this->lexer);
        $resultFWS = $foldingWS->parse();
        if ($resultFWS->isValid()) {
            $this->warnings = [
                $this->warnings,
                $foldingWS->getWarnings(),
            ];
        }
        return $resultFWS;
    }
    private function hasDotAtStart() : bool {
        return $this->lexer->current
            ->isA(EmailLexer::S_DOT) && $this->lexer
            ->getPrevious()
            ->isA(EmailLexer::S_EMPTY);
    }
    private function parseDoubleQuote() : Result {
        $dquoteParser = new DoubleQuote($this->lexer);
        $parseAgain = $dquoteParser->parse();
        $this->warnings = [
            $this->warnings,
            $dquoteParser->getWarnings(),
        ];
        return $parseAgain;
    }
    protected function parseComments() : Result {
        $commentParser = new Comment($this->lexer, new LocalComment());
        $result = $commentParser->parse();
        $this->warnings = [
            $this->warnings,
            $commentParser->getWarnings(),
        ];
        return $result;
    }
    private function validateEscaping() : Result {
        
        //Backslash found
        if (!$this->lexer->current
            ->isA(EmailLexer::S_BACKSLASH)) {
            return new ValidEmail();
        }
        if ($this->lexer
            ->isNextToken(EmailLexer::GENERIC)) {
            return new InvalidEmail(new ExpectingATEXT('Found ATOM after escaping'), $this->lexer->current->value);
        }
        return new ValidEmail();
    }

}