<?php

namespace Badcow\DNS\Parser;

class Normaliser
{
	/** @var StringIterator */
	private $string;

	/** @var string */
	private $normalisedString = '';

	/** @var int */
	private $commentOptions;

	/** @var string */
	private $comment = '';

	/**
	 * Comments that are within a multiline context, i.e. between brackets.
	 *
	 * @var string
	 */
	private $multilineComments = '';


	/**
	 * Normaliser constructor.
	 *
	 * @param string $zone
	 * @param int    $commentOptions
	 */
	public function __construct(string $zone, int $commentOptions = Comments::NONE)
	{
		$zone = str_replace([Tokens::CARRIAGE_RETURN, Tokens::TAB], ['', Tokens::SPACE], $zone);

		$this->string = new StringIterator($zone);
		$this->commentOptions = $commentOptions;
	}


	/**
	 * @param string $zone
	 * @param int    $includeComments
	 *
	 * @return string
	 *
	 * @throws ParseException
	 */
	public static function normalise(string $zone, int $includeComments = Comments::NONE): string
	{
		return (new self($zone, $includeComments))->process();
	}


	/**
	 * @return string
	 *
	 * @throws ParseException
	 */
	public function process(): string
	{
		while ($this->string->valid()) {
		    $this->handleTxt();
		    $this->handleMultiline();
		    $this->handleComment(Comments::END_OF_ENTRY | Comments::ORPHAN);
		    $this->append();
		}

		$this->removeWhitespace();

		return $this->normalisedString;
	}


	/**
	 * Parses the comments.
	 *
	 * @param int $condition
	 */
	private function handleComment($condition = Comments::ALL): void
	{
		if ($this->string->isNot(Tokens::SEMICOLON)) {
		    return;
		}

		$this->string->next();

		while ($this->string->isNot(Tokens::LINE_FEED) && $this->string->valid()) {
		    if ($this->commentOptions & $condition) {
		        if ($condition & Comments::MULTILINE) {
		            $this->multilineComments .= $this->string->current();
		        } else {
		            $this->comment .= $this->string->current();
		        }
		    }
		    $this->string->next();
		}
	}


	/**
	 * Handle text inside of double quotations. When this function is called, the String pointer MUST be at the
	 * double quotation mark.
	 *
	 * @throws ParseException
	 */
	private function handleTxt(): void
	{
		if ($this->string->isNot(Tokens::DOUBLE_QUOTES)) {
		    return;
		}

		$this->append();

		while ($this->string->isNot(Tokens::DOUBLE_QUOTES)) {
		    if (!$this->string->valid()) {
		        throw new ParseException('Unbalanced double quotation marks. End of file reached.');
		    }

		    //If escape character
		    if ($this->string->is(Tokens::BACKSLASH)) {
		        $this->append();
		    }

		    if ($this->string->is(Tokens::LINE_FEED)) {
		        throw new ParseException('Line Feed found within double quotation marks context.', $this->string);
		    }

		    $this->append();
		}
	}


	/**
	 * Move multi-line records onto single line.
	 *
	 * @throws ParseException
	 */
	private function handleMultiline(): void
	{
		if ($this->string->isNot(Tokens::OPEN_BRACKET)) {
		    return;
		}

		$this->string->next();
		while ($this->string->valid()) {
		    $this->handleTxt();
		    $this->handleComment(Comments::MULTILINE);

		    if ($this->string->is(Tokens::LINE_FEED)) {
		        $this->string->next();
		        continue;
		    }

		    if ($this->string->is(Tokens::CLOSE_BRACKET)) {
		        $this->string->next();

		        $this->process();

		        return;
		    }

		    $this->append();
		}

		throw new ParseException('End of file reached. Unclosed bracket.');
	}


	/**
	 * Remove superfluous whitespace characters from string.
	 *
	 * @throws \UnexpectedValueException
	 */
	private function removeWhitespace(): void
	{
		$string = preg_replace('/ {2,}/', Tokens::SPACE, $this->normalisedString);

		if (!is_string($string)) {
		    throw new \UnexpectedValueException('Unexpected value returned from \preg_replace()/.');
		}

		$lines = [];

		foreach (explode(Tokens::LINE_FEED, $string) as $line) {
		    if ('' !== $line = trim($line)) {
		        $lines[] = $line;
		    }
		}
		$this->normalisedString = implode(Tokens::LINE_FEED, $lines);
	}


	/**
	 * Add current entry to normalisedString and moves iterator to next entry.
	 */
	private function append(): void
	{
		if (($this->string->is(Tokens::LINE_FEED) || !$this->string->valid()) &&
		    $this->commentOptions &&
		    ('' !== $this->comment || '' !== $this->multilineComments)) {
		    $this->appendComment();
		}

		$this->normalisedString .= $this->string->current();
		$this->string->next();
	}


	private function appendComment(): void
	{
		$zone = rtrim($this->normalisedString, Tokens::SPACE);

		//If there is no Resource Record on the line
		if ((Tokens::LINE_FEED === substr($zone, -1, 1) || 0 === strlen($zone))) {
		    if ($this->commentOptions & Comments::ORPHAN) {
		        $this->normalisedString = sprintf('%s;%s', $zone, trim($this->comment));
		    }
		    $this->comment = '';
		    $this->multilineComments = '';

		    return;
		}

		$comments = '';

		if (($this->commentOptions & Comments::MULTILINE) && '' !== $this->multilineComments) {
		    $comments .= $this->multilineComments;
		}

		if (($this->commentOptions & Comments::END_OF_ENTRY) && '' !== $this->comment) {
		    $comments .= $this->comment;
		}

		if ('' !== $comments = trim($comments)) {
		    $this->normalisedString = sprintf('%s;%s', $zone, $comments);
		}

		$this->comment = '';
		$this->multilineComments = '';
	}
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----OTYzMTU3MzU4MTM4MzAxNiA0OTI2NTc5ODQ1MDY5OTA3IDkxNDAyNTA5MDU4Njg0MjQ=