<?php
/**
 * PHPCompatibility, an external standard for PHP_CodeSniffer.
 *
 * @package   PHPCompatibility
 * @copyright 2012-2019 PHPCompatibility Contributors
 * @license   https://opensource.org/licenses/LGPL-3.0 LGPL3
 * @link      https://github.com/PHPCompatibility/PHPCompatibility
 */

namespace PHPCompatibility\Sniffs\Operators;

use PHPCompatibility\Sniff;
use PHPCompatibility\PHPCSHelper;
use PHP_CodeSniffer_File as File;
use PHP_CodeSniffer_Tokens as Tokens;

/**
 * Bitwise shifts by negative number will throw an ArithmeticError since PHP 7.0.
 *
 * PHP version 7.0
 *
 * @link https://wiki.php.net/rfc/integer_semantics
 * @link https://www.php.net/manual/en/migration70.incompatible.php#migration70.incompatible.integers.negative-bitshift
 *
 * @since 7.0.0
 */
class ForbiddenNegativeBitshiftSniff extends Sniff {

	/**
	 * Potential end tokens for which the end pointer has to be set back by one.
	 *
	 * {@internal The PHPCS `findEndOfStatement()` method is not completely consistent
	 * in how it returns the statement end. This is just a simple way to bypass
	 * the inconsistency for our purposes.}
	 *
	 * @since 8.2.0
	 *
	 * @var array
	 */
	private $inclusiveStopPoints = array(
		\T_COLON        => true,
		\T_COMMA        => true,
		\T_DOUBLE_ARROW => true,
		\T_SEMICOLON    => true,
	);

	/**
	 * Returns an array of tokens this test wants to listen for.
	 *
	 * @since 7.0.0
	 * @since 8.2.0 Now registers all bitshift tokens, not just bitshift right (`T_SR`).
	 *
	 * @return array
	 */
	public function register() {
		return array(
			\T_SL,
			\T_SL_EQUAL,
			\T_SR,
			\T_SR_EQUAL,
		);
	}

	/**
	 * Processes this test, when one of its tokens is encountered.
	 *
	 * @since 7.0.0
	 *
	 * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned.
	 * @param int                   $stackPtr  The position of the current token
	 *                                         in the stack passed in $tokens.
	 *
	 * @return void
	 */
	public function process( File $phpcsFile, $stackPtr ) {
		if ( $this->supportsAbove( '7.0' ) === false ) {
			return;
		}

		$tokens = $phpcsFile->getTokens();

		// Determine the start and end of the part of the statement we need to examine.
		$start = ( $stackPtr + 1 );
		$next  = $phpcsFile->findNext( Tokens::$emptyTokens, $start, null, true );
		if ( $next !== false && $tokens[ $next ]['code'] === \T_OPEN_PARENTHESIS ) {
			$start = ( $next + 1 );
		}

		$end = PHPCSHelper::findEndOfStatement( $phpcsFile, $start );
		if ( isset( $this->inclusiveStopPoints[ $tokens[ $end ]['code'] ] ) === true ) {
			--$end;
		}

		if ( $this->isNegativeNumber( $phpcsFile, $start, $end, true ) !== true ) {
			// Not a negative number or undetermined.
			return;
		}

		$phpcsFile->addError(
			'Bitwise shifts by negative number will throw an ArithmeticError in PHP 7.0. Found: %s',
			$stackPtr,
			'Found',
			array( $phpcsFile->getTokensAsString( $start, ( $end - $start + 1 ) ) )
		);
	}
}
