class UnnecessaryHeredocSniff

class UnnecessaryHeredocSniff implements Sniff {
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_START_HEREDOC,
        ];
    }
    
    //end register()
    
    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @param \PHP_CodeSniffer\Files\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) {
        $tokens = $phpcsFile->getTokens();
        if (isset($tokens[$stackPtr]['scope_closer']) === false) {
            // Just to be safe. Shouldn't be possible as in that case, the opener shouldn't be tokenized
            // to T_START_HEREDOC by PHP.
            return;
            // @codeCoverageIgnore
        }
        $closer = $tokens[$stackPtr]['scope_closer'];
        $body = '';
        // Collect all the tokens within the heredoc body.
        for ($i = $stackPtr + 1; $i < $closer; $i++) {
            $body .= $tokens[$i]['content'];
        }
        $tokenizedBody = token_get_all(sprintf("<?php <<<EOD\n%s\nEOD;\n?>", $body));
        foreach ($tokenizedBody as $ptr => $bodyToken) {
            if (is_array($bodyToken) === false) {
                continue;
            }
            if ($bodyToken[0] === T_DOLLAR_OPEN_CURLY_BRACES || $bodyToken[0] === T_VARIABLE) {
                // Contains interpolation or expression.
                $phpcsFile->recordMetric($stackPtr, 'Heredoc contains interpolation or expression', 'yes');
                return;
            }
            if ($bodyToken[0] === T_CURLY_OPEN && is_array($tokenizedBody[$ptr + 1]) === false && $tokenizedBody[$ptr + 1] === '$') {
                // Contains interpolation or expression.
                $phpcsFile->recordMetric($stackPtr, 'Heredoc contains interpolation or expression', 'yes');
                return;
            }
        }
        
        //end foreach
        $phpcsFile->recordMetric($stackPtr, 'Heredoc contains interpolation or expression', 'no');
        $warning = 'Detected heredoc without interpolation or expressions. Use nowdoc syntax instead';
        $fix = $phpcsFile->addFixableWarning($warning, $stackPtr, 'Found');
        if ($fix === true) {
            $identifier = trim(ltrim($tokens[$stackPtr]['content'], '<'));
            $replaceWith = "'" . trim($identifier, '"') . "'";
            $replacement = str_replace($identifier, $replaceWith, $tokens[$stackPtr]['content']);
            $phpcsFile->fixer
                ->replaceToken($stackPtr, $replacement);
        }
    }
    
    //end process()

}