class UnusedSystemSniff

class UnusedSystemSniff implements Sniff {
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_DOUBLE_COLON,
        ];
    }
    
    //end register()
    
    /**
     * Processes this sniff, 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();
        // Check if this is a call to includeSystem, includeAsset or includeWidget.
        $methodName = strtolower($tokens[$stackPtr + 1]['content']);
        if ($methodName === 'includesystem' || $methodName === 'includeasset' || $methodName === 'includewidget') {
            $systemName = $phpcsFile->findNext(T_WHITESPACE, $stackPtr + 3, null, true);
            if ($systemName === false || $tokens[$systemName]['code'] !== T_CONSTANT_ENCAPSED_STRING) {
                // Must be using a variable instead of a specific system name.
                // We can't accurately check that.
                return;
            }
            $systemName = trim($tokens[$systemName]['content'], " '");
        }
        else {
            return;
        }
        if ($methodName === 'includeasset') {
            $systemName .= 'assettype';
        }
        else {
            if ($methodName === 'includewidget') {
                $systemName .= 'widgettype';
            }
        }
        $systemName = strtolower($systemName);
        // Now check if this system is used anywhere in this scope.
        $level = $tokens[$stackPtr]['level'];
        for ($i = $stackPtr + 1; $i < $phpcsFile->numTokens; $i++) {
            if ($tokens[$i]['level'] < $level) {
                // We have gone out of scope.
                // If the original include was inside an IF statement that
                // is checking if the system exists, check the outer scope
                // as well.
                if ($tokens[$stackPtr]['level'] === $level) {
                    // We are still in the base level, so this is the first
                    // time we have got here.
                    $conditions = array_keys($tokens[$stackPtr]['conditions']);
                    if (empty($conditions) === false) {
                        $cond = array_pop($conditions);
                        if ($tokens[$cond]['code'] === T_IF) {
                            $i = $tokens[$cond]['scope_closer'];
                            $level--;
                            continue;
                        }
                    }
                }
                break;
            }
            
            //end if
            if ($tokens[$i]['code'] !== T_DOUBLE_COLON && $tokens[$i]['code'] !== T_EXTENDS && $tokens[$i]['code'] !== T_IMPLEMENTS) {
                continue;
            }
            switch ($tokens[$i]['code']) {
                case T_DOUBLE_COLON:
                    $usedName = strtolower($tokens[$i - 1]['content']);
                    if ($usedName === $systemName) {
                        // The included system was used, so it is fine.
                        return;
                    }
                    break;
                case T_EXTENDS:
                    $classNameToken = $phpcsFile->findNext(T_STRING, $i + 1);
                    $className = strtolower($tokens[$classNameToken]['content']);
                    if ($className === $systemName) {
                        // The included system was used, so it is fine.
                        return;
                    }
                    break;
                case T_IMPLEMENTS:
                    $endImplements = $phpcsFile->findNext([
                        T_EXTENDS,
                        T_OPEN_CURLY_BRACKET,
                    ], $i + 1);
                    for ($x = $i + 1; $x < $endImplements; $x++) {
                        if ($tokens[$x]['code'] === T_STRING) {
                            $className = strtolower($tokens[$x]['content']);
                            if ($className === $systemName) {
                                // The included system was used, so it is fine.
                                return;
                            }
                        }
                    }
                    break;
            }
            
            //end switch
        }
        
        //end for
        // If we get to here, the system was not use.
        $error = 'Included system "%s" is never used';
        $data = [
            $systemName,
        ];
        $phpcsFile->addError($error, $stackPtr, 'Found', $data);
    }
    
    //end process()

}