class VariableHelper

class VariableHelper {
    public static function isUsedInScope(File $phpcsFile, int $scopeOwnerPointer, int $variablePointer) : bool {
        return self::isUsedInScopeInternal($phpcsFile, $scopeOwnerPointer, $variablePointer, null);
    }
    public static function isUsedInScopeAfterPointer(File $phpcsFile, int $scopeOwnerPointer, int $variablePointer, int $startCheckPointer) : bool {
        return self::isUsedInScopeInternal($phpcsFile, $scopeOwnerPointer, $variablePointer, $startCheckPointer);
    }
    public static function isUsedAsVariable(File $phpcsFile, int $variablePointer, int $variableToCheckPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        if ($tokens[$variablePointer]['content'] !== $tokens[$variableToCheckPointer]['content']) {
            return false;
        }
        if ($tokens[$variableToCheckPointer - 1]['code'] === T_DOUBLE_COLON) {
            $pointerAfterVariable = TokenHelper::findNextEffective($phpcsFile, $variableToCheckPointer + 1);
            return $tokens[$pointerAfterVariable]['code'] === T_OPEN_PARENTHESIS;
        }
        return !ParameterHelper::isParameter($phpcsFile, $variableToCheckPointer);
    }
    public static function isUsedInCompactFunction(File $phpcsFile, int $variablePointer, int $stringPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        $stringContent = $tokens[$stringPointer]['content'];
        if (strtolower($stringContent) !== 'compact') {
            return false;
        }
        $parenthesisOpenerPointer = TokenHelper::findNextEffective($phpcsFile, $stringPointer + 1);
        if ($tokens[$parenthesisOpenerPointer]['code'] !== T_OPEN_PARENTHESIS) {
            return false;
        }
        $variableNameWithoutDollar = substr($tokens[$variablePointer]['content'], 1);
        for ($i = $parenthesisOpenerPointer + 1; $i < $tokens[$parenthesisOpenerPointer]['parenthesis_closer']; $i++) {
            if (preg_match('~^([\'"])' . $variableNameWithoutDollar . '\\1$~', $tokens[$i]['content']) !== 0) {
                return true;
            }
        }
        return false;
    }
    public static function isUsedInScopeInString(File $phpcsFile, string $variableName, int $stringPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        $stringContent = $tokens[$stringPointer]['content'];
        if (preg_match('~(\\\\)?(' . preg_quote($variableName, '~') . ')\\b~', $stringContent, $matches) !== 0) {
            if ($matches[1] === '') {
                return true;
            }
            if (strlen($matches[1]) % 2 === 1) {
                return true;
            }
        }
        $variableNameWithoutDollar = substr($variableName, 1);
        return preg_match('~\\$\\{' . preg_quote($variableNameWithoutDollar, '~') . '(<=\\}|\\b)~', $stringContent) !== 0;
    }
    private static function isUsedInScopeInternal(File $phpcsFile, int $scopeOwnerPointer, int $variablePointer, ?int $startCheckPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        if ($tokens[$scopeOwnerPointer]['code'] === T_OPEN_TAG) {
            $scopeCloserPointer = count($tokens) - 1;
        }
        elseif ($tokens[$scopeOwnerPointer]['code'] === T_FN) {
            $scopeCloserPointer = $tokens[$scopeOwnerPointer]['scope_closer'];
        }
        else {
            $scopeCloserPointer = $tokens[$scopeOwnerPointer]['scope_closer'] - 1;
        }
        if ($tokens[$scopeOwnerPointer]['code'] === T_OPEN_TAG) {
            $firstPointerInScope = $scopeOwnerPointer + 1;
        }
        elseif ($tokens[$scopeOwnerPointer]['code'] === T_FN) {
            $firstPointerInScope = $tokens[$scopeOwnerPointer]['scope_opener'];
        }
        else {
            $firstPointerInScope = $tokens[$scopeOwnerPointer]['scope_opener'] + 1;
        }
        if ($startCheckPointer === null) {
            $startCheckPointer = $firstPointerInScope;
        }
        for ($i = $startCheckPointer; $i <= $scopeCloserPointer; $i++) {
            if (!ScopeHelper::isInSameScope($phpcsFile, $i, $firstPointerInScope)) {
                continue;
            }
            if ($tokens[$i]['code'] === T_VARIABLE && self::isUsedAsVariable($phpcsFile, $variablePointer, $i)) {
                return true;
            }
            if ($tokens[$i]['code'] === T_STRING) {
                if (self::isGetDefinedVarsCall($phpcsFile, $i)) {
                    return true;
                }
                if (self::isUsedInCompactFunction($phpcsFile, $variablePointer, $i)) {
                    return true;
                }
            }
            if (in_array($tokens[$i]['code'], [
                T_DOUBLE_QUOTED_STRING,
                T_HEREDOC,
            ], true) && self::isUsedInScopeInString($phpcsFile, $tokens[$variablePointer]['content'], $i)) {
                return true;
            }
        }
        return false;
    }
    private static function isGetDefinedVarsCall(File $phpcsFile, int $stringPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        $stringContent = $tokens[$stringPointer]['content'];
        if (strtolower($stringContent) !== 'get_defined_vars') {
            return false;
        }
        $parenthesisOpenerPointer = TokenHelper::findNextEffective($phpcsFile, $stringPointer + 1);
        return $tokens[$parenthesisOpenerPointer]['code'] === T_OPEN_PARENTHESIS;
    }

}