class UnusedUseStatementSniff

class UnusedUseStatementSniff implements Sniff {
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_USE,
        ];
    }
    
    //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 = $phpcsFile->getTokens();
        // Only check use statements in the global scope.
        if (empty($tokens[$stackPtr]['conditions']) === false) {
            return;
        }
        // Seek to the end of the statement and get the string before the semi colon.
        $semiColon = $phpcsFile->findEndOfStatement($stackPtr);
        if ($tokens[$semiColon]['code'] !== T_SEMICOLON) {
            return;
        }
        $classPtr = $phpcsFile->findPrevious(Tokens::$emptyTokens, $semiColon - 1, null, true);
        if ($tokens[$classPtr]['code'] !== T_STRING) {
            return;
        }
        // Search where the class name is used. PHP treats class names case
        // insensitive, that's why we cannot search for the exact class name string
        // and need to iterate over all T_STRING tokens in the file.
        $classUsed = $phpcsFile->findNext(T_STRING, $classPtr + 1);
        $lowerClassName = strtolower($tokens[$classPtr]['content']);
        // Check if the referenced class is in the same namespace as the current
        // file. If it is then the use statement is not necessary.
        $namespacePtr = $phpcsFile->findPrevious([
            T_NAMESPACE,
        ], $stackPtr);
        // Check if the use statement does aliasing with the "as" keyword. Aliasing
        // is allowed even in the same namespace.
        $aliasUsed = $phpcsFile->findPrevious(T_AS, $classPtr - 1, $stackPtr);
        if ($namespacePtr !== false && $aliasUsed === false) {
            $nsEnd = $phpcsFile->findNext([
                T_NS_SEPARATOR,
                T_STRING,
                T_WHITESPACE,
            ], $namespacePtr + 1, null, true);
            $namespace = trim($phpcsFile->getTokensAsString($namespacePtr + 1, $nsEnd - $namespacePtr - 1));
            $useNamespacePtr = $phpcsFile->findNext([
                T_STRING,
            ], $stackPtr + 1);
            $useNamespaceEnd = $phpcsFile->findNext([
                T_NS_SEPARATOR,
                T_STRING,
            ], $useNamespacePtr + 1, null, true);
            $useNamespace = rtrim($phpcsFile->getTokensAsString($useNamespacePtr, $useNamespaceEnd - $useNamespacePtr - 1), '\\');
            if (strcasecmp($namespace, $useNamespace) === 0) {
                $classUsed = false;
            }
        }
        
        //end if
        while ($classUsed !== false) {
            if (strtolower($tokens[$classUsed]['content']) === $lowerClassName) {
                // If the name is used in a PHP 7 function return type declaration
                // stop.
                if ($tokens[$classUsed]['code'] === T_RETURN_TYPE) {
                    return;
                }
                $beforeUsage = $phpcsFile->findPrevious(Tokens::$emptyTokens, $classUsed - 1, null, true);
                // If a backslash is used before the class name then this is some other
                // use statement.
                if (in_array($tokens[$beforeUsage]['code'], [
                    T_USE,
                    T_NS_SEPARATOR,
                    // If an object operator is used then this is a method call
                    // with the same name as the class name. Which means this is
                    // not referring to the class.
T_OBJECT_OPERATOR,
                    // Function definition, not class invocation.
T_FUNCTION,
                    // Static method call, not class invocation.
T_DOUBLE_COLON,
                ]) === false) {
                    return;
                }
                // Trait use statement within a class.
                if ($tokens[$beforeUsage]['code'] === T_USE && empty($tokens[$beforeUsage]['conditions']) === false) {
                    return;
                }
            }
            
            //end if
            $classUsed = $phpcsFile->findNext([
                T_STRING,
                T_RETURN_TYPE,
            ], $classUsed + 1);
        }
        
        //end while
        $warning = 'Unused use statement';
        $fix = $phpcsFile->addFixableWarning($warning, $stackPtr, 'UnusedUse');
        if ($fix === true) {
            // Remove the whole use statement line.
            $phpcsFile->fixer
                ->beginChangeset();
            for ($i = $stackPtr; $i <= $semiColon; $i++) {
                $phpcsFile->fixer
                    ->replaceToken($i, '');
            }
            // Also remove whitespace after the semicolon (new lines).
            while (isset($tokens[$i]) === true && $tokens[$i]['code'] === T_WHITESPACE) {
                $phpcsFile->fixer
                    ->replaceToken($i, '');
                if (strpos($tokens[$i]['content'], $phpcsFile->eolChar) !== false) {
                    break;
                }
                $i++;
            }
            // Replace @var data types in doc comments with the fully qualified class
            // name.
            $useNamespacePtr = $phpcsFile->findNext([
                T_STRING,
            ], $stackPtr + 1);
            $useNamespaceEnd = $phpcsFile->findNext([
                T_NS_SEPARATOR,
                T_STRING,
            ], $useNamespacePtr + 1, null, true);
            $fullNamespace = $phpcsFile->getTokensAsString($useNamespacePtr, $useNamespaceEnd - $useNamespacePtr);
            $tag = $phpcsFile->findNext(T_DOC_COMMENT_TAG, $stackPtr + 1);
            while ($tag !== false) {
                if (($tokens[$tag]['content'] === '@var' || $tokens[$tag]['content'] === '@return') && isset($tokens[$tag + 1]) === true && $tokens[$tag + 1]['code'] === T_DOC_COMMENT_WHITESPACE && isset($tokens[$tag + 2]) === true && $tokens[$tag + 2]['code'] === T_DOC_COMMENT_STRING && strpos($tokens[$tag + 2]['content'], $tokens[$classPtr]['content']) === 0) {
                    $replacement = '\\' . $fullNamespace . substr($tokens[$tag + 2]['content'], strlen($tokens[$classPtr]['content']));
                    $phpcsFile->fixer
                        ->replaceToken($tag + 2, $replacement);
                }
                $tag = $phpcsFile->findNext(T_DOC_COMMENT_TAG, $tag + 1);
            }
            $phpcsFile->fixer
                ->endChangeset();
        }
        
        //end if
    }
    
    //end process()

}