class UnusedFunctionParameterSniff

class UnusedFunctionParameterSniff implements Sniff {
    
    /**
     * The list of class type hints which will be ignored.
     *
     * @var array
     */
    public $ignoreTypeHints = [];
    
    /**
     * A list of all PHP magic methods with fixed method signatures.
     *
     * Note: `__construct()` and `__invoke()` are excluded on purpose
     * as their method signature is not fixed.
     *
     * @var array
     */
    private $magicMethods = [
        '__destruct' => true,
        '__call' => true,
        '__callstatic' => true,
        '__get' => true,
        '__set' => true,
        '__isset' => true,
        '__unset' => true,
        '__sleep' => true,
        '__wakeup' => true,
        '__serialize' => true,
        '__unserialize' => true,
        '__tostring' => true,
        '__set_state' => true,
        '__clone' => true,
        '__debuginfo' => true,
    ];
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_FUNCTION,
            T_CLOSURE,
            T_FN,
        ];
    }
    
    //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();
        $token = $tokens[$stackPtr];
        // Skip broken function declarations.
        if (isset($token['scope_opener']) === false || isset($token['parenthesis_opener']) === false) {
            return;
        }
        $errorCode = 'Found';
        $implements = false;
        if ($token['code'] === T_FUNCTION) {
            $classPtr = $phpcsFile->getCondition($stackPtr, T_CLASS);
            if ($classPtr !== false) {
                // Check for magic methods and ignore these as the method signature cannot be changed.
                $methodName = $phpcsFile->getDeclarationName($stackPtr);
                if (empty($methodName) === false) {
                    $methodNameLc = strtolower($methodName);
                    if (isset($this->magicMethods[$methodNameLc]) === true) {
                        return;
                    }
                }
                // Check for extends/implements and adjust the error code when found.
                $implements = $phpcsFile->findImplementedInterfaceNames($classPtr);
                $extends = $phpcsFile->findExtendedClassName($classPtr);
                if ($extends !== false) {
                    $errorCode .= 'InExtendedClass';
                }
                else {
                    if ($implements !== false) {
                        $errorCode .= 'InImplementedInterface';
                    }
                }
            }
        }
        
        //end if
        $params = [];
        $methodParams = $phpcsFile->getMethodParameters($stackPtr);
        // Skip when no parameters found.
        $methodParamsCount = count($methodParams);
        if ($methodParamsCount === 0) {
            return;
        }
        foreach ($methodParams as $param) {
            if (isset($param['property_visibility']) === true) {
                // Ignore constructor property promotion.
                continue;
            }
            $params[$param['name']] = $stackPtr;
        }
        $next = ++$token['scope_opener'];
        $end = --$token['scope_closer'];
        // Check the end token for arrow functions as
        // they can end at a content token due to not having
        // a clearly defined closing token.
        if ($token['code'] === T_FN) {
            ++$end;
        }
        $foundContent = false;
        $validTokens = [
            T_HEREDOC => T_HEREDOC,
            T_NOWDOC => T_NOWDOC,
            T_END_HEREDOC => T_END_HEREDOC,
            T_END_NOWDOC => T_END_NOWDOC,
            T_DOUBLE_QUOTED_STRING => T_DOUBLE_QUOTED_STRING,
        ];
        $validTokens += Tokens::$emptyTokens;
        for (; $next <= $end; ++$next) {
            $token = $tokens[$next];
            $code = $token['code'];
            // Ignorable tokens.
            if (isset(Tokens::$emptyTokens[$code]) === true) {
                continue;
            }
            if ($foundContent === false) {
                // A throw statement as the first content indicates an interface method.
                if ($code === T_THROW && $implements !== false) {
                    return;
                }
                // A return statement as the first content indicates an interface method.
                if ($code === T_RETURN) {
                    $firstNonEmptyTokenAfterReturn = $phpcsFile->findNext(Tokens::$emptyTokens, $next + 1, null, true);
                    if ($tokens[$firstNonEmptyTokenAfterReturn]['code'] === T_SEMICOLON && $implements !== false) {
                        return;
                    }
                    $secondNonEmptyTokenAfterReturn = $phpcsFile->findNext(Tokens::$emptyTokens, $firstNonEmptyTokenAfterReturn + 1, null, true);
                    if ($secondNonEmptyTokenAfterReturn !== false && $tokens[$secondNonEmptyTokenAfterReturn]['code'] === T_SEMICOLON && $implements !== false) {
                        // There is a return <token>.
                        return;
                    }
                }
                
                //end if
            }
            
            //end if
            $foundContent = true;
            if ($code === T_VARIABLE && isset($params[$token['content']]) === true) {
                unset($params[$token['content']]);
            }
            else {
                if ($code === T_DOLLAR) {
                    $nextToken = $phpcsFile->findNext(T_WHITESPACE, $next + 1, null, true);
                    if ($tokens[$nextToken]['code'] === T_OPEN_CURLY_BRACKET) {
                        $nextToken = $phpcsFile->findNext(T_WHITESPACE, $nextToken + 1, null, true);
                        if ($tokens[$nextToken]['code'] === T_STRING) {
                            $varContent = '$' . $tokens[$nextToken]['content'];
                            if (isset($params[$varContent]) === true) {
                                unset($params[$varContent]);
                            }
                        }
                    }
                }
                else {
                    if ($code === T_DOUBLE_QUOTED_STRING || $code === T_START_HEREDOC || $code === T_START_NOWDOC) {
                        // Tokenize strings that can contain variables.
                        // Make sure the string is re-joined if it occurs over multiple lines.
                        $content = $token['content'];
                        for ($i = $next + 1; $i <= $end; $i++) {
                            if (isset($validTokens[$tokens[$i]['code']]) === true) {
                                $content .= $tokens[$i]['content'];
                                $next++;
                            }
                            else {
                                break;
                            }
                        }
                        $stringTokens = token_get_all(sprintf('<?php %s;?>', $content));
                        foreach ($stringTokens as $stringPtr => $stringToken) {
                            if (is_array($stringToken) === false) {
                                continue;
                            }
                            $varContent = '';
                            if ($stringToken[0] === T_DOLLAR_OPEN_CURLY_BRACES) {
                                $varContent = '$' . $stringTokens[$stringPtr + 1][1];
                            }
                            else {
                                if ($stringToken[0] === T_VARIABLE) {
                                    $varContent = $stringToken[1];
                                }
                            }
                            if ($varContent !== '' && isset($params[$varContent]) === true) {
                                unset($params[$varContent]);
                            }
                        }
                    }
                }
            }
            
            //end if
        }
        
        //end for
        if ($foundContent === true && count($params) > 0) {
            $error = 'The method parameter %s is never used';
            // If there is only one parameter and it is unused, no need for additional errorcode toggling logic.
            if ($methodParamsCount === 1) {
                foreach ($params as $paramName => $position) {
                    if (in_array($methodParams[0]['type_hint'], $this->ignoreTypeHints, true) === true) {
                        continue;
                    }
                    $data = [
                        $paramName,
                    ];
                    $phpcsFile->addWarning($error, $position, $errorCode, $data);
                }
                return;
            }
            $foundLastUsed = false;
            $lastIndex = $methodParamsCount - 1;
            $errorInfo = [];
            for ($i = $lastIndex; $i >= 0; --$i) {
                if ($foundLastUsed !== false) {
                    if (isset($params[$methodParams[$i]['name']]) === true) {
                        $errorInfo[$methodParams[$i]['name']] = [
                            'position' => $params[$methodParams[$i]['name']],
                            'errorcode' => $errorCode . 'BeforeLastUsed',
                            'typehint' => $methodParams[$i]['type_hint'],
                        ];
                    }
                }
                else {
                    if (isset($params[$methodParams[$i]['name']]) === false) {
                        $foundLastUsed = true;
                    }
                    else {
                        $errorInfo[$methodParams[$i]['name']] = [
                            'position' => $params[$methodParams[$i]['name']],
                            'errorcode' => $errorCode . 'AfterLastUsed',
                            'typehint' => $methodParams[$i]['type_hint'],
                        ];
                    }
                }
            }
            
            //end for
            if (count($errorInfo) > 0) {
                $errorInfo = array_reverse($errorInfo);
                foreach ($errorInfo as $paramName => $info) {
                    if (in_array($info['typehint'], $this->ignoreTypeHints, true) === true) {
                        continue;
                    }
                    $data = [
                        $paramName,
                    ];
                    $phpcsFile->addWarning($error, $info['position'], $info['errorcode'], $data);
                }
            }
        }
        
        //end if
    }
    
    //end process()

}