<?php
/**
 * \PHPCompatibility\Sniffs\Variables\RemovedPredefinedGlobalVariablesSniff.
 *
 * @category PHP
 * @package  PHPCompatibility
 * @author   Wim Godden <wim.godden@cu.be>
 */

namespace PHPCompatibility\Sniffs\Variables;

use PHPCompatibility\AbstractRemovedFeatureSniff;
use PHPCompatibility\PHPCSHelper;
use PHP_CodeSniffer_File as File;
use PHP_CodeSniffer_Tokens as Tokens;

/**
 * \PHPCompatibility\Sniffs\Variables\RemovedPredefinedGlobalVariablesSniff.
 *
 * Discourages the use of removed global variables. Suggests alternative extensions if available
 *
 * @category PHP
 * @package  PHPCompatibility
 * @author   Wim Godden <wim.godden@cu.be>
 */
class RemovedPredefinedGlobalVariablesSniff extends AbstractRemovedFeatureSniff
{

    /**
     * A list of removed global variables with their alternative, if any.
     *
     * The array lists : version number with false (deprecated) and true (removed).
     * If's sufficient to list the first version where the variable was deprecated/removed.
     *
     * @var array(string|null)
     */
    protected $removedGlobalVariables = array(
        'HTTP_POST_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_POST',
        ),
        'HTTP_GET_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_GET',
        ),
        'HTTP_ENV_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_ENV',
        ),
        'HTTP_SERVER_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_SERVER',
        ),
        'HTTP_COOKIE_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_COOKIE',
        ),
        'HTTP_SESSION_VARS' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_SESSION',
        ),
        'HTTP_POST_FILES' => array(
            '5.3' => false,
            '5.4' => true,
            'alternative' => '$_FILES',
        ),

        'HTTP_RAW_POST_DATA' => array(
            '5.6' => false,
            '7.0' => true,
            'alternative' => 'php://input',
        ),

        'php_errormsg' => array(
            '7.2' => false,
            'alternative' => 'error_get_last()',
        ),
    );


    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array
     */
    public function register()
    {
        return array(\T_VARIABLE);
    }


    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @param \PHP_CodeSniffer_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, $stackPtr)
    {
        if ($this->supportsAbove('5.3') === false) {
            return;
        }

        $tokens  = $phpcsFile->getTokens();
        $varName = substr($tokens[$stackPtr]['content'], 1);

        if (isset($this->removedGlobalVariables[$varName]) === false) {
            return;
        }

        if ($this->isClassProperty($phpcsFile, $stackPtr) === true) {
            // Ok, so this was a class property declaration, not our concern.
            return;
        }

        // Check for static usage of class properties shadowing the removed global variables.
        if ($this->inClassScope($phpcsFile, $stackPtr, false) === true) {
            $prevToken = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true, null, true);
            if ($prevToken !== false && $tokens[$prevToken]['code'] === \T_DOUBLE_COLON) {
                return;
            }
        }

        // Do some additional checks for the $php_errormsg variable.
        if ($varName === 'php_errormsg'
            && $this->isTargetPHPErrormsgVar($phpcsFile, $stackPtr, $tokens) === false
        ) {
            return;
        }

        // Still here, so throw an error/warning.
        $itemInfo = array(
            'name' => $varName,
        );
        $this->handleFeature($phpcsFile, $stackPtr, $itemInfo);
    }


    /**
     * Get the relevant sub-array for a specific item from a multi-dimensional array.
     *
     * @param array $itemInfo Base information about the item.
     *
     * @return array Version and other information about the item.
     */
    public function getItemArray(array $itemInfo)
    {
        return $this->removedGlobalVariables[$itemInfo['name']];
    }


    /**
     * Get the error message template for this sniff.
     *
     * @return string
     */
    protected function getErrorMsgTemplate()
    {
        return "Global variable '\$%s' is ";
    }


    /**
     * Filter the error message before it's passed to PHPCS.
     *
     * @param string $error     The error message which was created.
     * @param array  $itemInfo  Base information about the item this error message applies to.
     * @param array  $errorInfo Detail information about an item this error message applies to.
     *
     * @return string
     */
    protected function filterErrorMsg($error, array $itemInfo, array $errorInfo)
    {
        if ($itemInfo['name'] === 'php_errormsg') {
            $error = str_replace('Global', 'The', $error);
        }
        return $error;
    }

    /**
     * Run some additional checks for the `$php_errormsg` variable.
     *
     * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned.
     * @param int                   $stackPtr  The position of the current token in the
     *                                         stack passed in $tokens.
     * @param array                 $tokens    Token array of the current file.
     *
     * @return bool
     */
    private function isTargetPHPErrormsgVar(File $phpcsFile, $stackPtr, array $tokens)
    {
        $scopeStart = 0;

        /*
         * If the variable is detected within the scope of a function/closure, limit the checking.
         */
        $function = $phpcsFile->getCondition($stackPtr, \T_CLOSURE);
        if ($function === false) {
            $function = $phpcsFile->getCondition($stackPtr, \T_FUNCTION);
        }

        // It could also be a function param, which is not in the function scope.
        if ($function === false && isset($tokens[$stackPtr]['nested_parenthesis']) === true) {
            $nestedParentheses = $tokens[$stackPtr]['nested_parenthesis'];
            $parenthesisCloser = end($nestedParentheses);
            if (isset($tokens[$parenthesisCloser]['parenthesis_owner'])
                && ($tokens[$tokens[$parenthesisCloser]['parenthesis_owner']]['code'] === \T_FUNCTION
                    || $tokens[$tokens[$parenthesisCloser]['parenthesis_owner']]['code'] === \T_CLOSURE)
            ) {
                $function = $tokens[$parenthesisCloser]['parenthesis_owner'];
            }
        }

        if ($function !== false) {
            $scopeStart = $tokens[$function]['scope_opener'];
        }

        /*
         * Now, let's do some additional checks.
         */
        $nextNonEmpty = $phpcsFile->findNext(Tokens::$emptyTokens, ($stackPtr + 1), null, true);

        // Is the variable being used as an array ?
        if ($nextNonEmpty !== false && $tokens[$nextNonEmpty]['code'] === \T_OPEN_SQUARE_BRACKET) {
            // The PHP native variable is a string, so this is probably not it
            // (except for array access to string, but why would you in this case ?).
            return false;
        }

        // Is this a variable assignment ?
        if ($nextNonEmpty !== false
            && isset(Tokens::$assignmentTokens[$tokens[$nextNonEmpty]['code']]) === true
        ) {
            return false;
        }

        // Is this a function param shadowing the PHP native one ?
        if ($function !== false) {
            $parameters = PHPCSHelper::getMethodParameters($phpcsFile, $function);
            if (\is_array($parameters) === true && empty($parameters) === false) {
                foreach ($parameters as $param) {
                    if ($param['name'] === '$php_errormsg') {
                        return false;
                    }
                }
            }
        }

        $skipPast = array(
            'T_CLASS'      => true,
            'T_ANON_CLASS' => true,
            'T_INTERFACE'  => true,
            'T_TRAIT'      => true,
            'T_FUNCTION'   => true,
            'T_CLOSURE'    => true,
        );

        // Walk back and see if there is an assignment to the variable within the same scope.
        for ($i = ($stackPtr - 1); $i >= $scopeStart; $i--) {
            if ($tokens[$i]['code'] === \T_CLOSE_CURLY_BRACKET
                && isset($tokens[$i]['scope_condition'])
                && isset($skipPast[$tokens[$tokens[$i]['scope_condition']]['type']])
            ) {
                // Skip past functions, classes etc.
                $i = $tokens[$i]['scope_condition'];
                continue;
            }

            if ($tokens[$i]['code'] !== \T_VARIABLE || $tokens[$i]['content'] !== '$php_errormsg') {
                continue;
            }

            $nextNonEmpty = $phpcsFile->findNext(Tokens::$emptyTokens, ($i + 1), null, true);

            if ($nextNonEmpty !== false
                && isset(Tokens::$assignmentTokens[$tokens[$nextNonEmpty]['code']]) === true
            ) {
                return false;
            }
        }

        return true;
    }
}
