<?php
/** ****************************************************************************************************************************
 * This script will check the compatibility of all software and hardware components for the installation of the CRM system.
 * 
*/ 

require_once("config.inc.php");

    $data = systemRequirementsCheck();
    $dbConnectionStatus = checkDbConnection($dbconfig['db_type'], $dbconfig['db_server'], $dbconfig['db_username'], $dbconfig['db_password'], $dbconfig['db_name']);
    if($dbConnectionStatus['flag']) {
        $dbSettingsStatus = checkMySqlConfig($dbconfig['db_type'], $dbconfig['db_server'], $dbconfig['db_username'], $dbconfig['db_password']);
        $dbVersion = dbVersion($dbconfig['db_type'], $dbconfig['db_server'], $dbconfig['db_username'], $dbconfig['db_password']);
    }
    $pathPrivileges = fileSystemPrivileges();
    showDataOnDisplay($data, $dbConnectionStatus, $pathPrivileges, $dbSettingsStatus, $dbVersion);

// ****** Required PHP Configuration ***************************************************************************************************

/**
 * Checks the system requirements needed for installation and returns the results.
 *
 * This function gathers various system settings and configurations, such as current 
 * PHP directive values, recommended settings, and pre-installation parameters, to 
 * ensure the environment meets the necessary requirements.
 *
 * @return array Returns an associative array with the following keys:
 *               - 'directiveValues': Current values of PHP directives on the server.
 *               - 'recommendedDirectives': Recommended values for optimal performance.
 *               - 'preInstallConfig': System parameters required for installation.
 */
function systemRequirementsCheck() {
    $systemRequirementData = array();
    $systemRequirementData['directiveValues'] = getCurrentDirectiveValue();
    $systemRequirementData['recommendedDirectives'] = getRecommendedDirectives();
    $systemRequirementData['preInstallConfig'] = getSystemPreInstallParameters();
    return $systemRequirementData;
}

/**
 * Retrieves current PHP directive values for key settings.
 *
 * This function collects the current configuration values for specific PHP directives, 
 * formatting them in a way that makes it easy to check against recommended settings.
 *
 * @return array Returns an associative array of current PHP directive values, including:
 *               - 'file_uploads': Whether file uploads are enabled ('On' or 'Off').
 *               - 'output_buffering': Whether output buffering is enabled ('On' or 'Off').
 *               - 'max_execution_time': Maximum execution time for scripts, in seconds.
 *               - 'memory_limit': Memory limit for scripts, in bytes.
 *               - 'short_open_tag': Whether short open tags are allowed ('On' or 'Off').
 *               - 'max_input_vars': Maximum number of input variables accepted.
 */
function getCurrentDirectiveValue() {
    $directiveValues = array();
    $fileUploads = ini_get('file_uploads');
    $directiveValues['file_uploads'] = $fileUploads == '1' || stripos($fileUploads, 'On') !== false ? 'On' : 'Off';
    $outputBuffering = ini_get('output_buffering');
    $directiveValues['output_buffering'] = ($outputBuffering >= 4096 || stripos($outputBuffering, 'On') !== false) ? 'On' : 'Off';
    $directiveValues['max_execution_time'] = ini_get('max_execution_time');
    $directiveValues['memory_limit'] = memoryLimitInBytes() < 536870912 ? ini_get('memory_limit') : ini_get('memory_limit');
    $shortOpenTag = ini_get('short_open_tag');
    $directiveValues['short_open_tag'] = $shortOpenTag == '1' || stripos($shortOpenTag, 'On') !== false ? 'On' : 'Off';
    $directiveValues['max_input_vars'] = ini_get('max_input_vars');
    return $directiveValues;
}

/**
 * Converts the PHP memory limit setting to bytes.
 *
 * This function retrieves the memory limit from the PHP configuration and converts
 * it to an integer value in bytes. It handles suffixes like 'M' (megabytes), 
 * 'K' (kilobytes), and 'G' (gigabytes).
 *
 * @return int The memory limit in bytes as an integer. Returns the original value if no suffix is present.
 */
function memoryLimitInBytes() {
    $s = ini_get('memory_limit');
    switch (substr ($s, -1)) {
        case 'M': case 'm': return (int)$s * 1048576;
        case 'K': case 'k': return (int)$s * 1024;
        case 'G': case 'g': return (int)$s * 1073741824;
        default: return $s;
    }
}


/**
 * Converts the PHP memory limit setting to bytes.
 *
 * @return int The memory limit in bytes.
 */
function getRecommendedDirectives() {
    $recommendedDirectives = array (
        'file_uploads' => 'On',
        'output_buffering' => 'On',
        'max_execution_time' => '3600',
        'memory_limit' => '512M',
        'short_open_tag' => 'Off',
        'max_input_vars' => 8192
    );
    if(version_compare(PHP_VERSION, '5.5.0') >= 0){
        $recommendedDirectives['error_reporting'] = 'E_WARNING & ~E_NOTICE & ~E_DEPRECATED & ~E_STRICT';
    }
    else if(version_compare(PHP_VERSION, '5.3.0') >= 0) {
        $recommendedDirectives['error_reporting'] = 'E_WARNING & ~E_NOTICE & ~E_DEPRECATED';
    }
    return $recommendedDirectives;
}

// ****** Required PHP Extensions ***************************************************************************************************

/**
 * Checks the system requirements for vtigerCRM installation.
 *
 * This function collects and verifies the system's configuration parameters, 
 * ensuring compatibility with vtigerCRM's installation prerequisites.
 * It checks PHP version, web server type and version, operating system, 
 * SSL configuration, and several PHP extensions.
 *
 * @return array An associative array where each key is a requirement, and its value is an array 
 *               containing the system's current value, the recommended value, and whether the 
 *               requirement is met (true/false).
 */
function getSystemPreInstallParameters() {
    $gdInfoAlternate = 'function gd_info() {
        $array = Array(
                    "GD Version" => "",
                    "FreeType Support" => 0,
                    "FreeType Support" => 0,
                    "FreeType Linkage" => "",
                    "T1Lib Support" => 0,
                    "GIF Read Support" => 0,
                    "GIF Create Support" => 0,
                    "JPG Support" => 0,
                    "PNG Support" => 0,
                    "WBMP Support" => 0,
                    "XBM Support" => 0
                    );
                $gif_support = 0;

                ob_start();
                eval("phpinfo();");
                $info = ob_get_contents();
                ob_end_clean();

                foreach(explode("\n", $info) as $line) {
                    if(strpos($line, "GD Version")!==false)
                        $array["GD Version"] = trim(str_replace("GD Version", "", strip_tags($line)));
                    if(strpos($line, "FreeType Support")!==false)
                        $array["FreeType Support"] = trim(str_replace("FreeType Support", "", strip_tags($line)));
                    if(strpos($line, "FreeType Linkage")!==false)
                        $array["FreeType Linkage"] = trim(str_replace("FreeType Linkage", "", strip_tags($line)));
                    if(strpos($line, "T1Lib Support")!==false)
                        $array["T1Lib Support"] = trim(str_replace("T1Lib Support", "", strip_tags($line)));
                    if(strpos($line, "GIF Read Support")!==false)
                        $array["GIF Read Support"] = trim(str_replace("GIF Read Support", "", strip_tags($line)));
                    if(strpos($line, "GIF Create Support")!==false)
                        $array["GIF Create Support"] = trim(str_replace("GIF Create Support", "", strip_tags($line)));
                    if(strpos($line, "GIF Support")!==false)
                        $gif_support = trim(str_replace("GIF Support", "", strip_tags($line)));
                    if(strpos($line, "JPG Support")!==false)
                        $array["JPG Support"] = trim(str_replace("JPG Support", "", strip_tags($line)));
                    if(strpos($line, "PNG Support")!==false)
                        $array["PNG Support"] = trim(str_replace("PNG Support", "", strip_tags($line)));
                    if(strpos($line, "WBMP Support")!==false)
                        $array["WBMP Support"] = trim(str_replace("WBMP Support", "", strip_tags($line)));
                    if(strpos($line, "XBM Support")!==false)
                        $array["XBM Support"] = trim(str_replace("XBM Support", "", strip_tags($line)));
                }

                if($gif_support==="enabled") {
                    $array["GIF Read Support"]  = 1;
                    $array["GIF Create Support"] = 1;
                }

                if($array["FreeType Support"]==="enabled"){
                    $array["FreeType Support"] = 1;    }

                if($array["T1Lib Support"]==="enabled")
                    $array["T1Lib Support"] = 1;

                if($array["GIF Read Support"]==="enabled"){
                    $array["GIF Read Support"] = 1;    }

                if($array["GIF Create Support"]==="enabled")
                    $array["GIF Create Support"] = 1;

                if($array["JPG Support"]==="enabled")
                    $array["JPG Support"] = 1;

                if($array["PNG Support"]==="enabled")
                    $array["PNG Support"] = 1;

                if($array["WBMP Support"]==="enabled")
                    $array["WBMP Support"] = 1;

                if($array["XBM Support"]==="enabled")
                    $array["XBM Support"] = 1;

                return $array;
        }';

    $phpVersion = '7.4.0';
    $preInstallConfig = array();
    // Name => array( System Value, Recommended value, supported or not(true/false) );
    $preInstallConfig['PHP Version']            = array(phpversion(), $phpVersion, (version_compare(phpversion(), $phpVersion, '>=')));
    if(!empty(shell_exec('apache2 -v'))) {
        $preInstallConfig['Apache-Version']     = array(getCleanedVersion(shell_exec('apache2 -v')), '2.0.40',(version_compare(getCleanedVersion(shell_exec('apache2 -v')), '2.0.40', '>=')));
    }
    elseif(!empty(shell_exec('httpd -v'))) {
        $preInstallConfig['Apache-Version']     = array(getCleanedVersion(shell_exec('httpd -v')), '2.0.40',(version_compare(getCleanedVersion(shell_exec('httpd -v')), '2.0.40', '>=')));
    }
    elseif(!empty(shell_exec('nginx -v 2>&1'))) {
        $preInstallConfig['Nginx-Version']      = array(getCleanedVersion(shell_exec('nginx -v 2>&1')), '1.13',(version_compare(getCleanedVersion(shell_exec('nginx -v 2>&1')), '1.13', '>=')));
    }
    $preInstallConfig['OS']                     = array(php_uname(), array("Debian", "Centos", "Ubuntu","Fedora Core"),isSupportedOS(php_uname()));
    $preInstallConfig['SSL']                    = array($_SERVER['HTTPS'], "On",isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? true : false);
    if($preInstallConfig['SSL'][2] === false) {
        if (isset($_SERVER['HTTP_X_FORWARDED_HOST']) && ($_SERVER['HTTP_X_FORWARDED_HOST'] !='')) {
            $preInstallConfig['SSL'][3] = '(might be ok, since site is behind proxy for host: '.$_SERVER['HTTP_X_FORWARDED_HOST'].")";
        }
    } 

    $preInstallConfig['Imap Support']       = array(function_exists('imap_open'), true, (function_exists('imap_open') == true));
    $preInstallConfig['Zlib Support']       = array(function_exists('gzinflate'), true, (function_exists('gzinflate') == true));

    if ($preInstallConfig['PHP Version'] >= $phpVersion) {
        $preInstallConfig['mysqli support'] = array(extension_loaded('mysqli'), true, extension_loaded('mysqli'));
    }
    $preInstallConfig['openssl support']    = array(extension_loaded('openssl'), true, extension_loaded('openssl'));
    $preInstallConfig['cURL support']       = array(extension_loaded('curl'), true, extension_loaded('curl'));
    $preInstallConfig['xml']                = array(extension_loaded('xml'), true, extension_loaded('xml'));
    $preInstallConfig['mbstring']           = array(extension_loaded('mbstring'), true, extension_loaded('mbstring'));
    $preInstallConfig['opcache']            = array((is_array(opcache_get_status()) ? true : false), true, (is_array(opcache_get_status()) ? true : false));
    $preInstallConfig['ctype']              = array(extension_loaded('ctype'), true, extension_loaded('ctype'));
    $preInstallConfig['simplexml']          = array(extension_loaded('simplexml'), true, extension_loaded('simplexml'));
    $preInstallConfig['zip']                = array(extension_loaded('zip'), true, extension_loaded('zip'));
    $preInstallConfig['session']            = array(extension_loaded('session'), true, extension_loaded('session'));
    $preInstallConfig['bcmath']             = array(extension_loaded('bcmath'), true, extension_loaded('bcmath'));
    $gnInstalled = false;
    if(!function_exists('gd_info')) {
        eval($gdInfoAlternate);
    }
    $gd_info = gd_info();
    if (isset($gd_info['GD Version'])) {
        $gnInstalled = true;
    }
    $preInstallConfig['GD Library Support'] = array((extension_loaded('gd') || $gnInstalled), true, (extension_loaded('gd') || $gnInstalled));
    return $preInstallConfig;
}

/**
 * Extracts and cleans the version number from command output.
 *
 * @param string $output The raw output from a version command.
 * @return string The cleaned version number or an error message if not found.
 */
function getCleanedVersion($output) {
    $parts = explode(" ", $output);
    foreach ($parts as $part) {
        $cleaned = filter_var($part, FILTER_SANITIZE_NUMBER_FLOAT, FILTER_FLAG_ALLOW_FRACTION);
        if ($cleaned && strpos($cleaned, '.') !== false) {
            return $cleaned;
        }
    }
    return 'Version nicht gefunden';
}

/**
 * Checks if the provided OS details match any supported operating systems.
 *
 * @param string $osDetails The operating system details to check.
 * @return string|bool The name of the supported OS if found, otherwise false.
 */
function isSupportedOS($osDetails) {
    $supportedOS = ['Debian', 'CentOS', 'Ubuntu', 'Fedora'];
    foreach ($supportedOS as $os) {
        if (stripos($osDetails, $os) !== false) {
            return $os;
        }
    }
    return false;
}

// ****** MYSQL Requirements ***************************************************************************************************


/**
 * Function checks the database connection
 * @param <String> $db_type
 * @param <String> $db_hostname
 * @param <String> $db_username
 * @param <String> $db_password
 * @param <String> $db_name
 * @return <Array>
 */
function checkDbConnection($db_type, $db_hostname, $db_username, $db_password, $db_name) {
    require('libraries/adodb/adodb.inc.php');
    $dbCheckResult = array();

    $db_type_status = false; // is there a db type?
    $db_server_status = false; // does the db server connection exist?
    $db_creation_failed = false; // did we try to create a database and fail?
    $db_exist_status = false; // does the database exist?
    $db_utf8_support = false; // does the database support utf8?

    //Checking for database connection parameters
    if($db_type) {
        $conn = NewADOConnection($db_type);
        $db_type_status = true;
        if(@$conn->Connect($db_hostname,$db_username,$db_password)) {
            $db_server_status = true;
            $serverInfo = $conn->ServerInfo();
            if(isMySQL($db_type)) {
                $mysql_server_version = getMySQLVersion($serverInfo);
            }

            if(@$conn->Connect($db_hostname, $db_username, $db_password, $db_name)) {
                $db_exist_status = true;
                if(!$db_utf8_support) {
                    $db_utf8_support = checkDbUTF8Support($conn);
                }
            }
            $conn->Close();
        }
    }
    $dbCheckResult['db_utf8_support'] = $db_utf8_support;

    $error_msg = '';
    $error_msg_info = '';
    if(!$db_type_status || !$db_server_status) {
        $error_msg = 'Unable to connect to database Server. Invalid mySQL Connection Parameters specified';
        $error_msg_info = 'This may be due to the following reasons:<br>'.'
                -  specified database user, password, hostname, database type, or port is invalid<br>
                -  specified database user does not have access to connect to the database server from the host';
    } elseif(isMySQL($db_type) && !strpos($serverInfo['description'], "MariaDB") && !strpos($serverInfo['description'], "MariaDB")) {
        $error_msg = $mysql_server_version.' -> You are not using MySQL as recommended, kindly switch to MySQL';
    } elseif(isMySQL($db_type) && strpos($serverInfo['description'], "MariaDB") !== false && (intval($mysql_server_version) < 10)) {
        $error_msg = $mysql_server_version.' -> MariaDB version is not supported, kindly connect to MySQL 10.x.x or above';
    } elseif(isMySQL($db_type) && strpos($serverInfo['description'], "mysql") && intval($mysql_server_version) < 5.5) {
        $error_msg = $mysql_server_version.' -> MySQL version is not supported, kindly connect to MySQL 5.1.x or above';
    } elseif($db_creation_failed) {
        $error_msg = 'Unable to Create database';
        $error_msg_info = 'Message: Specified database Root User doesn\'t have permission to Create database or the Database name has special characters. Try changing the Database settings';
    } elseif(!$db_exist_status) {
        $error_msg = $db_name.' -> This Database is not found.Try changing the Database settings';
    } else {
        $dbCheckResult['flag'] = true;
        return $dbCheckResult;
    }
    $dbCheckResult['flag'] = false;
    $dbCheckResult['error_msg'] = $error_msg;
    $dbCheckResult['error_msg_info'] = $error_msg_info;
    return $dbCheckResult;
}

/**
 * Function checks if its mysql type
 * @param type $dbType
 * @return type
 */
function isMySQL($dbType) {
    return (stripos(strval($dbType) ,'mysql') === 0);
}

/**
 * Retrieves the MySQL version from server information.
 *
 * @param mixed $serverInfo The server information, can be an array or a string.
 * @return string The MySQL server version.
 */
function getMySQLVersion($serverInfo) {
    if(!is_array($serverInfo)) {
        $version = explode('-',strval($serverInfo));
        $mysql_server_version=$version[0];
    } else {
        $mysql_server_version = $serverInfo['version'];
    }
    return $mysql_server_version;
}

/**
 * Checks if the connected database supports UTF-8 character set.
 *
 * @param object $conn Database connection object.
 * @return bool True if UTF-8 is supported, false otherwise.
 */
function checkDbUTF8Support($conn) {
    global $db_type;
    if($db_type == 'pgsql')
        return true;
    $dbvarRS = $conn->Execute("show variables like '%_database' ");
    $db_character_set = null;
    $db_collation_type = null;
    while(!$dbvarRS->EOF) {
        $arr = $dbvarRS->FetchRow();
        $arr = array_change_key_case($arr);
        switch($arr['variable_name']) {
            case 'character_set_database' : $db_character_set = $arr['value']; break;
            case 'collation_database'     : $db_collation_type = $arr['value']; break;
        }
        // If we have all the required information break the loop. 
        if($db_character_set != null && $db_collation_type != null) break;
    }
    return (stristr($db_character_set, 'utf8') && stristr($db_collation_type, 'utf8'));
}

/**
 * Checks MySQL configuration settings for compatibility and best practices.
 *
 * @param string $db_type Database type (e.g., 'mysqli', 'pdo_mysql').
 * @param string $db_host Database host (e.g., 'localhost').
 * @param string $db_user Database username.
 * @param string $db_password Database password.
 * @return mixed Returns true if all checks pass; otherwise returns an array of error messages or false on connection failure.
 */
function checkMySqlConfig($db_type, $db_host, $db_user, $db_password) {
    require('libraries/adodb/adodb.inc.php');
    $conn = NewADOConnection($db_type);
    if(@$conn->Connect($db_host, $db_user, $db_password)) {
        //Check SqlMode
        $res = $conn->query("SELECT @@GLOBAL.sql_mode");
        $sqlMode = $res->fields[0];
        $err_report = array();
        $errSqlMode = true;
        if(strpos($sqlMode, 'STRICT_TRANS_TABLE') !== false) {
            $err_report['STRICT_TRANS_TABLE'] = array("Setting 'STRICT_TRANS_TABLE' should be deactivated", "active");
            $errSqlMode = false;
        }
        if(strpos($sqlMode, 'IGNORE_SPACE') === false) {
            $err_report['IGNORE_SPACE'] = array("Setting 'IGNORE_SPACE' is missing");
            $errSqlMode = false;
        }
        if(strpos($sqlMode, 'NO_AUTO_CREATE_USER') === false) {
            $err_report['NO_AUTO_CREATE_USER'] = array("Setting 'NO_AUTO_CREATE_USER' is missing");
            $errSqlMode = false;
        }
        if(strpos($sqlMode, 'NO_ENGINE_SUBSTITUTION') === false) {
            $err_report['NO_ENGINE_SUBSTITUTION'] = array("Setting 'NO_ENGINE_SUBSTITUTION' is missing");
            $errSqlMode = false;
        }

        //Check InnoDB active
        $res = $conn->query("SHOW ENGINES");
        $errInnodbActive = false;
        while (!$res->EOF) {
            if ($res->fields['Engine'] === 'InnoDB' && (strtolower($res->fields['Support']) === 'yes' || strtolower($res->fields['Support']) === "default")) {
                $errInnodbActive = true;
                break;
            }
            $res->MoveNext();
        }
        if($errInnodbActive === false) {
            $err_report['ENGINE=InnoDB'] = array("Engine 'InnoDB' is not active", "inactive");
        }

        //Check innodb_strict_mode
        $res = $conn->query("SELECT @@GLOBAL.innodb_strict_mode");
        $innodb_strict_mode = $res->fields[0];
        if ($innodb_strict_mode == 0) {
            $errInnodbMode = true;
        } else {
            $errInnodbMode = false;
            $err_report['innodb_strict_mode'] = array("innodb_strict_mode is activ and should be disabled", "activ");
        }

        //Check character_set_database
        $res = $conn->query("SELECT @@character_set_database");
        $characterSet = $res->fields[0];
        if ($characterSet === "utf8" || $characterSet === "utf8mb3" || $characterSet === "utf8mb4") {
            $errCharacterSet = true;
            if($characterSet !== "utf8mb4") {
                $errCharacterSet = false;
                $err_report['character_set_database'] = array("Should be utf8mb4 (utf8mb3 or utf8 might work as well)", $characterSet);
            }
        } else {
            $errCharacterSet = false;
            $err_report['character_set_database'] = array("The character set is incorrect and should be set to UTF-8", $characterSet);
        }

        //Check collation_database
        $res = $conn->query("SELECT @@collation_database");
        $collation = $res->fields[0];
        if ($collation === 'utf8_unicode_ci') {
            $errCollationDatabase = true;
        } else {
            $errCollationDatabase = false;
            $err_report['collation_database'] = array("collation is not correct and should be set to utf8_unicode_ci", $collation);
        }

        if($errSqlMode && $errInnodbActive && $errInnodbMode && $errCharacterSet && $errCollationDatabase) {
            return true;
        }
        else{

            return $err_report;
        }
    }
    return false;
}

/**
 * Retrieves the version of the connected database.
 *
 * @param string $db_type   The type of the database (e.g., 'mysqli', 'pdo_mysql').
 * @param string $db_host   The hostname of the database server (e.g., 'localhost').
 * @param string $db_user   The username for the database connection.
 * @param string $db_password The password for the database connection.
 * @return mixed Returns the MySQL version string if connected successfully; otherwise, returns false.
 */
function dbVersion($db_type, $db_host, $db_user, $db_password) {
    require('libraries/adodb/adodb.inc.php');
    $conn = NewADOConnection($db_type);
    if(@$conn->Connect($db_host, $db_user, $db_password)) {
        $serverInfo = $conn->ServerInfo();
        if(isMySQL($db_type)) {
            $mysql_server_version = getMySQLVersion($serverInfo);
            return $mysql_server_version;
        }
    }
    return false;
}


// ****** Required File System Privileges **********************************************************************************

/**
 * Checks the filesystem privileges for specified paths.
 *
 * This function verifies whether certain files and directories exist, 
 * and whether they are readable and writable. It records the results in 
 * an associative array and also logs the details to a text file for 
 * review.
 *
 * @return array An associative array with paths as keys and an array of 
 *               booleans indicating existence and write access as values.
 */
function fileSystemPrivileges() {
    $pathRequiredPrivileges = array(
        'tabdata.php',
        'parent_tabdata.php', 
        'cache',
        'storage/',
        'user_privileges/',
        'modules/',
        'cron/',
        'backup/',
        'test/',
        'logs/')
        ;

    $pathPrivileges = array();
    foreach ($pathRequiredPrivileges as $path) {
        if(file_exists($path)) {
            $readable = is_readable($path);
            $writable = is_writable($path);
            if($readable && $writable) {
                $pathPrivileges[$path] = array(true, true);
            }
            else{
                $pathPrivileges[$path] = array(true, false);
            }
        }
        else {
            $pathPrivileges[$path] = array(false, false);
        }
    }
    return $pathPrivileges;
}

// ****** Display Output ***************************************************************************************************

function showDataOnDisplay($systemRequirementData, $dbConnectionStatus = '', $pathPrivileges, $dbSettingsStatus = true, $dbVersion = NULL) {
    $displayHTML = '
    <!doctype html>
        <html lang="en">
        <head>
            <meta charset="UTF-8" />
            <title>System Requirements Check</title>
        </head>
        <body>
            <div class="container" style="max-width: 1200px; margin: 0 auto; padding: 20px;">
                <div class="main-container">
                    <h2 style="text-align: center; margin-bottom: 20px;">Installation Requirements</h2>
                    <div class="row" style="display: flex; gap: 20px; margin-bottom: 20px;">

                        <!-- PHP Configuration -->
                        <div class="box" style="flex: 1; border: 1px solid #ccc; padding: 20px; border-radius: 5px;">
                            <h3 style="text-align: center;">PHP Configuration</h3>
                            <table class="config-table" style="width: 100%; border-collapse: collapse;">
                                <tr style="background-color: #f2f2f2;">
                                    <th style="border: 1px solid #ddd; padding: 8px;">Configuration</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Required Value</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Current Value</th>
                                </tr>';

            foreach ($systemRequirementData['preInstallConfig'] as $configName => $info) {
                $requiredValue = $info[1] == 1 ? 'Yes' : $info[1];
                $presentValue = '';
                $style = '';

                if ($configName === 'PHP Version' || $configName === 'Apache-Version' || $configName === 'Nginx-Version') {
                    $presentValue = $info[0];
                    $style = (version_compare($presentValue, $requiredValue, '<')) ? ' color: red' : '';
                } elseif ($configName === 'OS') {
                    $presentValue = is_string($info[2]) ? $info[2] : "No";
                    $requiredValue = is_array($info[1]) ? implode("<br>", $info[1]) : $info[1];
                    $style = (is_array($info[1]) && !in_array($presentValue, $info[1])) ? ' color: red' : '';
                } elseif ($configName === 'SSL') {
                    if($info[2] == 1) {
                        $presentValue = "On";
                    } else {
                        $presentValue = "Off";  
                        if(!empty($info[3])) {
                            $presentValue .= "<br><br>".$info[3];
                        }
                    }
                    $style = ($requiredValue !== $presentValue) ? ' color: red;' : '';
                } else {
                    $presentValue = $info[2] == 1 ? 'Yes' : 'No';
                    $style = ($requiredValue !== $presentValue) ? ' color: red;' : '';
                }

                $displayHTML .= "<tr>
                                    <td style='border: 1px solid #ddd; padding: 8px;'>$configName</td>
                                    <td style='border: 1px solid #ddd; padding: 8px;'>$requiredValue</td>
                                    <td style='border: 1px solid #ddd; padding: 8px;$style'>$presentValue</td>
                                </tr>";
            }

            $displayHTML .= '
                            </table>
                        </div>

                        <!-- PHP Settings -->
                        <div class="box" style="flex: 1; border: 1px solid #ccc; padding: 20px; border-radius: 5px;">
                            <h3 style="text-align: center;">PHP Settings</h3>
                            <table class="config-table" style="width: 100%; border-collapse: collapse;">
                                <tr style="background-color: #f2f2f2;">
                                    <th style="border: 1px solid #ddd; padding: 8px;">Directive</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Recommended Value</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Current Value</th>
                                </tr>';

            foreach ($systemRequirementData['directiveValues'] as $directive => $currentValue) {
                $recommendedValue = isset($systemRequirementData['recommendedDirectives'][$directive]) ? $systemRequirementData['recommendedDirectives'][$directive] : 'N/A';
                $style = (strtolower($currentValue) !== strtolower($recommendedValue) && $currentValue <= $recommendedValue) ? 'color: red;' : '';
                $displayHTML .= "<tr>
                                    <td style='border: 1px solid #ddd; padding: 8px;'>" . htmlspecialchars($directive) . "</td>
                                    <td style='border: 1px solid #ddd; padding: 8px;'>" . htmlspecialchars($recommendedValue) . "</td>
                                    <td style='border: 1px solid #ddd; padding: 8px;$style'>" . htmlspecialchars($currentValue) . "</td>
                                </tr>";
            }

            $displayHTML .= '
                            </table>
                        </div>

                        <!-- Filesystem Permissions -->
                        <div class="box" style="flex: 1; border: 1px solid #ccc; padding: 20px; border-radius: 5px;">
                            <h3 style="text-align: center;">Filesystem Permissions</h3>
                            <table class="config-table" style="width: 100%; border-collapse: collapse;">
                                <tr style="background-color: #f2f2f2;">
                                    <th style="border: 1px solid #ddd; padding: 8px;">Path</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Status</th>
                                </tr>';

            foreach ($pathPrivileges as $path => $status) {
                $accessStatus = !$status[0] ? 'Does not exist' : ($status[1] ? 'Readable & Writable' : 'No access');
                $style = (!$status[0] || !$status[1]) ? ' color: red' : '';
                
                $displayHTML .= "
                                    <tr>
                                        <td style='border: 1px solid #ddd; padding: 8px;'>" . htmlspecialchars($path) . "</td>
                                        <td style='border: 1px solid #ddd; padding: 8px;$style'>" . htmlspecialchars($accessStatus) . "</td>
                                    </tr>";
            }

            $displayHTML .= '
                            </table>
                        </div>
                    </div>

                    <!-- Database Connection Status -->
                    <div class="row" style="margin-top: 20px;">
                        <div class="box" style="border: 1px solid #ccc; padding: 20px; border-radius: 5px;">
                            <h3 style="text-align: center;">Database Connection Status</h3>
                            <table class="config-table" style="width: 100%; border-collapse: collapse;">
                                <tr style="background-color: #f2f2f2;">
                                    <th style="border: 1px solid #ddd; padding: 8px;">Status</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Version</th>
                                    <th style="border: 1px solid #ddd; padding: 8px;">Additional Messages</th>
                                </tr>
                                <tr>
                                    <td style="border: 1px solid #ddd; padding: 8px; ' . ($dbConnectionStatus['flag'] ? 'color: green;' : 'color: red;') . '">' .
                                        ($dbConnectionStatus['flag'] ? 'Database connection successful!' : 'Connection failed') . '</td>
                                    <td style="border: 1px solid #ddd; padding: 8px; color: blue;">' .
                                        ($dbVersion === null ? 'DB is not connected' : ($dbVersion === false ? 'Unknown' : htmlspecialchars($dbVersion))) . '</td>
                                    <td style="border: 1px solid #ddd; padding: 8px;">';

            if ($dbConnectionStatus['flag']) {
                if ($dbSettingsStatus === true) {
                    $displayHTML .= '<p style="color: green;">Database settings are correct.</p>';
                } elseif (is_array($dbSettingsStatus) && !empty($dbSettingsStatus)) {
                    $displayHTML .= '<ul>';
                    foreach ($dbSettingsStatus as $setting => $info) {
                        $error_message = htmlspecialchars($info[0]);
                        $current_value = isset($info[1]) ? ($info[1] !== false ? htmlspecialchars($info[1]) : 'N/A') : '';
                        if($current_value !== '') {
                            $displayHTML .= "<li style='color: red;'><strong>" . htmlspecialchars($setting) . ":</strong> $error_message (Current: <em>$current_value</em>)</li>";
                        }
                        else {
                            $displayHTML .= "<li style='color: red;'><strong>" . htmlspecialchars($setting) . ":</strong> $error_message </li>";
                        }
                    }
                    $displayHTML .= '</ul>';
                } else {
                    $displayHTML .= "<p>No specific errors found.</p>";
                }
            } else {
                $displayHTML .= '<p style="color: red;">'. $dbConnectionStatus['error_msg'].'</p>';
                if (!empty($dbConnectionStatus['error_msg_info'])) {
                    $displayHTML .= '<p style="color: red;">' . $dbConnectionStatus['error_msg_info'] . '</p>';
                }
            }

            $displayHTML .= '
                                    </td>
                                </tr>
                            </table>
                        </div>
                    </div>
                </div>
            </div>
        </body>';

    echo $displayHTML;
}