<?php
defined($security_key) or exit;
ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
error_reporting(E_ALL);
//------------------------------------------
// Software Available Check API
// Returns boolean indicating if software updates are available
//------------------------------------------

//Connect to DB
$pdo = dbConnect($dbname);

//NEW ARRAY
$criterias = [];
$clause = '';
$debug = [];

//Check for $_GET variables and build up clause
if(isset($get_content) && $get_content!=''){
    //GET VARIABLES FROM URL
    $requests = explode("&", $get_content);
    //Check for keys and values
    foreach ($requests as $y){
        $v = explode("=", $y);
        //INCLUDE VARIABLES IN ARRAY
        $criterias[$v[0]] = $v[1];
    }
}

if (debug) {
    $debug['request_parameters'] = $criterias;
    $debug['timestamp'] = date('Y-m-d H:i:s');
}

// IF SN IS PROVIDED, CHECK FOR AVAILABLE UPGRADES
if (isset($criterias['sn']) && $criterias['sn'] != ''){

    //default response
    $software_available = "no";

    //check if current version is send and update the equipment record
    if(isset($criterias['version']) && $criterias['version'] !=''){
        $sql = 'UPDATE equipment SET sw_version = ?, updatedby = ? WHERE serialnumber = ? ';
        $stmt = $pdo->prepare($sql);
        $stmt->execute([$criterias['version'],$username,$criterias['sn']]);
    }

    //check if current hw_version is send and update the equipment record
    if(isset($criterias['hw_version']) && $criterias['hw_version'] !=''){
        // Translate hardware version to standardized format
        $translated_hw_version = translateDeviceHardwareVersion($criterias['hw_version']);
        $sql = 'UPDATE equipment SET hw_version = ?, updatedby = ? WHERE serialnumber = ? ';
        $stmt = $pdo->prepare($sql);
        $stmt->execute([$translated_hw_version,$username,$criterias['sn']]);
    }

    //GET EQUIPMENT AND PRODUCT DATA BASED ON SERIAL NUMBER
    $sql = 'SELECT
                p.rowID as product_rowid,
                p.productcode,
                e.sw_version as current_sw_version,
                e.hw_version,
                e.sw_version_license,
                e.sw_version_upgrade,
                e.rowID as equipment_rowid
            FROM equipment e
            JOIN products p ON e.productrowid = p.rowID
            WHERE e.serialnumber = ?';
    $stmt = $pdo->prepare($sql);
    $stmt->execute([$criterias['sn']]);
    $equipment_data = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$equipment_data) {
        $messages = ["error" => "No equipment found for serialnumber"];
    } else {
        $product_rowid = $equipment_data['product_rowid'];
        $productcode = $equipment_data['productcode'];
        $current_sw_version = $equipment_data['current_sw_version'];
        $hw_version = $equipment_data['hw_version'];
        $sw_version_license = $equipment_data['sw_version_license'];
        $sw_version_upgrade = $equipment_data['sw_version_upgrade'];
        $equipment_rowid = $equipment_data['equipment_rowid'];

        if (debug) {
            $debug['equipment_data'] = [
                'product_rowid' => $product_rowid,
                'productcode' => $productcode,
                'current_sw_version_raw' => $current_sw_version,
                'hw_version' => $hw_version,
                'sw_version_upgrade' => $sw_version_upgrade
            ];
        }

        // Normalize software version for comparison (lowercase, trim leading zeros)
        $current_sw_version = strtolower(ltrim($current_sw_version, '0'));

        // Translate incoming hw_version parameter for comparison if provided
        $comparison_hw_version = $hw_version;
        $hw_version_from_request = null;
        if(isset($criterias['hw_version']) && $criterias['hw_version'] !=''){
            $hw_version_from_request = $criterias['hw_version'];
            $comparison_hw_version = translateDeviceHardwareVersion($criterias['hw_version']);
        }

        if (debug) {
            $debug['normalized_data'] = [
                'current_sw_version' => $current_sw_version,
                'hw_version_from_request' => $hw_version_from_request,
                'comparison_hw_version' => $comparison_hw_version,
                'hw_version_valid' => ($comparison_hw_version !== '')
            ];
        }

        // Check if hardware version is invalid (all zeros)
        if ($hw_version_from_request && $comparison_hw_version === '') {
            $messages = ["software_available" => "error", "error" => "Invalid hardware version (000000) - device may not be properly initialized"];
            if (debug) {
                $messages['debug'] = $debug;
            }
            echo json_encode($messages, JSON_UNESCAPED_UNICODE);
            exit;
        }

        // Check if sw_version_upgrade is set - this overrides normal availability check
        if (!empty($sw_version_upgrade)) {
            if (debug) {
                $debug['sw_version_upgrade_check'] = [
                    'sw_version_upgrade_id' => $sw_version_upgrade,
                    'checking_override' => true
                ];
            }

            // Check if this version exists and is active
            $sql = 'SELECT
                        psv.rowID as version_id,
                        psv.version,
                        psv.name,
                        psv.description,
                        psv.mandatory,
                        psv.latest,
                        psv.hw_version,
                        psv.file_path,
                        psv.status
                    FROM products_software_versions psv
                    WHERE psv.rowID = ?';
            $stmt = $pdo->prepare($sql);
            $stmt->execute([$sw_version_upgrade]);
            $upgrade_version = $stmt->fetch(PDO::FETCH_ASSOC);

            if ($upgrade_version && $upgrade_version['status'] == 1) {
                // Valid override found - check if different from current version
                $normalized_upgrade_version = strtolower(ltrim($upgrade_version['version'], '0'));
                
                if (debug) {
                    $debug['sw_version_upgrade_check']['found_version'] = [
                        'version' => $upgrade_version['version'],
                        'name' => $upgrade_version['name'],
                        'normalized' => $normalized_upgrade_version,
                        'status' => $upgrade_version['status'],
                        'is_different_from_current' => ($current_sw_version != $normalized_upgrade_version)
                    ];
                }

                if ($current_sw_version && $normalized_upgrade_version == $current_sw_version) {
                    // Override version is same as current - no upgrade available
                    $software_available = "no";
                    if (debug) {
                        $debug['sw_version_upgrade_check']['decision'] = 'Override version is same as current version';
                    }
                } else {
                    // Override version is different - upgrade is available
                    $software_available = "yes";
                    if (debug) {
                        $debug['sw_version_upgrade_check']['decision'] = 'Override version is available';
                    }
                }

                $messages = ["software_available" => $software_available];
                
                if (debug) {
                    debuglog(json_encode($debug));
                }
                
                echo json_encode($messages, JSON_UNESCAPED_UNICODE);
                exit;
            } else {
                // Override version not found or inactive - fall back to standard check
                if (debug) {
                    $debug['sw_version_upgrade_check']['found_version'] = $upgrade_version ? 'found but inactive' : 'not found';
                    $debug['sw_version_upgrade_check']['decision'] = 'Falling back to standard check';
                }
            }
        }

        //GET ALL ACTIVE SOFTWARE ASSIGNMENTS for this product with matching HW version
        $sql = 'SELECT
                    psv.rowID as version_id,
                    psv.version,
                    psv.name,
                    psv.description,
                    psv.mandatory,
                    psv.latest,
                    psv.hw_version,
                    psv.file_path
                FROM products_software_assignment psa
                JOIN products_software_versions psv ON psa.software_version_id = psv.rowID
                WHERE psa.product_id = ?
                    AND psa.status = 1
                    AND (psv.hw_version = ? OR psv.hw_version IS NULL OR psv.hw_version = "")';

        $stmt = $pdo->prepare($sql);
        $stmt->execute([$product_rowid, $comparison_hw_version]);
        $versions = $stmt->fetchAll(PDO::FETCH_ASSOC);

        if (debug) {
            $debug['active_assignments'] = [
                'count' => count($versions),
                'versions' => array_map(function($v) {
                    return [
                        'version_id' => $v['version_id'],
                        'version' => $v['version'],
                        'name' => $v['name'],
                        'hw_version' => $v['hw_version'],
                        'latest' => $v['latest']
                    ];
                }, $versions)
            ];
        }

        if (empty($versions)) {
            // No versions available
            $software_available = "no";
            if (debug) {
                $debug['decision'] = 'No active software assignments found';
            }
        } else {
            $available_upgrades = 0;
            $has_priced_options = false;
            $has_latest_version_different = false;
            $version_details = []; // Track version details for downgrade prevention

            if (debug) {
                $debug['version_checks'] = [];
            }

            foreach ($versions as $version) {
                //Normalize version for comparison (lowercase, trim leading zeros)
                $normalized_version = strtolower(ltrim($version['version'], '0'));

                //Skip if this is the current version
                if ($current_sw_version && $normalized_version == $current_sw_version) {
                    continue;
                }

                //Check if this version should be shown (same logic as software_update)
                $show_version = false;
                $final_price = '0.00';
                $decision_reason = '';

                if (debug) {
                    $version_check = [
                        'version' => $version['version'],
                        'name' => $version['name'],
                        'normalized' => $normalized_version,
                        'is_current' => ($current_sw_version && $normalized_version == $current_sw_version)
                    ];
                }

                if (!$current_sw_version || $current_sw_version == '') {
                    //No current version - show all
                    $show_version = true;
                    $decision_reason = 'No current version - showing all';
                } else {
                    //Check if this version is part of ANY upgrade path system (either FROM or TO)
                    $sql = 'SELECT COUNT(*) as path_count
                            FROM products_software_upgrade_paths
                            WHERE (to_version_id = ? OR from_version_id = ?) AND is_active = 1';
                    $stmt = $pdo->prepare($sql);
                    $stmt->execute([$version['version_id'], $version['version_id']]);
                    $path_check = $stmt->fetch(PDO::FETCH_ASSOC);

                    if (debug) {
                        $version_check['path_count'] = $path_check['path_count'];
                    }

                    if ($path_check['path_count'] == 0) {
                        //Not part of any upgrade path system - show as free upgrade
                        $show_version = true;
                        $decision_reason = 'No upgrade paths defined - showing as free';
                    } else {
                        //Part of an upgrade path system
                        //Only show if there's an explicit path FROM current version TO this version
                        $sql = 'SELECT pup.price, pup.currency
                                FROM products_software_upgrade_paths pup
                                JOIN products_software_versions from_ver ON pup.from_version_id = from_ver.rowID
                                WHERE pup.to_version_id = ?
                                  AND (LOWER(TRIM(LEADING "0" FROM from_ver.version)) = ?
                                       OR pup.from_version_id = 9999999)
                                  AND pup.is_active = 1';
                        $stmt = $pdo->prepare($sql);
                        $stmt->execute([$version['version_id'], $current_sw_version]);
                        $upgrade_path = $stmt->fetch(PDO::FETCH_ASSOC);

                        if ($upgrade_path) {
                            //Valid upgrade path found FROM current version
                            $show_version = true;
                            $final_price = $upgrade_path['price'] ?? '0.00';
                            $decision_reason = 'Found upgrade path from current with price: ' . $final_price;
                        } else {
                            $decision_reason = 'Has upgrade paths but none from current version';
                        }
                    }
                }

                if (debug) {
                    $version_check['show_version'] = $show_version;
                    $version_check['reason'] = $decision_reason;
                }

                if ($show_version) {
                    $available_upgrades++;

                    //Check if there's a valid license for this upgrade
                    if ($final_price > 0 && $sw_version_license) {
                        //Check if the license is valid
                        $sql = 'SELECT status, starts_at, expires_at
                                FROM products_software_licenses
                                WHERE license_key = ?';
                        $stmt = $pdo->prepare($sql);
                        $stmt->execute([$sw_version_license]);
                        $license = $stmt->fetch(PDO::FETCH_ASSOC);

                        if ($license && $license['status'] == 1) {
                            $now = date('Y-m-d H:i:s');
                            $start_at = $license['starts_at'];
                            $expires_at = $license['expires_at'];

                            //Check if license is within valid date range
                            if ((!$start_at || $start_at <= $now) && (!$expires_at || $expires_at >= $now)) {
                                $final_price = '0.00';
                            }
                        }
                    }

                    // Store version details for downgrade prevention check (after license application)
                    $version_details[] = [
                        'show_version' => true,
                        'final_price' => $final_price
                    ];

                    // Check for priced options
                    if ($final_price > 0) {
                        $has_priced_options = true;
                    }

                    // Check if there's a "latest" flagged version that's different from current
                    if ($version['latest'] == 1 && $normalized_version != $current_sw_version) {
                        $has_latest_version_different = true;
                    }

                    if (debug) {
                        $version_check['final_price'] = $final_price;
                        $version_check['has_priced_option'] = ($final_price > 0);
                        $version_check['is_latest_different'] = ($version['latest'] == 1 && $normalized_version != $current_sw_version);
                    }
                }

                if (debug) {
                    $debug['version_checks'][] = $version_check;
                }
            }

            //PREVENT DOWNGRADE FROM PAID VERSION TO FREE VERSION (if config enabled)
            if (defined('PREVENT_PAID_VERSION_DOWNGRADE') && PREVENT_PAID_VERSION_DOWNGRADE && $current_sw_version) {
                // Check if user is currently on a paid version (check if there was a paid upgrade path TO current version)
                $sql = 'SELECT COUNT(*) as paid_to_current
                        FROM products_software_upgrade_paths pup
                        JOIN products_software_versions to_ver ON pup.to_version_id = to_ver.rowID
                        WHERE LOWER(TRIM(LEADING "0" FROM to_ver.version)) = ?
                            AND pup.price > 0
                            AND pup.is_active = 1';
                $stmt = $pdo->prepare($sql);
                $stmt->execute([$current_sw_version]);
                $paid_check = $stmt->fetch(PDO::FETCH_ASSOC);
                $is_current_paid_version = ($paid_check['paid_to_current'] > 0);

                if (debug) {
                    $debug['downgrade_prevention'] = [
                        'enabled' => true,
                        'current_version' => $current_sw_version,
                        'is_current_paid_version' => $is_current_paid_version
                    ];
                }

                // If current version is paid, recalculate available_upgrades excluding free versions
                if ($is_current_paid_version) {
                    $available_upgrades_before = $available_upgrades;
                    $available_upgrades = 0;

                    // Recount only paid upgrades (exclude free versions)
                    foreach ($version_details as $detail) {
                        if ($detail['show_version'] && floatval($detail['final_price']) > 0) {
                            $available_upgrades++;
                        }
                    }

                    if (debug) {
                        $debug['downgrade_prevention']['available_upgrades_before'] = $available_upgrades_before;
                        $debug['downgrade_prevention']['available_upgrades_after'] = $available_upgrades;
                        $debug['downgrade_prevention']['message'] = 'Excluded free versions to prevent downgrade from paid version';
                    }
                }
            }

            // Simple logic: if any upgrades are available to show, return "yes"
            if ($available_upgrades > 0) {
                $software_available = "yes";
                $availability_reason = "Software upgrades available";
            } else {
                $software_available = "no";
                $availability_reason = "No upgrades available";
            }

            if (debug) {
                $debug['final_decision'] = [
                    'available_upgrades' => $available_upgrades,
                    'has_priced_options' => $has_priced_options,
                    'has_latest_version_different' => $has_latest_version_different,
                    'software_available' => $software_available,
                    'reason' => $availability_reason
                ];
            }
        }

        $messages = ["software_available" => $software_available];

        if (debug) {
            debuglog(json_encode($debug));
        }
    }
} else {
    $messages = ["error" => "No serialnumber found"];
}

//Encrypt results
$messages = json_encode($messages, JSON_UNESCAPED_UNICODE);

//Send results
echo $messages;

?>