<?php
defined($security_key) or exit;

//------------------------------------------
// Secure Software Download API
// Validates time-based URL token and streams firmware files
//------------------------------------------

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

// STEP 1: Validate token parameter exists
if (!isset($_GET['token']) || $_GET['token'] == '') {
    http_response_code(400);
    echo json_encode(["error" => "MISSING_TOKEN", "message" => "Download token required"]);
    exit;
}

$download_start = microtime(true);

// URL decode the token in case it was encoded during transmission
$url_token = urldecode($_GET['token']);

// STEP 2: Validate and decode URL token using standalone secure function
$token_data = validate_secure_download_token($url_token);

if (isset($token_data['error'])) {
    http_response_code(403);
    echo json_encode([
        "error" => $token_data['error'],
        "message" => $token_data['message']
    ]);
    exit;
}

$serial_number = $token_data['sn'];
$version_id = $token_data['version_id'];

// STEP 3: Get equipment data (reuse software_update.php logic)
$sql = 'SELECT
            e.rowID as equipment_rowid,
            e.productrowid,
            e.sw_version as current_sw_version,
            e.hw_version,
            e.sw_version_license,
            e.accounthierarchy,
            p.productcode
        FROM equipment e
        JOIN products p ON e.productrowid = p.rowID
        WHERE e.serialnumber = ?';

$stmt = $pdo->prepare($sql);
$stmt->execute([$serial_number]);
$equipment = $stmt->fetch(PDO::FETCH_ASSOC);

if (!$equipment) {
    http_response_code(404);
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'status' => 'failed',
        'error_message' => 'Equipment not found',
        'createdby' => $username
    ]);
    echo json_encode(["error" => "EQUIPMENT_NOT_FOUND", "message" => "Equipment not found"]);
    exit;
}

// STEP 4: Get version data
$sql = 'SELECT
            psv.rowID,
            psv.version,
            psv.name,
            psv.file_path,
            psv.hw_version,
            psv.status
        FROM products_software_versions psv
        WHERE psv.rowID = ?';

$stmt = $pdo->prepare($sql);
$stmt->execute([$version_id]);
$version = $stmt->fetch(PDO::FETCH_ASSOC);

if (!$version) {
    http_response_code(404);
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'status' => 'failed',
        'error_message' => 'Version not found',
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);
    echo json_encode(["error" => "VERSION_NOT_FOUND", "message" => "Version not found"]);
    exit;
}

if ($version['status'] != 1) {
    http_response_code(403);
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'status' => 'failed',
        'error_message' => 'Version inactive',
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);
    echo json_encode(["error" => "VERSION_INACTIVE", "message" => "Version is not active"]);
    exit;
}

// STEP 5: Check version is assigned to product
$sql = 'SELECT COUNT(*) as assigned
        FROM products_software_assignment
        WHERE product_id = ? AND software_version_id = ? AND status = 1';

$stmt = $pdo->prepare($sql);
$stmt->execute([$equipment['productrowid'], $version_id]);
$assignment = $stmt->fetch(PDO::FETCH_ASSOC);

if ($assignment['assigned'] == 0) {
    http_response_code(403);
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'status' => 'failed',
        'error_message' => 'Version not assigned to product',
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);
    echo json_encode(["error" => "VERSION_NOT_ASSIGNED", "message" => "Version not assigned to product"]);
    exit;
}

// STEP 6: Hardware version compatibility
// Only check if version has hw_version requirement (not NULL or empty)
// Match logic from software_update.php line 103
if ($version['hw_version'] && $version['hw_version'] != '') {
    if ($equipment['hw_version'] && $version['hw_version'] != $equipment['hw_version']) {
        http_response_code(403);
        log_download([
            'user_id' => $user_data['id'],
            'version_id' => $version_id,
            'status' => 'failed',
            'error_message' => 'Hardware version mismatch',
            'accounthierarchy' => $equipment['accounthierarchy'],
            'createdby' => $username
        ]);
        echo json_encode(["error" => "HW_VERSION_MISMATCH", "message" => "Hardware version incompatible"]);
        exit;
    }
}

// STEP 7: License validation (reuse software_update.php logic)
$current_sw_version = $equipment['current_sw_version'];

// Get upgrade pricing
$sql = 'SELECT price, 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 from_ver.version = ? AND pup.is_active = 1';

$stmt = $pdo->prepare($sql);
$stmt->execute([$version_id, $current_sw_version]);
$upgrade_pricing = $stmt->fetch(PDO::FETCH_ASSOC);

$final_price = $upgrade_pricing['price'] ?? '0.00';

if ($final_price > 0) {
    // Paid upgrade - check license
    $sw_version_license = $equipment['sw_version_license'];

    if (!$sw_version_license) {
        http_response_code(402);
        log_download([
            'user_id' => $user_data['id'],
            'version_id' => $version_id,
            'status' => 'failed',
            'error_message' => 'License required',
            'accounthierarchy' => $equipment['accounthierarchy'],
            'createdby' => $username
        ]);
        echo json_encode([
            "error" => "LICENSE_REQUIRED",
            "message" => "Valid license required",
            "price" => $final_price,
            "currency" => $upgrade_pricing['currency']
        ]);
        exit;
    }

    // Validate license
    $sql = 'SELECT status, starts_at, expires_at
            FROM products_software_licenses
            WHERE license_key = ? AND equipment_id = ?';

    $stmt = $pdo->prepare($sql);
    $stmt->execute([$sw_version_license, $equipment['equipment_rowid']]);
    $license = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$license || $license['status'] != 1) {
        http_response_code(402);
        log_download([
            'user_id' => $user_data['id'],
            'version_id' => $version_id,
            'status' => 'failed',
            'error_message' => 'Invalid license',
            'accounthierarchy' => $equipment['accounthierarchy'],
            'createdby' => $username
        ]);
        echo json_encode(["error" => "INVALID_LICENSE", "message" => "License is invalid"]);
        exit;
    }

    // Check license date validity
    $now = date('Y-m-d H:i:s');
    if (($license['starts_at'] && $license['starts_at'] > $now) ||
        ($license['expires_at'] && $license['expires_at'] < $now)) {
        http_response_code(402);
        log_download([
            'user_id' => $user_data['id'],
            'version_id' => $version_id,
            'status' => 'failed',
            'error_message' => 'License expired',
            'accounthierarchy' => $equipment['accounthierarchy'],
            'createdby' => $username
        ]);
        echo json_encode(["error" => "LICENSE_EXPIRED", "message" => "License is expired"]);
        exit;
    }
}

// STEP 8: Build file path and verify exists
$firmware_path = dirname(__FILE__, 4) . '/firmware/' . $version['file_path'];

if (!file_exists($firmware_path)) {
    http_response_code(404);
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'status' => 'failed',
        'error_message' => 'File not found on server',
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);
    echo json_encode(["error" => "FILE_NOT_FOUND", "message" => "Firmware file not available"]);
    exit;
}

// STEP 9: Stream file and log
$file_size = filesize($firmware_path);

try {
    // Log successful download before streaming
    $download_time = round(microtime(true) - $download_start);

    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'file_size' => $file_size,
        'download_time_seconds' => $download_time,
        'status' => 'success',
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);

    // Stream file (function handles path traversal check and exits after streaming)
    stream_file_download($firmware_path, $version['file_path']);

} catch (Exception $e) {
    log_download([
        'user_id' => $user_data['id'],
        'version_id' => $version_id,
        'file_size' => $file_size,
        'status' => 'failed',
        'error_message' => $e->getMessage(),
        'accounthierarchy' => $equipment['accounthierarchy'],
        'createdby' => $username
    ]);

    http_response_code(500);
    echo json_encode(["error" => "DOWNLOAD_FAILED", "message" => "Download failed"]);
}
?>