if not TowBarMod then TowBarMod = {} end
if not TowBarMod.Hook then TowBarMod.Hook = {} end

require("TowBar/VehicleCompatibility")

local DefaultTowBarTowMass = 200
local FreeRollTickInterval = 15
local freeRollTickCounter = 0

local function tryVehicleCall(vehicle, methodName, arg)
    if not vehicle or not methodName then return false, nil end
    local method = vehicle[methodName]
    if method == nil then return false, nil end

    return pcall(function()
        if arg ~= nil then
            return method(vehicle, arg)
        end
        return method(vehicle)
    end)
end

local function storeOriginalVehicleCall(vehicle, modData, key, getterName)
    if not vehicle or not modData or modData[key] ~= nil then return end

    local ok, value = tryVehicleCall(vehicle, getterName)
    if ok and value ~= nil then
        modData[key] = value
    end
end

local function applyFreeRollingTowState(vehicle)
    if not vehicle then return end

    local modData = vehicle:getModData()
    if not modData then return end

    if modData.towBarOriginalMass == nil then
        modData.towBarOriginalMass = vehicle:getMass()
    end
    if modData.towBarOriginalBrakingForce == nil then
        modData.towBarOriginalBrakingForce = vehicle:getBrakingForce()
    end
    storeOriginalVehicleCall(vehicle, modData, "towBarOriginalParkingBrakeOn", "isParkingBrakeOn")
    storeOriginalVehicleCall(vehicle, modData, "towBarOriginalParkingBrake", "getParkingBrake")
    storeOriginalVehicleCall(vehicle, modData, "towBarOriginalHandbrake", "isHandbrake")

    local configuredTowMass = TowBarMod.Config and tonumber(TowBarMod.Config.towedVehicleRollingMass)
    vehicle:setMass(configuredTowMass or DefaultTowBarTowMass)
    vehicle:setBrakingForce(0)

    if modData.towBarOriginalParkingBrakeOn ~= nil then
        tryVehicleCall(vehicle, "setParkingBrakeOn", false)
    end
    if modData.towBarOriginalParkingBrake ~= nil then
        tryVehicleCall(vehicle, "setParkingBrake", false)
    end
    if modData.towBarOriginalHandbrake ~= nil then
        tryVehicleCall(vehicle, "setHandbrake", false)
    end

    -- Match the working wrecker path. Recalculating total mass here would
    -- immediately replace the temporary towing mass in multiplayer; creating
    -- the rigid constraint below notifies Bullet of the changed vehicle state.
end

TowBarMod.Hook.applyFreeRollingTowState = applyFreeRollingTowState

local function restoreFreeRollingTowState(vehicle, modData)
    if not vehicle or not modData then return end

    if modData.towBarOriginalMass ~= nil then
        vehicle:setMass(modData.towBarOriginalMass)
    end
    if modData.towBarOriginalBrakingForce ~= nil then
        vehicle:setBrakingForce(modData.towBarOriginalBrakingForce)
    end
    if modData.towBarOriginalParkingBrakeOn ~= nil then
        tryVehicleCall(vehicle, "setParkingBrakeOn", modData.towBarOriginalParkingBrakeOn)
    end
    if modData.towBarOriginalParkingBrake ~= nil then
        tryVehicleCall(vehicle, "setParkingBrake", modData.towBarOriginalParkingBrake)
    end
    if modData.towBarOriginalHandbrake ~= nil then
        tryVehicleCall(vehicle, "setHandbrake", modData.towBarOriginalHandbrake)
    end

    vehicle:constraintChanged()
    vehicle:updateTotalMass()
end

local function getTowBarItem(playerObj)
    if not playerObj then return nil end
    local inventory = playerObj:getInventory()
    if not inventory then return nil end
    return inventory:getItemFromTypeRecurse("TowBar.TowBar")
end

local function sendTowAttachCommand(playerObj, args)
    if not playerObj or not args then return end
    -- SP and MP now share the same authoritative attach lifecycle.
    sendClientCommand(playerObj, "towbar", "attachTowBar", args)
end

local TowbarVariantSize = 24
local TowbarMaxIndex = TowbarVariantSize - 1
local TowbarFirstZ = 1.0
local TowbarSlotStep = 0.1
-- Measured from Towbar.fbx at its original 0.01 script scale. The visual is
-- enlarged uniformly, so its center must move outward by the scaled half-length
-- to keep the inner end on the same vehicle-hitbox contact point.
local TowbarVisualScale = 2.5
local TowbarModelLength = 0.9714089036
local TowbarScaledModelLength = TowbarModelLength * TowbarVisualScale
local TowbarModelHalfLength = TowbarScaledModelLength / 2
local VanillaScaleMin = 1.5
local VanillaScaleMax = 2.0

local function getTowbarFrontEdgeZ(script)
    if not script then return nil end

    local ok, shape = pcall(function()
        return script:getPhysicsChassisShape()
    end)
    if not ok or not shape then return nil end

    local shapeOk, shapeZ = pcall(function()
        return shape:z()
    end)
    if not shapeOk or type(shapeZ) ~= "number" or shapeZ <= 0 then
        return nil
    end

    local centerOk, center = pcall(function()
        return script:getCenterOfMassOffset()
    end)
    if not centerOk or not center then return nil end

    local zOk, centerZ = pcall(function()
        return center:z()
    end)
    if not zOk or type(centerZ) ~= "number" then return nil end

    return centerZ + shapeZ / 2
end

local function getTowbarModelSlot(script)
    local frontEdgeZ = getTowbarFrontEdgeZ(script)
    if frontEdgeZ == nil then return nil end

    -- Model offsets position the mesh origin. Move its center outward so the
    -- towbar's inner end, rather than its center, meets the vehicle hitbox.
    local modelCenterZ = frontEdgeZ + TowbarModelHalfLength
    local index = math.floor(((modelCenterZ - TowbarFirstZ) / TowbarSlotStep) + 0.5)
    return math.max(0, math.min(TowbarMaxIndex, index))
end

local function getVehicleModelScale(script)
    if not script then return nil end

    local ok, result = pcall(function()
        return script:getModelScale()
    end)
    if ok and type(result) == "number" then return result end

    ok, result = pcall(function()
        local model = script:getModel()
        return model and model:getScale() or nil
    end)
    if ok and type(result) == "number" then return result end

    return nil
end

local function isVanillaScale(script)
    local modelScale = getVehicleModelScale(script)
    if modelScale == nil then return true end

    local configuredMin = TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMin)
    local configuredMax = TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMax)
    return modelScale >= (configuredMin or VanillaScaleMin)
        and modelScale <= (configuredMax or VanillaScaleMax)
end

local function getTowbarIndexVanilla(script)
    if not script then return nil end
    local ok, shape = pcall(function() return script:getPhysicsChassisShape() end)
    if not ok or not shape then return nil end
    local zOk, shapeZ = pcall(function() return shape:z() end)
    if not zOk or type(shapeZ) ~= "number" then return nil end

    local z = shapeZ / 2 - 0.1
    local index = math.floor((z * 2 / 3 - 1) * 10)
    return math.max(0, math.min(TowbarMaxIndex, index))
end

local function getTowbarIndexSmallScale(script)
    if not script then return nil end

    local maxAbsTowZ = nil
    local trailer = script:getAttachmentById("trailer")
    if trailer then maxAbsTowZ = math.abs(trailer:getOffset():z()) end
    local trailerFront = script:getAttachmentById("trailerfront")
    if trailerFront then
        local frontAbsZ = math.abs(trailerFront:getOffset():z())
        if not maxAbsTowZ or frontAbsZ > maxAbsTowZ then maxAbsTowZ = frontAbsZ end
    end

    if maxAbsTowZ == nil then return nil end
    local index = math.floor((maxAbsTowZ + 0.1 - 1.0) * 10)
    return math.max(0, math.min(TowbarMaxIndex, index))
end

local function getLegacyTowbarModelSlot(script)
    local useNormalPart = isVanillaScale(script)
    local index = getTowbarIndexVanilla(script)
    if not useNormalPart then
        index = getTowbarIndexSmallScale(script) or index
        if index == nil then
            local offset = TowBarMod.Config and tonumber(TowBarMod.Config.smallScaleTowbarIndexOffset) or 2
            index = math.max(0, math.min(TowbarMaxIndex, offset))
        end
    end
    return index, useNormalPart
end

local function setTowBarModelVisible(vehicle, isVisible)
    if not vehicle then return end

    local normalPart = vehicle:getPartById("towbar")
    local largePart = vehicle:getPartById("towbarLarge")
    local ki5Part = vehicle:getPartById("towbarKI5")
    if normalPart == nil and largePart == nil and ki5Part == nil then return end

    for j = 0, TowbarVariantSize - 1 do
        if normalPart then normalPart:setModelVisible("towbar" .. j, false) end
        if largePart then largePart:setModelVisible("towbar" .. j, false) end
        if ki5Part then ki5Part:setModelVisible("towbar" .. j, false) end
    end

    if not isVisible then
        vehicle:doDamageOverlay()
        return
    end

    local script = vehicle:getScript()
    if not script then
        vehicle:doDamageOverlay()
        return
    end

    local isKi5 = TowBarMod.Compatibility.isKi5Vehicle(vehicle)
    local index, useNormalPart
    if isKi5 then
        index = getTowbarModelSlot(script)
    else
        index, useNormalPart = getLegacyTowbarModelSlot(script)
    end

    local part = isKi5 and ki5Part or (useNormalPart and normalPart or largePart)
    if part == nil and not isKi5 then part = normalPart or largePart end
    if part and index ~= nil then
        part:setModelVisible("towbar" .. index, true)
    end

    vehicle:doDamageOverlay()
end

function TowBarMod.Hook.setVehicleScriptWithTowBarHidden(vehicle, scriptName)
    if not vehicle or not scriptName then return false end

    local modData = vehicle:getModData()
    setTowBarModelVisible(vehicle, false)
    if modData then
        modData.towBarModelSwapInProgress = true
    end

    local ok, err = pcall(function()
        vehicle:setScriptName(scriptName)
    end)

    if modData then
        modData.towBarModelSwapInProgress = nil
    end
    -- Script initialization can reset part visibility, so hide it again before
    -- allowing the intended model to be shown by the caller.
    setTowBarModelVisible(vehicle, false)

    if not ok then
        error(err)
    end
    return true
end

local function resolveTowAttachmentsForPair(towingVehicle, towedVehicle, towedModData)
    if not towingVehicle or not towedVehicle then
        return nil, nil
    end

    local attachmentA = towingVehicle:getTowAttachmentSelf() or "trailer"
    local attachmentB = towingVehicle:getTowAttachmentOther()
        or (towedModData and towedModData["towBarChangedAttachmentId"])
        or "trailerfront"

    if not towingVehicle:canAttachTrailer(towedVehicle, attachmentA, attachmentB) then
        if towingVehicle:canAttachTrailer(towedVehicle, "trailer", "trailerfront") then
            attachmentA = "trailer"
            attachmentB = "trailerfront"
        elseif towingVehicle:canAttachTrailer(towedVehicle, "trailerfront", "trailer") then
            attachmentA = "trailerfront"
            attachmentB = "trailer"
        end
    end

    return attachmentA, attachmentB
end

local function isActiveTowBarTowedVehicle(vehicle, modData)
    if not vehicle or not modData then
        return false
    end

    if modData["isTowingByTowBar"] and modData["towed"] then
        return true
    end

    -- Rejoin fallback: if the tow link exists, original-script marker is enough.
    if vehicle:getVehicleTowedBy() and modData.towBarOriginalScriptName ~= nil then
        return true
    end

    return false
end

function TowBarMod.Hook.setVehiclePostAttach(playerObj, towedVehicle, knownTowingVehicle)
    if not towedVehicle then return end

    local towedModData = towedVehicle:getModData()
    if not isActiveTowBarTowedVehicle(towedVehicle, towedModData) then return end

    local towingVehicle = knownTowingVehicle or towedVehicle:getVehicleTowedBy()
    if not towingVehicle then return end

    -- The rigid primitive passes the authoritative towing vehicle because MP
    -- reciprocal getters can lag behind accepted local constraint submission.
    if towedModData and towedModData.towBarOriginalScriptName
            and towedVehicle:getScriptName() ~= towedModData.towBarOriginalScriptName then
        TowBarMod.Hook.setVehicleScriptWithTowBarHidden(towedVehicle, towedModData.towBarOriginalScriptName)
    end

    if towingVehicle then
        local attachmentA, attachmentB = resolveTowAttachmentsForPair(towingVehicle, towedVehicle, towedModData)
        if attachmentA and attachmentB then
            local towingModData = towingVehicle:getModData()
            if towingModData then
                towingModData["towBarTowedVehicleId"] = towedVehicle:getId()
                towingModData["towBarTowingVehicleId"] = nil
                towingModData["towBarExpectedAttachment"] = attachmentA
                towedModData["towBarTowingVehicleId"] = towingVehicle:getId()
                towedModData["towBarTowedVehicleId"] = nil
                towedModData["towBarExpectedAttachment"] = attachmentB
                towingVehicle:transmitModData()
                towedVehicle:transmitModData()
            end
        end
    end

    applyFreeRollingTowState(towedVehicle)

    -- Re-show the towbar model after the script name has been restored.
    -- setScriptName() resets model visibility, so we must set it again here.
    setTowBarModelVisible(towedVehicle, true)
end

function TowBarMod.Hook.performAttachTowBar(playerObj, towingVehicle, towedVehicle, attachmentA, attachmentB)
    if playerObj == nil or towingVehicle == nil or towedVehicle == nil then return end
    if #(TowBarMod.Utils.getHookTypeVariants(towingVehicle, towedVehicle, true)) == 0 then return end

    local towBarItem = getTowBarItem(playerObj)
    if towBarItem == nil then return end
    playerObj:setPrimaryHandItem(nil)

    local args = {
        vehicleA = towingVehicle:getId(),
        vehicleB = towedVehicle:getId(),
        attachmentA = attachmentA,
        attachmentB = attachmentB,
        itemId = towBarItem and towBarItem:getID() or nil
    }
    sendTowAttachCommand(playerObj, args)
end

function TowBarMod.Hook.cleanupDetachedTowBar(towingVehicle, towedVehicle)
    if towingVehicle == nil or towedVehicle == nil then return end

    local towingModData = towingVehicle:getModData()
    local towedModData = towedVehicle:getModData()
    if not towingModData or not towedModData then return end

    if towedModData.towBarOriginalScriptName then
        TowBarMod.Hook.setVehicleScriptWithTowBarHidden(towedVehicle, towedModData.towBarOriginalScriptName)
    end
    -- A very fast break can happen while the temporary fake-trailer script is
    -- still active. Restore the real script first so the saved offsets are
    -- written back to the actual vehicle attachments, not the temporary script.
    TowBarMod.Utils.updateAttachmentsOnDefaultValues(towingVehicle, towedVehicle)
    restoreFreeRollingTowState(towedVehicle, towedModData)

    towingModData["isTowingByTowBar"] = false
    towingModData["towed"] = false
    towingModData["towBarTowedVehicleId"] = nil
    towingModData["towBarTowedVehicleSqlId"] = nil
    towingModData["towBarTowingVehicleId"] = nil
    towingModData["towBarTowingVehicleSqlId"] = nil
    towingModData["towBarExpectedAttachment"] = nil
    towedModData["isTowingByTowBar"] = false
    towedModData["towed"] = false
    towedModData["towBarTowedVehicleId"] = nil
    towedModData["towBarTowedVehicleSqlId"] = nil
    towedModData["towBarTowingVehicleId"] = nil
    towedModData["towBarTowingVehicleSqlId"] = nil
    towedModData["towBarExpectedAttachment"] = nil
    towedModData.towBarOriginalScriptName = nil
    towedModData.towBarOriginalMass = nil
    towedModData.towBarOriginalBrakingForce = nil
    towedModData.towBarOriginalParkingBrakeOn = nil
    towedModData.towBarOriginalParkingBrake = nil
    towedModData.towBarOriginalHandbrake = nil
    towingVehicle:transmitModData()
    towedVehicle:transmitModData()

    setTowBarModelVisible(towedVehicle, false)
end

function TowBarMod.Hook.performDetachTowBar(playerObj, towingVehicle, towedVehicle)
    if playerObj == nil or towingVehicle == nil or towedVehicle == nil then return end

    local args = { towingVehicle = towingVehicle:getId(), vehicle = towedVehicle:getId() }
    sendClientCommand(playerObj, "towbar", "detachTowBar", args)
end

local function forEachCollectionItem(collection, callback)
    if not collection then return end

    local ok, iterator = pcall(function()
        return collection:iterator()
    end)
    if ok and iterator then
        while iterator:hasNext() do
            callback(iterator:next())
        end
        return
    end

    local size
    ok, size = pcall(function()
        return collection:size()
    end)
    if not ok or type(size) ~= "number" then return end

    for i = 0, size - 1 do
        callback(collection:get(i))
    end
end

local function keepTowBarVehiclesFreeRolling()
    freeRollTickCounter = freeRollTickCounter + 1
    if freeRollTickCounter < FreeRollTickInterval then
        return
    end
    freeRollTickCounter = 0

    local cell = getCell()
    if not cell then return end

    local vehicles = cell:getVehicles()
    if not vehicles then return end

    forEachCollectionItem(vehicles, function(vehicle)
        local modData = vehicle and vehicle:getModData() or nil
        if isActiveTowBarTowedVehicle(vehicle, modData) then
            applyFreeRollingTowState(vehicle)
        end
    end)
end

function TowBarMod.Hook.attachByTowBarAction(playerObj, towingVehicle, towedVehicle)
    if playerObj == nil or towingVehicle == nil or towedVehicle == nil then return end

    local item = getTowBarItem(playerObj)
    if item == nil then return end
    if #(TowBarMod.Utils.getHookTypeVariants(towingVehicle, towedVehicle, true)) == 0 then return end

    local hookPoint = towedVehicle:getAttachmentWorldPos("trailerfront", TowBarMod.Utils.tempVector1)
    if hookPoint == nil then return end
    ISTimedActionQueue.add(TowBarCustomPathFind:pathToLocationF(playerObj, hookPoint:x(), hookPoint:y(), hookPoint:z()))

    if not playerObj:getInventory():contains("TowBar.TowBar") then
        ISTimedActionQueue.add(ISInventoryTransferAction:new(playerObj, item, item:getContainer(), playerObj:getInventory(), nil))
    end

    local storePrim = playerObj:getPrimaryHandItem()
    if storePrim == nil or storePrim ~= item then
        ISTimedActionQueue.add(ISEquipWeaponAction:new(playerObj, item, 12, true))
    end

    ISTimedActionQueue.add(TowBarHookVehicle:new(playerObj, 300, TowBarMod.Config.lowLevelAnimation))

    hookPoint = towingVehicle:getAttachmentWorldPos("trailer", TowBarMod.Utils.tempVector1)
    if hookPoint == nil then return end
    ISTimedActionQueue.add(TowBarCustomPathFind:pathToLocationF(playerObj, hookPoint:x(), hookPoint:y(), hookPoint:z()))

    ISTimedActionQueue.add(TowBarHookVehicle:new(
        playerObj,
        100,
        TowBarMod.Config.lowLevelAnimation,
        TowBarMod.Hook.performAttachTowBar,
        towingVehicle,
        towedVehicle,
        "trailer",
        "trailerfront"
    ))
end

function TowBarMod.Hook.deattachTowBarAction(playerObj, vehicle)
    local towingVehicle = vehicle
    local towedVehicle = vehicle and vehicle:getVehicleTowing() or nil
    if vehicle and vehicle:getVehicleTowedBy() then
        towingVehicle = vehicle:getVehicleTowedBy()
        towedVehicle = vehicle
    end
    if towingVehicle == nil or towedVehicle == nil then return end

    local localPoint = towingVehicle:getAttachmentLocalPos(towingVehicle:getTowAttachmentSelf(), TowBarMod.Utils.tempVector1)
    local shift = 0
    if towingVehicle:getModData()["isChangedTowedAttachment"] then
        shift = localPoint:z() > 0 and -1 or 1
    end
    local hookPoint = towingVehicle:getWorldPos(localPoint:x(), localPoint:y(), localPoint:z() + shift, TowBarMod.Utils.tempVector2)
    if hookPoint == nil then return end
    ISTimedActionQueue.add(TowBarCustomPathFind:pathToLocationF(playerObj, hookPoint:x(), hookPoint:y(), hookPoint:z()))

    local storePrim = playerObj:getPrimaryHandItem()
    if storePrim ~= nil then
        ISTimedActionQueue.add(ISUnequipAction:new(playerObj, storePrim, 12))
    end

    ISTimedActionQueue.add(TowBarHookVehicle:new(playerObj, 100, TowBarMod.Config.lowLevelAnimation))

    localPoint = towedVehicle:getAttachmentLocalPos(towedVehicle:getTowAttachmentSelf(), TowBarMod.Utils.tempVector1)
    shift = 0
    if towedVehicle:getModData()["isChangedTowedAttachment"] then
        shift = localPoint:z() > 0 and -1 or 1
    end
    hookPoint = towedVehicle:getWorldPos(localPoint:x(), localPoint:y(), localPoint:z() + shift, TowBarMod.Utils.tempVector2)
    if hookPoint == nil then return end
    ISTimedActionQueue.add(TowBarCustomPathFind:pathToLocationF(playerObj, hookPoint:x(), hookPoint:y(), hookPoint:z()))

    ISTimedActionQueue.add(TowBarHookVehicle:new(
        playerObj,
        300,
        TowBarMod.Config.lowLevelAnimation,
        TowBarMod.Hook.performDetachTowBar,
        towingVehicle,
        towedVehicle
    ))
end

function TowBarMod.Hook.OnSpawnVehicle(vehicle)
    -- Server persistence snapshots own attach recovery after vehicle streaming.
end

function TowBarMod.Hook.OnGameStart()
    -- Server persistence broadcasts the same attach snapshot used by a fresh pair.
end

---------------------------------------------------------------------------
--- Dev / debug helpers
---------------------------------------------------------------------------

function TowBarMod.Hook.devShowAllTowbarModels(playerObj, vehicle)
    if not vehicle then return end
    local normalPart = vehicle:getPartById("towbar")
    local largePart = vehicle:getPartById("towbarLarge")
    local ki5Part = vehicle:getPartById("towbarKI5")
    if normalPart == nil and largePart == nil and ki5Part == nil then
        print("[TowBar DEV] No towbar model part found on vehicle " .. tostring(vehicle:getScriptName()))
        return
    end
    local script = vehicle:getScript()
    local chassisZ = script and script:getPhysicsChassisShape():z() or 0
    local halfZ = chassisZ / 2
    local index = 0
    if script then
        index = getTowbarModelSlot(script)
    end
    local selectedPart = "towbar"
    print("[TowBar DEV] Vehicle: " .. tostring(vehicle:getScriptName()))
    print("[TowBar DEV] chassisShape.z = " .. tostring(chassisZ) .. ", half = " .. tostring(halfZ))
    print("[TowBar DEV] frontEdgeZ = " .. tostring(script and getTowbarFrontEdgeZ(script) or nil) .. ", part = " .. selectedPart)
    print("[TowBar DEV] Formula picks index = " .. tostring(index) .. " (towbar" .. tostring(index) .. " at Z offset " .. tostring(1.0 + index * 0.1) .. ")")
    print("[TowBar DEV] Showing towbar0..towbar23 on all parts")
    for j = 0, TowbarVariantSize - 1 do
        if normalPart then normalPart:setModelVisible("towbar" .. j, true) end
        if largePart then largePart:setModelVisible("towbar" .. j, true) end
        if ki5Part then ki5Part:setModelVisible("towbar" .. j, true) end
    end
    vehicle:doDamageOverlay()
end

function TowBarMod.Hook.devHideAllTowbarModels(playerObj, vehicle)
    if not vehicle then return end
    local normalPart = vehicle:getPartById("towbar")
    local largePart = vehicle:getPartById("towbarLarge")
    local ki5Part = vehicle:getPartById("towbarKI5")
    if normalPart == nil and largePart == nil and ki5Part == nil then
        print("[TowBar DEV] No towbar model part found on vehicle " .. tostring(vehicle:getScriptName()))
        return
    end
    print("[TowBar DEV] Hiding ALL towbar models on " .. tostring(vehicle:getScriptName()))
    for j = 0, TowbarVariantSize - 1 do
        if normalPart then normalPart:setModelVisible("towbar" .. j, false) end
        if largePart then largePart:setModelVisible("towbar" .. j, false) end
        if ki5Part then ki5Part:setModelVisible("towbar" .. j, false) end
    end
    vehicle:doDamageOverlay()
end

function TowBarMod.Hook.devShowSingleTowbar(playerObj, vehicle, index)
    if not vehicle then return end
    local normalPart = vehicle:getPartById("towbar")
    local largePart = vehicle:getPartById("towbarLarge")
    local ki5Part = vehicle:getPartById("towbarKI5")
    if normalPart == nil and largePart == nil and ki5Part == nil then
        print("[TowBar DEV] No towbar model part found on vehicle " .. tostring(vehicle:getScriptName()))
        return
    end

    local localIndex = math.max(0, math.min(TowbarMaxIndex, index % TowbarVariantSize))
    local selectedPartId = "towbar"
    if index >= TowbarVariantSize * 2 then
        selectedPartId = "towbarKI5"
    elseif index >= TowbarVariantSize then
        selectedPartId = "towbarLarge"
    end

    for j = 0, TowbarVariantSize - 1 do
        if normalPart then normalPart:setModelVisible("towbar" .. j, false) end
        if largePart then largePart:setModelVisible("towbar" .. j, false) end
        if ki5Part then ki5Part:setModelVisible("towbar" .. j, false) end
    end

    local part = selectedPartId == "towbarKI5" and ki5Part
        or (selectedPartId == "towbarLarge" and largePart or normalPart)
    if part == nil then
        part = normalPart or largePart or ki5Part
    end
    print("[TowBar DEV] Showing only towbar" .. tostring(localIndex) .. " on part " .. selectedPartId .. " (Z offset " .. tostring(1.0 + localIndex * 0.1) .. ") on " .. tostring(vehicle:getScriptName()))
    if part then
        part:setModelVisible("towbar" .. localIndex, true)
    end
    vehicle:doDamageOverlay()
end

Events.OnSpawnVehicleEnd.Add(TowBarMod.Hook.OnSpawnVehicle)
if Events.OnGameStart then
    Events.OnGameStart.Add(TowBarMod.Hook.OnGameStart)
end
Events.OnTick.Add(keepTowBarVehiclesFreeRolling)