BTtow = {}
BTtow.Create = {}
BTtow.Init = {}

local TowbarVariantSize = 24
local TowbarNormalStart = 0
local TowbarLargeStart = 24
local TowbarMaxIndex = TowbarVariantSize - 1
local VanillaScaleMin = 1.5
local VanillaScaleMax = 2.0

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()
        if model then
            return model:getScale()
        end
        return 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 and TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMin)
    local configuredMax = TowBarMod and TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMax)
    local minScale = configuredMin or VanillaScaleMin
    local maxScale = configuredMax or VanillaScaleMax
    return modelScale >= minScale and modelScale <= maxScale
end

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

local function getTowbarModelSlot(script)
    if not isVanillaScale(script) then
        -- KI5/small-scale vehicles use the normal towbar0 mesh at Z=1.
        return 0
    end
    return getTowbarIndexVanilla(script)
end

function BTtow.Create.towbar(vehicle, part)  
    if part == nil then return end
    for j=0, TowbarVariantSize - 1 do
        part:setModelVisible("towbar" .. j, false)        
    end
end

function BTtow.Init.towbar(vehicle, part)
    if part == nil then return end
    for j=0, TowbarVariantSize - 1 do
        part:setModelVisible("towbar" .. j, false)
    end
    local modData = vehicle:getModData()
    if modData and modData.towBarModelSwapInProgress then
        return
    end
    if modData and modData["isTowingByTowBar"] and modData["towed"] then
        local script = vehicle:getScript()
        if script then
            local index = getTowbarModelSlot(script)
            local shouldShowOnThisPart = part:getId() == "towbar"
            if shouldShowOnThisPart then
                part:setModelVisible("towbar" .. index, true)
            end
        end
    end
end