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

local TowBarTowMass = 200
local AutoReattachCooldownHours = 1 / 7200 -- 0.5 seconds
TowBarMod.Hook.lastAutoReattachAtByVehicle = TowBarMod.Hook.lastAutoReattachAtByVehicle or {}
local AutoReattachPlayerCooldownHours = 1 / 14400 -- 0.25 seconds
TowBarMod.Hook.lastAutoReattachAtByPlayer = TowBarMod.Hook.lastAutoReattachAtByPlayer or {}

local function isTowBarTowPair(towingVehicle, towedVehicle)
    if not towingVehicle or not towedVehicle then return false end

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

    if towingModData["isTowingByTowBar"] and towedModData["isTowingByTowBar"] and towedModData["towed"] then
        return true
    end

    -- Rejoin fallback: original towbar state on the towed vehicle is enough to reapply rigid spacing.
    if towedModData.towBarOriginalScriptName ~= nil then
        return true
    end

    return false
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 setTowBarModelVisible(vehicle, isVisible)
    if not vehicle then return end

    local part = vehicle:getPartById("towbar")
    if part == nil then return end

    for j = 0, 23 do
        part:setModelVisible("towbar" .. j, false)
    end

    if not isVisible then
        vehicle:doDamageOverlay()
        return
    end

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

    local scale = script:getModelScale()
    if scale >= 1.5 and scale <= 2 then
        local z = script:getPhysicsChassisShape():z()/2 - 0.1
        part:setModelVisible("towbar" .. math.floor((z*2/3 - 1)*10), true)
    end

    vehicle:doDamageOverlay()
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 hasTowBarTowState(modData)
    if not modData then
        return false
    end

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

    -- Rejoin fallback: legacy saves may only have the original-script marker.
    if modData.towBarOriginalScriptName ~= nil then
        return true
    end

    return false
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

local function reattachTowBarPair(playerObj, towingVehicle, towedVehicle, requireDriver)
    if not playerObj or not towingVehicle or not towedVehicle then
        return false
    end
    if requireDriver and not towingVehicle:isDriver(playerObj) then
        return false
    end

    local towingModData = towingVehicle:getModData()
    local towedModData = towedVehicle:getModData()
    if not towingModData or not towedModData then
        return false
    end
    if requireDriver then
        if not isTowBarTowPair(towingVehicle, towedVehicle) then
            return false
        end
    else
        if not isActiveTowBarTowedVehicle(towedVehicle, towedModData) then
            return false
        end
    end

    local attachmentA, attachmentB = resolveTowAttachmentsForPair(towingVehicle, towedVehicle, towedModData)
    if not attachmentA or not attachmentB then
        return false
    end

    local towingScript = towingVehicle:getScript()
    local towedScript = towedVehicle:getScript()
    if not towingScript or not towedScript then
        return false
    end
    if not towingScript:getAttachmentById(attachmentA) or not towedScript:getAttachmentById(attachmentB) then
        return false
    end

    TowBarMod.Utils.updateAttachmentsForRigidTow(towingVehicle, towedVehicle, attachmentA, attachmentB)

    towedModData.towBarOriginalScriptName = towedModData.towBarOriginalScriptName or towedVehicle:getScriptName()
    if towedModData.towBarOriginalMass == nil then
        towedModData.towBarOriginalMass = towedVehicle:getMass()
    end
    if towedModData.towBarOriginalBrakingForce == nil then
        towedModData.towBarOriginalBrakingForce = towedVehicle:getBrakingForce()
    end

    towingModData["isTowingByTowBar"] = true
    towedModData["isTowingByTowBar"] = true
    towedModData["towed"] = true
    towingVehicle:transmitModData()
    towedVehicle:transmitModData()

    setTowBarModelVisible(towedVehicle, true)
    towedVehicle:setScriptName("notTowingA_Trailer")

    local args = {
        vehicleA = towingVehicle:getId(),
        vehicleB = towedVehicle:getId(),
        attachmentA = attachmentA,
        attachmentB = attachmentB
    }
    sendClientCommand(playerObj, "vehicle", "attachTrailer", args)
    ISTimedActionQueue.add(TowBarScheduleAction:new(playerObj, 10, TowBarMod.Hook.setVehiclePostAttach, towedVehicle))
    return true
end

local function recoverTowBarVehicleAfterLoad(playerObj, vehicle, retriesLeft)
    if not vehicle then return end

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

    local retries = tonumber(retriesLeft) or 0
    local localPlayer = playerObj or getPlayer()
    local towingVehicle = vehicle:getVehicleTowedBy()

    if localPlayer and towingVehicle then
        if reattachTowBarPair(localPlayer, towingVehicle, vehicle, false) then
            return
        end
    end

    if localPlayer and retries > 0 then
        -- During world load, tow links can become available a few ticks later.
        ISTimedActionQueue.add(TowBarScheduleAction:new(localPlayer, 10, recoverTowBarVehicleAfterLoad, vehicle, retries - 1))
        return
    end

    -- Fallback: keep original post-attach restoration behavior.
    setTowBarModelVisible(vehicle, true)
    TowBarMod.Hook.setVehiclePostAttach(nil, vehicle)
end

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

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

    if towedModData and towedModData.towBarOriginalScriptName then
        towedVehicle:setScriptName(towedModData.towBarOriginalScriptName)
    end

    local towingVehicle = towedVehicle:getVehicleTowedBy()
    if towingVehicle then
        local attachmentA, attachmentB = resolveTowAttachmentsForPair(towingVehicle, towedVehicle, towedModData)
        if attachmentA and attachmentB then
            TowBarMod.Utils.updateAttachmentsForRigidTow(towingVehicle, towedVehicle, attachmentA, attachmentB)
        end
    end

    towedVehicle:setMass(TowBarTowMass)
    towedVehicle:setBrakingForce(0)
    towedVehicle:constraintChanged()
    towedVehicle:updateTotalMass()
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
        sendClientCommand(playerObj, "towbar", "consumeTowBar", { itemId = towBarItem:getID() })
    end
    playerObj:setPrimaryHandItem(nil)

    TowBarMod.Utils.updateAttachmentsForRigidTow(towingVehicle, towedVehicle, attachmentA, attachmentB)

    local towingModData = towingVehicle:getModData()
    local towedModData = towedVehicle:getModData()

    towedModData.towBarOriginalScriptName = towedVehicle:getScriptName()
    towedModData.towBarOriginalMass = towedVehicle:getMass()
    towedModData.towBarOriginalBrakingForce = towedVehicle:getBrakingForce()

    towingModData["isTowingByTowBar"] = true
    towedModData["isTowingByTowBar"] = true
    towedModData["towed"] = true
    towingVehicle:transmitModData()
    towedVehicle:transmitModData()

    setTowBarModelVisible(towedVehicle, true)

    -- Match the known-good rigid tow path: fake trailer + vanilla attach command.
    towedVehicle:setScriptName("notTowingA_Trailer")

    local args = {
        vehicleA = towingVehicle:getId(),
        vehicleB = towedVehicle:getId(),
        attachmentA = attachmentA,
        attachmentB = attachmentB
    }
    sendClientCommand(playerObj, "vehicle", "attachTrailer", args)
    ISTimedActionQueue.add(TowBarScheduleAction:new(playerObj, 10, TowBarMod.Hook.setVehiclePostAttach, towedVehicle))
end

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

    TowBarMod.Utils.updateAttachmentsOnDefaultValues(towingVehicle, towedVehicle)

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

    local towedModData = towedVehicle:getModData()
    if towedModData.towBarOriginalScriptName then
        towedVehicle:setScriptName(towedModData.towBarOriginalScriptName)
    end
    if towedModData.towBarOriginalMass ~= nil then
        towedVehicle:setMass(towedModData.towBarOriginalMass)
    end
    if towedModData.towBarOriginalBrakingForce ~= nil then
        towedVehicle:setBrakingForce(towedModData.towBarOriginalBrakingForce)
    end
    towedVehicle:constraintChanged()
    towedVehicle:updateTotalMass()

    sendClientCommand(playerObj, "towbar", "giveTowBar", { equipPrimary = true })

    local towingModData = towingVehicle:getModData()
    towingModData["isTowingByTowBar"] = false
    towedModData["isTowingByTowBar"] = false
    towedModData["towed"] = false
    towedModData.towBarOriginalScriptName = nil
    towedModData.towBarOriginalMass = nil
    towedModData.towBarOriginalBrakingForce = nil
    towingVehicle:transmitModData()
    towedVehicle:transmitModData()

    TowBarMod.Hook.lastAutoReattachAtByVehicle[towingVehicle:getId()] = nil

    setTowBarModelVisible(towedVehicle, false)
end

function TowBarMod.Hook.reattachTowBarFromDriverSeat(playerObj, towingVehicle)
    if not playerObj or not towingVehicle then return end

    local towedVehicle = towingVehicle:getVehicleTowing()
    if not towedVehicle then return end

    reattachTowBarPair(playerObj, towingVehicle, towedVehicle, true)
end

local function tryAutoReattachFromCharacter(character)
    if not character or not instanceof(character, "IsoPlayer") or not character:isLocalPlayer() then return end

    local playerObj = character
    local nowHours = getGameTime() and getGameTime():getWorldAgeHours() or 0
    local playerNum = playerObj:getPlayerNum()
    local lastPlayerHours = TowBarMod.Hook.lastAutoReattachAtByPlayer[playerNum]
    if lastPlayerHours and (nowHours - lastPlayerHours) < AutoReattachPlayerCooldownHours then
        return
    end

    local towingVehicle = playerObj:getVehicle()
    if not towingVehicle then return end
    if not towingVehicle:isDriver(playerObj) then return end
    local towedVehicle = towingVehicle:getVehicleTowing()
    if not towedVehicle then return end
    if not isTowBarTowPair(towingVehicle, towedVehicle) then return end

    local vehicleId = towingVehicle:getId()
    local lastHours = TowBarMod.Hook.lastAutoReattachAtByVehicle[vehicleId]
    if lastHours and (nowHours - lastHours) < AutoReattachCooldownHours then
        return
    end

    TowBarMod.Hook.lastAutoReattachAtByPlayer[playerNum] = nowHours
    TowBarMod.Hook.lastAutoReattachAtByVehicle[vehicleId] = nowHours
    TowBarMod.Hook.reattachTowBarFromDriverSeat(playerObj, towingVehicle)
end

function TowBarMod.Hook.OnEnterVehicle(character)
    tryAutoReattachFromCharacter(character)
end

function TowBarMod.Hook.OnSwitchVehicleSeat(character)
    tryAutoReattachFromCharacter(character)
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)
    recoverTowBarVehicleAfterLoad(nil, vehicle, 6)
end

function TowBarMod.Hook.OnGameStart()
    local cell = getCell()
    if not cell then return end

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

    local playerObj = getPlayer()
    for i = 0, vehicles:size() - 1 do
        recoverTowBarVehicleAfterLoad(playerObj, vehicles:get(i), 6)
    end
end

Events.OnSpawnVehicleEnd.Add(TowBarMod.Hook.OnSpawnVehicle)
if Events.OnGameStart then
    Events.OnGameStart.Add(TowBarMod.Hook.OnGameStart)
end
Events.OnEnterVehicle.Add(TowBarMod.Hook.OnEnterVehicle)
Events.OnSwitchVehicleSeat.Add(TowBarMod.Hook.OnSwitchVehicleSeat)