local hook=require("hooks")

local function vtable_bind(module, interface, index, type)
    local addr = ffi.cast("void***", utils.find_interface(module, interface)) or error(interface .. " is nil.")
    return ffi.cast(ffi.typeof(type), addr[0][index]), addr
end

local function __thiscall(func, this)
    return function(...)
        return func(this, ...)
    end
end

local function vtable_thunk(index, typestring)
    local t = ffi.typeof(typestring)
    return function(instance, ...)
        assert(instance ~= nil)
        if instance then
            local addr=ffi.cast("void***", instance)
            return __thiscall(ffi.cast(t, (addr[0])[index]),addr)
        end
    end
end

local cheat_refs = {
    fast_fire_ref = gui.get_config_item("rage>aimbot>aimbot>double tap"),
    anti_exploit = gui.get_config_item("rage>aimbot>aimbot>anti-exploit")
}

local menu_elements = {
    enable_ping = gui.add_checkbox("Ping Spike", "Lua>Tab A"),
    bind_ping = gui.add_keybind("Lua>Tab A>Ping Spike"),
    ping_amount = gui.add_slider("Amount", "Lua>Tab A", 5, 180, 1) -- increase at own risk, anything above this value causes inaccuracy issues.
}

ffi.cdef[[
    typedef struct
    {
        char   pad0[0x14];             //0x0000
        bool        bProcessingMessages;    //0x0014
        bool        bShouldDelete;          //0x0015
        char   pad1[0x2];              //0x0016
        int         iOutSequenceNr;         //0x0018 last send outgoing sequence number
        int         iInSequenceNr;          //0x001C last received incoming sequence number
        int         iOutSequenceNrAck;      //0x0020 last received acknowledge outgoing sequence number
        int         iOutReliableState;      //0x0024 state of outgoing reliable data (0/1) flip flop used for loss detection
        int         iInReliableState;       //0x0028 state of incoming reliable data
        int         iChokedPackets;         //0x002C number of choked packets
        char   pad2[0x414];            //0x0030
    } INetChannel; // Size: 0x0444
]]

local nullptr = ffi.new('void*')

local nativeGetNetChannel = __thiscall(vtable_bind("engine.dll", "VEngineClient014", 78, "INetChannel*(__thiscall*)(void*)"))

local INetChannelPtr=nullptr

local nativeINetMessageGetType=vtable_thunk(7,"int(__thiscall*)(void*)")
local nativeINetChannelGetLatency=vtable_thunk(9,"float(__thiscall*)(void*,int)")

local vecSequences={}
local nLastIncomingSequence=0

local function UpdateIncomingSequences(pNetChannel)
        if nLastIncomingSequence==0 then nLastIncomingSequence=pNetChannel.iInSequenceNr end
        if pNetChannel.iInSequenceNr > nLastIncomingSequence then
            nLastIncomingSequence=pNetChannel.iInSequenceNr
            table.insert(vecSequences,1,{pNetChannel.iInReliableState,pNetChannel.iChokedPackets,pNetChannel.iInSequenceNr,global_vars.realtime})
        end
        if #vecSequences > 128 then
            table.remove(vecSequences)
        end
    end

local function ClearIncomingSequences()
    nLastIncomingSequence=0
    if #vecSequences~=0 then
        vecSequences={}
    end
end

function SendDatagramHook(originalFunction)
    local originalFunction=originalFunction
    local sv_maxunlag = cvar["sv_maxunlag"]

    function clamp(min, max, value)
        return math.min(math.max(min, value), max)
    end

    function AddLatencyToNetChannel(pNetChannel,flMaxLatency)
        for i,sequence in ipairs(vecSequences) do
            if global_vars.realtime-sequence[4]>=flMaxLatency then
                pNetChannel.iInReliableState=sequence[1]
                pNetChannel.iInSequenceNr=sequence[3]
                break
            end
        end
    end

    function SendDatagram(this,pDatagram)
        local local_player = entities.get_entity(engine.get_local_player())
        if not engine.is_in_game() or not local_player:is_valid() or not menu_elements.enable_ping:get_bool() or cheat_refs.anti_exploit:get_bool() or pDatagram~=nullptr then
            return originalFunction(this,pDatagram)
        end

        local iOldInReliableState=this.iInReliableState
        local iOldInSequenceNr=this.iInSequenceNr

        local flMaxLatency=math.max(0,clamp(0,sv_maxunlag:get_float(),menu_elements.ping_amount:get_int()/1000)-nativeINetChannelGetLatency(this)(0))
        AddLatencyToNetChannel(this,flMaxLatency)

        local res=originalFunction(this,pDatagram)

        this.iInReliableState=iOldInReliableState
        this.iInSequenceNr=iOldInSequenceNr

        return res
    end
    return SendDatagram
end

local INetChannel

local initialize=false

function on_setup_move(cmd)
    INetChannelPtr=nativeGetNetChannel()
    if menu_elements.enable_ping:get_bool() then
        UpdateIncomingSequences(INetChannelPtr)
    else
        ClearIncomingSequences()
    end
    if initialize then return end
    initialize=true
    INetChannel=hook.jmp.new("int(__thiscall*)(INetChannel*,void*)",SendDatagramHook,ffi.cast("intptr_t**",INetChannelPtr)[0][46],6,true)
end

function on_frame_stage_notify(stage, pre_original)
    if engine.is_in_game() then return end
    ClearIncomingSequences()
end

function on_shutdown()
    if INetChannel~=nil then INetChannel.stop() end
end

local function handle_visiblity()
    if menu_elements.enable_ping:get_bool() then
        gui.set_visible("Lua>Tab A>Amount", true)
    else
        gui.set_visible("Lua>Tab A>Amount", false)
    end
end

function on_paint()
    handle_visiblity()
    local local_player = entities.get_entity(engine.get_local_player())
    if not engine.is_in_game() or not local_player:is_valid() or not menu_elements.enable_ping:get_bool() then
        return
    end
end