[Lua] Working Anti-Cheat script

PLUGIN_NAME = "Basic Anti-Cheat for AssaultCube"
PLUGIN_AUTHOR = "UKnowMe?"
PLUGIN_VERSION = "1.0.1"

local configuration = {
    ban_time = 1200000
}
-- values taken from server.h.cpp, will probably break in next release
-- format: refill_size, max_reserve, magsize
local guninfo = {
    [GUN_KNIFE]   = {  1,  1,  1},
    [GUN_PISTOL]  = { 20,100, 10},
    [GUN_CARBINE] = { 15, 30, 10},
    [GUN_SHOTGUN] = { 14, 21,  7},
    [GUN_SUBGUN]  = { 60, 90, 30},
    [GUN_SNIPER]  = { 10, 15,  5},
    [GUN_ASSAULT] = { 40, 60, 20},
    [GUN_CPISTOL] = { 30, 75, 15},
    [GUN_GRENADE] = {  1,  3,  1},
    [GUN_AKIMBO]  = {100,100, 20}
}
local player_information = {}

-- helper functions

function banclient(cn, reason)
    clientprint(-1, "\f3Player " .. getname(cn) .. " has " .. reason .. ", auto-banning " .. getip(cn))
    logline(ACLOG_INFO, reason .. " detected on player " .. getname(cn) .. " auto-banning...")
    ban(cn, configuration['ban_time'], BAN_AUTO)
end

-- handlers

function onInit()
    for cn in players(true) do
        onPlayerSpawn(cn)
        onPlayerWeaponChange(cn, getweapon(cn))
        player_information[cn]['nades'] = getammo(GUN_GRENADE)
    end
end

function onPlayerSpawn(cn)
    player_information[cn] = {
        nades = 0,
        akimbo = false,
        ammo = {}
    }
end

function onPlayerWeaponChange(cn, weapon)
    if weapon ~= GUN_KNIFE and weapon ~= GUN_GRENADE then
        if player_information[cn]['ammo'][weapon] == nil or next(player_information[cn]['ammo'][weapon]) == nil then
            player_information[cn]['ammo'][weapon] = {}
            player_information[cn]['ammo'][weapon]['reserve'], player_information[cn]['ammo'][weapon]['mag'] = getammo(cn, weapon)
        end
    end
end

function onPlayerShoot(cn, gun, to)
    if gun == GUN_GRENADE then
        if player_information[cn]['nades'] == 0 then
            banclient(cn, 'nadehack')
        else
            player_information[cn]['nades'] = player_information[cn]['nades'] - 1
        end
    end
end

function onPlayerShootAfter(cn, gun, to)
    if gun ~= GUN_KNIFE and gun ~= GUN_GRENADE then
        local reserve, mag = getammo(cn, gun)
        if player_information[cn]['ammo'][gun]['mag'] == 0 then
            banclient(cn, 'ammohack')
        else
            player_information[cn]['ammo'][gun]['mag'] = player_information[cn]['ammo'][gun]['mag'] - 1
        end
    end
end

function onPlayerItemPickup(cn, item_type, item_id)
    if item_type == I_GRENADE then
        player_information[cn]['nades'] = math.min(player_information[cn]['nades'] + (getgamemode() == GM_LSS and 2 or 1), guninfo[GUN_GRENADE][2])
    elseif item_type == I_AMMO then
        local gun = getprimary(cn)
        local info = guninfo[gun]
        player_information[cn]['ammo'][gun]['reserve'] = math.min(player_information[cn]['ammo'][gun]['reserve'] + info[1], info[2])
    elseif item_type == I_CLIPS then
        local gun = player_information[cn]['akimbo'] and GUN_AKIMBO or GUN_PISTOL
        local info = guninfo[gun]
        player_information[cn]['ammo'][gun]['reserve'] = math.min(player_information[cn]['ammo'][gun]['reserve'] + info[1], info[2])
    end
end

function onPlayerWeaponReload(cn, gun)
    if player_information[cn]['ammo'][gun]['reserve'] == 0 then
        banclient(cn, 'ammohack')
    end

    local current = player_information[cn]['ammo'][gun]['mag']
    local info = guninfo[gun]
    local fill = math.min(info[3] - current, player_information[cn]['ammo'][gun]['reserve'])
    player_information[cn]['ammo'][gun]['mag'] = player_information[cn]['ammo'][gun]['mag'] + fill
    player_information[cn]['ammo'][gun]['reserve'] = player_information[cn]['ammo'][gun]['reserve'] - fill
end

function clearAkimbo(timerid)
    player_information[timerid]['akimbo'] = false
end

function onPlayerGetAkimbo(cn)
    player_information[cn]['akimbo'] = true
    tmr.after(cn, 30000, clearAkimbo)
end

function onPlayerDisconnect(cn, reason)
    player_information[cn] = nil
    tmr.remove(cn)
end