local entity_get_local_player, entity_get_prop, bit_band, ui_get, math_abs = entity.get_local_player, entity.get_prop, bit.band, ui.get, math.abs
local FL_ONGROUND = 1
local MOVETYPE_LADDER = 9
local yaw_prev, onground_prev = nil, false

--bypasses https://github.com/eedson/Cow-Anti-Cheat/blob/master/CowAntiCheat.sp#L810-L868
local turn_right_prev = false

local function flag_set(flag, player)
	local player = player ~= nil and player or entity_get_local_player()
	if player == nil then
		return false
	end
	local flags = entity_get_prop(player, "m_fFlags")
	if flags == nil then
		return false
	end

	return bit_band(flags, flag) == flag
end

local enabled_reference = ui.new_checkbox("MISC", "Miscellaneous", "Legit air strafe")
local hotkey_reference = ui.new_hotkey("MISC", "Miscellaneous", "Legit air strafe hotkey", true)

client.set_event_callback("setup_command", function(cmd)
	if not ui_get(enabled_reference) then
		return
	end

	local onground = flag_set(FL_ONGROUND)
	if ui_get(hotkey_reference) and (not onground or not onground_prev) then
		if cmd.in_moveleft == 0 and cmd.in_moveright == 0 and cmd.in_speed == 0 and entity_get_prop(entity_get_local_player(), "m_MoveType") ~= MOVETYPE_LADDER then
			if yaw_prev ~= nil and (math_abs(cmd.yaw-yaw_prev) > 0.02) then
				cmd.in_forward = 0
				local turn_right = cmd.yaw < yaw_prev
				if turn_right or turn_right_prev then
					cmd.in_moveright = 1
					if turn_right then
						cmd.sidemove = 450
					end
				end
				if not turn_right or not turn_right_prev then
					cmd.in_moveleft = 1
					if not turn_right then
						cmd.sidemove = -450
					end
				end
				turn_right_prev = turn_right

				if cmd.in_back == 1 then
					cmd.in_moveright, cmd.in_moveleft = cmd.in_moveleft, cmd.in_moveright
					cmd.sidemove = cmd.sidemove * -1
				end

				--client.log("moveleft=", cmd.in_moveleft, " moveright=", cmd.in_moveright)
			end
		end
	end
	yaw_prev, onground_prev = cmd.yaw, onground
end)