--- This script allows the player to fly, as if they were in creative mode. Be warned, this isn't perfect, and lag may
--- result in your death.

--- Firstly we want to ensure that we have a neural interface and wrap it.
local modules = peripheral.find("neuralInterface")
if not modules then
	error("Must have a neural interface", 0)
end

--- - We require a sensor and introspection module in order to gather information about the player
--- - The sensor is used to determine where the ground is relative to the player, meaning we can slow the player
---   before they hit the floor.
--- - The kinetic augment is (obviously) used to launch the player.
if not modules.hasModule("plethora:sensor") then error("Must have a sensor", 0) end
if not modules.hasModule("plethora:scanner") then error("Must have a scanner", 0) end
if not modules.hasModule("plethora:introspection") then error("Must have an introspection module", 0) end
if not modules.hasModule("plethora:kinetic", 0) then error("Must have a kinetic agument", 0) end

--- We run several loop at once, to ensure that various components do not delay each other.
local meta = {}
local hover = false
parallel.waitForAny(
	--- This loop just pulls user input. It handles a couple of function keys, as well as
	--- setting the "hover" field to true/false.
	---
	--- We recommend running [with the keyboard in your neural interface](../items/keyboard.html#using-with-the-neural-interface),
	--- as this allows you to navigate without having the interface open.
	function()
		while true do
			local event, key = os.pullEvent()
			if event == "key" and key == keys.o then
				-- The O key launches you high into the air.
				modules.launch(0, -90, 3)
			elseif event == "key" and key == keys.p then
				-- The P key launches you a little into the air.
				modules.launch(0, -90, 1)
			elseif event == "key" and key == keys.l then
				-- The l key launches you in whatever direction you are looking.
				modules.launch(meta.yaw, meta.pitch, 3)
			elseif event == "key" and key == keys.k then
				-- Holding the K key enables "hover" mode. We disable it when it is released.
				if not hover then
					hover = true
					os.queueEvent("hover")
				end
			elseif event == "key_up" and key == keys.k then
				hover = false
			end
		end
	end,
	--- Continuously update the metadata. We do this in a separate loop to ensure this doesn't delay
	--- other functions
	function()
		while true do
			meta = modules.getMetaOwner()
		end
	end,
	--- If we are hovering then attempt to catapult us back into air, with sufficient velocity to
	--- just counteract gravity.
	function()
		while true do
			if hover then
				-- We calculate the required motion we need to take
				local mY = meta.motionY
				mY = (mY - 0.138) / 0.8

				-- If it is sufficiently large then we fire ourselves in that direction.
				if mY > 0.5 or mY < 0 then
					local sign = 1
					if mY < 0 then sign = -1 end
					modules.launch(0, 90 * sign, math.min(4, math.abs(mY)))
				else
					sleep(0)
				end
			else
				os.pullEvent("hover")
			end
		end
	end,
	--- If we can detect a block below us, and we're falling sufficiently fast, then attempt to slow our fall. This
	---needs to react as fast as possible, so we can't call many peripheral methods here.
	function()
		while true do
			local blocks = modules.scan()
			for y = 0, -8, -1 do
				-- Scan from the current block downwards
				local block = blocks[1 + (8 + (8 + y)*17 + 8*17^2)]
				if block.name ~= "minecraft:air" then
					if meta.motionY < -0.3 then
						-- If we're moving slowly, then launch ourselves up
						modules.launch(0, -90, math.min(4, meta.motionY / -0.5))
					end
					break
				end
			end
		end
	end
)