minetest.register_craftitem("turtle_miner:remotecontrol", {
	description = "A remote control for Miner-Turtles",
	inventory_image = "turtle_miner_remotecontrol.png",
})

local turtle_formspec_positions = {}

minetest.register_node("turtle_miner:firstturtle", {
	description = "First Turtle for Trials",
	tiles = {"turtle_miner_firstturtle_top.png", "turtle_miner_firstturtle_buttom.png", "turtle_miner_firstturtle_right.png", "turtle_miner_firstturtle_left.png", "turtle_miner_firstturtle_back.png", "turtle_miner_firstturtle_front.png"},
	groups={oddly_breakable_by_hand=1},
	paramtype2 = "facedir",
	
	on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
		local wielditem = clicker:get_wielded_item()
		local wieldname = wielditem:get_name()
		if wieldname ~= "turtle_miner:remotecontrol" then
			minetest.chat_send_player(clicker:get_player_name(), "Nimm die Fernbedienung!")
		else
			-- When the player does a right click on this node
			local player_name = clicker:get_player_name()
			 -- Save the last turtle in a table
			turtle_formspec_positions[player_name] = pos
		
			minetest.show_formspec(player_name, "turtle_miner:control_formspec", 
				"size[9,4]" ..
				"label[0,0;Click buttons to move the turtle around!]" ..
				"button_exit[5,1;2,1;exit;Exit]" ..
				"image_button[1,1;1,1;arrow_up.png;up;]" ..
				"image_button[2,1;1,1;arrow_fw.png;forward;]" ..
				"button[3,1;1,1;dig;dig]" ..
				"image_button[1,2;1,1;arrow_left.png;turnleft;]"..
				"image_button[3,2;1,1;arrow_right.png;turnright;]" ..
				"image_button[1,3;1,1;arrow_down.png;down;]" ..
				"image_button[2,3;1,1;arrow_bw.png;backward;]"
				--.. "button[3,3;1,1;build;build]"
				)
			return itemstack
		  
		end
		
	end,
})

local function nextrangeright(x)
	x = x + 1
	if x > 3 then
		x = 0
	end
	return x
end

local function nextrangeleft(x)
	x = x - 1
	if x < 0 then
		x = 3
	end
	return x
end

-- Catch user inputs from the formspec
minetest.register_on_player_receive_fields(function(sender, formname, fields)
	if formname ~= "turtle_miner:control_formspec" then
		return -- Not a turtle formspec
	end
	local player_name = sender:get_player_name()
	local pos = turtle_formspec_positions[player_name]
   
	if not pos then
		return -- Something went wrong. No position found for this player
	end
   
	local node = minetest.get_node(pos)
	
	if node.name ~= "turtle_miner:firstturtle" then
		turtle_formspec_positions[player_name] = nil
		return -- Data invalid. There's no turtle at the given position
	end
   
	local new_pos = vector.new(pos)
	local dig_pos = vector.new(pos)
	
	local dir = minetest.facedir_to_dir(node.param2)
	local dirx= dir.x
	local dirz= dir.z
	local move = false
	
	if fields.up then
		new_pos.y = new_pos.y + 1
		move = true
	end
   
	if fields.down then
		new_pos.y = new_pos.y - 1
		move = true
	end
   
	if fields.forward then
		new_pos.z = new_pos.z - dirz
		new_pos.x = new_pos.x - dirx
		move = true
	end
   
	if fields.backward then
		new_pos.z = new_pos.z + dirz
		new_pos.x = new_pos.x + dirx
		move = true
	end
	
	if fields.turnright then
		local ndef = minetest.registered_nodes[node.name]

		-- Compute param2
		local rotationPart = node.param2 % 32 -- get first 4 bits
		local preservePart = node.param2 - rotationPart
		local axisdir = math.floor(rotationPart / 4)
		local rotation = rotationPart - axisdir * 4
		rotationPart = axisdir * 4 + nextrangeright(rotation)
		
		local new_param2 = preservePart + rotationPart
		
		node.param2 = new_param2
		minetest.swap_node(pos, node)
		move = false
		minetest.sound_play("moveokay", {to_player = player_name,gain = 1.0,})
		return
	end

	if fields.turnleft then
		local ndef = minetest.registered_nodes[node.name]

		-- Compute param2
		local rotationPart = node.param2 % 32 -- get first 4 bits
		local preservePart = node.param2 - rotationPart
		local axisdir = math.floor(rotationPart / 4)
		local rotation = rotationPart - axisdir * 4
		rotationPart = axisdir * 4 + nextrangeleft(rotation)
		
		local new_param2 = preservePart + rotationPart
		
		node.param2 = new_param2
		minetest.swap_node(pos, node)
		move = false
		minetest.sound_play("moveokay",{to_player = player_name,gain = 1.0,})
		return
	end	

	-- Check new position if empty
	local newposchecktable = minetest.get_node(new_pos)
	local newposcheck = newposchecktable.name
	local walkable = minetest.registered_nodes[newposcheck].walkable
	
	if fields.dig then
		if walkable then
			dig_pos.z = dig_pos.z - dirz
			dig_pos.x = dig_pos.x - dirx
			move = false
			minetest.set_node(dig_pos, {name="air"})
			minetest.sound_play("moveokay", {to_player = player_name,gain = 1.0,})
		else
			minetest.sound_play("moveerror", {to_player = player_name,gain = 1.0,})
		end
	end
	
	if (not walkable) and move then 
		-- Move node to new position
		minetest.remove_node(pos)
		minetest.set_node(new_pos, node) --move node to new position
		minetest.get_meta(new_pos):from_table(meta) --set metadata of new node
		-- Update formspec reference position, wait for next instructions
		turtle_formspec_positions[player_name] = new_pos
		
		minetest.sound_play("moveokay", {to_player = player_name,gain = 1.0,})
	else
		minetest.sound_play("moveerror", {to_player = player_name,gain = 1.0,})
	end
end)