local F = advtrains.formspec
local D = advtrains.distant
local I = advtrains.interlocking

function advtrains.interlocking.show_distant_signal_form(pos, pname)
	local form = {"size[7,7]"}
	form[#form+1] = advtrains.interlocking.make_signal_formspec_tabheader(pname, pos, 7, 3)
	local main, set_by = D.get_main(pos)
	if main then
		local pts_main = minetest.pos_to_string(main)
		form[#form+1] = F.S_label(0.5, 0.5, "This signal is a distant signal of @1.", pts_main)
		if set_by == "manual" then
			form[#form+1] = F.S_label(0.5, 1, "The assignment is made manually.")
		elseif set_by == "routesetting" then
			form[#form+1] = F.S_label(0.5, 1, "The assignment is made by the routesetting system.")
		end
	else
		form[#form+1] = F.S_label(0.5, 0.5, "This signal is not assigned to a main signal.")
		form[#form+1] = F.S_label(0.5, 1, "The distant aspect of the signal is not used.")
	end
	if set_by ~= nil then
		form[#form+1] = F.S_button_exit(0.5, 1.5, 3, 1, "unassign_dst", "Unassign")
		form[#form+1] = F.S_button_exit(3.5, 1.5, 3, 1, "assign_dst", "Reassign")
	else
		form[#form+1] = F.S_button_exit(0.5, 1.5, 6, 1, "assign_dst", "Assign")
	end
	minetest.show_formspec(pname, "advtrains:distant_" .. minetest.pos_to_string(pos), table.concat(form))
end

local signal_pos = {}
local function init_signal_assignment(pname, pos)
	if not minetest.check_player_privs(pname, "interlocking") then
		minetest.chat_send_player(pname, attrans("This operation is not allowed without the @1 privilege.", "interlocking"))
		return
	end
	signal_pos[pname] = pos
	minetest.chat_send_player(pname, attrans("Please punch the signal to use as the main signal."))
end

minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
	local pname = player:get_player_name()
	if not minetest.check_player_privs(pname, "interlocking") then
		return
	end
	local spos = signal_pos[pname]
	if not spos then
		return
	end
	signal_pos[pname] = nil
	local is_signal = minetest.get_item_group(node.name, "advtrains_signal") >= 2
	if not is_signal then
		minetest.chat_send_player(pname, attrans("Incompatible signal."))
		return
	end
	minetest.chat_send_player(pname, attrans("Successfully assigned signal."))
	D.assign(pos, spos, "manual")
end)

minetest.register_on_player_receive_fields(function(player, formname, fields)
	local pname = player:get_player_name()
	local pos = minetest.string_to_pos(string.match(formname, "^advtrains:distant_(.+)$") or "")
	if not pos then
		return
	end
	if not minetest.check_player_privs(pname, "interlocking") then
		return
	end
	if advtrains.interlocking.handle_signal_formspec_tabheader_fields(pname, fields) then
		return true
	end
	if fields.unassign_dst then
		D.unassign_dst(pos)
	elseif fields.assign_dst then
		init_signal_assignment(pname, pos)
	end
end)