local expectlib = require("cc.expect")
local expect, field = expectlib.expect, expectlib.field
local term_stack = {}

local cursor_stack = { }
local setCursorPos = term.setCursorPos
local getCursorPos = term.getCursorPos
local cursor_ox = 0
local cursor_oy = 0
function term_stack.push_cursor(x, y)
	expect(1, x, "number", "nil")
	expect(2, y, "number", "nil")

	local dx = ((x or 1) - 1)
	local dy = ((y or 1) - 1)

	table.insert(cursor_stack, { dx, dy })
	cursor_ox = cursor_ox + dx
	cursor_oy = cursor_oy + dy
	setCursorPos(cursor_ox+1, cursor_oy+1)
end

function term_stack.pop_cursor()
	local frame = table.remove(cursor_stack)
	cursor_ox = cursor_ox - frame[1]
	cursor_oy = cursor_oy - frame[2]
	setCursorPos(cursor_ox+1, cursor_oy+1)
end

function term.setCursorPos(x, y)
	expect(1, x, "number")
	expect(2, y, "number")

	setCursorPos(x + cursor_ox, y + cursor_oy)
end

function term.getCursorPos()
	local x, y = getCursorPos()
	return x - cursor_ox, y - cursor_oy
end



local size_stack = {}
local getSize = term.getSize
local current_w, current_h = getSize()
function term_stack.push_size(w, h)
	expect(1, w, "number")
	expect(2, h, "number")

	table.insert(size_stack, { current_w, current_h })
	current_w = w
	current_h = h
	return w, h
end

function term_stack.pop_size()
	local frame = table.remove(cursor_stack)
	current_w = frame[1]
	current_h = frame[2]
end

function term.getSize()
	return current_w, current_h
end



function term_stack.push_rect(x, y, w, h)
	if type(x) == "table" then
		local rect = x
		field(rect, "x", "number")
		field(rect, "y", "number")
		field(rect, "w", "number")
		field(rect, "h", "number")

		term_stack.push_cursor(rect.x, rect.y)
		term_stack.push_size(rect.w, rect.h)
		return rect.w, rect.h
	else
		expect(1, x, "number")
		expect(2, y, "number")
		expect(3, w, "number")
		expect(4, h, "number")

		term_stack.push_cursor(x, y)
		term_stack.push_size(w, h)
		return w, h
	end
end

function term_stack.pop_rect()
	term_stack.pop_cursor()
	term_stack.pop_size()
end

return term_stack