// paintui handles turning sdl input things
// into drawing instructions
// it might have some kind of state machine
// for doing smooth lines between discrete mouse positions

// all mouse pos stuff in this module is in world coordinates
// someone else is responsible for doing the transform from
// screen to world coords.

use drawing;
use drawing::{pos};

export type state = struct {
	// last known mouse position, in world coordinates
	last_mouse_pos: pos,
	// last known mouse pressed-ness
	last_mouse_pressed: bool

};

export fn tick(
	pstate: *state,
	mouse_pos: pos, mouse_pressed: bool
) (void | drawing::op) = {
	defer {
		pstate.last_mouse_pos = mouse_pos;
		pstate.last_mouse_pressed = mouse_pressed;
	};

	// if mouse down and (position moved OR newly pressed)
	return if (mouse_pressed
		&& (mouse_pos.0 != pstate.last_mouse_pos.0
			|| mouse_pos.1 != pstate.last_mouse_pos.1
			|| (!pstate.last_mouse_pressed)))
		mouse_pos: drawing::op_circle
	else void;
};