package game

import (
	"fmt"
)

// Position represents a zero-based position on the map.
// TODO: Change to a 1-based coordinate system.
//
//	This allows to use the zero value as invalid Position.
//
// The origin is the upper left corner of the map.
type Position struct {
	X int
	Y int
}

const POSITION_FMT = "(%d, %d)"

func (p Position) String() string {
	if p == INVALID_POSITION() {
		return "INVALID_POSITION"
	}

	return fmt.Sprintf(POSITION_FMT, p.X, p.Y)
}

func INVALID_POSITION() Position {
	return Position{-1, -1}
}

// Valid reports if a coordinate is smaller than 0.
func (p Position) Valid() bool {
	return p.X >= 0 && p.Y >= 0
}