package game

import (
	"math"
)

func IsPositionInRange(origin Position, pos Position, r int) bool {
	x, y := float64(pos.X-origin.X), float64(pos.Y-origin.Y)
	ax, ay := math.Abs(x), math.Abs(y)
	if ax > float64(r) || ay > float64(r) {
		return false
	}

	var abs float64
	if pos.X > pos.Y {
		abs = ax + math.Floor(ay/2)
	} else {
		abs = ay + math.Floor(ax/2)
	}

	return abs <= float64(r)
}

func PositionsInRange(origin Position, r int, includeOrigin bool) []Position {
	positions := []Position{}
	for x := -r; x <= r; x++ {
		for y := -r; y <= r; y++ {
			pos := Position{origin.X + x, origin.Y + y}
			if pos.X < 0 || pos.Y < 0 {
				continue
			}

			if !includeOrigin && pos == origin {
				continue
			}

			if IsPositionInRange(origin, pos, r) {
				positions = append(positions, pos)
			}
		}
	}
	return positions
}

func TilesInRangeFromOrigin(m *Map, origin Position, r int) []*Tile {
	tiles := []*Tile{}
	for _, pos := range PositionsInRange(origin, r, false) {
		tile := m.TileAt(pos)
		if tile != nil {
			tiles = append(tiles, tile)
		}
	}
	return tiles
}

func TilesInRange(m *Map, p Permanent, r int) []*Tile {
	return TilesInRangeFromOrigin(m, p.Tile().Position, r)
}