package entity

import (
	rl "github.com/gen2brain/raylib-go/raylib"
)

type EntityAnimation interface {
	Draw(step int, windowPosition rl.Vector2, color rl.Color) error
	GetSpeed() int
}

type AnimationTracker interface {
	Draw(windowPosition rl.Vector2, color rl.Color) error
	SetAnimation(id int)
}

const (
	// These line up with the VEC_DIRECTIONS slice

	DirLeft int = iota
	DirRight
	DirUp
	DirDown
)

// The following are axis direction vectors based on world coordinates.
// UP/DOWN is intentionally UP = positive (which is different from window coordinates)
var (
	VecLeft  = rl.Vector2{X: -1, Y: 0}
	VecRight = rl.Vector2{X: 1, Y: 0}
	VecUp    = rl.Vector2{X: 0, Y: 1}
	VecDown  = rl.Vector2{X: 0, Y: -1}

	VecDirections = []rl.Vector2{
		// Prefer left/right animations by checking them first in the list
		VecLeft,
		VecRight,
		VecUp,
		VecDown,
	}
)

func determineClosestDirection(velocity rl.Vector2) int {
	closest := DirRight
	max := float32(0)
	buffer := float32(0.5) // This buffer lets us stick to the left/right animations for diagonal movement

	for i, dir := range VecDirections {
		dot := rl.Vector2DotProduct(velocity, dir)
		if dot > max+buffer {
			max = dot
			closest = i
		}
	}

	return closest
}