package unit

import (
	"math"
	"strconv"
)

// Vec2 is a 2D vector of values with the unit of T.
type Vec2[T UnitConstraint] struct {
	X T `json:"x"`
	Y T `json:"y"`
}

// NewVec2FromVec2 takes an arbitrary Vec2 and returns it as a new vector with the type T.
func NewVec2FromVec2[I, T UnitConstraint](a Vec2[I]) Vec2[T] {
	return Vec2[T]{T(a.X), T(a.Y)}
}

func (a Vec2[T]) String() string {
	return "(" +
		strconv.FormatFloat(float64(a.X), 'f', -1, 64) + ", " +
		strconv.FormatFloat(float64(a.Y), 'f', -1, 64) +
		")\u00A0" + T.UnitSymbol(0)
}

func (a Vec2[T]) EqualWithPrecision(b Vec2[T], precision T) bool {
	if math.Abs(float64(a.X-b.X)) > float64(precision) {
		return false
	}
	if math.Abs(float64(a.Y-b.Y)) > float64(precision) {
		return false
	}
	return true
}

func (a Vec2[T]) Unitless() Vec2[Unitless] {
	return Vec2[Unitless]{Unitless(a.X), Unitless(a.Y)}
}

func (a Vec2[T]) Added(b Vec2[T]) Vec2[T] {
	return Vec2[T]{a.X + b.X, a.Y + b.Y}
}

func (a Vec2[T]) Subed(b Vec2[T]) Vec2[T] {
	return Vec2[T]{a.X - b.X, a.Y - b.Y}
}

func (a Vec2[T]) Scaled(s float64) Vec2[T] {
	return Vec2[T]{a.X * T(s), a.Y * T(s)}
}

func (a Vec2[T]) Normalized() Vec2[Unitless] {
	return a.Scaled(1 / float64(a.Length())).Unitless()
}

func (a Vec2[T]) LengthSqr() T {
	return a.X*a.X + a.Y*a.Y
}

func (a Vec2[T]) Length() T {
	return T(math.Abs(float64(a.LengthSqr())))
}