package clockface

import (
	"math"
	"time"
)

// Point represents a two-dimentional Cartesian coordinate
type Point struct {
	X float64
	Y float64
}

// SecondHand is the unit vector of the second hand of an analogue clock at the time `t` represented as a Point
func SecondHand(t time.Time) Point {
	p := secondHandPoint(t)
	p = Point{p.X * 90, p.Y * 90}   // scale
	p = Point{p.X, -p.Y}            // flip
	p = Point{p.X + 150, p.Y + 150} // translate
	return p
}

func secondsInRadians(t time.Time) float64 {
	// XXX:Wanted 3.141592653589793 radians, but got 3.1415926535897936
	// return float64(t.Second()) * (math.Pi / 30)

	return math.Pi / (30 / float64(t.Second()))
}

func secondHandPoint(t time.Time) Point {
	angle := secondsInRadians(t)
	x := math.Sin(angle)
	y := math.Cos(angle)

	// XXX: Wanted {0 -1} Point, but got {1.2246467991473515e-16 -1}
	return Point{x, y}
}