package main

import (
	"fmt"
	"math"

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

const HEIGHT = 600
const WIDTH = 800

func main() {
    fmt.Println("hello world")
    rl.SetConfigFlags(rl.FlagMsaa4xHint)
    rl.InitWindow(WIDTH, HEIGHT, "raylib [core] example - basic window")
    defer rl.CloseWindow()
    // rl.SetTargetFPS(60)

    rl.BeginDrawing()
    rl.ClearBackground(rl.RayWhite)
    rl.EndDrawing()

    var innerCircleRadius float32 = HEIGHT/2
    var outerCircleRadius float32 = innerCircleRadius/2
    trace := true

    for !rl.WindowShouldClose() {
        rl.BeginDrawing()
        if !trace {
            rl.ClearBackground(rl.RayWhite)
        }

        if rl.IsKeyPressed(rl.KeySpace) {
            trace = !trace
        }

        angle := float64(rl.GetTime() * 1)
        center := rl.NewVector2(WIDTH/2, HEIGHT/2)
        outerCircle := rl.NewVector2(float32(math.Cos(angle)), float32(math.Sin(angle)))
        outerCircle = rl.Vector2Scale(outerCircle, innerCircleRadius - outerCircleRadius)
        outerCircle = rl.Vector2Add(outerCircle, center)

        if !trace {
            // outer circle
            rl.DrawCircleV(outerCircle, outerCircleRadius, rl.Black)
            rl.DrawCircleV(outerCircle, outerCircleRadius-1, rl.RayWhite)
            rl.DrawLineV(outerCircle, center, rl.Black)
        }

        var tipSize float32 = 6
        if trace {
            tipSize = 2
        }
        // tip
        angle *= -7.3
        tip := rl.NewVector2(float32(math.Cos(angle)), float32(math.Sin(angle)))
        tip = rl.Vector2Scale(tip, outerCircleRadius)
        tip = rl.Vector2Add(tip, outerCircle)
        rl.DrawCircleV(tip, tipSize, rl.Blue)

        if !trace {
            // inner circle
            rl.DrawCircleLines(WIDTH/2, HEIGHT/2, innerCircleRadius, rl.Black)
        }

        rl.EndDrawing()
    }
}