package main

import (
	"image/color"
	"log"
	"math"
	"math/rand"

	"gonum.org/v1/plot"
	"gonum.org/v1/plot/plotter"
	"gonum.org/v1/plot/vg"
	"gonum.org/v1/plot/vg/draw"
)

func main() {
	rand.Seed(103)
	randsinpts := func(n int, maxt float64) plotter.XYs {
		pts := make(plotter.XYs, n)
		for idx := range pts {
			t := rand.Float64() * maxt
			pts[idx].X = t
			pts[idx].Y = math.Sin(t)
		}
		return pts
	}

	sinn := func(n int) plotter.XYs {
		pts := make(plotter.XYs, n)
		for idx := range pts {
			t := float64(idx) * 0.001
			pts[idx].X = t
			pts[idx].Y = math.Sin(t)
		}
		return pts
	}

	n := 10000
	data := sinn(n)

	p, err := plot.New()
	if err != nil {
		log.Panic(err)
	}
	p.Title.Text = "Sine stuff"

	p.X.Label.Text = "time (s)"
	p.X.Max = 10
	p.X.Min = 0

	p.Y.Label.Text = "w/e"
	p.Y.Max = 1
	p.Y.Min = -1

	p.Add(plotter.NewGrid())

	line, err := plotter.NewLine(data)
	if err != nil {
		log.Panic(err)
	}
	line.Color = color.RGBA{B: 255, A: 255}
	line.Width = vg.Millimeter / 2

	randpts := randsinpts(3, data[len(data)-1].X)
	points, err := plotter.NewScatter(randpts)
	if err != nil {
		log.Panic(err)
	}
	points.Shape = draw.CircleGlyph{}
	points.Color = color.RGBA{R: 255, A: 255}

	p.Add(line, points)

	err = p.Save(10*vg.Centimeter, 5*vg.Centimeter, "plot.png")
	if err != nil {
		log.Panic(err)
	}
}