import {
  browser, requestAudioContext,
  randint, randrange, clamp,
} from './lib/util'

import mouse from './lib/mouse'
import color from './lib/color'

const canvas = document.createElement('canvas')
const ctx = canvas.getContext('2d')
document.body.appendChild(canvas)

let w, h
function resize(){
  w = canvas.width = window.innerWidth
  h = canvas.height = window.innerHeight
}
document.body.addEventListener('resize', resize)
resize()

function clear(n){
  ctx.fillStyle = 'rgba(255,255,255,' + (n || 0.5) + ')'
  ctx.fillRect(0,0,w,h)
}
function triangle(px, py, r) {
  ctx.save()
  ctx.globalCompositeOperation = 'difference'
  ctx.fillStyle = color((px+py)/(w+h), 0, 1, 1)
  function p(){
    let theta = randrange(0, Math.PI*2)
    let x = px + Math.cos(theta) * r
    let y = py + Math.sin(theta) * r
    return { x, y }
  }
  ctx.beginPath()
  const p0 = p(), p1 = p(), p2 = p()
  ctx.moveTo(p0.x, p0.y)
  ctx.lineTo(p1.x, p1.y)
  ctx.lineTo(p2.x, p2.y)
  ctx.lineTo(p0.x, p0.y)
  ctx.fill()
  ctx.restore()
}

export default {
  triangle, clear
}