import type { DrawTextOption } from './base'

// const canvas = new OffscreenCanvas(0, 0);
const canvas = document.createElement('canvas')
const canvasCtx = canvas.getContext('2d')

export function blobToDataURL(data: Blob): Promise<string>
{
  return new Promise((resolve) =>
  {
    let reader = new FileReader()
    reader.onload = (response) =>
    {
      resolve(response.target.result as string)
    }
    reader.readAsDataURL(data)
  })
}

export function getStringWidth(
  text: string,
  width: number,
  height: number,
  option: DrawTextOption,
): number
{
  canvasCtx.clearRect(
    0,
    0,
    width,
    height,
  )
  canvasCtx.textAlign = option.textAlign as CanvasTextAlign
  canvasCtx.textBaseline = option.textBaseline as CanvasTextBaseline
  canvasCtx.fillStyle = option.fillStyle
  canvasCtx.font
        = `${option.fontWeight} ${option.fontSize}px ${option.fontFamily}`
  return canvasCtx.measureText(text).width
}