/**
 * weapp-qrcode
 * 基于QRCode.js的小程序二维码生成工具
 */

import qrcode from 'qrcode-generator'

function drawCanvas (options) {
  options = options || {}
  options = {
    width: options.width || 200,
    height: options.height || 200,
    canvasId: options.canvasId || 'qrcode',
    text: options.text || '',
    margin: options.margin || 0,
    foreground: options.foreground || '#000000',
    background: options.background || '#ffffff',
    context: options.context
  }

  if (!options.context) {
    console.error('请传入context对象')
    return
  }

  // 计算二维码大小
  const typeNumber = 0 // 自动计算
  const errorCorrectionLevel = 'H'
  const qr = qrcode(typeNumber, errorCorrectionLevel)
  qr.addData(options.text)
  qr.make()

  const count = qr.getModuleCount()
  const ctx = options.context
  const tileW = options.width / count
  const tileH = options.height / count

  // 清空画布
  ctx.fillStyle = options.background
  ctx.fillRect(0, 0, options.width, options.height)

  // 绘制二维码
  for (let row = 0; row < count; row++) {
    for (let col = 0; col < count; col++) {
      ctx.fillStyle = qr.isDark(row, col) ? options.foreground : options.background
      const w = Math.ceil((col + 1) * tileW) - Math.floor(col * tileW)
      const h = Math.ceil((row + 1) * tileH) - Math.floor(row * tileH)
      ctx.fillRect(Math.round(col * tileW), Math.round(row * tileH), w, h)
    }
  }
}

export default drawCanvas