import proj4 from 'proj4'
import { register } from 'ol/proj/proj4'
import { ImageWMS } from 'ol/source'
import { Image as ImageLayer } from 'ol/layer'

// China Geodetic Coordinate System 2000
proj4.defs('EPSG:4490', '+proj=longlat +ellps=GRS80 +no_defs')
// 注册进 openlayer
register(proj4)

export default function wmsLayer(url, option) {
  const { zIndex, radio = 1.0, params, opacity } = option

  const source = new ImageWMS({
    ratio: radio,
    url: url,
    crossOrigin: 'anonymous',
    params: {},
    opacity
  })

  // 处理 layerDefs 为字符串
  source._updateParams = source.updateParams
  source.updateParams = function(params) {
    const newVar = Object.assign({}, params, {
      cql_filter: params.cql_filter
    })
    source._updateParams(newVar)
  }

  params && source.updateParams(params)

  return new ImageLayer({
    source: source,
    zIndex
  })
}