MapGIS Client for JavaScript API

import { Log, RendererType } from '../../index'
import { defined } from '../../util'

/**
 * @description: 更新要素的符号信息
 * @param {*} feature
 * @param {*} rendererSymbol
 * @param {Boolean} visible
 * @return {*}
 */
function updateFeatureSymbol(feature, rendererSymbol, visible) {
  if (!feature || !feature.symbol || !rendererSymbol) return
  const oldJSON = feature.symbol.toJSON()
  const newJSON = rendererSymbol.toJSON()
  if (oldJSON !== newJSON) {
    feature.symbol = newJSON
  }
  feature.visible = defined(visible) ? visible : true
}

/**
 * @description: 简单解析数值表达式
 * @param {*} feature
 * @param {String} expression
 * @return {*}
 */
function parseExpression(feature, expression) {
  if (!expression) return ''
  const excuteStr = expression.replace('$feature', `feature.attributes`)
  try {
    // eslint-disable-next-line no-eval
    const v = eval(excuteStr)
    return v
  } catch (err) {
    Log.info('字段表达式输入值非法')
  }
  return ''
}

/**
 * @description 渲染要素集
 * @public
 * @param {FeatureSet|Array<Feature>} featureSet
 * @param {*} renderer
 * @return {*}
 */
function applyRenderer(features, renderer) {
  renderer = renderer || {}
  switch (renderer.type) {
    case RendererType.simple: {
      const rendererSymbol = renderer.symbol
      features.forEach((feature) => {
        updateFeatureSymbol(feature, rendererSymbol)
      })
      break
    }
    case RendererType.uniqueValue: {
      const defaultSymbol = renderer.defaultSymbol || {}
      const defaultVisible = renderer.defaultVisible
      const uniqueValueInfos = renderer.uniqueValueInfos || []
      const valueExpression = renderer.valueExpression || ''
      for (let i = 0; i < features.length; i++) {
        const feature = features[i]
        const field = renderer.field || ''
        const attributes = feature.attributes || {}
        let value = attributes[field]
        value = defined(value)
          ? value
          : parseExpression(feature, valueExpression)
        if (defined(value)) {
          let uniqueSymbol = null
          let _uniqueValueInfo = null
          for (let j = 0; j < uniqueValueInfos.length; j++) {
            const uniqueValueInfo = uniqueValueInfos[j]
            if (uniqueValueInfo.value === value) {
              uniqueSymbol = uniqueValueInfo.symbol
              _uniqueValueInfo = uniqueValueInfo
              break
            }
          }
          if (uniqueSymbol) {
            updateFeatureSymbol(feature, uniqueSymbol, _uniqueValueInfo.visible)
            // eslint-disable-next-line no-continue
            continue
          }
        }
        // 采用默认的样式
        updateFeatureSymbol(feature, defaultSymbol, defaultVisible)
      }
      break
    }
    case RendererType.classBreak: {
      const defaultSymbol = renderer.defaultSymbol || {}
      const classBreakInfos = renderer.classBreakInfos || []
      const valueExpression = renderer.valueExpression || ''
      const defaultVisible = renderer.defaultVisible
      for (let i = 0; i < features.length; i++) {
        const feature = features[i]
        const field = renderer.field || ''
        const attributes = feature.attributes || {}
        let value = attributes[field]
        value = defined(value)
          ? value
          : parseExpression(feature, valueExpression)

        if (defined(value)) {
          let classBreakSymbol = null
          let _classBreakInfo = null
          for (let j = 0; j < classBreakInfos.length; j++) {
            const classBreakInfo = classBreakInfos[j]
            const maxValue = classBreakInfo.maxValue
            const minValue = classBreakInfo.minValue
            if (value >= minValue && value < maxValue) {
              classBreakSymbol = classBreakInfo.symbol
              _classBreakInfo = classBreakInfo
              break
            }
          }
          if (classBreakSymbol) {
            updateFeatureSymbol(
              feature,
              classBreakSymbol,
              _classBreakInfo.visible
            )
            // eslint-disable-next-line no-continue
            continue
          }
        }
        // 采用默认的样式
        updateFeatureSymbol(feature, defaultSymbol, defaultVisible)
      }

      break
    }
    default: {
      const rendererSymbol = renderer.symbol
      features.forEach((feature) => {
        updateFeatureSymbol(feature, rendererSymbol)
      })
      break
    }
  }
}

export { applyRenderer }