crossfilter/universe

'use strict'

var _ = require('./lodash')

module.exports = function(service) {
  return function clear(def) {
    // Clear a single or multiple column definitions
    if (def) {
      def = _.isArray(def) ? def : [def]
    }

    if (!def) {
      // Clear all of the column defenitions
      return Promise.all(
        _.map(service.columns, disposeColumn)
      ).then(function() {
        service.columns = []
        return service
      })
    }

    return Promise.all(
      _.map(def, function(d) {
        if (_.isObject(d)) {
          d = d.key
        }
        // Clear the column
        var column = _.remove(service.columns, function(c) {
          if (_.isArray(d)) {
            return !_.xor(c.key, d).length
          }
          if (c.key === d) {
            if (c.dynamicReference) {
              return false
            }
            return true
          }
        })[0]

        if (!column) {
          // console.info('Attempted to clear a column that is required for another query!', c)
          return
        }

        disposeColumn(column)
      })
    ).then(function() {
      return service
    })

    function disposeColumn(column) {
      var disposalActions = []
      // Dispose the dimension
      if (column.removeListeners) {
        disposalActions = _.map(column.removeListeners, function(listener) {
          return Promise.resolve(listener())
        })
      }
      var filterKey = column.key
      if (column.complex === 'array') {
        filterKey = JSON.stringify(column.key)
      }
      if (column.complex === 'function') {
        filterKey = column.key.toString()
      }
      delete service.filters[filterKey]
      if (column.dimension) {
        disposalActions.push(Promise.resolve(column.dimension.dispose()))
      }
      return Promise.all(disposalActions)
    }
  }
}