crossfilter/universe

'use strict'

var _ = require('./lodash')

var aggregation = require('./aggregation')

module.exports = function (/* service */) {
  return {
    post: post,
    sortByKey: sortByKey,
    limit: limit,
    squash: squash,
    change: change,
    changeMap: changeMap,
  }

  function post(query, parent, cb) {
    query.data = cloneIfLocked(parent)
    return Promise.resolve(cb(query, parent))
  }

  function sortByKey(query, parent, desc) {
    query.data = cloneIfLocked(parent)
    query.data = _.sortBy(query.data, function (d) {
      return d.key
    })
    if (desc) {
      query.data.reverse()
    }
  }

  // Limit results to n, or from start to end
  function limit(query, parent, start, end) {
    query.data = cloneIfLocked(parent)
    if (_.isUndefined(end)) {
      end = start || 0
      start = 0
    } else {
      start = start || 0
      end = end || query.data.length
    }
    query.data = query.data.splice(start, end - start)
  }

  // Squash results to n, or from start to end
  function squash(query, parent, start, end, aggObj, label) {
    query.data = cloneIfLocked(parent)
    start = start || 0
    end = end || query.data.length
    var toSquash = query.data.splice(start, end - start)
    var squashed = {
      key: label || 'Other',
      value: {},
    }
    _.recurseObject(aggObj, function (val, key, path) {
      var items = []
      _.forEach(toSquash, function (record) {
        items.push(_.get(record.value, path))
      })
      _.set(squashed.value, path, aggregation.aggregators[val](items))
    })
    query.data.splice(start, 0, squashed)
  }

  function change(query, parent, start, end, aggObj) {
    query.data = cloneIfLocked(parent)
    start = start || 0
    end = end || query.data.length
    var obj = {
      key: [query.data[start].key, query.data[end].key],
      value: {},
    }
    _.recurseObject(aggObj, function (val, key, path) {
      var changePath = _.clone(path)
      changePath.pop()
      changePath.push(key + 'Change')
      _.set(obj.value, changePath, _.get(query.data[end].value, path) - _.get(query.data[start].value, path))
    })
    query.data = obj
  }

  function changeMap(query, parent, aggObj, defaultNull) {
    defaultNull = _.isUndefined(defaultNull) ? 0 : defaultNull
    query.data = cloneIfLocked(parent)
    _.recurseObject(aggObj, function (val, key, path) {
      var changePath = _.clone(path)
      var fromStartPath = _.clone(path)
      var fromEndPath = _.clone(path)

      changePath.pop()
      fromStartPath.pop()
      fromEndPath.pop()

      changePath.push(key + 'Change')
      fromStartPath.push(key + 'ChangeFromStart')
      fromEndPath.push(key + 'ChangeFromEnd')

      var start = _.get(query.data[0].value, path, defaultNull)
      var end = _.get(query.data[query.data.length - 1].value, path, defaultNull)

      _.forEach(query.data, function (record, i) {
        var previous = query.data[i - 1] || query.data[0]
        _.set(query.data[i].value, changePath, _.get(record.value, path, defaultNull) - (previous ? _.get(previous.value, path, defaultNull) : defaultNull))
        _.set(query.data[i].value, fromStartPath, _.get(record.value, path, defaultNull) - start)
        _.set(query.data[i].value, fromEndPath, _.get(record.value, path, defaultNull) - end)
      })
    })
  }
}

function cloneIfLocked(parent) {
  return parent.locked ? _.clone(parent.data) : parent.data
}