import { reducerWithInitialState } from 'typescript-fsa-reducers'
import { combineReducers } from 'redux'
import { sortBy } from 'lodash'

import * as actions from './actions'
import * as AuthActions from '../auth/actions'

const MAX_ACTIVITIES = 200

const loading = reducerWithInitialState(null)
  .cases([
    actions.fetchActivitiesSuccess,
    actions.fetchActivitiesByEmailSuccess,
  ], () => false)
  .cases([
    actions.fetchActivities,
    actions.fetchActivitiesPending,
    actions.fetchActivitiesByEmail,
  ], () => true)

const loaded = reducerWithInitialState(false)
  .case(actions.fetchActivitiesSuccess, () => true)
  .case(AuthActions.logout, () => false)

const activities = reducerWithInitialState([])
  .cases([
    actions.fetchActivitiesSuccess,
    actions.receiveActivities,
  ], (state, activities) => {
    const filtered = state.filter((activity) => {
      return !activities.find(a => a.id === activity.id)
    })
    const combined = sortBy(filtered.concat(activities), 'at')
    if (combined.length > MAX_ACTIVITIES) {
      return combined.slice(combined.length - MAX_ACTIVITIES)
    } else {
      return combined
    }
  })
  .case(AuthActions.logout, () => [])

const activitiesByEmail = reducerWithInitialState([])
  .case(actions.fetchActivitiesByEmailSuccess, (state, activities) => sortBy(activities, 'at'))
  .case(actions.receiveActivitiesByEmail, (state, activities) => {
    const filtered = state.filter((activity) => {
      return !activities.find(a => a.id === activity.id)
    })
    const combined = sortBy(filtered.concat(activities), 'at')
    if (combined.length > MAX_ACTIVITIES) {
      return combined.slice(combined.length - MAX_ACTIVITIES)
    } else {
      return combined
    }
  })
  .case(AuthActions.logout, () => [])

export default combineReducers({
  loading,
  loaded,
  activities,
  activitiesByEmail,
})