import union from 'lodash/union'
import { handleActions } from 'redux-actions'
import { initialState } from 'mocks/state/initialState'
import { set } from 'dot-prop-immutable'

// creates a reducer managing pagination
const paginationReducer = ({ types }) => {
  if (!Array.isArray(types) || types.length !== 4) {
    throw new Error('Expected types to be an array of four elements.')
  }
  if (!types.every(t => typeof t === 'string')) {
    throw new Error('Expected types to be strings.')
  }

  const [requestType, successType, failureType, clearSearchType] = types

  const updatePagination = handleActions({
    [`${requestType}`]: (state, action) => {
      state = set(state, 'fetching', true)

      return state
    },
    [`${successType}`]: (state, action) => {
      const { result } = action.payload.response
      const ids = union(state.ids, Array.isArray(result) ? result : [result])

      state = set(state, 'fetching', false)
      state = set(state, 'ids', ids)

      return state
    },
    [`${failureType}`]: (state, action) => {
      state = set(state, 'fetching', false)
      return state
    }
  }, {
    fetching: false,
    ids: []
  })

  return handleActions({
    [`${requestType}`]: (state, action) => {
      const { limit, skip, term } = action.meta.params

      if (term) {
        state = set(state, 'search', { term })
        state = set(state, 'search', updatePagination(state.search, action))
      } else {
        state = set(state, 'limit', limit)
        state = set(state, 'skip', skip)
        state = set(state, `pages.${(skip / limit) + 1}`, updatePagination(state.pages[(skip / limit) + 1], action))
      }

      return state
    },
    [`${successType}`]: (state, action) => {
      const { limit, skip, search } = state
      state = search.fetching
        ? set(state, 'search', updatePagination(state.search, action))
        : set(state, `pages.${(skip / limit) + 1}`, updatePagination(state.pages[(skip / limit) + 1], action))

      return state
    },
    [`${failureType}`]: (state, action) => {
      const { limit, skip, search } = state

      state = search.fetching
        ? set(state, 'search', updatePagination(state.search, action))
        : set(state, `pages.${(skip / limit) + 1}`, updatePagination(state.pages[(skip / limit) + 1], action))

      return state
    },
    [`${clearSearchType}`]: (state, action) => {
      state = set(state, 'search', { fetching: false, ids: [] })
      return state
    }
  }, initialState)
}

export default paginationReducer