import React from 'react'

import { actions, reducerHandlers } from '../hooks/useTable'
import { functionalUpdate } from '../utils'

const pluginName = 'useColumnOrder'

// Actions
actions.resetColumnOrder = 'resetColumnOrder'
actions.setColumnOrder = 'setColumnOrder'

// Reducer
reducerHandlers[pluginName] = (state, action) => {
  if (action.type === actions.init) {
    return {
      columnOrder: [],
      ...state,
    }
  }

  if (action.type === actions.resetColumnOrder) {
    return {
      ...state,
      columnOrder: [],
    }
  }

  if (action.type === actions.setColumnOrder) {
    return {
      ...state,
      columnOrder: functionalUpdate(action.columnOrder, state.columnOrder),
    }
  }
}

export const useColumnOrder = hooks => {
  hooks.columnsBeforeHeaderGroupsDeps.push((deps, instance) => {
    return [...deps, instance.state.columnOrder]
  })
  hooks.columnsBeforeHeaderGroups.push(columnsBeforeHeaderGroups)
  hooks.useMain.push(useMain)
}

useColumnOrder.pluginName = pluginName

function columnsBeforeHeaderGroups(columns, instance) {
  const {
    state: { columnOrder },
  } = instance

  // If there is no order, return the normal columns
  if (!columnOrder || !columnOrder.length) {
    return columns
  }

  const columnOrderCopy = [...columnOrder]

  // If there is an order, make a copy of the columns
  const columnsCopy = [...columns]

  // And make a new ordered array of the columns
  const columnsInOrder = []

  // Loop over the columns and place them in order into the new array
  while (columnsCopy.length && columnOrderCopy.length) {
    const targetColumnId = columnOrderCopy.shift()
    const foundIndex = columnsCopy.findIndex(d => d.id === targetColumnId)
    if (foundIndex > -1) {
      columnsInOrder.push(columnsCopy.splice(foundIndex, 1)[0])
    }
  }

  // If there are any columns left, add them to the end
  return [...columnsInOrder, ...columnsCopy]
}

function useMain(instance) {
  const { dispatch } = instance

  const setColumnOrder = React.useCallback(
    columnOrder => {
      return dispatch({ type: actions.setColumnOrder, columnOrder })
    },
    [dispatch]
  )

  return {
    ...instance,
    setColumnOrder,
  }
}