import * as React from 'react';

const noop = () => {};

type ID = string | number;
interface BatchSelectContextProps {
  selectedItems: [];
  itemsSelectedCount: number;
  isItemSelected: (id: ID) => boolean;
  isAllItemsSelected: boolean;
  isPartiallySelected: boolean;
  selectItem: (id: ID) => void;
  deselectItem: (id: ID) => void;
  selectAll: () => void;
  deselectAll: () => void;
  toggleItem: (id: ID) => void;
  toggleAllItems: () => void;
}
export const BatchSelectContext = React.createContext<BatchSelectContextProps>({
  selectedItems: null,
  itemsSelectedCount: null,
  isItemSelected: () => false,
  isAllItemsSelected: null,
  isPartiallySelected: null,
  selectItem: noop,
  deselectItem: noop,
  selectAll: noop,
  deselectAll: noop,
  toggleItem: noop,
  toggleAllItems: noop,
});

interface ReducerState {
  idKey: ID;
  selectedItems: (string | number)[];
}
interface ReducerAction {
  type: 'select' | 'deselect' | 'selectAll' | 'deselectAll';
  payload?: any;
}
function reducer(state: ReducerState, action: ReducerAction) {
  switch (action.type) {
    case 'select':
      return {
        ...state,
        selectedItems: [...state.selectedItems, action.payload],
      };
    case 'deselect':
      return {
        ...state,
        selectedItems: state.selectedItems.filter(item => item !== action.payload),
      };
    case 'selectAll':
      return {
        ...state,
        selectedItems: action.payload.map((d: any) => d[state.idKey]),
      };
    case 'deselectAll':
      return {
        ...state,
        selectedItems: [],
      };
    default:
      return state;
  }
}

export function useBatchSelect(
  data: any,
  { idKey = 'id', initialSelectedItems = [] }: { idKey?: ID; initialSelectedItems?: (ID)[] } = {},
) {
  const [state, dispatch] = React.useReducer(reducer, {
    selectedItems: initialSelectedItems,
    idKey,
  });

  const selectedItems = state.selectedItems;
  const itemsSelectedCount = state.selectedItems.length;
  const isItemSelected = React.useCallback(id => state.selectedItems.indexOf(id) >= 0, [
    state.selectedItems,
  ]);
  const isAllItemsSelected = data.length === state.selectedItems.length;
  const isPartiallySelected = selectedItems.length > 0 && !isAllItemsSelected;
  const selectItem = (id: ID) => dispatch({ type: 'select', payload: id });
  const deselectItem = (id: ID) => dispatch({ type: 'deselect', payload: id });
  const selectAll = () => dispatch({ type: 'selectAll', payload: data });
  const deselectAll = () => dispatch({ type: 'deselectAll' });
  const toggleItem = (id: ID) => {
    const type = isItemSelected(id) ? 'deselect' : 'select';
    dispatch({ type, payload: id });
  };

  const toggleAllItems = () => {
    if (itemsSelectedCount) {
      deselectAll();
    } else {
      selectAll();
    }
  };

  return {
    selectedItems,
    isItemSelected,
    isAllItemsSelected,
    itemsSelectedCount,
    isPartiallySelected,
    selectItem,
    deselectItem,
    selectAll,
    deselectAll,
    toggleItem,
    toggleAllItems,
  };
}