import { RecipeCollectionFilterItem } from './smart-collection-model';
import { Enum, isEnumType } from '../../library/enum';
import { DocumentQuery } from 'mongoose';
import { Recipe } from '../recipe';

export const RecipeFilterAttribute = Enum('TAG', 'INGREDIENT');
export type RecipeFilterAttribute = Enum<typeof RecipeFilterAttribute>;

export const RecipeFilterAction = Enum(
  'EQUAL',
  'NOT_EQUAL',
  'INCLUDE',
  'NOT_INCLUDE'
);
export type RecipeFilterAction = Enum<typeof RecipeFilterAction>;

type RecipeFilterOptions = {
  [key in RecipeFilterAttribute]: {
    label: string;
    availableActions: RecipeFilterAction[];
  };
};

export const recipeFilters: RecipeFilterOptions = {
  [RecipeFilterAttribute.TAG]: {
    label: 'Tags',
    availableActions: [RecipeFilterAction.EQUAL, RecipeFilterAction.INCLUDE],
  },
  [RecipeFilterAttribute.INGREDIENT]: {
    label: 'Ingredients',
    availableActions: [RecipeFilterAction.INCLUDE],
  },
};

export function validateFilterItem(filter: RecipeCollectionFilterItem) {
  if (!isEnumType(RecipeFilterAttribute, filter.attribute)) {
    throw new Error(`${filter.attribute} is not a valide attribute type`);
  }

  if (
    recipeFilters[filter.attribute].availableActions.indexOf(filter.action) < 0
  ) {
    const availActions = recipeFilters[filter.attribute].availableActions.join(
      ' '
    );
    throw new Error(
      `${filter.action} is not a valid action for ${filter.attribute}. Must be one of ${availActions}`
    );
  }

  return true;
}

export function buildFilterQuery(
  filters: RecipeCollectionFilterItem[],
  query: DocumentQuery<Recipe[], Recipe>
) {
  let filterQuery = query;

  filters.forEach(filter => {
    validateFilterItem(filter);

    switch (filter.attribute) {
      case RecipeFilterAttribute.TAG:
        filterQuery = filterByTag(filter, filterQuery);
    }
  });
  return filterQuery;
}

//
// Attribute Functions
//

function filterByTag(
  filter: RecipeCollectionFilterItem,
  query: DocumentQuery<Recipe[], Recipe>
) {
  switch (filter.action) {
    case RecipeFilterAction.INCLUDE:
      return query.where({
        tags: { $all: filter.value.split(',') },
      });
    default:
      return query;
  }
}