import { ProductCategory } from '../models/product-category';
import {
  initialFilters, Product,
  ProductIndexFilter,
  ProductIndexFilterIds, ProductIndexFilterUrl, ProductResourcesFetching,
  stockMovementInReasons,
  stockMovementOutReasons,
  StockMovementReason
} from '../models/product';
import { Machine } from '../models/machine';
import { StateParams } from '@uirouter/angularjs';
import ParsingLib from './parsing';
import ProductCategoryAPI from '../api/product-category';
import MachineAPI from '../api/machine';
import { Updater } from 'use-immer';

export default class ProductLib {
  /**
   * Map product categories by position
   * @param categories unsorted categories, as returned by the API
   */
  static sortCategories = (categories: Array<ProductCategory>): Array<ProductCategory> => {
    const sortedCategories = categories
      .filter(c => !c.parent_id)
      .sort((a, b) => a.position - b.position);
    const childrenCategories = categories
      .filter(c => typeof c.parent_id === 'number')
      .sort((a, b) => b.position - a.position);
    childrenCategories.forEach(c => {
      const parentIndex = sortedCategories.findIndex(i => i.id === c.parent_id);
      sortedCategories.splice(parentIndex + 1, 0, c);
    });
    return sortedCategories;
  };

  /**
   * Return the translation key associated with the given reason
   */
  static stockMovementReasonTrKey = (reason: StockMovementReason): string => {
    return `app.admin.store.stock_movement_reason.${reason}`;
  };

  static stockStatusTrKey = (product: Product): string => {
    if (product.stock.external < (product.quantity_min || 1)) {
      return 'app.public.stock_status.out_of_stock';
    }
    if (product.low_stock_threshold && product.stock.external <= product.low_stock_threshold) {
      return 'app.public.stock_status.limited_stock';
    }
    return 'app.public.stock_status.available';
  };

  /**
   * Check if the given stock movement is of type 'in' or 'out'
   */
  static stockMovementType = (reason: StockMovementReason): 'in' | 'out' => {
    if ((stockMovementInReasons as readonly StockMovementReason[]).includes(reason)) return 'in';
    if ((stockMovementOutReasons as readonly StockMovementReason[]).includes(reason)) return 'out';

    throw new Error(`Unexpected stock movement reason: ${reason}`);
  };

  /**
   * Return the given quantity, prefixed by its addition operator (- or +), if needed
   */
  static absoluteStockMovement = (quantity: number, reason: StockMovementReason): string => {
    if (ProductLib.stockMovementType(reason) === 'in') {
      return `+${quantity}`;
    } else {
      if (quantity < 0) return quantity.toString();
      return `-${quantity}`;
    }
  };

  /**
   * Add or remove the given category from the given list;
   * This may cause parent/children categories to be selected or unselected accordingly.
   */
  static categoriesSelectionTree = (allCategories: Array<ProductCategory>, currentSelection: Array<ProductCategory>, category: ProductCategory, operation: 'add'|'remove'): Array<ProductCategory> => {
    let list = [...currentSelection];
    const children = allCategories
      .filter(el => el.parent_id === category.id);

    if (operation === 'add') {
      list.push(category);
      if (children.length) {
        // if a parent category is selected, we automatically select all its children
        list = [...Array.from(new Set([...list, ...children]))];
      }
    } else {
      list.splice(list.indexOf(category), 1);
      const parent = allCategories.find(p => p.id === category.parent_id);
      if (category.parent_id && list.includes(parent)) {
        // if a child category is unselected, we unselect its parent
        list.splice(list.indexOf(parent), 1);
      }
      if (children.length) {
        // if a parent category is unselected, we unselect all its children
        children.forEach(child => {
          list.splice(list.indexOf(child), 1);
        });
      }
    }
    return list;
  };

  /**
   * Extract the IDS from the filters to pass them to the API
   */
  static indexFiltersToIds = (filters: ProductIndexFilter): ProductIndexFilterIds => {
    return {
      ...filters,
      categories: filters.categories?.map(c => c.id),
      machines: filters.machines?.map(m => m.id)
    };
  };

  /**
   * Prepare the filtering data from the filters to pass them to the router URL
   */
  static indexFiltersToRouterParams = (filters: ProductIndexFilter): ProductIndexFilterUrl => {
    let categoryTypeUrl = null;
    let category = null;
    if (filters.categories.length > 0) {
      categoryTypeUrl = filters.categories[0].parent_id === null ? 'c' : 'sc';
      category = filters.categories.map(c => c.slug)[0];
    }
    return {
      ...filters,
      machines: filters.machines?.map(m => m.slug),
      categories: filters.categories?.map(c => c.slug),
      category,
      categoryTypeUrl
    };
  };

  /**
   * Parse the provided URL and return a ready-to-use filter object
   */
  static readFiltersFromUrl = (params: StateParams, machines: Array<Machine>, categories: Array<ProductCategory>, defaultFilters = initialFilters): ProductIndexFilter => {
    const res: ProductIndexFilter = { ...defaultFilters };
    for (const key in params) {
      if (['#', 'categoryTypeUrl'].includes(key) || !Object.prototype.hasOwnProperty.call(params, key)) continue;

      const value = ParsingLib.parse(params[key]) || defaultFilters[key];
      switch (key) {
        case 'category': {
          const category = categories?.find(c => c.slug === value);
          const subCategories = category ? categories?.filter(c => c.parent_id === category.id) : [];
          res.categories = category ? [category, ...subCategories] : [];
          break;
        }
        case 'categories':
          res.categories = [...categories?.filter(c => (value as Array<string>)?.includes(c.slug))];
          break;
        case 'machines':
          res.machines = machines?.filter(m => (value as Array<string>)?.includes(m.slug));
          break;
        default:
          res[key] = value;
      }
    }
    return res;
  };

  /**
   * Fetch the initial ressources needed to initialise the store and its filters (categories and machines)
   */
  static fetchInitialResources = (setResources: Updater<ProductResourcesFetching>, onError: (message: string) => void, onProductCategoryFetched?: (data: Array<ProductCategory>) => void) => {
    ProductCategoryAPI.index().then(data => {
      setResources(draft => {
        return { ...draft, categories: { data: ProductLib.sortCategories(data), ready: true } };
      });
      if (typeof onProductCategoryFetched === 'function') onProductCategoryFetched(ProductLib.sortCategories(data));
    }).catch(error => {
      onError(error);
    });
    MachineAPI.index({ disabled: false }).then(data => {
      setResources(draft => {
        return { ...draft, machines: { data, ready: true } };
      });
    }).catch(onError);
  };

  /**
   * Update the given filter in memory with the new provided value
   */
  static updateFilter = (setResources: Updater<ProductResourcesFetching>, key: keyof ProductIndexFilter, value: unknown): void => {
    setResources(draft => {
      return {
        ...draft,
        filters: {
          ...draft.filters,
          data: {
            ...draft.filters.data,
            [key]: value
          }
        }
      };
    });
  };
}