import { Injectable } from '@angular/core';
import { orderBy } from 'lodash';
import { BehaviorSubject } from 'rxjs';
import { SortingOption } from './models/sorting-option.model';
import { SortingOrder, SortingOrders } from './models/sorting-order.type';
import { KeysOf } from '../utils';
import { IListable } from '../listing';
import { distinctUntilChanged, shareReplay } from 'rxjs/operators';

@Injectable()
export class SortingService<T extends IListable> {
    private readonly _sortingOption$ = new BehaviorSubject<SortingOption<T>>({
        column: 'searchKey',
        order: SortingOrders.asc,
    });
    readonly sortingOption$ = this._sortingOption$.asObservable().pipe(distinctUntilChanged(), shareReplay());

    get sortingOption(): SortingOption<T> | undefined {
        return this._sortingOption$.getValue();
    }

    static sort<T>(values: T[], order?: SortingOrder, column?: KeysOf<T>): T[] {
        if (!values || values.length <= 1 || !order) {
            return values;
        }

        if (!column) {
            /** sort 1D array */
            const result = [...values].sort();
            return order === SortingOrders.asc ? result : result.reverse();
        }

        return orderBy(values, [column], [order]);
    }

    setSortingOption(value: SortingOption<T>): void {
        this._sortingOption$.next(value);
    }

    defaultSort(values: T[]): T[] {
        return SortingService.sort(values, this.sortingOption?.order, this.sortingOption?.column);
    }

    toggleSort(column: KeysOf<T>): void {
        const sameColumn = this.sortingOption?.column === column;
        const order = sameColumn ? SortingOrders.inverseOf(this.sortingOption?.order) : SortingOrders.asc;

        this._sortingOption$.next({ column, order });
    }
}