import { EventEmitter } from '@angular/core';

import { ArrayCollection } from './ArrayCollection';
import { PagedCollection } from './PagedCollection';
import { CollectionEvent } from './CollectionEvent';

export class PagedArrayCollection<T> extends ArrayCollection<T> implements PagedCollection<T> {
    _page: number = 1;
    _numberOfPages: number = 1;
    _pageSize: number = 10;

    constructor(source: Array<T> = []) {
        super(source);
    }

    get numberOfPages(): number {
        let result: number = this.source.length / this.pageSize;
        result = Math.ceil(result);
        return result;
    }

    get page(): number {
        return this._page;
    }

    set page(value: number) {
        this._page = value;
        this.refresh();
    }

    get pageSize(): number {
        return this._pageSize;
    }

    set pageSize(value: number) {
        this._pageSize = value;
        this.refresh();
    }

    next(): number {
        if (this.page === this.numberOfPages) { return this.page; }
        this.page++;
        return this.page;
    }

    prev(): number {
        if (this._page === 1) { return this.page; }
        this.page--;
        return this.page;
    }

    first(): number {
        if (this.page === 1) { return this.page; }
        this.page = 1;
        return this.page;
    }

    last(): number {
        if (this.page === this.numberOfPages) { return this.page; }
        this.page = this.numberOfPages;
        return this.page;
    }

    refresh(): void {
        this.filterData = this.isEditing ? this.editData.slice() : this.source.slice();
        for (let item of this._sort.reverse()) {
            this.sortOn(item.field, item.reverse);
        }
        for (let key in this._filter) {
            if (key) {
                this.filterOn(key, this._filter[key]);
            }
        }
        if (this.page >= 0) {
            let start = (this.page - 1) * this.pageSize;
            let end = start + this.pageSize;
            let result = this.filterData.slice(start, end);
            this.onDataChange(new CollectionEvent(CollectionEvent.CHANGE, result));
        } else {
            this.onDataChange(new CollectionEvent(CollectionEvent.CHANGE, this.filterData));
        }
    }
}