// NG2
import { Component, EventEmitter, Input, Output, OnInit, OnChanges, SimpleChanges } from '@angular/core';
import { coerceBooleanProperty } from '@angular/cdk/coercion';
// APP
import { NovoLabelService } from '../../../../services/novo-label-service';

@Component({
    selector: 'novo-pagination',
    template: `
        <h5 class="rows">{{label}}</h5>
        <novo-select [options]="rowOptions" [placeholder]="labels.select" [(ngModel)]="itemsPerPage" (onSelect)="onPageSizeChanged($event)" data-automation-id="pager-select"></novo-select>
        <span class="spacer"></span>
        <ul class="pager" data-automation-id="pager">
            <li class="page" (click)="selectPage(page-1)" [ngClass]="{'disabled': noPrevious()}"><i class="bhi-previous" data-automation-id="pager-previous"></i></li>
            <li class="page" [ngClass]="{active: p.number==page}" [class.disabled]="disablePageSelection" *ngFor="let p of pages" (click)="selectPage(p.number)">{{p.text}}</li>
            <li class="page" (click)="selectPage(page+1)" [ngClass]="{'disabled': noNext()}"><i class="bhi-next" data-automation-id="pager-next"></i></li>
        </ul>
  `
})
export class Pagination implements OnInit, OnChanges {
    @Input() page: number;
    @Input() totalItems: number;
    @Input() itemsPerPage: number = 10;
    @Input() rowOptions: any;
    @Input() label: string;
    @Input()
    get disablePageSelection(): boolean { return this.pageSelectDisabled; }
    set disablePageSelection(val: boolean) {
        this.pageSelectDisabled = coerceBooleanProperty(val);
    }
    @Output() pageChange: EventEmitter<any> = new EventEmitter();
    @Output() itemsPerPageChange: EventEmitter<any> = new EventEmitter();
    @Output() onPageChange: EventEmitter<any> = new EventEmitter();

    public pageSelectDisabled: boolean;
    maxPagesDisplayed: number = 5;
    totalPages: number;
    pages: Array<any>;

    constructor(public labels: NovoLabelService) {
    }

    ngOnInit() {
        this.label = this.label || this.labels.itemsPerPage;
        this.rowOptions = this.rowOptions || this.getDefaultRowOptions();
    }

    ngOnChanges(changes?: SimpleChanges) {
        this.page = this.page || 1;
        this.totalPages = this.calculateTotalPages();
        this.pages = this.getPages(this.page, this.totalPages);
    }

    getDefaultRowOptions() {
        return [
            { value: 10, label: '10' },
            { value: 25, label: '25' },
            { value: 50, label: '50' },
            { value: 100, label: '100' }
        ];
    }

    onPageSizeChanged(event) {
        this.page = 1;
        this.itemsPerPage = event.selected;
        this.totalPages = this.calculateTotalPages();
        this.pages = this.getPages(this.page, this.totalPages);
        this.pageChange.emit(this.page);
        this.itemsPerPageChange.emit(this.itemsPerPage);
        this.onPageChange.emit({
            page: this.page,
            itemsPerPage: this.itemsPerPage
        });
    }

    selectPage(page, event?: any) {
        if (event) {
            event.preventDefault();
        }

        this.page = page;
        this.pages = this.getPages(this.page, this.totalPages);
        this.pageChange.emit(this.page);
        this.onPageChange.emit({
            page: this.page,
            itemsPerPage: this.itemsPerPage
        });
    }

    noPrevious() {
        return this.page === 1;
    }

    noNext() {
        return this.page === this.totalPages;
    }

    // Create page object used in template
    makePage(number, text, isActive) {
        return {
            number: number,
            text: text,
            active: isActive
        };
    }

    getPages(currentPage, totalPages) {
        let pages = [];
        // Default page limits
        let startPage = 1;
        let endPage = totalPages;
        const isMaxSized = this.maxPagesDisplayed < totalPages;

        // recompute if maxPagesDisplayed
        if (isMaxSized) {
            // Current page is displayed in the middle of the visible ones
            startPage = Math.max(currentPage - Math.floor(this.maxPagesDisplayed / 2), 1);
            endPage = startPage + this.maxPagesDisplayed - 1;

            // Adjust if limit is exceeded
            if (endPage > totalPages) {
                endPage = totalPages;
                startPage = endPage - this.maxPagesDisplayed + 1;
            }
        }

        // Add page number links
        for (let number = startPage; number <= endPage; number++) {
            const page = this.makePage(number, number.toString(), number === currentPage);
            pages.push(page);
        }
        return pages;
    }

    calculateTotalPages() {
        const totalPages = this.itemsPerPage < 1 ? 1 : Math.ceil(this.totalItems / this.itemsPerPage);
        return Math.max(totalPages || 0, 1);
    }
}