import { Component, ContentChildren, QueryList, AfterContentInit, Input, Output, EventEmitter } from '@angular/core';
import { Tab } from './tab/tab.component';
import { ViewEncapsulation } from '@angular/core';
import { trigger, state, style, transition, animate, keyframes } from '@angular/core';

@Component({
    selector: 'tabs',
    templateUrl: './tabs.component.html',
    styleUrls: ['./tabs.component.less'],
    encapsulation: ViewEncapsulation.None,
    animations: [
        trigger('indicatorAnimation', [
            transition(':enter', [style({ transform: 'translateY(-50%)', opacity: 0 }), animate('250ms', style({ transform: 'translateY(0)', opacity: 1 })) ]),
            transition(':leave', [style({ opacity: 1 }), animate('500ms', style({ opacity: 0 })) ])
        ])
    ]
})
export class Tabs implements AfterContentInit {

    @Input() tabStyle: string;
    @Input() hideIndicationOnTabChange?: boolean = false;
    @ContentChildren(Tab) tabs: QueryList<Tab>;
    @Output() tabChanged: EventEmitter<Tab> = new EventEmitter<Tab>();


    ngAfterContentInit() {  
        //after contentChildren are set, determine active tab. If no active tab set, activate the first one
        let activeTabs = this.tabs.filter((tab) => tab.active);
 
        if (activeTabs.length === 0) {
            this.selectTab(this.tabs.first);
        }
    }

    selectTab(tab: Tab) {
        //activate the tab the user clicked.
        this.tabs.toArray().forEach(tab => {
            tab.active = false;
            if (this.hideIndicationOnTabChange && tab.indication) {
                tab.indication = null;
            }
        });
        tab.active = true;
        this.tabChanged.emit(tab);
    }

    triggerTabChange(tabTitle) {
        this.tabs.toArray().forEach(tab => {
            tab.active = (tab.title == tabTitle) ? true : false;
        });
    }

    setTabIndication(tabTitle:string, indication?:number) {
        let selectedTab: Tab = this.tabs.toArray().find(tab => tab.title == tabTitle);
        selectedTab.indication = indication || null;
    }

}