import {
  Component,
  Input,
  ViewChild,
  Output,
  EventEmitter,
  OnInit,
  forwardRef,
  OnChanges
} from '@angular/core';
import * as moment from 'moment/moment';
import { NG_VALUE_ACCESSOR, ControlValueAccessor } from '@angular/forms';
import { FieldsetWrapper } from '../../wrappers/fieldset-wrapper';
import { SamDateComponent } from '../date/date.component';
import { SamTimeComponent } from '../time/time.component';
import {SamFormService} from '../../form-service';

const MY_VALUE_ACCESSOR: any = {
  provide: NG_VALUE_ACCESSOR,
  useExisting: forwardRef(() => SamDateTimeComponent),
  multi: true
};

/**
 * The <sam-date-time> component is a DateTime entry portion of a form
 */
@Component({
  selector: 'sam-date-time',
  templateUrl: 'date-time.template.html',
  providers: [ MY_VALUE_ACCESSOR ]
})
export class SamDateTimeComponent
  implements OnInit, OnChanges, ControlValueAccessor {
  public INPUT_FORMAT: string = 'Y-M-DTH:m';
  /**
   * Sets starting value for input
   */
  @Input() label: string;
  /**
   * Sets name attribute value
   */
  @Input() name: string;
  /**
   * Sets hint text
   */
  @Input() hint: string;
  /**
   * Sets error message string to display for invalid values
   */
  @Input() errorMessage: string;
  /**
   * Sets disabled attribute value for input
   */
  @Input() disabled: boolean = false;  
  /**
   * Sets the formControl to check validations and update error messaged
   */
  @Input() control;
  /**
  * Toggles validations to display with SamFormService events
  */
  @Input() useFormService: boolean;
  public value;
  public time: string = undefined;
  public date: string = undefined;

  @ViewChild('dateComponent') public dateComponent: SamDateComponent;
  @ViewChild('timeComponent') public timeComponent: SamTimeComponent;
  @ViewChild(FieldsetWrapper) public wrapper;

  public onChange: Function;
  public onTouched: Function;

  constructor(private samFormService: SamFormService) { }

  ngOnInit() {
    if (!this.name) {
      throw new Error('SamDateTimeComponent requires a\
       [name] input for 508 compliance');
    }

    if (this.control) {
      if (!this.useFormService) {
        this.control.statusChanges.subscribe(() => {
          this.wrapper.formatErrors(this.control);
        });
        this.wrapper.formatErrors(this.control);
      } else {
        this.samFormService.formEventsUpdated$.subscribe((evt: any) => {
          if ((!evt.root || evt.root === this.control.root)
            && evt.eventType && evt.eventType === 'submit') {
            this.wrapper.formatErrors(this.control);
          } else if ((!evt.root || evt.root === this.control.root)
            && evt.eventType && evt.eventType === 'reset') {
            this.wrapper.clearError();
          }
        });
      }
    }
  }

  ngOnChanges() {
    this.parseValueString();
  }

  parseValueString(): void {
    if (this.value) {
      // use the more forgiving format (that doesn't need 0 padding) for inputs
      const m = moment(this.value, this.INPUT_FORMAT);
      if (m.isValid()) {
        this.time = m.format(this.timeComponent.OUTPUT_FORMAT);
        this.date = m.format(this.dateComponent.OUTPUT_FORMAT);
      } else {
        console.error('[value] for sam-date-time is invalid');
      }
    }
  }

  emitChanges(val: string): void {
    this.value = val;
    // only when this component is used as a FormControl will change be
    // registered
    if (this.onChange) {
      this.onChange(val);
    }
  }

  dateBlur() {
    this.timeComponent.hourV.nativeElement.focus();
  }

  onInputChange(): void {
    if (this.dateComponent.isClean() && this.timeComponent.isClean()) {
      this.emitChanges(undefined);
    } else if (this.dateComponent.isValid() && this.timeComponent.isValid()) {
      this.emitChanges(`${this.date}T${this.time}`);
    } else {
      this.emitChanges('Invalid Date Time');
    }
  }

  resetInput() {
    this.date = '';
    this.time = '';
  }

  registerOnChange(fn) {
    this.onChange = fn;
  }

  registerOnTouched(fn) {
    this.onTouched = fn;
  }

  setDisabledState(disabled) {
    this.disabled = disabled;
  }

  writeValue(value) {
    if (value) {
      this.value = value;
    } else {
      this.value = '';
      this.resetInput();
    }
    this.parseValueString();
  }

}