import * as React from 'react';
import { DefaultButton, FocusTrapZone, Callout, DirectionalHint } from 'office-ui-fabric-react';
import { Calendar, DayOfWeek, defaultDayPickerStrings } from '@uifabric/date-time';

export interface ICalendarButtonExampleState {
  showCalendar: boolean;
  selectedDate?: Date;
}

export interface ICalendarButtonExampleProps {
  isDayPickerVisible?: boolean;
  isMonthPickerVisible?: boolean;
  highlightCurrentMonth?: boolean;
  highlightSelectedMonth?: boolean;
  buttonString?: string;
  showMonthPickerAsOverlay?: boolean;
  showGoToToday?: boolean;
}

export class CalendarButtonExample extends React.Component<ICalendarButtonExampleProps, ICalendarButtonExampleState> {
  public static defaultProps: ICalendarButtonExampleProps = {
    showMonthPickerAsOverlay: false,
    isDayPickerVisible: true,
    isMonthPickerVisible: true,
    showGoToToday: true,
    buttonString: 'Click for Calendar',
  };

  private _calendarButtonElement: HTMLElement;

  public constructor(props: ICalendarButtonExampleProps) {
    super(props);

    this.state = {
      showCalendar: false,
      selectedDate: undefined,
    };
  }

  public render(): JSX.Element {
    return (
      <div>
        <div ref={(calendarBtn: HTMLDivElement) => (this._calendarButtonElement = calendarBtn!)}>
          <DefaultButton
            onClick={this._onClick}
            text={!this.state.selectedDate ? this.props.buttonString : this.state.selectedDate.toLocaleDateString()}
          />
        </div>
        {this.state.showCalendar && (
          <Callout
            isBeakVisible={false}
            className="ms-DatePicker-callout"
            gapSpace={0}
            doNotLayer={false}
            target={this._calendarButtonElement}
            directionalHint={DirectionalHint.bottomLeftEdge}
            onDismiss={this._onDismiss}
            setInitialFocus={true}
          >
            <FocusTrapZone isClickableOutsideFocusTrap={true}>
              <Calendar
                onSelectDate={this._onSelectDate}
                onDismiss={this._onDismiss}
                isMonthPickerVisible={this.props.isMonthPickerVisible}
                value={this.state.selectedDate}
                firstDayOfWeek={DayOfWeek.Sunday}
                strings={defaultDayPickerStrings}
                isDayPickerVisible={this.props.isDayPickerVisible}
                highlightCurrentMonth={this.props.highlightCurrentMonth}
                highlightSelectedMonth={this.props.highlightSelectedMonth}
                showMonthPickerAsOverlay={this.props.showMonthPickerAsOverlay}
                showGoToToday={this.props.showGoToToday}
              />
            </FocusTrapZone>
          </Callout>
        )}
      </div>
    );
  }

  private _onClick = (): void => {
    this.setState((prevState: ICalendarButtonExampleState) => {
      prevState.showCalendar = !prevState.showCalendar;
      return prevState;
    });
  };

  private _onDismiss = (): void => {
    this.setState((prevState: ICalendarButtonExampleState) => {
      prevState.showCalendar = false;
      return prevState;
    });
  };

  private _onSelectDate = (date: Date): void => {
    this.setState((prevState: ICalendarButtonExampleState) => {
      prevState.showCalendar = false;
      prevState.selectedDate = date;
      return prevState;
    });
  };
}