import clsx from 'clsx';

import Days from './MonthView/Days.js';
import Weekdays from './MonthView/Weekdays.js';
import WeekNumbers from './MonthView/WeekNumbers.js';

import { CALENDAR_TYPE_LOCALES, CALENDAR_TYPES } from './shared/const.js';

import type { CalendarType } from './shared/types.js';

function getCalendarTypeFromLocale(locale: string | undefined): CalendarType {
  if (locale) {
    for (const [calendarType, locales] of Object.entries(CALENDAR_TYPE_LOCALES)) {
      if (locales.includes(locale)) {
        return calendarType as CalendarType;
      }
    }
  }

  return CALENDAR_TYPES.ISO_8601;
}

type MonthViewProps = {
  /**
   * Type of calendar that should be used. Can be `'gregory`, `'hebrew'`, `'islamic'`, `'iso8601'`. Setting to `"gregory"` or `"hebrew"` will change the first day of the week to Sunday. Setting to `"islamic"` will change the first day of the week to Saturday. Setting to `"islamic"` or `"hebrew"` will make weekends appear on Friday to Saturday.
   *
   * @example 'iso8601'
   */
  calendarType?: CalendarType;
  /**
   *  Whether week numbers shall be shown at the left of MonthView or not.
   *
   * @default false
   * @example true
   */
  showWeekNumbers?: boolean;
  /**
   * Render a custom month view.
   *
   * @example (props, state) => <div>Custom Month View</div>
   */
  render?: (
    props: React.ComponentProps<'div'>,
    state: Omit<MonthViewProps, 'render'>,
  ) => React.ReactElement;
} & Omit<
  React.ComponentProps<typeof Weekdays> &
    React.ComponentProps<typeof WeekNumbers> &
    React.ComponentProps<typeof Days>,
  'calendarType'
>;

/**
 * Displays a given month.
 */
export default function MonthView(props: MonthViewProps): React.ReactElement {
  const { activeStartDate, locale, onMouseLeave, showFixedNumberOfWeeks } = props;
  const {
    calendarType = getCalendarTypeFromLocale(locale),
    formatShortWeekday,
    formatWeekday,
    onClickWeekNumber,
    showWeekNumbers,
    ...childProps
  } = props;

  function renderWeekdays() {
    return (
      <Weekdays
        calendarType={calendarType}
        formatShortWeekday={formatShortWeekday}
        formatWeekday={formatWeekday}
        locale={locale}
        onMouseLeave={onMouseLeave}
      />
    );
  }

  function renderWeekNumbers() {
    if (!showWeekNumbers) {
      return null;
    }

    return (
      <WeekNumbers
        activeStartDate={activeStartDate}
        calendarType={calendarType}
        onClickWeekNumber={onClickWeekNumber}
        onMouseLeave={onMouseLeave}
        showFixedNumberOfWeeks={showFixedNumberOfWeeks}
      />
    );
  }

  function renderDays() {
    return <Days calendarType={calendarType} {...childProps} />;
  }

  const className = 'react-calendar__month-view';

  const { render, ...monthViewProps } = props;

  const rootNodeProps = {
    className: clsx(className, showWeekNumbers ? `${className}--weekNumbers` : ''),
    children: (
      <div
        style={{
          display: 'flex',
          alignItems: 'flex-end',
        }}
      >
        {renderWeekNumbers()}
        <div
          style={{
            flexGrow: 1,
            width: '100%',
          }}
        >
          {renderWeekdays()}
          {renderDays()}
        </div>
      </div>
    ),
  };

  if (render) {
    return render(rootNodeProps, monthViewProps);
  }
  return <div {...rootNodeProps} />;
}