import React from 'react';
import moment from 'moment';
import PropTypes from 'prop-types';
import RangeCalendar from 'rc-calendar/lib/RangeCalendar';
import RcDatePicker from 'rc-calendar/lib/Picker';
import classNames from 'classnames';
import assign from 'object-assign';
import Icon from '../icon';
import { getLocaleCode } from '../_util/getLocale';
import warning from '../_util/warning';

function getShowDateFromValue(value: moment.Moment[]): moment.Moment[] | undefined {
  const [ start, end ] = value;
  // value could be an empty array, then we should not reset showDate
  if (!start && !end) {
    return;
  }
  const newEnd = end && end.isSame(start, 'month') ? end.clone().add(1, 'month') : end;
  return [start, newEnd];
}

function formatValue(value: moment.Moment | undefined, format: string): string {
  return (value && value.format(format)) || '';
}

function pickerValueAdapter(value?: moment.Moment | moment.Moment[]): moment.Moment[] | undefined {
  if (!value) { return; }
  if (Array.isArray(value)) {
    return value;
  }
  return [value, value.clone().add(1, 'month')];
}

export default class RangePicker extends React.Component<any, any> {
  static contextTypes = {
      antLocale: PropTypes.object,
  };
  static defaultProps = {
    prefixCls: 'ant-calendar',
    allowClear: true,
    showToday: false,
  };

  constructor(props) {
    super(props);
    const value = props.value || props.defaultValue || [];
    if (
      value[0] && !moment.isMoment(value[0]) ||
      value[1] && !moment.isMoment(value[1])
    ) {
      throw new Error(
        'The value/defaultValue of RangePicker must be a moment object array after `antd@2.0`, ' +
        'see: http://u.ant.design/date-picker-value',
      );
    }
    this.state = {
      value,
      open: props.open,
    };
  }

  componentWillReceiveProps(nextProps) {
    if ('value' in nextProps) {
      const value = nextProps.value || [];
      this.setState({ value, showDate: getShowDateFromValue(value) });
    }
    if ('open' in nextProps) {
      this.setState({
        open: nextProps.open,
      });
    }
  }

  clearSelection = (e) => {
    e.preventDefault();
    e.stopPropagation();
    this.setState({ value: [] });
    this.handleChange([]);
  }

  handleChange = (value: moment.Moment[]) => {
    const props = this.props;
    if (!('value' in props)) {
      this.setState({ value, showDate: getShowDateFromValue(value) });
    }
    props.onChange(value, [
      formatValue(value[0], props.format),
      formatValue(value[1], props.format),
    ]);
  }

  handleOpenChange = (open) => {
    this.setState({ open });

    const { onOpenChange } = this.props;
    if (onOpenChange) {
      onOpenChange(open);
    }
  }

  handleShowDateChange = showDate => this.setState({ showDate });

  setValue(value) {
    this.handleChange(value);
    if (!this.props.showTime) {
      this.setState({ open: false });
    }
  }

  renderFooter = () => {
    const { prefixCls, ranges } = this.props;
    if (!ranges) {
      return null;
    }

    const operations = Object.keys(ranges).map((range) => {
      const value = ranges[range];
      return <a key={range} onClick={() => this.setValue(value)}>{range}</a>;
    });
    return (
      <div className={`${prefixCls}-range-quick-selector`}>
        {operations}
      </div>
    );
  }

  render() {
    const { state, props, context } = this;
    const { value, showDate, open } = state;
    const localeCode = getLocaleCode(context);
    if (value && localeCode) {
      if (value[0]) {
        value[0].locale(localeCode);
      }
      if (value[1]) {
        value[1].locale(localeCode);
      }
    }

    const {
      disabledDate, disabledTime, showTime, showToday,
      ranges, prefixCls, popupStyle,
      style, onOk, locale, format,
    } = props;
    warning(!('onOK' in props), 'It should be `RangePicker[onOk]`, instead of `onOK`!');

    const calendarClassName = classNames({
      [`${prefixCls}-time`]: showTime,
      [`${prefixCls}-range-with-ranges`]: ranges,
    });

    // 需要选择时间时，点击 ok 时才触发 onChange
    let pickerChangeHandler = {
      onChange: this.handleChange,
    };
    let calendarHandler: Object = {
      onOk: this.handleChange,
    };
    if (props.timePicker) {
      pickerChangeHandler.onChange = changedValue => this.handleChange(changedValue);
    } else {
      calendarHandler = {};
    }

    const startPlaceholder = ('placeholder' in props)
      ? props.placeholder[0] : locale.lang.rangePlaceholder[0];
    const endPlaceholder = ('placeholder' in props)
      ? props.placeholder[1] : locale.lang.rangePlaceholder[1];

    const calendar = (
      <RangeCalendar
        {...calendarHandler}
        format={format}
        prefixCls={prefixCls}
        className={calendarClassName}
        renderFooter={this.renderFooter}
        timePicker={props.timePicker}
        disabledDate={disabledDate}
        disabledTime={disabledTime}
        dateInputPlaceholder={[startPlaceholder, endPlaceholder]}
        locale={locale.lang}
        onOk={onOk}
        value={showDate || pickerValueAdapter(props.defaultPickerValue) || pickerValueAdapter(moment())}
        onValueChange={this.handleShowDateChange}
        showToday={showToday}
      />
    );

    // default width for showTime
    const pickerStyle = {} as any;
    if (props.showTime) {
      pickerStyle.width = (style && style.width) || 300;
    }

    const clearIcon = (!props.disabled && props.allowClear && value && (value[0] || value[1])) ? (
      <Icon
        type="cross-circle"
        className={`${prefixCls}-picker-clear`}
        onClick={this.clearSelection}
      />
    ) : null;

    const input = ({ value: inputValue }) => {
      const start = inputValue[0];
      const end = inputValue[1];
      return (
        <span className={props.pickerInputClass} disabled={props.disabled}>
          <input
            disabled={props.disabled}
            readOnly
            value={(start && start.format(props.format)) || ''}
            placeholder={startPlaceholder}
            className={`${prefixCls}-range-picker-input`}
          />
          <span className={`${prefixCls}-range-picker-separator`}> ~ </span>
          <input
            disabled={props.disabled}
            readOnly
            value={(end && end.format(props.format)) || ''}
            placeholder={endPlaceholder}
            className={`${prefixCls}-range-picker-input`}
          />
          {clearIcon}
          <span className={`${prefixCls}-picker-icon`} />
        </span>
      );
    };

    return (
      <span className={props.pickerClass} style={assign({}, style, pickerStyle)}>
        <RcDatePicker
          {...props}
          {...pickerChangeHandler}
          calendar={calendar}
          value={value}
          open={open}
          onOpenChange={this.handleOpenChange}
          prefixCls={`${prefixCls}-picker-container`}
          style={popupStyle}
        >
          {input}
        </RcDatePicker>
      </span>
    );
  }
}