import React, {PropTypes, Component} from 'react';
import {PREFIX_CLS} from './Constants';
import Select from '../select';
import {Group, Button} from '../radio';

function noop() {}

class Header extends Component {
  getYearSelectElement(year) {
    const {yearSelectOffset, yearSelectTotal, locale, prefixCls} = this.props;
    const start = year - yearSelectOffset;
    const end = start + yearSelectTotal;
    const suffix = locale.year === '年' ? '年' : '';

    const options = [];
    for (let index = start; index < end; index++) {
      options.push(<Option key={`${index}`}>{index + suffix}</Option> );
    }
    return (
      <Select
        size="small"
        dropdownMatchSelectWidth={false}
        className={`${prefixCls}-year-select`}
        onChange={this.onYearChange.bind(this)}
        value={String(year)}>
        { options }
      </Select>
    );
  }
  getMonthSelectElement(month) {
    const props = this.props;
    const months = props.locale.format.months;
    const {prefixCls} = props;
    const options = [];

    for (let index = 0; index < 12; index++) {
      options.push(<Option key={`${index}`}>{months[index]}</Option>);
    }

    return (
      <Select
        size="small"
        dropdownMatchSelectWidth={false}
        className={`${prefixCls}-month-select`}
        value={String(month)}
        onChange={this.onMonthChange.bind(this)}>
        { options }
      </Select>
    );
  }
  onYearChange(year) {
    const newValue = this.props.value.clone();
    newValue.setYear(parseInt(year, 10));
    this.props.onValueChange(newValue);
  }

  onMonthChange(month) {
    const newValue = this.props.value.clone();
    newValue.setMonth(parseInt(month, 10));
    this.props.onValueChange(newValue);
  }
  onTypeChange(e) {
    this.props.onTypeChange(e.target.value);
  }
  render() {
    const {type, value, prefixCls, locale} = this.props;

    const yearSelect = this.getYearSelectElement(value.getYear());

    const monthSelect = type === 'date' ? this.getMonthSelectElement(value.getMonth()) : null;

    const typeSwitch = (
      <Group onChange={this.onTypeChange.bind(this)} value={type}>
        <Button value="date">{locale.month}</Button>
        <Button value="month">{locale.year}</Button>
      </Group>
    );

    return (
      <div className={`${prefixCls}-header`}>
        { yearSelect }
        { monthSelect }
        { typeSwitch }
      </div>
    );
  }
}
Header.propTypes = {
  value: PropTypes.object,
  locale: PropTypes.object,
  yearSelectOffset: PropTypes.number,
  yearSelectTotal: PropTypes.number,
  onValueChange: PropTypes.func,
  onTypeChange: PropTypes.func,
  prefixCls: PropTypes.string,
  selectPrefixCls: PropTypes.string,
  type: PropTypes.string,
};
Header.defaultProps = {
  prefixCls: `${PREFIX_CLS}-header`,
  yearSelectOffset: 10,
  yearSelectTotal: 20,
  onValueChange: noop,
  onTypeChange: noop,
};

export default Header;