// @inheritedComponent Paper

import React from 'react';
import PropTypes from 'prop-types';
import classNames from 'classnames';
import Collapse from '../transitions/Collapse';
import Paper from '../Paper';
import withStyles from '../styles/withStyles';
import { isMuiElement } from '../utils/reactHelpers';

export const styles = theme => {
  const transition = {
    duration: theme.transitions.duration.shortest,
  };

  return {
    root: {
      position: 'relative',
      transition: theme.transitions.create(['margin'], transition),
      '&:before': {
        position: 'absolute',
        left: 0,
        top: -1,
        right: 0,
        height: 1,
        content: '""',
        opacity: 1,
        backgroundColor: theme.palette.divider,
        transition: theme.transitions.create(['opacity', 'background-color'], transition),
      },
      '&:first-child': {
        borderTopLeftRadius: 2,
        borderTopRightRadius: 2,
        '&:before': {
          display: 'none',
        },
      },
      '&:last-child': {
        borderBottomLeftRadius: 2,
        borderBottomRightRadius: 2,
      },
      '&$expanded + &': {
        '&:before': {
          display: 'none',
        },
      },
    },
    expanded: {
      margin: `${theme.spacing.unit * 2}px 0`,
      '&:first-child': {
        marginTop: 0,
      },
      '&:last-child': {
        marginBottom: 0,
      },
      '&:before': {
        opacity: 0,
      },
    },
    disabled: {
      backgroundColor: theme.palette.action.disabledBackground,
    },
  };
};

class ExpansionPanel extends React.Component {
  state = {
    expanded: false,
  };

  componentWillMount() {
    const { expanded, defaultExpanded } = this.props;
    this.isControlled = expanded != null;
    this.setState({
      expanded: this.isControlled ? expanded : defaultExpanded,
    });
  }

  componentWillReceiveProps(nextProps) {
    if (this.isControlled) {
      this.setState({
        expanded: nextProps.expanded,
      });
    }
  }

  isControlled = null;

  handleChange = event => {
    const { onChange } = this.props;
    const expanded = !this.state.expanded;

    if (onChange) {
      onChange(event, expanded);
    }

    if (!this.isControlled) {
      this.setState({ expanded });
    }
  };

  render() {
    const {
      children: childrenProp,
      classes,
      className: classNameProp,
      CollapseProps: CollapsePropsProp,
      defaultExpanded,
      disabled,
      expanded: expandedProp,
      onChange,
      ...other
    } = this.props;
    const { expanded } = this.state;

    const className = classNames(
      classes.root,
      {
        [classes.expanded]: expanded,
        [classes.disabled]: disabled,
      },
      classNameProp,
    );

    let summary = null;

    const children = React.Children.map(childrenProp, child => {
      if (!React.isValidElement(child)) {
        return null;
      }

      if (isMuiElement(child, ['ExpansionPanelSummary'])) {
        summary = React.cloneElement(child, {
          disabled,
          expanded,
          onChange: this.handleChange,
        });
        return null;
      }

      return child;
    });

    const CollapseProps = !expanded
      ? {
          'aria-hidden': 'true',
        }
      : null;

    return (
      <Paper className={className} elevation={1} square {...other}>
        {summary}
        <Collapse in={expanded} timeout="auto" {...CollapseProps} {...CollapsePropsProp}>
          {children}
        </Collapse>
      </Paper>
    );
  }
}

ExpansionPanel.propTypes = {
  /**
   * The content of the expansion panel.
   */
  children: PropTypes.node.isRequired,
  /**
   * Useful to extend the style applied to components.
   */
  classes: PropTypes.object.isRequired,
  /**
   * @ignore
   */
  className: PropTypes.string,
  /**
   * Properties applied to the `Collapse` element.
   */
  CollapseProps: PropTypes.object,
  /**
   * If `true`, expands the panel by default.
   */
  defaultExpanded: PropTypes.bool,
  /**
   * If `true`, the panel will be displayed in a disabled state.
   */
  disabled: PropTypes.bool,
  /**
   * If `true`, expands the panel, otherwise collapse it.
   * Setting this prop enables control over the panel.
   */
  expanded: PropTypes.bool,
  /**
   * Callback fired when the expand/collapse state is changed.
   *
   * @param {object} event The event source of the callback
   * @param {boolean} expanded The `expanded` state of the panel
   */
  onChange: PropTypes.func,
};

ExpansionPanel.defaultProps = {
  defaultExpanded: false,
  disabled: false,
};

export default withStyles(styles, { name: 'MuiExpansionPanel' })(ExpansionPanel);