var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

function _objectWithoutProperties(obj, keys) { var target = {}; for (var i in obj) { if (keys.indexOf(i) >= 0) continue; if (!Object.prototype.hasOwnProperty.call(obj, i)) continue; target[i] = obj[i]; } return target; }

import React from 'react';
import invariant from 'invariant';
import { routerShape } from './PropTypes';
import { ContextSubscriber } from './ContextUtils';

var _React$PropTypes = React.PropTypes,
    bool = _React$PropTypes.bool,
    object = _React$PropTypes.object,
    string = _React$PropTypes.string,
    func = _React$PropTypes.func,
    oneOfType = _React$PropTypes.oneOfType;


function isLeftClickEvent(event) {
  return event.button === 0;
}

function isModifiedEvent(event) {
  return !!(event.metaKey || event.altKey || event.ctrlKey || event.shiftKey);
}

// TODO: De-duplicate against hasAnyProperties in createTransitionManager.
function isEmptyObject(object) {
  for (var p in object) {
    if (Object.prototype.hasOwnProperty.call(object, p)) return false;
  }return true;
}

function resolveToLocation(to, router) {
  return typeof to === 'function' ? to(router.location) : to;
}

/**
 * A <Link> is used to create an <a> element that links to a route.
 * When that route is active, the link gets the value of its
 * activeClassName prop.
 *
 * For example, assuming you have the following route:
 *
 *   <Route path="/posts/:postID" component={Post} />
 *
 * You could use the following component to link to that route:
 *
 *   <Link to={`/posts/${post.id}`} />
 *
 * Links may pass along location state and/or query string parameters
 * in the state/query props, respectively.
 *
 *   <Link ... query={{ show: true }} state={{ the: 'state' }} />
 */
var Link = React.createClass({
  displayName: 'Link',


  mixins: [ContextSubscriber('router')],

  contextTypes: {
    router: routerShape
  },

  propTypes: {
    to: oneOfType([string, object, func]),
    query: object,
    hash: string,
    state: object,
    activeStyle: object,
    activeClassName: string,
    onlyActiveOnIndex: bool.isRequired,
    onClick: func,
    target: string
  },

  getDefaultProps: function getDefaultProps() {
    return {
      onlyActiveOnIndex: false,
      style: {}
    };
  },
  handleClick: function handleClick(event) {
    if (this.props.onClick) this.props.onClick(event);

    if (event.defaultPrevented) return;

    var router = this.context.router;

    !router ? process.env.NODE_ENV !== 'production' ? invariant(false, '<Link>s rendered outside of a router context cannot navigate.') : invariant(false) : void 0;

    if (isModifiedEvent(event) || !isLeftClickEvent(event)) return;

    // If target prop is set (e.g. to "_blank"), let browser handle link.
    /* istanbul ignore if: untestable with Karma */
    if (this.props.target) return;

    event.preventDefault();

    router.push(resolveToLocation(this.props.to, router));
  },
  render: function render() {
    var _props = this.props,
        to = _props.to,
        activeClassName = _props.activeClassName,
        activeStyle = _props.activeStyle,
        onlyActiveOnIndex = _props.onlyActiveOnIndex,
        props = _objectWithoutProperties(_props, ['to', 'activeClassName', 'activeStyle', 'onlyActiveOnIndex']);

    // Ignore if rendered outside the context of router to simplify unit testing.


    var router = this.context.router;


    if (router) {
      // If user does not specify a `to` prop, return an empty anchor tag.
      if (!to) {
        return React.createElement('a', props);
      }

      var toLocation = resolveToLocation(to, router);
      props.href = router.createHref(toLocation);

      if (activeClassName || activeStyle != null && !isEmptyObject(activeStyle)) {
        if (router.isActive(toLocation, onlyActiveOnIndex)) {
          if (activeClassName) {
            if (props.className) {
              props.className += ' ' + activeClassName;
            } else {
              props.className = activeClassName;
            }
          }

          if (activeStyle) props.style = _extends({}, props.style, activeStyle);
        }
      }
    }

    return React.createElement('a', _extends({}, props, { onClick: this.handleClick }));
  }
});

export default Link;