/**
 * Copyright 2013-2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule LinkedValueUtils
 * @typechecks static-only
 */

"use strict";

var ReactPropTypes = require('ReactPropTypes');

var invariant = require('invariant');

var hasReadOnlyValue = {
  'button': true,
  'checkbox': true,
  'image': true,
  'hidden': true,
  'radio': true,
  'reset': true,
  'submit': true
};

function _assertSingleLink(input) {
  invariant(
    input.props.checkedLink == null || input.props.valueLink == null,
    'Cannot provide a checkedLink and a valueLink. If you want to use ' +
    'checkedLink, you probably don\'t want to use valueLink and vice versa.'
  );
}
function _assertValueLink(input) {
  _assertSingleLink(input);
  invariant(
    input.props.value == null && input.props.onChange == null,
    'Cannot provide a valueLink and a value or onChange event. If you want ' +
    'to use value or onChange, you probably don\'t want to use valueLink.'
  );
}

function _assertCheckedLink(input) {
  _assertSingleLink(input);
  invariant(
    input.props.checked == null && input.props.onChange == null,
    'Cannot provide a checkedLink and a checked property or onChange event. ' +
    'If you want to use checked or onChange, you probably don\'t want to ' +
    'use checkedLink'
  );
}

/**
 * @param {SyntheticEvent} e change event to handle
 */
function _handleLinkedValueChange(e) {
  /*jshint validthis:true */
  this.props.valueLink.requestChange(e.target.value);
}

/**
  * @param {SyntheticEvent} e change event to handle
  */
function _handleLinkedCheckChange(e) {
  /*jshint validthis:true */
  this.props.checkedLink.requestChange(e.target.checked);
}

/**
 * Provide a linked `value` attribute for controlled forms. You should not use
 * this outside of the ReactDOM controlled form components.
 */
var LinkedValueUtils = {
  Mixin: {
    propTypes: {
      value: function(props, propName, componentName) {
        if (!props[propName] ||
            hasReadOnlyValue[props.type] ||
            props.onChange ||
            props.readOnly ||
            props.disabled) {
          return;
        }
        return new Error(
          'You provided a `value` prop to a form field without an ' +
          '`onChange` handler. This will render a read-only field. If ' +
          'the field should be mutable use `defaultValue`. Otherwise, ' +
          'set either `onChange` or `readOnly`.'
        );
      },
      checked: function(props, propName, componentName) {
        if (!props[propName] ||
            props.onChange ||
            props.readOnly ||
            props.disabled) {
          return;
        }
        return new Error(
          'You provided a `checked` prop to a form field without an ' +
          '`onChange` handler. This will render a read-only field. If ' +
          'the field should be mutable use `defaultChecked`. Otherwise, ' +
          'set either `onChange` or `readOnly`.'
        );
      },
      onChange: ReactPropTypes.func
    }
  },

  /**
   * @param {ReactComponent} input Form component
   * @return {*} current value of the input either from value prop or link.
   */
  getValue: function(input) {
    if (input.props.valueLink) {
      _assertValueLink(input);
      return input.props.valueLink.value;
    }
    return input.props.value;
  },

  /**
   * @param {ReactComponent} input Form component
   * @return {*} current checked status of the input either from checked prop
   *             or link.
   */
  getChecked: function(input) {
    if (input.props.checkedLink) {
      _assertCheckedLink(input);
      return input.props.checkedLink.value;
    }
    return input.props.checked;
  },

  /**
   * @param {ReactComponent} input Form component
   * @return {function} change callback either from onChange prop or link.
   */
  getOnChange: function(input) {
    if (input.props.valueLink) {
      _assertValueLink(input);
      return _handleLinkedValueChange;
    } else if (input.props.checkedLink) {
      _assertCheckedLink(input);
      return _handleLinkedCheckChange;
    }
    return input.props.onChange;
  }
};

module.exports = LinkedValueUtils;
