/**
 * Copyright (c) 2015-present, 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 StatusBar
 * @flow
 */
'use strict';

const React = require('React');
const ColorPropType = require('ColorPropType');
const Platform = require('Platform');

const processColor = require('processColor');

const StatusBarManager = require('NativeModules').StatusBarManager;

/**
 * Status bar style
 */
export type StatusBarStyle = $Enum<{
  /**
   * Default status bar style
   */
  'default': string,
  /**
   * Dark background style
   */
  'light-content': string,
}>;

/**
 * Status bar animation
 */
export type StatusBarAnimation = $Enum<{
  /**
   * No animation
   */
  'none': string,
  /**
   * Fade animation
   */
  'fade': string,
  /**
   * Slide animation
   */
  'slide': string,
}>;

type DefaultProps = {
  animated: boolean;
};

/**
 * Merges the prop stack with the default values.
 */
function mergePropsStack(propsStack: Array<Object>, defaultValues: Object): Object {
  return propsStack.reduce((prev, cur) => {
    for (let prop in cur) {
      if (cur[prop] != null) {
        prev[prop] = cur[prop];
      }
    }
    return prev;
  }, Object.assign({}, defaultValues));
}

/**
 * Returns an object to insert in the props stack from the props
 * and the transition/animation info.
 */
function createStackEntry(props: any): any {
  return {
    backgroundColor: props.backgroundColor != null ? {
      value: props.backgroundColor,
      animated: props.animated,
    } : null,
    barStyle: props.barStyle != null ? {
      value: props.barStyle,
      animated: props.animated,
    } : null,
    translucent: props.translucent,
    hidden: props.hidden != null ? {
      value: props.hidden,
      animated: props.animated,
      transition: props.showHideTransition,
    } : null,
    networkActivityIndicatorVisible: props.networkActivityIndicatorVisible,
  };
}

/**
 * Component to control the app status bar.
 *
 * ### Usage with Navigator
 *
 * It is possible to have multiple `StatusBar` components mounted at the same
 * time. The props will be merged in the order the `StatusBar` components were
 * mounted. One use case is to specify status bar styles per route using `Navigator`.
 *
 * ```
 *  <View>
 *    <StatusBar
 *      backgroundColor="blue"
 *      barStyle="light-content"
 *    />
 *    <Navigator
 *      initialRoute={{statusBarHidden: true}}
 *      renderScene={(route, navigator) =>
 *        <View>
 *          <StatusBar hidden={route.statusBarHidden} />
 *          ...
 *        </View>
 *      }
 *    />
 *  </View>
 * ```
 *
 * ### Imperative API
 *
 * For cases where using a component is not ideal, there is also an imperative
 * API exposed as static functions on the component. It is however not recommended
 * to use the static API and the component for the same prop because any value
 * set by the static API will get overriden by the one set by the component in
 * the next render.
 */
class StatusBar extends React.Component {
  props: {
    hidden?: boolean,
    animated?: boolean,
    backgroundColor?: $FlowFixMe,
    translucent?: boolean,
    barStyle?: 'default' | 'light-content',
    networkActivityIndicatorVisible?: boolean,
    showHideTransition?: 'fade' | 'slide',
  };

  static _propsStack = [];

  static _defaultProps = createStackEntry({
    animated: false,
    showHideTransition: 'fade',
    backgroundColor: 'black',
    barStyle: 'default',
    translucent: false,
    hidden: false,
    networkActivityIndicatorVisible: false,
  });

  // Timer for updating the native module values at the end of the frame.
  static _updateImmediate = null;

  // The current merged values from the props stack.
  static _currentValues = null;

  // TODO(janic): Provide a real API to deal with status bar height. See the
  // discussion in #6195.
  /**
   * The current height of the status bar on the device.
   *
   * @platform android
   */
  static currentHeight = StatusBarManager.HEIGHT;

  // Provide an imperative API as static functions of the component.
  // See the corresponding prop for more detail.

  /**
   * Show or hide the status bar
   * @param hidden The dialog's title.
   * @param animation Optional animation when
   *    changing the status bar hidden property.
   */
  static setHidden(hidden: boolean, animation?: StatusBarAnimation) {
    animation = animation || 'none';
    StatusBar._defaultProps.hidden.value = hidden;
    if (Platform.OS === 'ios') {
      StatusBarManager.setHidden(hidden, animation);
    } else if (Platform.OS === 'android') {
      StatusBarManager.setHidden(hidden);
    }
  }

  /**
   * Set the status bar style
   * @param style Status bar style to set
   * @param animated Animate the style change.
   */
  static setBarStyle(style: StatusBarStyle, animated?: boolean) {
    if (Platform.OS !== 'ios') {
      console.warn('`setBarStyle` is only available on iOS');
      return;
    }
    animated = animated || false;
    StatusBar._defaultProps.barStyle.value = style;
    StatusBarManager.setStyle(style, animated);
  }

  /**
   * Control the visibility of the network activity indicator
   * @param visible Show the indicator.
   */
  static setNetworkActivityIndicatorVisible(visible: boolean) {
    if (Platform.OS !== 'ios') {
      console.warn('`setNetworkActivityIndicatorVisible` is only available on iOS');
      return;
    }
    StatusBar._defaultProps.networkActivityIndicatorVisible = visible;
    StatusBarManager.setNetworkActivityIndicatorVisible(visible);
  }

  /**
   * Set the background color for the status bar
   * @param color Background color.
   * @param animated Animate the style change.
   */
  static setBackgroundColor(color: string, animated?: boolean) {
    if (Platform.OS !== 'android') {
      console.warn('`setBackgroundColor` is only available on Android');
      return;
    }
    animated = animated || false;
    StatusBar._defaultProps.backgroundColor.value = color;
    StatusBarManager.setColor(processColor(color), animated);
  }

  /**
   * Control the translucency of the status bar
   * @param translucent Set as translucent.
   */
  static setTranslucent(translucent: boolean) {
    if (Platform.OS !== 'android') {
      console.warn('`setTranslucent` is only available on Android');
      return;
    }
    StatusBar._defaultProps.translucent = translucent;
    StatusBarManager.setTranslucent(translucent);
  }

  static propTypes = {
    /**
     * If the status bar is hidden.
     */
    hidden: React.PropTypes.bool,
    /**
     * If the transition between status bar property changes should be animated.
     * Supported for backgroundColor, barStyle and hidden.
     */
    animated: React.PropTypes.bool,
    /**
     * The background color of the status bar.
     * @platform android
     */
    backgroundColor: ColorPropType,
    /**
     * If the status bar is translucent.
     * When translucent is set to true, the app will draw under the status bar.
     * This is useful when using a semi transparent status bar color.
     *
     * @platform android
     */
    translucent: React.PropTypes.bool,
    /**
     * Sets the color of the status bar text.
     *
     * @platform ios
     */
    barStyle: React.PropTypes.oneOf([
      'default',
      'light-content',
    ]),
    /**
     * If the network activity indicator should be visible.
     *
     * @platform ios
     */
    networkActivityIndicatorVisible: React.PropTypes.bool,
    /**
     * The transition effect when showing and hiding the status bar using the `hidden`
     * prop. Defaults to 'fade'.
     *
     * @platform ios
     */
    showHideTransition: React.PropTypes.oneOf([
      'fade',
      'slide',
    ]),
  };

  static defaultProps = {
    animated: false,
    showHideTransition: 'fade',
  };

  _stackEntry = null;

  componentDidMount() {
    // Every time a StatusBar component is mounted, we push it's prop to a stack
    // and always update the native status bar with the props from the top of then
    // stack. This allows having multiple StatusBar components and the one that is
    // added last or is deeper in the view hierachy will have priority.
    this._stackEntry = createStackEntry(this.props);
    StatusBar._propsStack.push(this._stackEntry);
    this._updatePropsStack();
  }

  componentWillUnmount() {
    // When a StatusBar is unmounted, remove itself from the stack and update
    // the native bar with the next props.
    // $FlowFixMe found when converting React.createClass to ES6
    const index = StatusBar._propsStack.indexOf(this._stackEntry);
    StatusBar._propsStack.splice(index, 1);

    this._updatePropsStack();
  }

  componentDidUpdate() {
    // $FlowFixMe found when converting React.createClass to ES6
    const index = StatusBar._propsStack.indexOf(this._stackEntry);
    this._stackEntry = createStackEntry(this.props);
    StatusBar._propsStack[index] = this._stackEntry;

    this._updatePropsStack();
  }

  /**
   * Updates the native status bar with the props from the stack.
   */
  _updatePropsStack = () => {
    // Send the update to the native module only once at the end of the frame.
    clearImmediate(StatusBar._updateImmediate);
    StatusBar._updateImmediate = setImmediate(() => {
      const oldProps = StatusBar._currentValues;
      const mergedProps = mergePropsStack(StatusBar._propsStack, StatusBar._defaultProps);

      // Update the props that have changed using the merged values from the props stack.
      if (Platform.OS === 'ios') {
        if (!oldProps || oldProps.barStyle.value !== mergedProps.barStyle.value) {
          StatusBarManager.setStyle(
            mergedProps.barStyle.value,
            mergedProps.barStyle.animated,
          );
        }
        if (!oldProps || oldProps.hidden.value !== mergedProps.hidden.value) {
          StatusBarManager.setHidden(
            mergedProps.hidden.value,
            mergedProps.hidden.animated ?
              mergedProps.hidden.transition :
              'none',
          );
        }

        if (!oldProps || oldProps.networkActivityIndicatorVisible !== mergedProps.networkActivityIndicatorVisible) {
          StatusBarManager.setNetworkActivityIndicatorVisible(
            mergedProps.networkActivityIndicatorVisible
          );
        }
      } else if (Platform.OS === 'android') {
        if (!oldProps || oldProps.backgroundColor.value !== mergedProps.backgroundColor.value) {
          StatusBarManager.setColor(
            processColor(mergedProps.backgroundColor.value),
            mergedProps.backgroundColor.animated,
          );
        }
        if (!oldProps || oldProps.hidden.value !== mergedProps.hidden.value) {
          StatusBarManager.setHidden(mergedProps.hidden.value);
        }
        if (!oldProps || oldProps.translucent !== mergedProps.translucent) {
          StatusBarManager.setTranslucent(mergedProps.translucent);
        }
      }
      // Update the current prop values.
      StatusBar._currentValues = mergedProps;
    });
  };

  render(): ?ReactElement<any> {
    return null;
  }
}

module.exports = StatusBar;
