// @flow
import * as React from 'react';
import PropTypes from 'prop-types';


const contextTypes = {
  insertCss: PropTypes.func,
};
type StylesContextType = KeyValueOfType<Object>;
const { Provider, Consumer } = React.createContext<StylesContextType>({});
const getThemeFromContext = <Theme>(id: string, context: StylesContextType): Theme | void => {
  const theme = context[id];

  if (!theme) {
    return;
  }

  return (theme: any);
};


type StyleThemeResolverType<Theme, Props> = (Props, Theme | void) => Theme | void;

type StyleThemeParams<Theme, Props> = {
  id: string,
  styles: Array<Object>,
  resolveTheme?: StyleThemeResolverType<Theme, Props>,
};

type StyleThemeProviderType<Theme, Props> = {
  <Props>(Theme): (React.ComponentType<Props>) => React.ComponentType<Props>,
  $$styleThemeId: string,
  $$styleThemeStyles: Array<Object>,
  $$styleThemeResolver: StyleThemeResolverType<Theme, Props>,
}

export function createStyleTheme<Theme, Props>(
  { id, styles, resolveTheme }: StyleThemeParams<Theme, Props>,
): StyleThemeProviderType<Theme, Props> {
  const defaultResolver = (props, styleTheme) => styleTheme;
  const resolver = resolveTheme || defaultResolver;

  const styleThemeProvider = (theme) => (Component) => (props) => (
    <Consumer>
      {(context) => (
        <Provider value={{ ...context, [id]: theme }}>
          <Component {...props} />
        </Provider>
      )}
    </Consumer>
  );

  styleThemeProvider.$$styleThemeId = id;
  styleThemeProvider.$$styleThemeStyles = styles;
  styleThemeProvider.$$styleThemeResolver = resolver;

  return styleThemeProvider;
}


export type StyleThemePropType = {
  s: Object,
};

type StylesType<Theme, Props> =
  | CssModuleType
  | StyleThemeProviderType<Theme, Props>;

function withStyles<Theme: Object, Props: Object>(styles: StylesType<Theme, Props>) {
  let getStyles;
  let resolveStyles: (Props, StylesContextType) => Theme | void;

  if (typeof styles.$$styleThemeResolver === 'function') {
    const resolver = styles.$$styleThemeResolver;

    getStyles = () => styles.$$styleThemeStyles;
    resolveStyles = (props, context) => {
      const stylesTheme = getThemeFromContext(styles.$$styleThemeId, context);

      return resolver(props, stylesTheme);
    };
  } else {
    getStyles = () => [styles];
    resolveStyles = () => {};
  }

  return function wrapWithStyles(
    ComposedComponent: React.ComponentType<Props & StyleThemePropType>,
  ): React.ComponentType<Props> {
    class WithStyles extends React.PureComponent<Props> {
      removeCss: Function;

      constructor(props, context) {
        super(props, context);

        this.removeCss = context.insertCss(...getStyles());
      }

      componentWillUnmount() {
        if (this.removeCss) {
          setTimeout(this.removeCss, 0);
        }
      }

      render() {
        return (
          <Consumer>
            {(context) => {
              const s = resolveStyles(this.props, context);

              return (
                <ComposedComponent s={s} {...this.props} />
              );
            }}
          </Consumer>
        );
      }
    }

    const displayName = ComposedComponent.displayName || ComposedComponent.name || '';

    WithStyles.displayName = `WithStyles(${displayName})`;
    WithStyles.contextTypes = contextTypes;

    return WithStyles;
  };
}

export default withStyles;