//@flow
import React from "react";
import { translate } from "react-i18next";
import type { Links } from "@scm-manager/ui-types";
import { apiClient, SubmitButton, Loading, ErrorNotification } from "../";

type RenderProps = {
  readOnly: boolean,
  initialConfiguration: ConfigurationType,
  onConfigurationChange: (ConfigurationType, boolean) => void
};

type Props = {
  link: string,
  render: (props: RenderProps) => any, // ???

  // context props
  t: string => string
};

type ConfigurationType = {
  _links: Links
} & Object;

type State = {
  error?: Error,
  fetching: boolean,
  modifying: boolean,
  contentType?: string,
  configChanged: boolean,

  configuration?: ConfigurationType,
  modifiedConfiguration?: ConfigurationType,
  valid: boolean
};

/**
 * GlobalConfiguration uses the render prop pattern to encapsulate the logic for
 * synchronizing the configuration with the backend.
 */
class Configuration extends React.Component<Props, State> {
  constructor(props: Props) {
    super(props);
    this.state = {
      fetching: true,
      modifying: false,
      configChanged: false,
      valid: false
    };
  }

  componentDidMount() {
    const { link } = this.props;

    apiClient
      .get(link)
      .then(this.captureContentType)
      .then(response => response.json())
      .then(this.loadConfig)
      .catch(this.handleError);
  }

  captureContentType = (response: Response) => {
    const contentType = response.headers.get("Content-Type");
    this.setState({
      contentType
    });
    return response;
  };

  getContentType = (): string => {
    const { contentType } = this.state;
    return contentType ? contentType : "application/json";
  };

  handleError = (error: Error) => {
    this.setState({
      error,
      fetching: false,
      modifying: false
    });
  };

  loadConfig = (configuration: ConfigurationType) => {
    this.setState({
      configuration,
      fetching: false,
      error: undefined
    });
  };

  getModificationUrl = (): ?string => {
    const { configuration } = this.state;
    if (configuration) {
      const links = configuration._links;
      if (links && links.update) {
        return links.update.href;
      }
    }
  };

  isReadOnly = (): boolean => {
    const modificationUrl = this.getModificationUrl();
    return !modificationUrl;
  };

  configurationChanged = (configuration: ConfigurationType, valid: boolean) => {
    this.setState({
      modifiedConfiguration: configuration,
      valid
    });
  };

  modifyConfiguration = (event: Event) => {
    event.preventDefault();

    this.setState({ modifying: true });

    const { modifiedConfiguration } = this.state;

    apiClient
      .put(
        this.getModificationUrl(),
        modifiedConfiguration,
        this.getContentType()
      )
      .then(() => this.setState({ modifying: false, configChanged: true, valid: false }))
      .catch(this.handleError);
  };

  renderConfigChangedNotification = () => {
    if (this.state.configChanged) {
      return (
        <div className="notification is-primary">
          <button
            className="delete"
            onClick={() => this.setState({ configChanged: false })}
          />
          {this.props.t("config-form.submit-success-notification")}
        </div>
      );
    }
    return null;
  };

  render() {
    const { t } = this.props;
    const { fetching, error, configuration, modifying, valid } = this.state;

    if (error) {
      return <ErrorNotification error={error} />;
    } else if (fetching || !configuration) {
      return <Loading />;
    } else {
      const readOnly = this.isReadOnly();

      const renderProps: RenderProps = {
        readOnly,
        initialConfiguration: configuration,
        onConfigurationChange: this.configurationChanged
      };

      return (
        <>
          {this.renderConfigChangedNotification()}
          <form onSubmit={this.modifyConfiguration}>
            {this.props.render(renderProps)}
            <hr />
            <SubmitButton
              label={t("config-form.submit")}
              disabled={!valid || readOnly}
              loading={modifying}
            />
          </form>
        </>
      );
    }
  }
}

export default translate("config")(Configuration);