import { makeRequest } from './services/network_service';
import {
  DataExporterAppPluginMeta,
  DataExporterPluginMetaJSONData,
  DataExporterPluginMetaSecureJSONData,
} from './types';

import { getBackendSrv } from '@grafana/runtime';

import axios from 'axios';

export type UpdateGrafanaPluginSettingsProps = {
  jsonData?: Partial<DataExporterPluginMetaJSONData>;
  secureJsonData?: Partial<DataExporterPluginMetaSecureJSONData>;
};

type InstallPluginResponse<DataExporterAPIResponse = any> = Pick<
  DataExporterPluginMetaSecureJSONData,
  'grafanaToken'
> & {
  dataExporterAPIResponse: DataExporterAPIResponse;
};

export type PluginConnectedStatusResponse = {
  version: string;
};

class PluginState {
  static GRAFANA_PLUGIN_SETTINGS_URL = '/api/plugins/corpglory-dataexporter-app/settings';
  static grafanaBackend = getBackendSrv();

  static generateInvalidDataExporterApiURLErrorMsg = (dataExporterApiUrl: string): string =>
    `Could not communicate with your DataExporter API at ${dataExporterApiUrl}.\nValidate that the URL is correct, your DataExporter API is running, and that it is accessible from your Grafana instance.`;

  static generateUnknownErrorMsg = (dataExporterApiUrl: string): string =>
    `An unknown error occured when trying to install the plugin. Are you sure that your DataExporter API URL, ${dataExporterApiUrl}, is correct?\nRefresh your page and try again, or try removing your plugin configuration and reconfiguring.`;

  static getHumanReadableErrorFromDataExporterError = (e: any, dataExporterApiUrl: string): string => {
    let errorMsg: string;
    const unknownErrorMsg = this.generateUnknownErrorMsg(dataExporterApiUrl);
    const consoleMsg = `occured while trying to install the plugin w/ the DataExporter backend`;

    if (axios.isAxiosError(e)) {
      const statusCode = e.response?.status;

      console.warn(`An HTTP related error ${consoleMsg}`, e.response);

      if (statusCode === 502) {
        // 502 occurs when the plugin-proxy cannot communicate w/ the DataExporter API using the provided URL
        errorMsg = this.generateInvalidDataExporterApiURLErrorMsg(dataExporterApiUrl);
      } else if (statusCode === 400) {
        /**
         * A 400 is 'bubbled-up' from the DataExporter API. It indicates one of three cases:
         * 1. there is a communication error when DataExporter API tries to contact Grafana's API
         * 2. there is an auth error when DataExporter API tries to contact Grafana's API
         * 3. (likely rare) user inputs an DataExporterApiUrl that is not RFC 1034/1035 compliant
         *
         * Check if the response body has an 'error' JSON attribute, if it does, assume scenario 1 or 2
         * Use the error message provided to give the user more context/helpful debugging information
         */
        errorMsg = e.response?.data?.error || unknownErrorMsg;
      } else {
        // this scenario shouldn't occur..
        errorMsg = unknownErrorMsg;
      }
    } else {
      // a non-axios related error occured.. this scenario shouldn't occur...
      console.warn(`An unknown error ${consoleMsg}`, e);
      errorMsg = unknownErrorMsg;
    }
    return errorMsg;
  };

  static getHumanReadableErrorFromGrafanaProvisioningError = (e: any, dataExporterApiUrl: string): string => {
    let errorMsg: string;

    if (axios.isAxiosError(e)) {
      // The user likely put in a bogus URL for the DataExporter API URL
      console.warn('An HTTP related error occured while trying to provision the plugin w/ Grafana', e.response);
      errorMsg = this.generateInvalidDataExporterApiURLErrorMsg(dataExporterApiUrl);
    } else {
      // a non-axios related error occured.. this scenario shouldn't occur...
      console.warn('An unknown error occured while trying to provision the plugin w/ Grafana', e);
      errorMsg = this.generateUnknownErrorMsg(dataExporterApiUrl);
    }
    return errorMsg;
  };

  static getGrafanaPluginSettings = async (): Promise<DataExporterAppPluginMeta> =>
    this.grafanaBackend.get<DataExporterAppPluginMeta>(this.GRAFANA_PLUGIN_SETTINGS_URL);

  static updateGrafanaPluginSettings = async (data: UpdateGrafanaPluginSettingsProps, enabled = true) =>
    this.grafanaBackend.post(this.GRAFANA_PLUGIN_SETTINGS_URL, { ...data, enabled, pinned: true });

  static createGrafanaToken = async () => {
    const baseUrl = '/api/auth/keys';
    const keys = await this.grafanaBackend.get(baseUrl);
    const existingKey = keys.find((key: { id: number; name: string; role: string }) => key.name === 'DataExporter');

    if (existingKey) {
      await this.grafanaBackend.delete(`${baseUrl}/${existingKey.id}`);
    }

    return await this.grafanaBackend.post(baseUrl, {
      name: 'DataExporter',
      role: 'Admin',
      secondsToLive: null,
    });
  };

  static timeout = (pollCount: number) => new Promise((resolve) => setTimeout(resolve, 10 * 2 ** pollCount));

  static connectBackend = async <RT>(): Promise<InstallPluginResponse<RT>> => {
    // TODO: try to disable success alerts from Grafana API
    const { key: grafanaToken } = await this.createGrafanaToken();
    await this.updateGrafanaPluginSettings({ secureJsonData: { grafanaToken } });
    const dataExporterAPIResponse = await makeRequest<RT>(`/connect`, {
      method: 'POST',
    });
    return { grafanaToken, dataExporterAPIResponse };
  };

  static installPlugin = async (dataExporterApiUrl: string): Promise<string | null> => {
    let pluginInstallationDataExporterResponse: InstallPluginResponse<{ version: string }>;

    // Step 1. Try provisioning the plugin w/ the Grafana API
    try {
      await this.updateGrafanaPluginSettings({ jsonData: { dataExporterApiUrl } });
    } catch (e) {
      return this.getHumanReadableErrorFromGrafanaProvisioningError(e, dataExporterApiUrl);
    }

    /**
     * Step 2:
     * - Create a grafana token
     * - store that token in the Grafana plugin settings
     * - configure the plugin in DataExporter's backend
     */
    try {
      pluginInstallationDataExporterResponse = await this.connectBackend<{ version: string }>();
    } catch (e) {
      return this.getHumanReadableErrorFromDataExporterError(e, dataExporterApiUrl);
    }

    // Step 3. reprovision the Grafana plugin settings, storing information that we get back from DataExporter's backend
    try {
      const { grafanaToken } = pluginInstallationDataExporterResponse;

      await this.updateGrafanaPluginSettings({
        jsonData: {
          dataExporterApiUrl,
        },
        secureJsonData: {
          grafanaToken,
        },
      });
    } catch (e) {
      return this.getHumanReadableErrorFromGrafanaProvisioningError(e, dataExporterApiUrl);
    }

    return null;
  };

  static checkIfPluginIsConnected = async (
    dataExporterApiUrl: string
  ): Promise<PluginConnectedStatusResponse | string> => {
    try {
      const resp = await makeRequest<PluginConnectedStatusResponse>(`/status`, {
        method: 'GET',
      });

      // TODO: check if the server version is compatible with the plugin
      if (resp.version) {
        return resp;
      } else {
        throw new Error(`Something is working at ${dataExporterApiUrl} but it's not DataExporter backend`);
      }
    } catch (e) {
      return this.getHumanReadableErrorFromDataExporterError(e, dataExporterApiUrl);
    }
  };

  static resetPlugin = (): Promise<void> => {
    /**
     * mark both of these objects as Required.. this will ensure that we are resetting every attribute back to null
     * and throw a type error in the event that DataExporterPluginMetaJSONData or DataExporterPluginMetaSecureJSONData is updated
     * but we forget to add the attribute here
     */
    const jsonData: Required<DataExporterPluginMetaJSONData> = {
      dataExporterApiUrl: null,
    };
    const secureJsonData: Required<DataExporterPluginMetaSecureJSONData> = {
      grafanaToken: null,
    };

    return this.updateGrafanaPluginSettings({ jsonData, secureJsonData }, false);
  };
}

export default PluginState;