import { Injectable } from '@nestjs/common';
import { HTTPError } from 'got';
import { QueryError } from 'src/modules/data_sources/query.error';
import { QueryResult } from 'src/modules/data_sources/query_result.type';
import { QueryService } from 'src/modules/data_sources/query_service.interface';
import { isEmpty } from 'lodash';
import { readFileSync } from 'fs';
import * as tls from 'tls';
const urrl = require('url');
const got = require('got');

interface RestAPIResult extends QueryResult {
  request?: Array<object> | object;
  response?: Array<object> | object;
}

@Injectable()
export default class RestapiQueryService implements QueryService {
  /* Headers of the source will be overridden by headers of the query */
  headers(sourceOptions: any, queryOptions: any, hasDataSource: boolean): object {
    const _headers = (queryOptions.headers || []).filter((o) => {
      return o.some((e) => !isEmpty(e));
    });

    if (!hasDataSource) return Object.fromEntries(_headers);

    const headerData = _headers.concat(sourceOptions.headers || []);

    const headers = Object.fromEntries(headerData);
    Object.keys(headers).forEach((key) => (headers[key] === '' ? delete headers[key] : {}));

    return headers;
  }

  /* Body params of the source will be overridden by body params of the query */
  body(sourceOptions: any, queryOptions: any, hasDataSource: boolean): object {
    const _body = (queryOptions.body || []).filter((o) => {
      return o.some((e) => !isEmpty(e));
    });

    if (!hasDataSource) return Object.fromEntries(_body);

    const bodyParams = _body.concat(sourceOptions.body || []);
    return Object.fromEntries(bodyParams);
  }

  /* Search params of the source will be overridden by Search params of the query */
  searchParams(sourceOptions: any, queryOptions: any, hasDataSource: boolean): object {
    const _urlParams = (queryOptions.url_params || []).filter((o) => {
      return o.some((e) => !isEmpty(e));
    });

    if (!hasDataSource) return Object.fromEntries(_urlParams);

    const urlParams = _urlParams.concat(sourceOptions.url_params || []);
    return Object.fromEntries(urlParams);
  }

  async run(sourceOptions: any, queryOptions: any, dataSourceId: string): Promise<RestAPIResult> {
    /* REST API queries can be adhoc or associated with a REST API datasource */
    const hasDataSource = dataSourceId !== undefined;
    const requiresOauth = sourceOptions['auth_type'] === 'oauth2';

    const headers = this.headers(sourceOptions, queryOptions, hasDataSource);

    /* Chceck if OAuth tokens exists for the source if query requires OAuth */
    if (requiresOauth) {
      const tokenData = sourceOptions['tokenData'];

      if (!tokenData) {
        const tooljetHost = process.env.TOOLJET_HOST;
        const authUrl = `${sourceOptions['auth_url']}?response_type=code&client_id=${sourceOptions['client_id']}&redirect_uri=${tooljetHost}/oauth2/authorize&scope=${sourceOptions['scopes']}`;

        return {
          status: 'needs_oauth',
          data: { auth_url: authUrl },
        };
      } else {
        const accessToken = tokenData['access_token'];
        if (sourceOptions['add_token_to'] === 'header') {
          const headerPrefix = sourceOptions['header_prefix'];
          headers['Authorization'] = `${headerPrefix}${accessToken}`;
        }
      }
    }

    let result = {};
    let requestObject = {};
    let responseObject = {};

    /* Prefixing the base url of datasouce if datasource exists */
    const url = hasDataSource ? `${sourceOptions.url}${queryOptions.url || ''}` : queryOptions.url;

    const method = queryOptions['method'];
    const json = method !== 'get' ? this.body(sourceOptions, queryOptions, hasDataSource) : undefined;
    const paramsFromUrl = urrl.parse(url, true).query;
    try {
      const response = await got(url, {
        method,
        headers,
        ...this.fetchHttpsCertsForCustomCA(),
        searchParams: {
          ...paramsFromUrl,
          ...this.searchParams(sourceOptions, queryOptions, hasDataSource),
        },
        json,
      });
      result = JSON.parse(response.body);
      requestObject = {
        requestUrl: response.request.requestUrl,
        method: response.request.options.method,
        headers: response.request.options.headers,
        params: urrl.parse(response.request.requestUrl, true).query,
      };
      responseObject = {
        body: response.body,
        statusCode: response.statusCode,
      };
    } catch (error) {
      console.log(error);

      if (error instanceof HTTPError) {
        result = {
          requestObject: {
            requestUrl: error.request.requestUrl,
            requestHeaders: error.request.options.headers,
            requestParams: urrl.parse(error.request.requestUrl, true).query,
          },
          responseObject: {
            statusCode: error.response.statusCode,
            responseBody: error.response.body,
          },
        };
      }
      throw new QueryError('Query could not be completed', error.message, result);
    }

    return {
      status: 'ok',
      data: result,
      request: requestObject,
      response: responseObject,
    };
  }

  /* This function fetches the access token from the token url set in REST API (oauth) datasource */
  async fetchOAuthToken(sourceOptions: any, code: string): Promise<any> {
    const tooljetHost = process.env.TOOLJET_HOST;
    const accessTokenUrl = sourceOptions['access_token_url'];

    const customParams = Object.fromEntries(sourceOptions['custom_auth_params']);
    Object.keys(customParams).forEach((key) => (customParams[key] === '' ? delete customParams[key] : {}));

    const response = await got(accessTokenUrl, {
      method: 'post',
      json: {
        code,
        client_id: sourceOptions['client_id'],
        client_secret: sourceOptions['client_secret'],
        grant_type: sourceOptions['grant_type'],
        redirect_uri: `${tooljetHost}/oauth2/authorize`,
        ...this.fetchHttpsCertsForCustomCA(),
        ...customParams,
      },
    });

    const result = JSON.parse(response.body);
    return { access_token: result['access_token'] };
  }

  fetchHttpsCertsForCustomCA() {
    if (!process.env.NODE_EXTRA_CA_CERTS) return {};

    return {
      https: {
        certificateAuthority: [...tls.rootCertificates, readFileSync(process.env.NODE_EXTRA_CA_CERTS)].join('\n'),
      },
    };
  }
}