import axios, { AxiosRequestConfig, AxiosResponse, Method } from 'axios';
import { RestClientType } from '../types';

import { signMessage } from './node-support';
import {
  RestClientOptions,
  serializeParams,
  getRestBaseUrl,
} from './requestUtils';
import { neverGuard } from './websocket-util';

interface SignedRequest<T extends object | undefined = {}> {
  originalParams: T;
  paramsWithSign?: T & { sign: string };
  serializedParams: string;
  sign: string;
  queryParamsWithSign: string;
  timestamp: number;
  recvWindow: number;
}

interface UnsignedRequest<T extends object | undefined = {}> {
  originalParams: T;
  paramsWithSign: T;
}

type SignMethod = 'bitget';

export default abstract class BaseRestClient {
  private options: RestClientOptions;
  private baseUrl: string;
  private globalRequestOptions: AxiosRequestConfig;
  private apiKey: string | undefined;
  private apiSecret: string | undefined;
  private apiPass: string | undefined;

  /** Defines the client type (affecting how requests & signatures behave) */
  abstract getClientType(): RestClientType;

  /**
   * Create an instance of the REST client. Pass API credentials in the object in the first parameter.
   * @param {RestClientOptions} [restClientOptions={}] options to configure REST API connectivity
   * @param {AxiosRequestConfig} [networkOptions={}] HTTP networking options for axios
   */
  constructor(
    restOptions: RestClientOptions = {},
    networkOptions: AxiosRequestConfig = {}
  ) {
    this.options = {
      recvWindow: 5000,
      /** Throw errors if any request params are empty */
      strictParamValidation: false,
      ...restOptions,
    };

    this.globalRequestOptions = {
      // in ms == 5 minutes by default
      timeout: 1000 * 60 * 5,
      // custom request options based on axios specs - see: https://github.com/axios/axios#request-config
      ...networkOptions,
      headers: {
        'X-CHANNEL-API-CODE': '3tem',
        'Content-Type': 'application/json',
        locale: 'en-US',
      },
    };

    this.baseUrl = getRestBaseUrl(false, restOptions);
    this.apiKey = this.options.apiKey;
    this.apiSecret = this.options.apiSecret;
    this.apiPass = this.options.apiPass;

    // Throw if one of the 3 values is missing, but at least one of them is set
    const credentials = [this.apiKey, this.apiSecret, this.apiPass];
    if (
      credentials.includes(undefined) &&
      credentials.some((v) => typeof v === 'string')
    ) {
      throw new Error(
        'API Key, Secret & Passphrase are ALL required to use the authenticated REST client'
      );
    }
  }

  get(endpoint: string, params?: any) {
    return this._call('GET', endpoint, params, true);
  }

  getPrivate(endpoint: string, params?: any) {
    return this._call('GET', endpoint, params, false);
  }

  post(endpoint: string, params?: any) {
    return this._call('POST', endpoint, params, true);
  }

  postPrivate(endpoint: string, params?: any) {
    return this._call('POST', endpoint, params, false);
  }

  deletePrivate(endpoint: string, params?: any) {
    return this._call('DELETE', endpoint, params, false);
  }

  /**
   * @private Make a HTTP request to a specific endpoint. Private endpoints are automatically signed.
   */
  private async _call(
    method: Method,
    endpoint: string,
    params?: any,
    isPublicApi?: boolean
  ): Promise<any> {
    // Sanity check to make sure it's only ever prefixed by one forward slash
    const requestUrl = [this.baseUrl, endpoint].join(
      endpoint.startsWith('/') ? '' : '/'
    );

    // Build a request and handle signature process
    const options = await this.buildRequest(
      method,
      endpoint,
      requestUrl,
      params,
      isPublicApi
    );

    // console.log('full request: ', options);

    // Dispatch request
    return axios(options)
      .then((response) => {
        // console.log('response: ', response.data);
        // console.error('res: ', response);
        // if (response.data && response.data?.code !== API_ERROR_CODE.SUCCESS) {
        //   throw response.data;
        // }
        if (response.status == 200) {
          if (
            typeof response.data?.code === 'string' &&
            response.data?.code !== '00000'
          ) {
            throw { response };
          }
          return response.data;
        }
        throw { response };
      })
      .catch((e) => this.parseException(e));
  }

  /**
   * @private generic handler to parse request exceptions
   */
  parseException(e: any): unknown {
    if (this.options.parseExceptions === false) {
      throw e;
    }

    // Something happened in setting up the request that triggered an Error
    if (!e.response) {
      if (!e.request) {
        throw e.message;
      }

      // request made but no response received
      throw e;
    }

    // The request was made and the server responded with a status code
    // that falls out of the range of 2xx
    const response: AxiosResponse = e.response;
    // console.error('err: ', response?.data);

    throw {
      code: response.status,
      message: response.statusText,
      body: response.data,
      headers: response.headers,
      requestOptions: {
        ...this.options,
        apiPass: 'omittedFromError',
        apiSecret: 'omittedFromError',
      },
    };
  }

  /**
   * @private sign request and set recv window
   */
  private async signRequest<T extends object | undefined = {}>(
    data: T,
    endpoint: string,
    method: Method,
    signMethod: SignMethod
  ): Promise<SignedRequest<T>> {
    const timestamp = Date.now();

    const res: SignedRequest<T> = {
      originalParams: {
        ...data,
      },
      sign: '',
      timestamp,
      recvWindow: 0,
      serializedParams: '',
      queryParamsWithSign: '',
    };

    if (!this.apiKey || !this.apiSecret) {
      return res;
    }

    // It's possible to override the recv window on a per rquest level
    const strictParamValidation = this.options.strictParamValidation;

    if (signMethod === 'bitget') {
      const signRequestParams =
        method === 'GET'
          ? serializeParams(data, strictParamValidation, '?')
          : JSON.stringify(data) || '';

      const paramsStr =
        timestamp + method.toUpperCase() + endpoint + signRequestParams;

      // console.log('sign params: ', paramsStr);

      res.sign = await signMessage(paramsStr, this.apiSecret, 'base64');
      res.queryParamsWithSign = signRequestParams;
      return res;
    }

    console.error(
      new Date(),
      neverGuard(signMethod, `Unhandled sign method: "${signMessage}"`)
    );

    return res;
  }

  private async prepareSignParams<TParams extends object | undefined>(
    method: Method,
    endpoint: string,
    signMethod: SignMethod,
    params?: TParams,
    isPublicApi?: true
  ): Promise<UnsignedRequest<TParams>>;
  private async prepareSignParams<TParams extends object | undefined>(
    method: Method,
    endpoint: string,
    signMethod: SignMethod,
    params?: TParams,
    isPublicApi?: false | undefined
  ): Promise<SignedRequest<TParams>>;
  private async prepareSignParams<TParams extends object | undefined>(
    method: Method,
    endpoint: string,
    signMethod: SignMethod,
    params?: TParams,
    isPublicApi?: boolean
  ) {
    if (isPublicApi) {
      return {
        originalParams: params,
        paramsWithSign: params,
      };
    }

    if (!this.apiKey || !this.apiSecret) {
      throw new Error('Private endpoints require api and private keys set');
    }

    return this.signRequest(params, endpoint, method, signMethod);
  }

  /** Returns an axios request object. Handles signing process automatically if this is a private API call */
  private async buildRequest(
    method: Method,
    endpoint: string,
    url: string,
    params?: any,
    isPublicApi?: boolean
  ): Promise<AxiosRequestConfig> {
    const options: AxiosRequestConfig = {
      ...this.globalRequestOptions,
      url: url,
      method: method,
    };

    for (const key in params) {
      if (typeof params[key] === 'undefined') {
        delete params[key];
      }
    }

    if (isPublicApi || !this.apiKey || !this.apiPass) {
      return {
        ...options,
        params: params,
      };
    }

    const signResult = await this.prepareSignParams(
      method,
      endpoint,
      'bitget',
      params,
      isPublicApi
    );

    if (!options.headers) {
      options.headers = {};
    }
    options.headers['ACCESS-KEY'] = this.apiKey;
    options.headers['ACCESS-PASSPHRASE'] = this.apiPass;
    options.headers['ACCESS-TIMESTAMP'] = signResult.timestamp;
    options.headers['ACCESS-SIGN'] = signResult.sign;
    options.headers['Content-Type'] = 'application/json';

    if (method === 'GET') {
      return {
        ...options,
        url: options.url + signResult.queryParamsWithSign,
      };
    }

    return {
      ...options,
      data: params,
    };
  }
}