import axios, { AxiosInstance } from 'axios'
import { APIOptions } from './APIOptions'
import { AccessTokenResponse } from './AccessTokenResponse'
import { APIResponse } from './APIResponse'
import * as jwt from 'jsonwebtoken'
import * as moment from 'moment'

// tslint:disable: no-console

export class PrimeTrustAxiosInstance {
  private accessToken: string
  private expiresAt: moment.Moment
  private axiosInstance: AxiosInstance

  private constructor(
    private options: APIOptions,
    private getAccessToken: () => Promise<APIResponse<AccessTokenResponse>>
  ) {
  }

  public static async newInstance(
    options: APIOptions,
    getAccessToken: () => Promise<APIResponse<AccessTokenResponse>>
  ) {
    const instance = new PrimeTrustAxiosInstance(options, getAccessToken)
    await instance.initialize()
    return instance
  }

  public getAxiosInstance(): AxiosInstance {
    return this.axiosInstance
  }

  private async initialize() {
    await this.setAccessToken()

    this.axiosInstance = axios.create({
      baseURL: `${this.options.baseUrl}`,
      // timeout: 1000,
      headers: {
        Authorization: `Bearer ${this.accessToken}`,
      },
    })

    this.axiosInstance.interceptors.request.use(async config => {
      config = await this.checkAccessToken(config)
      return config
    })
  }

  private async checkAccessToken(config) {
    const expiryCheck = moment().add(60, 'seconds')
    if (!this.accessToken || expiryCheck.isAfter(this.expiresAt)) {
      // console.log('checkAccessToken: modifying axios instance')
      await this.initialize()
      config.headers.Authorization = `Bearer ${this.accessToken}`
    }

    return config
  }

  private async setAccessToken(): Promise<APIResponse<AccessTokenResponse>> {
    // return { errors: ['foo'], status: 503}
    const { response, errors, status } = await this.getAccessToken()
    if (errors) {
      return { errors, status }
    }

    // console.log(response)
    const { token } = response
    this.accessToken = token
    // console.log(token)
    // console.log(jwt.decode(token, { complete: true }))
    const { exp } = jwt.decode(token)
    this.expiresAt = moment.unix(exp)
    return { response, status }
  }
}