sparebank1_actual_budget_integration/src/bank/sparebank1.ts

// TODO move types
import { BANK_INITIAL_REFRESH_TOKEN } from "@/../config.ts"
import logger from "@/logger.ts"
import dayjs from "dayjs"
import { Database } from "better-sqlite3"
import { fetchToken, insertTokens, TokenResponse } from "@/bank/db/queries.ts"
import * as Api from "./sparebank1Api.ts"

export interface OAuthTokenResponse {
  access_token: string
  expires_in: number
  refresh_token_expires_in: number
  refresh_token_absolute_expires_in: number
  token_type: "Bearer"
  refresh_token: string
}

export interface Transaction {
  id: string
  date: string
  amount: number
  description: string
  cleanedDescription: string
  remoteAccountName: string

  [key: string]: string | number | boolean | unknown
}

export type Bank = Sparebank1

export interface Sparebank1 {
  transactionsPastDay: (
    accountKeys: ReadonlyArray<string> | string,
  ) => Promise<ReadonlyArray<Transaction>>
}

export class Sparebank1Impl implements Sparebank1 {
  private static baseUrl = "https://api.sparebank1.no"
  private readonly db: Database

  constructor(db: Database) {
    this.db = db
  }

  private async getAccessToken(): Promise<string> {
    const accessToken = fetchToken(this.db, "access-token")

    if (accessToken && this.isValidToken(accessToken)) {
      return accessToken.token
    }
    const response = await this.fetchNewTokens()
    return response.access_token
  }

  private isValidToken(tokenResponse: TokenResponse): boolean {
    return dayjs() < tokenResponse.expires_at
  }

  private async getRefreshToken(): Promise<string> {
    const tokenResponse = fetchToken(this.db, "refresh-token")
    if (!tokenResponse) {
      return BANK_INITIAL_REFRESH_TOKEN
    } else if (this.isValidToken(tokenResponse)) {
      return tokenResponse.token
    }
    // TODO clear database, if refresh token is invalid, will cause Exceptions on each call
    throw new Error("Refresh token is expired. Create a new one")
  }

  async fetchNewTokens(): Promise<OAuthTokenResponse> {
    const refreshToken = await this.getRefreshToken()
    const result = await Api.refreshToken(refreshToken)

    if (result.status === "failure") {
      throw new Error("Failed to fetch refresh token")
    }
    const oAuthToken = result.data

    insertTokens(this.db, oAuthToken)
    return oAuthToken
  }

  async transactionsPastDay(
    accountKeys: ReadonlyArray<string> | string,
  ): Promise<ReadonlyArray<Transaction>> {
    const today = dayjs()
    const lastDay = today.subtract(1, "day")
    const queries = new URLSearchParams({
      // TODO allow multiple accountKeys
      accountKey:
        typeof accountKeys === "string" ? accountKeys : accountKeys[0],
      fromDate: lastDay.toString(),
      toDate: today.toString(),
    })

    const accessToken = await this.getAccessToken()
    const response = await fetch(
      `${Sparebank1Impl.baseUrl}/transactions?${queries}`,
      {
        headers: {
          Authorization: `Bearer ${accessToken}`,
        },
      },
    )
    if (response.ok) {
      return response.json()
    } else {
      logger.warn(
        `transactionsPastDay returned a ${response.status} with the text ${response.statusText}`,
      )
      return []
    }
  }
}