import { AmountJson, Amounts } from "../amounts.js";
import { HttpRequestLibrary } from "../http-common.js";
import { HttpStatusCode } from "../http-status-codes.js";
import { createPlatformHttpLib } from "../http.js";
import { FailCasesByMethod, ResultByMethod, opEmptySuccess, opKnownFailure, opSuccess, opUnknownFailure } from "../operation.js";
import { TalerErrorCode } from "../taler-error-codes.js";
import { codecForTalerErrorDetail } from "../wallet-types.js";
import {
  AccessToken,
  TalerBankConversionApi,
  UserAndToken,
  codecForCashinConversionResponse,
  codecForCashoutConversionResponse,
  codecForConversionBankConfig
} from "./types.js";
import { makeBearerTokenAuthHeader } from "./utils.js";

export type TalerBankConversionResultByMethod<prop extends keyof TalerBankConversionHttpClient> = ResultByMethod<TalerBankConversionHttpClient, prop>
export type TalerBankConversionErrorsByMethod<prop extends keyof TalerBankConversionHttpClient> = FailCasesByMethod<TalerBankConversionHttpClient, prop>

/**
 * The API is used by the wallets.
 */
export class TalerBankConversionHttpClient {
  httpLib: HttpRequestLibrary;

  constructor(
    readonly baseUrl: string,
    httpClient?: HttpRequestLibrary,
  ) {
    this.httpLib = httpClient ?? createPlatformHttpLib();
  }

  /**
   * https://docs.taler.net/core/api-bank-conversion-info.html#get--config
   * 
   */
  async getConfig() {
    const url = new URL(`config`, this.baseUrl);
    const resp = await this.httpLib.fetch(url.href, {
      method: "GET"
    });
    switch (resp.status) {
      case HttpStatusCode.Ok: return opSuccess(resp, codecForConversionBankConfig())
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  /**
   * https://docs.taler.net/core/api-bank-conversion-info.html#get--cashin-rate
   * 
   */
  async getCashinRate(conversion: { debit?: AmountJson, credit?: AmountJson }) {
    const url = new URL(`cashin-rate`, this.baseUrl);
    if (conversion.debit) {
      url.searchParams.set("amount_debit", Amounts.stringify(conversion.debit))
    }
    if (conversion.credit) {
      url.searchParams.set("amount_credit", Amounts.stringify(conversion.credit))
    }
    const resp = await this.httpLib.fetch(url.href, {
      method: "GET",
    });
    switch (resp.status) {
      case HttpStatusCode.Ok: return opSuccess(resp, codecForCashinConversionResponse())
      case HttpStatusCode.BadRequest: {
        const body = await resp.json()
        const details = codecForTalerErrorDetail().decode(body)
        switch (details.code) {
          case TalerErrorCode.GENERIC_PARAMETER_MISSING: return opKnownFailure("missing-params", resp);
          case TalerErrorCode.GENERIC_PARAMETER_MALFORMED: return opKnownFailure("wrong-calculation", resp);
          case TalerErrorCode.GENERIC_CURRENCY_MISMATCH: return opKnownFailure("wrong-currency", resp);
          default: return opUnknownFailure(resp, body)
        }
      }
      case HttpStatusCode.Conflict: return opKnownFailure("amount-too-small", resp);
      case HttpStatusCode.NotImplemented: return opKnownFailure("conversion-not-supported", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  /**
   * https://docs.taler.net/core/api-bank-conversion-info.html#get--cashout-rate
   * 
   */
  async getCashoutRate(conversion: { debit?: AmountJson, credit?: AmountJson }) {
    const url = new URL(`cashout-rate`, this.baseUrl);
    if (conversion.debit) {
      url.searchParams.set("amount_debit", Amounts.stringify(conversion.debit))
    }
    if (conversion.credit) {
      url.searchParams.set("amount_credit", Amounts.stringify(conversion.credit))
    }
    const resp = await this.httpLib.fetch(url.href, {
      method: "GET",
    });
    switch (resp.status) {
      case HttpStatusCode.Ok: return opSuccess(resp, codecForCashoutConversionResponse())
      case HttpStatusCode.BadRequest: {
        const body = await resp.json()
        const details = codecForTalerErrorDetail().decode(body)
        switch (details.code) {
          case TalerErrorCode.GENERIC_PARAMETER_MISSING: return opKnownFailure("missing-params", resp);
          case TalerErrorCode.GENERIC_PARAMETER_MALFORMED: return opKnownFailure("wrong-calculation", resp);
          case TalerErrorCode.GENERIC_CURRENCY_MISMATCH: return opKnownFailure("wrong-currency", resp);
          default: return opUnknownFailure(resp, body)
        }
      }
      case HttpStatusCode.Conflict: return opKnownFailure("amount-too-small", resp);
      case HttpStatusCode.NotImplemented: return opKnownFailure("conversion-not-supported", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  /**
   * https://docs.taler.net/core/api-bank-conversion-info.html#post--conversion-rate
   * 
   */
  async updateConversionRate(auth: AccessToken, body: TalerBankConversionApi.ConversionRate) {
    const url = new URL(`conversion-rate`, this.baseUrl);
    const resp = await this.httpLib.fetch(url.href, {
      method: "POST",
      headers: {
        Authorization: makeBearerTokenAuthHeader(auth)
      },
      body
    });
    switch (resp.status) {
      case HttpStatusCode.NoContent: return opEmptySuccess()
      case HttpStatusCode.Unauthorized: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.NotImplemented: return opKnownFailure("conversion-not-supported", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

}