import { HttpRequestLibrary } from "../http-common.js";
import { HttpStatusCode } from "../http-status-codes.js";
import { createPlatformHttpLib } from "../http.js";
import { LibtoolVersion } from "../libtool-version.js";
import { hash } from "../nacl-fast.js";
import { FailCasesByMethod, ResultByMethod, opEmptySuccess, opFixedSuccess, opKnownFailure, opSuccess, opUnknownFailure } from "../operation.js";
import { TalerSignaturePurpose, amountToBuffer, bufferForUint32, buildSigPS, decodeCrock, eddsaSign, encodeCrock, stringToBytes, timestampRoundedToBuffer } from "../taler-crypto.js";
import { OfficerAccount, PaginationParams, SigningKey, TalerExchangeApi, codecForAmlDecisionDetails, codecForAmlRecords, codecForExchangeConfig } from "./types.js";
import { addPaginationParams } from "./utils.js";

export type TalerExchangeResultByMethod<prop extends keyof TalerExchangeHttpClient> = ResultByMethod<TalerExchangeHttpClient, prop>
export type TalerExchangeErrorsByMethod<prop extends keyof TalerExchangeHttpClient> = FailCasesByMethod<TalerExchangeHttpClient, prop>

/**
 */
export class TalerExchangeHttpClient {
  httpLib: HttpRequestLibrary;
  public readonly PROTOCOL_VERSION = "17:0:0";

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

  isCompatible(version: string): boolean {
    const compare = LibtoolVersion.compare(this.PROTOCOL_VERSION, version)
    return compare?.compatible ?? false
  }
  /**
   * https://docs.taler.net/core/api-merchant.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, codecForExchangeConfig())
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  //
  // AML operations
  //

  /**
   * https://docs.taler.net/core/api-exchange.html#get--aml-$OFFICER_PUB-decisions-$STATE
   * 
   */
  async getDecisionsByState(auth: OfficerAccount, state: TalerExchangeApi.AmlState, pagination?: PaginationParams) {
    const url = new URL(`aml/${auth.id}/decisions/${TalerExchangeApi.AmlState[state]}`, this.baseUrl);
    addPaginationParams(url, pagination)

    const resp = await this.httpLib.fetch(url.href, {
      method: "GET",
      headers: {
        "Taler-AML-Officer-Signature": buildQuerySignature(auth.signingKey)
      }
    });

    switch (resp.status) {
      case HttpStatusCode.Ok: return opSuccess(resp, codecForAmlRecords())
      case HttpStatusCode.NoContent: return opFixedSuccess({ records: [] })
      //this should be unauthorized
      case HttpStatusCode.Forbidden: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.Unauthorized: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.NotFound: return opKnownFailure("officer-not-found", resp);
      case HttpStatusCode.Conflict: return opKnownFailure("officer-disabled", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  /**
   * https://docs.taler.net/core/api-exchange.html#get--aml-$OFFICER_PUB-decision-$H_PAYTO
   * 
   */
  async getDecisionDetails(auth: OfficerAccount, account: string) {
    const url = new URL(`aml/${auth.id}/decision/${account}`, this.baseUrl);

    const resp = await this.httpLib.fetch(url.href, {
      method: "GET",
      headers: {
        "Taler-AML-Officer-Signature": buildQuerySignature(auth.signingKey)
      }
    });

    switch (resp.status) {
      case HttpStatusCode.Ok: return opSuccess(resp, codecForAmlDecisionDetails())
      case HttpStatusCode.NoContent: return opFixedSuccess({ aml_history: [], kyc_attributes: [] })
      //this should be unauthorized
      case HttpStatusCode.Forbidden: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.Unauthorized: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.NotFound: return opKnownFailure("officer-not-found", resp);
      case HttpStatusCode.Conflict: return opKnownFailure("officer-disabled", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }

  /**
   * https://docs.taler.net/core/api-exchange.html#post--aml-$OFFICER_PUB-decision
   * 
   */
  async addDecisionDetails(auth: OfficerAccount, decision: Omit<TalerExchangeApi.AmlDecision, "officer_sig">) {
    const url = new URL(`aml/${auth.id}/decision`, this.baseUrl);

    const body = buildDecisionSignature(auth.signingKey, decision)
    const resp = await this.httpLib.fetch(url.href, {
      method: "POST",
      body,
    });

    switch (resp.status) {
      case HttpStatusCode.NoContent: return opEmptySuccess()
      //FIXME: this should be unauthorized
      case HttpStatusCode.Forbidden: return opKnownFailure("unauthorized", resp);
      case HttpStatusCode.Unauthorized: return opKnownFailure("unauthorized", resp);
      //FIXME: this two need to be splitted by error code
      case HttpStatusCode.NotFound: return opKnownFailure("officer-or-account-not-found", resp);
      case HttpStatusCode.Conflict: return opKnownFailure("officer-disabled-or-recent-decision", resp);
      default: return opUnknownFailure(resp, await resp.text())
    }
  }


}

function buildQuerySignature(key: SigningKey): string {
  const sigBlob = buildSigPS(
    TalerSignaturePurpose.TALER_SIGNATURE_AML_QUERY,
  ).build();

  return encodeCrock(eddsaSign(sigBlob, key));
}

function buildDecisionSignature(
  key: SigningKey,
  decision: Omit<TalerExchangeApi.AmlDecision, "officer_sig">,
): TalerExchangeApi.AmlDecision {
  const zero = new Uint8Array(new ArrayBuffer(64))

  const sigBlob = buildSigPS(TalerSignaturePurpose.TALER_SIGNATURE_AML_DECISION)
    //TODO: new need the null terminator, also in the exchange
    .put(hash(stringToBytes(decision.justification)))//check null
    .put(timestampRoundedToBuffer(decision.decision_time))
    .put(amountToBuffer(decision.new_threshold))
    .put(decodeCrock(decision.h_payto))
    .put(zero) //kyc_requirement
    .put(bufferForUint32(decision.new_state))
    .build();

  const officer_sig = encodeCrock(eddsaSign(sigBlob, key));
  return {
    ...decision,
    officer_sig
  }
}