..
  This file is part of GNU TALER.

  Copyright (C) 2014-2023 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free Software
  Foundation; either version 2.1, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>

.. target audience: developer, core developer

.. _corebank-api:

====================
Taler Core Bank API
====================

.. contents:: Table of Contents

Introduction
------------

The Libeufin bank provides a minimal core banking system.  In addition to that,
it provides features for local/regional currencies.

Authentication
--------------

Some requests require the client to authenticate via HTTP Basic auth (RFC 7617)
or using a bearer token which can be obtained or refreshed from the
``/accounts/$USERNAME/token`` endpoint.
When using Basic authentication, the user-id must be the bank
username, and the password the password for the corresponding user.

Another way to obtain a login token is by manually configuring it for certain
endpoints.  For example, the exchange could give an auditor read-only access to
the taler-wire-gateway facade via such a manually configured access token.

The ``admin`` user is a special, hard-coded username. Some requests require the
client to authenticate as the admin.

.. http:post:: /accounts/$USERNAME/token

   See :ref:`DD 48 token endpoint <dd48-token>`.


Bank Web UI
-----------

The web UI for the bank is typically served under ``/``.

Config
------

.. http:get:: /config

  **Response:**

  :http:statuscode:`200 OK`: 
    Response is a `Config`.

  **Details:**

  .. ts:def:: Config

    interface Config {
      // Name of this API, always "taler-corebank".
      name: string;

      // API version in the form $n:$n:$n
      version: string;

      // If 'true' the server provides local currency conversion support
      // If 'false' some parts of the API are not supported and return 501
      allow_conversion: boolean;

      // If 'true' anyone can register 
      // If 'false' only the admin can
      allow_registrations: boolean;

      // If 'true' account can delete themselves
      // If 'false' only the admin can delete accounts
      allow_deletions: boolean;
      
      // Currency used by this bank.
      currency: string;

      // How the bank SPA should render this currency.
      currency_specification: CurrencySpecification;
    }


Account Management
------------------

.. _bank-account-register:

.. http:post:: /accounts

  Create a new bank account.  Depending on the configuration,
  the account creation is self-serve, or only restricted to
  the administrators.

  **Request:**

  .. ts:def:: RegisterAccountRequest

    interface RegisterAccountRequest {
      // Username
      username: string;

      // Password.
      password: string;

      // Legal name of the account owner
      name: string;

      // Defaults to false.
      is_public?: boolean;

      // Is this a taler exchange account?
      // If true:
      // - incoming transactions to the account that do not
      //   have a valid reserve public key are automatically
      // - the account provides the taler-wire-gateway-api endpoints
      // Defaults to false.
      is_taler_exchange?: boolean;

      // Addresses where to send the TAN for transactions.
      // Currently only used for cashouts.
      // If missing, cashouts will fail.
      // In the future, might be used for other transactions
      // as well.
      challenge_contact_data?: ChallengeContactData;

      // 'payto' address of a fiat bank account.
      // Payments will be sent to this bank account
      // when the user wants to convert the regional currency
      // back to fiat currency outside bank.
      cashout_payto_uri?: string;

      // Internal payto URI of this bank account.
      // Used mostly for testing.
      internal_payto_uri?: string;
    }

  .. ts:def:: ChallengeContactData

    interface ChallengeContactData {

      // E-Mail address
      email?: EmailAddress;

      // Phone number.
      phone?: PhoneNumber;
    }


  **Response:**

  :http:statuscode:`201 Created`:
    The account was successfully created.
  :http:statuscode:`400 Bad request`:
    Input data was invalid.  For example, the client specified a invalid
    phone number or e-mail address.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_REGISTER_USERNAME_REUSE`` : username already used.
    * ``TALER_EC_BANK_REGISTER_PAYTO_URI_REUSE`` : payto URI already used.
    * ``TALER_EC_BANK_UNALLOWED_DEBIT`` : admin account does not have sufficient funds to grant bonus.
    * ``TALER_EC_BANK_RESERVED_USERNAME_CONFLICT`` : a reserved username was attempted, like ``admin`` or ``bank``

.. _delete-account:

.. http:delete:: /accounts/$USERNAME

  Delete the account whose username is ``$USERNAME``.  The deletion
  succeeds only if the balance is *zero*.  Typically only available to
  the administrator, but can be configured to allow ordinary users too.

  **Response:**

  :http:statuscode:`204 No content`:
    The account was successfully deleted.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_RESERVED_USERNAME_CONFLICT`` : a reserved username was attempted, like ``admin`` or ``bank``.
    * ``TALER_EC_BANK_ACCOUNT_BALANCE_NOT_ZERO``: the account balance was not zero.

.. _account-reconfig:

.. http:patch:: /accounts/$USERNAME

  Allows reconfiguring the account data of ``$USERNAME``.

  **Request:**

  .. ts:def:: AccountReconfiguration

    interface AccountReconfiguration {
      // Addresses where to send the TAN for transactions.
      // Currently only used for cashouts.
      // If missing, cashouts will fail.
      // In the future, might be used for other transactions
      // as well.
      challenge_contact_data?: ChallengeContactData;

      // 'payto' address of a fiat bank account.
      // Payments will be sent to this bank account
      // when the user wants to convert the regional currency
      // back to fiat currency outside bank.
      cashout_payto_uri?: string;

      // If present, change the legal name associated with $username.
      // Only admin can change this property.
      name?: string;

      // If present, change the is_taler_exchange configuration.
      // See `RegisterAccountRequest`
      is_taler_exchange?: boolean;

      // If present, change the max debit allowed for this user
      // Only admin can change this property.
      debit_threshold?: Amount
    }

  **Response:**

  :http:statuscode:`204 No content`:
    Operation successful.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_PATCH_ADMIN_EXCHANGE``: an admin user has tried to become an exchange.
    * ``TALER_EC_BANK_NON_ADMIN_PATCH_LEGAL_NAME`` : a non-admin user has tried to change their legal name.
    * ``TALER_EC_BANK_NON_ADMIN_PATCH_DEBT_LIMIT``: a non-admin user has tried to change their debt limit.


.. _account-password-reconfig:

.. http:patch:: /accounts/$USERNAME/auth

  Allows changing the account's password.
  

  **Request:**

  .. ts:def:: AccountPasswordChange

    interface AccountPasswordChange {
      // Old password. If present it need to match the current
      // password before updating.
      old_password?: string;
      // New password.
      new_password: string;
    }

  **Response:**

  :http:statuscode:`204 No content`:
    Operation successful.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_NON_ADMIN_PATCH_MISSING_OLD_PASSWORD``: a non-admin user has tried to change their password whihout providing the current one.
    * ``TALER_EC_BANK_PATCH_BAD_OLD_PASSWORD`` : provided old password does not match current password.

.. _account-list:

.. http:get:: /public-accounts

  Show those accounts whose histories are publicly visible.  For example,
  accounts from donation receivers.  As such, this request is unauthenticated.
  

  **Request:**

  :query delta: *Optional.*
    Takes value of the form ``N (-N)``, so that at most ``N`` values strictly older (younger) than ``start`` are returned.  Defaults to ``-20`` to return the last 20 entries.
  :query start: *Optional.* 
    Row number threshold, see ``delta`` for its interpretation. Defaults to smallest or biggest row id possible according to ``delta`` sign.
  :query filter_name: *Optional.*
    Pattern to filter on the account legal name.  Given
    the filter 'foo', all the results will **contain**
    'foo' in their legal name.  Without this option,
    all the existing accounts are returned.

  **Response:**

  :http:statuscode:`200 OK`:
    Response is a `PublicAccountsResponse`.
  :http:statuscode:`204 No content`:
    No public account.

  **Details:**

  .. ts:def:: PublicAccountsResponse

    interface PublicAccountsResponse {
      public_accounts: PublicAccount[];
    }

  .. ts:def:: PublicAccount

    interface PublicAccount {
      payto_uri: string;

      balance: Balance;

      // The account name (=username) of the
      // bank account.
      account_name: string;
    }

.. http:get:: /accounts

  Obtains a list of the accounts registered at the bank.
  It returns only the information that this API handles, without
  any balance or transactions list.
  This request is only available to the administrator.

  **Request:**

  :query delta: *Optional.*
    Takes value of the form ``N (-N)``, so that at most ``N`` values strictly older (younger) than ``start`` are returned.  Defaults to ``-20`` to return the last 20 entries.
  :query start: *Optional.* 
    Row number threshold, see ``delta`` for its interpretation. Defaults to smallest or biggest row id possible according to ``delta`` sign.
  :query filter_name: *Optional.*
    Pattern to filter on the account legal name.  Given
    the filter 'foo', all the results will **contain**
    'foo' in their legal name.  Without this option,
    all the existing accounts are returned.

  **Response:**

  :http:statuscode:`200 OK`:
    At least one account was found.
    The server responds with a `ListBankAccountsResponse` object.
  :http:statuscode:`204 No Content`:
    No accounts were found for the given request.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.

  **Details:**

  .. ts:def:: ListBankAccountsResponse

    interfaces ListBankAccountsResponse {
      accounts: AccountMinimalData[];
    }

  .. ts:def:: Balance

    interface Balance {
      amount: Amount;
      credit_debit_indicator: "credit" | "debit";
    }

  .. ts:def:: AccountMinimalData

    interface AccountMinimalData {
      // Username
      username: string;

      // Legal name of the account owner.
      name: string;

      // current balance of the account
      balance: Balance;

      // Number indicating the max debit allowed for the requesting user.
      debit_threshold: Amount;
    }

.. _bank-account-info:

.. http:get:: /accounts/$USERNAME

  Obtains information relative to the account owned by
  ``$USERNAME``.  The request is available to the administrator
  and ``$USERNAME`` itself.

  **Response:**

  :http:statuscode:`200 OK`:
    The bank responds with an `AccountData` object.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.

  **Details:**

  .. ts:def:: AccountData

    interface AccountData {
      // Legal name of the account owner.
      name: string;

      // Available balance on the account.
      balance: Balance;

      // payto://-URI of the account.
      payto_uri: string;

      // Number indicating the max debit allowed for the requesting user.
      debit_threshold: Amount;

      contact_data?: ChallengeContactData;

      // 'payto' address pointing the bank account
      // where to send cashouts.  This field is optional
      // because not all the accounts are required to participate
      // in the merchants' circuit.  One example is the exchange:
      // that never cashouts.  Registering these accounts can
      // be done via the access API.
      cashout_payto_uri?: string;
    }

Transactions
------------

.. http:get:: /accounts/$USERNAME/transactions

  Retrieve a subset of transactions related to $USERNAME.

  The list of returned transactions is determined by a row ID *starting point*
  and a signed non-zero integer *delta*:

  * If *delta* is positive, return a list of up to *delta* transactions (all matching
    the filter criteria) strictly **after** the starting point.  The transactions are sorted
    in **ascending** order of the row ID.
  * If *delta* is negative, return a list of up to *-delta* transactions (all matching
    the filter criteria) strictly **before** the starting point.  The transactions are sorted
    in **descending** order of the row ID.

  If *starting point* is not explicitly given, it defaults to:

  * A value that is **smaller** than all other row IDs if *delta* is **positive**.
  * A value that is **larger** than all other row IDs if *delta* is **negative**.

  **Request:**

  :query delta: *Optional.*
    Takes value of the form ``N (-N)``, so that at most ``N`` values strictly older (younger) than ``start`` are returned.  Defaults to ``-20`` to return the last 20 entries.
  :query start: *Optional.* 
    Row number threshold, see ``delta`` for its interpretation. Defaults to smallest or biggest row id possible according to ``delta`` sign.
  :query long_poll_ms: Optional number to express how many milliseconds the server
    should wait for at least one result to be shown.  If not given, the server
    responds immediately, regardless of the result.

  **Response:**

  :http:statuscode:`200 OK`:
    The bank responds with an `BankAccountTransactionsResponse` object.
  :http:statuscode:`204 No content`:
    No transaction found.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.

  **Details:**

  .. ts:def:: BankAccountTransactionsResponse

    interface BankAccountTransactionsResponse {
      transactions: BankAccountTransactionInfo[];
    }

.. http:get:: /accounts/$USERNAME/transactions/$TRANSACTION_ID

  Retrieve the transaction whose identifier is ``TRANSACTION_ID``.

  **Response:**

  :http:statuscode:`200 OK`:
    The bank responds with an `BankAccountTransactionInfo` object.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials or missing rights.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.

  **Details:**

  .. ts:def:: BankAccountTransactionInfo

    interface BankAccountTransactionInfo {
      creditor_payto_uri: string;
      debtor_payto_uri: string;

      amount: Amount;
      direction: "debit" | "credit";

      subject: string;

      // Transaction unique ID.  Matches
      // $TRANSACTION_ID from the URI.
      row_id: Integer;
      date: Timestamp;
    }

.. http:post:: /accounts/$USERNAME/transactions

  Create a new transaction where the bank account with the label ``USERNAME`` is **debited**.

  **Request:**

  .. ts:def:: CreateTransactionRequest

    interface CreateTransactionRequest {
      // Address in the Payto format of the wire transfer receiver.
      // It needs at least the 'message' query string parameter.
      payto_uri: string;

      // Transaction amount (in the $currency:x.y format), optional.
      // However, when not given, its value must occupy the 'amount'
      // query string parameter of the 'payto' field.  In case it
      // is given in both places, the payto_uri's takes the precedence.
      amount: string;
    }

  **Response:**

  :http:statuscode:`200 Ok`:
    The bank responds with an `CreateTransactionResponse` object.
  :http:statuscode:`400 Bad Request`:
    The request was invalid or the payto://-URI used unacceptable features.
  :http:statuscode:`401 Unauthorized`:
    Invalid credentials.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_SAME_ACCOUNT`` : creditor account is the same than ``USERNAME``.
    * ``TALER_EC_BANK_UNKNOWN_CREDITOR`` : creditor account was not found.
    * ``TALER_EC_BANK_UNALLOWED_DEBIT`` : the account does not have sufficient funds.

  **Details:**

  .. ts:def:: CreateTransactionResponse

    interface CreateTransactionResponse {
      // ID identifying the transaction being created
      row_id: Integer;
    }

Taler Withdrawals
-----------------

.. http:post:: /accounts/$USERNAME/withdrawals

  Create a withdrawal operation, resulting in a ``taler://withdraw`` URI.

  **Request:**

  .. ts:def:: BankAccountCreateWithdrawalRequest

    interface BankAccountCreateWithdrawalRequest {
      // Amount to withdraw.
      amount: Amount;
    }

  **Response:**

  :http:statuscode:`200 Ok`:
    The bank responds with an `BankAccountCreateWithdrawalResponse` object.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`409 Conflict`:
    The account does not have sufficient funds.

  **Details:**

  .. ts:def:: BankAccountCreateWithdrawalResponse

    interface BankAccountCreateWithdrawalResponse {
      // ID of the withdrawal, can be used to view/modify the withdrawal operation.
      // This ID will be globally unique and grant control over the operation to
      // abort or confirm it.
      withdrawal_id: string;

      // URI that can be passed to the wallet to initiate the withdrawal.
      taler_withdraw_uri: string;
    }

.. http:post:: /withdrawals/$WITHDRAWAL_ID/abort

  Aborts ``WITHDRAWAL_ID`` operation.  Has no effect on an already aborted
  operation.  Does not require further authentication as knowledge
  of the withdrawal ID serves as an authenticator.

  **Response:**

  :http:statuscode:`204 No content`: 
    The withdrawal operation has been aborted.
  :http:statuscode:`404 Not found`:
    The withdrawal operation was not found.
  :http:statuscode:`409 Conflict`: 
    The withdrawal operation has been confirmed previously and can't be aborted.

.. http:post:: /withdrawals/$WITHDRAWAL_ID/confirm

  Confirms ``WITHDRAWAL_ID`` operation.  Has no effect on an already confirmed
  withdrawal operation.  This call is responsible for wiring the funds to the
  exchange.  Does not require further authentication as knowledge of the
  withdrawal ID serves as an authenticator.

  **Response:**

  :http:statuscode:`204 No content`:
    The withdrawal operation has been confirmed.
  :http:statuscode:`404 Not found`:
    The operation was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_CONFIRM_ABORT_CONFLICT`` : the withdrawal has been aborted previously and can't be confirmed.
    * ``TALER_EC_BANK_CONFIRM_INCOMPLETE`` : the withdraw operation cannot be confirmed because no exchange and reserve public key selection happened before.
    * ``TALER_EC_BANK_UNALLOWED_DEBIT`` : the account does not have sufficient funds.

.. http:get:: /withdrawals/$WITHDRAWAL_ID

  Query the status of a withdrawal operation. Does not require further
  authentication as knowledge of the withdrawal ID serves as an authenticator.

  **Response:**

  :http:statuscode:`200 Ok`:
    The bank responds with an `BankAccountGetWithdrawalResponse` object.
  :http:statuscode:`404 Not found`:
    The operation was not found.

  **Details:**

  .. ts:def:: BankAccountGetWithdrawalResponse

    interface BankAccountGetWithdrawalResponse {
      // Amount that will be withdrawn with this withdrawal operation.
      amount: Amount;

      // Was the withdrawal aborted?
      aborted: boolean;

      // Has the withdrawal been confirmed by the bank?
      // The wire transfer for a withdrawal is only executed once
      // both ``confirmation_done`` is ``true`` and ``selection_done`` is ``true``.
      confirmation_done: boolean;

      // Did the wallet select reserve details?
      selection_done: boolean;

      // Reserve public key selected by the exchange,
      // only non-null if ``selection_done`` is ``true``.
      selected_reserve_pub: string | null;

      // Exchange account selected by the wallet, or by the bank
      // (with the default exchange) in case the wallet did not provide one
      // through the Integration API.
      selected_exchange_account: string | null;
    }

Cashouts
--------

.. _account-cashout:

.. http:post:: /accounts/$USERNAME/cashouts

  Initiates a conversion to fiat currency.  The fiat
  bank account to be
  credited is the one specified at registration time via the
  *cashout_payto_uri* parameter.  The regional bank account
  is specified via ``$USERNAME``.
  The bank sends a TAN to the customer to let them confirm the
  operation.  The request is only available to ordinary users, not
  to the administrator.

  The same request can be posted several times to trigger TAN retransmission. 

  .. note::

    Consult the `cashout rates call <cashout-rates_>`_ to learn
    about any applicable fee or exchange rate.


  **Request:**

  .. ts:def:: TanChannel

    enum TanChannel {
      SMS = "sms",
      EMAIL = "email"
    }

  .. ts:def:: CashoutRequest

    interface CashoutRequest {
      // Nonce to make the request idempotent.  Requests with the same
      // ``request_uid`` that differ in any of the other fields
      // are rejected.
      request_uid: ShortHashCode;

      // Optional subject to associate to the
      // cashout operation.  This data will appear
      // as the incoming wire transfer subject in
      // the user's fiat bank account.
      subject?: string;

      // That is the plain amount that the user specified
      // to cashout.  Its $currency is the (regional) currency of the
      // bank instance.
      amount_debit: Amount;

      // That is the amount that will effectively be
      // transferred by the bank to the user's fiat bank
      // account.
      // It is expressed in the fiat currency and
      // is calculated after the cashout fee and the
      // exchange rate.  See the /cashout-rate call.
      // The client needs to calculate this amount
      // correctly based on the amount_debit and the cashout rate,
      // otherwise the request will fail.
      amount_credit: Amount;

      // Which channel the TAN should be sent to.  If
      // this field is missing, it defaults to SMS.
      // The default choice prefers to change the communication
      // channel respect to the one used to issue this request.
      tan_channel?: TanChannel;
    }

  **Response:**

  :http:statuscode:`200 Accepted`:
    The cashout request was correctly created and
    the TAN authentication now is pending.
    This returns the `CashoutPending` response.
  :http:statuscode:`404 Not found`:
    The account pointed by ``$USERNAME`` was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_TRANSFER_REQUEST_UID_REUSED``: an operation with the same ``request_uid`` but different details has been submitted before.
    * ``TALER_EC_BANK_BAD_CONVERSION`` : exchange rate was calculated incorrectly by the client.
    * ``TALER_EC_BANK_MISSING_TAN_INFO`` : the user did not share any contact data where to send the TAN via ``tan_channel``.
    * ``TALER_EC_BANK_UNALLOWED_DEBIT`` : the account does not have sufficient funds.
  :http:statuscode:`501 Not Implemented`:
    * ``TALER_EC_BANK_TAN_CHANNEL_NOT_SUPPORTED``: the chosen ``tan_channel`` is not currently supported.
    * This server does not support conversion, client should check config response.
  :http:statuscode:`502 Bad Gateway`:
    * ``TALER_EC_BANK_TAN_CHANNEL_SCRIPT_FAILED``: TAN transmition via ``tan_channel`` failed.

  **Details:**

  .. ts:def:: CashoutPending

    interface CashoutPending {
      // ID identifying the operation being created
      // and now waiting for the TAN confirmation.
      cashout_id: Integer;
    }


.. _cashout-abort:

.. http:post:: /accounts/$USERNAME/cashouts/$CASHOUT_ID/abort

  Aborts ``CASHOUT_ID`` operation. Has no effect on an already aborted
  operation.

  **Response:**

  :http:statuscode:`204 No content`:
    The cashout operation has been aborted.
  :http:statuscode:`404 Not found`:
    The cashout operation was not found.
  :http:statuscode:`409 Conflict`:
    The cashout operation has been confirmed previously and can't be aborted.
  :http:statuscode:`501 Not implemented`:
    This server does not support conversion, client should check config response.

.. _cashout-confirm:

.. http:post:: /accounts/$USERNAME/cashouts/$CASHOUT_ID/confirm

  Confirms ``CASHOUT_ID`` operation by providing its
  TAN. Has no effect on an already confirmed
  cashout operation. This call is responsible for wiring the funds to the
  user's fiat bank account.

  **Request:**

  .. ts:def:: CashoutConfirm

    interface CashoutConfirm {
      // the TAN that confirms $CASHOUT_ID.
      tan: string;
    }

  **Response:**

  :http:statuscode:`204 No content`:
    The cashout operation has been confirmed.
  :http:statuscode:`404 Not found`:
    The operation was not found.
  :http:statuscode:`409 Conflict`:
    * ``TALER_EC_BANK_CONFIRM_ABORT_CONFLICT`` : the cashout has been aborted previously and can't be confirmed.
    * ``TALER_EC_BANK_CONFIRM_INCOMPLETE`` : the user did not share any cashout payto to uri where to wire funds.
    * ``TALER_EC_BANK_UNALLOWED_DEBIT`` : the account does not have sufficient funds.
    * ``TALER_EC_BANK_BAD_CONVERSION`` : exchange rate has changed since operation creation.
    * ``TALER_EC_BANK_TAN_CHALLENGE_FAILED`` : wrong or expired TAN.
  :http:statuscode:`429 Too many requests`:
    Too many failed confirmation attempts, a new TAN must be requested.
  :http:statuscode:`501 Not implemented`:
    This server does not support conversion, client should check config response.


.. _circuit-cashout-details:

.. http:get:: /accounts/$USERNAME/cashouts/$CASHOUT_ID

  Returns information about the status of the ``$CASHOUT_ID`` operation.
  The request is available to the administrator and the account owner.

  **Response:**

  :http:statuscode:`200 OK`:
    Response is a `CashoutStatusResponse`.
  :http:statuscode:`404 Not found`:
    The cashout operation was not found.
  :http:statuscode:`501 Not implemented`:
    This server does not support conversion, client should check config response.

  **Details:**

  .. ts:def:: CashoutStatusResponse

    interface CashoutStatusResponse {
      status: "pending" | "aborted" | "confirmed";

      // Amount debited to the regional bank account.
      amount_debit: Amount;

      // Amount credited to the fiat bank account.
      amount_credit: Amount;

      // Transaction subject.
      subject: string;

      // Time when the cashout was created.
      creation_time: Timestamp;

      // Time when the cashout was confirmed via its TAN.
      // Missing when the operation wasn't confirmed yet.
      confirmation_time?: Timestamp;
    }

.. _circuit-cashouts:

.. http:get:: /accounts/$USERNAME/cashouts

  Returns the list of all the (pending and confirmed) cash-out operations
  for an account.

  **Request:**

  :query delta: *Optional.*
    Takes value of the form ``N (-N)``, so that at most ``N`` values strictly older (younger) than ``start`` are returned.  Defaults to ``-20`` to return the last 20 entries.
  :query start: *Optional.* 
    Row number threshold, see ``delta`` for its interpretation. Defaults to smallest or biggest row id possible according to ``delta`` sign.

  **Response:**

  :http:statuscode:`200 OK`:
    Response is a `Cashouts`.
  :http:statuscode:`204 No Content`:
    No cash-out operations were found.
  :http:statuscode:`501 Not implemented`:
    This server does not support conversion, client should check config response.

  **Details:**

  .. ts:def:: Cashouts

    interface Cashouts {
      // Every string represents a cash-out operation ID.
      cashouts: CashoutInfo[];
    }

  .. ts:def:: CashoutInfo

    interface CashoutInfo {
      cashout_id: Integer;
      status: "pending" | "aborted" | "confirmed";
    }

.. http:get:: /cashouts

  Returns the list of all the (pending and confirmed) cash-out operations
  for **all** accounts.

  Typically can only be used by the administrators.

  **Request:**

  :query delta: *Optional.*
    Takes value of the form ``N (-N)``, so that at most ``N`` values strictly older (younger) than ``start`` are returned.  Defaults to ``-20`` to return the last 20 entries.
  :query start: *Optional.* 
    Row number threshold, see ``delta`` for its interpretation. Defaults to smallest or biggest row id possible according to ``delta`` sign.

  .. note::

    We might want to add a filter in the future to only
    query pending cashout operations.

  **Response:**

  :http:statuscode:`200 OK`:
    Response is a `GlobalCashouts`.
  :http:statuscode:`204 No Content`:
    No cash-out operations were found.
  :http:statuscode:`501 Not implemented`:
    This server does not support conversion, client should check config response.

  **Details:**

  .. ts:def:: GlobalCashouts

    interface GlobalCashouts {
      cashouts: GlobalCashoutInfo[];
    }

  .. ts:def:: GlobalCashoutInfo

    interface GlobalCashoutInfo {
      cashout_id: Integer;
      username: string;
      status: "pending" | "aborted" | "confirmed";
    }

.. _cashout-rates:


Monitor
-------

.. http:get:: /monitor

  When the bank provides conversion between the local currency and an
  external one, this call lets the bank administrator monitor the cashin
  and cashout operations that were made from and to the external currency.
  It shows as well figures related to internal payments made by a Taler
  exchange component to internal bank accounts. Timeframes are in UTC.

  **Request:**

  :query timeframe: *Optional*.
    This parameter admits one of the following values. Defaults to 'hour'.

    * hour
    * day
    * month
    * year

  :query which: *Optional*.
    This parameter points at a particular element of the *timeframe* parameter.
    Following are the admitted values for each one.
    Default to the last snapshot taken of the *timeframe* parameter.

    * hour: from 00 to 23
    * day: from 1 to the last day of the current month.
    * month: from 1 to 12
    * year: Gregorian year in the YYYY format.

  **Response:**

  :http:statuscode:`200 OK`: 
    The bank responds with `MonitorResponse`.
  :http:statuscode:`400 Bad Request`:
    This error may indicate that the *which* parameter is not appropriate for the selected *timeframe*.  For example, timeframe=month and which=20 would result in this error.

  **Details:**

  .. note::

    API consumers may combine the values in the response with other
    factors to serve different views to their users.

  .. ts:def:: MonitorResponse
    
    // Union discriminated by the "type" field.
    type MonitorResponse =
      | MonitorNoConversion
      | MonitorWithConversion;

  .. ts:def:: MonitorNoConversion

    // Monitoring stats when conversion is not supported
    interface MonitorNoConversion {
      type: "no-conversions";

      // How many payments were made to a Taler exchange by another
      // bank account.
      talerInCount: Integer;

      // Overall volume that has been paid to a Taler 
      // exchange by another bank account.
      talerInVolume: Amount;

      // How many payments were made by a Taler exchange to another
      // bank account.
      talerOutCount: Integer;

      // Overall volume that has been paid by a Taler 
      // exchange to another bank account.
      talerOutVolume: Amount;
    }

  .. ts:def:: MonitorWithConversion

    // Monitoring stats when conversion is supported
    interface MonitorWithConversion {
      type: "with-conversions";

      // How many cashin operations were confirmed by a 
      // wallet owner. Note: wallet owners
      // are NOT required to be customers of the libeufin-bank.
      cashinCount: Integer;

      // Overall regional currency that has been paid by the regional admin account
      // to regional bank accounts to fulfill all the confirmed cashin operations.
      cashinRegionalVolume: Amount;

      // Overall fiat currency that has been paid to the fiat admin account
      // by fiat bank accounts to fulfill all the confirmed cashin operations.
      cashinFiatVolume: Amount;

      // How many cashout operations were confirmed.
      cashoutCount: Integer;

      // Overall regional currency that has been paid to the regional admin account
      // by fiat bank accounts to fulfill all the confirmed cashout operations.
      cashoutRegionalVolume: Amount;

      // Overall fiat currency that has been paid by the fiat admin account
      // to fiat bank accounts to fulfill all the confirmed cashout operations.
      cashoutFiatVolume: Amount;

      // How many payments were made to a Taler exchange by another
      // bank account.
      talerInCount: Integer;

      // Overall volume that has been paid to a Taler 
      // exchange by another bank account.
      talerInVolume: Amount;

      // How many payments were made by a Taler exchange to another
      // bank account.
      talerOutCount: Integer;

      // Overall volume that has been paid by a Taler 
      // exchange to another bank account.
      talerOutVolume: Amount;
    }


Taler Bank Integration API
--------------------------

.. http:any:: /taler-integration/*

  All endpoints under this prefix are specified by the.
  :doc:`GNU Taler bank integration API </core/api-bank-integration>`.
  This API handles the communication with Taler wallets.

Taler Wire Gateway API
----------------------

.. http:any:: /accounts/$USERNAME/taler-wire-gateway/*

   All endpoints under this prefix are specified
   by the :doc:`GNU Taler wire gateway API </core/api-bank-wire>`.

   The endpoints are only available for accounts configured with ``is_taler_exchange=true``.

Taler Revenue API
-----------------

.. http:any:: /accounts/$USERNAME/taler-revenue/*

   All endpoints under this prefix are specified
   by the :doc:`GNU Taler Revenue API </core/api-bank-revenue>`.

Taler Conversion Info API
-------------------------

.. http:any:: /conversion-info/*

   All endpoints under this prefix are specified
   by the :doc:`GNU Taler Conversion Info API </core/api-bank-conversion-info>`.

EBICS Host
----------

The Taler bank can be configured to serve bank account transactions and allow
payment initiations via the EBICS protocol.

This is an optional feature, not all implementations of the API support it.

.. http:post:: /ebicshost

   EBICS base URL.  This URL allows clients to make EBICS requests to one of
   the configured EBICS hosts.