// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity 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 General Public License for more details.

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

export default function (rpc) {
  let _subscriptions = [];
  let _pollStatusIntervalId = null;
  let _subscriptionPromises = null;

  function getCoins () {
    return rpc.get('getcoins');
  }

  function getMarketInfo (pair) {
    return rpc.get(`marketinfo/${pair}`);
  }

  function getRpc () {
    return rpc;
  }

  function getStatus (depositAddress) {
    return rpc.get(`txStat/${depositAddress}`);
  }

  function shift (toAddress, returnAddress, pair) {
    return rpc.post('shift', {
      pair,
      returnAddress,
      withdrawal: toAddress
    });
  }

  function subscribe (depositAddress, callback) {
    if (!depositAddress || !callback) {
      return;
    }

    const index = _subscriptions.length;

    _subscriptions.push({
      callback,
      depositAddress,
      index
    });

    if (_pollStatusIntervalId === null) {
      _pollStatusIntervalId = setInterval(_pollStatus, 2000);
    }
  }

  function unsubscribe (depositAddress) {
    _subscriptions = _subscriptions.filter((sub) => sub.depositAddress !== depositAddress);

    if (_subscriptions.length === 0) {
      clearInterval(_pollStatusIntervalId);
      _pollStatusIntervalId = null;
    }

    return true;
  }

  function _getSubscriptionStatus (subscription) {
    if (!subscription) {
      return Promise.resolve();
    }

    return getStatus(subscription.depositAddress)
      .then((result) => {
        switch (result.status) {
          case 'no_deposits':
          case 'received':
            subscription.callback(null, result);
            return true;

          case 'complete':
            subscription.callback(null, result);
            unsubscribe(subscription.depositAddress);
            return true;

          case 'failed':
            subscription.callback({
              message: status.error,
              fatal: true
            });
            unsubscribe(subscription.depositAddress);
            return true;
        }
      })
      .catch(() => {
        return true;
      });
  }

  function _pollStatus () {
    _subscriptionPromises = Promise.all(_subscriptions.map(_getSubscriptionStatus));
  }

  function _getSubscriptions () {
    return _subscriptions;
  }

  function _getSubscriptionPromises () {
    return _subscriptionPromises;
  }

  function _isPolling () {
    return _pollStatusIntervalId !== null;
  }

  return {
    _getSubscriptions,
    _getSubscriptionPromises,
    _isPolling,
    getCoins,
    getMarketInfo,
    getRpc,
    getStatus,
    shift,
    subscribe,
    unsubscribe
  };
}