'use strict';

var _ = require('lodash');
var RSVP = require('rsvp');

var MAX_POLL_RETRIES = 2;

function pollOperation(op, pollFunction, interval, pollFailCount) {
  pollFailCount = pollFailCount || 0;
  return new RSVP.Promise(function(resolve, reject) {
    function poll() {
      pollFunction(op).then(function(result) {
        if (result.done) {
          resolve(result);
        } else {
          setTimeout(poll, interval);
        }
      }).catch(function() {
        if (pollFailCount < MAX_POLL_RETRIES) {
          pollFailCount += 1;
          setTimeout(poll, interval * 2);
        } else {
          reject('Failed to get status of operation.');
        }
      });
    }
    poll();
  });
}

function pollAndRetryOperations(operations, pollFunction, interval, printSuccess, printFail, retryCondition) {
  // This function assumes that a Google.LongRunning operation is being polled
  return RSVP.all(_.map(operations, function(op) {
    return pollOperation(op, pollFunction, interval).then(function(result) {
      if (!result.error) {
        return printSuccess(op);
      }
      if (!retryCondition(result)) {
        return printFail(op);
      }

      return op.retryFunction().then(function(retriedOperation) {
        return pollOperation(retriedOperation, pollFunction, interval);
      }).then(function(retriedResult) {
        if (retriedResult.error) {
          return printFail(op);
        }
        return printSuccess(op);
      });
    });
  }));
}

module.exports = {
  pollAndRetry: pollAndRetryOperations,
  poll: pollOperation
};