const http = require('http');
const url = require('url');
const util = require('util');
const ProjectionCommandFailedError = require('../errors/projectionCommandFailedError');

const HTTP_OK = 200;
const HTTP_CREATED = 201;

function safeParseJson(json) {
  try {
    return JSON.parse(json);
  } catch(e) {
    return null;
  }
}

function ProjectionsClient(log, operationTimeout) {
  this._log = log;
  this._operationTimeout = operationTimeout;
}

ProjectionsClient.prototype.enable = function(httpEndPoint, name, userCredentials) {
  return this.sendPost(httpEndPoint + '/projection/' + name + '/command/enable', '', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.disable = function(httpEndPoint, name, userCredentials) {
  return this.sendPost(httpEndPoint + '/projection/' + name + '/command/disable', '', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.abort = function(httpEndPoint, name, userCredentials) {
  return this.sendPost(httpEndPoint + '/projection/' + name + '/command/abort', '', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.createOneTime = function(httpEndPoint, query, userCredentials) {
  return this.sendPost(httpEndPoint + '/projections/onetime?type=JS', query, userCredentials, HTTP_CREATED);
};

ProjectionsClient.prototype.createTransient = function(httpEndPoint, name, query, userCredentials) {
  return this.sendPost(httpEndPoint + '/projections/transient?name=' + name + '&type=JS', query, userCredentials, HTTP_CREATED);
};

ProjectionsClient.prototype.createContinuous = function(httpEndPoint, name, query, trackEmittedStreams, userCredentials) {
  return this.sendPost(httpEndPoint + '/projections/continuous?name=' + name + '&type=JS&emit=1&trackemittedstreams=' + trackEmittedStreams, query, userCredentials, HTTP_CREATED);
};

ProjectionsClient.prototype.listAll = function(httpEndPoint, userCredentials) {
  return this.sendGet(httpEndPoint + '/projections/any', userCredentials, HTTP_OK)
    .then(function (json) {
      var r = safeParseJson(json);
      if (r && r.projections) return r.projections;
      return null;
    });
};

ProjectionsClient.prototype.listOneTime = function(httpEndPoint, userCredentials) {
  return this.sendGet(httpEndPoint + '/projections/onetime', userCredentials, HTTP_OK)
    .then(function (json) {
      var r = safeParseJson(json);
      if (r && r.projections) return r.projections;
      return null;
    });
};

ProjectionsClient.prototype.listContinuous = function(httpEndPoint, userCredentials) {
  return this.sendGet(httpEndPoint + '/projections/continuous', userCredentials, HTTP_OK)
    .then(function (json) {
      var r = safeParseJson(json);
      if (r && r.projections) return r.projections;
      return null;
    });
};

ProjectionsClient.prototype.getStatus = function(httpEndPoint, name, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name, userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getState = function(httpEndPoint, name, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/state', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getPartitionState = function(httpEndPoint, name, partitionId, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/state?partition=' + partitionId, userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getResult = function(httpEndPoint, name, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/result', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getPartitionResult = function(httpEndPoint, name, partitionId, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/result?partition=' + partitionId, userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getStatistics = function(httpEndPoint, name, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/statistics', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.getQuery = function(httpEndPoint, name, userCredentials) {
  return this.sendGet(httpEndPoint + '/projection/' + name + '/query', userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.updateQuery = function(httpEndPoint, name, query, userCredentials) {
  return this.sendPut(httpEndPoint + '/projection/' + name + '/query?type=JS', query, userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.delete = function(httpEndPoint, name, deleteEmittedStreams, deleteStateStream, deleteCheckpointStream, userCredentials) {
  const stateStream = (deleteStateStream === undefined) ? false : deleteStateStream;
  const checkpointStream = (deleteCheckpointStream === undefined) ? false : deleteCheckpointStream;
  return this.sendDelete(httpEndPoint + '/projection/' + name + '?deleteStateStream=' + stateStream + '&deleteCheckpointStream' + checkpointStream + '&deleteEmittedStreams=' + deleteEmittedStreams, userCredentials, HTTP_OK);
};

ProjectionsClient.prototype.request = function(method, _url, data, userCredentials, expectedCode) {
  const options = url.parse(_url);
  options.method = method;
  if (userCredentials) {
    options.auth = [userCredentials.username, userCredentials.password].join(':');
  }
  var self = this;
  return new Promise(function (resolve, reject) {
    const timeout = setTimeout(function () {
      reject(new Error(util.format('Request timed out for %s on %s', method, _url)))
    }, self._operationTimeout);
    const req = http.request(options, function (res) {
      const hasExpectedCode = res.statusCode === expectedCode;
      var result = '';
      res.setEncoding('utf8');
      res.on('data', function (chunk) {
        result += chunk;
      });
      res.on('end', function () {
        if (hasExpectedCode) {
          clearTimeout(timeout);
          resolve(result);
        } else {
          clearTimeout(timeout);
          reject(new ProjectionCommandFailedError(
            res.statusCode,
            util.format('Server returned %d (%s) for %s on %s', res.statusCode, res.statusMessage, method, _url)
          ));
        }
      });
    });
    req.on('error', reject);
    if (data) {
      req.setHeader('Content-Length', data.length);
      req.setHeader('Content-Type', 'application/json');
      req.write(data);
    }
    req.end();
  });
};

function voidResult() {}

ProjectionsClient.prototype.sendGet = function(_url, userCredentials, expectedCode) {
  return this.request('GET', _url, null, userCredentials, expectedCode);
};

ProjectionsClient.prototype.sendPost = function(_url, data, userCredentials, expectedCode) {
  return this.request('POST', _url, data, userCredentials, expectedCode)
    .then(voidResult);
};

ProjectionsClient.prototype.sendPut = function(_url, data, userCredentials, expectedCode) {
  return this.request('PUT', _url, data, userCredentials, expectedCode)
    .then(voidResult);
};

ProjectionsClient.prototype.sendDelete = function(_url, data, userCredentials, expectedCode) {
  return this.request('DELETE', _url, data, userCredentials, expectedCode)
    .then(voidResult);
};

module.exports = ProjectionsClient;