'use strict';

////////////////////////////////////////////////////////////////////////////////
/// @brief Replication management
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2012 triagens GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

var internal = require("internal");
var arangosh = require("@arangodb/arangosh");

var logger = {};
var applier = {};

////////////////////////////////////////////////////////////////////////////////
/// @brief return the replication logger state
////////////////////////////////////////////////////////////////////////////////

logger.state = function() {
  var db = internal.db;

  var requestResult = db._connection.GET("/_api/replication/logger-state");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief return the tick ranges that can be provided by the replication logger
////////////////////////////////////////////////////////////////////////////////

logger.tickRanges = function() {
  var db = internal.db;

  var requestResult = db._connection.GET("/_api/replication/logger-tick-ranges");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief return the first tick that can be provided by the replication logger
////////////////////////////////////////////////////////////////////////////////

logger.firstTick = function() {
  var db = internal.db;

  var requestResult = db._connection.GET("/_api/replication/logger-first-tick");
  arangosh.checkRequestResult(requestResult);

  return requestResult.firstTick;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief starts the replication applier
////////////////////////////////////////////////////////////////////////////////

applier.start = function(initialTick) {
  var db = internal.db;
  var append = "";

  if (initialTick !== undefined) {
    append = "?from=" + encodeURIComponent(initialTick);
  }

  var requestResult = db._connection.PUT("/_api/replication/applier-start" + append, "");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief stops the replication applier
////////////////////////////////////////////////////////////////////////////////

applier.stop = applier.shutdown = function() {
  var db = internal.db;

  var requestResult = db._connection.PUT("/_api/replication/applier-stop", "");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief return the replication applier state
////////////////////////////////////////////////////////////////////////////////

applier.state = function() {
  var db = internal.db;

  var requestResult = db._connection.GET("/_api/replication/applier-state");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief stop the replication applier state and "forget" all state
////////////////////////////////////////////////////////////////////////////////

applier.forget = function() {
  var db = internal.db;

  var requestResult = db._connection.DELETE("/_api/replication/applier-state");
  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief configures the replication applier
////////////////////////////////////////////////////////////////////////////////

applier.properties = function(config) {
  var db = internal.db;

  var requestResult;
  if (config === undefined) {
    requestResult = db._connection.GET("/_api/replication/applier-config");
  } else {
    requestResult = db._connection.PUT("/_api/replication/applier-config",
      JSON.stringify(config));
  }

  arangosh.checkRequestResult(requestResult);

  return requestResult;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief performs a one-time synchronization with a remote endpoint
////////////////////////////////////////////////////////////////////////////////

var sync = function(config) {
  const db = internal.db;

  const body = JSON.stringify(config || {});
  const headers = {
    "X-Arango-Async": "store"
  };
    
  const requestResult = db._connection.PUT_RAW("/_api/replication/sync", body, headers);
  arangosh.checkRequestResult(requestResult);


  if (config.async) {
    return requestResult.headers["x-arango-async-id"];
  }
   
  let count = 0;

  while (true) {
    const jobResult = db._connection.PUT(
      "/_api/job/" + requestResult.headers["x-arango-async-id"], "");
    arangosh.checkRequestResult(jobResult);

    if (jobResult.code !== 204) {
      return jobResult;
    }

    if (++count % 6 === 0) {
      internal.print("still synchronizing, please wait...");
    }

    internal.sleep(5);
  }
};

////////////////////////////////////////////////////////////////////////////////
/// @brief performs a one-time synchronization with a remote endpoint, for
/// a single collection
////////////////////////////////////////////////////////////////////////////////

var syncCollection = function(collection, config) {
  var db = internal.db;

  config = config || {};
  config.restrictType = "include";
  config.restrictCollections = [collection];
  config.includeSystem = true;

  return sync(config);
};

////////////////////////////////////////////////////////////////////////////////
/// @brief sets up the replication (all-in-one function for initial
/// synchronization and continuous replication)
////////////////////////////////////////////////////////////////////////////////

var setupReplication = function(config) {
  config = config || { };
  if (! config.hasOwnProperty('autoStart')) {
    config.autoStart = true;
  }
  if (! config.hasOwnProperty('includeSystem')) {
    config.includeSystem = true;
  }
  if (! config.hasOwnProperty('verbose')) {
    config.verbose = false;
  }

  const db = internal.db;

  const body = JSON.stringify(config);
  const headers = {
    "X-Arango-Async": "store"
  };
    
  const requestResult = db._connection.PUT_RAW("/_api/replication/make-slave", body, headers);
  arangosh.checkRequestResult(requestResult);


  if (config.async) {
    return requestResult.headers["x-arango-async-id"];
  }
   
  let count = 0;

  while (true) {
    const jobResult = db._connection.PUT(
      "/_api/job/" + requestResult.headers["x-arango-async-id"], "");
    arangosh.checkRequestResult(jobResult);

    if (jobResult.code !== 204) {
      return jobResult;
    }

    if (++count % 6 === 0) {
      internal.print("still synchronizing, please wait...");
    }

    internal.sleep(5);
  }
};

////////////////////////////////////////////////////////////////////////////////
/// @brief queries the sync result status
////////////////////////////////////////////////////////////////////////////////

var getSyncResult = function(id) {
  var db = internal.db;

  var requestResult = db._connection.PUT_RAW("/_api/job/" + encodeURIComponent(id), "");
  arangosh.checkRequestResult(requestResult);

  if (requestResult.headers.hasOwnProperty("x-arango-async-id")) {
    return JSON.parse(requestResult.body);
  }

  return false;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief fetches a server's id
////////////////////////////////////////////////////////////////////////////////

var serverId = function() {
  var db = internal.db;

  var requestResult = db._connection.GET("/_api/replication/server-id");

  arangosh.checkRequestResult(requestResult);

  return requestResult.serverId;
};

exports.logger = logger;
exports.applier = applier;
exports.sync = sync;
exports.syncCollection = syncCollection;
exports.setupReplication = setupReplication;
exports.getSyncResult = getSyncResult;
exports.serverId = serverId;