/*jshint strict: false */

////////////////////////////////////////////////////////////////////////////////
/// @brief database version check
///
/// @file
///
/// Checks if the database needs to be upgraded.
///
/// DISCLAIMER
///
/// Copyright 2014 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 Dr. Frank Celler
/// @author Copyright 2014, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

var cluster = require("@arangodb/cluster");
var fs = require("fs");
var db = require("@arangodb").db;
var console = require("console");

////////////////////////////////////////////////////////////////////////////////
/// @brief logger
////////////////////////////////////////////////////////////////////////////////

var logger = {
  info: function(msg) {
    console.log("In database '%s': %s", db._name(), msg);
  },

  error: function(msg) {
    console.error("In database '%s': %s", db._name(), msg);
  },

  log: function(msg) {
    this.info(msg);
  }
};

////////////////////////////////////////////////////////////////////////////////
/// @brief CURRENT_VERSION
////////////////////////////////////////////////////////////////////////////////

exports.CURRENT_VERSION = (function() {
  var v = db._version().replace(/-[a-zA-Z0-9_\-]*$/g, '').split('.');

  var major = parseFloat(v[0], 10) || 0;
  var minor = parseFloat(v[1], 10) || 0;
  var patch = parseFloat(v[2], 10) || 0;

  return (((major * 100) + minor) * 100) + patch;
}());

////////////////////////////////////////////////////////////////////////////////
/// @brief VERSION_MATCH
////////////////////////////////////////////////////////////////////////////////

exports.VERSION_MATCH = 1;

////////////////////////////////////////////////////////////////////////////////
/// @brief DOWNGRADE
////////////////////////////////////////////////////////////////////////////////

exports.DOWNGRADE_NEEDED = 2;

////////////////////////////////////////////////////////////////////////////////
/// @brief UPGRADE
////////////////////////////////////////////////////////////////////////////////

exports.UPGRADE_NEEDED = 3;

////////////////////////////////////////////////////////////////////////////////
/// @brief IS_CLUSTER
////////////////////////////////////////////////////////////////////////////////

exports.IS_CLUSTER = -1;

////////////////////////////////////////////////////////////////////////////////
/// @brief CANNOT_PARSE_VERSION_FILE
////////////////////////////////////////////////////////////////////////////////

exports.CANNOT_PARSE_VERSION_FILE = -2;

////////////////////////////////////////////////////////////////////////////////
/// @brief CANNOT_READ_VERSION_FILE
////////////////////////////////////////////////////////////////////////////////

exports.CANNOT_READ_VERSION_FILE = -3;

////////////////////////////////////////////////////////////////////////////////
/// @brief NO_VERSION_FILE
////////////////////////////////////////////////////////////////////////////////

exports.NO_VERSION_FILE = -4;

////////////////////////////////////////////////////////////////////////////////
/// @brief NO_SERVER_VERSION
////////////////////////////////////////////////////////////////////////////////

exports.NO_SERVER_VERSION = -5;

////////////////////////////////////////////////////////////////////////////////
/// @brief checks the version
////////////////////////////////////////////////////////////////////////////////

exports.databaseVersion = function() {
  if (cluster.isCoordinator()) {
    console.debug("skip on corrdinator");

    return {
      result: exports.IS_CLUSTER
    };
  }

  // path to the VERSION file
  var versionFile = db._path() + "/VERSION";
  var lastVersion = null;

  // VERSION file exists, read its contents
  if (fs.exists(versionFile)) {
    var versionInfo = fs.read(versionFile);
    console.debug("found version file: " + versionInfo);

    if (versionInfo !== '') {
      var versionValues = JSON.parse(versionInfo);

      if (versionValues && versionValues.version && !isNaN(versionValues.version)) {
        lastVersion = parseFloat(versionValues.version);
      } else {
        logger.error("Cannot parse VERSION file '" + versionFile + "': '" + versionInfo + "'");
        return {
          result: exports.CANNOT_PARSE_VERSION_FILE
        };
      }
    } else {
      logger.error("Cannot read VERSION file: '" + versionFile + "'");
      return {
        result: exports.CANNOT_READ_VERSION_FILE
      };
    }
  } else {
    console.debug("version file (" + versionFile + ") not found");

    return {
      result: exports.NO_VERSION_FILE
    };
  }

  // extract server version
  var currentVersion = exports.CURRENT_VERSION;

  // version match!
  if (Math.floor(lastVersion / 100) === Math.floor(currentVersion / 100)) {
    console.debug("version match: last version " + lastVersion +
      ", current version " + currentVersion);

    return {
      result: exports.VERSION_MATCH,
      serverVersion: currentVersion,
      databaseVersion: lastVersion
    };
  }

  // downgrade??
  if (lastVersion > currentVersion) {
    console.debug("downgrade: last version " + lastVersion +
      ", current version " + currentVersion);

    return {
      result: exports.DOWNGRADE_NEEDED,
      serverVersion: currentVersion,
      databaseVersion: lastVersion
    };
  }

  // upgrade
  if (lastVersion < currentVersion) {
    console.debug("upgrade: last version " + lastVersion +
      ", current version " + currentVersion);

    return {
      result: exports.UPGRADE_NEEDED,
      serverVersion: currentVersion,
      databaseVersion: lastVersion
    };
  }

  console.error("should not happen: last version " + lastVersion +
    ", current version " + currentVersion);

  return {
    result: exports.NO_VERSION_FILE
  };
};