"use strict";

var MongoError = require('mongodb-core').MongoError

var shallowClone = function(obj) {
  var copy = {};
  for(var name in obj) copy[name] = obj[name];
  return copy;
}

// Set simple property
var getSingleProperty = function(obj, name, value) {
  Object.defineProperty(obj, name, {
    enumerable:true,
    get: function() {
      return value 
    }
  });  
}

var formatSortValue = exports.formatSortValue = function(sortDirection) {
  var value = ("" + sortDirection).toLowerCase();

  switch (value) {
    case 'ascending':
    case 'asc':
    case '1':
      return 1;
    case 'descending':
    case 'desc':
    case '-1':
      return -1;
    default:
      throw new Error("Illegal sort clause, must be of the form "
                    + "[['field1', '(ascending|descending)'], "
                    + "['field2', '(ascending|descending)']]");
  }
};

var formattedOrderClause = exports.formattedOrderClause = function(sortValue) {
  var orderBy = {};
  if(sortValue == null) return null;
  if (Array.isArray(sortValue)) {
    if(sortValue.length === 0) {
      return null;
    }

    for(var i = 0; i < sortValue.length; i++) {
      if(sortValue[i].constructor == String) {
        orderBy[sortValue[i]] = 1;
      } else {
        orderBy[sortValue[i][0]] = formatSortValue(sortValue[i][1]);
      }      
    }
  } else if(sortValue != null && typeof sortValue == 'object') {
    orderBy = sortValue;
  } else if (typeof sortValue == 'string') {
    orderBy[sortValue] = 1;
  } else {
    throw new Error("Illegal sort clause, must be of the form " +
      "[['field1', '(ascending|descending)'], ['field2', '(ascending|descending)']]");
  }

  return orderBy;
};

var checkCollectionName = function checkCollectionName (collectionName) {
  if('string' !== typeof collectionName) {
    throw Error("collection name must be a String");
  }

  if(!collectionName || collectionName.indexOf('..') != -1) {
    throw Error("collection names cannot be empty");
  }

  if(collectionName.indexOf('$') != -1 &&
      collectionName.match(/((^\$cmd)|(oplog\.\$main))/) == null) {
    throw Error("collection names must not contain '$'");
  }

  if(collectionName.match(/^\.|\.$/) != null) {
    throw Error("collection names must not start or end with '.'");
  }

  // Validate that we are not passing 0x00 in the colletion name
  if(!!~collectionName.indexOf("\x00")) {
    throw new Error("collection names cannot contain a null character");
  }
};

var handleCallback = function(callback, err, value1, value2) {
  try {
    if(callback == null) return;
    if(value2) return callback(err, value1, value2);
    return callback(err, value1);
  } catch(err) {
    process.nextTick(function() { throw err; });
    return false;
  }

  return true;
}

/**
 * Wrap a Mongo error document in an Error instance
 * @ignore
 * @api private
 */
var toError = function(error) {
  if (error instanceof Error) return error;

  var msg = error.err || error.errmsg || error.errMessage || error;
  var e = new MongoError(msg);

  // Get all object keys
  var keys = typeof error == 'object'
    ? Object.keys(error)
    : [];

  for(var i = 0; i < keys.length; i++) {
    e[keys[i]] = error[keys[i]];
  }

  return e;
}

/**
 * @ignore
 */
var normalizeHintField = function normalizeHintField(hint) {
  var finalHint = null;

  if(typeof hint == 'string') {
    finalHint = hint;
  } else if(Array.isArray(hint)) {
    finalHint = {};

    hint.forEach(function(param) {
      finalHint[param] = 1;
    });  
  } else if(hint != null && typeof hint == 'object') {
    finalHint = {};
    for (var name in hint) {
      finalHint[name] = hint[name];
    }    
  }

  return finalHint;
};

/**
 * Create index name based on field spec
 *
 * @ignore
 * @api private
 */
var parseIndexOptions = function(fieldOrSpec) {
  var fieldHash = {};
  var indexes = [];
  var keys;

  // Get all the fields accordingly
  if('string' == typeof fieldOrSpec) {
    // 'type'
    indexes.push(fieldOrSpec + '_' + 1);
    fieldHash[fieldOrSpec] = 1;
  } else if(Array.isArray(fieldOrSpec)) {
    fieldOrSpec.forEach(function(f) {
      if('string' == typeof f) {
        // [{location:'2d'}, 'type']
        indexes.push(f + '_' + 1);
        fieldHash[f] = 1;
      } else if(Array.isArray(f)) {
        // [['location', '2d'],['type', 1]]
        indexes.push(f[0] + '_' + (f[1] || 1));
        fieldHash[f[0]] = f[1] || 1;
      } else if(isObject(f)) {
        // [{location:'2d'}, {type:1}]
        keys = Object.keys(f);
        keys.forEach(function(k) {
          indexes.push(k + '_' + f[k]);
          fieldHash[k] = f[k];
        });
      } else {
        // undefined (ignore)
      }
    });
  } else if(isObject(fieldOrSpec)) {
    // {location:'2d', type:1}
    keys = Object.keys(fieldOrSpec);
    keys.forEach(function(key) {
      indexes.push(key + '_' + fieldOrSpec[key]);
      fieldHash[key] = fieldOrSpec[key];
    });
  }

  return {
    name: indexes.join("_"), keys: keys, fieldHash: fieldHash
  }
}

var isObject = exports.isObject = function (arg) {
  return '[object Object]' == toString.call(arg)
}

var debugOptions = function(debugFields, options) {
  var finaloptions = {};
  debugFields.forEach(function(n) {
    finaloptions[n] = options[n];
  });

  return finaloptions;
}

var decorateCommand = function(command, options, exclude) {
  for(var name in options) {
    if(exclude[name] == null) command[name] = options[name];
  }

  return command;
}

exports.shallowClone = shallowClone;
exports.getSingleProperty = getSingleProperty;
exports.checkCollectionName = checkCollectionName;
exports.toError = toError;
exports.formattedOrderClause = formattedOrderClause;
exports.parseIndexOptions = parseIndexOptions;
exports.normalizeHintField = normalizeHintField;
exports.handleCallback = handleCallback;
exports.decorateCommand = decorateCommand;
exports.isObject = isObject;
exports.debugOptions = debugOptions;