var error = require('./utils/error');
var utils = require('./utils/common');
var information = require('./information');

exports.AND = function() {
  var args = utils.flatten(arguments);
  var result = true;
  for (var i = 0; i < args.length; i++) {
    if (!args[i]) {
      result = false;
    }
  }
  return result;
};

exports.CHOOSE = function() {
  if (arguments.length < 2) {
    return error.na;
  }

  var index = arguments[0];
  if (index < 1 || index > 254) {
    return error.value;
  }

  if (arguments.length < index + 1) {
    return error.value;
  }

  return arguments[index];
};

exports.FALSE = function() {
  return false;
};

exports.IF = function(test, then_value, otherwise_value) {
  return test ? then_value : otherwise_value;
};

exports.IFERROR = function(value, valueIfError) {
  if (information.ISERROR(value)) {
    return valueIfError;
  }
  return value;
};

exports.IFNA = function(value, value_if_na) {
  return value === error.na ? value_if_na : value;
};

exports.NOT = function(logical) {
  return !logical;
};

exports.OR = function() {
  var args = utils.flatten(arguments);
  var result = false;
  for (var i = 0; i < args.length; i++) {
    if (args[i]) {
      result = true;
    }
  }
  return result;
};

exports.TRUE = function() {
  return true;
};

exports.XOR = function() {
  var args = utils.flatten(arguments);
  var result = 0;
  for (var i = 0; i < args.length; i++) {
    if (args[i]) {
      result++;
    }
  }
  return (Math.floor(Math.abs(result)) & 1) ? true : false;
};

exports.SWITCH = function () {
  var result;

  if (arguments.length > 0)  {
    var targetValue = arguments[0];
    var argc = arguments.length - 1;
    var switchCount = Math.floor(argc / 2);
    var switchSatisfied = false;
    var hasDefaultClause = argc % 2 !== 0;
    var defaultClause = argc % 2 === 0 ? null : arguments[arguments.length - 1];

    if (switchCount) {
      for (var index = 0; index < switchCount; index++) {
        if (targetValue === arguments[index * 2 + 1]) {
          result = arguments[index * 2 + 2];
          switchSatisfied = true;
          break;
        }
      }
    }

    if (!switchSatisfied) {
      result = hasDefaultClause ? defaultClause : error.na;
    }
  } else {
    result = error.value;
  }

  return result;
};