// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// dice.js
//
// copyright (c) 2006-2009 drow <drow@bin.sh>
// all rights reserved.

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// configuration

var fn = /([a-z]*)\(([^()]*?)\)/;
var dice = /(\d*)d(\d+)/;
var incr = /([+-]?\d+\.\d+|[+-]?\d+)(\+\+|--)/;
var mult = /([+-]?\d+\.\d+|[+-]?\d+)\s*(\*|\/|%)\s*([+-]?\d+\.\d+|[+-]?\d+)/;
var add  = /([+-]?\d+\.\d+|[+-]?\d+)\s*(\+|-)\s*([+-]?\d+\.\d+|[+-]?\d+)/;
var fp = /(\d+\.\d\d\d+)/;

var max_dice = 1000;

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// roll dice

function roll_dice (string) {
  var match;
  var result;

  while (string.match(fn)) {
    match = fn.exec(string);
    result = rd_fn(match[1],match[2]);
    string = string.replace(fn,result);
  }
  while (string.match(dice)) {
    match = dice.exec(string);
    result = rd_dice(match[1],match[2]);
    string = string.replace(dice,result);
  }
  while (string.match(incr)) {
    match = incr.exec(string);
    result = rd_math(match[1],match[2]);
    string = string.replace(incr,result);
  }
  while (string.match(mult)) {
    match = mult.exec(string);
    result = rd_math(match[1],match[2],match[3]);
    string = string.replace(mult,result);
  }
  while (string.match(add)) {
    match = add.exec(string);
    result = rd_math(match[1],match[2],match[3]);
    string = string.replace(add,result);
  }
  while (string.match(fp)) {
    match = fp.exec(string);
    result = Math.floor((match[1] * 100) + 0.5) / 100;
    string = string.replace(fp,result);
  }
  return string;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// functions

function rd_fn (fn,string) {
  var thr = roll_dice(string);

  if (fn == 'int') {
    return Math.floor(thr);
  } else if (fn == 'round') {
    return Math.floor(thr + 0.5);
  } else if (fn == 'sqrt') {
    return Math.sqrt(thr);
  }
  return thr;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// dice

function rd_dice (n,d) {
  n = parseInt(n);
    if (isNaN(n) || n < 1) n = 1;
  d = parseInt(d);
    if (isNaN(d) || d < 0) return 0;
  if (n > max_dice) return 0;

  var total = 0;

  var i; for (i = 0; i < n; i++) {
    total += rand(d) + 1;
  }
  return total;
}
function rand (d) {
  return Math.floor(Math.random() * 0.9999 * d);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// maths

function rd_math (a,op,b) {
  a = parseFloat(a);
    if (isNaN(a)) a = 0.0;
  b = parseFloat(b);
    if (isNaN(b)) b = 0.0;

  if (op == '++') return ++a;
  if (op == '--') return --a;
  if (op == '*')  return   a * b;
  if (op == '/')  return   a / b;
  if (op == '%')  return   a % b;
  if (op == '+')  return   a + b;
  if (op == '-')  return   a - b;

  return 0;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// multi-dice

function multi_dice (n,string) {
  var list = new Array();

  var i; for (i = 0; i < n; i++) {
    list.push(roll_dice(string));
  }
  return list.join(', ');
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// calculate average

function calc_avg (string) {
  var match;
  var result;

  while (string.match(dice)) {
    match = dice.exec(string);
    result = avg_dice(match[1],match[2]);
    string = string.replace(dice,result);
  }
  result = roll_dice(string);
  result = parseFloat(result);
    if (isNaN(result)) return 0;
  return result;
}
function avg_dice (n,d) {
  n = parseInt(n);
    if (isNaN(n) || n < 1) n = 1;
    if (n > max_dice) return 0;
  d = parseInt(d);
    if (isNaN(d) || d < 0) return 0;
  return (n * (d + 1)) / 2.0;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -