/**
 * St. Petersburg paradox
 * by Kazuki Maeda
 * Last-Modified: Jul. 24, 2019
 */

var mode = ''
var numflip = 0;
var thread;
var prize = 0;
var numendless = 0;
var stat;
var fliptext;

window.onload = function(){
    document.getElementById('flip').addEventListener('click', flip, true);
    document.getElementById('challenges').addEventListener('click', challenges, true);
    document.getElementById('endless').addEventListener('click', endless, true);
}

function flip(){
    if(mode != 'flip'){
        if(mode != 'flipcontinue'){
            historytext = '';
        }

        document.getElementById('result').innerHTML = '';
        mode = 'flip';
        numflip = 0;
        fliptext = '';
    }
    var r = Math.floor(Math.random()*2);
    var addhistoryflag = false;
    var rchar;
    if(r){
        fliptext += '○ ';
        ++numflip;
    } else {
        fliptext += '×：' + Math.pow(2, numflip) + '円獲得！！';
        addhistoryflag = true;
        mode = 'flipcontinue';
    }
    document.getElementById('result').innerHTML
        = fliptext + '<hr><em>履歴：</em><br>' + historytext;
    if(addhistoryflag)
        historytext = fliptext + '<br>' + historytext;
}

function addstat(stat, n){
    if(typeof stat[n] === 'undefined')
        stat[n] = 1;
    else
        ++stat[n];
}

function challenges(){
    mode = 'challenges';
    var numchallenges = Math.floor(document.getElementById('numchallenges').value);
    prize = 0;
    var restext = '';
    var stat = [];
    document.getElementById('result').innerHTML = '';
    for(var k = 0; k < numchallenges; ++k){
        numflip = 0;
        while(1){
            var r = Math.floor(Math.random()*2);
            var rchar;
            if(r){
                restext += '○ ';
                ++numflip;
            } else {
                addstat(stat, numflip);
                var t = Math.pow(2, numflip);
                restext += '×：' + t + '円獲得！！<br>';
                prize += t;
            }
            if(!r)
                break;
        }
    }
    document.getElementById('result').innerHTML =
        numchallenges.toFixed() + '回挑戦した結果，合計獲得金額：' + prize.toFixed() + '円！！ 1回の平均獲得金額：' + (prize/numchallenges) + '円！！<hr>';
    for(var k = 0; k < stat.length; ++k){
        document.getElementById('result').innerHTML += '2<sup>' + k + '</sup>=' + Math.pow(2, k) +  '円獲得回数：';
        var t;
        if(typeof stat[k] === 'undefined')
            t = 0;
        else
            t = stat[k];
        document.getElementById('result').innerHTML += t + '回（' + (t/numchallenges*100) + '%）<br>';
    }
    document.getElementById('result').innerHTML += '<hr><em>履歴：</em><br>';
    document.getElementById('result').innerHTML += restext;
}

function endless(){
    if(mode != 'endless'){
        if(mode != 'inendless'){
            prize = 0;
            numendless = 0;
            stat = [];
        }
        mode = 'endless';
        thread = setInterval("endlessupdate();", 1000/60);
        document.getElementById('flip').disabled = true;
        document.getElementById('challenges').disabled = true;
        document.getElementById('endless').value = 'もう飽きた';
    } else {
        mode = 'inendless';
        document.getElementById('flip').disabled = false;
        document.getElementById('challenges').disabled = false;
        document.getElementById('endless').value = '飽きるまで挑戦し続ける';
        clearInterval(thread);
    }
}

function endlessupdate(){
    var speed = Math.floor(document.getElementById('speed').value);
    speed = speed <= 0 ? 1 : speed;
    for(var k = 0; k < speed; ++k){
        ++numendless;
        numflip = 0;
        while(1){
            var r = Math.floor(Math.random()*2);
            if(r){
                ++numflip;
            } else {
                addstat(stat, numflip);
                prize += Math.pow(2, numflip);
            }
            if(!r)
                break;
        }
    }

    document.getElementById('result').innerHTML
        = numendless.toFixed() + '回挑戦した結果，合計獲得金額：' + prize.toFixed() + '円！！ 1回の平均獲得金額：' + (prize/numendless).toFixed(16) + '円！！<hr>';
    for(var k = 0; k < stat.length; ++k){
        document.getElementById('result').innerHTML += '2<sup>' + k + '</sup>=' + Math.pow(2, k) + '円獲得回数：';
        var t;
        if(typeof stat[k] === 'undefined')
            t = 0;
        else
            t = stat[k];
        document.getElementById('result').innerHTML += t + '回（' + (t/numendless*100).toFixed(16) + '%）<br>';
    }
}