var PROGRESS_BAR_FILL_START_BACKGROUND_X = -619;
var PROGRESS_BAR_FILL_END_BACKGROUND_X = -12;
var PROGRESS_CLOSE_INTERVAL_TIME_OUT = 200;
var PROGRESS_INTERVAL_TIME_OUT = 10;
var PROGRESS_SAME_ADD_COUNT = 0.00016;
var targetUnityInstance = null;
var targetProgress = 0;
var countUpProgress = 0;
var progressInterval = null;
var unityLoaderComplete = false;
var unityLoaderInstance = [];

// プログレスバーの更新処理開始
progressInterval = setInterval(updateProgress, PROGRESS_INTERVAL_TIME_OUT);

function UnityProgress(container, splashScreenStyle, progress) {
  if (!container)
    return;
  if (splashScreenStyle == null)
    return;
  if (!unityLoaderInstance.logo) {
    unityLoaderInstance.logo = document.createElement("div");
    unityLoaderInstance.logo.className = "logo " + splashScreenStyle;
    container.appendChild(unityLoaderInstance.logo);
  }
  if (!unityLoaderInstance.progress) {
    unityLoaderInstance.progress = document.createElement("div");
    unityLoaderInstance.progress.className = "progress " + splashScreenStyle;
    unityLoaderInstance.progress.empty = document.createElement("div");
    unityLoaderInstance.progress.empty.className = "empty";
    unityLoaderInstance.progress.appendChild(unityLoaderInstance.progress.empty);
    unityLoaderInstance.progress.full = document.createElement("div");
    unityLoaderInstance.progress.full.className = "full";
    unityLoaderInstance.progress.appendChild(unityLoaderInstance.progress.full);
    unityLoaderInstance.progress.fullBase = document.createElement("div");
    unityLoaderInstance.progress.fullBase.className = "fullBase";
    unityLoaderInstance.progress.appendChild(unityLoaderInstance.progress.fullBase);
    container.appendChild(unityLoaderInstance.progress);
  }
  if (!unityLoaderInstance.progressString) {
    unityLoaderInstance.progressString = document.createElement("div");
    unityLoaderInstance.progressString.className = "progressString " + splashScreenStyle;
    unityLoaderInstance.progressString.nowLoadingString = document.createElement("div");
    unityLoaderInstance.progressString.nowLoadingString.textContent = "Now Loading...";
    unityLoaderInstance.progressString.nowLoadingString.className = "nowLoadingString";
    unityLoaderInstance.progressString.appendChild(unityLoaderInstance.progressString.nowLoadingString);
    unityLoaderInstance.progressString.nowLoadingCount = document.createElement("div");
    unityLoaderInstance.progressString.nowLoadingCount.className = "nowLoadingCount";
    unityLoaderInstance.progressString.appendChild(unityLoaderInstance.progressString.nowLoadingCount);
    container.appendChild(unityLoaderInstance.progressString);
  }
  targetUnityInstance = unityLoaderInstance;
  targetProgress = progress < targetProgress?targetProgress:progress;

  // progressが1の場合はUnityLoaderの読み込みが完了した
  if (progress == 1) {
      unityLoaderComplete = true;
  }
}

/**
 * プログレスバーを更新する
 */
function updateProgress()
{
    // 初期化されていないなら抜ける
    if (targetUnityInstance == null) return;

    // 同数の場合は徐々にプログレスバーを進ませる
    if (countUpProgress == targetProgress) {
        targetProgress += PROGRESS_SAME_ADD_COUNT;
    }

    // 100%を超えないための制限
    if (1 < targetProgress){
        targetProgress = 1;
    }

    // 実際に読み込まれた進捗よりも進んでいないならプログレスバーを進ませる
    if (countUpProgress < targetProgress) {
      countUpProgress += Math.floor(Math.random()*1000)/200000;
      if (targetProgress < countUpProgress) countUpProgress = targetProgress;
    }

    // 読み込みが完了しているなら100%を一瞬見せるための
    if (unityLoaderComplete){
      countUpProgress = targetProgress;
      clearInterval(progressInterval);
      progressInterval = null;
      setTimeout(closeProgress, PROGRESS_CLOSE_INTERVAL_TIME_OUT);
    }

    // プログレスバー更新
    var progressRatio = (100 * countUpProgress);
    targetUnityInstance.progress.full.style.backgroundPositionX = ( PROGRESS_BAR_FILL_START_BACKGROUND_X + PROGRESS_BAR_FILL_END_BACKGROUND_X ) - ((progressRatio * ( PROGRESS_BAR_FILL_START_BACKGROUND_X - PROGRESS_BAR_FILL_END_BACKGROUND_X ) / 100) + PROGRESS_BAR_FILL_END_BACKGROUND_X ) + "px";

    // 進捗率更新
    targetUnityInstance.progressString.nowLoadingCount.textContent =progressRatio.toFixed(2) + "%";

}

/**
 * UnityLoaderのプログレスバー画面を閉じる
 */
function closeProgress()
{
    targetUnityInstance.logo.style.display = unityLoaderInstance.progress.style.display = unityLoaderInstance.progressString.style.display = "none";
    countUpProgress = 0;
    targetProgress = 0;
    targetUnityInstance = null;
}