let findAPITries = 0;
// Find SCORM 1.2 API algorithm taken from the SCORM documentation at:
// https://scorm.com/scorm-explained/technical-scorm/run-time/api-discovery-algorithms/
function findAPI(win) {
   // Check to see if the window (win) contains the API
   // if the window (win) does not contain the API and
   // the window (win) has a parent window and the parent window
   // is not the same as the window (win)
   while ( (win.API == null) && (win.parent != null) && (win.parent != win) )
   {
      // increment the number of findAPITries
      findAPITries++;
 
      // Note: 7 is an arbitrary number, but should be more than sufficient
      if (findAPITries > 7)
      {
         alert("Error finding API -- too deeply nested.");
         return null;
      }
 
      // set the variable that represents the window being
      // being searched to be the parent of the current window
      // then search for the API again
      win = win.parent;
   }
   return win.API;
}
 
function _getAPI() {
   // start by looking for the API in the current window
   var theAPI = findAPI(window);
 
   // if the API is null (could not be found in the current window)
   // and the current window has an opener window
   if ( (theAPI == null) && (window.opener != null) && (typeof(window.opener) != "undefined") )
   {
      // try to find the API in the current window’s opener
      theAPI = findAPI(window.opener);
   }
   // if the API has not been found
   if (theAPI == null)
   {
      // Alert the user that the API Adapter could not be found
      alert("Unable to find an API adapter");
   }
   return theAPI;
}


// SCORM 1.2 defines a bool as a string with the values "true" or "false"
function isScormTrue(b) {
	return b === "true";
}


class Scorm {
	api = null;
	// ensure LMSInitialize is only called once.
	initialized = false;
	// ensure LMSFinish is only called once.
	finished = false;

	getAPI() {
		if (this.api === null) {
			this.api = _getAPI();
		}
		return this.api;
	}

	initialize() {
		if (this.initialized) return true;
		const api = this.getAPI();
		if (!api) {
			console.warn("SCORM API not found");
			return false;
		}
		const r = api.LMSInitialize("");
		this.initialized = isScormTrue(r);
		return this.initialized;
	}

	finish() {
		if (this.finished) return true;
		const api = this.getAPI();
		if (!api) return false;
		const r = api.LMSFinish("");
		this.finished = isScormTrue(r);
		return this.finished;
	}

	getValue(el) {
		const api = this.getAPI();
		if (!api) return null;
		return api.LMSGetValue(el);
	}

	setValue(el, val) {
		const api = this.getAPI();
		if (!api) return false;
		const r = api.LMSSetValue(el, String(val));
		return isScormTrue(r);
	};

	commit() {
		const api = this.getAPI();
		if (!api) return false;
		const r = api.LMSCommit("");
		return isScormTrue(r);
	}

	setScore(raw, min, max) {
		this.setValue("cmi.core.score.raw", raw);
		if (min !== null) this.setValue("cmi.core.score.min", min);
		if (max !== null) this.setValue("cmi.core.score.max", max);
		this.commit();
	}
}

window.SCORM = new Scorm();

window.addEventListener("load", function() {
    window.SCORM.initialize();
});

// Finish on the before unloading the SCORM content as advised by the documentation:
// https://scorm.com/scorm-explained/technical-scorm/run-time/
window.addEventListener("beforeunload", function() {
    window.SCORM.commit();
    window.SCORM.finish();
});