function DBService() {
	this.path = this.getPath();
	this.directoryName = this.getDirectoryName(this.path);
	this.webPath = this.getWebPath(this.directoryName);

	this.maestroID = 0;
	this.playerID = 0;
	this.appName = "";
	this.dateTime = null;
}

DBService.prototype.getPath = function() {
	return window.location.pathname;
}

DBService.prototype.getDirectoryName = function(path) {
	var pathAndFileNames = path.split("/");
	return pathAndFileNames[pathAndFileNames.length - 2];
}

DBService.prototype.getWebPath = function(directoryName) {
	if(directoryName === "test")	// mouse_typing/test/
		return "../src/web/";
	else	// mousetyping/src/web/client/
		return "../";
}


DBService.prototype.setMaestroID = function(maestroID) {
	this.maestroID = maestroID;
}

DBService.prototype.setPlayerID = function(playerID) {
	this.playerID = playerID;
}

DBService.prototype.setAppName = function(appName) {
	this.appName = appName;
}

DBService.prototype.setDateTime = function(date, time) {
	this.dateTime = date + time;
}

DBService.prototype.resetDateTime = function() {
	this.dateTime = null;
}



DBService.prototype.makeXhr = function(filepath, onreadystatechange) {
	var xhr = new XMLHttpRequest();
	xhr.open("POST", this.webPath + filepath, true);
	xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	xhr.onreadystatechange = onreadystatechange;
	return xhr;
}

// tdd setup
DBService.prototype.tddSetup = function(command, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/db/tdd_setup.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send("command=" + command);
}

DBService.prototype.tddRun = function(command, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/db/tdd_run.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send("command=" + command);
}

// writing
DBService.prototype.requestWritingPlayerList = function(onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/writing/player_list.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send("maestroID=" + this.maestroID + "&playerID=" + this.playerID);
}

DBService.prototype.requestWritingInfo = function(writingID, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/writing/writing_info.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send("writingID=" + writingID);
}

// typing exam
DBService.prototype.addPrevHourTypingExamRecord = function(writingID, record, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/writing/update_result_record.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send(
		"maestroID=" + this.maestroID
		+ "&playerID=" + this.playerID
		+ "&writingID=" + writingID
		+ "&record=" + record
		+ "&isPrevHourFlag=true"
	);
}

DBService.prototype.updateTypingExamRecord = function(writingID, record, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/writing/update_result_record.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send(
		"maestroID=" + this.maestroID
		+ "&playerID=" + this.playerID
		+ "&writingID=" + writingID
		+ "&record=" + record
	);
}

DBService.prototype.getTypingExamHighestRecord = function(writingID, onSucceededListener, onFailedListener) {
	var xhr = this.makeXhr(
		"php/writing/get_highest_record.php",
		(function() {	// onreadystatechange
			if(xhr.readyState == 4 && xhr.status == 200) {
				var replyJSON = JSON.parse(xhr.responseText);

				if(replyJSON != null)
					onSucceededListener(replyJSON);
				else
					onFailedListener(replyJSON);
			}
		}).bind(this)
	);
	xhr.send(
		"maestroID=" + this.maestroID
		+ "&playerID=" + this.playerID
		+ "&writingID=" + writingID
	);
}