/*
RESCUE ROBOTICS WORKSHOP
Save to a file

                           Introduction to File IO
                                 Ron Kessler
                              Created 8/17/2018

Updated: 8/17/2018
				Did final compile/test. Saves one value of data to the NXT File (test.txt).


PURPOSE: While the datalogger is good for real time sensor testing, you may need to
				save data in your own format. This project shows how to save a reading to a file
				on the robot.

				Use the companion project called ReadFromFile to retrieve that one piece of data.


SETUP: 	You will see how to save a number to file, and determine if there was an error or not.
				We will start by defining the file and some other parameters the NXT needs.
				We will use "IOException" (exception = error) to see if there was any problem.
				YOU ALWAYS DO THIS WITH FILE IO, BLUETOOTH, OR WI-FI COMMUNICATIONS.
*/
task main()
{
	//---STEP 1: Define the stuff we need to access this file
	TFileHandle   fileNumber;								//internal number used to locate the file.
  TFileIOResult IOException;							//tells us if there is an error during the IO
  string        myFileName = "test.txt";	//my file name.
  int           fileSize = 100;						//same as when we saved 2 file
  short data2Save = 15;										//pretend this is data from a sensor.

	//---STEP 2: Tell the robot to delete the old file to start clean.
	Delete("test.txt",IOException);					//don't do this if you want to append to existing data!

  //---STEP 3: Now tell the NXT we want to save/write data to the file.
	//				Send it the 4 pieces of data (arguments) it needs in the parentheses.
  OpenWrite(fileNumber, IOException, myFileName, fileSize);	//creates the file if it doesn't exist

  //---STEP 4: MAKE IT SO! This takes value in data2Save and writes it to the file.
  WriteByte(fileNumber, IOException, data2Save);

  //---STEP 5: ALWAYS CLOSE THE FILE OR YOU WON'T BE ABLE TO ACCESS IT AGAIN.
  Close(fileNumber, IOException);

  //---STEP 6: Check if there was an error. If IOException = 0 then everything is fine. Otherwise no.
  nxtDisplayCenteredTextLine(1, "Rescue Robotics");
  nxtDisplayCenteredTextLine(2, "Saving data");

  if(IOException == 0)
  	nxtDisplayTextLine(5, "Data was saved!");
 	else
   	nxtDisplayTextLine(5, "Error while saving....");

   	wait1Msec(5000);			//let us see the result for a few seconds
}