// C_application.c : A demonstration of the C programing languge and use with Phidgets.
//Uses a Phidget interface kit with a slider or rotation sensor attached to port 0 and a Phidget servo.

#include <signal.h>
//Used to intercept the Ctrl-C Command used to exit the program

#include <conio.h>
//Provides access to the _getch() function

#include <iostream>
//Provides access to the cout function

#include <windows.h>
//Provides access to the sleep() function

#include "phidget21.h" //ensure you have this .h file in the same directory as this file
//Provides access to all Phidget functions and handles

using namespace std;
//Sets the default namespace which removes the need for std:: in front of the cout function

CPhidgetServoHandle servo;
//Defines the global Phidget servo handle

static int exitnow = 0;
//Global variable to determine when the program should exit.

int __stdcall attach_handler(CPhidgetHandle phid, void *userPtr) {
	//Function called whenever a Phidget is attached

	const char *namePtr;
	CPhidget_getDeviceName(phid, &namePtr);
	//Creates a pointer that points to the name of the Phidget

	cout << namePtr <<" Attached\n";
	//Writes to the command line to show that a Phidget has been attached

	return 0;
}

int __stdcall detach_handler(CPhidgetHandle phid, void *userPtr) {
	//Function called whenever a Phidget is detached

	cout << (char *)userPtr << " Detached\n";
	//Displays the name of the Phidget as determined by the programer in the main function

	return 0;
}

int __stdcall ifk_sensor_change_handler
	(CPhidgetInterfaceKitHandle phid, 
		void *userPtr, 
		int SIndex, 
		int SValue) {
	//Function called whenever the Phidget21 library detects a sensor change

	if (SIndex == 0) //Determines if the sensor experiencing the change is at index 0.
	{
		int sensor_value = 0;

		sensor_value = SValue;
		CPhidgetInterfaceKit_getSensorValue
			(phid, 
				0, 
				&sensor_value);
		//Both lines do the exact same thing and only one need be used. They are responsible for determining the value of the sensor at index 0.

		sensor_value = (int)(sensor_value * .18);
		//Converts the sensors value from its input range of 0 - 999 to a range of 0-180 which the Phidget servo can use to deterimine a position

		CPhidgetServo_setMotorPosition
			(servo, 
				0, 
				sensor_value);
		//Sets the position of the servo
	}

	return 0;
}

void sighandler (int n) {
	//Function to handle termination signals

    printf ("Got a signal. Exiting.\n");
    exitnow = 1;
	//Sets the exitnow variable to signal program termination
}

int main(char argv[]) {
	//Main function called when the program loads

	char ifk_name[4] = "IFK";
	char servo_name[6] = "Servo";
	//Defines names for the Phidgets

	char exitcode = 0;

	signal (SIGTERM, sighandler);
	//Assigns the sighandler() function to handle SIGTERM which is a generic termination command
	signal (SIGINT, sighandler);
	//Assigns the sighandler() function to handle SIGINT which is the Ctrl-C key command

	CPhidgetInterfaceKitHandle ifk;
	CPhidgetInterfaceKit_create(&ifk);
	CPhidget_set_OnAttach_Handler((CPhidgetHandle)ifk, attach_handler, NULL);
	CPhidget_set_OnDetach_Handler((CPhidgetHandle)ifk, detach_handler, &ifk_name);
	CPhidgetInterfaceKit_set_OnSensorChange_Handler(ifk, ifk_sensor_change_handler, NULL);
	CPhidget_open((CPhidgetHandle)ifk, -1);
	//All of the Phidget initilization instructions for the interface kit.

	CPhidget_waitForAttachment((CPhidgetHandle)ifk, 10000);
	//Have to wait to ensure that phidget has been attached before attempting to do anything with it or to recieve events

	CPhidgetServo_create(&servo);
	CPhidget_set_OnAttach_Handler((CPhidgetHandle)servo, attach_handler, NULL);
	CPhidget_set_OnDetach_Handler((CPhidgetHandle)servo, detach_handler, &servo_name);
	CPhidget_open((CPhidgetHandle)servo, -1);
	//All of the Phidget initilization instructions for the servo.

	CPhidget_waitForAttachment((CPhidgetHandle)servo, 10000);
	//Have to wait to ensure that phidget has been attached before attempting to do anything with it or to recieve events

	while(exitcode!= 'q')
		exitcode = _getch();
	//The first method to exit the program. This method can only be used in windows and exits on q being pressed

	//while(exitcode!= 'q')
	//	scanf("%c", &exitcode);
	//The second method to exit the program. Exits on q[enter]
	
	//while(!exitnow) Sleep(500);
	//The third method to exit the program. Exits on CTRL+C using the signal handlers.

	CPhidget_close((CPhidgetHandle)ifk);
	CPhidget_close((CPhidgetHandle)servo);
	CPhidget_delete((CPhidgetHandle)ifk);
	CPhidget_delete((CPhidgetHandle)servo);
	//Closes and deletes Phidget handles. Handles always need to be deleted when they are no longer needed or fall out of scope to prevent memory leaks.

	return 0;
}