// Standard c and unix libraries
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>

// Threading
#include <pthread.h>
//Input management
#include <linux/input.h>
#include <linux/uinput.h>
// Joystick reading
#include <linux/joystick.h>

// ALL OF MY FUNCTIONS EXIT ON ERROR
// Gets a single input event and returns it.
struct js_event getAnInput(FILE *file);

// Creates/opens the uinput device (returns filedescriptor)
int createUinput();
// Configures the event types based on an array argv
void configEvtype(int argc, int* argv,int fd);
// Configure the keys usable based on an array argv
void configKeys(int argc, int* argv, int fd);
// Configures the relitive axis usable based on array argv
void configRel(int argc, int* argv, int fd);
// Configure the virtual device and submits it to the filedescriptor
void configureDevice(int fd, char* name, int vendor, int product, int version);
// Send a single event
void sendEvent(int fd, int type, int code, int value);
// Macro to send and then sync an event
#define SendAndSync(fd,type,code,value) sendEvent(fd,type,code,value);sendEvent(fd,EV_SYN,0,0);
// A pthread function which performs mouse axis movements constantly
void *axisThreadLoop(void *ptr);

// A record of which axis are pressed, and how much (the last one is for speed of motion on axis)
int axisLog[7] = {0,0,0,0,0,0,1};

int main(int argc, char* argv[]) {
	// Want root for the uinput device
	if (getuid()!=0) {
		printf("You must be root to use the uinput device, self escalating with sudo\n");
		printf("Hopefully you didnt change the program name\n");
		system("sudo ./ouycraft");
		exit(0);
	}
	printf("The program is running as root\n");
	// Open the joystick device
	FILE *file;
	// Either opens to the given joystick, or if none is given, js0
	file=fopen(argc==2?argv[1]:"/dev/input/js0","rb");
	if (!file) {
		printf("File not opened/found\n");
		exit(1);
	}

	// Creates the uinput device (returns filedescriptor)
	int fd = createUinput();

	// Configures the evtype to sync, relitive axis, and syncing
	int bits[3] = {EV_KEY,EV_REL,EV_SYN};
	configEvtype(3, bits,fd);

	// Configure the keys usable W,S,A,D,ESC,SPACE,E,leftclick,rightclick,middleclick,leftshift
	int keys[11] = {KEY_W,KEY_S,KEY_D,KEY_ESC,KEY_SPACE,KEY_A,KEY_E,BTN_LEFT,BTN_RIGHT,BTN_MIDDLE,KEY_LEFTSHIFT};
	configKeys(11, keys,fd);

	// Configure the x and y mouse axis, and the wheel motion
	int rel[3] = {REL_X,REL_Y,REL_WHEEL};
	configRel(3,rel,fd);

	// Configure the virtual device for uinput
	configureDevice(fd, "ouyInputDevice", 0x1234, 0x5678, 1);
	// Tell uinput to now create our device
	int ret = ioctl(fd,UI_DEV_CREATE);
	if (ret < 0) {
		printf("Error creating dev\n");
		exit(1);
	}
	printf("Congratulations, everything is configure, please wait a second");
	sleep(1);
	printf("Ready to run joystick actions!\n");

	// Thread to control the axis, needs the filedescriptor too
	pthread_t axisThread;
	int retval = pthread_create( &axisThread, NULL, axisThreadLoop, (void*)&fd);
	if (retval) {printf("Thread not created, exiting\n");exit(1);}

	// A main loop for the program
	while (1) {
		// jevent is not java event, but joystick event, its read in every while loop
		struct js_event jevent = getAnInput(file);
		// If jevent.type = 2 then its a axis movement with extra possible values
		if (jevent.type == 2) {
			// axis
			switch(jevent.number) {
				// Move left or right (left joystick x)
				case 0:
					if (axisLog[0] == 1  && jevent.value>=10) break;
					if (axisLog[0] == 0  && jevent.value<=10 && jevent.value>=-10) break;
					if (axisLog[0] == -1 && jevent.value<=-10) break;
					if (axisLog[0] == 1  && jevent.value<10) {SendAndSync(fd,EV_KEY,KEY_D,0); axisLog[0]=0;}
					if (axisLog[0] == -1 && jevent.value>-10) {SendAndSync(fd,EV_KEY,KEY_A,0);axisLog[0]=0;}
					if (axisLog[0] == 0 && jevent.value<=-10) {SendAndSync(fd,EV_KEY,KEY_A,1);axisLog[0]=-1;}
					if (axisLog[0] == 0 && jevent.value>=10) {SendAndSync(fd,EV_KEY,KEY_D,1);axisLog[0]=1;}
					break;
				// Move forward or backwards (left joystick y)
				case 1:
					if (axisLog[1] == 1  && jevent.value>=10) break;
					if (axisLog[1] == 0  && jevent.value<=10 && jevent.value>=-10) break;
					if (axisLog[1] == -1 && jevent.value<=-10) break;
					if (axisLog[1] == 1  && jevent.value<10) {SendAndSync(fd,EV_KEY,KEY_S,0); axisLog[1]=0;}
					if (axisLog[1] == -1 && jevent.value>-10) {SendAndSync(fd,EV_KEY,KEY_W,0);axisLog[1]=0;}
					if (axisLog[1] == 0 && jevent.value<=-10) {SendAndSync(fd,EV_KEY,KEY_W,1);axisLog[1]=-1;}
					if (axisLog[1] == 0 && jevent.value>=10) {SendAndSync(fd,EV_KEY,KEY_S,1);axisLog[1]=1;}
					break;
				// Select an item to the left (left trigger)
				case 2:
					if (axisLog[2] == jevent.value>=-32760 || axisLog[2]) break;
					axisLog[2] = jevent.value>=-32760;
					SendAndSync(fd,EV_REL,REL_WHEEL,-1);
					break;
				// just copy the mousemove for x, (right joystick x)
				case 3:
					axisLog[3] = jevent.value;
					break;
				// Just copy the mousemove for y, (right joystick y)
				case 4:
					axisLog[4] = jevent.value;
					break;
				// Select an item to the right (right trigger)
				case 5:
					if (axisLog[5] == jevent.value>=-32760 || axisLog[5]) break;
					axisLog[5] = jevent.value>=-32760;
					SendAndSync(fd,EV_REL,REL_WHEEL,1);
					break;
			}
		// If jevent.type = 1 its a simple button press
		} else if (jevent.type == 1) {
			// button
			switch (jevent.number) {
				// PS x Equivlent(jump)
				case 0: SendAndSync(fd,EV_KEY,KEY_SPACE,jevent.value);break;
				// PS circle equivlent (open inventory and slow mouse)
				case 3: SendAndSync(fd,EV_KEY,KEY_E,jevent.value);if (jevent.value) {axisLog[6]= !axisLog[6];}break;
				// Left bumper (place block)
				case 4:	SendAndSync(fd,EV_KEY,BTN_RIGHT,jevent.value);break;//if(jevent.value){SendAndSync(fd,EV_REL,REL_WHEEL,1);}break;
				// Right bumper (remove block)
				case 5: SendAndSync(fd,EV_KEY,BTN_LEFT,jevent.value);break;//if (jevent.value){SendAndSync(fd,EV_REL,REL_WHEEL,-1);}break;
				// Left stick click (shiftwalk)
				case 6: SendAndSync(fd,EV_KEY,KEY_LEFTSHIFT,jevent.value);break;
				// Right stick click (copy block)
				case 7: SendAndSync(fd,EV_KEY,BTN_MIDDLE,jevent.value);break;
				// Dpad down (slow mouse)
				case 9: if (jevent.value) {axisLog[6]= !axisLog[6];}break;
				//case 12: SendAndSync(fd,EV_KEY,BTN_RIGHT,jevent.value);break;
				//case 13: SendAndSync(fd,EV_KEY,BTN_LEFT,jevent.value);break;
				// Home button (open menu)
				case 14: SendAndSync(fd,EV_KEY,KEY_ESC,jevent.value);break;
			}
		// Ignore all other messages, (joystick initialization actions)
		} else continue;
	}
}

// Get a single input event, and return it
struct js_event getAnInput(FILE *file) {
	struct js_event jevent;
	int returnvalue = fread(&jevent,sizeof(jevent),1, file);
	if (returnvalue<0) {printf("file failed read\n");exit(1);}
	return jevent;
}

// Deal with the axis on a time based loop, prevents blocking from fread on the js0 file
void *axisThreadLoop(void *ptr)	{
	// Restore the filedescriptor
	int fd = * (int*) ptr;

	// get the current time for usage later
	clock_t start = clock();
	clock_t cur;

	// Loop for the events,(never exits)
	while (1) {
		// get the current time of the loop start
		cur = clock();
		// clock() calls can rap arround after about 75 minutes, should only hickup this way
		if (cur-start < 0) start=clock();
		// Wait a consistent time
		if (cur-start <= 10000) continue;
		// Reset the start time
		start = clock();
		// The axisLog[6] is to change the mouse speed, helpful for menus
		// The x axis is sent first but not synced
		sendEvent(fd,EV_REL,REL_X,(int)axisLog[3]/(axisLog[6]?1900:4000));
		// The y axis is sent, and we can sync it now, so now x and y are synced
		SendAndSync(fd,EV_REL,REL_Y,(int)axisLog[4]/(axisLog[6]?1900:4000));
	}
}

// Send our event into the uevent descriptor
void sendEvent(int fd, int type, int code, int value) {
	// The event to be sent
	struct input_event ev;
	// 0 out all the values(i was told to)
	memset(&ev,0,sizeof(ev));
	// Copy in the type, code, and value
	ev.type = type;
	ev.code = code;
	ev.value = value;

	//POTENTIAL BUG? i dont know what the write shoudl return, il leave asis
	if (write(fd,&ev,sizeof(ev))<=0) {
		printf("Error write\n");
		exit(1);
	}
}

// Configure the ev types based on the loop
void configEvtype(int argc, int* argv,int fd) {
	int ret;
	for (int i = 0; i < argc; i++) {
		// Ioctl configures the ui_set_evbit for me
		ret = ioctl(fd,UI_SET_EVBIT,argv[i]);
		if (ret < 0) {
			printf("Error setevntype %i\n",i);
			exit(1);
		}
	}
}

// same as configevtype but with keys
void configKeys(int argc, int* argv, int fd) {
	int ret;
	for (int i = 0; i < argc; i++) {
		ret = ioctl(fd,UI_SET_KEYBIT,argv[i]);
		if (ret < 0) {
			printf("Error setkey %i\n",i);
			exit(1);
		}
	}
}

// same as configevtype but with relitive events
void configRel(int argc, int* argv, int fd) {
	int ret;
	for (int i = 0; i < argc; i++) {
		ret = ioctl(fd,UI_SET_RELBIT,argv[i]);
		if (ret < 0) {
			printf("Error setrel %i\n",i);
			exit(1);
		}
	}
}

// Create a fake device for our uevent
void configureDevice(int fd, char* name, int vendor, int product, int version) {
	struct uinput_user_dev uidev;
	memset(&uidev,0,sizeof(uidev));
	snprintf(uidev.name,UINPUT_MAX_NAME_SIZE,name);
	uidev.id.bustype=BUS_USB;
	uidev.id.vendor=vendor;
	uidev.id.product=product;
	uidev.id.version=version;

	int ret = write(fd,&uidev,sizeof(uidev));
	if (ret < 0) {
		printf("Error on writing thing\n");
		exit(1);
	}
}

// Create an input device based on /dev/uinput or /dev/input/uinput
int createUinput() {
	int fd;
	// On my system its /dev/uinput, on some it may be /dev/input/uinput. lets try both
	fd = open("/dev/uinput",O_WRONLY | O_NONBLOCK);
	if (fd < 0) {
		printf("Failed to open file, Trying other input device\n");
		fd = open("/dev/input/uinput",O_WRONLY | O_NONBLOCK);
		if (fd < 0) {
			printf("No luck on input files, exiting\n");
			exit(1);
		}
	}
	return fd;
}