#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<unistd.h>
#include<signal.h>
#include<X11/Xlib.h>
#define LENGTH(X)               (sizeof(X) / sizeof (X[0]))
#define CMDLENGTH		50

typedef struct {
	char* icon;
	char* command;
	unsigned int interval;
	unsigned int signal;
} Block;
char** last_updates;
void sighandler(int num);
void buttonhandler(int sig, siginfo_t *si, void *ucontext);
void replace(char *str, char old, char new);
void remove_all(char *str, char to_remove);
void getcmds(int time);
#ifndef __OpenBSD__
void getsigcmds(int signal);
void setupsignals();
void sighandler(int signum);
#endif
int getstatus(char *str, char *last);
void setroot();
void statusloop();
void termhandler(int signum);


#include "config.h"

static Display *dpy;
static int screen;
static Window root;
static char statusbar[LENGTH(blocks)][CMDLENGTH] = {0};
static char statusstr[2][512];
static int statusContinue = 1;
static void (*writestatus) () = setroot;

void replace(char *str, char old, char new)
{
	int N = strlen(str);
	for(int i = 0; i < N; i++)
		if(str[i] == old)
			str[i] = new;
}

void remove_all(char *str, char to_remove) {
	char *read = str;
	char *write = str;
	while (*read) {
		if (*read == to_remove) {
			read++;
			*write = *read;
		}
		read++;
		write++;
	}
}

//opens process *cmd and stores output in *output
void getcmd(const Block *block, char* last_update , char *output)
{
	if (block->signal)
	{
		output[0] = block->signal;
		output++;
	}
	strcpy(output, block->icon);
	char *cmd = block->command;
	FILE *cmdf = popen(cmd,"r");
	if (!cmdf)
		return;
	char c;
	int i = strlen(block->icon);
	fgets(output+i, CMDLENGTH-(strlen(delim)+1), cmdf);
	remove_all(output, '\n');
	if(i == strlen(output))
		strcpy(output+i, last_update);
	else
		strcpy(last_update, output+i);

	i = strlen(output);
	if ((i > 0 && block != &blocks[LENGTH(blocks) - 1]))
		strcat(output, delim);
	i+=strlen(delim);
	output[i++] = '\0';
	pclose(cmdf);
}

void getcmds(int time)
{
	const Block* current;
	for(int i = 0; i < LENGTH(blocks); i++)
	{
		current = blocks + i;
		if ((current->interval != 0 && time % current->interval == 0) || time == -1)
			getcmd(current,last_updates[i],statusbar[i]);
	}
}

#ifndef __OpenBSD__
void getsigcmds(int signal)
{
	const Block *current;
	for (int i = 0; i < LENGTH(blocks); i++)
	{
		current = blocks + i;
		if (current->signal == signal)
			getcmd(current,last_updates[i],statusbar[i]);
	}
}

void setupsignals()
{
	struct sigaction sa;

	for(int i = SIGRTMIN; i <= SIGRTMAX; i++)
		signal(i, SIG_IGN);

	for(int i = 0; i < LENGTH(blocks); i++)
	{
		if (blocks[i].signal > 0)
		{
			signal(SIGRTMIN+blocks[i].signal, sighandler);
			sigaddset(&sa.sa_mask, SIGRTMIN+blocks[i].signal);
		}
	}
	sa.sa_sigaction = buttonhandler;
	sa.sa_flags = SA_SIGINFO;
	sigaction(SIGUSR1, &sa, NULL);
	struct sigaction sigchld_action = {
  		.sa_handler = SIG_DFL,
  		.sa_flags = SA_NOCLDWAIT
	};
	sigaction(SIGCHLD, &sigchld_action, NULL);

}
#endif

int getstatus(char *str, char *last)
{
	strcpy(last, str);
	str[0] = '\0';
    for(int i = 0; i < LENGTH(blocks); i++) {
		strcat(str, statusbar[i]);
        if (i == LENGTH(blocks) - 1)
            strcat(str, " ");
    }
	str[strlen(str)-1] = '\0';
	return strcmp(str, last);//0 if they are the same
}

void setroot()
{
	if (!getstatus(statusstr[0], statusstr[1]))//Only set root if text has changed.
		return;
	Display *d = XOpenDisplay(NULL);
	if (d) {
		dpy = d;
	}
	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);
	XStoreName(dpy, root, statusstr[0]);
	XCloseDisplay(dpy);
}

void pstdout()
{
	if (!getstatus(statusstr[0], statusstr[1]))//Only write out if text has changed.
		return;
	printf("%s\n",statusstr[0]);
	fflush(stdout);
}


void statusloop()
{
#ifndef __OpenBSD__
	setupsignals();
#endif
  last_updates = malloc(sizeof(char*) * LENGTH(blocks));
  for(int i = 0; i < LENGTH(blocks); i++) {
    last_updates[i] = malloc(sizeof(char) * CMDLENGTH);
    strcpy(last_updates[i],"");
  }
	int i = 0;
	getcmds(-1);
	while(statusContinue)
	{
		getcmds(i);
		writestatus();
		sleep(1.0);
		i++;
	}
}

#ifndef __OpenBSD__
void sighandler(int signum)
{
	getsigcmds(signum-SIGRTMIN);
	writestatus();
}

void buttonhandler(int sig, siginfo_t *si, void *ucontext)
{
	char button[2] = {'0' + si->si_value.sival_int & 0xff, '\0'};
	pid_t process_id = getpid();
	sig = si->si_value.sival_int >> 8;
	if (fork() == 0)
	{
		const Block *current;
		for (int i = 0; i < LENGTH(blocks); i++)
		{
			current = blocks + i;
			if (current->signal == sig)
				break;
		}
		char shcmd[1024];
		sprintf(shcmd,"%s && kill -%d %d",current->command, current->signal+34,process_id);
		char *command[] = { "/bin/sh", "-c", shcmd, NULL };
		setenv("BLOCK_BUTTON", button, 1);
		setsid();
		execvp(command[0], command);
		exit(EXIT_SUCCESS);
	}
}

#endif

void termhandler(int signum)
{
  for(int i = 0; i < LENGTH(blocks); i++) {
    free(last_updates[i]);
  }
  free(last_updates);
	statusContinue = 0;
	exit(0);
}

int main(int argc, char** argv)
{
	for(int i = 0; i < argc; i++)
	{
		if (!strcmp("-d",argv[i]))
			delim = argv[++i];
		else if(!strcmp("-p",argv[i]))
			writestatus = pstdout;
	}
	signal(SIGTERM, termhandler);
	signal(SIGINT, termhandler);
	statusloop();
}
