#include <sys/types.h>
#include <sys/stat.h>
#include <glib.h>
#include <stdbool.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

#include "piper_webext.h"

static int pipe_out_fd;
static void (*pipe_in_callback)(char *msg);

// returns full path to pipe in users runtime dir.
// dont forge't to g_free after use
static gchar* getpath(char *path)
{
    return g_strdup_printf("%s/piper-%s",g_get_user_runtime_dir(),path);
}

// callback function wrapper for received messages
static gboolean mycallback(GIOChannel *ch, GIOCondition c, gpointer p)
{
    gchar *line;
    g_io_channel_read_line(ch, &line, NULL, NULL, NULL);
    g_strchomp(line);
    pipe_in_callback(line);
    g_free(line);
    return true;
}

static void register_callback(char *path)
{
	gchar *fullpath=getpath(path);
	mkfifo(fullpath,0600);
	GMainContext *ctx = g_main_context_default();
	GIOChannel *io = g_io_channel_new_file(fullpath, "r+", NULL);
	GSource *watch = g_io_create_watch(io, G_IO_IN);
	g_source_attach(watch,ctx);
	g_source_set_callback(watch,(GSourceFunc)mycallback,NULL,NULL);
	g_free(fullpath);
}

// open for writing, lock and return pipe fd
static int piper_lock(char *path)
{
	gchar *fullpath=getpath(path);
	mkfifo(fullpath,0600);
	int pipe=open(fullpath, O_RDWR | O_CREAT | O_TRUNC);
	g_free(fullpath);
	if(pipe == -1) return -1;
	int lock=lockf(pipe,F_TLOCK,0);
	if(lock == -1) return -1;
	return pipe;
}

void piper_init(char *path_in,char *path_out,void (*callback_func)(char *msg))
{
	pipe_in_callback=callback_func;
        pipe_out_fd=piper_lock(path_out);
	if(pipe_out_fd==-1)
	{
	    g_print("can not get exclusive lock! Bailing out.\n");
	    exit(0);
	}
	register_callback(path_in);
}

void piper_send(char *msg)
{
        int ret=write(pipe_out_fd,msg,strlen(msg));
	if(ret==-1)g_print("Can not write to pipe :(\n");
}