#include <stdio.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "MESA_shm_ring_queue.h"

#define BUFSIZE    256
void init_ring_queue_head_arrray(struct MESA_shm_overview *ovw, struct MESA_shm_queue_head **ring_queue_head)
{
	int i = 0;
	struct MESA_shm_overview *tmp_ovw = NULL;
	for(i = 0; i< MESA_SHM_RING_QUEUE_NUM; i++){
		tmp_ovw = ovw + i;
		if(tmp_ovw->shmid == -1){
			break;
		}
		ring_queue_head[i] = shmat(tmp_ovw->shmid, NULL, 0);		
	}
	return ;
}
void consumer_daemo()
{
	int fd = -1;
	switch (fork()) {
	    case -1:
	        printf("fork error\n");
	        return ;
	    case 0:
	        break;
	    default:
	        exit(0);
    }
	if (setsid() == -1) {
        return ;
    }
	umask(0);
	fd = open("/dev/null", O_RDWR);
    if (fd == -1) {
        return ;
    }
	if (dup2(fd, STDIN_FILENO) == -1) {
        return ;
    }

    if (dup2(fd, STDOUT_FILENO) == -1) {
        return ;
    }
	if (fd > STDERR_FILENO) {
        if (close(fd) == -1) {
            return ;
        }
    }
	return ;
}
int consumer_is_running(char *process_name)
{
	FILE *fp = NULL;
	char buf[BUFSIZE] = {0};
	int count = 0;
	char command[BUFSIZE] = {0};
	if(process_name == NULL){
		return 0;
	}
	snprintf(command, sizeof(command), "ps -ef | grep %s | grep -v grep | wc -l", process_name);
	fp = popen(command, "r");
	if(fp == NULL){
		return 0;
	}
	if((fgets(buf, sizeof(buf), fp)) != NULL){
		count = atoi(buf);
	}
	pclose(fp);
	if(count > 1){
		return 1;
	}else{
		return 0;
	}
	return 0;
}
char *get_exe_name(char *argv)
{
	char * p = NULL;
	p = rindex(argv, '/');
	if(p == NULL){
		p = argv;
	}else{
		p = p + 1;
	}
	return p;
}
int main(int argc, char **argv)
{

	char *exe_name = get_exe_name(argv[0]);
	if(consumer_is_running(exe_name)){
		printf("consumer process is already running\n");
		return 0;
	}
	consumer_daemo();
	int i = 0;
	struct MESA_shm_overview *shm_overview = NULL;
	struct MESA_shm_overview *tmp_ovw = NULL;
	struct MESA_shm_queue_head *ring_queue_head[MESA_SHM_RING_QUEUE_NUM] = {NULL};
	int log_file_fd = -1;
	shm_overview = MESA_shm_alloc_overview();
	if(shm_overview == NULL){
		return 0;
	}
	init_ring_queue_head_arrray(shm_overview, ring_queue_head);
	log_file_fd = open("/root/MESA_log", O_RDWR | O_CREAT | O_APPEND, 0666);
	if(log_file_fd < 0){
		return 0;
	}
	while(1){
		for(i = 0; i< MESA_SHM_RING_QUEUE_NUM; i++){
			tmp_ovw = shm_overview + i;
			if(tmp_ovw->shmid == -1){
				break;
			}
			if(ring_queue_head[i] == NULL){
				ring_queue_head[i] = shmat(tmp_ovw->shmid, NULL, 0);
				if(ring_queue_head[i] == NULL){
					break ;
				}
			}
			if(tmp_ovw->status == MESA_SHM_RING_QUEUE_USED || tmp_ovw->status == MESA_SHM_RING_QUEUE_HALF_IDLE){
				MESA_shm_write_ring_queue_to_file(log_file_fd, ring_queue_head[i]);
				if(tmp_ovw->status == MESA_SHM_RING_QUEUE_HALF_IDLE){
					tmp_ovw->status = MESA_SHM_RING_QUEUE_IDLE;
				}
			}
		}
		usleep(5000);
	}	
	return 0;
}