#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#define DEVICE_PATH "/dev/led"



void usage()
{
    printf("Usage: [command] [param1] [param2] [param2]\n");
    printf("Commands:\n");
    printf("  setled off\n");
    printf("  setled red off\n");
    printf("  setled green off\n");
    printf("  setled red on 1\n");
    printf("  setled green on 255\n");
}

int main(int argc, char *argv[])
{
    int fd = 0;
    int ret = 0;
    int blink_value = 0;
    char buff[3];
    if (argc == 2)
    {
        if(strcmp(argv[1], "off") == 0)
        {
            buff[0] = 0x00;
            buff[1] = 0x01;
            buff[2] = 0x01;
        }
    }
    else if (argc == 3)
    {
        if(strcmp(argv[1], "red") == 0)
        {
            buff[0] = 0x40;
        }
        else if(strcmp(argv[1], "green") == 0)
        {
            buff[0] = 0x80;
        }
        else
        {
            usage();
            return -1;
        }

        if(strcmp(argv[2], "off") == 0)
        {
            buff[1] = 0x00;
            buff[2] = 0x01;
        }
        else
        {
            usage();
            return -1;
        }
    }
    else if (argc == 4)
    {
        if(strcmp(argv[1], "red") == 0)
        {
            buff[0] = 0x40;
        }
        else if(strcmp(argv[1], "green") == 0)
        {
            buff[0] = 0x80;
        }
        else
        {
            usage();
            return -1;
        }

        if(strcmp(argv[2], "on") == 0)
        {
            buff[1] = 0x01;
        }
        else
        {
            usage();
            return -1;
        }

        blink_value = atoi(argv[3]);
        buff[2] = blink_value&0xff;
    }
    else
    {
        usage();
        return -1;
    }

    fd = open(DEVICE_PATH, O_RDWR);
    if (fd < 0)
    {
        perror("open failed");
        return -1;
    }

    ret = write(fd, buff, sizeof(buff));
    if (ret < 0)
    {
        perror("write failed");
        close(fd);
        return -1;
    }

    close(fd);
    return 0;
}