/*********************************************************************************
 *      Copyright:  (C) 2023 LingYun IoT System Studio.
 *                  All rights reserved.
 *
 *       Filename:  mycp.c
 *    Description:  This file is ls command example code.
 *
 *        Version:  1.0.0(2023年08月08日)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2023年08月08日 17时17分00秒"
 *
 ********************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <dirent.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <sys/types.h>
#include <sys/stat.h>

#define PROGNAME        "myls"

static int myls(char *path);

int main (int argc, char **argv)
{
    int           fd;
    int           i;

    if( 1 == argc )
    {
        myls(".");
        return 0;
    }

    for(i=1; i<argc; i++)
    {
        myls(argv[i]);
    }

    return 0;
}

void print_filemode(mode_t mode)
{
    /* print file type */
    if( S_ISREG(mode) )
    {
        printf("-");
    }
    else if( S_ISDIR(mode) )
    {
        printf("d");
    }
    else if( S_ISCHR(mode) )
    {
        printf("c");
    }
    else if( S_ISBLK(mode) )
    {
        printf("b");
    }
    else if( S_ISFIFO(mode) )
    {
        printf("f");
    }
    else if( S_ISLNK(mode) )
    {
        printf("l");
    }
    else if( S_ISSOCK(mode) )
    {
        printf("s");
    }

    /* print file mode  */
    printf("%c", (S_IRUSR&mode) ? 'r' : '-');
    printf("%c", (S_IWUSR&mode) ? 'w' : '-');
    printf("%c", (S_IXUSR&mode) ? 'x' : '-');

    printf("%c", (S_IRGRP&mode) ? 'r' : '-');
    printf("%c", (S_IWGRP&mode) ? 'w' : '-');
    printf("%c", (S_IXGRP&mode) ? 'x' : '-');

    printf("%c", (S_IROTH&mode) ? 'r' : '-');
    printf("%c", (S_IWOTH&mode) ? 'w' : '-');
    printf("%c", (S_IXOTH&mode) ? 'x' : '-');

    printf(" ");

    return ;
}

int print_info(char *file)
{
    struct stat   sbuf;
    struct passwd *u;
    struct group  *g;
    time_t         t;
    struct tm     *ptm;
    char           mtime[32];

    stat(file, &sbuf);

    print_filemode(sbuf.st_mode);

    /* print number of hard links  */
    printf("%2lu ", sbuf.st_nlink);

    /* print user name or user id */
    u = getpwuid (sbuf.st_uid);
    if( u )
        printf("%s ", u->pw_name);
    else
        printf("%d ", sbuf.st_uid);

    /* print group name or group id */
    g = getgrgid (sbuf.st_gid);
    if( g )
        printf("%s ", g->gr_name);
    else
        printf("%d ", sbuf.st_uid);

    /* print file size  */
    printf("%6lu ", sbuf.st_size);

    /* print time of last modification, Time functions:
     *    https://www.jianshu.com/p/e92ced44f216
     *    https://blog.csdn.net/chen1415886044/article/details/106883544
     */
    t = (time_t)sbuf.st_mtim.tv_sec;
    ptm = localtime(&t);
    strftime(mtime, sizeof(mtime), "%b %e %R", ptm);
    printf("%s ", mtime);

    printf("%s", file);

    printf("\n");

    return 0;
}

int myls(char *path)
{
    struct stat    sbuf;
    DIR           *dirp;
    struct dirent *dir;
    char           filepath[512];

    /* Check file exist or not */
    if( access(path, F_OK) )
    {
        printf("%s: cannot access '%s': %s\n", PROGNAME, path, strerror(errno));
        return -2;
    }

    stat(path, &sbuf);

    /* list file */
    if( !S_ISDIR(sbuf.st_mode) )
    {
        print_info(path);
        return 0;
    }

    /* list folder */
    dirp = opendir(path);
    if( !dirp )
    {
        printf("%s: cannot open directory '%s': %s\n", PROGNAME, path, strerror(errno));
        return -3;
    }

    while( NULL != (dir=readdir(dirp)) )
    {
        if( !strcmp(path, ".") )
            strncpy(filepath, dir->d_name, sizeof(filepath));
        else
            snprintf(filepath, sizeof(filepath), "%s/%s", path, dir->d_name);

        print_info(filepath);
    }

    return 0;
}