//--------------------------------------------
// NAME:Konstantin Georgiev
// CLASS:XIa
// NUMBER:15
// PROBLEM:#1
// FILE NAME:m.c
// FILE PURPOSE: ls unix function implementation in C
//---------------------------------------------
#include<stdio.h>
#include<dirent.h>
#include<stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
//--------------------------------------------
// FUNCTION: printNormalContents
// prints a directory's contents
// PARAMETERS:
// char *thing - The name of the directory to be opened
// int hidden - a flag that tells the function if it needs to display hidden files
// int isDirectory - a flag that tells the function if it needs to print the directory name
//--------------------------------------------
void printNormalContents(char *thing, int hidden, int isDirectory, int isDetailed){
    if(isDirectory != 1){
        printf("%s:\n", thing);
    }
    DIR*p;
    struct dirent *d;
    p = opendir(thing);
    if(p == NULL){
        fprintf(stderr, "ls: cannot access %s: No such file or directory", thing);
    return;
    }
    while(d=readdir(p)){
    if(d->d_name[0] != '.' || hidden == 1){
    struct stat path_stat;
    stat(d->d_name, &path_stat);
    if(isDetailed == 1){
        if(S_IRUSR(path_stat.st_mode)){printf(" r");}
        else{printf(" -");}
        if(S_IWUSR(path_stat.st_mode)){printf("w");}
        else{printf("-");}
        if(S_IXUSR(path_stat.st_mode)){printf("x");}
        else{printf("-");}
        if(S_IRGRP(path_stat.st_mode)){printf("r");}
        else{printf("-");}
        if(S_IWGRP(path_stat.st_mode)){printf("w");}
        else{printf("-");}
        if(S_IXGRP(path_stat.st_mode)){printf("x");}
        else{printf("-");}
        if(S_IROTH(path_stat.st_mode)){printf("r");}
        else{printf("-");}
        if(S_IWOTH(path_stat.st_mode)){printf("w");}
        else{printf("-");}
        if(S_IXOTH(path_stat.st_mode)){printf("x");}
        else{printf("-");}
        printf("\t%d ", path_stat.st_nlink);
        printf("\t%s ", getpwuid(path_stat.st_uid)->pw_name);
        printf("\t%s ", getgrgid(path_stat.st_gid)->gr_name);
        printf("%zu", path_stat.st_size);
        if(S_ISREG(path_stat.st_mode)){ //Checking if regular file
        printf(" %s",d->d_name);}
        else if(S_ISDIR(path_stat.st_mode)){ //Checking if directory
            printf(" %s",d->d_name);}
        else if(S_ISCHR(path_stat.st_mode)){ //Checking if character device
            printf(" %s",d->d_name);}
        else if(S_ISBLK(path_stat.st_mode)){ //Checking if block device
            printf(" %s",d->d_name);}
        else if(S_ISFIFO(path_stat.st_mode)){ //Checking if program stream
            printf(" %s",d->d_name);}
        else if(S_ISLNK(path_stat.st_mode)){
            printf(" %s",d->d_name);}
        else if(S_ISSOCK(path_stat.st_mode)){ //Checking if socket
            printf(" %s",d->d_name);}
        printf(" %s\n", ctime(&path_stat.st_mtime));
    }
    else{
    if(S_ISREG(path_stat.st_mode)){ //Checking if regular file
        printf("- %s\n",d->d_name);}
    else if(S_ISDIR(path_stat.st_mode)){ //Checking if directory
        printf("d %s\n",d->d_name);}
    else if(S_ISCHR(path_stat.st_mode)){ //Checking if character device
        printf("c %s\n",d->d_name);}
    else if(S_ISBLK(path_stat.st_mode)){ //Checking if block device
        printf("b %s\n",d->d_name);}
    else if(S_ISFIFO(path_stat.st_mode)){ //Checking if program stream
        printf("p %s\n",d->d_name);}
    else if(S_ISLNK(path_stat.st_mode)){
        printf("l %s\n",d->d_name);}
    else if(S_ISSOCK(path_stat.st_mode)){ //Checking if socket
        printf("s %s\n",d->d_name);}}
}
}
	closedir(p);
}
int main(int argc, char **argv){
    int hidden = 0;
    int flag = 0;
    int dirFlag = 0;
    if(argc > 1){
        if(argc == 2){dirFlag = 1;}
        if(argv[1][0] == '.'){printNormalContents("./", hidden, 1);
            return;}
        for(int i = 1; i < argc; i++){
            if(strstr(argv[i], "-") != NULL && (strstr(argv[i], "a") != NULL || strstr(argv[i], "A") != NULL) ){hidden = 1;
            }
        }
        for(int i = 1; i < argc; i++){
            if(strstr(argv[i], "-") == NULL){
                if(strstr(argv[i], "/") == NULL){
                    if(strstr(argv[i], ".") != NULL && argv[i][0] != '.'){
                        if(access(argv[i], F_OK) != -1){
                            printf("- %s\n", argv[i]);
                        }
                        else{
                            fprintf(stderr, "ls: cannot access %s: No such file or directory", argv[i]);
                        }
                    }
                    else{
                    printNormalContents(argv[i], hidden, dirFlag);
			if(i != argc - 1 && argv[i+1][0] != '.'){printf("\n");}
                    }
                }
                else{
                    printNormalContents(argv[i], hidden, dirFlag);
			if(i != argc - 1 && argv[i+1][0] != '.'){printf("\n");}
                }
                flag = 1;
            }
        }
        if(flag == 0){
            printNormalContents("./", hidden, 1);
        }
    }
    else{
        printNormalContents("./", hidden, 1);
        }
}