#define _XOPEN_SOURCE 700
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>

#define osAssert(state, msg) osErrorFatal(state, msg, __LINE__, __FILE__)

void osErrorFatal(bool state, const char *msg, int lineNum, const char *fname){
    if(!state){
        perror(msg);
        fprintf(stderr, "%s:%d\n",fname, lineNum);
        exit(EXIT_FAILURE);
    }
}

int osCalculateFolderSize(char *path, unsigned *size){
    DIR *dirFD= opendir(path);
    if(dirFD == NULL){
        return false;
    }
    struct dirent *folder;
    struct stat buf;
    while((folder=readdir(dirFD))!=NULL){
        //printf("%s\n", folder->d_name);
        // const char *pathname, struct stat *buf
        // *;

        if(strcmp(".",folder->d_name) || strcmp("..",folder->d_name)){
                continue;
        } else {
            char* newPath = strndup(path, strlen(path)+1+strlen(folder->d_name));
            strcat(newPath, "/");
            strcat(newPath, folder->d_name);
            printf("p: %s\n", newPath);
            osAssert(-1!=lstat(newPath, &buf),"lstat failed inwhile");

            if(S_ISDIR(buf.st_mode)){
                osAssert(-1!=osCalculateFolderSize(newPath, size),"failed to calculate dir size");
            } else {
                *size += buf.st_size;
            }


        }
    }
    return 0;
}

int main(int argc, char **argv){
    osAssert(2==argc,"wrong num of args");
    struct stat buf;
    osAssert(-1!=lstat(argv[1],&buf),"stat failed");
    osAssert(S_ISDIR(buf.st_mode), "this is not dir");
    unsigned size = 0;
    osAssert(-1!=osCalculateFolderSize(argv[1], &size),"failed to calculate dir size");
    printf("\n");
    printf("size: %u\n",size);
    return 0;
}