#include <stdio.h>
#include <dirent.h>
#include <time.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>

#define MAX_PATH_LEN 1023
#define MAX_DIRECTORY_BRANCH 1000

/* Don't know about MacOS... */
#ifdef __unix__
    #define SEPARATOR_CHAR '/'
#else
    #define SEPARATOR_CHAR '\\' 
#endif

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

    if( argc == 1 )
    {
        int totalSize = processDir( "." );
        printf( "Total size for . is %d\n", totalSize );
    }
    else
        for( i = 1; i < argc; i++ )
        {
            int size = processDir( argv[ i ] );
            printf( "Total size for %s is %d\n", argv[ i ], size );
        }
    
    return 0;
}

/*
 * Return total size of all files
 */
int processDir( const char *dirName )
{
    DIR *dp;
    struct dirent *slot;
    struct stat buf;
    char *timeRep;
    int isDir;
    char fullName[ MAX_PATH_LEN + 1 ];
    int numSubDirectories = 0;
    char *subdirectories[ MAX_DIRECTORY_BRANCH ];
    int i;
    int totalSize = 0;

    printf( "DIRECTORY %s\n", dirName );

    if( ( dp = opendir( dirName ) ) == NULL )
    {
        fprintf( stderr, "Error opening directory\n" );
        return 0;
    }

    for( slot = readdir( dp ); slot != NULL; slot = readdir( dp ) )
    {
        sprintf( fullName, "%s%c%s", dirName, SEPARATOR_CHAR, slot->d_name );

        if( stat( fullName, &buf ) == -1 )
        {
            fprintf( stderr, "Error statting %s\n", fullName );
            continue;
        }
        
        timeRep = ctime( (time_t *) &buf.st_mtim );
        timeRep[ 24 ] = '\0';

        printf( "%s ", timeRep );

        totalSize += buf.st_size;

        isDir = ( buf.st_mode & S_IFMT ) == S_IFDIR;

        if( isDir )
            printf( " (DIR) " );
        else
            printf( "       " );
        
        printf( "%12d ", buf.st_size );
        printf( "%s", slot->d_name );
        
        printf( "\n" );

        if( isDir && strcmp( slot->d_name, "." ) != 0
                  && strcmp( slot->d_name, ".." ) != 0 )
        {
            if( numSubDirectories == MAX_DIRECTORY_BRANCH )
                fprintf( stderr, "Directory branching limit exceeded\n" );
            else
                subdirectories[ numSubDirectories++ ] = strdup( fullName );
        }
    }

    printf( "\n" );

    for( i = 0; i < numSubDirectories; i++ )
    {
        totalSize += processDir( subdirectories[ i ] );
        free( subdirectories[ i ] );
    }
    closedir( dp );

    return totalSize;
}