#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#ifndef WIN32
#include <unistd.h>
#include <getopt.h>
#else
#include <io.h>
#include "win/getopt/getopt.h"
#endif

#define MAX_FNAME 128

struct flist {
	char filename[MAX_FNAME];
	struct flist *next;
};

static int add_flist(struct flist **f, const char *filename)
{
	struct flist *p, *c;
	c = malloc(sizeof(*c));
	if (!c)
		return -1;
	strcpy(c->filename, filename);
	c->next = NULL;
	if (!(*f)) {
		*f = c;
		return 0;
	}
	for (p=*f;p->next;p=p->next)
		;
	p->next = c;
	return 0;
}

struct option longopts[] = {
	{ "minsize",	required_argument, 0, 'm' },
	{ "maxsize",	required_argument, 0, 'M' },
	{ "maxfiles",	required_argument, 0, 'f' },
	{ "seed",		required_argument, 0, 's' },
	{ NULL, 0, 0, 0 }
};

#define DEFAULT_MINSIZE 0
#define DEFAULT_MAXSIZE (128 * 1024)

int main(int argc, char **argv)
{
	struct flist *f = NULL, *p, *prev;
	char *buffer;
	int c, count;
	int i;
	int err;

	int minsize = DEFAULT_MINSIZE, maxsize = DEFAULT_MAXSIZE, maxfiles = 0;
	int seed = time(0)|1;

	while ((c = getopt_long(argc, argv, "f:s:m:M:", longopts, NULL)) != EOF) {
		switch (c) {
			case 'm' : minsize = strtol(optarg,0,0); break;
			case 'M' : maxsize = strtol(optarg,0,0); break;
			case 's' : seed = strtol(optarg,0,0); break;
			case 'f' : maxfiles = strtol(optarg,0,0); break;
			case '?' :
				printf("arguments:\n"
					"  --minsize|-m <bytes> -- minimum file size to create (default %d)\n"
					"  --maxsize|-M <bytes> -- maximum file size to create (default %d)\n"
					"  --maxfiles|-f <files> -- limit the maximum number of files to create\n"
					"  --seed|-s <value> -- random number seed to use\n",
					DEFAULT_MINSIZE, DEFAULT_MAXSIZE);
				return 1;
		}
	}

	if (optind != argc) {
		printf("Extra arguments found. Aborting.\n");
		return 1;
	}

	if (maxsize < minsize) {
		printf("Maximum file size (0x%x) < Minimum file size (0x%x)!\n",
				maxsize, minsize);
		return 1;
	}

	buffer = calloc(maxsize, 1);
	if (!buffer) {
		printf("Out of memory allocating write buffer\n");
		return 1;
	}

	srand(seed);

	printf("Seed = 0x%x, minsize = %d, maxsize = %d, ",
				seed, minsize, maxsize);
	if (maxfiles)
		printf("maxfiles = %d\n", maxfiles);
	else
		printf("no maxfiles\n");

	while(1) {

		printf("Creating files\n");
		count = 0;
		while ((maxfiles == 0) || (count < maxfiles)) {
			char fname[MAX_FNAME];
			int fd;
			int size;

			sprintf(fname, "f%8.8x.%8.8x", rand(), rand());
			fd = open(fname, O_RDWR | O_CREAT, 0666);
			if (fd < 0)
				break;
			printf("Created file '%s'\n", fname);
#ifdef WIN32
			size = (((int)rand() + ((int)rand() << 16)) % (maxsize - minsize + 1)) + minsize;
#else
			size = rand() % (maxsize - minsize + 1) + minsize;
#endif
			for(i=0; i<size; i++) {
				if((rand() % 100) >= 75) buffer[i] = rand();
				else buffer[i] = 0;
			}
			err = write(fd, buffer, size);
			close(fd);
			if(err < 0) {
				printf("err writing to file, unlinking it\n");
				unlink(fname);
				break;
			}

			if (add_flist(&f, fname) < 0) {
				printf("Error adding filename to list (Out of memory?)\n");
				return 1;
			}

			if ((++count % 100) == 0) {
				printf("%d files created\r", count); fflush(stdout);
			}
		}

		printf("%d files created. Deleting 50%% of files.\n", count);

		prev = NULL;
		p = f;
		count = 0;
		while (p) {
			if((rand() % 100) >= 50) {
				unlink(p->filename);
				printf("Unlinked file '%s'\n", p->filename);
				if ((++count % 100) == 0) {
					printf("%d files deleted\r", count); fflush(stdout);
				}
				if(prev == NULL) {
					f = p->next;
					free(p);
					p = f;
				} else {
					prev->next = p->next;
					free(p);
					p = prev->next;
				}
			} else {
				prev = p;
				p = p->next;
			}
		}
	}

	free(buffer);

	printf("done\n");

	return 0;
}