#include "utils.h"
#include "xmalloc.h"

#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>

extern char *program_name;

static int copy_file(const char *src, const char *dst)
{
	int src_fd, dst_fd;
	struct stat st;
	int save;

	src_fd = open(src, O_RDONLY);
	if (src_fd == -1)
		return -1;
	fstat(src_fd, &st);
	dst_fd = creat(dst, st.st_mode);
	if (dst_fd == -1) {
		save = errno;
		close(src_fd);
		errno = save;
		return -1;
	}
	do {
		char buffer[8192];
		int rcount, wcount;
		char *ptr;

		rcount = read(src_fd, buffer, sizeof(buffer));
		if (rcount == -1)
			goto err_exit;
		if (rcount == 0) {
			close(dst_fd);
			close(src_fd);
			return 0;
		}
		ptr = buffer;
		do {
			wcount = write(dst_fd, ptr, rcount);
			if (wcount == -1)
				goto err_exit;
			rcount -= wcount;
			ptr += wcount;
		} while (rcount > 0);
	} while (1);
err_exit:
	save = errno;
	unlink(dst);
	close(dst_fd);
	close(src_fd);
	errno = save;
	return -1;
}

int move_file(const char *src, const char *dst)
{
	int rc;

	rc = rename(src, dst);
	if (rc == -1) {
		if (errno != EXDEV) {
			return -1;
		}
		if (copy_file(src, dst) == -1)
			return -1;
		if (unlink(src) == -1) {
			int save;

			/* grrr... have to remove file we just copied */
			save = errno;
			if (unlink(dst) == -1) {
			}
			errno = save;
			return -1;
		}
	}
	return 0;
}

int mkpath(const char *filename)
{
	char cwd[1024];
	char *str, *s, *e;
	int rc = 0;

	if (getcwd(cwd, sizeof(cwd)) == NULL) {
		/* fatal error */
		return -1;
	}
	str = xstrdup(filename);
	s = str;
	if (*s == '/') {
		if (chdir("/") == -1) {
			rc = -1;
			goto out;
		}
		s++;
	}
	while ((e = strchr(s, '/')) != NULL) {
		struct stat st;

		*e = 0;
		e++;
		if (stat(s, &st) == -1) {
			if (errno != ENOENT) {
				/* permission denied */
				rc = -1;
				break;
			}
			/* file does not exist */
			if (mkdir(s, 0777) == -1) {
				rc = -1;
				break;
			}
		}
		if (chdir(s) == -1) {
			rc = -1;
			break;
		}
		s = e;
	}
out:
	if (chdir(cwd) == -1) {
		/* fatal error */
		rc = -1;
	}
	free(str);
	return rc;
}

static void strip_slashes(char *filename)
{
	int s, d, slash;

	s = -1;
	d = 0;
	slash = 0;
	do {
		s++;
		if (filename[s] == '/') {
			if (!slash) {
				slash = 1;
				filename[d++] = filename[s];
			}
		} else {
			slash = 0;
			filename[d++] = filename[s];
		}
	} while (filename[s]);
}

int rename_file(const char *filename, const char *destination)
{
	char *new_filename;
	struct stat st;
	int rc;

	new_filename = xstrdup(destination);
	strip_slashes(new_filename);
	rc = stat(filename, &st);
	if (rc == -1) {
		if (errno != ENOENT) {
			fprintf(stderr, "%s: error: can't stat() `%s': %s\n",
					program_name, new_filename,
					strerror(errno));
			free(new_filename);
			return -1;
		}
	} else if (rc) {
		fprintf(stderr, "%s: file `%s' already exists\n",
				program_name, new_filename);
		free(new_filename);
		return -1;
	}
	if (mkpath(new_filename)) {
		fprintf(stderr, "%s: can't create directory componets for `%s': %s\n",
				program_name, new_filename,
				strerror(errno));
		free(new_filename);
		return -1;
	}
	if (move_file(filename, new_filename) == -1) {
		fprintf(stderr, "%s: can't rename file `%s' to `%s': %s\n",
				program_name, filename,
				new_filename, strerror(errno));
		free(new_filename);
		return -1;
	}
	return 0;
}