#ifndef DAT_PATHS_H
#define DAT_PATHS_H

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef _WIN32
#include <windows.h>
#endif

/* Return the user's home directory across POSIX shells and native Windows
 * launches. Windows GUI starts commonly have USERPROFILE but no HOME. */
static inline const char *dat_home_directory(void)
{
	const char *home = getenv("HOME");
	if (home && *home) return home;
#ifdef _WIN32
	home = getenv("USERPROFILE");
	if (home && *home) return home;
	{
		const char *drive = getenv("HOMEDRIVE");
		const char *path = getenv("HOMEPATH");
		static char combined[1024];
		int n;
		if (!drive || !*drive || !path || !*path) return NULL;
		n = snprintf(combined, sizeof(combined), "%s%s", drive, path);
		return n >= 0 && (size_t)n < sizeof(combined) ? combined : NULL;
	}
#else
	return NULL;
#endif
}

/* POSIX rename replaces an existing file; Windows rename does not. These
 * state files are written to a sibling temporary file before replacement. */
static inline int dat_replace_file(const char *temporary, const char *destination)
{
#ifdef _WIN32
	if (MoveFileExA(temporary, destination,
			MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)) return 0;
	errno = EIO;
	return -1;
#else
	return rename(temporary, destination);
#endif
}

#endif