/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */


// Re-enable some forbidden symbols to avoid clashes with stat.h and unistd.h.
// Also with clock() in sys/time.h in some Mac OS X SDKs.
#define FORBIDDEN_SYMBOL_EXCEPTION_time_h	//On IRIX, sys/stat.h includes sys/time.h
#define FORBIDDEN_SYMBOL_EXCEPTION_unistd_h
#define FORBIDDEN_SYMBOL_EXCEPTION_mkdir
#define FORBIDDEN_SYMBOL_EXCEPTION_getenv
// OpenVMS: the __VMS branch of the constructor below registers the current
// working directory as the savepath, so it needs the real getcwd().  (It comes
// from <unistd.h>, which the FORBIDDEN_SYMBOL_EXCEPTION_unistd_h above lets us
// include; that exception does NOT re-enable getcwd itself.)
#define FORBIDDEN_SYMBOL_EXCEPTION_getcwd

#include "common/scummsys.h"

#if defined(POSIX) && !defined(DISABLE_DEFAULT_SAVEFILEMANAGER)

#include "backends/saves/posix/posix-saves.h"
#include "backends/fs/posix/posix-fs.h"

#include "common/config-manager.h"
#include "common/savefile.h"
#include "common/textconsole.h"

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

POSIXSaveFileManager::POSIXSaveFileManager() {
	// Register default savepath.
#if defined(__VMS)
	// OpenVMS: saves ALWAYS go to the current directory ("[]").
	//
	// This is a run-from-the-game-data-directory port (see autodetectCurrentDir()
	// in base/main.cpp), and VMS has neither HOME nor XDG_DATA_HOME, so the POSIX
	// heuristics in the #else branch below produce NOTHING: savePath stays empty,
	// Posix::assureDirectoryExists() fails on its stat("") of the empty prefix,
	// and registerDefault("savepath", ...) is never reached at all.
	//
	// getSavePath() (default-saves.cpp) then returns "", and Common::FSNode's
	// String constructor silently maps "" to the current working directory
	// (common/fs.cpp:42).  So saves did land here anyway - but only by accident,
	// via a path nothing in the program could report, and every consumer that
	// reads ConfMan.get("savepath") directly (the debugger's "save_original"
	// command, EoBCoreEngine::saveAsOriginalSaveFile) saw an empty string.
	// Register the current directory EXPLICITLY instead.
	//
	// --savepath is not a usable workaround on this platform: it takes a POSIX
	// path, not a VMS filespec.  Nothing here needs one now.
	{
		char cwd[MAXPATHLEN];
		// DECC$FILENAME_UNIX_REPORT is enabled by RUNSETUP.COM, so this is a
		// '/'-separated path, which is what the rest of the file layer wants.
		if (getcwd(cwd, sizeof(cwd)) != NULL && *cwd)
			ConfMan.registerDefault("savepath", Common::String(cwd));
		else
			ConfMan.registerDefault("savepath", ".");

		// Say it out loud.  Saves were going to an unreported location before
		// (getSavePath() returned "" and FSNode mapped that to the cwd behind the
		// scenes), which is precisely why "where do the saves go" was unanswerable
		// from a run.  One line at startup makes it answerable.  warning() rather
		// than printf(), which is a forbidden symbol here, or debug(), which needs
		// -d on the command line to appear.
		warning("Kyra/VMS: savepath = '%s'", ConfMan.get("savepath").c_str());
	}
#elif defined(SAMSUNGTV)
	ConfMan.registerDefault("savepath", "/mtd_wiselink/scummvm savegames");
#else
	Common::String savePath;

#if defined(MACOSX)
	const char *home = getenv("HOME");
	if (home && *home && strlen(home) < MAXPATHLEN) {
		savePath = home;
		savePath += "/Documents/ScummVM Savegames";

		ConfMan.registerDefault("savepath", savePath);
	}

#else
	const char *envVar;

	// Previously we placed our default savepath in HOME. If the directory
	// still exists, we will use it for backwards compatability.
	envVar = getenv("HOME");
	if (envVar && *envVar) {
		savePath = envVar;
		savePath += "/.scummvm";

		struct stat sb;
		if (stat(savePath.c_str(), &sb) != 0 || !S_ISDIR(sb.st_mode)) {
			savePath.clear();
		}
	}

	if (savePath.empty()) {
		Common::String prefix;

		// On POSIX systems we follow the XDG Base Directory Specification for
		// where to store files. The version we based our code upon can be found
		// over here: http://standards.freedesktop.org/basedir-spec/basedir-spec-0.8.html
		envVar = getenv("XDG_DATA_HOME");
		if (!envVar || !*envVar) {
			envVar = getenv("HOME");
			if (envVar && *envVar) {
				prefix = envVar;
				savePath = ".local/share/";
			}
		} else {
			prefix = envVar;
		}

		// Our default save path is '$XDG_DATA_HOME/scummvm/saves'
		savePath += "scummvm/saves";

		if (!Posix::assureDirectoryExists(savePath, prefix.c_str())) {
			savePath.clear();
		} else {
			savePath = prefix + '/' + savePath;
		}
	}

	if (!savePath.empty() && savePath.size() < MAXPATHLEN) {
		ConfMan.registerDefault("savepath", savePath);
	}
#endif

	// The user can override the savepath with the SCUMMVM_SAVEPATH
	// environment variable. This is weaker than a --savepath on the
	// command line, but overrides the default savepath.
	//
	// To ensure that the command line option (if given) has precedence,
	// we only set the value in the transient domain if it is not
	// yet present there.
	if (!ConfMan.hasKey("savepath", Common::ConfigManager::kTransientDomain)) {
		const char *dir = getenv("SCUMMVM_SAVEPATH");
		if (dir && *dir && strlen(dir) < MAXPATHLEN) {
			Common::FSNode saveDir(dir);
			if (!saveDir.exists()) {
				warning("Ignoring non-existent SCUMMVM_SAVEPATH '%s'", dir);
			} else if (!saveDir.isWritable()) {
				warning("Ignoring non-writable SCUMMVM_SAVEPATH '%s'", dir);
			} else {
				ConfMan.set("savepath", dir, Common::ConfigManager::kTransientDomain);
			}
		}
	}
#endif
}

void POSIXSaveFileManager::checkPath(const Common::FSNode &dir) {
	const Common::String path = dir.getPath();
	clearError();

	struct stat sb;

	// Check whether the dir exists
	if (stat(path.c_str(), &sb) == -1) {
		// The dir does not exist, or stat failed for some other reason.
		// If the problem was that the path pointed to nothing, try
		// to create the dir (ENOENT case).
		switch (errno) {
		case EACCES:
			setError(Common::kWritePermissionDenied, "Search or write permission denied: "+path);
			break;
		case ELOOP:
			setError(Common::kUnknownError, "Too many symbolic links encountered while traversing the path: "+path);
			break;
		case ENAMETOOLONG:
			setError(Common::kUnknownError, "The path name is too long: "+path);
			break;
		case ENOENT:
			if (mkdir(path.c_str(), 0755) != 0) {
				// mkdir could fail for various reasons: The parent dir doesn't exist,
				// or is not writeable, the path could be completly bogus, etc.
				warning("mkdir for '%s' failed", path.c_str());
				perror("mkdir");

				switch (errno) {
				case EACCES:
					setError(Common::kWritePermissionDenied, "Search or write permission denied: "+path);
					break;
				case EMLINK:
					setError(Common::kUnknownError, "The link count of the parent directory would exceed {LINK_MAX}: "+path);
					break;
				case ELOOP:
					setError(Common::kUnknownError, "Too many symbolic links encountered while traversing the path: "+path);
					break;
				case ENAMETOOLONG:
					setError(Common::kUnknownError, "The path name is too long: "+path);
					break;
				case ENOENT:
					setError(Common::kPathDoesNotExist, "A component of the path does not exist, or the path is an empty string: "+path);
					break;
				case ENOTDIR:
					setError(Common::kPathDoesNotExist, "A component of the path prefix is not a directory: "+path);
					break;
				case EROFS:
					setError(Common::kWritePermissionDenied, "The parent directory resides on a read-only file system:"+path);
					break;
				}
			}
			break;
		case ENOTDIR:
			setError(Common::kPathDoesNotExist, "A component of the path prefix is not a directory: "+path);
			break;
		}
	} else {
		// So stat() succeeded. But is the path actually pointing to a directory?
		if (!S_ISDIR(sb.st_mode)) {
			setError(Common::kPathDoesNotExist, "The given savepath is not a directory: "+path);
		}
	}
}

#endif
