/**
	@author Martín Lucas Golini

	Copyright (c) 2013 Martín Lucas Golini

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	THE SOFTWARE.

	This software is a fork of the "simplefilewatcher" by James Wynn (james@jameswynn.com)
	http://code.google.com/p/simplefilewatcher/ also MIT licensed.
*/

#ifndef ESFW_HPP
#define ESFW_HPP

#include <list>
#include <string>

#if defined( _WIN32 )
#ifdef EFSW_DYNAMIC
// Windows platforms
#ifdef EFSW_EXPORTS
// From DLL side, we must export
#define EFSW_API __declspec( dllexport )
#else
// From client application side, we must import
#define EFSW_API __declspec( dllimport )
#endif
#else
// No specific directive needed for static build
#ifndef EFSW_API
#define EFSW_API
#endif
#endif
#else
#if ( __GNUC__ >= 4 ) && defined( EFSW_EXPORTS )
#ifndef EFSW_API
#define EFSW_API __attribute__( ( visibility( "default" ) ) )
#endif
#endif

// Other platforms don't need to define anything
#ifndef EFSW_API
#define EFSW_API
#endif
#endif

namespace efsw {

/// Type for a watch id
typedef long WatchID;

// forward declarations
class FileWatcherImpl;
class FileWatchListener;

/// Actions to listen for. Rename will send two events, one for
/// the deletion of the old file, and one for the creation of the
/// new file.
namespace Actions {
enum Action {
	/// Sent when a file is created or renamed
	Add = 1,
	/// Sent when a file is deleted or renamed
	Delete = 2,
	/// Sent when a file is modified
	Modified = 3,
	/// Sent when a file is moved
	Moved = 4
};
}
typedef Actions::Action Action;

/// Errors log namespace
namespace Errors {

enum Error {
	FileNotFound = -1,
	FileRepeated = -2,
	FileOutOfScope = -3,
	FileNotReadable = -4,
	FileRemote = -5, /** Directory in remote file system ( create a generic FileWatcher instance to
						watch this directory ). */
	Unspecified = -6
};

class EFSW_API Log {
  public:
	/// @return The last error logged
	static std::string getLastErrorLog();

	/// Creates an error of the type specified
	static Error createLastError( Error err, std::string log );
};

} // namespace Errors
typedef Errors::Error Error;

/// Listens to files and directories and dispatches events
/// to notify the listener of files and directories changes.
/// @class FileWatcher
class EFSW_API FileWatcher {
  public:
	/// Default constructor, will use the default platform file watcher
	FileWatcher();

	/// Constructor that lets you force the use of the Generic File Watcher
	explicit FileWatcher( bool useGenericFileWatcher );

	virtual ~FileWatcher();

	/// Add a directory watch. Same as the other addWatch, but doesn't have recursive option.
	/// For backwards compatibility.
	/// On error returns WatchID with Error type.
	WatchID addWatch( const std::string& directory, FileWatchListener* watcher );

	/// Add a directory watch
	/// On error returns WatchID with Error type.
	WatchID addWatch( const std::string& directory, FileWatchListener* watcher, bool recursive );

	/// Remove a directory watch. This is a brute force search O(nlogn).
	void removeWatch( const std::string& directory );

	/// Remove a directory watch. This is a map lookup O(logn).
	void removeWatch( WatchID watchid );

	/// Starts watching ( in other thread )
	void watch();

	/// @return Returns a list of the directories that are being watched
	std::list<std::string> directories();

	/** Allow recursive watchers to follow symbolic links to other directories
	 * followSymlinks is disabled by default
	 */
	void followSymlinks( bool follow );

	/** @return If can follow symbolic links to directorioes */
	const bool& followSymlinks() const;

	/** When enable this it will allow symlinks to watch recursively out of the pointed directory.
	 * follorSymlinks must be enabled to this work.
	 * For example, added symlink to /home/folder, and the symlink points to /, this by default is
	 * not allowed, it's only allowed to symlink anything from /home/ and deeper. This is to avoid
	 * great levels of recursion. Enabling this could lead in infinite recursion, and crash the
	 * watcher ( it will try not to avoid this ). Buy enabling out of scope links, it will allow
	 * this behavior. allowOutOfScopeLinks are disabled by default.
	 */
	void allowOutOfScopeLinks( bool allow );

	/// @return Returns if out of scope links are allowed
	const bool& allowOutOfScopeLinks() const;

  private:
	/// The implementation
	FileWatcherImpl* mImpl;
	bool mFollowSymlinks;
	bool mOutOfScopeLinks;
};

/// Basic interface for listening for file events.
/// @class FileWatchListener
class FileWatchListener {
  public:
	virtual ~FileWatchListener() {}

	/// Handles the action file action
	/// @param watchid The watch id for the directory
	/// @param dir The directory
	/// @param filename The filename that was accessed (not full path)
	/// @param action Action that was performed
	/// @param oldFilename The name of the file or directory moved
	virtual void handleFileAction( WatchID watchid, const std::string& dir,
								   const std::string& filename, Action action,
								   std::string oldFilename = "" ) = 0;
};

} // namespace efsw

#endif