/* 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.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-0-11-0/backends/fs/amigaos4/amigaos4-fs.cpp $
 * $Id: amigaos4-fs.cpp 30459 2008-01-12 23:07:51Z sev $
 */

#if defined(__amigaos4__)
#ifdef __USE_INLINE__
#undef __USE_INLINE__
#endif

#include <proto/exec.h>
#include <proto/dos.h>
#include <stdio.h>

#ifndef USE_NEWLIB
#include <strings.h>
#endif

#include "common/util.h"
#include "engines/engine.h"
#include "backends/fs/abstract-fs.h"

#define ENTER() /* debug(6, "Enter") */
#define LEAVE() /* debug(6, "Leave") */

const uint32 kExAllBufferSize = 40960; // TODO: is this okay for sure?

/**
 * Implementation of the ScummVM file system API.
 * 
 * Parts of this class are documented in the base interface class, AbstractFilesystemNode.
 */
class AmigaOSFilesystemNode : public AbstractFilesystemNode {
protected:
	BPTR _pFileLock;
	String _sDisplayName;
	String _sPath;
	bool _bIsDirectory;
	bool _bIsValid;
	
	/**
	 * Obtain the FileInfoBlock protection value for this FilesystemNode,
	 * as defined in the <proto/dos.h> header.
	 * 
	 * @return -1 if there were errors, 0 or a positive integer otherwise.
	 */
	virtual int getFibProtection() const;

public:
	/**
	 * Creates a AmigaOSFilesystemNode with the root node as path.
	 */
	AmigaOSFilesystemNode();
	
	/**
	 * Creates a AmigaOSFilesystemNode for a given path.
	 * 
	 * @param path String with the path the new node should point to.
	 */
	AmigaOSFilesystemNode(const String &p);
	
	/**
	 * FIXME: document this constructor.
	 */
	AmigaOSFilesystemNode(BPTR pLock, const char *pDisplayName = 0);

    /**
     * Copy constructor.
     * 
     * @note Needed because it duplicates the file lock
     */
	AmigaOSFilesystemNode(const AmigaOSFilesystemNode &node);
	
	/**
	 * Destructor.
	 */
	virtual ~AmigaOSFilesystemNode();

	virtual bool exists() const;
	virtual String getDisplayName() const { return _sDisplayName; };
	virtual String getName() const { return _sDisplayName; };
	virtual String getPath() const { return _sPath; };
	virtual bool isDirectory() const { return _bIsDirectory; };
	virtual bool isReadable() const;
	virtual bool isWritable() const;
	
	virtual AbstractFilesystemNode *getChild(const String &n) const;
	virtual bool getChildren(AbstractFSList &list, ListMode mode, bool hidden) const;
	virtual AbstractFilesystemNode *getParent() const;
	
	/**
	 * Creates a list with all the volumes present in the root node.
	 */
	virtual AbstractFSList listVolumes() const;
};

/**
 * Returns the last component of a given path.
 * 
 * @param str String containing the path.
 * @return Pointer to the first char of the last component inside str.
 */
const char *lastPathComponent(const Common::String &str) {
	int offset = str.size();
		
	if (offset <= 0) {
		debug(6, "Bad offset");
		return 0;
	}
	
	const char *p = str.c_str();

	while (offset > 0 && (p[offset-1] == '/' || p[offset-1] == ':'))
		offset--;

	while (offset > 0 && (p[offset-1] != '/' && p[offset-1] != ':'))
		offset--;

	return p + offset;
}

AmigaOSFilesystemNode::AmigaOSFilesystemNode() {
	ENTER();
	_sDisplayName = "Available Disks";
	_bIsValid = true;
	_bIsDirectory = true;
	_sPath = "";
	_pFileLock = 0;
	LEAVE();
}

AmigaOSFilesystemNode::AmigaOSFilesystemNode(const String &p) {
	ENTER();

	int len = 0, offset = p.size();

	//assert(offset > 0);

	if (offset <= 0) {
		debug(6, "Bad offset");
		return;
	}

	_sPath = p;
	_sDisplayName = lastPathComponent(_sPath);
	_pFileLock = 0;
	_bIsDirectory = false;

	struct FileInfoBlock *fib = (struct FileInfoBlock *)IDOS->AllocDosObject(DOS_FIB, NULL);
	if (!fib) {
		debug(6, "FileInfoBlock is NULL");
		LEAVE();
		return;
	}

	// Check whether the node exists and if it is a directory
	BPTR pLock = IDOS->Lock((STRPTR)_sPath.c_str(), SHARED_LOCK);
	if (pLock) {
		if (IDOS->Examine(pLock, fib) != DOSFALSE) {
			if (FIB_IS_DRAWER(fib)) {
				_bIsDirectory = true;
				_pFileLock = IDOS->DupLock(pLock);
				_bIsValid = (_pFileLock != 0);

				// Add a trailing slash if it is needed
				const char c = _sPath.lastChar();
				if (c != '/' && c != ':')
					_sPath += '/';
			}
			else {
				//_bIsDirectory = false;
				_bIsValid = true;
			}			 
		}

		IDOS->UnLock(pLock);
	}

	IDOS->FreeDosObject(DOS_FIB, fib);
	LEAVE();
}

AmigaOSFilesystemNode::AmigaOSFilesystemNode(BPTR pLock, const char *pDisplayName) {
	ENTER();
	int bufSize = MAXPATHLEN;
	_pFileLock = 0;

	while (true) {
		char *n = new char[bufSize];
		if (IDOS->NameFromLock(pLock, (STRPTR)n, bufSize) != DOSFALSE) {
			_sPath = n;
			_sDisplayName = pDisplayName ? pDisplayName : IDOS->FilePart((STRPTR)n);
			delete [] n;
			break;
		}

		if (IDOS->IoErr() != ERROR_LINE_TOO_LONG) {
			_bIsValid = false;
			debug(6, "IoErr() != ERROR_LINE_TOO_LONG");
			LEAVE();
			delete [] n;
			return;
		}
		
		bufSize *= 2;
		delete [] n;
	}

	_bIsValid =	false;
	_bIsDirectory = false;

	struct FileInfoBlock *fib = (struct	FileInfoBlock *)IDOS->AllocDosObject(DOS_FIB, NULL);
	if (!fib) {
		debug(6, "FileInfoBlock is NULL");
		LEAVE();
		return;
	}

	if (IDOS->Examine(pLock, fib) != DOSFALSE) {
		if (FIB_IS_DRAWER(fib)) {
			_bIsDirectory = true;
			_pFileLock = IDOS->DupLock(pLock);
			_bIsValid = _pFileLock != 0;

			const char c = _sPath.lastChar();
			if (c != '/' && c != ':')
				_sPath += '/';
		}
		else {
			//_bIsDirectory = false;
			_bIsValid = true;
		}		 
	}

	IDOS->FreeDosObject(DOS_FIB, fib);
	LEAVE();
}

// We need the custom copy constructor because of DupLock()
AmigaOSFilesystemNode::AmigaOSFilesystemNode(const AmigaOSFilesystemNode& node) {
	ENTER();
	_sDisplayName = node._sDisplayName;
	_bIsValid = node._bIsValid;
	_bIsDirectory = node._bIsDirectory;
	_sPath = node._sPath;
	_pFileLock = IDOS->DupLock(node._pFileLock);
	LEAVE();
}

AmigaOSFilesystemNode::~AmigaOSFilesystemNode() {
	ENTER();
	if (_pFileLock)
		IDOS->UnLock(_pFileLock);
	LEAVE();
}

bool AmigaOSFilesystemNode::exists() const {
	ENTER();
	if(_sPath.empty())
		return false;
	
	bool nodeExists = false;
	
	struct FileInfoBlock *fib = (struct FileInfoBlock *)IDOS->AllocDosObject(DOS_FIB, NULL);
	if (!fib) {
		debug(6, "FileInfoBlock is NULL");
		LEAVE();
		return false;
	}
	
	BPTR pLock = IDOS->Lock((STRPTR)_sPath.c_str(), SHARED_LOCK);
	if (pLock) {
		if (IDOS->Examine(pLock, fib) != DOSFALSE)
			nodeExists = true;
		IDOS->UnLock(pLock);
	}
	
	IDOS->FreeDosObject(DOS_FIB, fib);
	LEAVE();
	return nodeExists;
}

AbstractFilesystemNode *AmigaOSFilesystemNode::getChild(const String &n) const {
	ENTER();
	if (!_bIsDirectory) {
		debug(6, "Not a directory");
		return 0;
	}

	String newPath(_sPath);

	if (_sPath.lastChar() != '/')
		newPath += '/';

	newPath += n;
	BPTR lock = IDOS->Lock(newPath.c_str(), SHARED_LOCK);

	if (!lock) {
		debug(6, "Bad path");
		return 0;
	}

	IDOS->UnLock(lock);

	LEAVE();
	return new AmigaOSFilesystemNode(newPath);
}

bool AmigaOSFilesystemNode::getChildren(AbstractFSList &myList, ListMode mode, bool hidden) const {
	ENTER();

	//TODO: honor the hidden flag

	if (!_bIsValid) {
		debug(6, "Invalid node");
		LEAVE();
		return false; // Empty list
	}

	if (!_bIsDirectory) {
		debug(6, "Not a directory");
		LEAVE();
		return false; // Empty list
	}

	if (_pFileLock == 0) {
		debug(6, "Root node");
		LEAVE();
		myList = listVolumes();
		return true;
	}

	struct ExAllControl *eac = (struct ExAllControl *)IDOS->AllocDosObject(DOS_EXALLCONTROL, 0);
	if (eac) {
		struct ExAllData *data = (struct ExAllData *)IExec->AllocVec(kExAllBufferSize, MEMF_ANY);
		if (data) {
			BOOL bExMore;
			eac->eac_LastKey = 0;
			do {
				// Examine directory
				bExMore = IDOS->ExAll(_pFileLock, data,	kExAllBufferSize, ED_TYPE, eac);

				LONG error = IDOS->IoErr();
				if (!bExMore && error != ERROR_NO_MORE_ENTRIES)
					break; // Abnormal failure

				if (eac->eac_Entries ==	0)
					continue; // Normal failure, no entries

				struct ExAllData *ead = data;
				do {
					if ((mode == FilesystemNode::kListAll) ||
						(EAD_IS_DRAWER(ead) && (mode == FilesystemNode::kListDirectoriesOnly)) ||
						(EAD_IS_FILE(ead) && (mode == FilesystemNode::kListFilesOnly))) {
						String full_path = _sPath;
						full_path += (char*)ead->ed_Name;

						BPTR lock = IDOS->Lock((STRPTR)full_path.c_str(), SHARED_LOCK);
						if (lock) {
							AmigaOSFilesystemNode *entry = new AmigaOSFilesystemNode(lock, (char *)ead->ed_Name);
							if (entry) {
								//FIXME: since the isValid() function is no longer part of the AbstractFilesystemNode
								//       specification, the following call had to be changed:
								//       	if (entry->isValid())
								//		 Please verify that the logic of the code remains coherent. Also, remember
								//		 that the isReadable() and isWritable() methods are available.
								if (entry->exists())
								    myList.push_back(entry);
								else
									delete entry;
							}
							IDOS->UnLock(lock);
						}
					}
					ead = ead->ed_Next;
				} while (ead);
			} while (bExMore);

			IExec->FreeVec(data);
		}

		IDOS->FreeDosObject(DOS_EXALLCONTROL, eac);
	}

	LEAVE();
	
	return true;
}

int AmigaOSFilesystemNode::getFibProtection() const {
	ENTER();
	
	int fibProt = -1;
	struct FileInfoBlock *fib = (struct FileInfoBlock *)IDOS->AllocDosObject(DOS_FIB, NULL);
	if (!fib) {
		debug(6, "FileInfoBlock is NULL");
		LEAVE();
		return fibProt;
	}
	
	BPTR pLock = IDOS->Lock((STRPTR)_sPath.c_str(), SHARED_LOCK);
	if (pLock) {
		if (IDOS->Examine(pLock, fib) != DOSFALSE) {
			fibProt = fib->fib_Protection;
		}
		IDOS->UnLock(pLock);
	}
	
	IDOS->FreeDosObject(DOS_FIB, fib);
	LEAVE();
	return fibProt;
}

AbstractFilesystemNode *AmigaOSFilesystemNode::getParent() const {
	ENTER();

	if (!_bIsDirectory) {
		debug(6, "Not a directory");
		LEAVE();
		return 0;
	}

	if (_pFileLock == 0) {
		debug(6, "Root node");
		LEAVE();
		return new AmigaOSFilesystemNode(*this);
	}

	AmigaOSFilesystemNode *node;

	BPTR parentDir = IDOS->ParentDir( _pFileLock );
	if (parentDir) {
		node = new AmigaOSFilesystemNode(parentDir);
		IDOS->UnLock(parentDir);
	}
	else
		node = new AmigaOSFilesystemNode();

	LEAVE();
	
	return node;
}

bool AmigaOSFilesystemNode::isReadable() const {
	bool readable = false;
	int fibProt = getFibProtection();
	
	if (fibProt >= 0) {
		/* The fib_Protection flag is low-active or inverted, thus the negation.
		 * 
		 * For more information, consult the compiler/include/dos/dos.h
		 * file from the AROS source (http://aros.sourceforge.net/).
		 */
		readable = !(fibProt & FIBF_READ);
	}
	
	return readable;
}

bool AmigaOSFilesystemNode::isWritable() const {
	bool writable = false;
	int fibProt = getFibProtection();
	
	if (fibProt >= 0) {
		/* The fib_Protection flag is low-active or inverted, thus the negation.
		 * 
		 * For more information, consult the compiler/include/dos/dos.h
		 * file from the AROS source (http://aros.sourceforge.net/).
		 */
		writable = !(fibProt & FIBF_WRITE);
	}
	
	return writable;
}

AbstractFSList AmigaOSFilesystemNode::listVolumes()	const {
	ENTER();

	AbstractFSList myList;

	const uint32 kLockFlags = LDF_READ | LDF_VOLUMES;
	char buffer[MAXPATHLEN];

	struct DosList *dosList = IDOS->LockDosList(kLockFlags);
	if (!dosList) {
		debug(6, "Cannot lock the DOS list");
		LEAVE();
		return myList;
	}

	dosList = IDOS->NextDosEntry(dosList, LDF_VOLUMES);
	while (dosList) {
		if (dosList->dol_Type == DLT_VOLUME &&
			dosList->dol_Name &&
			dosList->dol_Task) {
			//const char *volName = (const char *)BADDR(dosList->dol_Name)+1;
			
			// Copy name to buffer
			IDOS->CopyStringBSTRToC(dosList->dol_Name, buffer, MAXPATHLEN);

			//const char *devName = (const char *)((struct Task *)dosList->dol_Task->mp_SigTask)->tc_Node.ln_Name;

			// Volume name + '\0'
			char *volName = new char [strlen(buffer) + 1];

			strcpy(volName, buffer);

			strcat(buffer, ":");

			BPTR volumeLock = IDOS->Lock((STRPTR)buffer, SHARED_LOCK);
			if (volumeLock) {

				char *devName = new char [MAXPATHLEN];

				// Find device name
				IDOS->DevNameFromLock(volumeLock, devName, MAXPATHLEN, DN_DEVICEONLY);
				
				sprintf(buffer, "%s (%s)", volName, devName);

				delete [] devName;

				AmigaOSFilesystemNode *entry = new AmigaOSFilesystemNode(volumeLock, buffer);
				if (entry) {
					//FIXME: since the isValid() function is no longer part of the AbstractFilesystemNode
					//       specification, the following call had to be changed:
					//       	if (entry->isValid())
					//		 Please verify that the logic of the code remains coherent. Also, remember
					//		 that the isReadable() and isWritable() methods are available.
					if(entry->exists())
						myList.push_back(entry);
					else
						delete entry;
				}

				IDOS->UnLock(volumeLock);
			}

			delete [] volName;
		}
		dosList	= IDOS->NextDosEntry(dosList, LDF_VOLUMES);
	}

	IDOS->UnLockDosList(kLockFlags);

	LEAVE();
	
	return myList;
}

#endif //defined(__amigaos4__)
