// -*- C++ -*-
/**
 * \file EmbeddedFiles.h
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Bo Peng
 *
 * Full author contact details are available in file CREDITS.
 *
 */

#ifndef EMBEDDEDFILES_H
#define EMBEDDEDFILES_H

#include "support/FileName.h"

#include <vector>
#include <utility>

#include "ParIterator.h"
#include "Paragraph.h"

/**

This file, and the embedding dialog implemented in src/frontends, implements
an 'Embedded Files' feature of lyx.


Expected features:
=========================

1. With embedding enabled (disabled by default), .lyx file can embed graphics,
listings, bib file etc.

2. Embedding of certain files are automatic (graphics, bib etc), and
other files can be embedded manually.

3. Embedded file.lyx file is a zip file, with file.lyx, manifest.txt
and embedded files. 

4. Embedded files can be "EMBEDDED", "EXTERNAL", or "AUTO". In the
"AUTO" mode, external files will be used if available; otherwise the
embedded version will be used. In this way, users can work as usual by
modifying external listings, graphics, and do not have to worry about
embedding. "EMBEDDED" and "EXTERNAL" modes ignore or use external files
respectively.

5. An embedding dialog is provided to change embedding status (buffer
level or individual embedded files), manually embed, extract, view
or edit files.

Overall, this feature allows two ways of editing a .lyx file

a. The continuous use of the pure-text .lyx file format with external
files. This is the default file format, and allows external editing
of .lyx file and better use of version control systems.

b. The embedded way. Figures etc are inserted to .lyx file and will
be embedded. These embedded files can be viewed or edited through
the embedding dialog. This file can be shared with others more
easily. The advantage of lyx' embedding approach is that external files
will be automatically used and embedded if the file is in "AUTO" mode.


Implementation:
======================

1. An EmbeddedFiles class is implemented to keep the embedded files (
class EmbeddedFile). (c.f. src/EmbeddedFiles.[h|cpp])
This class keeps a manifest that has
  a. external relative filename
  b. inzip filename. It is the relative path name if the embedded file is
    in or under the document directory, or file name otherwise. Name aliasing
    is used if two external files share the same name.
  c. embedding mode.
It also provides functions to
  a. manipulate manifest
  b. scan a buffer for embeddable files
  c. look up inzipname from external filename
  d. look up external filename from inzipname

2. When a file is saved, it is scanned for embedded files. (c.f.
EmbeddedFiles::update(), Inset::registerEmbeddedFiles()).

3. When a lyx file file.lyx is saved, it is save to tmppath() first.
Embedded files are compressed along with file.lyx and a manifest.txt. 
If embedding is disabled, file.lyx is saved in the usual pure-text form.
(c.f. Buffer::writeFile(), EmbeddedFiles::write())

4. When a lyx file.lyx file is opened, if it is a zip file, it is
decompressed to tmppath(). If manifest.txt and file.lyx exists in
tmppath(), the manifest is read to buffer, and tmppath()/file.lyx is
read as usual. If file.lyx is not a zip file, it is read as usual.
(c.f. bool Buffer::readFile())

5. A menu item Document -> Embedded Files is provided to open
a embedding dialog. It handles a EmbddedFiles point directly.
From this dialog, a user can disable embedding, change embedding status,
or embed other files, extract, view, edit files.

6. When a lyx file is loaded, Embedded files can have
  a. both external and internal copy
  b. only external copy (filename())
  c. only embedded copy (temppath()/inzipname)
And each can have "AUTO", "EXTERNAL", "EMBEDDED" status. Proper
handling of each case is required.

7. If embedding of a .lyx file with embedded files is disabled, all its
embedded files are copied to their respective external filenames. This
is why external filename will exist even if a file is at "EMBEDDED" status.

8. Individual embeddable insets should find ways to handle embedded files.
InsetGraphics replace params().filename with its temppath()/inzipname version
when the inset is created. The filename appears as /tmp/..../inzipname
when lyx runs. When params().filename is saved, lyx checks if this is an
embedded file (check path == temppath()), if so, save filename() instead.
(c.f. InsetGraphic::read(), InsetGraphics::edit(), InsetGraphicsParams::write())


*/

namespace lyx {

class Buffer;

class EmbeddedFile : public support::DocFileName
{
public:
	/**
		Embedding status of this DocFileName.
	 */
	enum STATUS {
		// uninitialized/invalid status
		NONE,
		// If the external version of the file is available, it will be used
		// to generate output, and be embedded to the saved lyx file.
		// Otherwise, embedded version will be used.
		AUTO,
		// Always use embedded version. The file will be embedded even
		// if the file is no longer referred by the document.
		EMBEDDED,
		// Do not embed this file, always use external version.
		EXTERNAL
	};

	EmbeddedFile(std::string const & file, std::string const & inzip_name,
		STATUS status, ParConstIterator const & pit);

	/// filename in the zip file, usually the relative path
	std::string inzipName() const { return inzip_name_; }
	/// embedded file, equals to temppath()/inzipName()
	std::string embeddedFile(Buffer const * buf) const;

	/// paragraph id
	void setParIter(ParConstIterator const & pit);
	int const parID() const;

	/// embedding status of this file
	bool embedded() const { return status_ != EXTERNAL; }
	STATUS status() const { return status_; }
	void setStatus(STATUS status) {	status_ = status; }

	// A flag indicating whether or not this filename is valid.
	// When lyx runs, InsetGraphics etc may be added or removed so filename
	// maybe obsolete. In Buffer::updateEmbeddedFiles, the EmbeddedFiles is first
	// invalidated (c.f. invalidate()), and all insets are asked to register
	// embedded files. In this way, EmbeddedFileList will be refreshed, with
	// status setting untouched.
	bool valid() const { return valid_; }
	void validate() { valid_ = true; }
	void invalidate() {	valid_ = false;	}

private:
	/// filename in zip file
	std::string inzip_name_;
	/// the status of this docfile
	STATUS status_;
	///
	bool valid_;
	/// Current position of the item, used to locate the files
	/// A figure may be referred by several items. In this case
	/// only the last location is recorded.
	ParConstIterator par_it_;
};


class EmbeddedFiles {
public:
	typedef std::vector<EmbeddedFile> EmbeddedFileList;
public:
	///
	EmbeddedFiles(Buffer * buffer = NULL): file_list_(), buffer_(buffer) {}
	///
	~EmbeddedFiles() {}

	/// return buffer params embedded flag
	bool enabled() const;
	/// set buffer params embedded flag
	void enable(bool flag);

	/// add a file item
	void registerFile(std::string const & filename,
		EmbeddedFile::STATUS status = EmbeddedFile::AUTO,
		ParConstIterator const & pit = ParConstIterator());

	/// scan the buffer and get a list of EmbeddedFile
	void update();

	/// write a zip file
	bool write(support::DocFileName const & filename);

	void clear() { file_list_.clear(); }

	///
	EmbeddedFile & operator[](size_t idx) { return *(file_list_.begin() + idx); }
	EmbeddedFile const & operator[](size_t idx) const { return *(file_list_.begin() + idx); }
	///
	EmbeddedFileList::iterator begin() { return file_list_.begin(); }
	EmbeddedFileList::iterator end() { return file_list_.end(); }
	EmbeddedFileList::const_iterator begin() const { return file_list_.begin(); }
	EmbeddedFileList::const_iterator end() const { return file_list_.end(); }

	///
	friend std::istream & operator>> (std::istream & is, EmbeddedFiles &);

	friend std::ostream & operator<< (std::ostream & os, EmbeddedFiles const &);
private:
	/// get a unique inzip name
	std::string const getInzipName(std::string const & name);
	/// list of embedded files
	EmbeddedFileList file_list_;
	///
	Buffer * buffer_;
};


std::istream & operator>> (std::istream & is, EmbeddedFiles &);

std::ostream & operator<< (std::ostream & os, EmbeddedFiles const &);

}
#endif