// =================================================================================================
// ADOBE SYSTEMS INCORPORATED
// Copyright 2008 Adobe Systems Incorporated
// All Rights Reserved
//
// NOTICE: Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
// =================================================================================================

#include "public/include/XMP_Environment.h"	// ! XMP_Environment.h must be the first included header.

#include "public/include/XMP_Const.h"
#include "public/include/XMP_IO.hpp"

#include "XMPFiles/source/XMPFiles_Impl.hpp"
#include "XMPFiles/source/FormatSupport/Reconcile_Impl.hpp"
#include "source/UnicodeConversions.hpp"
#include "source/XMPFiles_IO.hpp"
#include "source/XIO.hpp"

#include "XMPFiles/source/FileHandlers/MP3_Handler.hpp"

#include <sstream>

// =================================================================================================
/// \file MP3_Handler.cpp
/// \brief MP3 handler class.
// =================================================================================================

// =================================================================================================
// Helper structs and private routines
// ====================
struct ReconProps {
	const char* mainID;	// The stored v2.3 and v2.4 ID, also used as the main logical ID.
	const char* v22ID;	// The stored v2.2 ID.
	const char* ns;
	const char* prop;
};

const static XMP_Uns32 XMP_V23_ID = 0x50524956;	// PRIV
const static XMP_Uns32 XMP_V22_ID = 0x50525600;	// PRV

const static ReconProps reconProps[] = {
	{ "TPE1", "TP1", kXMP_NS_DM,	"artist" },
	{ "TALB", "TAL", kXMP_NS_DM,	"album"  },
	{ "TRCK", "TRK", kXMP_NS_DM,	"trackNumber"  },
	// exceptions that need attention:
	{ "TCON", "TCO", kXMP_NS_DM,	"genre"  }, // genres might be numeric
	{ "TIT2", "TT2", kXMP_NS_DC,	"title"  }, // ["x-default"] language alternatives
	{ "COMM", "COM", kXMP_NS_DM,	"logComment"  }, // two distinct strings, language alternative

	{ "TYER", "TYE", kXMP_NS_XMP,	"CreateDate"  }, // Year (YYYY) Deprecated in 2.4
	{ "TDAT", "TDA", kXMP_NS_XMP,	"CreateDate"  }, // Date (DDMM) Deprecated in 2.4
	{ "TIME", "TIM", kXMP_NS_XMP,	"CreateDate"  }, // Time (HHMM) Deprecated in 2.4
	{ "TDRC", "", kXMP_NS_XMP,	"CreateDate"  }, // assembled date/time v2.4

	// new reconciliations introduced in Version 5
	{ "TCMP", "TCP", kXMP_NS_DM,	"partOfCompilation"  },	// presence/absence of TCMP frame dedides
	{ "USLT", "ULT", kXMP_NS_DM,	"lyrics"  },
	{ "TCOM", "TCM", kXMP_NS_DM,	"composer"  },
	{ "TPOS", "TPA", kXMP_NS_DM,	"discNumber"  },		// * a text field! might contain "/<total>"
	{ "TCOP", "TCR", kXMP_NS_DC,	"rights"  },  // ["x-default"] language alternatives
	{ "TPE4", "TP4", kXMP_NS_DM,	"engineer"  },
	{ "WCOP", "WCP", kXMP_NS_XMP_Rights,	"WebStatement"  },

	{ 0, 0, 0, 0 }	// must be last as a sentinel
};

// =================================================================================================
// MP3_MetaHandlerCTor
// ====================

XMPFileHandler * MP3_MetaHandlerCTor ( XMPFiles * parent )
{
	return new MP3_MetaHandler ( parent );
}

// =================================================================================================
// MP3_CheckFormat
// ===============

// For MP3 we check parts .... See the MP3 spec for offset info.

bool MP3_CheckFormat ( XMP_FileFormat format,
					  XMP_StringPtr  filePath,
					  XMP_IO*    file,
					  XMPFiles *     parent )
{
	IgnoreParam(format); IgnoreParam(filePath); IgnoreParam(parent);	//suppress warnings
	XMP_Assert ( format == kXMP_MP3File );		//standard assert

	if ( file->Length() < 10 ) return false;
	file ->Rewind();

	XMP_Uns8 header[3];
	file->ReadAll ( header, 3 );
	if ( ! CheckBytes( &header[0], "ID3", 3 ) ) return (parent->format == kXMP_MP3File);

	XMP_Uns8 major = XIO::ReadUns8( file );
	XMP_Uns8 minor = XIO::ReadUns8( file );

	if ( (major < 2) || (major > 4) || (minor == 0xFF) ) return false;

	XMP_Uns8 flags = XIO::ReadUns8 ( file );

	//TODO
	if ( flags & 0x10 ) XMP_Throw ( "no support for MP3 with footer", kXMPErr_Unimplemented );
	if ( flags & 0x80 ) return false; //no support for unsynchronized MP3 (as before, also see [1219125])
	if ( flags & 0x0F ) XMP_Throw ( "illegal header lower bits", kXMPErr_Unimplemented );

	XMP_Uns32 size = XIO::ReadUns32_BE ( file );
	if ( (size & 0x80808080) != 0 ) return false; //if any bit survives -> not a valid synchsafe 32 bit integer

	return true;
	
}	// MP3_CheckFormat


// =================================================================================================
// MP3_MetaHandler::MP3_MetaHandler
// ================================

MP3_MetaHandler::MP3_MetaHandler ( XMPFiles * _parent )
{
	this->oldTagSize = 0;
	this->oldPadding = 0;
	this->oldFramesSize = 0;
	this->newTagSize = 0;
	this->newPadding = 0;
	this->newFramesSize = 0;
	this->tagIsDirty = false;
	this->mustShift = false;
	this->majorVersion = 2;
	this->minorVersion = 3;
	this->hasID3Tag = false;
	this->hasFooter = false;
	this->extHeaderSize = 0;
	this->hasExtHeader = false;
	this->parent = _parent;
	this->handlerFlags = kMP3_HandlerFlags;
	this->stdCharForm  = kXMP_Char8Bit;
}

// =================================================================================================
// MP3_MetaHandler::~MP3_MetaHandler
// =================================

MP3_MetaHandler::~MP3_MetaHandler()
{
	// free frames
	ID3v2Frame* curFrame;
	while ( !this->framesVector.empty() ) {
		curFrame = this->framesVector.back();
		delete curFrame;
		framesVector.pop_back();
	}
}

// =================================================================================================
// MP3_MetaHandler::CacheFileData
// ==============================

void MP3_MetaHandler::CacheFileData()
{

	//*** abort procedures
	this->containsXMP = false;		//assume no XMP for now

	XMP_IO* file = this->parent->ioRef;
	/* XMP_PacketInfo &packetInfo = this->packetInfo; */

	file->Rewind();

	this->hasID3Tag = this->id3Header.read( file );
	this->majorVersion = this->id3Header.fields[ID3Header::o_vMajor];
	this->minorVersion = this->id3Header.fields[ID3Header::o_vMinor];
	this->hasExtHeader = (0 != ( 0x40 & this->id3Header.fields[ID3Header::o_flags])); //'naturally' false if no ID3Tag
	this->hasFooter = ( 0 != ( 0x10 & this->id3Header.fields[ID3Header::o_flags])); //'naturally' false if no ID3Tag

	// stored size is w/o initial header (thus adding 10)
	// + but extended header (if existing)
	// + padding + frames after unsynchronisation (?)
	// (if no ID3 tag existing, constructed default correctly sets size to 10.)
	this->oldTagSize = ID3Header::kID3_TagHeaderSize + synchToInt32(GetUns32BE( &id3Header.fields[ID3Header::o_size] ));

	if ( ! hasExtHeader ) {

		this->extHeaderSize = 0; // := there is no such header.

	} else {

		this->extHeaderSize = synchToInt32( XIO::ReadInt32_BE( file));
		/*XMP_Uns8 extHeaderNumFlagBytes =*/ XIO::ReadUns8( file );

		// v2.3 doesn't include the size, while v2.4 does
		if ( this->majorVersion < 4 ) this->extHeaderSize += 4;
		XMP_Validate( this->extHeaderSize >= 6, "extHeader size too small", kXMPErr_BadFileFormat );

		file->Seek ( this->extHeaderSize - 6, kXMP_SeekFromCurrent );

	}

	this->framesVector.clear(); //mac precaution
	ID3v2Frame* curFrame = 0; // reusable

	////////////////////////////////////////////////////
	// read frames
	
	XMP_Uns32 xmpID = XMP_V23_ID;
	if ( this->majorVersion == 2 )
	{
		xmpID = XMP_V22_ID;
	}

	while ( file->Offset() < this->oldTagSize ) {

		curFrame = new ID3v2Frame();

		try {
			XMP_Int64 frameSize = curFrame->read ( file, this->majorVersion );
			if ( frameSize == 0 ) {
				delete curFrame; // ..since not becoming part of vector for latter delete.
				break;			 // not a throw. There's nothing wrong with padding.
			}
			this->containsXMP = true;
		} catch ( ... ) {
			delete curFrame;
			throw;
		}

		// these are both pointer assignments, no (copy) construction
		// (MemLeak Note: for all things pushed, memory cleanup is taken care of in destructor.)
		this->framesVector.push_back ( curFrame );

		//remember XMP-Frame, if it occurs:
		if ( (curFrame->id ==xmpID) &&
			 (curFrame->contentSize > 8) && CheckBytes ( &curFrame->content[0], "XMP\0", 4 ) ) {

			// be sure that this is the first packet (all else would be illegal format)
			XMP_Validate ( this->framesMap[xmpID] == 0, "two XMP packets in one file", kXMPErr_BadFileFormat );
			//add this to map, needed on reconciliation
			this->framesMap[xmpID] = curFrame;
	
			this->packetInfo.length = curFrame->contentSize - 4; // content minus "XMP\0"
			this->packetInfo.offset = ( file->Offset() - this->packetInfo.length );
	
			this->xmpPacket.erase(); //safety
			this->xmpPacket.assign( &curFrame->content[4], curFrame->contentSize - 4 );
			this->containsXMP = true; // do this last, after all possible failure
		
		}

		// No space for another frame? => assume into ID3v2.4 padding.
		XMP_Int64 newPos = file->Offset();
		XMP_Int64 spaceLeft = this->oldTagSize - newPos;	// Depends on first check below!
		if ( (newPos > this->oldTagSize) || (spaceLeft < (XMP_Int64)ID3Header::kID3_TagHeaderSize) ) break;

	}

	////////////////////////////////////////////////////
	// padding

	this->oldPadding = this->oldTagSize - file->Offset();
	this->oldFramesSize = this->oldTagSize - ID3Header::kID3_TagHeaderSize - this->oldPadding;

	XMP_Validate ( (this->oldPadding >= 0), "illegal oldTagSize or padding value", kXMPErr_BadFileFormat );

	for ( XMP_Int64 i = this->oldPadding; i > 0; ) {
		if ( i >= 8 ) {
			if ( XIO::ReadInt64_BE(file) != 0 ) XMP_Throw ( "padding not nulled out", kXMPErr_BadFileFormat );
			i -= 8;
			continue;
		}
		if ( XIO::ReadUns8(file) != 0) XMP_Throw ( "padding(2) not nulled out", kXMPErr_BadFileFormat );
		i--;
	}

	//// read ID3v1 tag
	if ( ! this->containsXMP ) this->containsXMP = id3v1Tag.read ( file, &this->xmpObj );

}	// MP3_MetaHandler::CacheFileData


// =================================================================================================
// MP3_MetaHandler::ProcessXMP
// ===========================
//
// Process the raw XMP and legacy metadata that was previously cached.

void MP3_MetaHandler::ProcessXMP()
{

	// Process the XMP packet.
	if ( ! this->xmpPacket.empty() ) {
		XMP_Assert ( this->containsXMP );
		XMP_StringPtr packetStr = this->xmpPacket.c_str();
		XMP_StringLen packetLen = (XMP_StringLen) this->xmpPacket.size();
		this->xmpObj.ParseFromBuffer ( packetStr, packetLen );
		this->processedXMP = true;
	}

	///////////////////////////////////////////////////////////////////
	// assumptions on presence-absence "flag tags"
	//   ( unless no xmp whatsoever present )
	if ( ! this->xmpPacket.empty() ) this->xmpObj.SetProperty ( kXMP_NS_DM, "partOfCompilation", "false" );

	////////////////////////////////////////////////////////////////////
	// import of legacy properties
	ID3v2Frame* curFrame;
	XMP_Bool hasTDRC = false;
	XMP_DateTime newDateTime;

	if ( this->hasID3Tag ) {	// otherwise pretty pointless...

		for ( int r = 0; reconProps[r].mainID != 0; ++r ) {

			//get the frame ID to look for
			XMP_Uns32 logicalID = GetUns32BE ( reconProps[r].mainID );
			XMP_Uns32 storedID = logicalID;
			if ( this->majorVersion == 2 ) storedID = GetUns32BE ( reconProps[r].v22ID );

			// deal with each such frame in the frameVector
			// (since there might be several, some of them not applicable, i.e. COMM)

			vector<ID3_Support::ID3v2Frame*>::iterator it;
			for ( it = this->framesVector.begin(); it != this->framesVector.end(); ++it ) {

				curFrame = *it;
				if ( storedID != curFrame->id ) continue;

				// go deal with it!
				// get the property
				std::string id3Text, xmpText;
				bool result = curFrame->getFrameValue ( this->majorVersion, logicalID, &id3Text );
				if ( ! result ) continue; //ignore but preserve this frame (i.e. not applicable COMM frame)

				//////////////////////////////////////////////////////////////////////////////////
				// if we come as far as here, it's proven that there's a relevant XMP property

				this->containsXMP = true;

				ID3_Support::ID3v2Frame* t = this->framesMap [ storedID ];
				if ( t != 0 )  t->active = false;

				// add this to map (needed on reconciliation)
				// note: above code reaches, that COMM/USLT frames
				// only then reach this map, if they are 'eng'(lish)
				// multiple occurences indeed leads to last one survives
				// ( in this map, all survive in the file )
				this->framesMap [ storedID ] = curFrame;

				// now write away as needed;
				// merely based on existence, relevant even if empty:
				if ( logicalID == 0x54434D50) {	// TCMP if exists: part of compilation

					this->xmpObj.SetProperty ( kXMP_NS_DM, "partOfCompilation", "true" );

				} else if ( ! id3Text.empty() ) {

					switch ( logicalID ) {

						case 0x54495432: // TIT2 -> title["x-default"]
						case 0x54434F50: // TCOP -> rights["x-default"]
							this->xmpObj.SetLocalizedText ( reconProps[r].ns, reconProps[r].prop,"", "x-default", id3Text );
							break;

						case 0x54434F4E: // TCON -> genre
							ID3_Support::GenreUtils::ConvertGenreToXMP ( id3Text.c_str(), &xmpText );
							if ( ! xmpText.empty() ) {
								this->xmpObj.SetProperty ( reconProps[r].ns, reconProps[r].prop, xmpText );
							}
							break;

						case 0x54594552: // TYER -> xmp:CreateDate.year
							{
								try {	// Don't let wrong dates in id3 stop import.
									if ( ! hasTDRC ) {
										newDateTime.year = SXMPUtils::ConvertToInt ( id3Text );
										newDateTime.hasDate = true;
									}
								} catch ( ... ) {
										// Do nothing, let other imports proceed.
								}
								break;
							}

						case 0x54444154: //TDAT	-> xmp:CreateDate.month and day
							{
								try {	// Don't let wrong dates in id3 stop import.
									// only if no TDRC has been found before
									//&& must have the format DDMM
									if ( (! hasTDRC) && (id3Text.length() == 4) ) {
										newDateTime.day = SXMPUtils::ConvertToInt (id3Text.substr(0,2));
										newDateTime.month = SXMPUtils::ConvertToInt ( id3Text.substr(2,2));
										newDateTime.hasDate = true;
									}
								} catch ( ... ) {
									// Do nothing, let other imports proceed.
								}
								break;
							}

						case 0x54494D45: //TIME	-> xmp:CreateDate.hours and minutes
							{
								try {	// Don't let wrong dates in id3 stop import.
									// only if no TDRC has been found before
									// && must have the format HHMM
									if ( (! hasTDRC) && (id3Text.length() == 4) ) {
										newDateTime.hour = SXMPUtils::ConvertToInt (id3Text.substr(0,2));
										newDateTime.minute = SXMPUtils::ConvertToInt ( id3Text.substr(2,2));
										newDateTime.hasTime = true;
									}
								} catch ( ... ) {
									// Do nothing, let other imports proceed.
								}
								break;
							}

						case 0x54445243: // TDRC -> xmp:CreateDate //id3 v2.4
							{
								try {	// Don't let wrong dates in id3 stop import.
									hasTDRC = true;
									// This always wins over TYER, TDAT and TIME
									SXMPUtils::ConvertToDate ( id3Text, &newDateTime );
								} catch ( ... ) {
									// Do nothing, let other imports proceed.
								}
								break;
							}

						default:
							// NB: COMM/USLT need no special fork regarding language alternatives/multiple occurence.
							//		relevant code forks are in ID3_Support::getFrameValue()
							this->xmpObj.SetProperty ( reconProps[r].ns, reconProps[r].prop, id3Text );
							break;

					}//switch
					
				}

			} //for iterator

		}//for reconProps

		// import DateTime
        XMP_DateTime oldDateTime;
        bool haveNewDateTime  = newDateTime.year != 0 ;
        if ( xmpObj.GetProperty_Date ( kXMP_NS_XMP, "CreateDate", &oldDateTime, 0 ) )
        {

            haveNewDateTime = haveNewDateTime && ( (newDateTime.year != oldDateTime.year) || ( (newDateTime.month != 0 )
							  && ( (newDateTime.day != oldDateTime.day) || (newDateTime.month != oldDateTime.month) ) )
							  || ( newDateTime.hasTime && ( (newDateTime.hour != oldDateTime.hour) || (newDateTime.minute != oldDateTime.minute) ) ) );
        }
            // NOTE: no further validation nessesary the function "SetProperty_Date" will care about validating date and time
            // any exception will be caught and block import
        try {
            if ( haveNewDateTime ) {
                    this->xmpObj.SetProperty_Date ( kXMP_NS_XMP, "CreateDate", newDateTime );
            }
        } catch ( ... ) {
            // Dont import invalid dates from ID3
        }

	}

	// very important to avoid multiple runs! (in which case I'd need to clean certain
	// fields (i.e. regarding ->active setting)
	this->processedXMP = true;

}	// MP3_MetaHandler::ProcessXMP


// =================================================================================================
// MP3_MetaHandler::UpdateFile
// ===========================
void MP3_MetaHandler::UpdateFile ( bool doSafeUpdate )
{
	if ( doSafeUpdate ) XMP_Throw ( "MP3_MetaHandler::UpdateFile: Safe update not supported", kXMPErr_Unavailable );

	XMP_IO* file = this->parent->ioRef;

	// leave 2.3 resp. 2.4 header, since we want to let alone
	// and don't know enough about the encoding of unrelated frames...
	XMP_Assert( this->containsXMP );

	tagIsDirty = false;
	mustShift = false;

	// write out native properties:
	// * update existing ones
	// * create new frames as needed
	// * delete frames if property is gone!
	// see what there is to do for us:

	// RECON LOOP START
	for (int r = 0; reconProps[r].mainID != 0; r++ ) {

		std::string value;
		bool needDescriptor = false;
		bool needEncodingByte = true;

		XMP_Uns32 logicalID = GetUns32BE ( reconProps[r].mainID );
		XMP_Uns32 storedID = logicalID;
		if ( this->majorVersion == 2 ) storedID = GetUns32BE ( reconProps[r].v22ID );

		ID3v2Frame* frame = framesMap[ storedID ];	// the actual frame (if already existing)

		// get XMP property
		//	* honour specific exceptions
		//  * leave value empty() if it doesn't exist ==> frame must be delete/not created
		switch ( logicalID ) {

			case 0x54434D50: // TCMP if exists: part of compilation
				if ( xmpObj.GetProperty( kXMP_NS_DM, "partOfCompilation", &value, 0 ) && ( 0 == stricmp( value.c_str(), "true" ) )) {
					value = "1"; // set a TCMP frame of value 1
				} else {
					value.erase(); // delete/prevent creation of frame
				}
				break;
	
			case 0x54495432: // TIT2 -> title["x-default"]
			case 0x54434F50: // TCOP -> rights["x-default"]
				if (! xmpObj.GetLocalizedText( reconProps[r].ns, reconProps[r].prop, "", "x-default", 0, &value, 0 )) value.erase(); // if not, erase string.
				break;
	
			case 0x54434F4E: // TCON -> genre
				{
					bool found = xmpObj.GetProperty ( reconProps[r].ns, reconProps[r].prop, &value, 0 );
					if ( found ) {
						std::string xmpValue = value;
						ID3_Support::GenreUtils::ConvertGenreToID3 ( xmpValue.c_str(), &value );
					}
				}
				break;

			case 0x434F4D4D: // COMM
			case 0x55534C54: // USLT, both need descriptor.
				needDescriptor = true;
				if (! xmpObj.GetProperty( reconProps[r].ns, reconProps[r].prop, &value, 0 )) value.erase();
				break;
	
			case 0x54594552: //TYER
			case 0x54444154: //TDAT
			case 0x54494D45: //TIME
				{
					if ( majorVersion <= 3 ) {	// TYER, TIME and TDAT depricated since v. 2.4 -> else use TDRC

						XMP_DateTime dateTime;
						if (! xmpObj.GetProperty_Date( reconProps[r].ns, reconProps[r].prop, &dateTime, 0 )) {	// nothing found? -> Erase string. (Leads to Unset below)
							value.erase();
							break;
						}
	
						// TYER
						if ( logicalID == 0x54594552 ) {
							XMP_Validate( dateTime.year <= 9999 && dateTime.year > 0, "Year is out of range", kXMPErr_BadParam);
							// get only Year!
							SXMPUtils::ConvertFromInt( dateTime.year, "", &value );
							break;
						} else if ( logicalID == 0x54444154 && dateTime.hasDate ) {
							std::string day, month;
							SXMPUtils::ConvertFromInt( dateTime.day, "", &day );
							SXMPUtils::ConvertFromInt( dateTime.month, "", &month );
							if ( dateTime.day < 10 )
								value = "0";
							value += day;
							if ( dateTime.month < 10 )
								value += "0";
							value += month;
							break;
						} else if ( logicalID == 0x54494D45 && dateTime.hasTime ) {
							std::string hour, minute;
							SXMPUtils::ConvertFromInt( dateTime.hour, "", &hour );
							SXMPUtils::ConvertFromInt( dateTime.minute, "", &minute );
							if ( dateTime.hour < 10 )
								value = "0";
							value += hour;
							if ( dateTime.minute < 10 )
								value += "0";
							value += minute;
							break;
						} else {
							value.erase();
							break;
						}
					} else {
						value.erase();
						break;
					}
				}
				break;
	
			case 0x54445243: //TDRC (only v2.4)
				{
					// only export for id3 > v2.4
					if ( majorVersion > 3 )  {
						if (! xmpObj.GetProperty( reconProps[r].ns, reconProps[r].prop, &value, 0 )) value.erase();
					}
					break;
				}
				break;
	
			case 0x57434F50: //WCOP
				needEncodingByte = false;
				if (! xmpObj.GetProperty( reconProps[r].ns, reconProps[r].prop, &value, 0 )) value.erase(); // if not, erase string
				break;
	
			case 0x5452434B: // TRCK
			case 0x54504F53: // TPOS
				// no break, go on:
	
			default:
				if (! xmpObj.GetProperty( reconProps[r].ns, reconProps[r].prop, &value, 0 )) value.erase(); // if not, erase string
				break;

		}

		// [XMP exist] x [frame exist] => four cases:
		// 1/4) nothing before, nothing now
		if ( value.empty() && (frame==0)) continue; // nothing to do

		// all else means there will be rewrite work to do:
		tagIsDirty = true;

		// 2/4) value before, now gone:
		if ( value.empty() && (frame!=0)) {
			frame->active = false; //mark for non-use
			continue;
		}

		// 3/4) no old value, create new value
		bool needUTF16 = false;
		if ( needEncodingByte ) needUTF16 = (! ReconcileUtils::IsASCII ( value.c_str(), value.size() ) );
		if ( frame != 0 ) {
			frame->setFrameValue( value, needDescriptor, needUTF16, false, needEncodingByte );
		} else {
			ID3v2Frame* newFrame=new ID3v2Frame( storedID );
			newFrame->setFrameValue( value, needDescriptor,  needUTF16, false, needEncodingByte ); //always write as utf16-le incl. BOM
			framesVector.push_back( newFrame );
			framesMap[ storedID ] = newFrame;
			continue;
		}

	} 	// RECON LOOP END

	/////////////////////////////////////////////////////////////////////////////////
	// (Re)Build XMP frame:

	XMP_Uns32 xmpID = XMP_V23_ID;
	if ( this->majorVersion == 2 ) xmpID = XMP_V22_ID;
	
	ID3v2Frame* frame = framesMap[ xmpID ];
	if ( frame != 0 ) {
		frame->setFrameValue( this->xmpPacket, false, false, true );
	} else {
		ID3v2Frame* newFrame=new ID3v2Frame( xmpID );
		newFrame->setFrameValue ( this->xmpPacket, false, false, true );
		framesVector.push_back ( newFrame );
		framesMap[ xmpID ] = newFrame;
	}

	////////////////////////////////////////////////////////////////////////////////
	// Decision making

	XMP_Int32 frameHeaderSize = ID3v2Frame::kV23_FrameHeaderSize;
	if ( this->majorVersion == 2 ) frameHeaderSize = ID3v2Frame::kV22_FrameHeaderSize;
	
	newFramesSize = 0;
	for ( XMP_Uns32 i = 0; i < framesVector.size(); i++ ) {
		if ( framesVector[i]->active ) newFramesSize += (frameHeaderSize + framesVector[i]->contentSize);
	}

	mustShift = (newFramesSize > (XMP_Int64)(oldTagSize - ID3Header::kID3_TagHeaderSize)) ||
	//optimization: If more than 8K can be saved by rewriting the MP3, go do it:
				((newFramesSize + 8*1024) < oldTagSize );

	if ( ! mustShift )	{	// fill what we got
		newTagSize = oldTagSize;
	} else { // if need to shift anyway, get some nice 2K padding
		newTagSize = newFramesSize + 2048 + ID3Header::kID3_TagHeaderSize;
	}
	newPadding = newTagSize - ID3Header::kID3_TagHeaderSize - newFramesSize;

	// shifting needed? -> shift
	if ( mustShift ) {
		XMP_Int64 filesize = file ->Length();
		if ( this->hasID3Tag ) {
			XIO::Move ( file, oldTagSize, file, newTagSize, filesize - oldTagSize ); //fix [2338569]
		} else {
			XIO::Move ( file, 0, file, newTagSize, filesize ); // move entire file up.
		}
	}

	// correct size stuff, write out header
	file ->Rewind();
	id3Header.write ( file, newTagSize );

	// write out tags
	for ( XMP_Uns32 i = 0; i < framesVector.size(); i++ ) {
		if ( framesVector[i]->active ) framesVector[i]->write ( file, majorVersion );
	}

	// write out padding:
	for ( XMP_Int64 i = newPadding; i > 0; ) {
		const XMP_Uns64 zero = 0;
		if ( i >= 8 ) {
			file->Write ( &zero, 8  );
			i -= 8;
			continue;
		}
		file->Write ( &zero, 1  );
		i--;
	}

	// check end of file for ID3v1 tag
	/* XMP_Int64 possibleTruncationPoint = */ file->Seek ( -128, kXMP_SeekFromEnd );
	bool alreadyHasID3v1 = (XIO::ReadInt32_BE( file ) & 0xFFFFFF00) == 0x54414700; // "TAG"
	if ( ! alreadyHasID3v1 ) file->Seek ( 128, kXMP_SeekFromEnd );	// Seek will extend the file.
	id3v1Tag.write( file, &this->xmpObj );

	this->needsUpdate = false; //do last for safety reasons

}	// MP3_MetaHandler::UpdateFile

// =================================================================================================
// MP3_MetaHandler::WriteTempFile
// ==============================

void MP3_MetaHandler::WriteTempFile ( XMP_IO* tempRef )
{
	IgnoreParam(tempRef);
	XMP_Throw ( "MP3_MetaHandler::WriteTempFile: Not supported", kXMPErr_Unimplemented );
}	// MP3_MetaHandler::WriteTempFile