//===== Copyright © 1996-2006, Valve Corporation, All rights reserved. ======//
//
// Purpose: 
//
// $Workfile:     $
// $Date:         $
// $NoKeywords: $
//===========================================================================//

#include "tier1/commandbuffer.h"
#include "tier1/utlbuffer.h"
#include "tier1/strtools.h"

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"

#define	MAX_ALIAS_NAME	32
#define MAX_COMMAND_LENGTH 1024

struct cmdalias_t
{
	cmdalias_t	*next;
	char		name[ MAX_ALIAS_NAME ];
	char		*value;
};


//-----------------------------------------------------------------------------
// Constructor, destructor
//-----------------------------------------------------------------------------
CCommandBuffer::CCommandBuffer( ) : m_Commands( 32, 32 )
{
	m_hNextCommand = m_Commands.InvalidIndex();
	m_nWaitDelayTicks = 1;
	m_nCurrentTick = 0;
	m_nLastTickToProcess = -1;
	m_nArgSBufferSize = 0;
	m_bIsProcessingCommands = false;
	m_nMaxArgSBufferLength = ARGS_BUFFER_LENGTH;
}

CCommandBuffer::~CCommandBuffer()
{
}


//-----------------------------------------------------------------------------
// Indicates how long to delay when encoutering a 'wait' command
//-----------------------------------------------------------------------------
void CCommandBuffer::SetWaitDelayTime( int nTickDelay )
{
	Assert( nTickDelay >= 0 );
	m_nWaitDelayTicks = nTickDelay;
}

	
//-----------------------------------------------------------------------------
// Specifies a max limit of the args buffer. For unittesting. Size == 0 means use default
//-----------------------------------------------------------------------------
void CCommandBuffer::LimitArgumentBufferSize( int nSize )
{
	if ( nSize > ARGS_BUFFER_LENGTH )
	{
		nSize = ARGS_BUFFER_LENGTH;
	}

	m_nMaxArgSBufferLength = ( nSize == 0 ) ? ARGS_BUFFER_LENGTH : nSize;
}

	
//-----------------------------------------------------------------------------
// Parses argv0 out of the buffer
//-----------------------------------------------------------------------------
bool CCommandBuffer::ParseArgV0( CUtlBuffer &buf, char *pArgV0, int nMaxLen, const char **pArgS )
{
	pArgV0[0] = 0;
	*pArgS = NULL;

	if ( !buf.IsValid() )
		return false;

	int	nSize = buf.ParseToken( CCommand::DefaultBreakSet(), pArgV0, nMaxLen );
	if ( ( nSize <= 0 ) || ( nMaxLen == nSize ) )
		return false;

	int nArgSLen = buf.TellMaxPut() - buf.TellGet();
	*pArgS = (nArgSLen > 0) ? (const char*)buf.PeekGet() : NULL;
	return true;
}


//-----------------------------------------------------------------------------
// Insert a command into the command queue
//-----------------------------------------------------------------------------
void CCommandBuffer::InsertCommandAtAppropriateTime( intp hCommand )
{
	intp i;
	Command_t &command = m_Commands[hCommand];
	for ( i = m_Commands.Head(); i != m_Commands.InvalidIndex(); i = m_Commands.Next(i) )
	{
		if ( m_Commands[i].m_nTick > command.m_nTick )
			break;
	}
	m_Commands.LinkBefore( i, hCommand );
}


//-----------------------------------------------------------------------------
// Insert a command into the command queue at the appropriate time
//-----------------------------------------------------------------------------
void CCommandBuffer::InsertImmediateCommand( intp hCommand )
{
	m_Commands.LinkBefore( m_hNextCommand, hCommand );
}


//-----------------------------------------------------------------------------
// Insert a command into the command queue
//-----------------------------------------------------------------------------
bool CCommandBuffer::InsertCommand( const char *pArgS, int nCommandSize, int nTick, cmd_source_t cmdSource )
{
	if ( nCommandSize >= CCommand::MaxCommandLength() )
	{
		Warning( "WARNING: Command too long... ignoring!\n%s\n", pArgS );
		return false;
	}

	// Add one for null termination
	if ( m_nArgSBufferSize + nCommandSize + 1 > m_nMaxArgSBufferLength )
	{
		Compact();
		if ( m_nArgSBufferSize + nCommandSize + 1 > m_nMaxArgSBufferLength )
			return false;
	}
	
	memcpy( &m_pArgSBuffer[m_nArgSBufferSize], pArgS, nCommandSize );
	m_pArgSBuffer[m_nArgSBufferSize + nCommandSize] = 0;
	++nCommandSize;

	intp hCommand = m_Commands.Alloc();
	Command_t &command = m_Commands[hCommand];
	command.m_nTick = nTick;
	command.m_nFirstArgS = m_nArgSBufferSize;
	command.m_nBufferSize = nCommandSize;
	command.m_source = cmdSource;

	m_nArgSBufferSize += nCommandSize;

	if ( !m_bIsProcessingCommands || ( nTick > m_nCurrentTick ) )
	{
		InsertCommandAtAppropriateTime( hCommand );
	}
	else
	{
		InsertImmediateCommand( hCommand );
	}
	return true;
}

		
//-----------------------------------------------------------------------------
// Returns the length of the next command
//-----------------------------------------------------------------------------
void CCommandBuffer::GetNextCommandLength( const char *pText, int nMaxLen, int *pCommandLength, int *pNextCommandOffset )
{
	int nCommandLength = 0;
	int nNextCommandOffset;
	bool bIsQuoted = false;
	bool bIsCommented = false;
	for ( nNextCommandOffset=0; nNextCommandOffset < nMaxLen; ++nNextCommandOffset, nCommandLength += bIsCommented ? 0 : 1 )
	{
		char c = pText[nNextCommandOffset];
		if ( !bIsCommented )
		{
			if ( c == '"' )
			{
				bIsQuoted = !bIsQuoted;
				continue;
			}

			// don't break if inside a C++ style comment
			if ( !bIsQuoted && c == '/' )
			{
				bIsCommented = ( nNextCommandOffset < nMaxLen-1 ) && pText[nNextCommandOffset+1] == '/';
				if ( bIsCommented )
				{
					++nNextCommandOffset;
					continue;
				}
			}

			// don't break if inside a quoted string
			if ( !bIsQuoted && c == ';' )
				break;	
		}

		// FIXME: This is legacy behavior; should we not break if a \n is inside a quoted string?
		if ( c == '\n' )
			break;
	}

	*pCommandLength = nCommandLength;
	*pNextCommandOffset = nNextCommandOffset;
}


//-----------------------------------------------------------------------------
// Add text to command buffer, return false if it couldn't owing to overflow
//-----------------------------------------------------------------------------
bool CCommandBuffer::AddText( const char *pText, cmd_source_t cmdSource, int nTickDelay )
{
	Assert( nTickDelay >= 0 );

	int	nLen = Q_strlen( pText );
	int nTick = m_nCurrentTick + nTickDelay;

	// Parse the text into distinct commands
	const char *pCurrentCommand = pText;
	int nOffsetToNextCommand;
	for( ; nLen > 0; nLen -= nOffsetToNextCommand+1, pCurrentCommand += nOffsetToNextCommand+1 )
	{
		// find a \n or ; line break
		int nCommandLength;
		GetNextCommandLength( pCurrentCommand, nLen, &nCommandLength, &nOffsetToNextCommand );
		if ( nCommandLength <= 0 )
			continue;

		const char *pArgS;
		char *pArgV0 = (char*)stackalloc( nCommandLength+1 );
		CUtlBuffer bufParse( pCurrentCommand, nCommandLength, CUtlBuffer::TEXT_BUFFER | CUtlBuffer::READ_ONLY ); 
		ParseArgV0( bufParse, pArgV0, nCommandLength+1, &pArgS );
		if ( pArgV0[0] == 0 )
			continue;

		// Deal with the special 'wait' command
		if ( !Q_stricmp( pArgV0, "wait" ) && IsWaitEnabled() )
		{
			int nDelay = pArgS ? atoi( pArgS ) : m_nWaitDelayTicks;
			nTick += nDelay;
			continue;
		}

		if ( !InsertCommand( pCurrentCommand, nCommandLength, nTick, cmdSource ) )
			return false;
	}

	return true;
}


//-----------------------------------------------------------------------------
// Are we in the middle of processing commands?
//-----------------------------------------------------------------------------
bool CCommandBuffer::IsProcessingCommands()
{
	return m_bIsProcessingCommands;
}
	
	
//-----------------------------------------------------------------------------
// Delays all queued commands to execute at a later time
//-----------------------------------------------------------------------------
void CCommandBuffer::DelayAllQueuedCommands( int nDelay )
{
	if ( nDelay <= 0 )
		return;

	for ( intp i = m_Commands.Head(); i != m_Commands.InvalidIndex(); i = m_Commands.Next(i) )
	{
		m_Commands[i].m_nTick += nDelay;			
	}
}

	
//-----------------------------------------------------------------------------
// Call this to begin iterating over all commands up to flCurrentTime
//-----------------------------------------------------------------------------
void CCommandBuffer::BeginProcessingCommands( int nDeltaTicks )
{
	if ( nDeltaTicks == 0 )
		return;

	Assert( !m_bIsProcessingCommands );
	m_bIsProcessingCommands = true;
	m_nLastTickToProcess = m_nCurrentTick + nDeltaTicks - 1;

	// Necessary to insert commands while commands are being processed
	m_hNextCommand = m_Commands.Head();
}


//-----------------------------------------------------------------------------
// Returns the next command
//-----------------------------------------------------------------------------
bool CCommandBuffer::DequeueNextCommand( CCommand* pCommand )
{
	pCommand->Reset();

	Assert( m_bIsProcessingCommands );
	if ( m_Commands.Count() == 0 )
		return false;

	intp nHead = m_Commands.Head();
	Command_t &command = m_Commands[ nHead ];
	if ( command.m_nTick > m_nLastTickToProcess )
		return false;

	m_nCurrentTick = command.m_nTick;

	// Copy the current command into a temp buffer
	// NOTE: This is here to avoid the pointers returned by DequeueNextCommand
	// to become invalid by calling AddText. Is there a way we can avoid the memcpy?
	if ( command.m_nBufferSize > 0 )
	{
		pCommand->Tokenize( &m_pArgSBuffer[command.m_nFirstArgS], command.m_source );
	}

	m_Commands.Remove( nHead );

	// Necessary to insert commands while commands are being processed
	m_hNextCommand = m_Commands.Head();

//	Msg("Dequeue : ");
//	for ( int i = 0; i < nArgc; ++i )
//	{
//		Msg("%s ", m_pCurrentArgv[i] ); 
//	}
//	Msg("\n");
	return true;
}

//-----------------------------------------------------------------------------
// Compacts the command buffer
//-----------------------------------------------------------------------------
void CCommandBuffer::Compact()
{
	// Compress argvbuffer + argv
	// NOTE: I'm using this choice instead of calling malloc + free
	// per command to allocate arguments because I expect to post a
	// bunch of commands but not have many delayed commands; 
	// avoiding the allocation cost seems more important that the memcpy 
	// cost here since I expect to not have much to copy.
	m_nArgSBufferSize = 0;

	char pTempBuffer[ ARGS_BUFFER_LENGTH ];
	for ( intp i = m_Commands.Head(); i != m_Commands.InvalidIndex(); i = m_Commands.Next(i) )
	{
		Command_t &command = m_Commands[ i ];

		memcpy( &pTempBuffer[m_nArgSBufferSize], &m_pArgSBuffer[command.m_nFirstArgS], command.m_nBufferSize );
		command.m_nFirstArgS = m_nArgSBufferSize;
		m_nArgSBufferSize += command.m_nBufferSize;
	}

	// NOTE: We could also store 2 buffers in the command buffer and switch
	// between the two to avoid the 2nd memcpy; but again I'm guessing the memory
	// tradeoff isn't worth it
	memcpy( m_pArgSBuffer, pTempBuffer, m_nArgSBufferSize );
}


//-----------------------------------------------------------------------------
// Call this to finish iterating over all commands
//-----------------------------------------------------------------------------
void CCommandBuffer::EndProcessingCommands()
{
	Assert( m_bIsProcessingCommands );
	m_bIsProcessingCommands = false;
	m_nCurrentTick = m_nLastTickToProcess + 1;
	m_hNextCommand = m_Commands.InvalidIndex();

	// Extract commands that are before the end time
	// NOTE: This is a bug for this to 
	intp i = m_Commands.Head();
	if ( i == m_Commands.InvalidIndex() )
	{
		m_nArgSBufferSize = 0;
		return;
	}

	while ( i != m_Commands.InvalidIndex() )
	{
		if ( m_Commands[i].m_nTick >= m_nCurrentTick )
			break;

		AssertMsgOnce( false, "CCommandBuffer::EndProcessingCommands() called before all appropriate commands were dequeued.\n" );
		int nNext = i;
		Msg( "Warning: Skipping command %s\n", &m_pArgSBuffer[ m_Commands[i].m_nFirstArgS ] );
		m_Commands.Remove( i );
		i = nNext;
	}

	Compact();
}


//-----------------------------------------------------------------------------
// Returns a handle to the next command to process
//-----------------------------------------------------------------------------
CommandHandle_t CCommandBuffer::GetNextCommandHandle()
{
	Assert( m_bIsProcessingCommands );
	return m_Commands.Head();
}