#include "nvparse_errors.h"
#include "nvparse_externs.h"
#include <string.h>
#include <string>
#include <ctype.h>

#include <OgreGLPrerequisites.h>

#ifndef _WIN32
# define strnicmp strncasecmp
#endif

using namespace std;

namespace
{
	void ParseVertexProgramConstants( GLenum target, char *instring);
	GLuint LookupTrackMatrix(char *matrixName);
	GLuint LookupTrackMatrixTransform(char *matrixTransformName);
}

bool is_vcp10(const char * s)
{
	return ! strncmp(s, "!!VCP1.0", 8);
}

bool vcp10_init(char * s)
{
	static int vpinit = 0;
	
	if (vpinit == 0 )
	{
      /*
		if(! glh_init_extensions("GL_NV_vertex_program"))
		{
			errors.set("unable to initialize GL_NV_vertex_program");
			return false;
		}
		else
		{
        */
			vpinit = 1;
            /*
		}
        */
	}
	
	errors.reset();
	line_number = 1;
	
	myin = s;
	
	return true;
}

int vcp10_parse()
{
	// parse the constant declarations, setting their values in the GL.
	ParseVertexProgramConstants( GL_VERTEX_PROGRAM_NV, myin);
	return 0;
}


namespace
{
	
	//.----------------------------------------------------------------------------.
	//|   Function   : ParseVertexProgramConstants                                 |
	//|   Description: Parse and set VP1.0 constant memory based on const          |
	//|                directives.                                                 |
	//|                                                                            |
	//|   Format     : c[XX] = (x, y, z, w);    # where XXX is an integer 0-95.    | 
	//|              : c[XX] = TRACK(matrix, transform);   # track a matrix        |
	//.----------------------------------------------------------------------------.
	void ParseVertexProgramConstants(GLenum target, char *instring)
	{
		// don't overwrite the original string.
		char *tmpstring = new char[strlen(instring)+1];
		strcpy(tmpstring, instring);
		
		char lineSeparator[] = "\n";
		//char wordSeparator[] = " \t";
		char error[256];
		char dummy[256];
		char *token;
		
		//iterate over the lines in the string
		token = strtok(tmpstring, lineSeparator);
		
		// we assume the first line is the "!!VCP1.0 line".
		if (token != NULL)
		{
			token = strtok(NULL, lineSeparator);
		}
		
		int iLineCount = 1; // skip first line
		
		while (token != NULL)
		{
			iLineCount++;
			
			// if the first non-whitespace character is a #, this is a comment.  Skip.
			if (!sscanf(token, " #%s", dummy))
			{ // not a comment.  Is it a constant?
				
				// strip whitespace from the beginning of the string
				int i;
				for (i = 0; i < (int)strlen(token) && isspace(token[i]); i++);
				token += i;
				
				if (strlen(token) > 0 &&                  // this is not a blank line and
					!strnicmp(token, "c[", 2)) // the first word is of the form "c[xx]", so its a constant.
				{
					int iConstID;
					int iNumValuesAssigned;
					char c[6];
					
					iNumValuesAssigned = sscanf(token, " %c [ %d ] = %s ", &c[0], &iConstID, dummy);
					
					if (3 != iNumValuesAssigned || toupper(c[0]) != 'C')
					{  // error in constant directive.
						sprintf(error, "error at line %d \n\"%s\"\n", iLineCount, token);
						errors.set(error);
					}
					else if (!strnicmp(dummy, "track", 5))
					{ // this is a TrackMatrix directive
						char matrixName[256], matrixTransformName[256];
						
						// the series of %c's are to make sure "track(" doesn't get glommed onto the matrixName
						iNumValuesAssigned = sscanf(token, 
							" %c [ %d ] = %c%c%c%c%c ( %s %s ) ;",
							&c[0], &iConstID, &c[1], &c[2], &c[3], &c[4], &c[5],
							matrixName, matrixTransformName);
						
						if (iNumValuesAssigned < 8)
						{
							sprintf(error, "error at line %d \n\"%s\"\n", iLineCount, token);
							errors.set(error);
						}
						else
						{
							char *buffer;
							if (9 == iNumValuesAssigned)
							{
								// just need to remove any junk from the matrix names and IDs.
								buffer = strstr(matrixName, ",");
								if (buffer) 
									*buffer = 0;
								
								buffer = strstr(matrixTransformName, ")");
								if (buffer)
									*buffer = 0;
							}
							else // 8 == iNumValuesAssigned
							{
								// have to split the two names, since they both were put into the matrixName
								buffer = strstr(matrixName, ",");
								if (buffer)
								{
									strcpy(matrixTransformName, buffer + 1);
									*buffer = 0;
									// get rid of paren at end of transform name, if it is there
									buffer = strstr(matrixTransformName, ")");
									if (buffer)
										*buffer = 0;
									
								}
								else
								{
									sprintf(error, "error at line %d \n\"%s\"\n", iLineCount, token);
									errors.set(error);
								}
							}
							
							// constant ID must be modulo 4.
							if (0 != (iConstID % 4))
							{
								sprintf(error, 
									"error at line %d \n\"%s\"\n\tglTrackMatrixNV address must be modulo 4\n",
									iLineCount, token);
								errors.set(error);
							}
							else if (iConstID < 0 || iConstID > 95)
							{
								sprintf(error, 
									"error at line %d \n\"%s\"\n\tConstant address out of range\n",
									iLineCount, token);
								errors.set(error);
							}
							else
							{
								// get the enum values for the specified matrices
								GLuint iMatrixID     = LookupTrackMatrix(matrixName);
								GLuint iTransformID  = LookupTrackMatrixTransform(matrixTransformName);
								
								if (0 == iMatrixID)
								{
									sprintf(error, 
										"error at line %d \n\"%s\"\n\tInvalid Matrix parameter in glTrackMatrixNV.\n",
										iLineCount, token);
									errors.set(error);
								}
								else if (0 == iTransformID)
								{
									sprintf(error, 
										"error at line %d \n\"%s\"\n\tInvalid Transform parameter in glTrackMatrixNV\n",
										iLineCount, token);
									errors.set(error);
								}
								else
								{
									// untrack any currently tracked matrix
									glTrackMatrixNV(target, iConstID, GL_NONE, GL_IDENTITY_NV);
									
									// tell GL the matrix to track
									glTrackMatrixNV(target, iConstID, iMatrixID, iTransformID);         
								}
							}
						}
					}
					else                         // this is a constant directive
					{  
						float xyzw[4] = {0, 0, 0, 0};
						iNumValuesAssigned = sscanf(token, 
							" %c [ %d ] = ( %f , %f , %f , %f ) ; ", 
							&c[0], &iConstID, xyzw, xyzw + 1, xyzw + 2, xyzw + 3);
						
						if (6 != iNumValuesAssigned)
						{ // error in constant directive.
							sprintf(error, "error at line %d \n\"%s\"\n", iLineCount, token);
							errors.set(error);
						}
						else if (iConstID < 0 || iConstID > 95)
						{
							sprintf(error, 
								"error at line %d \n\"%s\"\n\tConstant address out of range\n",
								iLineCount, token);
							errors.set(error);
						}
						else 
						{
							// Always set the closest matrix location to tracking NONE to avoid errors!
							glTrackMatrixNV(target, iConstID - (iConstID % 4), GL_NONE, GL_IDENTITY_NV);
							
							// tell GL the constant values
							glProgramParameter4fvNV(target, iConstID, xyzw);
						}
					}
        }
      }
      
      // get the next line
      token = strtok(NULL, lineSeparator);
  }
}


struct MatrixLookupEntry
{
    string name;
    GLuint      ID; 
};


//.----------------------------------------------------------------------------.
//|   Function   : LookupTrackMatrix                                           |
//|   Description: Returns the enumerated matrix name given a valid string     |
//|                or 0 if an unknown matrix is requested.                    |
//.----------------------------------------------------------------------------.
GLuint LookupTrackMatrix(char *matrixName)
{
    static bool bFirstTime = true;
    static int iNumEntries = 14;
    static MatrixLookupEntry* matrixLookupTable = new MatrixLookupEntry[iNumEntries];
    
    if (bFirstTime) // build the lookup table
    {
        matrixLookupTable[0].name   = "GL_NONE";
        matrixLookupTable[0].ID     = GL_NONE;
        matrixLookupTable[1].name   = "GL_MODELVIEW";
        matrixLookupTable[1].ID     = GL_MODELVIEW;
        matrixLookupTable[2].name   = "GL_PROJECTION";
        matrixLookupTable[2].ID     = GL_PROJECTION;
        matrixLookupTable[3].name   = "GL_TEXTURE";
        matrixLookupTable[3].ID     = GL_TEXTURE;
        matrixLookupTable[4].name   = "GL_COLOR";
        matrixLookupTable[4].ID     = GL_COLOR;
        matrixLookupTable[5].name   = "GL_MODELVIEW_PROJECTION_NV";
        matrixLookupTable[5].ID     = GL_MODELVIEW_PROJECTION_NV;
        matrixLookupTable[6].name   = "GL_MATRIX0_NV";
        matrixLookupTable[6].ID     = GL_MATRIX0_NV;
        matrixLookupTable[7].name   = "GL_MATRIX1_NV";
        matrixLookupTable[7].ID     = GL_MATRIX1_NV;
        matrixLookupTable[8].name   = "GL_MATRIX2_NV";
        matrixLookupTable[8].ID     = GL_MATRIX2_NV;
        matrixLookupTable[9].name   = "GL_MATRIX3_NV";
        matrixLookupTable[9].ID     = GL_MATRIX3_NV;
        matrixLookupTable[10].name  = "GL_MATRIX4_NV";
        matrixLookupTable[10].ID    = GL_MATRIX4_NV;
        matrixLookupTable[11].name  = "GL_MATRIX5_NV";
        matrixLookupTable[11].ID    = GL_MATRIX5_NV;
        matrixLookupTable[12].name  = "GL_MATRIX6_NV";
        matrixLookupTable[12].ID    = GL_MATRIX6_NV;
        matrixLookupTable[13].name  = "GL_MATRIX7_NV";
        matrixLookupTable[13].ID    = GL_MATRIX7_NV;
        bFirstTime = false;
    }
    
    for (int i = 0; i < iNumEntries; i++)
    {
        if (!strcmp(matrixName, matrixLookupTable[i].name.c_str()))
        {
            
            return matrixLookupTable[i].ID;
        }
    }
    
    return 0;
}

//.----------------------------------------------------------------------------.
//|   Function   : LookupTrackMatrixTransform                                  |
//|   Description: Returns the enumerated matrix transform name given a valid  |
//|                string name or 0 if an unknown transform is requested.     |
//.----------------------------------------------------------------------------.
GLuint LookupTrackMatrixTransform(char *matrixTransformName)
{
    static bool bFirstTime = true;
    static int iNumEntries = 4;
    static MatrixLookupEntry* transformLookupTable = new MatrixLookupEntry[iNumEntries];
    
    if (bFirstTime)
    {
        transformLookupTable[0].name  = "GL_IDENTITY_NV";
        transformLookupTable[0].ID    = GL_IDENTITY_NV;
        transformLookupTable[1].name  = "GL_INVERSE_NV";
        transformLookupTable[1].ID    = GL_INVERSE_NV;
        transformLookupTable[2].name  = "GL_TRANSPOSE_NV";
        transformLookupTable[2].ID    = GL_TRANSPOSE_NV;
        transformLookupTable[3].name  = "GL_INVERSE_TRANSPOSE_NV";
        transformLookupTable[3].ID    = GL_INVERSE_TRANSPOSE_NV;
        bFirstTime = false;
    }
    
    for (int i = 0; i < iNumEntries; i++)
    {
        if (!strcmp( matrixTransformName, transformLookupTable[i].name.c_str()))
        {
            return transformLookupTable[i].ID;
        }
    }
    
    return 0;
}

}