/* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN

 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 *

 * Initial Contributors:

 * Nokia Corporation - initial contribution.

 *

 * Contributors:

 *

 * Description:

 *

 */

#include "common.h"

#include "hgl.h"

#include "context.h"

#include <string.h>

DGLShader* DGLShader_create(GLuint name)

{

	if(shader == NULL)

	{

		return NULL;

	}

	shader->obj.name = name;

	shader->obj.next = NULL;

	shader->source = NULL;

	shader->length = 0;

	return shader;

}

void DGLShader_destroy(DGLShader *shader)

{

	DGLES2_ASSERT(shader != NULL);

	if(shader->source != NULL)

	{

		free(shader->source);

		shader->source = NULL;

	}

	free(shader);

}

GL_APICALL_BUILD void GL_APIENTRY glCompileShader(GLuint shader)

{

	DGLES2_ENTER();

	ctx->hgl.CompileShader(shader);

	DGLES2_LEAVE();

}

GL_APICALL_BUILD GLuint GL_APIENTRY glCreateShader(GLenum type)

{

	DGLES2_ENTER_RET(0);

	DGLES2_ERROR_IF_RET(type != GL_VERTEX_SHADER && type != GL_FRAGMENT_SHADER, GL_INVALID_ENUM, 0);

	{

		GLuint name = ctx->hgl.CreateShader(type);

		if(DGLContext_getHostError(ctx) == GL_NO_ERROR && name != 0)

		{

			DGLContext_createShader(ctx, name);

		}

		DGLES2_LEAVE_RET(name);

	}

}

GL_APICALL_BUILD void GL_APIENTRY glDeleteShader(GLuint shader)

{

	DGLES2_ENTER();

	if(shader != 0)

	{

		DGLES2_ERROR_IF(ctx->hgl.IsProgram(shader), GL_INVALID_OPERATION);

		DGLES2_ERROR_IF(!ctx->hgl.IsShader(shader), GL_INVALID_VALUE);

		ctx->hgl.DeleteShader(shader);

		if(DGLContext_getHostError(ctx) == GL_NO_ERROR)

		{

			DGLContext_destroyShader(ctx, shader);

		}

	}

	DGLES2_LEAVE();

}

GL_APICALL_BUILD void GL_APIENTRY glGetShaderiv(GLuint shader, GLenum pname, GLint* params)

{

	DGLES2_ENTER();

	DGLES2_ERROR_IF(ctx->hgl.IsProgram(shader), GL_INVALID_OPERATION);

	DGLES2_ERROR_IF(!ctx->hgl.IsShader(shader), GL_INVALID_VALUE);

	if(pname == GL_SHADER_SOURCE_LENGTH)

	{

		DGLShader* shader_obj = DGLContext_findShader(ctx, shader);

		DGLES2_ASSERT(shader_obj != NULL);

		*params = shader_obj->length + 1;

	}

	else

	{

		ctx->hgl.GetShaderiv(shader, pname, params);

	}

	DGLES2_LEAVE();

}

GL_APICALL_BUILD void GL_APIENTRY glGetShaderInfoLog(GLuint shader, GLsizei bufsize, GLsizei* length, char* infolog)

{

	DGLES2_ENTER();

	DGLES2_ERROR_IF(ctx->hgl.IsProgram(shader), GL_INVALID_OPERATION);

	DGLES2_ERROR_IF(!ctx->hgl.IsShader(shader), GL_INVALID_VALUE);

	ctx->hgl.GetShaderInfoLog(shader, bufsize, length, infolog);

	DGLES2_LEAVE();

}

GL_APICALL_BUILD void GL_APIENTRY glGetShaderPrecisionFormat(GLenum shadertype, GLenum precisiontype, GLint* range, GLint* precision)

{

	DGLES2_ENTER();

	DGLES2_ERROR_IF(shadertype != GL_VERTEX_SHADER && shadertype != GL_FRAGMENT_SHADER, GL_INVALID_ENUM);

	// Values from the GL ES and GLSL specifications.

	switch(precisiontype)

	{

		case GL_LOW_FLOAT:

		case GL_MEDIUM_FLOAT:

		case GL_HIGH_FLOAT:

			range[0] = 127;

			range[1] = 127;

			*precision = 23;

			break;

		case GL_LOW_INT:

		case GL_MEDIUM_INT:

		case GL_HIGH_INT:

			range[0] = 15;

			range[1] = 14;

			*precision = 0;

			break;

	}

	DGLES2_LEAVE();

}

GL_APICALL_BUILD void GL_APIENTRY glGetShaderSource(GLuint shader, GLsizei bufsize, GLsizei* length, char* source)

{

	DGLES2_ENTER();

	DGLES2_ERROR_IF(ctx->hgl.IsProgram(shader), GL_INVALID_OPERATION);

	DGLES2_ERROR_IF(!ctx->hgl.IsShader(shader), GL_INVALID_VALUE);

	DGLES2_ERROR_IF(bufsize < 0, GL_INVALID_VALUE);

	{

		DGLShader* shader_obj = DGLContext_findShader(ctx, shader);

		DGLES2_ASSERT(shader_obj != NULL);

		if(length != NULL)

		{

			*length = 0;

		}

		if(source != NULL)

		{

			GLsizei num_chars = shader_obj->length < bufsize - 1 ? shader_obj->length : bufsize - 1;

			if(num_chars > 0)

			{

				strncpy(source, shader_obj->source, num_chars);

				source[num_chars] = 0;

				if(length != NULL)

				{

					*length = num_chars;

				}

			}

		}

	}

	DGLES2_LEAVE();

}

GL_APICALL_BUILD GLboolean GL_APIENTRY glIsShader(GLuint shader)

{

	DGLES2_ENTER_RET(GL_FALSE);

	DGLES2_LEAVE_RET(ctx->hgl.IsShader(shader));

}

GL_APICALL_BUILD void GL_APIENTRY glReleaseShaderCompiler(void)

{

	DGLES2_ENTER();

	// No-op.

	DGLES2_LEAVE();

}

GL_APICALL_BUILD void GL_APIENTRY glShaderBinary(GLsizei n, const GLuint* shaders, GLenum binaryformat, const void* binary, GLsizei length)

{

	DGLES2_ENTER();

	// No supported formats.

	DGLES2_ERROR(GL_INVALID_ENUM);

	DGLES2_LEAVE();

}

static const char *opengl_strtok(const char *s, int *n)

{

    static char *buffer = 0;

    static int buffersize = -1;

    static const char *delim = " \t\n\r()[]{},;:";

    static const char *prev = 0;

    int cComment = 0;

    int cppComment = 0;

    if (!s) {

        if (!*prev || !*n) {

            if (buffer) {

                free(buffer);

                buffer = 0;

                buffersize = -1;

            }

            prev = 0;

            return 0;

        }

        s = prev;

    } else {

        if (buffer) {

            free(buffer);

            buffer = 0;

            buffersize = -1;

        }

		prev = s;

    }

    if( *n && *s == '/') {

        if(*(s+1) == '*') cComment = 1;

        if(*(s+1) == '/') cppComment = 1;        

    }

    if( cComment == 1 || cppComment == 1) {

        for(; *n && (cComment == 1 || cppComment == 1); s++, (*n)--) {

            if(cComment == 1 && *s == '*' && *(s+1) == '/' ) {

                cComment = 0;

            }

            if(cppComment == 1 && *s == '\n') {

                cppComment = 0;

            }

        }

    } else {

        for (; *n && strchr(delim, *s); s++, (*n)--);

    }

	if(s - prev > 0) {

		if (buffersize < s - prev) {

			buffersize = s - prev;

			if (buffer) {

				free(buffer);

			}

		}

		memcpy(buffer, prev, s - prev);

		buffer[s - prev] = 0;

		prev = s;

	} else {

		const char *e = s;

		for (; *n && *e && !strchr(delim, *e); e++, (*n)--);

		prev = e;

		if (buffersize < e - s) {

			buffersize = e - s;

			if (buffer) {

				free(buffer);

			}

		}

		memcpy(buffer, s, e - s);

		buffer[e - s] = 0;

	}

    return buffer;

}

static char* do_eglShaderPatch(char *source, int len, int *patched_len)

{

    /* DISCLAIMER: this is not a full-blown shader parser but a simple

     * implementation which tries to remove the OpenGL ES shader

     * "precision" statements and precision qualifiers "lowp", "mediump"

     * and "highp" from the specified shader source, replace built-in

	 * constants that were renamed in GLSL ES ("gl_MaxVertexUniformVectors",

	 * "gl_MaxFragmentUniformVectors" and "gl_MaxVaryingVectors")

	 * and insert a "#version 120" directive in the beginning of the source

	 * or replace an existing "#version 100" directive. */

	DGLES2_ASSERT(source != NULL);

	DGLES2_ASSERT(len >= 0);

	{

#ifndef DGLES2_ALLOW_GLSL_110

		GLboolean version_found = GL_FALSE;

#endif

		int buffer_size;

		char *patched;

		const char *p;

		*patched_len = 0;

		buffer_size = len;

		if(patched == NULL)	{

			return NULL;

		}

		p = opengl_strtok(source, &len);

		for (; p; p = opengl_strtok(0, &len)) {

			if (!strcmp(p, "lowp") || !strcmp(p, "mediump") || !strcmp(p, "highp")) {

				continue;

			} else if (!strcmp(p, "precision")) {

				do {

					p = opengl_strtok(0, &len);

				} while(p && !strchr(p, ';'));

			} else {

				int tok_len;

				if (!strcmp(p, "gl_MaxVertexUniformVectors")) {

					p = "(gl_MaxVertexUniformComponents / 4)";

				} else if (!strcmp(p, "gl_MaxFragmentUniformVectors")) {

					p = "(gl_MaxFragmentUniformComponents / 4)";

				} else if (!strcmp(p, "gl_MaxVaryingVectors")) {

					p = "(gl_MaxVaryingFloats / 4)";

				}

#ifndef DGLES2_ALLOW_GLSL_110

				else if (!strcmp(p, "#version")) {

					p = opengl_strtok(0, &len);

					if (!strcmp(p, "100")) {

						p = "#version 120";

						version_found = GL_TRUE;

					}

				} else if (!strcmp(p, "#")) {

					p = opengl_strtok(0, &len);

					if (!strcmp(p, "version")) {

						p = opengl_strtok(0, &len);

						if (!strcmp(p, "100")) {

							p = "#version 120";

							version_found = GL_TRUE;

						}

					}

				} 

#endif // !DGLES2_ALLOW_GLSL_110

				tok_len = strlen(p);

				if(*patched_len + tok_len > buffer_size) {

					buffer_size *= 2;

					if(patched == NULL) {

						return NULL;

					}

				}

				memcpy(patched + *patched_len, p, tok_len);

				*patched_len += tok_len;

			}

		}

		patched[*patched_len] = 0;

#ifndef DGLES2_ALLOW_GLSL_110

		/* add version directive is one was not found */

		if (!version_found) {

			char* new_patched;

			*patched_len += strlen("#version 120\n");

			if (new_patched == NULL) {

				return NULL;

			}

			strcpy(new_patched, "#version 120\n");

			strcat(new_patched, patched);

			free(patched);

			patched = new_patched;

		}

#endif // !DGLES2_ALLOW_GLSL_110

		{

			/* check that we don't leave dummy preprocessor lines */

			char *sp;

			for (sp = patched; *sp;) {

				for (; *sp == ' ' || *sp == '\t'; sp++);

				if (!strncmp(sp, "#define", 7)) {

					for (p = sp + 7; *p == ' ' || *p == '\t'; p++);

					if (*p == '\n' || *p == '\r' || *p == '/') {

						memset(sp, 0x20, 7);

					}

				}

				for (; *sp && *sp != '\n' && *sp != '\r'; sp++);

				for (; *sp == '\n' || *sp == '\r'; sp++);

			}

		}

		return patched;

	}

}

GL_APICALL_BUILD void GL_APIENTRY glShaderSource(GLuint shader, GLsizei count, const char** string, const GLint* length)

{

	DGLES2_ENTER();

	DGLES2_ERROR_IF(ctx->hgl.IsProgram(shader), GL_INVALID_OPERATION);

	DGLES2_ERROR_IF(!ctx->hgl.IsShader(shader), GL_INVALID_VALUE);

	DGLES2_ERROR_IF(count < 0, GL_INVALID_VALUE);

/*

#if(CONFIG_DEBUG == 1)

	Dprintf("Editing shader:\n--ORIGINAL-SHADER--\n");

	for(unsigned i = 0; i < count; ++i)

	{

		if(length)

			Dprintf("%*s", length[i], string[i]);

		else

			Dprintf("%s", string[i]);

	}

	Dprintf("---END-ORIGINAL-SHADER---\n");

#endif // !NDEBUG

	// Remove the non OpenGL 2.x compilant keywords.

	for(unsigned i = 0; i < count; ++i)

	{

		static const char* removables[] =

		{

			"precision highp float;",

			"precision mediump float;",

			"precision lowp float;",

			"highp",

			"lowp",

			"mediump",

			"precision"

		};

		length_dgl[i] = length ? length[i] : strlen(string[i]);

		memcpy(string_dgl[i], string[i], length_dgl[i]);

		string_dgl[i][length_dgl[i]] = 0;

		for(unsigned j = 0; j < sizeof(removables)/sizeof(removables[0]); ++j)

		{

			char const* p;

			while((p = strstr(string_dgl[i], removables[j])))

			{

				memmove(p, p + strlen(removables[j]), strlen(p + strlen(removables[j])) + 1);

			}

		}

	}

#if(CONFIG_DEBUG == 1)

	Dprintf("Loading shader:\n--DESKTOP-GL-SHADER--\n");

	for(unsigned i = 0; i < count; ++i)

	{

		Dprintf("%*s", length_dgl[i], string_dgl[i]);

	}

	Dprintf("---END-DESKTOP-GL-SHADER---\n");

#endif // !NDEBUG

	ctx->hgl.ShaderSource(shader, count, string_dgl, length_dgl);

	for(unsigned i = 0; i < count; ++i)

		free(string_dgl[i]);

	free(string_dgl);

	free(length_dgl);

 */

	if(count > 0 && string != NULL)

	{

		char* source = NULL;

		int total_len = 0;

		if(count > 1)

		{

			int i;

			// Concatenate the passed strings into one source string.

			for(i = 0; i < count; i++)

			{

				int len;

				if(string[i] == NULL)

				{

					continue;

				}

				if(length == NULL || length[i] < 0)

				{

					len = strlen(string[i]);

				}

				else

				{

					len = length[i];

				}

				if(len > 0)

				{

					total_len += len;

					if(source == NULL)

					{

						if(source == NULL)

						{

							DGLES2_ERROR(GL_OUT_OF_MEMORY);

						}

						source[0] = 0;

					}

					else

					{

						if(source == NULL)

						{

							DGLES2_ERROR(GL_OUT_OF_MEMORY);

						}

					}

					strncat(source, string[i], len);

				}

			}

		}

		else

		{

			source = (char*)string[0];

			if(length == NULL || length[0] < 0)

			{

				total_len = strlen(source);

			}

			else

			{

				total_len = length[0];

			}

		}

		{

			// FIXME: This will fail with real constant data!

			int patched_len;

			const GLchar* patched = do_eglShaderPatch(source, total_len, &patched_len);