/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrGLShaderStringBuilder.h"
#include "../GrGpuGL.h"
#include "gl/GrGLSLPrettyPrint.h"
#include "SkRTConf.h"
#include "SkTraceEvent.h"

#define GL_CALL(X) GR_GL_CALL(gpu->glInterface(), X)
#define GL_CALL_RET(R, X) GR_GL_CALL_RET(gpu->glInterface(), R, X)

SK_CONF_DECLARE(bool, c_PrintShaders, "gpu.printShaders", false,
                "Print the source code for all shaders generated.");

GrGLuint GrGLCompileAndAttachShader(const GrGLContext& glCtx,
                                    GrGLuint programId,
                                    GrGLenum type,
                                    const SkString& shaderSrc) {
    const GrGLInterface* gli = glCtx.interface();

     GrGLuint shaderId;
     GR_GL_CALL_RET(gli, shaderId, CreateShader(type));
     if (0 == shaderId) {
         return 0;
     }

 #ifdef SK_DEBUG
     SkString prettySource = GrGLSLPrettyPrint::PrettyPrintGLSL(shaderSrc, false);
     const GrGLchar* sourceStr = prettySource.c_str();
     GrGLint sourceLength = static_cast<GrGLint>(prettySource.size());
 #else
     GrGLint sourceLength = static_cast<GrGLint>(shaderSrc.size());
     const GrGLchar* sourceStr = shaderSrc.c_str();
 #endif
     GR_GL_CALL(gli, ShaderSource(shaderId, 1, &sourceStr, &sourceLength));
     GR_GL_CALL(gli, CompileShader(shaderId));

     // Calling GetShaderiv in Chromium is quite expensive. Assume success in release builds.
     bool checkCompiled = !glCtx.isChromium();
 #ifdef SK_DEBUG
     checkCompiled = true;
 #endif
     if (checkCompiled) {
         GrGLint compiled = GR_GL_INIT_ZERO;
         GR_GL_CALL(gli, GetShaderiv(shaderId, GR_GL_COMPILE_STATUS, &compiled));

         if (!compiled) {
             GrGLint infoLen = GR_GL_INIT_ZERO;
             GR_GL_CALL(gli, GetShaderiv(shaderId, GR_GL_INFO_LOG_LENGTH, &infoLen));
             SkAutoMalloc log(sizeof(char)*(infoLen+1)); // outside if for debugger
             if (infoLen > 0) {
                 // retrieve length even though we don't need it to workaround bug in Chromium cmd
                 // buffer param validation.
                 GrGLsizei length = GR_GL_INIT_ZERO;
                 GR_GL_CALL(gli, GetShaderInfoLog(shaderId, infoLen+1,
                                                  &length, (char*)log.get()));
                 GrPrintf(GrGLSLPrettyPrint::PrettyPrintGLSL(shaderSrc, true).c_str());
                 GrPrintf("\n%s", log.get());
             }
             SkDEBUGFAIL("Shader compilation failed!");
             GR_GL_CALL(gli, DeleteShader(shaderId));
             return 0;
         }
     }

     TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("skia.gpu"), "skia_gpu::GLShader",
                          TRACE_EVENT_SCOPE_THREAD, "shader", TRACE_STR_COPY(shaderSrc.c_str()));
     if (c_PrintShaders) {
         GrPrintf(GrGLSLPrettyPrint::PrettyPrintGLSL(shaderSrc, true).c_str());
         GrPrintf("\n");
     }

     // Attach the shader, but defer deletion until after we have linked the program.
     // This works around a bug in the Android emulator's GLES2 wrapper which
     // will immediately delete the shader object and free its memory even though it's
     // attached to a program, which then causes glLinkProgram to fail.
     GR_GL_CALL(gli, AttachShader(programId, shaderId));

     return shaderId;
}