/*
 * 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 "src/base/SkAutoMalloc.h"
#include "src/core/SkTraceEvent.h"
#include "src/gpu/PipelineUtils.h"
#include "src/gpu/ganesh/gl/GrGLGpu.h"
#include "src/gpu/ganesh/gl/builders/GrGLShaderStringBuilder.h"
#include "src/sksl/SkSLCompiler.h"
#include "src/sksl/SkSLProgramSettings.h"
#include "src/sksl/codegen/SkSLGLSLCodeGenerator.h"
#include "src/sksl/ir/SkSLProgram.h"
#include "src/utils/SkShaderUtils.h"

std::unique_ptr<SkSL::Program> GrSkSLtoGLSL(const GrGLGpu* gpu,
                                            SkSL::ProgramKind programKind,
                                            const std::string& sksl,
                                            const SkSL::ProgramSettings& settings,
                                            std::string* glsl,
                                            GrContextOptions::ShaderErrorHandler* errorHandler) {
    SkSL::Compiler* compiler = gpu->shaderCompiler();
    std::unique_ptr<SkSL::Program> program;
#ifdef SK_DEBUG
    std::string src = SkShaderUtils::PrettyPrint(sksl);
#else
    const std::string& src = sksl;
#endif
    program = compiler->convertProgram(programKind, src, settings);
    if (!program || !compiler->toGLSL(*program, glsl)) {
        errorHandler->compileError(src.c_str(), compiler->errorText().c_str());
        return nullptr;
    }

    if (skgpu::gPrintSKSL || skgpu::gPrintBackendSL) {
        SkShaderUtils::PrintShaderBanner(programKind);
        if (skgpu::gPrintSKSL) {
            SkDebugf("SKSL:\n");
            SkShaderUtils::PrintLineByLine(SkShaderUtils::PrettyPrint(sksl));
        }
        if (skgpu::gPrintBackendSL) {
            SkDebugf("GLSL:\n");
            SkShaderUtils::PrintLineByLine(SkShaderUtils::PrettyPrint(*glsl));
        }
    }

    return program;
}

GrGLuint GrGLCompileAndAttachShader(const GrGLContext& glCtx,
                                    GrGLuint programId,
                                    GrGLenum type,
                                    const std::string& glsl,
                                    GrThreadSafePipelineBuilder::Stats* stats,
                                    GrContextOptions::ShaderErrorHandler* errorHandler) {
    TRACE_EVENT0_ALWAYS("skia.shaders", "driver_compile_shader");
    const GrGLInterface* gli = glCtx.glInterface();

    // Specify GLSL source to the driver.
    GrGLuint shaderId;
    GR_GL_CALL_RET(gli, shaderId, CreateShader(type));
    if (0 == shaderId) {
        return 0;
    }
    const GrGLchar* source = glsl.c_str();
    GrGLint sourceLength = SkToInt(glsl.size());
    GR_GL_CALL(gli, ShaderSource(shaderId, 1, &source, &sourceLength));

    stats->incShaderCompilations();
    GR_GL_CALL(gli, CompileShader(shaderId));

    {
        ATRACE_ANDROID_FRAMEWORK("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()));
            }
            errorHandler->compileError(glsl.c_str(), infoLen > 0 ? (const char*)log.get() : "");
            GR_GL_CALL(gli, DeleteShader(shaderId));
            return 0;
        }
    }

    // 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;
}

bool GrGLCheckLinkStatus(const GrGLGpu* gpu,
                         GrGLuint programID,
                         GrContextOptions::ShaderErrorHandler* errorHandler,
                         const std::string* sksl[kGrShaderTypeCount],
                         const std::string glsl[kGrShaderTypeCount]) {
    const GrGLInterface* gli = gpu->glInterface();

    GrGLint linked = GR_GL_INIT_ZERO;
    GR_GL_CALL(gli, GetProgramiv(programID, GR_GL_LINK_STATUS, &linked));
    if (!linked && errorHandler) {
        std::string allShaders;
        if (sksl) {
            SkSL::String::appendf(&allShaders, "// Vertex SKSL\n%s\n"
                                               "// Fragment SKSL\n%s\n",
                                               sksl[kVertex_GrShaderType]->c_str(),
                                               sksl[kFragment_GrShaderType]->c_str());
        }
        if (glsl) {
            SkSL::String::appendf(&allShaders, "// Vertex GLSL\n%s\n"
                                               "// Fragment GLSL\n%s\n",
                                               glsl[kVertex_GrShaderType].c_str(),
                                               glsl[kFragment_GrShaderType].c_str());
        }
        GrGLint infoLen = GR_GL_INIT_ZERO;
        GR_GL_CALL(gli, GetProgramiv(programID, GR_GL_INFO_LOG_LENGTH, &infoLen));
        SkAutoMalloc log(infoLen+1);
        if (infoLen > 0) {
            // retrieve length even though we don't need it to workaround
            // bug in chrome cmd buffer param validation.
            GrGLsizei length = GR_GL_INIT_ZERO;
            GR_GL_CALL(gli, GetProgramInfoLog(programID, infoLen+1, &length, (char*)log.get()));
        }
        const char* errorMsg = (infoLen > 0) ? (const char*)log.get()
                                             : "link failed but did not provide an info log";
        errorHandler->compileError(allShaders.c_str(), errorMsg);
    }
    return SkToBool(linked);
}