/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "WebGLShader.h"

#include "GLSLANG/ShaderLang.h"
#include "GLContext.h"
#include "mozilla/dom/WebGLRenderingContextBinding.h"
#include "mozilla/MemoryReporting.h"
#include "nsPrintfCString.h"
#include "nsString.h"
#include "prenv.h"
#include "WebGLContext.h"
#include "WebGLObjectModel.h"
#include "WebGLShaderValidator.h"
#include "WebGLValidateStrings.h"

namespace mozilla {

// On success, writes to out_validator and out_translatedSource.
// On failure, writes to out_translationLog.
static bool Translate(const nsACString& source,
                      webgl::ShaderValidator* validator,
                      nsACString* const out_translationLog,
                      nsACString* const out_translatedSource) {
  if (!validator->ValidateAndTranslate(source.BeginReading())) {
    validator->GetInfoLog(out_translationLog);
    return false;
  }

  // Success
  validator->GetOutput(out_translatedSource);
  return true;
}

template <size_t N>
static bool SubstringStartsWith(const std::string& testStr, size_t offset,
                                const char (&refStr)[N]) {
  for (size_t i = 0; i < N - 1; i++) {
    if (testStr[offset + i] != refStr[i]) return false;
  }
  return true;
}

/* On success, writes to out_translatedSource.
 * On failure, writes to out_translationLog.
 *
 * Requirements:
 *   #version is either omitted, `#version 100`, or `version 300 es`.
 */
static bool TranslateWithoutValidation(const nsACString& sourceNS,
                                       bool isWebGL2,
                                       nsACString* const out_translationLog,
                                       nsACString* const out_translatedSource) {
  std::string source = sourceNS.BeginReading();

  size_t versionStrStart = source.find("#version");
  size_t versionStrLen;
  uint32_t glesslVersion;

  if (versionStrStart != std::string::npos) {
    static const char versionStr100[] = "#version 100\n";
    static const char versionStr300es[] = "#version 300 es\n";

    if (isWebGL2 &&
        SubstringStartsWith(source, versionStrStart, versionStr300es)) {
      glesslVersion = 300;
      versionStrLen = strlen(versionStr300es);

    } else if (SubstringStartsWith(source, versionStrStart, versionStr100)) {
      glesslVersion = 100;
      versionStrLen = strlen(versionStr100);

    } else {
      nsPrintfCString error("#version, if declared, must be %s.",
                            isWebGL2 ? "`100` or `300 es`" : "`100`");
      *out_translationLog = error;
      return false;
    }
  } else {
    versionStrStart = 0;
    versionStrLen = 0;
    glesslVersion = 100;
  }

  std::string reversionedSource = source;
  reversionedSource.erase(versionStrStart, versionStrLen);

  switch (glesslVersion) {
    case 100:
      /* According to ARB_ES2_compatibility extension glsl
       * should accept #version 100 for ES 2 shaders. */
      reversionedSource.insert(versionStrStart, "#version 100\n");
      break;
    case 300:
      reversionedSource.insert(versionStrStart, "#version 330\n");
      break;
    default:
      MOZ_CRASH("GFX: Bad `glesslVersion`.");
  }

  out_translatedSource->Assign(reversionedSource.c_str(),
                               reversionedSource.length());
  return true;
}

static void GetCompilationStatusAndLog(gl::GLContext* gl, GLuint shader,
                                       bool* const out_success,
                                       nsACString* const out_log) {
  GLint compileStatus = LOCAL_GL_FALSE;
  gl->fGetShaderiv(shader, LOCAL_GL_COMPILE_STATUS, &compileStatus);

  // It's simpler if we always get the log.
  GLint lenWithNull = 0;
  gl->fGetShaderiv(shader, LOCAL_GL_INFO_LOG_LENGTH, &lenWithNull);

  if (lenWithNull > 1) {
    // SetLength takes the length without the null.
    out_log->SetLength(lenWithNull - 1);
    gl->fGetShaderInfoLog(shader, lenWithNull, nullptr,
                          out_log->BeginWriting());
  } else {
    out_log->SetLength(0);
  }

  *out_success = (compileStatus == LOCAL_GL_TRUE);
}

////////////////////////////////////////////////////////////////////////////////

WebGLShader::WebGLShader(WebGLContext* webgl, GLenum type)
    : WebGLRefCountedObject(webgl),
      mGLName(webgl->gl->fCreateShader(type)),
      mType(type),
      mTranslationSuccessful(false),
      mCompilationSuccessful(false) {
  mContext->mShaders.insertBack(this);
}

WebGLShader::~WebGLShader() { DeleteOnce(); }

void WebGLShader::ShaderSource(const nsAString& source) {
  const char funcName[] = "shaderSource";
  nsString sourceWithoutComments;
  if (!TruncateComments(source, &sourceWithoutComments)) {
    mContext->ErrorOutOfMemory(
        "%s: Failed to alloc for empting comment contents.", funcName);
    return;
  }

  if (!ValidateGLSLPreprocString(mContext, funcName, sourceWithoutComments))
    return;

  // We checked that the source stripped of comments is in the
  // 7-bit ASCII range, so we can skip the NS_IsAscii() check.
  const NS_LossyConvertUTF16toASCII cleanSource(sourceWithoutComments);

  if (PR_GetEnv("MOZ_WEBGL_DUMP_SHADERS")) {
    printf_stderr("////////////////////////////////////////\n");
    printf_stderr("// MOZ_WEBGL_DUMP_SHADERS:\n");

    // Wow - Roll Your Own Foreach-Lines because printf_stderr has a hard-coded
    // internal size, so long strings are truncated.

    const size_t maxChunkSize = 1024 - 1;                   // -1 for null-term.
    const UniqueBuffer buf(moz_xmalloc(maxChunkSize + 1));  // +1 for null-term
    const auto bufBegin = (char*)buf.get();

    size_t chunkStart = 0;
    while (chunkStart != cleanSource.Length()) {
      const auto chunkEnd =
          std::min(chunkStart + maxChunkSize, size_t(cleanSource.Length()));
      const auto chunkSize = chunkEnd - chunkStart;

      memcpy(bufBegin, cleanSource.BeginReading() + chunkStart, chunkSize);
      bufBegin[chunkSize + 1] = '\0';

      printf_stderr("%s", bufBegin);
      chunkStart += chunkSize;
    }

    printf_stderr("////////////////////////////////////////\n");
  }

  mSource = source;
  mCleanSource = cleanSource;
}

void WebGLShader::CompileShader() {
  mValidator = nullptr;
  mTranslationSuccessful = false;
  mCompilationSuccessful = false;

  gl::GLContext* gl = mContext->gl;

  mValidator.reset(mContext->CreateShaderValidator(mType));

  bool success;
  if (mValidator) {
    success = Translate(mCleanSource, mValidator.get(), &mValidationLog,
                        &mTranslatedSource);
  } else {
    success = TranslateWithoutValidation(mCleanSource, mContext->IsWebGL2(),
                                         &mValidationLog, &mTranslatedSource);
  }

  if (!success) return;

  mTranslationSuccessful = true;

  const char* const parts[] = {mTranslatedSource.BeginReading()};
  gl->fShaderSource(mGLName, ArrayLength(parts), parts, nullptr);

  gl->fCompileShader(mGLName);

  GetCompilationStatusAndLog(gl, mGLName, &mCompilationSuccessful,
                             &mCompilationLog);
}

void WebGLShader::GetShaderInfoLog(nsAString* out) const {
  const nsCString& log =
      !mTranslationSuccessful ? mValidationLog : mCompilationLog;
  CopyASCIItoUTF16(log, *out);
}

JS::Value WebGLShader::GetShaderParameter(GLenum pname) const {
  switch (pname) {
    case LOCAL_GL_SHADER_TYPE:
      return JS::NumberValue(mType);

    case LOCAL_GL_DELETE_STATUS:
      return JS::BooleanValue(IsDeleteRequested());

    case LOCAL_GL_COMPILE_STATUS:
      return JS::BooleanValue(mCompilationSuccessful);

    default:
      mContext->ErrorInvalidEnumInfo("getShaderParameter: `pname`", pname);
      return JS::NullValue();
  }
}

void WebGLShader::GetShaderSource(nsAString* out) const {
  out->SetIsVoid(false);
  *out = mSource;
}

void WebGLShader::GetShaderTranslatedSource(nsAString* out) const {
  out->SetIsVoid(false);
  CopyASCIItoUTF16(mTranslatedSource, *out);
}

////////////////////////////////////////////////////////////////////////////////

bool WebGLShader::CanLinkTo(const WebGLShader* prev,
                            nsCString* const out_log) const {
  if (!mValidator) return true;

  return mValidator->CanLinkTo(prev->mValidator.get(), out_log);
}

size_t WebGLShader::CalcNumSamplerUniforms() const {
  if (mValidator) return mValidator->CalcNumSamplerUniforms();

  // TODO
  return 0;
}

size_t WebGLShader::NumAttributes() const {
  if (mValidator) return mValidator->NumAttributes();

  // TODO
  return 0;
}

void WebGLShader::BindAttribLocation(GLuint prog, const nsCString& userName,
                                     GLuint index) const {
  std::string userNameStr(userName.BeginReading());

  const std::string* mappedNameStr = &userNameStr;
  if (mValidator)
    mValidator->FindAttribMappedNameByUserName(userNameStr, &mappedNameStr);

  mContext->gl->fBindAttribLocation(prog, index, mappedNameStr->c_str());
}

bool WebGLShader::FindAttribUserNameByMappedName(
    const nsACString& mappedName, nsCString* const out_userName) const {
  if (!mValidator) return false;

  const std::string mappedNameStr(mappedName.BeginReading());
  const std::string* userNameStr;
  if (!mValidator->FindAttribUserNameByMappedName(mappedNameStr, &userNameStr))
    return false;

  *out_userName = userNameStr->c_str();
  return true;
}

bool WebGLShader::FindVaryingByMappedName(const nsACString& mappedName,
                                          nsCString* const out_userName,
                                          bool* const out_isArray) const {
  if (!mValidator) return false;

  const std::string mappedNameStr(mappedName.BeginReading());
  std::string userNameStr;
  if (!mValidator->FindVaryingByMappedName(mappedNameStr, &userNameStr,
                                           out_isArray))
    return false;

  *out_userName = userNameStr.c_str();
  return true;
}

bool WebGLShader::FindUniformByMappedName(const nsACString& mappedName,
                                          nsCString* const out_userName,
                                          bool* const out_isArray) const {
  if (!mValidator) return false;

  const std::string mappedNameStr(mappedName.BeginReading(),
                                  mappedName.Length());
  std::string userNameStr;
  if (!mValidator->FindUniformByMappedName(mappedNameStr, &userNameStr,
                                           out_isArray))
    return false;

  *out_userName = userNameStr.c_str();
  return true;
}

bool WebGLShader::UnmapUniformBlockName(
    const nsACString& baseMappedName, nsCString* const out_baseUserName) const {
  if (!mValidator) {
    *out_baseUserName = baseMappedName;
    return true;
  }

  return mValidator->UnmapUniformBlockName(baseMappedName, out_baseUserName);
}

void WebGLShader::EnumerateFragOutputs(
    std::map<nsCString, const nsCString>& out_FragOutputs) const {
  out_FragOutputs.clear();

  if (!mValidator) {
    return;
  }
  mValidator->EnumerateFragOutputs(out_FragOutputs);
}

void WebGLShader::MapTransformFeedbackVaryings(
    const std::vector<nsString>& varyings,
    std::vector<std::string>* out_mappedVaryings) const {
  MOZ_ASSERT(mType == LOCAL_GL_VERTEX_SHADER);
  MOZ_ASSERT(out_mappedVaryings);

  out_mappedVaryings->clear();
  out_mappedVaryings->reserve(varyings.size());

  for (const auto& wideUserName : varyings) {
    const NS_LossyConvertUTF16toASCII mozUserName(
        wideUserName);  // Don't validate here.
    const std::string userName(mozUserName.BeginReading(),
                               mozUserName.Length());
    const std::string* pMappedName = &userName;
    if (mValidator) {
      mValidator->FindVaryingMappedNameByUserName(userName, &pMappedName);
    }
    out_mappedVaryings->push_back(*pMappedName);
  }
}

////////////////////////////////////////////////////////////////////////////////
// Boilerplate

JSObject* WebGLShader::WrapObject(JSContext* js,
                                  JS::Handle<JSObject*> givenProto) {
  return dom::WebGLShaderBinding::Wrap(js, this, givenProto);
}

size_t WebGLShader::SizeOfIncludingThis(MallocSizeOf mallocSizeOf) const {
  size_t validatorSize = mValidator ? mallocSizeOf(mValidator.get()) : 0;
  return mallocSizeOf(this) +
         mSource.SizeOfExcludingThisIfUnshared(mallocSizeOf) +
         mCleanSource.SizeOfExcludingThisIfUnshared(mallocSizeOf) +
         validatorSize +
         mValidationLog.SizeOfExcludingThisIfUnshared(mallocSizeOf) +
         mTranslatedSource.SizeOfExcludingThisIfUnshared(mallocSizeOf) +
         mCompilationLog.SizeOfExcludingThisIfUnshared(mallocSizeOf);
}

void WebGLShader::Delete() {
  gl::GLContext* gl = mContext->GL();

  gl->fDeleteShader(mGLName);

  LinkedListElement<WebGLShader>::removeFrom(mContext->mShaders);
}

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(WebGLShader)

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(WebGLShader, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(WebGLShader, Release)

}  // namespace mozilla