/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SKSL_UTIL
#define SKSL_UTIL

#include <cstdarg>
#include <memory>
#include "stdlib.h"
#include "string.h"
#include "src/sksl/SkSLDefines.h"
#include "src/sksl/SkSLLexer.h"

#ifndef SKSL_STANDALONE
#include "include/core/SkTypes.h"
#if SK_SUPPORT_GPU
#include "include/gpu/GrContextOptions.h"
#include "src/gpu/GrShaderCaps.h"
#endif // SK_SUPPORT_GPU
#endif // SKSL_STANDALONE

class GrShaderCaps;

namespace SkSL {

class OutputStream;
class StringStream;

#if defined(SKSL_STANDALONE) || !SK_SUPPORT_GPU

// we're being compiled standalone, so we don't have access to caps...
enum GrGLSLGeneration {
    k110_GrGLSLGeneration,
    k130_GrGLSLGeneration,
    k140_GrGLSLGeneration,
    k150_GrGLSLGeneration,
    k330_GrGLSLGeneration,
    k400_GrGLSLGeneration,
    k420_GrGLSLGeneration,
    k310es_GrGLSLGeneration,
    k320es_GrGLSLGeneration,
};

#define SKSL_CAPS_CLASS StandaloneShaderCaps
class StandaloneShaderCaps {
public:
    GrGLSLGeneration generation() const {
        return k400_GrGLSLGeneration;
    }

    bool atan2ImplementedAsAtanYOverX() const {
        return false;
    }

    bool canUseMinAndAbsTogether() const {
        return true;
    }

    bool mustForceNegatedAtanParamToFloat() const {
        return false;
    }

    bool shaderDerivativeSupport() const {
        return true;
    }

    bool usesPrecisionModifiers() const {
        return true;
    }

    bool mustDeclareFragmentShaderOutput() const {
        return true;
    }

    bool fbFetchSupport() const {
        return true;
    }

    bool fbFetchNeedsCustomOutput() const {
        return false;
    }

    bool flatInterpolationSupport() const {
        return true;
    }

    bool noperspectiveInterpolationSupport() const {
        return true;
    }

    bool multisampleInterpolationSupport() const {
        return true;
    }

    bool sampleMaskSupport() const {
        return true;
    }

    bool externalTextureSupport() const {
        return true;
    }

    bool mustDoOpBetweenFloorAndAbs() const {
        return false;
    }

    bool mustGuardDivisionEvenAfterExplicitZeroCheck() const {
        return false;
    }

    bool inBlendModesFailRandomlyForAllZeroVec() const {
        return false;
    }

    bool mustEnableAdvBlendEqs() const {
        return false;
    }

    bool mustEnableSpecificAdvBlendEqs() const {
        return false;
    }

    bool canUseAnyFunctionInShader() const {
        return false;
    }

    bool noDefaultPrecisionForExternalSamplers() const {
        return false;
    }

    bool floatIs32Bits() const {
        return true;
    }

    bool integerSupport() const {
        return false;
    }

    bool builtinFMASupport() const {
        return true;
    }

    bool canUseDoLoops() const {
        // we define this to false in standalone so we don't use do loops while inlining in FP files
        // (which would then, being baked in, end up being used even in contexts where do loops are
        // not allowed)
        return false;
    }

    const char* shaderDerivativeExtensionString() const {
        return nullptr;
    }

    const char* fragCoordConventionsExtensionString() const {
        return nullptr;
    }

    const char* geometryShaderExtensionString() const {
        return nullptr;
    }

    const char* gsInvocationsExtensionString() const {
        return nullptr;
    }

    const char* externalTextureExtensionString() const {
        return nullptr;
    }

    const char* secondExternalTextureExtensionString() const {
        return nullptr;
    }

    const char* versionDeclString() const {
        return "";
    }

    bool gsInvocationsSupport() const {
        return true;
    }

    bool canUseFractForNegativeValues() const {
        return true;
    }

    bool canUseFragCoord() const {
        return true;
    }

    bool incompleteShortIntPrecision() const {
        return false;
    }

    bool addAndTrueToLoopCondition() const {
        return false;
    }

    bool unfoldShortCircuitAsTernary() const {
        return false;
    }

    bool emulateAbsIntFunction() const {
        return false;
    }

    bool rewriteDoWhileLoops() const {
        return false;
    }

    bool removePowWithConstantExponent() const {
        return false;
    }

    const char* fbFetchColorName() const {
        return nullptr;
    }
};

extern StandaloneShaderCaps standaloneCaps;

#else

#define SKSL_CAPS_CLASS GrShaderCaps
// Various sets of caps for use in tests
class ShaderCapsFactory {
public:
    static sk_sp<GrShaderCaps> Default() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fShaderDerivativeSupport = true;
        return result;
    }

    static sk_sp<GrShaderCaps> Version450Core() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 450 core";
        return result;
    }

    static sk_sp<GrShaderCaps> Version110() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 110";
        result->fGLSLGeneration = GrGLSLGeneration::k110_GrGLSLGeneration;
        return result;
    }

    static sk_sp<GrShaderCaps> UsesPrecisionModifiers() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fUsesPrecisionModifiers = true;
        return result;
    }

    static sk_sp<GrShaderCaps> CannotUseMinAndAbsTogether() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fCanUseMinAndAbsTogether = false;
        return result;
    }

    static sk_sp<GrShaderCaps> CannotUseFractForNegativeValues() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fCanUseFractForNegativeValues = false;
        return result;
    }

    static sk_sp<GrShaderCaps> MustForceNegatedAtanParamToFloat() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fMustForceNegatedAtanParamToFloat = true;
        return result;
    }

    static sk_sp<GrShaderCaps> ShaderDerivativeExtensionString() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fShaderDerivativeSupport = true;
        result->fShaderDerivativeExtensionString = "GL_OES_standard_derivatives";
        result->fUsesPrecisionModifiers = true;
        return result;
    }

    static sk_sp<GrShaderCaps> FragCoordsOld() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 110";
        result->fGLSLGeneration = GrGLSLGeneration::k110_GrGLSLGeneration;
        result->fFragCoordConventionsExtensionString = "GL_ARB_fragment_coord_conventions";
        return result;
    }

    static sk_sp<GrShaderCaps> FragCoordsNew() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fFragCoordConventionsExtensionString = "GL_ARB_fragment_coord_conventions";
        return result;
    }

    static sk_sp<GrShaderCaps> GeometryShaderSupport() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fGeometryShaderSupport = true;
        result->fGSInvocationsSupport = true;
        return result;
    }

    static sk_sp<GrShaderCaps> NoGSInvocationsSupport() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fGeometryShaderSupport = true;
        result->fGSInvocationsSupport = false;
        return result;
    }

    static sk_sp<GrShaderCaps> GeometryShaderExtensionString() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 310es";
        result->fGeometryShaderSupport = true;
        result->fGeometryShaderExtensionString = "GL_EXT_geometry_shader";
        result->fGSInvocationsSupport = true;
        return result;
    }

    static sk_sp<GrShaderCaps> GSInvocationsExtensionString() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fGeometryShaderSupport = true;
        result->fGSInvocationsSupport = true;
        result->fGSInvocationsExtensionString = "GL_ARB_gpu_shader5";
        return result;
    }

    static sk_sp<GrShaderCaps> VariousCaps() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fExternalTextureSupport = true;
        result->fFBFetchSupport = false;
        result->fCanUseAnyFunctionInShader = false;
        return result;
    }

    static sk_sp<GrShaderCaps> CannotUseFragCoord() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fCanUseFragCoord = false;
        return result;
    }

    static sk_sp<GrShaderCaps> IncompleteShortIntPrecision() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 310es";
        result->fUsesPrecisionModifiers = true;
        result->fIncompleteShortIntPrecision = true;
        return result;
    }

    static sk_sp<GrShaderCaps> AddAndTrueToLoopCondition() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fAddAndTrueToLoopCondition = true;
        return result;
    }

    static sk_sp<GrShaderCaps> UnfoldShortCircuitAsTernary() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fUnfoldShortCircuitAsTernary = true;
        return result;
    }

    static sk_sp<GrShaderCaps> EmulateAbsIntFunction() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fEmulateAbsIntFunction = true;
        return result;
    }

    static sk_sp<GrShaderCaps> RewriteDoWhileLoops() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fRewriteDoWhileLoops = true;
        return result;
    }

    static sk_sp<GrShaderCaps> RemovePowWithConstantExponent() {
        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
        result->fVersionDeclString = "#version 400";
        result->fRemovePowWithConstantExponent = true;
        return result;
    }

    static sk_sp<GrShaderCaps> SampleMaskSupport() {
        sk_sp<GrShaderCaps> result = Default();
        result->fSampleMaskSupport = true;
        return result;
    }
};
#endif

void write_stringstream(const StringStream& d, OutputStream& out);

// Returns true if op is '=' or any compound assignment operator ('+=', '-=', etc.)
bool is_assignment(Token::Kind op);

// Given a compound assignment operator, returns the non-assignment version of the operator (e.g.
// '+=' becomes '+')
Token::Kind remove_assignment(Token::Kind op);

NORETURN void sksl_abort();

} // namespace

#endif