//
// Copyright (c) 2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// UnrollFlatten_test.cpp:
//   Test for the outputting of [[unroll]] and [[flatten]] for the D3D compiler.
//   This test can only be enabled when HLSL support is enabled.
//

#include "GLSLANG/ShaderLang.h"
#include "angle_gl.h"
#include "common/angleutils.h"
#include "gtest/gtest.h"
#include "tests/test_utils/compiler_test.h"

using namespace sh;

namespace
{

class UnrollFlattenTest : public testing::Test
{
  public:
    UnrollFlattenTest() : mInputSpec(SH_GLES2_SPEC) {}
    UnrollFlattenTest(ShShaderSpec inputSpec) : mInputSpec(inputSpec) {}

  protected:
    void compile(const std::string &shaderString)
    {
        std::string infoLog;
        bool compilationSuccess =
            compileTestShader(GL_FRAGMENT_SHADER, mInputSpec, SH_HLSL_4_1_OUTPUT, shaderString,
                              SH_VARIABLES, &mTranslatedSource, &infoLog);
        if (!compilationSuccess)
        {
            FAIL() << "Shader compilation failed " << infoLog;
        }
        // Ignore the beginning of the shader to avoid the definitions of LOOP and FLATTEN
        mCurrentPosition = static_cast<int>(mTranslatedSource.find("cbuffer DriverConstants"));
    }

    void expect(const char *patterns[], size_t count)
    {
        const char *badPatterns[] = {UNROLL, FLATTEN};
        for (size_t i = 0; i < count; i++)
        {
            const char *pattern = patterns[i];
            auto position       = mTranslatedSource.find(pattern, mCurrentPosition);
            if (position == std::string::npos)
            {
                FAIL() << "Couldn't find '" << pattern << "' after expectations '"
                       << mExpectationList << "' in translated source:\n"
                       << mTranslatedSource;
            }

            for (size_t j = 0; j < ArraySize(badPatterns); j++)
            {
                const char *badPattern = badPatterns[j];
                if (pattern != badPattern &&
                    mTranslatedSource.find(badPattern, mCurrentPosition) < position)
                {
                    FAIL() << "Found '" << badPattern << "' before '" << pattern
                           << "' after expectations '" << mExpectationList
                           << "' in translated source:\n"
                           << mTranslatedSource;
                }
            }
            mExpectationList += " - " + std::string(pattern);
            mCurrentPosition = static_cast<int>(position) + 1;
        }
    }

    static const char *UNROLL;
    static const char *FLATTEN;

  private:
    ShShaderSpec mInputSpec;
    std::string mTranslatedSource;

    int mCurrentPosition;
    std::string mExpectationList;
};

const char *UnrollFlattenTest::UNROLL  = "LOOP";
const char *UnrollFlattenTest::FLATTEN = "FLATTEN";

// Check that the nothing is added if there is no gradient operation
// even when there is ifs and discontinuous loops
TEST_F(UnrollFlattenTest, NoGradient)
{
    const std::string &shaderString =
        "precision mediump float;\n"
        "uniform float f;\n"
        "float fun(float a){\n"           // 1
        "    if (a > 1.0) {return f;}\n"  // 2
        "    else {return a + 1.0;}\n"
        "}\n"
        "float fun2(float a){\n"                // 3
        "    for (int i = 0; i < 10; i++) {\n"  // 4
        "        if (a > 1.0) {break;}\n"       // 5
        "        a = fun(a);\n"                 // 6
        "    }\n"
        "    return a;\n"
        "}\n"
        "void main() {\n"
        "    float accum = 0.0;\n"
        "    if (f < 5.0) {accum = fun2(accum);}\n"  // 7
        "    gl_FragColor = vec4(accum);\n"
        "}\n";
    compile(shaderString);
    // 1 - shouldn't get a Lod0 version generated
    // 2 - no FLATTEN because does not contain discont loop
    // 3 - shouldn't get a Lod0 version generated
    // 4 - no LOOP because discont, and also no gradient
    // 5 - no FLATTEN because does not contain loop with a gradient
    // 6 - call non-Lod0 version
    // 7 - no FLATTEN
    const char *expectations[] = {"fun(",  "if",   "fun2(", "for", "if",
                                  "break", "fun(", "main(", "if",  "fun2("};
    expect(expectations, ArraySize(expectations));
}

// Check that when we have a gradient in a non-discontinuous loop
// we use the regular version of the functions. Also checks that
// LOOP is generated for the loop containing the gradient.
TEST_F(UnrollFlattenTest, GradientNotInDiscont)
{
    const std::string &shaderString =
        "precision mediump float;\n"
        "uniform float f;\n"
        "uniform sampler2D tex;"
        "float fun(float a){\n"                         // 1
        "    return texture2D(tex, vec2(0.5, f)).x;\n"  // 2
        "}\n"
        "float fun2(float a){\n"                        // 3
        "    for (int i = 0; i < 10; i++) {\n"          // 4
        "        if (a > 1.0) {}\n"                     // 5
        "        a = fun(a);\n"                         // 6
        "        a += texture2D(tex, vec2(a, 0.0)).x;"  // 7
        "    }\n"
        "    return a;\n"
        "}\n"
        "void main() {\n"
        "    float accum = 0.0;\n"
        "    if (f < 5.0) {accum = fun2(accum);}\n"  // 8
        "    gl_FragColor = vec4(accum);\n"
        "}\n";
    // 1 - shouldn't get a Lod0 version generated
    // 2 - no Lod0 version generated
    // 3 - shouldn't get a Lod0 version generated (not in discont loop)
    // 4 - should have LOOP because it contains a gradient operation (even if Lod0)
    // 5 - no FLATTEN because doesn't contain loop with a gradient
    // 6 - call non-Lod0 version
    // 7 - call non-Lod0 version
    // 8 - FLATTEN because it contains a loop with a gradient
    compile(shaderString);
    const char *expectations[] = {"fun(", "texture2D(", "fun2(", "LOOP",    "for", "if",
                                  "fun(", "texture2D(", "main(", "FLATTEN", "if",  "fun2("};
    expect(expectations, ArraySize(expectations));
}

// Check that when we have a gradient in a discontinuous loop
// we use the Lod0 version of the functions.
TEST_F(UnrollFlattenTest, GradientInDiscont)
{
    const std::string &shaderString =
        "precision mediump float;\n"
        "uniform float f;\n"
        "uniform sampler2D tex;"
        "float fun(float a){\n"                         // 1
        "    return texture2D(tex, vec2(0.5, f)).x;\n"  // 2
        "}\n"
        "float fun2(float a){\n"                        // 3
        "    for (int i = 0; i < 10; i++) {\n"          // 4
        "        if (a > 1.0) {break;}\n"               // 5
        "        a = fun(a);\n"                         // 6
        "        a += texture2D(tex, vec2(a, 0.0)).x;"  // 7
        "    }\n"
        "    return a;\n"
        "}\n"
        "void main() {\n"
        "    float accum = 0.0;\n"
        "    if (f < 5.0) {accum = fun2(accum);}\n"  // 8
        "    gl_FragColor = vec4(accum);\n"
        "}\n";
    // 1 - should get a Lod0 version generated (gradient + discont loop)
    // 2 - will get the Lod0 if in funLod0
    // 3 - shouldn't get a Lod0 version generated (not in discont loop)
    // 4 - should have LOOP because it contains a gradient operation (even if Lod0)
    // 5 - no FLATTEN because doesn't contain a loop with a gradient
    // 6 - call Lod0 version
    // 7 - call Lod0 version
    // 8 - FLATTEN because it contains a loop with a gradient
    compile(shaderString);
    const char *expectations[] = {
        "fun(",  "texture2D(", "funLod0(",      "texture2DLod0(", "fun2(",   "LOOP", "for",  "if",
        "break", "funLod0(",   "texture2DLod0", "main(",          "FLATTEN", "if",   "fun2("};
    expect(expectations, ArraySize(expectations));
}

class UnrollFlattenTest_ES3 : public UnrollFlattenTest
{
  public:
    UnrollFlattenTest_ES3() : UnrollFlattenTest(SH_GLES3_SPEC) {}
};

// Check that we correctly detect the ES3 builtin "texture" function as a gradient operation.
TEST_F(UnrollFlattenTest_ES3, TextureBuiltin)
{
    const std::string &shaderString =
        "#version 300 es\n"
        "precision mediump float;\n"
        "uniform sampler2D tex;"
        "out float fragColor;\n"
        "void main() {\n"
        "    float a = 0.0;"
        "    for (int i = 0; i < 10; i++) {\n"
        "        if (a > 1.0) {break;}\n"
        "        a += texture(tex, vec2(a, 0.0)).x;"
        "    }\n"
        "    fragColor = a;\n"
        "}\n";

    compile(shaderString);
    const char *expectations[] = {"main(", "LOOP", "Lod0("};
    expect(expectations, ArraySize(expectations));
}
}  // namespace
