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

#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkShader.h"
#include "include/core/SkSurface.h"
#include "include/effects/SkGradientShader.h"
#include "include/effects/SkImageFilters.h"
#include "include/effects/SkRuntimeEffect.h"
#include "src/effects/imagefilters/SkRuntimeImageFilter.h"
#include "tests/Test.h"

static void test_unscaled(skiatest::Reporter* reporter) {
    static const int kWidth = 10;
    static const int kHeight = 10;

    SkIRect ir = SkIRect::MakeWH(kWidth, kHeight);

    SkBitmap filterResult, paintResult;

    filterResult.allocN32Pixels(kWidth, kHeight);
    SkCanvas canvasFilter(filterResult);
    canvasFilter.clear(0x00000000);

    paintResult.allocN32Pixels(kWidth, kHeight);
    SkCanvas canvasPaint(paintResult);
    canvasPaint.clear(0x00000000);

    SkPoint center = SkPoint::Make(SkIntToScalar(5), SkIntToScalar(5));
    SkColor colors[] = {SK_ColorBLUE, SK_ColorRED, SK_ColorGREEN};
    SkScalar pos[] = {0, SK_ScalarHalf, SK_Scalar1};
    SkScalar radius = SkIntToScalar(5);

    sk_sp<SkShader> gradient = SkGradientShader::MakeRadial(
            center, radius, colors, pos, std::size(colors), SkTileMode::kClamp);

    // Test using the image filter
    {
        SkPaint paint;
        paint.setImageFilter(SkImageFilters::Shader(gradient, &ir));
        canvasFilter.drawRect(SkRect::Make(ir), paint);
    }

    // Test using the paint directly
    {
        SkPaint paint;
        paint.setShader(gradient);
        canvasPaint.drawRect(SkRect::Make(ir), paint);
    }

    // Assert that both paths yielded the same result
    for (int y = 0; y < kHeight; ++y) {
        const SkPMColor* filterPtr = filterResult.getAddr32(0, y);
        const SkPMColor* paintPtr = paintResult.getAddr32(0, y);
        for (int x = 0; x < kWidth; ++x, ++filterPtr, ++paintPtr) {
            REPORTER_ASSERT(reporter, *filterPtr == *paintPtr);
        }
    }
}

static void test_scaled(skiatest::Reporter* reporter) {
    static const int kWidth = 10;
    static const int kHeight = 10;

    SkIRect ir = SkIRect::MakeWH(kWidth, kHeight);

    SkBitmap filterResult, paintResult;

    filterResult.allocN32Pixels(kWidth, kHeight);
    SkCanvas canvasFilter(filterResult);
    canvasFilter.clear(0x00000000);

    paintResult.allocN32Pixels(kWidth, kHeight);
    SkCanvas canvasPaint(paintResult);
    canvasPaint.clear(0x00000000);

    SkPoint center = SkPoint::Make(SkIntToScalar(5), SkIntToScalar(5));
    SkColor colors[] = {SK_ColorBLUE, SK_ColorRED, SK_ColorGREEN};
    SkScalar pos[] = {0, SK_ScalarHalf, SK_Scalar1};
    SkScalar radius = SkIntToScalar(5);

    sk_sp<SkShader> gradient = SkGradientShader::MakeRadial(
        center, radius, colors, pos, std::size(colors), SkTileMode::kClamp);

    // Test using the image filter
    {
        SkPaint paint;
        paint.setImageFilter(SkImageFilters::Shader(gradient, &ir));
        canvasFilter.scale(SkIntToScalar(2), SkIntToScalar(2));
        canvasFilter.drawRect(SkRect::Make(ir), paint);
    }

    // Test using the paint directly
    {
        SkPaint paint;
        paint.setShader(gradient);
        canvasPaint.scale(SkIntToScalar(2), SkIntToScalar(2));
        canvasPaint.drawRect(SkRect::Make(ir), paint);
    }

    // Assert that both paths yielded the same result
    for (int y = 0; y < kHeight; ++y) {
        const SkPMColor* filterPtr = filterResult.getAddr32(0, y);
        const SkPMColor* paintPtr = paintResult.getAddr32(0, y);
        for (int x = 0; x < kWidth; ++x, ++filterPtr, ++paintPtr) {
            REPORTER_ASSERT(reporter, *filterPtr == *paintPtr);
        }
    }
}

DEF_TEST(PaintImageFilter, reporter) {
    test_unscaled(reporter);
    test_scaled(reporter);
}

static void test_runtime_shader(skiatest::Reporter* r, SkSurface* surface) {
    sk_sp<SkRuntimeEffect> effect = SkRuntimeEffect::MakeForShader(SkString(R"(
        uniform shader child;
        vec4 main(vec2 coord) {
            return child.eval(coord) * 0.5;
        }
    )"))
                                            .effect;
    SkRuntimeShaderBuilder builder(effect);

    // create a red image filter to feed as input into the SkImageFilters::RuntimeShader
    SkPaint redPaint;
    redPaint.setColor(SK_ColorRED);
    sk_sp<SkImageFilter> input = SkImageFilters::Paint(redPaint);

    // Create the different variations of SkImageFilters::RuntimeShader
    // All 3 variations should produce the same pixel output
    std::vector<sk_sp<SkImageFilter>> filters = {
            SkMakeRuntimeImageFilter(effect, /*uniforms=*/nullptr, input),
            SkImageFilters::RuntimeShader(builder, /*childShaderName=*/nullptr, input),
            SkImageFilters::RuntimeShader(builder, /*childShaderName=*/"child", input)};

    for (auto&& filter : filters) {
        auto canvas = surface->getCanvas();

        // clear to transparent
        SkPaint paint;
        paint.setColor(SK_ColorTRANSPARENT);
        paint.setBlendMode(SkBlendMode::kSrc);
        canvas->drawPaint(paint);

        SkPaint filterPaint;
        // the green color will be ignored by the filter within the runtime shader
        filterPaint.setColor(SK_ColorGREEN);
        filterPaint.setImageFilter(filter);
        canvas->saveLayer(nullptr, &filterPaint);
        // the blue color will be ignored by the filter because the input to the image filter is not
        // null
        canvas->drawColor(SK_ColorBLUE);
        canvas->restore();

        // This is expected to read back the half transparent red pixel produced by the image filter
        SkBitmap bitmap;
        REPORTER_ASSERT(r, bitmap.tryAllocPixels(surface->imageInfo()));
        REPORTER_ASSERT(r,
                        surface->readPixels(bitmap.info(),
                                            bitmap.getPixels(),
                                            bitmap.rowBytes(),
                                            /*srcX=*/0,
                                            /*srcY=*/0));
        SkColor color = bitmap.getColor(/*x=*/0, /*y=*/0);

        // check alpha with a small tolerance
        SkAlpha alpha = SkColorGetA(color);
        REPORTER_ASSERT(r, alpha >= 127 && alpha <= 129, "Expected: %d Actual: %d", 128, alpha);

        // check each color channel
        color = SkColorSetA(color, 255);
        REPORTER_ASSERT(r, SK_ColorRED == color, "Expected: %08x Actual: %08x", SK_ColorRED, color);
    }
}

DEF_TEST(SkRuntimeShaderImageFilter_CPU, r) {
    const SkImageInfo info = SkImageInfo::MakeN32Premul(/*width=*/1, /*height=*/1);
    sk_sp<SkSurface> surface(SkSurface::MakeRaster(info));
    test_runtime_shader(r, surface.get());
}

DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SkRuntimeShaderImageFilter_GPU, r, ctxInfo) {
    const SkImageInfo info = SkImageInfo::MakeN32Premul(/*width=*/1, /*height=*/1);
    sk_sp<SkSurface> surface(
            SkSurface::MakeRenderTarget(ctxInfo.directContext(), SkBudgeted::kNo, info));
    test_runtime_shader(r, surface.get());
}