/*
 * Copyright 2017 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkBlendMode.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkSurface.h"
#include "include/core/SkVertices.h"
#include "src/core/SkAutoMalloc.h"
#include "src/core/SkReadBuffer.h"
#include "src/core/SkVerticesPriv.h"
#include "src/core/SkWriteBuffer.h"
#include "tests/Test.h"
#include "tools/ToolUtils.h"

#include <cstdint>

static bool equal(const SkVertices* vert0, const SkVertices* vert1) {
    SkVerticesPriv v0(vert0->priv()), v1(vert1->priv());

    if (v0.mode() != v1.mode()) {
        return false;
    }
    if (v0.vertexCount() != v1.vertexCount()) {
        return false;
    }
    if (v0.indexCount() != v1.indexCount()) {
        return false;
    }

    if (!!v0.texCoords() != !!v1.texCoords()) {
        return false;
    }
    if (!!v0.colors() != !!v1.colors()) {
        return false;
    }

    for (int i = 0; i < v0.vertexCount(); ++i) {
        if (v0.positions()[i] != v1.positions()[i]) {
            return false;
        }
        if (v0.texCoords()) {
            if (v0.texCoords()[i] != v1.texCoords()[i]) {
                return false;
            }
        }
        if (v0.colors()) {
            if (v0.colors()[i] != v1.colors()[i]) {
                return false;
            }
        }
    }
    for (int i = 0; i < v0.indexCount(); ++i) {
        if (v0.indices()[i] != v1.indices()[i]) {
            return false;
        }
    }
    return true;
}

static void self_test(const sk_sp<SkVertices>& v0, skiatest::Reporter* reporter) {
    SkBinaryWriteBuffer writer({});
    v0->priv().encode(writer);

    SkAutoMalloc buf(writer.bytesWritten());
    writer.writeToMemory(buf.get());
    SkReadBuffer reader(buf.get(), writer.bytesWritten());

    sk_sp<SkVertices> v1 = SkVerticesPriv::Decode(reader);

    REPORTER_ASSERT(reporter, v1 != nullptr);
    REPORTER_ASSERT(reporter, v0->uniqueID() != 0);
    REPORTER_ASSERT(reporter, v1->uniqueID() != 0);
    REPORTER_ASSERT(reporter, v0->uniqueID() != v1->uniqueID());
    REPORTER_ASSERT(reporter, equal(v0.get(), v1.get()));
}

DEF_TEST(Vertices, reporter) {
    int vCount = 5;
    int iCount = 9; // odd value exercises padding logic in encode()

    // color-tex tests
    const uint32_t texFlags[] = { 0, SkVertices::kHasTexCoords_BuilderFlag };
    const uint32_t colFlags[] = { 0, SkVertices::kHasColors_BuilderFlag };
    for (auto texF : texFlags) {
        for (auto colF : colFlags) {
            uint32_t flags = texF | colF;

            SkVertices::Builder builder(SkVertices::kTriangles_VertexMode, vCount, iCount, flags);

            for (int i = 0; i < vCount; ++i) {
                float x = (float)i;
                builder.positions()[i].set(x, 1);
                if (builder.texCoords()) {
                    builder.texCoords()[i].set(x, 2);
                }
                if (builder.colors()) {
                    builder.colors()[i] = SkColorSetARGB(0xFF, i, 0x80, 0);
                }
            }
            for (int i = 0; i < iCount; ++i) {
                builder.indices()[i] = i % vCount;
            }
            self_test(builder.detach(), reporter);
        }
    }

    {
        // This has the maximum number of vertices to be rewritten as indexed triangles without
        // overflowing a 16bit index.
        SkVertices::Builder builder(SkVertices::kTriangleFan_VertexMode, UINT16_MAX + 1, 0,
                                    SkVertices::kHasColors_BuilderFlag);
        REPORTER_ASSERT(reporter, builder.isValid());
    }
    {
        // This has too many to be rewritten.
        SkVertices::Builder builder(SkVertices::kTriangleFan_VertexMode, UINT16_MAX + 2, 0,
                                    SkVertices::kHasColors_BuilderFlag);
        REPORTER_ASSERT(reporter, !builder.isValid());
    }
    {
        // Only two vertices - can't be rewritten.
        SkVertices::Builder builder(SkVertices::kTriangleFan_VertexMode, 2, 0,
                                    SkVertices::kHasColors_BuilderFlag);
        REPORTER_ASSERT(reporter, !builder.isValid());
    }
    {
        // Minimum number of indices to be rewritten.
        SkVertices::Builder builder(SkVertices::kTriangleFan_VertexMode, 10, 3,
                                    SkVertices::kHasColors_BuilderFlag);
        REPORTER_ASSERT(reporter, builder.isValid());
    }
    {
        // Too few indices to be rewritten.
        SkVertices::Builder builder(SkVertices::kTriangleFan_VertexMode, 10, 2,
                                    SkVertices::kHasColors_BuilderFlag);
        REPORTER_ASSERT(reporter, !builder.isValid());
    }
}

static void fill_triangle(SkCanvas* canvas, const SkPoint pts[], SkColor c) {
    SkColor colors[] = { c, c, c };
    auto verts = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode, 3, pts, nullptr, colors);
    canvas->drawVertices(verts, SkBlendMode::kSrc, SkPaint());
}

DEF_TEST(Vertices_clipping, reporter) {
    // A very large triangle has to be geometrically clipped (since its "fast" clipping is
    // normally done in after building SkFixed coordinates). Check that we handle this.
    // (and don't assert).
    auto surf = SkSurfaces::Raster(SkImageInfo::MakeN32Premul(3, 3));

    SkPoint pts[] = { { -10, 1 }, { -10, 2 }, { 1e9f, 1.5f } };
    fill_triangle(surf->getCanvas(), pts, SK_ColorBLACK);

    ToolUtils::PixelIter iter(surf.get());
    SkIPoint loc;
    while (void* addr = iter.next(&loc)) {
        SkPMColor c = *(SkPMColor*)addr;
        if (loc.fY == 1) {
            REPORTER_ASSERT(reporter, c == 0xFF000000);
        } else {
            REPORTER_ASSERT(reporter, c == 0);
        }
    }
}

DEF_TEST(Vertices_invalid, reporter) {
    auto surf = SkSurfaces::Raster(SkImageInfo::MakeN32Premul(10, 10));

    constexpr SkPoint    verts[] = {{0, 0}, {1, 0}, {1, 1}};
    constexpr SkColor   colors[] = {SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE};
    constexpr uint16_t indices[] = {0, 1, 20000};

    {
        auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
                                             0, verts, nullptr, colors);
        REPORTER_ASSERT(reporter, !vertices);

        // should not crash
        surf->getCanvas()->drawVertices(vertices, SkBlendMode::kSrcOver, SkPaint());
    }

    {
        auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
                                             3, verts, nullptr, colors,
                                             1, indices);
        // reflects current behavior
        // TODO: should we reject invalid index counts?
        REPORTER_ASSERT(reporter, vertices);

        // should not crash
        surf->getCanvas()->drawVertices(vertices, SkBlendMode::kSrcOver, SkPaint());
    }

    {
        auto vertices = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode,
                                             3, verts, nullptr, colors,
                                             3, indices);
        REPORTER_ASSERT(reporter, vertices);

        // should not crash
        surf->getCanvas()->drawVertices(vertices, SkBlendMode::kSrcOver, SkPaint());
    }
}