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

#include "SkottieSlide.h"

#include "SkAnimTimer.h"
#include "SkCanvas.h"
#include "SkMakeUnique.h"
#include "Skottie.h"
#include "SkOSFile.h"
#include "SkOSPath.h"
#include "SkSGColor.h"
#include "SkSGDraw.h"
#include "SkSGGroup.h"
#include "SkSGRenderNode.h"
#include "SkSGScene.h"
#include "SkSGText.h"
#include "SkSGTransform.h"
#include "SkStream.h"
#include "SkTypeface.h"

#include <cmath>

static constexpr int CELL_WIDTH  = 240;
static constexpr int CELL_HEIGHT = 160;
static constexpr int COL_COUNT   = 4;
static constexpr int SPACER_X    = 12;
static constexpr int SPACER_Y    = 24;
static constexpr int MARGIN      = 8;

class SkottieSlide2::AnimationWrapper final : public sksg::RenderNode {
public:
    explicit AnimationWrapper(std::unique_ptr<skottie::Animation> anim)
        : fAnimation(std::move(anim)) {
        SkASSERT(fAnimation);
    }

    void tick(SkMSec t) {
        fAnimation->animationTick(t);
        this->invalidate();
    }

    void setShowInval(bool show) { fAnimation->setShowInval(show); }

    // Trivial sksg::Animator -> skottie::Animation tick adapter
    class ForwardingAnimator final : public sksg::Animator {
    public:
        ForwardingAnimator(sk_sp<AnimationWrapper> wrapper) : fWrapper(std::move(wrapper)) {}

    protected:
        void onTick(float t) override {
            fWrapper->tick(SkScalarRoundToInt(t));
        }

    private:
        sk_sp<AnimationWrapper> fWrapper;

        using INHERITED = sksg::Animator;
    };

protected:
    SkRect onRevalidate(sksg::InvalidationController* ic, const SkMatrix& ctm) override {
        return SkRect::MakeSize(fAnimation->size());
    }

    void onRender(SkCanvas* canvas) const override {
        fAnimation->render(canvas);
    }

private:
    const std::unique_ptr<skottie::Animation> fAnimation;

    using INHERITED = sksg::RenderNode;
};

SkottieSlide2::Rec::Rec(sk_sp<AnimationWrapper> wrapper)
    : fWrapper(std::move(wrapper)) {}

SkottieSlide2::Rec::Rec(Rec&& o) = default;

SkottieSlide2::SkottieSlide2(const SkString& path)
    : fPath(path)
{
    fName.set("skottie-dir");
}

// Build a global scene using tranformed animation fragments:
//
// [Group(root)]
//     [Transform]
//         [Group]
//             [AnimationWrapper]
//             [Draw]
//                 [Text]
//                 [Color]
//     [Transform]
//         [Group]
//             [AnimationWrapper]
//             [Draw]
//                 [Text]
//                 [Color]
//     ...
//
// Note: for now animation wrappers are also tracked externally in fAnims, for tick dispatching.

static sk_sp<sksg::RenderNode> MakeLabel(const SkString& txt,
                                         const SkRect& src,
                                         const SkMatrix& dstXform) {
    auto text = sksg::Text::Make(nullptr, txt);
    text->setFlags(SkPaint::kAntiAlias_Flag);
    text->setSize(12 / std::sqrt(dstXform.getScaleX() * dstXform.getScaleY()));
    text->setAlign(SkPaint::kCenter_Align);
    text->setPosition(SkPoint::Make(src.width() / 2, src.height() + text->getSize()));

    return sksg::Draw::Make(std::move(text), sksg::Color::Make(SK_ColorBLACK));
}

void SkottieSlide2::load(SkScalar, SkScalar) {
    SkString name;
    SkOSFile::Iter iter(fPath.c_str(), "json");

    int x = 0, y = 0;

    auto scene_root = sksg::Group::Make();
    sksg::AnimatorList scene_animators;

    while (iter.next(&name)) {
        SkString path = SkOSPath::Join(fPath.c_str(), name.c_str());
        if (auto anim  = skottie::Animation::MakeFromFile(path.c_str())) {
            const auto src = SkRect::MakeSize(anim->size()),
                       dst = SkRect::MakeXYWH(MARGIN + x * (CELL_WIDTH + SPACER_X),
                                              MARGIN + y * (CELL_HEIGHT + SPACER_Y),
                                              CELL_WIDTH, CELL_HEIGHT);
            const auto m   = SkMatrix::MakeRectToRect(src, dst, SkMatrix::kCenter_ScaleToFit);
            auto wrapper   = sk_make_sp<AnimationWrapper>(std::move(anim));
            auto group     = sksg::Group::Make();

            group->addChild(wrapper);
            group->addChild(MakeLabel(name, src, m));

            auto xform     = sksg::Transform::Make(std::move(group), m);

            scene_animators.push_back(
                skstd::make_unique<AnimationWrapper::ForwardingAnimator>(wrapper));
            scene_root->addChild(xform);
            fAnims.emplace_back(std::move(wrapper));

            if (++x == COL_COUNT) {
                x = 0;
                y += 1;
            }
        }
    }

    fScene = sksg::Scene::Make(std::move(scene_root), std::move(scene_animators));
}

void SkottieSlide2::unload() {
    fAnims.reset();
    fScene.reset();
    fTimeBase = 0;
}

SkISize SkottieSlide2::getDimensions() const {
    const int rows = (fAnims.count() + COL_COUNT - 1) / COL_COUNT;
    return {
        MARGIN + (COL_COUNT - 1) * SPACER_X + COL_COUNT * CELL_WIDTH + MARGIN,
        MARGIN + (rows - 1) * SPACER_Y + rows * CELL_HEIGHT + MARGIN,
    };
}

void SkottieSlide2::draw(SkCanvas* canvas) {
    fScene->render(canvas);
}

bool SkottieSlide2::animate(const SkAnimTimer& timer) {
    if (fTimeBase == 0) {
        // Reset the animation time.
        fTimeBase = timer.msec();
    }
    fScene->animate(timer.msec() - fTimeBase);

    return true;
}

bool SkottieSlide2::onMouse(SkScalar x, SkScalar y, sk_app::Window::InputState state,
                           uint32_t modifiers) {
    if (fTrackingCell < 0 && state == sk_app::Window::kDown_InputState) {
        fTrackingCell = this->findCell(x, y);
    }
    if (fTrackingCell >= 0 && state == sk_app::Window::kUp_InputState) {
        int index = this->findCell(x, y);
        if (fTrackingCell == index) {
            fAnims[index].fShowAnimationInval = !fAnims[index].fShowAnimationInval;
            fAnims[index].fWrapper->setShowInval(fAnims[index].fShowAnimationInval);
        }
        fTrackingCell = -1;
    }
    return fTrackingCell >= 0;
}

int SkottieSlide2::findCell(float x, float y) const {
    x -= MARGIN;
    y -= MARGIN;
    int index = -1;
    if (x >= 0 && y >= 0) {
        int ix = (int)x;
        int iy = (int)y;
        int col = ix / (CELL_WIDTH + SPACER_X);
        int row = iy / (CELL_HEIGHT + SPACER_Y);
        index = row * COL_COUNT + col;
        if (index >= fAnims.count()) {
            index = -1;
        }
    }
    return index;
}