//  SPDX-License-Identifier: MIT
//
//  EmulationStation Desktop Edition
//  NinePatchComponent.cpp
//
//  Breaks up an image into 3x3 patches to accomodate resizing without distortions.
//

#include "components/NinePatchComponent.h"

#include "resources/TextureResource.h"
#include "Log.h"
#include "ThemeData.h"

NinePatchComponent::NinePatchComponent(
        Window* window,
        const std::string& path,
        unsigned int edgeColor,
        unsigned int centerColor)
        : GuiComponent(window),
        mCornerSize(16, 16),
        mEdgeColor(edgeColor),
        mCenterColor(centerColor),
        mPath(path),
        mVertices(nullptr)
{
    if (!mPath.empty())
        buildVertices();
}

NinePatchComponent::~NinePatchComponent()
{
    if (mVertices != nullptr)
        delete[] mVertices;
}

void NinePatchComponent::updateColors()
{
    const unsigned int edgeColor = Renderer::convertColor(mEdgeColor);
    const unsigned int centerColor = Renderer::convertColor(mCenterColor);

    for (int i = 0; i < 6*9; ++i)
        mVertices[i].col = edgeColor;

    for (int i = 6*4; i < 6; ++i)
        mVertices[(6*4)+i].col = centerColor;
}

void NinePatchComponent::buildVertices()
{
    if (mVertices != nullptr)
        delete[] mVertices;

    mTexture = TextureResource::get(mPath);

    if (mTexture->getSize() == Vector2i::Zero()) {
        mVertices = nullptr;
        LOG(LogWarning) << "NinePatchComponent missing texture!";
        return;
    }

    mVertices = new Renderer::Vertex[6 * 9];

    const Vector2f texSize = Vector2f(static_cast<float>(mTexture->getSize().x()),
            static_cast<float>(mTexture->getSize().y()));

    const float imgSizeX[3] = { mCornerSize.x(), mSize.x() - mCornerSize.x() * 2, mCornerSize.x()};
    const float imgSizeY[3] = { mCornerSize.y(), mSize.y() - mCornerSize.y() * 2, mCornerSize.y()};
    const float imgPosX[3]  = { 0, imgSizeX[0], imgSizeX[0] + imgSizeX[1]};
    const float imgPosY[3]  = { 0, imgSizeY[0], imgSizeY[0] + imgSizeY[1]};

    // The "1 +" in posY and "-" in sizeY is to deal with texture coordinates having a bottom
    // left corner origin vs. verticies having a top left origin.
    const float texSizeX[3] = {  mCornerSize.x() / texSize.x(),  (texSize.x() - mCornerSize.x() * 2) / texSize.x(),  mCornerSize.x() / texSize.x() };
    const float texSizeY[3] = { -mCornerSize.y() / texSize.y(), -(texSize.y() - mCornerSize.y() * 2) / texSize.y(), -mCornerSize.y() / texSize.y() };
    const float texPosX[3]  = {  0,     texSizeX[0],     texSizeX[0] + texSizeX[1] };
    const float texPosY[3]  = {  1, 1 + texSizeY[0], 1 + texSizeY[0] + texSizeY[1] };

    int v = 0;

    for (int slice = 0; slice < 9; slice++) {
        const int sliceX  = slice % 3;
        const int sliceY  = slice / 3;
        const Vector2f imgPos = Vector2f(imgPosX[sliceX], imgPosY[sliceY]);
        const Vector2f imgSize = Vector2f(imgSizeX[sliceX], imgSizeY[sliceY]);
        const Vector2f texPos = Vector2f(texPosX[sliceX], texPosY[sliceY]);
        const Vector2f texSize = Vector2f(texSizeX[sliceX], texSizeY[sliceY]);

        mVertices[v + 1] = { { imgPos.x()              , imgPos.y()               }, { texPos.x(),               texPos.y()               }, 0 };
        mVertices[v + 2] = { { imgPos.x()              , imgPos.y() + imgSize.y() }, { texPos.x(),               texPos.y() + texSize.y() }, 0 };
        mVertices[v + 3] = { { imgPos.x() + imgSize.x(), imgPos.y()               }, { texPos.x() + texSize.x(), texPos.y()               }, 0 };
        mVertices[v + 4] = { { imgPos.x() + imgSize.x(), imgPos.y() + imgSize.y() }, { texPos.x() + texSize.x(), texPos.y() + texSize.y() }, 0 };

        // Round vertices.
        for (int i = 1; i < 5; ++i)
            mVertices[v + i].pos.round();

        // Make duplicates of first and last vertex so this can be rendered as a triangle strip.
        mVertices[v + 0] = mVertices[v + 1];
        mVertices[v + 5] = mVertices[v + 4];

        v += 6;
    }

    updateColors();
}

void NinePatchComponent::render(const Transform4x4f& parentTrans)
{
    if (!isVisible())
        return;

    Transform4x4f trans = parentTrans * getTransform();

    if (mTexture && mVertices != nullptr) {
        Renderer::setMatrix(trans);
        if (mOpacity < 255) {
            mVertices[0].shaders = Renderer::SHADER_OPACITY;
            mVertices[0].opacity = mOpacity / 255.0;
        }
        else if (mVertices[0].shaders & Renderer::SHADER_OPACITY) {
            // We have reached full opacity, so disable the opacity shader and set
            // the vertex opacity to 1.0.
            mVertices[0].shaders ^= Renderer::SHADER_OPACITY;
            mVertices[0].opacity = 1.0;
        }
        mTexture->bind();
        Renderer::drawTriangleStrips(&mVertices[0], 6*9, trans);
    }

    renderChildren(trans);
}

void NinePatchComponent::onSizeChanged()
{
    buildVertices();
}

const Vector2f& NinePatchComponent::getCornerSize() const
{
    return mCornerSize;
}

void NinePatchComponent::setCornerSize(int sizeX, int sizeY)
{
    mCornerSize = Vector2f(sizeX, sizeY);
    buildVertices();
}

void NinePatchComponent::fitTo(Vector2f size, Vector3f position, Vector2f padding)
{
    size += padding;
    position[0] -= padding.x() / 2;
    position[1] -= padding.y() / 2;

    setSize(size + mCornerSize * 2);
    setPosition(position.x() + Math::lerp(-mCornerSize.x(), mCornerSize.x(), mOrigin.x()),
                position.y() + Math::lerp(-mCornerSize.y(), mCornerSize.y(), mOrigin.y()));
}

void NinePatchComponent::setImagePath(const std::string& path)
{
    mPath = path;
    buildVertices();
}

void NinePatchComponent::setEdgeColor(unsigned int edgeColor)
{
    mEdgeColor = edgeColor;
    updateColors();
}

void NinePatchComponent::setCenterColor(unsigned int centerColor)
{
    mCenterColor = centerColor;
    updateColors();
}

void NinePatchComponent::applyTheme(const std::shared_ptr<ThemeData>& theme,
        const std::string& view, const std::string& element, unsigned int properties)
{
    GuiComponent::applyTheme(theme, view, element, properties);

    using namespace ThemeFlags;
    const ThemeData::ThemeElement* elem = theme->getElement(view, element, "ninepatch");

    if (!elem)
        return;

    if (properties & PATH && elem->has("path"))
        setImagePath(elem->get<std::string>("path"));
}