#include "Screen.h"
#include "../GPU.h"
#include "../UserInterface/Engine/Scale.h"
#include "UserInterface/Engine/Geometry.h"
#include "Widgets/Widget.h"
#include <algorithm>

UI::Thickness Screen::safeInsets;

Screen::Screen(std::unique_ptr<UI::Widget> rootWidget) :
    rootWidget(std::move(rootWidget)),
    dirtyManager(this->rootWidget.get()),
    inputRouter(this->rootWidget.get()) {
}

Screen::~Screen() = default;

void Screen::OnActivate() {
    if (rootWidget) {
        rootWidget->SetPadding(safeInsets);
    }
}

void Screen::OnDeactivate() {
}

void Screen::SetSafeAreaInsets(const UI::Thickness& insets) {
    if (insets == safeInsets) {
        return;
    }
    safeInsets = insets;
}

void Screen::UpdateLayout(UI::Size viewportSize) {
    dirtyManager.UpdateLayout(viewportSize);
}

void Screen::ProcessPointerHover(UI::Point screenPoint) {
    inputRouter.ProcessPointerHover(screenPoint);
}

bool Screen::ProcessPointerStream(const std::shared_ptr<PointerStream>& stream) {
    return inputRouter.ProcessPointerStream(stream);
}

void Screen::Render() {
    if (rootWidget) {
        static UI::Thickness lastSafeAreaInsets;
        if (lastSafeAreaInsets != safeInsets) {
            lastSafeAreaInsets = safeInsets;
            rootWidget->SetPadding(safeInsets);
        }
        int width, height;
        SDL_GetWindowSizeInPixels(GPU::GetWindow(), &width, &height);
        UI::Size size;
        size.width = UI::PixelsToUnits(static_cast<float>(width));
        size.height = UI::PixelsToUnits(static_cast<float>(height));
        if (size != screenSize) {
            screenSize = size;
            rootWidget->MarkDirty(UI::DirtyFlags::Layout);
            UpdateLayout(size);
        }
        const uint64_t nowNanos = SDL_GetTicksNS();
        const float deltaSeconds = lastUpdateNanos == 0
            ? 0.0f
            : std::min(0.05f, static_cast<float>(nowNanos - lastUpdateNanos) / 1.0e9f);
        lastUpdateNanos = nowNanos;
        rootWidget->Update(deltaSeconds); // TODO: support update/draw only when we need to draw instead of always every frame
        rootWidget->Draw();
    }
}