#include "ProductHierarchyPanel.h"

#include "Icons/ProductBuiltInIcons.h"
#include "Panels/ProductTreeViewStyle.h"

#include <XCEditor/Collections/UIEditorTreeView.h>

#include <string>
#include <string_view>

namespace XCEngine::UI::Editor::App {

namespace {

using ::XCEngine::UI::UIDrawList;
using ::XCEngine::UI::UIInputEvent;
using ::XCEngine::UI::UIInputEventType;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIRect;
using Widgets::AppendUIEditorTreeViewBackground;
using Widgets::AppendUIEditorTreeViewForeground;

constexpr std::string_view kHierarchyPanelId = "hierarchy";

bool ContainsPoint(const UIRect& rect, const UIPoint& point) {
    return point.x >= rect.x &&
        point.x <= rect.x + rect.width &&
        point.y >= rect.y &&
        point.y <= rect.y + rect.height;
}

std::vector<UIInputEvent> FilterHierarchyInputEvents(
    const UIRect& bounds,
    const std::vector<UIInputEvent>& inputEvents,
    bool allowInteraction,
    bool panelActive) {
    if (!allowInteraction) {
        return {};
    }

    std::vector<UIInputEvent> filteredEvents = {};
    filteredEvents.reserve(inputEvents.size());
    for (const UIInputEvent& event : inputEvents) {
        switch (event.type) {
        case UIInputEventType::PointerMove:
        case UIInputEventType::PointerButtonDown:
        case UIInputEventType::PointerButtonUp:
        case UIInputEventType::PointerWheel:
            if (ContainsPoint(bounds, event.position)) {
                filteredEvents.push_back(event);
            }
            break;
        case UIInputEventType::PointerLeave:
            filteredEvents.push_back(event);
            break;
        case UIInputEventType::FocusGained:
        case UIInputEventType::FocusLost:
        case UIInputEventType::KeyDown:
        case UIInputEventType::KeyUp:
        case UIInputEventType::Character:
            if (panelActive) {
                filteredEvents.push_back(event);
            }
            break;
        default:
            break;
        }
    }

    return filteredEvents;
}

::XCEngine::UI::UITextureHandle ResolveGameObjectIcon(
    const ProductBuiltInIcons* icons) {
    return icons != nullptr
        ? icons->Resolve(ProductBuiltInIconKind::GameObject)
        : ::XCEngine::UI::UITextureHandle {};
}

} // namespace

void ProductHierarchyPanel::Initialize() {
    RebuildItems();
}

void ProductHierarchyPanel::SetBuiltInIcons(const ProductBuiltInIcons* icons) {
    m_icons = icons;
    RebuildItems();
}

const UIEditorPanelContentHostPanelState* ProductHierarchyPanel::FindMountedHierarchyPanel(
    const UIEditorPanelContentHostFrame& contentHostFrame) const {
    for (const UIEditorPanelContentHostPanelState& panelState : contentHostFrame.panelStates) {
        if (panelState.panelId == kHierarchyPanelId && panelState.mounted) {
            return &panelState;
        }
    }

    return nullptr;
}

void ProductHierarchyPanel::RebuildItems() {
    const auto icon = ResolveGameObjectIcon(m_icons);
    const std::string previousSelection =
        m_selection.HasSelection() ? m_selection.GetSelectedId() : std::string();

    m_treeItems = {
        { "main-camera", "Main Camera", 0u, true, 0.0f, icon },
        { "directional-light", "Directional Light", 0u, true, 0.0f, icon },
        { "player", "Player", 0u, false, 0.0f, icon },
        { "player/camera-pivot", "Camera Pivot", 1u, true, 0.0f, icon },
        { "player/mesh", "Mesh", 1u, true, 0.0f, icon },
        { "environment", "Environment", 0u, false, 0.0f, icon },
        { "environment/ground", "Ground", 1u, true, 0.0f, icon },
        { "environment/props", "Props", 1u, false, 0.0f, icon },
        { "environment/props/crate-01", "Crate_01", 2u, true, 0.0f, icon },
        { "environment/props/barrel-01", "Barrel_01", 2u, true, 0.0f, icon }
    };

    m_expansion.Expand("player");
    m_expansion.Expand("environment");
    m_expansion.Expand("environment/props");

    if (!previousSelection.empty()) {
        for (const Widgets::UIEditorTreeViewItem& item : m_treeItems) {
            if (item.itemId == previousSelection) {
                m_selection.SetSelection(previousSelection);
                return;
            }
        }
    }

    if (!m_treeItems.empty()) {
        m_selection.SetSelection(m_treeItems.front().itemId);
    }
}

void ProductHierarchyPanel::Update(
    const UIEditorPanelContentHostFrame& contentHostFrame,
    const std::vector<UIInputEvent>& inputEvents,
    bool allowInteraction,
    bool panelActive) {
    const UIEditorPanelContentHostPanelState* panelState =
        FindMountedHierarchyPanel(contentHostFrame);
    if (panelState == nullptr) {
        m_visible = false;
        m_treeFrame = {};
        return;
    }

    if (m_treeItems.empty()) {
        RebuildItems();
    }

    m_visible = true;
    m_treeFrame = UpdateUIEditorTreeViewInteraction(
        m_treeInteractionState,
        m_selection,
        m_expansion,
        panelState->bounds,
        m_treeItems,
        FilterHierarchyInputEvents(panelState->bounds, inputEvents, allowInteraction, panelActive),
        BuildProductTreeViewMetrics());
}

void ProductHierarchyPanel::Append(UIDrawList& drawList) const {
    if (!m_visible || m_treeFrame.layout.bounds.width <= 0.0f || m_treeFrame.layout.bounds.height <= 0.0f) {
        return;
    }

    const Widgets::UIEditorTreeViewPalette palette = BuildProductTreeViewPalette();
    const Widgets::UIEditorTreeViewMetrics metrics = BuildProductTreeViewMetrics();
    AppendUIEditorTreeViewBackground(
        drawList,
        m_treeFrame.layout,
        m_treeItems,
        m_selection,
        m_treeInteractionState.treeViewState,
        palette,
        metrics);
    AppendUIEditorTreeViewForeground(
        drawList,
        m_treeFrame.layout,
        m_treeItems,
        palette,
        metrics);
}

} // namespace XCEngine::UI::Editor::App