#include "Platform/Win32/EditorWindow.h"
#include "Platform/Win32/EditorWindowConstants.h"
#include "Platform/Win32/EditorWindowInternalState.h"
#include "Platform/Win32/EditorWindowRuntimeInternal.h"
#include "Platform/Win32/EditorWindowStyle.h"
#include "Composition/EditorShellPointerInteraction.h"
#include "State/EditorContext.h"

#include <XCEngine/UI/DrawData.h>

#include <algorithm>
#include <cstdint>
#include <sstream>
#include <utility>

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

using namespace EditorWindowInternal;
using ::XCEngine::UI::UIDrawData;
using ::XCEngine::UI::UIDrawList;
using ::XCEngine::UI::UIInputEvent;
using ::XCEngine::UI::UIInputEventType;
using ::XCEngine::UI::UIInputModifiers;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIPointerButton;
using ::XCEngine::UI::UIRect;

namespace {

std::string DescribeInputEventType(const UIInputEvent& event) {
    switch (event.type) {
    case UIInputEventType::PointerMove: return "PointerMove";
    case UIInputEventType::PointerEnter: return "PointerEnter";
    case UIInputEventType::PointerLeave: return "PointerLeave";
    case UIInputEventType::PointerButtonDown: return "PointerDown";
    case UIInputEventType::PointerButtonUp: return "PointerUp";
    case UIInputEventType::PointerWheel: return "PointerWheel";
    case UIInputEventType::KeyDown: return "KeyDown";
    case UIInputEventType::KeyUp: return "KeyUp";
    case UIInputEventType::Character: return "Character";
    case UIInputEventType::FocusGained: return "FocusGained";
    case UIInputEventType::FocusLost: return "FocusLost";
    default: return "Unknown";
    }
}

bool HasPendingPointerStateReconciliationEvent(
    const std::vector<UIInputEvent>& events) {
    for (const UIInputEvent& event : events) {
        switch (event.type) {
        case UIInputEventType::PointerMove:
        case UIInputEventType::PointerEnter:
        case UIInputEventType::PointerButtonDown:
        case UIInputEventType::PointerButtonUp:
        case UIInputEventType::PointerWheel:
        case UIInputEventType::FocusLost:
            return true;
        case UIInputEventType::PointerLeave:
        case UIInputEventType::KeyDown:
        case UIInputEventType::KeyUp:
        case UIInputEventType::Character:
        case UIInputEventType::FocusGained:
        case UIInputEventType::None:
        default:
            break;
        }
    }

    return false;
}

std::uint8_t ButtonMask(UIPointerButton button) {
    switch (button) {
    case UIPointerButton::Left: return 1u << 0u;
    case UIPointerButton::Right: return 1u << 1u;
    case UIPointerButton::Middle: return 1u << 2u;
    case UIPointerButton::X1: return 1u << 3u;
    case UIPointerButton::X2: return 1u << 4u;
    case UIPointerButton::None:
    default:
        return 0u;
    }
}

std::uint8_t ButtonMaskFromModifiers(const UIInputModifiers& modifiers) {
    std::uint8_t mask = 0u;
    if (modifiers.leftMouse) {
        mask |= ButtonMask(UIPointerButton::Left);
    }
    if (modifiers.rightMouse) {
        mask |= ButtonMask(UIPointerButton::Right);
    }
    if (modifiers.middleMouse) {
        mask |= ButtonMask(UIPointerButton::Middle);
    }
    if (modifiers.x1Mouse) {
        mask |= ButtonMask(UIPointerButton::X1);
    }
    if (modifiers.x2Mouse) {
        mask |= ButtonMask(UIPointerButton::X2);
    }
    return mask;
}

std::uint8_t ResolveExpectedShellCaptureButtons(
    const EditorShellRuntime& shellRuntime) {
    std::uint8_t expectedButtons = 0u;
    const auto& shellState = shellRuntime.GetShellInteractionState();
    const auto& dockHostState =
        shellState.workspaceInteractionState.dockHostInteractionState;
    if (dockHostState.splitterDragState.active ||
        !dockHostState.activeTabDragNodeId.empty()) {
        expectedButtons |= ButtonMask(UIPointerButton::Left);
    }

    for (const auto& panelState :
         shellState.workspaceInteractionState.composeState.panelStates) {
        const auto& inputBridgeState = panelState.viewportShellState.inputBridgeState;
        if (inputBridgeState.captured) {
            expectedButtons |= ButtonMask(inputBridgeState.captureButton);
        }
    }

    return expectedButtons;
}

} // namespace

EditorWindowFrameTransferRequests EditorWindow::RenderFrame(
    EditorContext& editorContext,
    bool globalTabDragActive) {
    if (!m_state->render.ready || m_state->window.hwnd == nullptr) {
        return {};
    }

    UINT pixelWidth = 0u;
    UINT pixelHeight = 0u;
    if (!ResolveRenderClientPixelSize(pixelWidth, pixelHeight)) {
        return {};
    }

    const float width = PixelsToDips(static_cast<float>(pixelWidth));
    const float height = PixelsToDips(static_cast<float>(pixelHeight));
    const UIRect workspaceBounds = ResolveWorkspaceBounds(width, height);

    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("XCEditorShell");
    drawList.AddFilledRect(
        UIRect(0.0f, 0.0f, width, height),
        kShellSurfaceColor);

    EditorWindowFrameTransferRequests transferRequests = {};
    if (editorContext.IsValid()) {
        transferRequests =
            RenderRuntimeFrame(editorContext, globalTabDragActive, workspaceBounds, drawList);
    } else {
        RenderInvalidFrame(editorContext, drawList);
    }

    AppendBorderlessWindowChrome(drawList, width);

    const Host::D3D12WindowRenderLoopPresentResult presentResult =
        m_state->render.windowRenderLoop.Present(drawData);
    if (!presentResult.warning.empty()) {
        LogRuntimeTrace("present", presentResult.warning);
    }

    m_state->render.autoScreenshot.CaptureIfRequested(
        m_state->render.renderer,
        drawData,
        pixelWidth,
        pixelHeight,
        presentResult.framePresented);
    return transferRequests;
}

EditorWindowFrameTransferRequests EditorWindow::OnPaintMessage(
    EditorContext& editorContext,
    bool globalTabDragActive) {
    if (!m_state->render.ready || m_state->window.hwnd == nullptr) {
        return {};
    }

    PAINTSTRUCT paintStruct = {};
    BeginPaint(m_state->window.hwnd, &paintStruct);
    const EditorWindowFrameTransferRequests transferRequests =
        RenderFrame(editorContext, globalTabDragActive);
    EndPaint(m_state->window.hwnd, &paintStruct);
    return transferRequests;
}

UIRect EditorWindow::ResolveWorkspaceBounds(float clientWidthDips, float clientHeightDips) const {
    if (!IsBorderlessWindowEnabled()) {
        return UIRect(0.0f, 0.0f, clientWidthDips, clientHeightDips);
    }

    if (ShouldUseDetachedTitleBarTabStrip()) {
        return UIRect(0.0f, 0.0f, clientWidthDips, clientHeightDips);
    }

    const float titleBarHeight = (std::min)(kBorderlessTitleBarHeightDips, clientHeightDips);
    return UIRect(
        0.0f,
        titleBarHeight,
        clientWidthDips,
        (std::max)(0.0f, clientHeightDips - titleBarHeight));
}

EditorWindowFrameTransferRequests EditorWindow::RenderRuntimeFrame(
    EditorContext& editorContext,
    bool globalTabDragActive,
    const UIRect& workspaceBounds,
    UIDrawList& drawList) {
    SyncShellCapturedPointerButtonsFromSystemState();
    std::vector<UIInputEvent> frameEvents = std::move(m_state->input.pendingEvents);
    m_state->input.pendingEvents.clear();
    if (!frameEvents.empty() && IsVerboseRuntimeTraceEnabled()) {
        LogRuntimeTrace(
            "input",
            DescribeInputEvents(frameEvents) + " | " +
                editorContext.DescribeWorkspaceState(
                    GetWorkspaceController(),
                    m_state->composition.shellRuntime.GetShellInteractionState()));
    }

    const Host::D3D12WindowRenderLoopFrameContext frameContext =
        m_state->render.windowRenderLoop.BeginFrame();
    if (!frameContext.warning.empty()) {
        LogRuntimeTrace("viewport", frameContext.warning);
    }

    editorContext.AttachTextMeasurer(m_state->render.renderer);
    const bool useDetachedTitleBarTabStrip = ShouldUseDetachedTitleBarTabStrip();
    UIEditorWorkspaceController& workspaceController = GetMutableWorkspaceController();
    m_state->composition.shellRuntime.Update(
        editorContext,
        workspaceController,
        workspaceBounds,
        frameEvents,
        BuildCaptureStatusText(),
        m_state->window.primary
            ? EditorShellVariant::Primary
            : EditorShellVariant::DetachedWindow,
        useDetachedTitleBarTabStrip,
        useDetachedTitleBarTabStrip ? kBorderlessTitleBarHeightDips : 0.0f);
    const UIEditorShellInteractionFrame& shellFrame =
        m_state->composition.shellRuntime.GetShellFrame();
    const UIEditorDockHostInteractionState& dockHostInteractionState =
        m_state->composition.shellRuntime
            .GetShellInteractionState()
            .workspaceInteractionState
            .dockHostInteractionState;

    LogFrameInteractionTrace(editorContext, frameEvents, shellFrame);
    const EditorWindowFrameTransferRequests transferRequests =
        BuildShellTransferRequests(globalTabDragActive, dockHostInteractionState, shellFrame);

    ApplyShellRuntimePointerCapture();
    for (const WorkspaceTraceEntry& entry :
         m_state->composition.shellRuntime.GetTraceEntries()) {
        LogRuntimeTrace(entry.channel, entry.message);
    }
    ApplyCurrentCursor();
    m_state->composition.shellRuntime.Append(drawList);
    if (frameContext.canRenderViewports) {
        m_state->composition.shellRuntime.RenderRequestedViewports(frameContext.renderContext);
    }
    return transferRequests;
}

void EditorWindow::RenderInvalidFrame(
    EditorContext& editorContext,
    UIDrawList& drawList) const {
    drawList.AddText(
        UIPoint(28.0f, 28.0f),
        "Editor shell asset invalid.",
        EditorWindowInternal::kShellTextColor,
        16.0f);
    drawList.AddText(
        UIPoint(28.0f, 54.0f),
        editorContext.GetValidationMessage().empty()
            ? std::string("Unknown validation error.")
            : editorContext.GetValidationMessage(),
        EditorWindowInternal::kShellMutedTextColor,
        12.0f);
}

void EditorWindow::LogFrameInteractionTrace(
    EditorContext& editorContext,
    const std::vector<UIInputEvent>& frameEvents,
    const UIEditorShellInteractionFrame& shellFrame) const {
    if (!IsVerboseRuntimeTraceEnabled() ||
        (frameEvents.empty() &&
         !shellFrame.result.workspaceResult.dockHostResult.layoutChanged &&
         !shellFrame.result.workspaceResult.dockHostResult.commandExecuted)) {
        return;
    }

    std::ostringstream frameTrace = {};
    frameTrace << "result consumed="
               << (shellFrame.result.consumed ? "true" : "false")
               << " layoutChanged="
               << (shellFrame.result.workspaceResult.dockHostResult.layoutChanged ? "true" : "false")
               << " commandExecuted="
               << (shellFrame.result.workspaceResult.dockHostResult.commandExecuted ? "true" : "false")
               << " active="
               << GetWorkspaceController().GetWorkspace().activePanelId
               << " message="
               << shellFrame.result.workspaceResult.dockHostResult.layoutResult.message;
    LogRuntimeTrace("frame", frameTrace.str());
}

EditorWindowFrameTransferRequests EditorWindow::BuildShellTransferRequests(
    bool globalTabDragActive,
    const UIEditorDockHostInteractionState& dockHostInteractionState,
    const UIEditorShellInteractionFrame& shellFrame) const {
    EditorWindowFrameTransferRequests transferRequests = {};
    POINT screenPoint = {};
    const bool hasScreenPoint = GetCursorPos(&screenPoint) != FALSE;

    if (!globalTabDragActive &&
        !dockHostInteractionState.activeTabDragNodeId.empty() &&
        !dockHostInteractionState.activeTabDragPanelId.empty() &&
        hasScreenPoint) {
        transferRequests.beginGlobalTabDrag = EditorWindowPanelTransferRequest{
            dockHostInteractionState.activeTabDragNodeId,
            dockHostInteractionState.activeTabDragPanelId,
            screenPoint,
        };
    }

    if (shellFrame.result.workspaceResult.dockHostResult.detachRequested &&
        hasScreenPoint) {
        transferRequests.detachPanel = EditorWindowPanelTransferRequest{
            shellFrame.result.workspaceResult.dockHostResult.detachedNodeId,
            shellFrame.result.workspaceResult.dockHostResult.detachedPanelId,
            screenPoint,
        };
    }

    return transferRequests;
}

std::string EditorWindow::BuildCaptureStatusText() const {
    if (m_state->render.autoScreenshot.HasPendingCapture()) {
        return "Shot pending...";
    }

    if (!m_state->render.autoScreenshot.GetLastCaptureError().empty()) {
        return TruncateText(m_state->render.autoScreenshot.GetLastCaptureError(), 38u);
    }

    if (!m_state->render.autoScreenshot.GetLastCaptureSummary().empty()) {
        return TruncateText(m_state->render.autoScreenshot.GetLastCaptureSummary(), 38u);
    }

    return {};
}

void EditorWindow::SyncShellCapturedPointerButtonsFromSystemState() {
    m_state->input.modifierTracker.SyncFromSystemState();

    const std::uint8_t expectedButtons =
        ResolveExpectedShellCaptureButtons(m_state->composition.shellRuntime);
    if (expectedButtons == 0u ||
        HasPendingPointerStateReconciliationEvent(m_state->input.pendingEvents)) {
        return;
    }

    const UIInputModifiers modifiers =
        m_state->input.modifierTracker.GetCurrentModifiers();
    if ((ButtonMaskFromModifiers(modifiers) & expectedButtons) == expectedButtons) {
        return;
    }

    QueueSyntheticPointerStateSyncEvent(modifiers);
}

void EditorWindow::ApplyShellRuntimePointerCapture() {
    const EditorShellPointerOwner owner =
        m_state->composition.shellRuntime.GetPointerOwner();
    if (IsShellPointerOwner(owner)) {
        AcquirePointerCapture(EditorWindowPointerCaptureOwner::Shell);
        return;
    }

    if (IsHostedContentPointerOwner(owner)) {
        AcquirePointerCapture(EditorWindowPointerCaptureOwner::HostedContent);
        return;
    }

    if (OwnsPointerCapture(EditorWindowPointerCaptureOwner::Shell)) {
        ReleasePointerCapture(EditorWindowPointerCaptureOwner::Shell);
    }

    if (OwnsPointerCapture(EditorWindowPointerCaptureOwner::HostedContent)) {
        ReleasePointerCapture(EditorWindowPointerCaptureOwner::HostedContent);
    }
}

std::string EditorWindow::DescribeInputEvents(
    const std::vector<UIInputEvent>& events) const {
    std::ostringstream stream = {};
    stream << "events=[";
    for (std::size_t index = 0; index < events.size(); ++index) {
        if (index > 0u) {
            stream << " | ";
        }

        const UIInputEvent& event = events[index];
        stream << DescribeInputEventType(event)
               << '@'
               << static_cast<int>(event.position.x)
               << ','
               << static_cast<int>(event.position.y);
    }
    stream << ']';
    return stream.str();
}

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