#include "pch.h"

#include "BGRATextureView.h"
#include "Clipboard.h"
#include "CoordinateSystemConversion.h"
#include "constants.h"
#include "MeasureToolOverlayUI.h"

#include <common/utils/window.h>

#include <exception>
#include <iostream>
#include <utility>
#include <vector>

namespace
{
    constexpr std::pair<bool, bool> GetHorizontalVerticalLines(MeasureToolState::Mode mode)
    {
        switch (mode)
        {
            case MeasureToolState::Mode::Cross:
                return { true, true };

            case MeasureToolState::Mode::Vertical:
                return { false, true };

            case MeasureToolState::Mode::Horizontal:
                return { true, false };

            default:
                throw std::runtime_error("Unknown MeasureToolState Mode");
        }
    }

    void CopyToClipboard(HWND window, const MeasureToolState& toolState)
    {
        std::vector<Measurement> allMeasurements;
        for (const auto& [handle, perScreen] : toolState.perScreen)
        {
            for (const auto& [_, measurement] : perScreen.prevMeasurements)
            {
                allMeasurements.push_back(measurement);
            }

            if (handle == window && perScreen.measuredEdges)
            {
                allMeasurements.push_back(*perScreen.measuredEdges);
            }
        }

        const auto [printWidth, printHeight] = GetHorizontalVerticalLines(toolState.global.mode);
        SetClipboardToMeasurements(allMeasurements, printWidth, printHeight, toolState.commonState->units);
    }

    inline std::pair<D2D_POINT_2F, D2D_POINT_2F> ComputeCrossFeetLine(D2D_POINT_2F center, const bool horizontal)
    {
        D2D_POINT_2F start = center, end = center;
        // Computing in this way to achieve pixel-perfect axial symmetry of aliased D2D lines
        if (horizontal)
        {
            start.x -= consts::FEET_HALF_LENGTH;
            end.x += consts::FEET_HALF_LENGTH + 1.f;
        }
        else
        {
            start.y -= consts::FEET_HALF_LENGTH;
            end.y += consts::FEET_HALF_LENGTH + 1.f;
        }

        return { start, end };
    }

    bool HandleCursorUp(HWND window, MeasureToolState* toolState, const POINT cursorPos)
    {
        ClipCursor(nullptr);
        CopyToClipboard(window, *toolState);

        auto& perScreen = toolState->perScreen[window];
        
        const bool shiftPress = GetKeyState(VK_SHIFT) & 0x8000;
        if (shiftPress && perScreen.measuredEdges)
        {
            perScreen.prevMeasurements.push_back(MeasureToolState::PerScreen::PrevMeasurement(cursorPos, perScreen.measuredEdges.value()));
        }

        perScreen.measuredEdges = std::nullopt;

        return !shiftPress;
    }

    void DrawMeasurement(const Measurement& measurement,
                         D2DState& d2dState,
                         bool drawFeetOnCross,
                         MeasureToolState::Mode mode,
                         POINT cursorPos,
                         const CommonState& commonState,
                         HWND window)
    {
        const auto [drawHorizontalCrossLine, drawVerticalCrossLine] = GetHorizontalVerticalLines(mode);

        const float hMeasure = measurement.Width(Measurement::Unit::Pixel);
        const float vMeasure = measurement.Height(Measurement::Unit::Pixel);

        d2dState.ToggleAliasedLinesMode(true);
        if (drawHorizontalCrossLine)
        {
            const D2D_POINT_2F hLineStart{ .x = measurement.rect.left, .y = static_cast<float>(cursorPos.y) };
            D2D_POINT_2F hLineEnd{ .x = hLineStart.x + hMeasure, .y = hLineStart.y };
            d2dState.dxgiWindowState.rt->DrawLine(hLineStart, hLineEnd, d2dState.solidBrushes[Brush::line].get());

            if (drawFeetOnCross)
            {
                // To fill all pixels which are close, we call DrawLine with end point one pixel too far, since
                // it doesn't get filled, i.e. end point of the range is excluded. However, we want to draw cross
                // feet *on* the last pixel row, so we must subtract 1px from the corresponding axis.
                hLineEnd.x -= 1.f;
                const auto [left_start, left_end] = ComputeCrossFeetLine(hLineStart, false);
                const auto [right_start, right_end] = ComputeCrossFeetLine(hLineEnd, false);
                d2dState.dxgiWindowState.rt->DrawLine(left_start, left_end, d2dState.solidBrushes[Brush::line].get());
                d2dState.dxgiWindowState.rt->DrawLine(right_start, right_end, d2dState.solidBrushes[Brush::line].get());
            }
        }

        if (drawVerticalCrossLine)
        {
            const D2D_POINT_2F vLineStart{ .x = static_cast<float>(cursorPos.x), .y = measurement.rect.top };
            D2D_POINT_2F vLineEnd{ .x = vLineStart.x, .y = vLineStart.y + vMeasure };
            d2dState.dxgiWindowState.rt->DrawLine(vLineStart, vLineEnd, d2dState.solidBrushes[Brush::line].get());

            if (drawFeetOnCross)
            {
                vLineEnd.y -= 1.f;
                const auto [top_start, top_end] = ComputeCrossFeetLine(vLineStart, true);
                const auto [bottom_start, bottom_end] = ComputeCrossFeetLine(vLineEnd, true);
                d2dState.dxgiWindowState.rt->DrawLine(top_start, top_end, d2dState.solidBrushes[Brush::line].get());
                d2dState.dxgiWindowState.rt->DrawLine(bottom_start, bottom_end, d2dState.solidBrushes[Brush::line].get());
            }
        }

        d2dState.ToggleAliasedLinesMode(false);

        OverlayBoxText text;

        const auto [crossSymbolPos, measureStringBufLen] =
            measurement.Print(text.buffer.data(),
                                text.buffer.size(),
                                drawHorizontalCrossLine,
                                drawVerticalCrossLine,
                                commonState.units);

        d2dState.DrawTextBox(text.buffer.data(),
                             measureStringBufLen,
                             crossSymbolPos,
                             D2D_POINT_2F{ static_cast<float>(cursorPos.x), static_cast<float>(cursorPos.y) },
                             true,
                             window);
    }
}

winrt::com_ptr<ID2D1Bitmap> ConvertID3D11Texture2DToD2D1Bitmap(winrt::com_ptr<ID2D1RenderTarget> rt,
                                                               const MappedTextureView* capturedScreenTexture)
{
    D2D1_BITMAP_PROPERTIES props = { .pixelFormat = rt->GetPixelFormat() };
    rt->GetDpi(&props.dpiX, &props.dpiY);
    const auto sizeF = rt->GetSize();
    winrt::com_ptr<ID2D1Bitmap> bitmap;
    auto hr = rt->CreateBitmap(D2D1::SizeU(static_cast<uint32_t>(capturedScreenTexture->view.width),
                                           static_cast<uint32_t>(capturedScreenTexture->view.height)),
                               capturedScreenTexture->view.pixels,
                               static_cast<uint32_t>(capturedScreenTexture->view.pitch * 4),
                               props,
                               bitmap.put());
    if (FAILED(hr))
        return nullptr;

    return bitmap;
}

LRESULT CALLBACK MeasureToolWndProc(HWND window, UINT message, WPARAM wparam, LPARAM lparam) noexcept
{
    switch (message)
    {
    case WM_MOUSELEAVE:
    case WM_CURSOR_LEFT_MONITOR:
    {
        if (auto state = GetWindowParam<Serialized<MeasureToolState>*>(window))
        {
            state->Access([&](MeasureToolState& s) {
                s.perScreen[window].measuredEdges = {};
            });
        }
        break;
    }
    case WM_NCHITTEST:
        return HTCLIENT;
    case WM_CREATE:
    {
        auto state = GetWindowCreateParam<Serialized<MeasureToolState>*>(lparam);
        StoreWindowParam(window, state);

#if !defined(DEBUG_OVERLAY)
        for (; ShowCursor(false) >= 0;)
            ;
#endif
        break;
    }
    case WM_ERASEBKGND:
        return 1;
    case WM_KEYUP:
        if (wparam == VK_ESCAPE)
        {
            PostMessageW(window, WM_CLOSE, {}, {});
        }
        break;
    case WM_RBUTTONUP:
    {
        PostMessageW(window, WM_CLOSE, {}, {});
        break;
    }
    case WM_LBUTTONUP:
    {
        bool shouldClose = true;

        if (auto state = GetWindowParam<Serialized<MeasureToolState>*>(window))
        {
            state->Access([&](MeasureToolState& s) {
                shouldClose = HandleCursorUp(window,
                                             &s,
                                             convert::FromSystemToWindow(window, s.commonState->cursorPosSystemSpace));
            });
        }

        if (shouldClose)
        {
            PostMessageW(window, WM_CLOSE, {}, {});
        }
        break;
    }
    case WM_MOUSEWHEEL:
        if (auto state = GetWindowParam<Serialized<MeasureToolState>*>(window))
        {
            const int8_t step = static_cast<short>(HIWORD(wparam)) < 0 ? -consts::MOUSE_WHEEL_TOLERANCE_STEP : consts::MOUSE_WHEEL_TOLERANCE_STEP;
            state->Access([step](MeasureToolState& s) {
                int wideVal = s.global.pixelTolerance;
                wideVal += step;
                s.global.pixelTolerance = static_cast<uint8_t>(std::clamp(wideVal, 0, 255));
            });
        }
        break;
    }

    return DefWindowProcW(window, message, wparam, lparam);
}

void DrawMeasureToolTick(const CommonState& commonState,
                         Serialized<MeasureToolState>& toolState,
                         HWND window,
                         D2DState& d2dState)
{
    bool continuousCapture = {};
    bool drawFeetOnCross = {};

    std::optional<Measurement> measuredEdges{};
    MeasureToolState::Mode mode = {};
    winrt::com_ptr<ID2D1Bitmap> backgroundBitmap;
    const MappedTextureView* backgroundTextureToConvert = nullptr;
    std::vector<MeasureToolState::PerScreen::PrevMeasurement> prevMeasurements;
    toolState.Read([&](const MeasureToolState& state) {
        continuousCapture = state.global.continuousCapture;
        drawFeetOnCross = state.global.drawFeetOnCross;
        mode = state.global.mode;

        if (const auto it = state.perScreen.find(window); it != end(state.perScreen))
        {
            const auto& perScreen = it->second;

            prevMeasurements = perScreen.prevMeasurements;

            if (!perScreen.measuredEdges)
            {
                return;
            }

            measuredEdges = perScreen.measuredEdges;

            if (continuousCapture)
                return;

            if (perScreen.capturedScreenBitmap)
            {
                backgroundBitmap = perScreen.capturedScreenBitmap;
            }
            else if (perScreen.capturedScreenTexture)
            {
                backgroundTextureToConvert = perScreen.capturedScreenTexture;
            }
        }
    });

    if (!measuredEdges && prevMeasurements.empty())
    {
        return;
    }

    if (!continuousCapture && !backgroundBitmap && backgroundTextureToConvert)
    {
        backgroundBitmap = ConvertID3D11Texture2DToD2D1Bitmap(d2dState.dxgiWindowState.rt, backgroundTextureToConvert);
        if (backgroundBitmap)
        {
            toolState.Access([&](MeasureToolState& state) {
                state.perScreen[window].capturedScreenTexture = {};
                state.perScreen[window].capturedScreenBitmap = backgroundBitmap;
            });
        }
    }

    if (continuousCapture || !backgroundBitmap)
    {
        d2dState.dxgiWindowState.rt->Clear();
    }

    if (!continuousCapture && backgroundBitmap)
    {
        d2dState.dxgiWindowState.rt->DrawBitmap(backgroundBitmap.get());
    }

    for (const auto& [prevCursorPos, prevMeasurement] : prevMeasurements)
    {
        DrawMeasurement(prevMeasurement, d2dState, drawFeetOnCross, mode, prevCursorPos, commonState, window);
    }

    if (measuredEdges)
    {
        const auto cursorPos = convert::FromSystemToWindow(window, commonState.cursorPosSystemSpace);
        DrawMeasurement(*measuredEdges, d2dState, drawFeetOnCross, mode, cursorPos, commonState, window);
    }
}