#include "pch.h"
#include "util.h"

#include <common/display/dpi_aware.h>
#include <common/logger/logger.h>
#include <common/utils/process_path.h>
#include <common/utils/window.h>
#include <common/utils/excluded_apps.h>

#include <array>
#include <complex>

#include <common/display/dpi_aware.h>

#include <FancyZonesLib/FancyZonesWindowProperties.h>

namespace FancyZonesUtils
{
    typedef BOOL(WINAPI* GetDpiForMonitorInternalFunc)(HMONITOR, UINT, UINT*, UINT*);

    UINT GetDpiForMonitor(HMONITOR monitor) noexcept
    {
        UINT dpi{};
        if (wil::unique_hmodule user32{ LoadLibrary(L"user32.dll") })
        {
            if (auto func = reinterpret_cast<GetDpiForMonitorInternalFunc>(GetProcAddress(user32.get(), "GetDpiForMonitorInternal")))
            {
                func(monitor, 0, &dpi, &dpi);
            }
        }

        if (dpi == 0)
        {
            if (wil::unique_hdc hdc{ GetDC(nullptr) })
            {
                dpi = GetDeviceCaps(hdc.get(), LOGPIXELSX);
            }
        }

        return (dpi == 0) ? DPIAware::DEFAULT_DPI : dpi;
    }

    void OrderMonitors(std::vector<std::pair<HMONITOR, RECT>>& monitorInfo)
    {
        const size_t nMonitors = monitorInfo.size();
        // blocking[i][j] - whether monitor i blocks monitor j in the ordering, i.e. monitor i should go before monitor j
        std::vector<std::vector<bool>> blocking(nMonitors, std::vector<bool>(nMonitors, false));

        // blockingCount[j] - the number of monitors which block monitor j
        std::vector<size_t> blockingCount(nMonitors, 0);

        for (size_t i = 0; i < nMonitors; i++)
        {
            RECT rectI = monitorInfo[i].second;
            for (size_t j = 0; j < nMonitors; j++)
            {
                RECT rectJ = monitorInfo[j].second;
                blocking[i][j] = rectI.top < rectJ.bottom && rectI.left < rectJ.right && i != j;
                if (blocking[i][j])
                {
                    blockingCount[j]++;
                }
            }
        }

        // used[i] - whether the sorting algorithm has used monitor i so far
        std::vector<bool> used(nMonitors, false);

        // the sorted sequence of monitors
        std::vector<std::pair<HMONITOR, RECT>> sortedMonitorInfo;

        for (size_t iteration = 0; iteration < nMonitors; iteration++)
        {
            // Indices of candidates to become the next monitor in the sequence
            std::vector<size_t> candidates;

            // First, find indices of all unblocked monitors
            for (size_t i = 0; i < nMonitors; i++)
            {
                if (blockingCount[i] == 0 && !used[i])
                {
                    candidates.push_back(i);
                }
            }

            // In the unlikely event that there are no unblocked monitors, declare all unused monitors as candidates.
            if (candidates.empty())
            {
                for (size_t i = 0; i < nMonitors; i++)
                {
                    if (!used[i])
                    {
                        candidates.push_back(i);
                    }
                }
            }

            // Pick the lexicographically smallest monitor as the next one
            size_t smallest = candidates[0];
            for (size_t j = 1; j < candidates.size(); j++)
            {
                size_t current = candidates[j];

                // Compare (top, left) lexicographically
                if (std::tie(monitorInfo[current].second.top, monitorInfo[current].second.left) <
                    std::tie(monitorInfo[smallest].second.top, monitorInfo[smallest].second.left))
                {
                    smallest = current;
                }
            }

            used[smallest] = true;
            sortedMonitorInfo.push_back(monitorInfo[smallest]);
            for (size_t i = 0; i < nMonitors; i++)
            {
                if (blocking[smallest][i])
                {
                    blockingCount[i]--;
                }
            }
        }

        monitorInfo = std::move(sortedMonitorInfo);
    }

    bool IsValidGuid(const std::wstring& str)
    {
        GUID id;
        return SUCCEEDED(CLSIDFromString(str.c_str(), &id));
    }

    std::optional<GUID> GuidFromString(const std::wstring& str) noexcept
    {
        GUID id;
        if (SUCCEEDED(CLSIDFromString(str.c_str(), &id)))
        {
            return id;
        }

        return std::nullopt;
    }

    std::optional<std::wstring> GuidToString(const GUID& guid) noexcept
    {
        wil::unique_cotaskmem_string guidString;
        if (SUCCEEDED(StringFromCLSID(guid, &guidString)))
        {
            return guidString.get();
        }

        return std::nullopt;
    }

    size_t ChooseNextZoneByPosition(DWORD vkCode, RECT windowRect, const std::vector<RECT>& zoneRects) noexcept
    {
        using complex = std::complex<double>;
        const size_t invalidResult = zoneRects.size();
        const double inf = 1e100;
        const double eccentricity = 2.0;

        auto rectCenter = [](RECT rect) {
            return complex{
                0.5 * rect.left + 0.5 * rect.right,
                0.5 * rect.top + 0.5 * rect.bottom
            };
        };

        auto distance = [&](complex arrowDirection, complex zoneDirection) {
            double result = inf;

            try
            {
                double scalarProduct = (arrowDirection * conj(zoneDirection)).real();
                if (scalarProduct <= 0.0)
                {
                    return inf;
                }

                // no need to divide by abs(arrowDirection) because it's = 1
                double cosAngle = scalarProduct / abs(zoneDirection);
                double tanAngle = abs(tan(acos(cosAngle)));

                if (tanAngle > 10)
                {
                    // The angle is too wide
                    return inf;
                }

                // find the intersection with the ellipse with given eccentricity and major axis along arrowDirection
                double intersectY = 2 * eccentricity / (1.0 + eccentricity * eccentricity * tanAngle * tanAngle);
                double distanceEstimate = scalarProduct / intersectY;

                if (std::isfinite(distanceEstimate))
                {
                    result = distanceEstimate;
                }
            }
            catch (...)
            {
            }

            return result;
        };
        std::vector<std::pair<size_t, complex>> candidateCenters;
        for (size_t i = 0; i < zoneRects.size(); i++)
        {
            auto center = rectCenter(zoneRects[i]);

            // Offset the zone slightly, to differentiate in case there are overlapping zones
            center += 0.001 * (i + 1);

            candidateCenters.emplace_back(i, center);
        }

        complex directionVector, windowCenter = rectCenter(windowRect);

        switch (vkCode)
        {
        case VK_UP:
            directionVector = { 0.0, -1.0 };
            break;
        case VK_DOWN:
            directionVector = { 0.0, 1.0 };
            break;
        case VK_LEFT:
            directionVector = { -1.0, 0.0 };
            break;
        case VK_RIGHT:
            directionVector = { 1.0, 0.0 };
            break;
        default:
            return invalidResult;
        }

        size_t closestIdx = invalidResult;
        double smallestDistance = inf;

        for (auto [zoneIdx, zoneCenter] : candidateCenters)
        {
            double dist = distance(directionVector, zoneCenter - windowCenter);
            if (dist < smallestDistance)
            {
                smallestDistance = dist;
                closestIdx = zoneIdx;
            }
        }

        return closestIdx;
    }

    void SwallowKey(const WORD key) noexcept
    {
        INPUT inputKey[1] = {};
        inputKey[0].type = INPUT_KEYBOARD;
        inputKey[0].ki.wVk = key;
        inputKey[0].ki.dwFlags = KEYEVENTF_KEYUP;
        SendInput(1, inputKey, sizeof(INPUT));
    }
}