#include "Viewporter.hpp"
#include "core/Compositor.hpp"
#include <algorithm>
#include <cmath>

CViewportResource::CViewportResource(SP<CWpViewport> resource_, SP<CWLSurfaceResource> surface_) : m_surface(surface_), m_resource(resource_) {
    if UNLIKELY (!good())
        return;

    m_resource->setDestroy([this](CWpViewport* r) { PROTO::viewport->destroyResource(this); });
    m_resource->setOnDestroy([this](CWpViewport* r) { PROTO::viewport->destroyResource(this); });

    m_resource->setSetDestination([this](CWpViewport* r, int32_t x, int32_t y) {
        if UNLIKELY (!m_surface) {
            r->error(WP_VIEWPORT_ERROR_NO_SURFACE, "Surface is gone");
            return;
        }

        m_surface->m_pending.updated.bits.viewport = true;

        if (x == -1 && y == -1) {
            m_surface->m_pending.viewport.hasDestination = false;
            return;
        }

        if UNLIKELY (x <= 0 || y <= 0) {
            r->error(WP_VIEWPORT_ERROR_BAD_SIZE, "Size was <= 0");
            return;
        }

        m_surface->m_pending.viewport.hasDestination = true;
        m_surface->m_pending.viewport.destination    = {x, y};
    });

    m_resource->setSetSource([this](CWpViewport* r, wl_fixed_t fx, wl_fixed_t fy, wl_fixed_t fw, wl_fixed_t fh) {
        if UNLIKELY (!m_surface) {
            r->error(WP_VIEWPORT_ERROR_NO_SURFACE, "Surface is gone");
            return;
        }

        m_surface->m_pending.updated.bits.viewport = true;

        double x = wl_fixed_to_double(fx), y = wl_fixed_to_double(fy), w = wl_fixed_to_double(fw), h = wl_fixed_to_double(fh);

        if (x == -1 && y == -1 && w == -1 && h == -1) {
            m_surface->m_pending.viewport.hasSource = false;
            return;
        }

        if UNLIKELY (x < 0 || y < 0) {
            r->error(WP_VIEWPORT_ERROR_BAD_SIZE, "Pos was < 0");
            return;
        }

        m_surface->m_pending.viewport.hasSource = true;
        m_surface->m_pending.viewport.source    = {x, y, w, h};
    });

    m_listeners.surfacePrecommit = m_surface->m_events.precommit.listen([this] {
        if (!m_surface || !m_surface->m_pending.buffer)
            return;

        if (m_surface->m_pending.viewport.hasSource) {
            auto&       src  = m_surface->m_pending.viewport.source;
            const auto& size = m_surface->m_pending.bufferSize;

            if (size.x <= 0.0 || size.y <= 0.0)
                return;

            constexpr wl_fixed_t MAX_TOLERANCE = 1 << 8; // wl_fixed 1.0 = 256

            auto                 clampAxis = [&](double& start, double& length, double limit) -> bool {
                const double     originalStart = start;
                const double     originalEnd   = start + length;
                const double     clampedStart  = std::clamp(start, 0.0, std::max(0.0, limit));
                const double     clampedEnd    = std::clamp(originalEnd, 0.0, std::max(0.0, limit));
                const wl_fixed_t startDelta    = std::abs(wl_fixed_from_double(clampedStart) - wl_fixed_from_double(originalStart));
                const wl_fixed_t endDelta      = std::abs(wl_fixed_from_double(clampedEnd) - wl_fixed_from_double(originalEnd));

                if (startDelta > MAX_TOLERANCE || endDelta > MAX_TOLERANCE)
                    return false;

                start  = clampedStart;
                length = clampedEnd - clampedStart;
                return length > 0.0;
            };

            // Viewporter spec order: 1. transform, 2. scale, 3. viewport
            Vector2D sizeScaledTransformed = (m_surface->m_pending.transform % 2 == 1 ? Vector2D{size.y, size.x} : size) / m_surface->m_pending.scale;
            if (!clampAxis(src.x, src.w, sizeScaledTransformed.x) || !clampAxis(src.y, src.h, sizeScaledTransformed.y)) {
                m_resource->error(WP_VIEWPORT_ERROR_BAD_VALUE, "Box doesn't fit");
                m_surface->m_pending.rejected = true;
                return;
            }
        }
    });
}

CViewportResource::~CViewportResource() {
    if (!m_surface)
        return;

    m_surface->m_pending.viewport.hasDestination = false;
    m_surface->m_pending.viewport.hasSource      = false;
}

bool CViewportResource::good() {
    return m_resource->resource();
}

CViewporterResource::CViewporterResource(SP<CWpViewporter> resource_) : m_resource(resource_) {
    if UNLIKELY (!good())
        return;

    m_resource->setDestroy([this](CWpViewporter* r) { PROTO::viewport->destroyResource(this); });
    m_resource->setOnDestroy([this](CWpViewporter* r) { PROTO::viewport->destroyResource(this); });

    m_resource->setGetViewport([](CWpViewporter* r, uint32_t id, wl_resource* surf) {
        const auto RESOURCE = PROTO::viewport->m_viewports.emplace_back(
            makeShared<CViewportResource>(makeShared<CWpViewport>(r->client(), r->version(), id), CWLSurfaceResource::fromResource(surf)));

        if UNLIKELY (!RESOURCE->good()) {
            r->noMemory();
            PROTO::viewport->m_viewports.pop_back();
            return;
        }
    });
}

bool CViewporterResource::good() {
    return m_resource->resource();
}

CViewporterProtocol::CViewporterProtocol(const wl_interface* iface, const int& ver, const std::string& name) : IWaylandProtocol(iface, ver, name) {
    ;
}

void CViewporterProtocol::bindManager(wl_client* client, void* data, uint32_t ver, uint32_t id) {
    const auto RESOURCE = m_managers.emplace_back(makeShared<CViewporterResource>(makeShared<CWpViewporter>(client, ver, id)));

    if UNLIKELY (!RESOURCE->good()) {
        wl_client_post_no_memory(client);
        m_managers.pop_back();
        return;
    }
}

void CViewporterProtocol::destroyResource(CViewporterResource* resource) {
    std::erase_if(m_managers, [&](const auto& other) { return other.get() == resource; });
}

void CViewporterProtocol::destroyResource(CViewportResource* resource) {
    std::erase_if(m_viewports, [&](const auto& other) { return other.get() == resource; });
}
