#include "interact/PickInteractorStyle.hpp"

#include <chrono>

#include <vtkCamera.h>
#include <vtkCellPicker.h>
#include <vtkMath.h>
#include <vtkNew.h>
#include <vtkObjectFactory.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkTransform.h>

namespace geopro::render::interact {

namespace {
constexpr double kDoubleClickMs = 350.0;  // 两次左键按下间隔阈值
constexpr int kClickSlopPx2 = 36;         // 位置相近阈值平方(6px)

// 当前单调时钟(毫秒)。用 std::chrono 避免依赖 VTK::CommonSystem(vtkTimerLog)。
double nowMs() {
    return std::chrono::duration<double, std::milli>(
               std::chrono::steady_clock::now().time_since_epoch())
        .count();
}
}  // namespace

vtkStandardNewMacro(PickInteractorStyle);

bool PickInteractorStyle::pickWorld(Vec3& out) {
    auto* iren = this->GetInteractor();
    if (!iren) return false;
    const int* pos = iren->GetEventPosition();
    // 用交互器解析被点中的 renderer（基类 FindPokedRenderer 仅设 CurrentRenderer、返回 void）。
    auto* ren = iren->FindPokedRenderer(pos[0], pos[1]);
    if (!ren) return false;
    // CellPicker：返回表面交点世界坐标（命中切片纹理面/帘面等）。
    vtkNew<vtkCellPicker> picker;
    picker->SetTolerance(0.005);
    if (!picker->Pick(pos[0], pos[1], 0.0, ren)) return false;
    double w[3];
    picker->GetPickPosition(w);
    out = {w[0], w[1], w[2]};
    return true;
}

void PickInteractorStyle::OnLeftButtonDown() {
    auto* iren = this->GetInteractor();
    Vec3 world;
    const bool hit = pickWorld(world);

    // 手动双击判定（GetRepeatCount 在 QVTK+Windows 不可靠，评审 M5）：
    //   两次左键按下间隔 < 阈值且屏幕位置相近 → 双击。
    const double now = nowMs();
    const int* pos = iren ? iren->GetEventPosition() : nullptr;
    bool isDouble = false;
    if (hit && pos && lastDownTime_ >= 0.0) {
        const double dtMs = now - lastDownTime_;
        const int dx = pos[0] - lastDownPos_[0];
        const int dy = pos[1] - lastDownPos_[1];
        if (dtMs < kDoubleClickMs && (dx * dx + dy * dy) <= kClickSlopPx2) isDouble = true;
    }
    if (pos) {
        lastDownPos_[0] = pos[0];
        lastDownPos_[1] = pos[1];
    }
    lastDownTime_ = now;

    if (isDouble) {
        // 双击命中 → 正视所在切片（manager 找最近切片 + 算相机）。
        if (onDoubleClick) onDoubleClick(world);
        lastDownTime_ = -1.0;  // 重置，避免三击连判
        return;                // 不进入拖动旋转
    }
    if (hit) {
        // 单击命中 → 选中所在切片（onPick 内仅选中, 不动相机）。
        if (onPick) onPick(world);
    }
    // 不在按下时动相机（动相机=跳）；绕选中物旋转在 Rotate() 内做（增量绕支点，不跳）。
    Superclass::OnLeftButtonDown();
}

void PickInteractorStyle::Rotate() {
    Vec3 c;
    if (!this->CurrentRenderer || !getRotateCenter || !getRotateCenter(c)) {
        Superclass::Rotate();  // 无选中物 → 默认绕焦点旋转
        return;
    }
    auto* rwi = this->Interactor;
    auto* cam = this->CurrentRenderer->GetActiveCamera();
    if (!rwi || !cam) return;
    const int dx = rwi->GetEventPosition()[0] - rwi->GetLastEventPosition()[0];
    const int dy = rwi->GetEventPosition()[1] - rwi->GetLastEventPosition()[1];
    const int* size = this->CurrentRenderer->GetRenderWindow()->GetSize();
    if (size[0] <= 0 || size[1] <= 0) return;
    // 与 TrackballCamera 同口径的角度映射。
    const double azimuth = dx * (-20.0 / size[0]) * this->MotionFactor;
    const double elevation = dy * (-20.0 / size[1]) * this->MotionFactor;

    double up[3], dop[3], right[3];
    cam->GetViewUp(up);
    cam->GetDirectionOfProjection(dop);  // 归一化的 (focal-pos)
    vtkMath::Cross(dop, up, right);       // 屏幕"右"轴
    vtkMath::Normalize(right);

    // 绕中心 c 的支点：T(c)·R(up,azimuth)·R(right,elevation)·T(-c)，作用于 position/focal；up 只转不平移。
    vtkNew<vtkTransform> t;
    t->Identity();
    t->Translate(c[0], c[1], c[2]);
    t->RotateWXYZ(azimuth, up[0], up[1], up[2]);
    t->RotateWXYZ(elevation, right[0], right[1], right[2]);
    t->Translate(-c[0], -c[1], -c[2]);

    double pos[3], foc[3], npos[3], nfoc[3], nup[3];
    cam->GetPosition(pos);
    cam->GetFocalPoint(foc);
    t->TransformPoint(pos, npos);
    t->TransformPoint(foc, nfoc);
    t->TransformVector(up, nup);  // 仅旋转部分作用于向量
    cam->SetPosition(npos);
    cam->SetFocalPoint(nfoc);
    cam->SetViewUp(nup);
    cam->OrthogonalizeViewUp();
    if (this->AutoAdjustCameraClippingRange) this->CurrentRenderer->ResetCameraClippingRange();
    rwi->Render();
}

void PickInteractorStyle::OnMouseWheelForward() {
    if (onWheelStep && onWheelStep(+1)) return;  // 有选中切片 → 推进，消费滚轮
    Superclass::OnMouseWheelForward();           // 否则默认缩放
}

void PickInteractorStyle::OnMouseWheelBackward() {
    if (onWheelStep && onWheelStep(-1)) return;
    Superclass::OnMouseWheelBackward();
}

}  // namespace geopro::render::interact