#include <gtest/gtest.h>

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkConeSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>

#include "CameraPreset.hpp"

using namespace geopro::render;

namespace {

// 造一个带包围盒的 renderer（一个 cone actor），使 ResetCamera 有内容可重定位。
vtkSmartPointer<vtkRenderer> rendererWithContent() {
    auto cone = vtkSmartPointer<vtkConeSource>::New();
    cone->SetCenter(0, 0, 0);
    cone->SetHeight(2.0);
    cone->SetRadius(1.0);
    auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(cone->GetOutputPort());
    auto actor = vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);
    auto r = vtkSmartPointer<vtkRenderer>::New();
    r->AddActor(actor);
    return r;
}

// 相机的视线方向单位向量 = focalPoint - position（归一化）。
void viewDir(vtkRenderer* r, double out[3]) {
    auto* c = r->GetActiveCamera();
    double p[3], f[3];
    c->GetPosition(p);
    c->GetFocalPoint(f);
    double d[3] = {f[0] - p[0], f[1] - p[1], f[2] - p[2]};
    double n = std::sqrt(d[0] * d[0] + d[1] * d[1] + d[2] * d[2]);
    out[0] = d[0] / n; out[1] = d[1] / n; out[2] = d[2] / n;
}

}  // namespace

// Top：相机在焦点上方(pos.z>focal.z)，视线朝 -Z，viewUp=+Y。
TEST(CameraPreset, TopLooksDown) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Top);
    auto* c = r->GetActiveCamera();
    double p[3], f[3], up[3];
    c->GetPosition(p); c->GetFocalPoint(f); c->GetViewUp(up);
    EXPECT_GT(p[2], f[2]);  // 相机在上方
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[2], -1.0, 1e-6);  // 视线向下
    EXPECT_NEAR(up[1], 1.0, 1e-6);  // 北朝上
}

// Bottom：相机在焦点下方，视线朝 +Z。
TEST(CameraPreset, BottomLooksUp) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Bottom);
    auto* c = r->GetActiveCamera();
    double p[3], f[3];
    c->GetPosition(p); c->GetFocalPoint(f);
    EXPECT_LT(p[2], f[2]);
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[2], 1.0, 1e-6);
}

// Front：相机在 -Y，视线朝 +Y，viewUp=+Z。
TEST(CameraPreset, FrontLooksNorth) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Front);
    auto* c = r->GetActiveCamera();
    double p[3], f[3], up[3];
    c->GetPosition(p); c->GetFocalPoint(f); c->GetViewUp(up);
    EXPECT_LT(p[1], f[1]);
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[1], 1.0, 1e-6);
    EXPECT_NEAR(up[2], 1.0, 1e-6);
}

// Back：相机在 +Y，视线朝 -Y。
TEST(CameraPreset, BackLooksSouth) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Back);
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[1], -1.0, 1e-6);
}

// Left：相机在 -X，视线朝 +X。
TEST(CameraPreset, LeftLooksEast) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Left);
    auto* c = r->GetActiveCamera();
    double p[3], f[3];
    c->GetPosition(p); c->GetFocalPoint(f);
    EXPECT_LT(p[0], f[0]);
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[0], 1.0, 1e-6);
}

// Right：相机在 +X，视线朝 -X。
TEST(CameraPreset, RightLooksWest) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Right);
    double d[3]; viewDir(r, d);
    EXPECT_NEAR(d[0], -1.0, 1e-6);
}

// zoomBy(>1) 放大：透视下 vtkCamera::Zoom 收窄视角（ViewAngle 变小→画面放大）。
TEST(CameraPreset, ZoomInNarrowsViewAngle) {
    auto r = rendererWithContent();
    applyFree3D(r);
    auto* c = r->GetActiveCamera();
    const double before = c->GetViewAngle();
    zoomBy(r, 1.2);
    EXPECT_LT(c->GetViewAngle(), before);
}

// zoomBy(<1) 缩小：透视下视角变宽（画面缩小）。
TEST(CameraPreset, ZoomOutWidensViewAngle) {
    auto r = rendererWithContent();
    applyFree3D(r);
    auto* c = r->GetActiveCamera();
    const double before = c->GetViewAngle();
    zoomBy(r, 1.0 / 1.2);
    EXPECT_GT(c->GetViewAngle(), before);
}

// 正交投影下 zoomBy 改 parallelScale（放大缩小可视范围）。
TEST(CameraPreset, ZoomInOrthoReducesParallelScale) {
    auto r = rendererWithContent();
    applyView(r, ViewDir::Top);  // Top 不改投影模式；显式打开正交
    auto* c = r->GetActiveCamera();
    c->ParallelProjectionOn();
    r->ResetCamera();
    const double before = c->GetParallelScale();
    zoomBy(r, 2.0);
    EXPECT_LT(c->GetParallelScale(), before);
}

// 空指针/非法 factor 安全。
TEST(CameraPreset, NullAndInvalidAreSafe) {
    applyView(nullptr, ViewDir::Top);
    zoomBy(nullptr, 1.2);
    fitView(nullptr);
    auto r = rendererWithContent();
    const double before = r->GetActiveCamera()->GetDistance();
    zoomBy(r, 0.0);  // 非法 factor 忽略
    zoomBy(r, -1.0);
    EXPECT_DOUBLE_EQ(r->GetActiveCamera()->GetDistance(), before);
}