#pragma once

#include "SplineCurveModel.h"
#include "ItemCurve.h"
#include <vector>

class CSigmaDoc;  // forward declaration for GetDoc()

/**
 * @brief 样条拖拽状态
 *
 * 集中管理鼠标按下/拖拽位置及预览点，与 CurveEditorSpline 共享。
 */
struct SplineDragState
{
	CPoint screenDownPoint;
	CPoint2D worldDownPoint;
	CPoint2D worldLastPoint;
	bool isLeftButtonDownDuringMove;
	CPointList previewPoints;

	void Reset()
	{
		worldDownPoint = CPoint2D(0, 0);
		worldLastPoint = CPoint2D(0, 0);
		isLeftButtonDownDuringMove = false;
		previewPoints.RemoveAll();
	}
	void StartDrag(CPoint screen, CPoint2D world)
	{
		screenDownPoint = screen;
		worldDownPoint = world;
		worldLastPoint = world;
		previewPoints.RemoveAll();
	}
	void UpdateLast(CPoint2D world) { worldLastPoint = world; }
	bool HasMoved() const { return !(worldLastPoint == worldDownPoint); }
};

/**
 * @brief 拖拽流水线上下文接口
 *
 * CurveEditorSpline 实现，供 SplineDragPipeline 访问文档与模型。
 */
struct ISplineDragPipelineContext
{
	virtual ~ISplineDragPipelineContext() = default;
	virtual CSigmaDoc* GetDoc() = 0;
	virtual POSITION GetPos() = 0;
	virtual int GetHandleIndex() = 0;
	virtual void WriteModelToDocCurve() = 0;
	virtual void Invalidate() = 0;
	virtual void AttachProcess(CPointList& oldPoints, CPointList& newPoints) = 0;
};

/**
 * @brief 样条拖拽流水线
 *
 * 根据拖拽状态计算并应用/预览效果，流程：取曲线 → 重建样条 → 写回 → 同步模型。
 */
class SplineDragPipeline
{
public:
	SplineDragPipeline(SplineCurveModel& model, SplineDragState& dragState, ISplineDragPipelineContext* pContext);

	/**
	 * @brief 执行拖拽步骤，isPreview 为 true 时仅输出预览点到 pListForPreview
	 */
	bool ProcessDragStep(bool isPreview, CPointList* pListForPreview);

private:
	bool GetCurveForDragEdit(bool isPreview, CCurveEx*& pValue, int& handleIndex, CPointList* pListForPreview);
	bool GetDraggedSegmentAndAttachContext(std::vector<dfPoint>& segmentVec);
	bool WriteDraggedSegmentToCurve(CCurveEx* pValue, const std::vector<dfPoint>& segmentVec);
	void SyncControlPointsAndNotify(int handleIndex);
	void EndDragEdit(CCurveEx* pValue, bool isPreview, CPointList* pList);

	SplineCurveModel* m_pModel;
	SplineDragState* m_pDragState;
	ISplineDragPipelineContext* m_pContext;
};