#pragma once
/**
 * @file parallel_intersection.h
 * @brief 并行曲面/曲线求交
 *
 * OpenMP 并行化曲面-曲面求交和曲线-曲线求交。
 *
 * @ingroup curves
 */

#include "vde/core/point.h"
#include "vde/curves/nurbs_curve.h"
#include "vde/curves/nurbs_surface.h"
#include <vector>
#include <utility>

namespace vde::curves {

// ═══════════════════════════════════════════════════════════
//  Parallel Curve Intersection
// ═══════════════════════════════════════════════════════════

/**
 * @brief 并行计算一组曲线对的交点
 *
 * 每对曲线独立求交，结果线程安全合并。
 *
 * @param curve_pairs 曲线对列表 ((curve_a_idx, curve_b_idx), ...)
 * @param curves_a 曲线集合 A
 * @param curves_b 曲线集合 B
 * @return 每条曲线对的交点参数列表
 */
[[nodiscard]] std::vector<std::vector<std::pair<double, double>>>
parallel_curve_intersections(
    const std::vector<std::pair<int, int>>& curve_pairs,
    const std::vector<NurbsCurve>& curves_a,
    const std::vector<NurbsCurve>& curves_b);

// ═══════════════════════════════════════════════════════════
//  Parallel Surface Intersection
// ═══════════════════════════════════════════════════════════

/// 曲面交线段
struct SurfaceIntersectionSegment {
    core::Point3D start;
    core::Point3D end;
    double u_a_start, v_a_start;
    double u_a_end, v_a_end;
    double u_b_start, v_b_start;
    double u_b_end, v_b_end;
};

/**
 * @brief 并行计算两曲面的交线
 *
 * 递归细分 + 牛顿精化，边界盒预筛选，并行分发。
 *
 * @param surf_a 曲面 A
 * @param surf_b 曲面 B
 * @param tolerance 精度要求
 * @param max_refinements 最大细分次数
 * @return 交线段列表
 */
[[nodiscard]] std::vector<SurfaceIntersectionSegment>
parallel_surface_intersection(
    const NurbsSurface& surf_a, const NurbsSurface& surf_b,
    double tolerance = 1e-6, int max_refinements = 10);

/**
 * @brief 并行批量曲面-曲面对求交
 *
 * @param pairs 曲面对索引
 * @param surfaces_a 曲面集合 A
 * @param surfaces_b 曲面集合 B
 * @return 每对曲面的交线段列表
 */
[[nodiscard]] std::vector<std::vector<SurfaceIntersectionSegment>>
parallel_surface_intersections(
    const std::vector<std::pair<int, int>>& pairs,
    const std::vector<NurbsSurface>& surfaces_a,
    const std::vector<NurbsSurface>& surfaces_b,
    double tolerance = 1e-6);

} // namespace vde::curves