package lujing;
import java.util.*;


/**
 * 异形草地路径规划 - 含障碍物版
 * 功能：在地块内部避开障碍物，生成连续弓字形割草路径
 */
public class YixinglujingHaveObstacel {
    
    public static List<PathSegment> planPath(String coordinates, String obstaclesStr, 
                                            String widthStr, String marginStr) {
        // 1. 解析参数
        List<Point> rawPoints = parseCoordinates(coordinates);
        if (rawPoints.size() < 3) return new ArrayList<>();
        
        double mowWidth = Double.parseDouble(widthStr);
        double safeMargin = Double.parseDouble(marginStr);
        
        // 解析障碍物
        List<Obstacle> obstacles = parseObstacles(obstaclesStr);
        
        // 2. 预处理：确保边界逆时针
        ensureCounterClockwise(rawPoints);
        
        // 3. 生成内缩多边形（安全边界）
        List<Point> boundary = getInsetPolygon(rawPoints, safeMargin);
        if (boundary.size() < 3) return new ArrayList<>();
        
        // 4. 外扩障碍物（安全边距）
        List<Obstacle> expandedObstacles = expandObstacles(obstacles, safeMargin);
        
        // 5. 确定最优作业角度
        double bestAngle = findOptimalAngle(boundary);
        
        // 6. 获取首个作业点，用于对齐围边起点
        Point firstScanStart = getFirstScanPoint(boundary, mowWidth, bestAngle);
        
        // 7. 对齐围边
        List<Point> alignedBoundary = alignBoundaryStart(boundary, firstScanStart);
        
        // 8. 第一阶段：围边路径
        List<PathSegment> finalPath = new ArrayList<>();
        for (int i = 0; i < alignedBoundary.size(); i++) {
            Point pStart = alignedBoundary.get(i);
            Point pEnd = alignedBoundary.get((i + 1) % alignedBoundary.size());
            finalPath.add(new PathSegment(pStart, pEnd, true));
        }
        
        // 9. 第二阶段：生成内部扫描路径（考虑障碍物）
        Point lastEdgePos = alignedBoundary.get(0);
        List<PathSegment> scanPath = generateGlobalScanPathWithObstacles(
            boundary, expandedObstacles, mowWidth, bestAngle, lastEdgePos);
        
        finalPath.addAll(scanPath);
        
        // 10. 格式化坐标：保留两位小数
        for (PathSegment segment : finalPath) {
            segment.start.x = Math.round(segment.start.x * 100.0) / 100.0;
            segment.start.y = Math.round(segment.start.y * 100.0) / 100.0;
            segment.end.x = Math.round(segment.end.x * 100.0) / 100.0;
            segment.end.y = Math.round(segment.end.y * 100.0) / 100.0;
        }
        
        // 11. 打印输出路径坐标
        printPathCoordinates(finalPath);
        
        return finalPath;
    }
    
    /**
     * 生成带障碍物的扫描路径
     */
    private static List<PathSegment> generateGlobalScanPathWithObstacles(
            List<Point> polygon, List<Obstacle> obstacles, 
            double width, double angle, Point startPos) {
        
        // 1. 生成原始扫描线（无障碍物）
        List<PathSegment> originalSegments = generateGlobalScanPath(polygon, width, angle, startPos);
        
        // 2. 移除在障碍物内部的线段
        List<PathSegment> remainingSegments = new ArrayList<>();
        for (PathSegment seg : originalSegments) {
            if (!seg.isMowing) {
                // 空走段直接保留
                remainingSegments.add(seg);
                continue;
            }
            
            // 将割草段与所有障碍物进行裁剪
            List<PathSegment> clippedSegments = new ArrayList<>();
            clippedSegments.add(seg);
            
            for (Obstacle obs : obstacles) {
                List<PathSegment> newSegments = new ArrayList<>();
                for (PathSegment s : clippedSegments) {
                    newSegments.addAll(clipSegmentWithObstacle(s, obs));
                }
                clippedSegments = newSegments;
            }
            
            remainingSegments.addAll(clippedSegments);
        }
        
        // 3. 重新连接路径段（弓字形连接，智能处理边界穿越）
        return reconnectSegments(remainingSegments, polygon);
    }
    
    /**
     * 将线段与障碍物进行裁剪
     * 返回不在障碍物内部的子线段
     */
    private static List<PathSegment> clipSegmentWithObstacle(PathSegment segment, Obstacle obstacle) {
        List<PathSegment> result = new ArrayList<>();
        
        // 检查线段是否完全在障碍物外部
        boolean startInside = obstacle.contains(segment.start);
        boolean endInside = obstacle.contains(segment.end);
        
        if (!startInside && !endInside) {
            // 线段两端都在外部，检查是否穿过障碍物
            List<Point> intersections = obstacle.getIntersections(segment);
            if (intersections.isEmpty()) {
                // 完全在外部
                result.add(segment);
            } else {
                // 穿过障碍物，分割线段
                intersections.sort(Comparator.comparingDouble(p -> 
                    distance(segment.start, p)));
                
                Point prevPoint = segment.start;
                for (Point inter : intersections) {
                    result.add(new PathSegment(prevPoint, inter, true));
                    prevPoint = inter;
                }
                result.add(new PathSegment(prevPoint, segment.end, true));
                
                // 移除在障碍物内部的段（奇数索引的段）
                List<PathSegment> filtered = new ArrayList<>();
                for (int i = 0; i < result.size(); i++) {
                    PathSegment s = result.get(i);
                    Point midPoint = new Point(
                        (s.start.x + s.end.x) / 2,
                        (s.start.y + s.end.y) / 2
                    );
                    if (!obstacle.contains(midPoint)) {
                        filtered.add(s);
                    }
                }
                return filtered;
            }
        } else if (startInside && endInside) {
            // 完全在内部，丢弃
            return result;
        } else {
            // 一端在内部，一端在外部
            Point outsidePoint = startInside ? segment.end : segment.start;
            
            List<Point> intersections = obstacle.getIntersections(segment);
            if (!intersections.isEmpty()) {
                // 取离外部点最近的交点
                intersections.sort(Comparator.comparingDouble(p -> 
                    distance(outsidePoint, p)));
                Point inter = intersections.get(0);
                
                // 只保留外部部分
                if (startInside) {
                    result.add(new PathSegment(inter, outsidePoint, true));
                } else {
                    result.add(new PathSegment(outsidePoint, inter, true));
                }
            }
        }
        
        return result;
    }
    
    /**
     * 重新连接路径段，形成连续弓字形路径
     * 优化：智能处理边界穿越，当换行路径穿越边界时，沿边界行走
     */
    private static List<PathSegment> reconnectSegments(List<PathSegment> segments, List<Point> boundary) {
        if (segments.isEmpty()) return new ArrayList<>();
        
        List<PathSegment> reconnected = new ArrayList<>();
        Point currentPos = segments.get(0).start;
        
        for (PathSegment seg : segments) {
            if (seg.isMowing) {
                // 割草段：检查是否需要添加空走段
                if (distance(currentPos, seg.start) > 0.01) {
                    // 使用智能连接方法生成换行路径
                    List<PathSegment> connectionPath = buildSmartConnection(currentPos, seg.start, boundary);
                    reconnected.addAll(connectionPath);
                }
                reconnected.add(seg);
                currentPos = seg.end;
            } else {
                // 空走段直接添加
                reconnected.add(seg);
                currentPos = seg.end;
            }
        }
        
        return reconnected;
    }
    
    /**
     * 智能连接两点：如果直线不穿越边界则直接连接，否则使用直线+边界混合路径
     * 优化逻辑：
     * 1. 如果AB线不穿越边界C，直接使用AB作为换行路线
     * 2. 如果AB线穿越了边界C，找到所有交点，将AB分成多个段
     *    - 对于在边界内部的段（如DF段、GH段），沿边界行走
     *    - 对于在边界外部的段，沿AB直线行走
     *    路径示例：A → D(直线) → F(沿边界) → G(直线) → H(沿边界) → B(直线)
     * 
     * @param pointA 起点（上一段结束的终点）
     * @param pointB 终点（下一段需要割草路径的起始点）
     * @param boundary 安全内缩边界C
     * @return 连接路径段列表（全部为isMowing=false的空走段）
     */
    private static List<PathSegment> buildSmartConnection(Point pointA, Point pointB, List<Point> boundary) {
        List<PathSegment> result = new ArrayList<>();
        
        // 1. 检查AB直线是否穿越边界C
        if (!segmentIntersectsBoundary(pointA, pointB, boundary)) {
            // 不穿越边界，直接使用AB作为换行路线
            result.add(new PathSegment(pointA, pointB, false));
            return result;
        }
        
        // 2. AB线穿越了边界C，需要找到所有交点
        List<IntersectionInfo> intersections = getAllBoundaryIntersections(pointA, pointB, boundary);
        
        if (intersections.isEmpty()) {
            // 没有交点（不应该发生，但安全处理），使用直线
            result.add(new PathSegment(pointA, pointB, false));
            return result;
        }
        
        // 3. 按距离起点A的距离排序交点
        intersections.sort(Comparator.comparingDouble(inter -> distance(pointA, inter.point)));
        
        // 4. 构建完整的点序列：A, I1, I2, ..., In, B（I为交点）
        List<Point> pointSequence = new ArrayList<>();
        pointSequence.add(pointA);
        for (IntersectionInfo inter : intersections) {
            pointSequence.add(inter.point);
        }
        pointSequence.add(pointB);
        
        // 5. 处理每两个相邻点之间的段
        Point currentPos = pointA;
        
        for (int i = 0; i < pointSequence.size() - 1; i++) {
            Point p1 = pointSequence.get(i);
            Point p2 = pointSequence.get(i + 1);
            
            // 判断p1到p2的段（AB线段的一部分）是否在边界C内部（检查中点）
            Point midPoint = new Point((p1.x + p2.x) / 2, (p1.y + p2.y) / 2);
            boolean segmentInsideBoundary = isPointInPolygon(midPoint, boundary);
            
            if (segmentInsideBoundary) {
                // 段在边界内部（如DF段、GH段），需要沿边界行走
                if (i == 0) {
                    // 第一个段：从A到第一个交点D
                    // 如果段在边界内部，说明A在边界内部，需要先从A沿边界走到第一个交点
                    IntersectionInfo firstInter = intersections.get(0);
                    SnapResult snapA = snapToBoundary(currentPos, boundary);
                    List<PathSegment> boundaryPath = getBoundaryPathBetweenPoints(
                        snapA.onEdge, snapA.edgeIndex,
                        firstInter.point, firstInter.edgeIndex,
                        boundary);
                    result.addAll(boundaryPath);
                    currentPos = firstInter.point;
                } else if (i == pointSequence.size() - 2) {
                    // 最后一个段：从最后一个交点H到B
                    // 需要沿边界从当前点（应该是最后一个交点H）到B在边界上的投影
                    IntersectionInfo lastInter = intersections.get(intersections.size() - 1);
                    SnapResult snapB = snapToBoundary(pointB, boundary);
                    List<PathSegment> boundaryPath = getBoundaryPathBetweenPoints(
                        currentPos, lastInter.edgeIndex,
                        snapB.onEdge, snapB.edgeIndex,
                        boundary);
                    result.addAll(boundaryPath);
                    // 如果B不在边界上，从边界投影直线到B
                    if (distance(snapB.onEdge, pointB) > 1e-6) {
                        result.add(new PathSegment(snapB.onEdge, pointB, false));
                    }
                    currentPos = pointB;
                } else {
                    // 中间段：两个交点之间的段（都在边界上），沿边界行走
                    IntersectionInfo inter1 = intersections.get(i - 1);
                    IntersectionInfo inter2 = intersections.get(i);
                    List<PathSegment> boundaryPath = getBoundaryPathBetweenPoints(
                        inter1.point, inter1.edgeIndex,
                        inter2.point, inter2.edgeIndex,
                        boundary);
                    result.addAll(boundaryPath);
                    currentPos = inter2.point;
                }
            } else {
                // 段在边界外部，可以直接沿AB直线连接（如A到D，F到G，H到B）
                if (distance(p1, p2) > 1e-6) {
                    // 如果当前点不在p1，先连接到p1
                    if (distance(currentPos, p1) > 1e-6) {
                        result.add(new PathSegment(currentPos, p1, false));
                    }
                    // 从p1直线到p2
                        result.add(new PathSegment(p1, p2, false));
                    currentPos = p2;
                }
            }
        }
        
        return result;
    }
    
    /**
     * 检查线段是否穿越边界（与边界边相交，不包括端点）
     */
    private static boolean segmentIntersectsBoundary(Point a, Point b, List<Point> boundary) {
        for (int i = 0; i < boundary.size(); i++) {
            Point c = boundary.get(i);
            Point d = boundary.get((i + 1) % boundary.size());
            // 忽略共享端点的相交
            if (isSamePoint(a, c) || isSamePoint(a, d) || isSamePoint(b, c) || isSamePoint(b, d)) {
                continue;
            }
            if (segmentsIntersect(a, b, c, d)) {
                return true;
            }
        }
        return false;
    }
    
    /**
     * 获取线段与边界的所有交点信息（包括点和对应边索引）
     */
    private static List<IntersectionInfo> getAllBoundaryIntersections(Point a, Point b, List<Point> boundary) {
        List<IntersectionInfo> intersections = new ArrayList<>();
        
        for (int i = 0; i < boundary.size(); i++) {
            Point c = boundary.get(i);
            Point d = boundary.get((i + 1) % boundary.size());
            
            // 忽略共享端点
            if (isSamePoint(a, c) || isSamePoint(a, d) || isSamePoint(b, c) || isSamePoint(b, d)) {
                continue;
            }
            
            Point intersection = getLineIntersection(a, b, c, d);
            if (intersection != null) {
                intersections.add(new IntersectionInfo(intersection, i));
            }
        }
        
        return intersections;
    }
    
    /**
     * 获取边界上两点之间的路径（沿边界行走）
     * @param start 起点（必须在边界上）
     * @param startEdgeIndex 起点所在的边索引
     * @param end 终点（必须在边界上）
     * @param endEdgeIndex 终点所在的边索引
     * @param boundary 边界点列表
     * @return 沿边界的路径段列表
     */
    private static List<PathSegment> getBoundaryPathBetweenPoints(
            Point start, int startEdgeIndex, 
            Point end, int endEdgeIndex, 
            List<Point> boundary) {
        
        List<PathSegment> result = new ArrayList<>();
        
        if (startEdgeIndex == endEdgeIndex) {
            // 在同一条边上，直接连接
            if (distance(start, end) > 1e-6) {
                result.add(new PathSegment(start, end, false));
            }
            return result;
        }
        
        int n = boundary.size();
        
        // 计算顺时针路径
        List<Point> pathClockwise = new ArrayList<>();
        pathClockwise.add(start);
        
        int curr = startEdgeIndex;
        while (curr != endEdgeIndex) {
            pathClockwise.add(boundary.get((curr + 1) % n));
            curr = (curr + 1) % n;
        }
        pathClockwise.add(end);
        
        // 计算逆时针路径
        List<Point> pathCounterClockwise = new ArrayList<>();
        pathCounterClockwise.add(start);
        curr = startEdgeIndex;
        while (curr != endEdgeIndex) {
            pathCounterClockwise.add(boundary.get(curr));
            curr = (curr - 1 + n) % n;
        }
        pathCounterClockwise.add(end);
        
        // 选择较短的路径
        List<Point> chosenPath = getPathLength(pathClockwise) < getPathLength(pathCounterClockwise) 
            ? pathClockwise : pathCounterClockwise;
        
        // 转换为路径段
        for (int i = 0; i < chosenPath.size() - 1; i++) {
            if (distance(chosenPath.get(i), chosenPath.get(i + 1)) > 1e-6) {
                result.add(new PathSegment(chosenPath.get(i), chosenPath.get(i + 1), false));
            }
        }
        
        return result;
    }
    
    /**
     * 计算路径总长度
     */
    private static double getPathLength(List<Point> path) {
        double len = 0;
        for (int i = 0; i < path.size() - 1; i++) {
            len += distance(path.get(i), path.get(i + 1));
        }
        return len;
    }
    
    /**
     * 判断两个点是否相同（考虑浮点误差）
     */
    private static boolean isSamePoint(Point a, Point b) {
        return Math.abs(a.x - b.x) < 1e-6 && Math.abs(a.y - b.y) < 1e-6;
    }
    
    /**
     * 判断两条线段是否相交（不包括端点）
     */
    private static boolean segmentsIntersect(Point a, Point b, Point c, Point d) {
        return ccw(a, c, d) != ccw(b, c, d) && ccw(a, b, c) != ccw(a, b, d);
    }
    
    /**
     * 判断三点是否逆时针排列
     */
    private static boolean ccw(Point a, Point b, Point c) {
        return (c.y - a.y) * (b.x - a.x) > (b.y - a.y) * (c.x - a.x);
    }
    
    /**
     * 交点信息内部类
     */
    private static class IntersectionInfo {
        Point point;        // 交点坐标
        int edgeIndex;      // 交点所在的边界边索引
        
        IntersectionInfo(Point point, int edgeIndex) {
            this.point = point;
            this.edgeIndex = edgeIndex;
        }
    }
    
    /**
     * 边界吸附结果内部类
     */
    private static class SnapResult {
        Point onEdge;       // 在边界上的投影点
        int edgeIndex;      // 所在的边界边索引
        
        SnapResult(Point p, int idx) {
            this.onEdge = p;
            this.edgeIndex = idx;
        }
    }
    
    /**
     * 计算点到边界最近的投影点以及所在边索引
     * @param p 要吸附的点
     * @param poly 边界多边形
     * @return 吸附结果
     */
    private static SnapResult snapToBoundary(Point p, List<Point> poly) {
        double minD = Double.MAX_VALUE;
        Point bestProj = p;
        int bestIdx = -1;
        for (int i = 0; i < poly.size(); i++) {
            Point s = poly.get(i);
            Point e = poly.get((i + 1) % poly.size());
            double l2 = (s.x - e.x) * (s.x - e.x) + (s.y - e.y) * (s.y - e.y);
            if (l2 < 1e-10) {
                double d = Math.hypot(p.x - s.x, p.y - s.y);
                if (d < minD) {
                    minD = d;
                    bestProj = s;
                    bestIdx = i;
                }
                continue;
            }
            double t = ((p.x - s.x) * (e.x - s.x) + (p.y - s.y) * (e.y - s.y)) / l2;
            t = Math.max(0, Math.min(1, t));
            Point proj = new Point(s.x + t * (e.x - s.x), s.y + t * (e.y - s.y));
            double d = Math.hypot(p.x - proj.x, p.y - proj.y);
            if (d < minD) {
                minD = d;
                bestProj = proj;
                bestIdx = i;
            }
        }
        return new SnapResult(bestProj, bestIdx == -1 ? 0 : bestIdx);
    }
    
    /**
     * 判断点是否在边界上（距离边界很近）
     * @param p 要检查的点
     * @param boundary 边界多边形
     * @return 是否在边界上
     */
    @SuppressWarnings("unused")
    private static boolean isPointOnBoundary(Point p, List<Point> boundary) {
        double threshold = 1e-4; // 阈值，考虑浮点误差
        for (int i = 0; i < boundary.size(); i++) {
            Point s = boundary.get(i);
            Point e = boundary.get((i + 1) % boundary.size());
            double dist = distToSegment(p, s, e);
            if (dist < threshold) {
                return true;
            }
        }
        return false;
    }
    
    /**
     * 计算点到线段的距离
     * @param p 点
     * @param s 线段起点
     * @param e 线段终点
     * @return 距离
     */
    private static double distToSegment(Point p, Point s, Point e) {
        double l2 = (s.x - e.x) * (s.x - e.x) + (s.y - e.y) * (s.y - e.y);
        if (l2 < 1e-10) {
            return Math.hypot(p.x - s.x, p.y - s.y);
        }
        double t = ((p.x - s.x) * (e.x - s.x) + (p.y - s.y) * (e.y - s.y)) / l2;
        t = Math.max(0, Math.min(1, t));
        return Math.hypot(p.x - (s.x + t * (e.x - s.x)), p.y - (s.y + t * (e.y - s.y)));
    }
    
    /**
     * 生成原始扫描路径（无障碍物版本）
     */
    private static List<PathSegment> generateGlobalScanPath(
            List<Point> polygon, double width, double angle, Point currentPos) {
        
        List<PathSegment> segments = new ArrayList<>();
        List<Point> rotatedPoly = new ArrayList<>();
        for (Point p : polygon) rotatedPoly.add(rotatePoint(p, -angle));
        
        double minY = Double.MAX_VALUE, maxY = -Double.MAX_VALUE;
        for (Point p : rotatedPoly) {
            minY = Math.min(minY, p.y);
            maxY = Math.max(maxY, p.y);
        }
        
        boolean leftToRight = true;
        for (double y = minY + width/2; y <= maxY - width/2; y += width) {
            List<Double> xIntersections = getXIntersections(rotatedPoly, y);
            if (xIntersections.size() < 2) continue;
            Collections.sort(xIntersections);
            
            List<PathSegment> lineSegmentsInRow = new ArrayList<>();
            for (int i = 0; i < xIntersections.size() - 1; i += 2) {
                Point pS = rotatePoint(new Point(xIntersections.get(i), y), angle);
                Point pE = rotatePoint(new Point(xIntersections.get(i + 1), y), angle);
                lineSegmentsInRow.add(new PathSegment(pS, pE, true));
            }
            
            if (!leftToRight) {
                Collections.reverse(lineSegmentsInRow);
                for (PathSegment s : lineSegmentsInRow) {
                    Point temp = s.start;
                    s.start = s.end;
                    s.end = temp;
                }
            }
            
            for (PathSegment s : lineSegmentsInRow) {
                if (distance(currentPos, s.start) > 0.01) {
                    segments.add(new PathSegment(currentPos, s.start, false));
                }
                segments.add(s);
                currentPos = s.end;
            }
            leftToRight = !leftToRight;
        }
        
        return segments;
    }
    
    /**
     * 解析障碍物字符串
     * 格式："(x1,y1;x2,y2)(x1,y1;x2,y2;x3,y3)"
     */
    private static List<Obstacle> parseObstacles(String obstaclesStr) {
        List<Obstacle> obstacles = new ArrayList<>();
        if (obstaclesStr == null || obstaclesStr.trim().isEmpty()) {
            return obstacles;
        }
        
        String trimmed = obstaclesStr.trim();
        List<String> obstacleStrs = new ArrayList<>();
        
        // 分割每个障碍物（用括号分隔）
        int start = trimmed.indexOf('(');
        while (start != -1) {
            int end = trimmed.indexOf(')', start);
            if (end == -1) break;
            
            String obsStr = trimmed.substring(start + 1, end);
            obstacleStrs.add(obsStr);
            start = trimmed.indexOf('(', end);
        }
        
        // 解析每个障碍物
        for (String obsStr : obstacleStrs) {
            List<Point> points = new ArrayList<>();
            String[] pairs = obsStr.split(";");
            
            for (String pair : pairs) {
                String[] xy = pair.split(",");
                if (xy.length == 2) {
                    points.add(new Point(
                        Double.parseDouble(xy[0].trim()),
                        Double.parseDouble(xy[1].trim())
                    ));
                }
            }
            
            if (points.size() == 2) {
                // 圆形障碍物：第一个点为圆心，第二个点为圆上一点
                Point center = points.get(0);
                Point onCircle = points.get(1);
                double radius = distance(center, onCircle);
                obstacles.add(new Obstacle(center, radius));
            } else if (points.size() > 2) {
                // 多边形障碍物
                obstacles.add(new Obstacle(points));
            }
        }
        
        return obstacles;
    }
    
    /**
     * 外扩障碍物（增加安全边距）
     */
    private static List<Obstacle> expandObstacles(List<Obstacle> obstacles, double margin) {
        List<Obstacle> expanded = new ArrayList<>();
        
        for (Obstacle obs : obstacles) {
            if (obs.isCircle()) {
                // 圆形：半径增加安全边距
                expanded.add(new Obstacle(obs.center, obs.radius + margin));
            } else {
                // 多边形：向外偏移（与边界内缩方向相反）
                List<Point> expandedPoints = getOutsetPolygon(obs.points, margin);
                expanded.add(new Obstacle(expandedPoints));
            }
        }
        
        return expanded;
    }
    
    /**
     * 多边形外扩（与内缩方向相反）
     */
    private static List<Point> getOutsetPolygon(List<Point> points, double margin) {
        // 这里使用简化的外扩方法：沿法线向外移动
        List<Point> outset = new ArrayList<>();
        int n = points.size();
        
        for (int i = 0; i < n; i++) {
            Point pPrev = points.get((i - 1 + n) % n);
            Point pCurr = points.get(i);
            Point pNext = points.get((i + 1) % n);
            
            // 计算两个边的向量
            double v1x = pCurr.x - pPrev.x, v1y = pCurr.y - pPrev.y;
            double v2x = pNext.x - pCurr.x, v2y = pNext.y - pCurr.y;
            
            // 计算法线（确保向外）
            double nx1 = -v1y, ny1 = v1x;
            double nx2 = -v2y, ny2 = v2x;
            
            // 归一化
            double len1 = Math.hypot(nx1, ny1);
            double len2 = Math.hypot(nx2, ny2);
            if (len1 > 1e-6) { nx1 /= len1; ny1 /= len1; }
            if (len2 > 1e-6) { nx2 /= len2; ny2 /= len2; }
            
            // 计算平均法线方向
            double nx = (nx1 + nx2) / 2;
            double ny = (ny1 + ny2) / 2;
            double len = Math.hypot(nx, ny);
            if (len > 1e-6) {
                nx /= len;
                ny /= len;
            }
            
            // 向外移动
            outset.add(new Point(
                pCurr.x + nx * margin,
                pCurr.y + ny * margin
            ));
        }
        
        return outset;
    }
    
    /**
     * 障碍物类
     */
    private static class Obstacle {
        List<Point> points; // 多边形顶点（对圆形为空）
        Point center;       // 圆心（仅对圆形有效）
        double radius;      // 半径（仅对圆形有效）
        boolean isCircle;
        
        // 多边形构造函数
        Obstacle(List<Point> points) {
            this.points = new ArrayList<>(points);
            this.isCircle = false;
            ensureCounterClockwise(this.points); // 确保顺时针（对障碍物是内部区域）
        }
        
        // 圆形构造函数
        Obstacle(Point center, double radius) {
            this.center = new Point(center.x, center.y);
            this.radius = radius;
            this.isCircle = true;
            this.points = new ArrayList<>();
        }
        
        // 判断点是否在障碍物内部
        boolean contains(Point p) {
            if (isCircle) {
                return distance(p, center) <= radius;
            } else {
                return isPointInPolygon(p, points);
            }
        }
        
        // 获取线段与障碍物的交点
        List<Point> getIntersections(PathSegment segment) {
            List<Point> intersections = new ArrayList<>();
            
            if (isCircle) {
                // 线段与圆的交点
                double dx = segment.end.x - segment.start.x;
                double dy = segment.end.y - segment.start.y;
                double a = dx * dx + dy * dy;
                double b = 2 * (dx * (segment.start.x - center.x) + 
                               dy * (segment.start.y - center.y));
                double c = (segment.start.x - center.x) * (segment.start.x - center.x) + 
                          (segment.start.y - center.y) * (segment.start.y - center.y) - 
                          radius * radius;
                
                double discriminant = b * b - 4 * a * c;
                if (discriminant >= 0) {
                    discriminant = Math.sqrt(discriminant);
                    for (int sign = -1; sign <= 1; sign += 2) {
                        double t = (-b + sign * discriminant) / (2 * a);
                        if (t >= 0 && t <= 1) {
                            intersections.add(new Point(
                                segment.start.x + t * dx,
                                segment.start.y + t * dy
                            ));
                        }
                    }
                }
            } else {
                // 线段与多边形的交点
                for (int i = 0; i < points.size(); i++) {
                    Point p1 = points.get(i);
                    Point p2 = points.get((i + 1) % points.size());
                    
                    Point inter = getLineIntersection(
                        segment.start, segment.end, p1, p2);
                    if (inter != null) {
                        intersections.add(inter);
                    }
                }
            }
            
            return intersections;
        }
        
        boolean isCircle() {
            return isCircle;
        }
    }
    
    /**
     * 判断点是否在多边形内部（射线法）
     */
    private static boolean isPointInPolygon(Point p, List<Point> polygon) {
        boolean inside = false;
        for (int i = 0, j = polygon.size() - 1; i < polygon.size(); j = i++) {
            Point pi = polygon.get(i);
            Point pj = polygon.get(j);
            
            if (((pi.y > p.y) != (pj.y > p.y)) &&
                (p.x < (pj.x - pi.x) * (p.y - pi.y) / (pj.y - pi.y) + pi.x)) {
                inside = !inside;
            }
        }
        return inside;
    }
    
    /**
     * 计算两条线段的交点
     */
    private static Point getLineIntersection(Point p1, Point p2, Point p3, Point p4) {
        double denom = (p1.x - p2.x) * (p3.y - p4.y) - (p1.y - p2.y) * (p3.x - p4.x);
        if (Math.abs(denom) < 1e-6) return null; // 平行
        
        double t = ((p1.x - p3.x) * (p3.y - p4.y) - (p1.y - p3.y) * (p3.x - p4.x)) / denom;
        double u = -((p1.x - p2.x) * (p1.y - p3.y) - (p1.y - p2.y) * (p1.x - p3.x)) / denom;
        
        if (t >= 0 && t <= 1 && u >= 0 && u <= 1) {
            return new Point(
                p1.x + t * (p2.x - p1.x),
                p1.y + t * (p2.y - p1.y)
            );
        }
        return null;
    }
    
    /**
     * 计算两点距离
     */
    private static double distance(Point p1, Point p2) {
        return Math.hypot(p1.x - p2.x, p1.y - p2.y);
    }
    
    // ============ 以下是从A代码复用的方法 ============
    
    private static Point getFirstScanPoint(List<Point> polygon, double width, double angle) {
        List<Point> rotatedPoly = new ArrayList<>();
        for (Point p : polygon) rotatedPoly.add(rotatePoint(p, -angle));
        double minY = Double.MAX_VALUE;
        for (Point p : rotatedPoly) minY = Math.min(minY, p.y);
        
        double firstY = minY + width/2;
        List<Double> xInter = getXIntersections(rotatedPoly, firstY);
        if (xInter.isEmpty()) return polygon.get(0);
        Collections.sort(xInter);
        return rotatePoint(new Point(xInter.get(0), firstY), angle);
    }
    
    private static List<Point> alignBoundaryStart(List<Point> boundary, Point targetStart) {
        int bestIdx = 0;
        double minDist = Double.MAX_VALUE;
        for (int i = 0; i < boundary.size(); i++) {
            double d = Math.hypot(boundary.get(i).x - targetStart.x, boundary.get(i).y - targetStart.y);
            if (d < minDist) { minDist = d; bestIdx = i; }
        }
        List<Point> aligned = new ArrayList<>();
        for (int i = 0; i < boundary.size(); i++) {
            aligned.add(boundary.get((bestIdx + i) % boundary.size()));
        }
        return aligned;
    }
    
    private static List<Double> getXIntersections(List<Point> rotatedPoly, double y) {
        List<Double> xIntersections = new ArrayList<>();
        for (int i = 0; i < rotatedPoly.size(); i++) {
            Point p1 = rotatedPoly.get(i);
            Point p2 = rotatedPoly.get((i + 1) % rotatedPoly.size());
            if ((p1.y <= y && p2.y > y) || (p2.y <= y && p1.y > y)) {
                double x = p1.x + (y - p1.y) * (p2.x - p1.x) / (p2.y - p1.y);
                xIntersections.add(x);
            }
        }
        return xIntersections;
    }
    
    private static double findOptimalAngle(List<Point> polygon) {
        double bestAngle = 0;
        double minHeight = Double.MAX_VALUE;
        for (int i = 0; i < polygon.size(); i++) {
            Point p1 = polygon.get(i), p2 = polygon.get((i + 1) % polygon.size());
            double angle = Math.atan2(p2.y - p1.y, p2.x - p1.x);
            double h = calculateHeightAtAngle(polygon, angle);
            if (h < minHeight) { minHeight = h; bestAngle = angle; }
        }
        return bestAngle;
    }
    
    private static double calculateHeightAtAngle(List<Point> poly, double angle) {
        double minY = Double.MAX_VALUE, maxY = -Double.MAX_VALUE;
        for (Point p : poly) {
            Point rp = rotatePoint(p, -angle);
            minY = Math.min(minY, rp.y); maxY = Math.max(maxY, rp.y);
        }
        return maxY - minY;
    }
    
    private static List<Point> getInsetPolygon(List<Point> points, double margin) {
        List<Point> result = new ArrayList<>();
        int n = points.size();
        for (int i = 0; i < n; i++) {
            Point pPrev = points.get((i - 1 + n) % n);
            Point pCurr = points.get(i);
            Point pNext = points.get((i + 1) % n);

            double d1x = pCurr.x - pPrev.x, d1y = pCurr.y - pPrev.y;
            double l1 = Math.hypot(d1x, d1y);
            double d2x = pNext.x - pCurr.x, d2y = pNext.y - pCurr.y;
            double l2 = Math.hypot(d2x, d2y);

            if (l1 < 1e-6 || l2 < 1e-6) continue;

            double n1x = -d1y / l1, n1y = d1x / l1;
            double n2x = -d2y / l2, n2y = d2x / l2;

            double bisectorX = n1x + n2x, bisectorY = n1y + n2y;
            double bLen = Math.hypot(bisectorX, bisectorY);
            if (bLen < 1e-6) { bisectorX = n1x; bisectorY = n1y; } 
            else { bisectorX /= bLen; bisectorY /= bLen; }

            double cosHalfAngle = n1x * bisectorX + n1y * bisectorY;
            double dist = margin / Math.max(cosHalfAngle, 0.1); 
            
            dist = Math.min(dist, margin * 5);

            result.add(new Point(pCurr.x + bisectorX * dist, pCurr.y + bisectorY * dist));
        }
        return result;
    }
    
    private static Point rotatePoint(Point p, double angle) {
        double cos = Math.cos(angle), sin = Math.sin(angle);
        return new Point(p.x * cos - p.y * sin, p.x * sin + p.y * cos);
    }
    
    private static void ensureCounterClockwise(List<Point> points) {
        double sum = 0;
        for (int i = 0; i < points.size(); i++) {
            Point p1 = points.get(i), p2 = points.get((i + 1) % points.size());
            sum += (p2.x - p1.x) * (p2.y + p1.y);
        }
        if (sum > 0) Collections.reverse(points);
    }
    
    private static List<Point> parseCoordinates(String coordinates) {
        List<Point> points = new ArrayList<>();
        String[] pairs = coordinates.split(";");
        for (String pair : pairs) {
            String[] xy = pair.split(",");
            if (xy.length == 2) points.add(new Point(Double.parseDouble(xy[0]), Double.parseDouble(xy[1])));
        }
        if (points.size() > 1 && points.get(0).equals(points.get(points.size()-1))) points.remove(points.size()-1);
        return points;
    }
    
    /**
     * 打印输出路径坐标到控制台
     */
    private static void printPathCoordinates(List<PathSegment> path) {
        if (path == null || path.isEmpty()) {
            System.out.println("路径为空");
            return;
        }
        
        System.out.println("========== 路径坐标输出 ==========");
        System.out.println("总路径段数: " + path.size());
        System.out.println();
        System.out.println("路径坐标序列 (格式: x,y;x,y;...):");
        
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < path.size(); i++) {
            PathSegment segment = path.get(i);
            if (i == 0) {
                // 第一个段的起点
                sb.append(String.format("%.2f,%.2f", segment.start.x, segment.start.y));
            }
            // 每个段的终点
            sb.append(";");
            sb.append(String.format("%.2f,%.2f", segment.end.x, segment.end.y));
        }
        
        System.out.println(sb.toString());
        System.out.println();
        System.out.println("详细路径信息:");
        for (int i = 0; i < path.size(); i++) {
            PathSegment segment = path.get(i);
            String type = segment.isMowing ? "割草" : "空走";
            System.out.println(String.format("段 %d [%s]: (%.2f,%.2f) -> (%.2f,%.2f)", 
                i + 1, type, segment.start.x, segment.start.y, segment.end.x, segment.end.y));
        }
        System.out.println("==================================");
    }
    
    public static class Point {
        public double x, y;
        public Point(double x, double y) { this.x = x; this.y = y; }
        @Override
        public boolean equals(Object o) {
            if (!(o instanceof Point)) return false;
            Point p = (Point) o;
            return Math.abs(x - p.x) < 1e-4 && Math.abs(y - p.y) < 1e-4;
        }
    }
    
    public static class PathSegment {
        public Point start, end;
        public boolean isMowing;
        public PathSegment(Point s, Point e, boolean m) { 
            this.start = s; 
            this.end = e; 
            this.isMowing = m; 
        }
    }
}