/**
 * MoveDashedLine.ts
 * Author: David de ShineYoung
 * Creation Date: 2025/10/27
 * Description: 绘制带箭头指示的虚线移动路径
 *
 */
import { _decorator, Component, Graphics, Vec3, Color, Vec2 } from 'cc';
const { ccclass, property } = _decorator;

const _arrowDir = new Vec3();
const _arrowCenter = new Vec3();
const _arrowTip = new Vec3();
const _arrowLeft = new Vec3();
const _arrowRight = new Vec3();
const _leftOffset = new Vec3();
const _rightOffset = new Vec3();
const _segStart = new Vec3();
const _segEnd = new Vec3();

@ccclass('MoveDashedLine')
export class MoveDashedLine extends Component {
    
    @property(Graphics)
    graphics: Graphics = null!;
    
    @property([Vec2])
    paths: Vec2[] = [];
    
    @property
    dashLength: number = 10; // 虚线每段长度
    
    @property
    gapLength: number = 8; // 虚线间隙长度
    
    @property
    lineWidth: number = 2; // 线宽
    
    @property(Color)
    lineColor: Color = Color.WHITE; // 线条颜色
    
    @property
    moveSpeed: number = 3; // 移动速度
    
    @property
    arrowCount: number = 3; // 箭头数量
    
    @property
    arrowSize: number = 20; // 箭头大小
    
    @property
    arrowSpacingFactor: number = 20; // 箭头间距因子，值越大间距越大
    
    private _currentOffset: number = 0;
    private _totalPathLength: number = 0;
    private _pathSegments: { start: Vec3; end: Vec3; length: number }[] = [];
    /** 引导线固定两点，setPathEndpoints 复用 */
    private _pathA = new Vec2();
    private _pathB = new Vec2();
    
    onLoad() {
        this.calculatePathData();
    }
    
    start() {
        
    }
    
    setLineColor(color: Color) {
        this.lineColor = color;
    }
    
    startSchedule() {
        this.schedule(this.updateLine); // 约60帧
    }
    
    private calculatePathData() {
        this._pathSegments.length = 0;
        this._totalPathLength = 0;
        
        for (let i = 0; i < this.paths.length - 1; i++) {
            const p0 = this.paths[i];
            const p1 = this.paths[i + 1];
            _segStart.set(p0.x, p0.y, 0);
            _segEnd.set(p1.x, p1.y, 0);
            const length = Vec3.distance(_segStart, _segEnd);
            
            this._pathSegments.push({
                start: _segStart.clone(),
                end: _segEnd.clone(),
                length,
            });
            
            this._totalPathLength += length;
        }
    }
    
    private updateLine() {
        this._currentOffset += this.moveSpeed;
        // 当偏移超过路径长度时，循环
        if (this._currentOffset > this._totalPathLength) {
            this._currentOffset = 0;
        }
        this.drawArrows();
    }
    
    
     // 绘制箭头>
    private drawArrows() {
        if (!this.graphics || this._pathSegments.length === 0) return;
            
            // 清除之前的绘制内容
            this.graphics.clear();
            
            this.graphics.lineWidth = this.lineWidth;
            this.graphics.strokeColor = this.lineColor;
            this.graphics.fillColor = this.lineColor;
        // 使用arrowSpacingFactor作为箭头之间的最小间距（像素单位）
        const minArrowSpacing = Math.max(this.arrowSpacingFactor, this.arrowSize * 0.8);
        
        // 计算需要绘制的箭头数量
        // 从起点开始绘制，每隔minArrowSpacing距离绘制一个箭头，直到终点
        const totalArrows = Math.max(1, Math.floor(this._totalPathLength / minArrowSpacing));
        
        // 计算实际的间距，确保箭头均匀分布在整个路径上
        const actualSpacing = this._totalPathLength / totalArrows;
        
        for (let i = 0; i <= totalArrows; i++) {
            // 计算箭头位置：从起点到终点均匀分布
            const arrowPosition = (this._currentOffset + actualSpacing * i) % this._totalPathLength;
            this.drawArrowAtPosition(arrowPosition);
        }
    }
    
    // 在指定位置绘制箭头>
    private drawArrowAtPosition(position: number) {
        if (!this.graphics) return;
        
        let accumulatedLength = 0;
        for (const segment of this._pathSegments) {
            if (accumulatedLength + segment.length > position) {
                const arrowSegmentPosition = position - accumulatedLength;
                Vec3.subtract(_arrowDir, segment.end, segment.start);
                Vec3.normalize(_arrowDir, _arrowDir);
                
                Vec3.multiplyScalar(_arrowCenter, _arrowDir, arrowSegmentPosition);
                Vec3.add(_arrowCenter, segment.start, _arrowCenter);
                
                const perpX = -_arrowDir.y;
                const perpY = _arrowDir.x;
                
                const arrowSize = this.arrowSize;
                const halfWidth = arrowSize * 0.3;
                
                Vec3.multiplyScalar(_arrowTip, _arrowDir, arrowSize * 0.5);
                Vec3.add(_arrowTip, _arrowCenter, _arrowTip);
                
                Vec3.multiplyScalar(_arrowLeft, _arrowDir, -arrowSize * 0.3);
                Vec3.add(_arrowLeft, _arrowCenter, _arrowLeft);
                _leftOffset.set(perpX * halfWidth, perpY * halfWidth, 0);
                Vec3.add(_arrowLeft, _arrowLeft, _leftOffset);
                
                Vec3.multiplyScalar(_arrowRight, _arrowDir, -arrowSize * 0.3);
                Vec3.add(_arrowRight, _arrowCenter, _arrowRight);
                _rightOffset.set(perpX * -halfWidth, perpY * -halfWidth, 0);
                Vec3.add(_arrowRight, _arrowRight, _rightOffset);
                
                this.graphics.moveTo(_arrowTip.x, _arrowTip.y);
                this.graphics.lineTo(_arrowLeft.x, _arrowLeft.y);
                this.graphics.lineTo(_arrowRight.x, _arrowRight.y);
                this.graphics.close();
                this.graphics.fill();
                
                break;
            }
            accumulatedLength += segment.length;
        }
    }

    /** 更新两端点（复用内部 Vec2，避免引导每帧 new） */
    public setPathEndpoints(x1: number, y1: number, x2: number, y2: number): void {
        this._pathA.set(x1, y1);
        this._pathB.set(x2, y2);
        if (this.paths.length !== 2 || this.paths[0] !== this._pathA || this.paths[1] !== this._pathB) {
            this.paths = [this._pathA, this._pathB];
        }
        this.calculatePathData();
        this._currentOffset = 0;
        this.arrowSpacingFactor = 50;
        this.drawArrows();
    }

    // 设置新的路径点
    public setPaths(newPaths: Vec2[]) {
        this.paths = newPaths;
        this.calculatePathData();
        this._currentOffset = 0;
        this.arrowSpacingFactor = 50;
        this.drawArrows();
       
    }
    
    // 设置移动速度
    public setMoveSpeed(speed: number) {
        this.moveSpeed = speed;
    }
    
    onDestroy() {
        this.unschedule(this.updateLine);
    }
}