refactor: use path builder

blocksuite/affine/gfx/connector/src/element-renderer/connector-dom/index.ts

@@ -17,6 +17,60 @@ interface PathBounds {
   maxY: number;
 }
 
+interface PathCommand {
+  command: string;
+  coordinates: number[];
+}
+
+class SVGPathBuilder {
+  private commands: PathCommand[] = [];
+
+  moveTo(x: number, y: number): this {
+    this.commands.push({
+      command: 'M',
+      coordinates: [x, y],
+    });
+    return this;
+  }
+
+  lineTo(x: number, y: number): this {
+    this.commands.push({
+      command: 'L',
+      coordinates: [x, y],
+    });
+    return this;
+  }
+
+  curveTo(
+    cp1x: number,
+    cp1y: number,
+    cp2x: number,
+    cp2y: number,
+    x: number,
+    y: number
+  ): this {
+    this.commands.push({
+      command: 'C',
+      coordinates: [cp1x, cp1y, cp2x, cp2y, x, y],
+    });
+    return this;
+  }
+
+  build(): string {
+    const pathSegments = this.commands.map(cmd => {
+      const coords = cmd.coordinates.join(' ');
+      return `${cmd.command} ${coords}`;
+    });
+
+    return pathSegments.join(' ');
+  }
+
+  clear(): this {
+    this.commands = [];
+    return this;
+  }
+}
+
 function calculatePathBounds(path: PointLocation[]): PathBounds {
   if (path.length === 0) {
     return { minX: 0, minY: 0, maxX: 0, maxY: 0 };
@@ -43,23 +97,31 @@ function createConnectorPath(
 ): string {
   if (points.length < 2) return '';
 
-  let pathData = `M ${points[0][0]} ${points[0][1]}`;
+  const pathBuilder = new SVGPathBuilder();
+  pathBuilder.moveTo(points[0][0], points[0][1]);
 
   if (mode === ConnectorMode.Curve) {
     // Use bezier curves
     for (let i = 1; i < points.length; i++) {
       const prev = points[i - 1];
       const curr = points[i];
-      pathData += ` C ${prev.absOut[0]} ${prev.absOut[1]} ${curr.absIn[0]} ${curr.absIn[1]} ${curr[0]} ${curr[1]}`;
+      pathBuilder.curveTo(
+        prev.absOut[0],
+        prev.absOut[1],
+        curr.absIn[0],
+        curr.absIn[1],
+        curr[0],
+        curr[1]
+      );
     }
   } else {
     // Use straight lines
     for (let i = 1; i < points.length; i++) {
-      pathData += ` L ${points[i][0]} ${points[i][1]}`;
+      pathBuilder.lineTo(points[i][0], points[i][1]);
     }
   }
 
-  return pathData;
+  return pathBuilder.build();
 }
 
 function createArrowMarker(