task(C1): render adapter interface with headless mock adapter

frontend/src/render/mock/MockAdapter.ts

@@ -0,0 +1,115 @@
+/**
+ * MockAdapter – Headless-Implementierung des RenderAdapter (Task C1).
+ * Zeichnet nichts; protokolliert alle Aufrufe für assertions in Unit-Tests.
+ */
+import type {
+  RenderAdapter,
+  Viewport,
+  GridConfig,
+  BackgroundDrawConfig,
+  RulerConfig,
+  LayerStyle,
+  OverlayPainter,
+  SelectionState,
+} from '../types';
+import type { CADElement, CADLayer } from '../../types/cad.types';
+import type { Pt } from '../../tools/modification/geometry';
+
+export interface RecordedCall {
+  method: string;
+  args: unknown[];
+}
+
+export class MockAdapter implements RenderAdapter {
+  readonly calls: RecordedCall[] = [];
+  private canvas: HTMLCanvasElement | null = null;
+  nextHitTestResult: CADElement | null = null;
+
+  // ── Recording helper ─────────────────────────────────────
+
+  private rec(method: string, args: unknown[]): void {
+    this.calls.push({ method, args });
+  }
+
+  /** Test-Helfer: alle Aufrufe einer Methode. */
+  callsOf(method: string): RecordedCall[] {
+    return this.calls.filter((c) => c.method === method);
+  }
+
+  /** Test-Helfer: Anzahl Aufrufe einer Methode. */
+  countCalls(method: string): number {
+    return this.callsOf(method).length;
+  }
+
+  reset(): void {
+    this.calls.length = 0;
+    this.nextHitTestResult = null;
+  }
+
+  // ── RenderAdapter Implementierung (reines Recording) ─────
+
+  init(canvas: HTMLCanvasElement): void {
+    this.canvas = canvas;
+    this.rec('init', [canvas]);
+  }
+
+  resize(width: number, height: number, dpr: number): void {
+    this.rec('resize', [width, height, dpr]);
+  }
+
+  setViewport(vp: Viewport): void {
+    this.rec('setViewport', [vp]);
+  }
+
+  destroy(): void {
+    this.rec('destroy', []);
+  }
+
+  clear(color: string): void {
+    this.rec('clear', [color]);
+  }
+
+  drawGrid(cfg: GridConfig): void {
+    this.rec('drawGrid', [cfg]);
+  }
+
+  drawBackground(img: HTMLImageElement | null, cfg: BackgroundDrawConfig): void {
+    this.rec('drawBackground', [img, cfg]);
+  }
+
+  drawRuler(cfg: RulerConfig): void {
+    this.rec('drawRuler', [cfg]);
+  }
+
+  drawElement(el: CADElement, layer: CADLayer, style: LayerStyle): void {
+    this.rec('drawElement', [el, layer, style]);
+  }
+
+  drawPreview(el: CADElement | null): void {
+    this.rec('drawPreview', [el]);
+  }
+
+  setSelection(sel: SelectionState): void {
+    this.rec('setSelection', [sel]);
+  }
+
+  setSnapPoints(pts: Array<{ x: number; y: number; type: string }>): void {
+    this.rec('setSnapPoints', [pts]);
+  }
+
+  overlay(draw: (g: OverlayPainter) => void): void {
+    const painter: OverlayPainter = {
+      line(a: Pt, b: Pt, color: string, width?: number) {},
+      rect(x: number, y: number, w: number, h: number, strokeColor: string) {},
+      circle(center: Pt, radius: number, strokeColor: string) {},
+      text(text: string, at: Pt, color: string, fontSize?: number) {},
+    };
+    draw(painter);
+    this.rec('overlay', [null]);
+  }
+
+  hitTest(world: Pt, tolerancePx: number): CADElement | null {
+    this.rec('hitTest', [world, tolerancePx]);
+    return this.nextHitTestResult;
+  }
+}