selecting and wiring

editor/eslint.config.js

@@ -11,12 +11,18 @@ export default defineConfig([
     files: ['**/*.{ts,tsx}'],
     extends: [
       js.configs.recommended,
-      tseslint.configs.recommended,
+      tseslint.configs.recommendedTypeChecked,
       reactHooks.configs.flat.recommended,
       reactRefresh.configs.vite,
     ],
     languageOptions: {
       globals: globals.browser,
+      parserOptions: {
+        projectService: true,
+      }
     },
+    rules: {
+      "@typescript-eslint/no-unused-vars": "off"
+    }
   },
 ])

editor/src/editor/Board.ts

@@ -1,25 +1,61 @@
+import type { Selection } from "./Cx";
 import type { Renderer } from "./Renderer";
 import { pointInsideRect, rectsCollide, v2, V2 } from "./V2";
 
 export class Board {
-  private components: Component[] = [];
+  private components: PlacedComponent[] = [];
 
-  private hoveredOverInput: [Component, number] | null = null;
+  private hoveredOverInput: [PlacedComponent, number] | null = null;
-  private hoveredOverOutput: [Component, number] | null = null;
+  private hoveredOverOutput: [PlacedComponent, number] | null = null;
 
-  canPlaceComponent(def: ComponentDef, pos: V2): boolean {
+  constructor() {}
+
+  canPlaceComponent(kind: ComponentKind, pos: V2): boolean {
     return !this.components.some((comp) =>
-      rectsCollide(comp.pos, comp.def.size, pos, def.size),
+      rectsCollide(comp.pos, comp.kind.size, pos, kind.size),
     );
   }
 
-  placeComponent(def: ComponentDef, pos: V2) {
+  placeComponent(kind: ComponentKind, pos: V2) {
-    this.components.push({ def, pos });
+    this.components.push({ kind: kind, pos });
   }
 
-  render(r: Renderer) {
+  render(r: Renderer, selection: Selection | null) {
     for (const comp of this.components) {
-      r.drawComponent(comp, this.hoveredOverInput, this.hoveredOverOutput);
+      const { pos, kind } = comp;
+      if (selection?.isComponentSelected(comp)) {
+        r.drawComponentBodySelected(pos, kind);
+      } else {
+        r.drawComponentBody(pos, kind);
+      }
+
+      for (const { i, pinOffset } of kind.inputPinIter()) {
+        if (kind.inputs[i] !== null) {
+          throw new Error("pin text not implemented");
+        }
+        r.drawComponentInputPin(pos, pinOffset);
+
+        if (
+          this.hoveredOverInput?.[0] === comp &&
+          this.hoveredOverInput[1] === i
+        ) {
+          r.drawComponentInputPinHover(pos, pinOffset);
+        }
+      }
+
+      for (const { i, pinOffset } of kind.outputPinIter()) {
+        if (kind.outputs[i] !== null) {
+          throw new Error("pin text not implemented");
+        }
+        r.drawComponentOutputPin(pos, kind, pinOffset);
+
+        if (
+          this.hoveredOverOutput?.[0] === comp &&
+          this.hoveredOverOutput[1] === i
+        ) {
+          r.drawComponentOutputPinHover(pos, kind, pinOffset);
+        }
+      }
     }
   }
 
@@ -30,10 +66,8 @@ export class Board {
     for (const comp of this.components) {
       const {
         pos: { x, y },
-        def: {
+        kind: {
-          size: { x: w, y: h },
+          size: { x: w },
-          inputs,
-          outputs,
         },
       } = comp;
 
@@ -41,43 +75,35 @@ export class Board {
         !pointInsideRect(
           pos,
           comp.pos.sub(v2(5, 5)),
-          comp.def.size.add(v2(10, 10)),
+          comp.kind.size.add(v2(10, 10)),
         )
       ) {
         continue;
       }
-      {
+      for (const { i, pinOffset } of comp.kind.inputPinIter()) {
-        const pinSpace = h / (inputs.length + 1);
+        if (v2(x, y + pinOffset).distance(pos) < 6) {
-        for (let i = 0; i < inputs.length; ++i) {
-          if (v2(x, y + (i + 1) * pinSpace).distance(pos) < 5) {
           this.hoveredOverInput = [comp, i];
         }
       }
-      }
+      for (const { i, pinOffset } of comp.kind.outputPinIter()) {
-      {
+        if (v2(x + w, y + pinOffset).distance(pos) < 6) {
-        const pinSpace = h / (outputs.length + 1);
-        for (let i = 0; i < outputs.length; ++i) {
-          if (v2(x + w, y + (i + 1) * pinSpace).distance(pos) < 5) {
           this.hoveredOverOutput = [comp, i];
         }
       }
     }
   }
-  }
 
   handleMouseClick(
     pos: V2,
-    inputPinClicked: (comp: Component, i: number) => void,
+    inputPinClicked: (comp: PlacedComponent, i: number) => void,
-    outputPinClicked: (comp: Component, i: number) => void,
+    outputPinClicked: (comp: PlacedComponent, i: number) => void,
-    componentClicked: (comp: Component) => void,
+    componentClicked: (comp: PlacedComponent) => void,
   ): "handled" | "not handled" {
     for (const comp of this.components) {
       const {
         pos: { x, y },
-        def: {
+        kind: {
-          size: { x: w, y: h },
+          size: { x: w },
-          inputs,
-          outputs,
         },
       } = comp;
 
@@ -85,97 +111,118 @@ export class Board {
         !pointInsideRect(
           pos,
           comp.pos.sub(v2(5, 5)),
-          comp.def.size.add(v2(10, 10)),
+          comp.kind.size.add(v2(10, 10)),
         )
       ) {
         continue;
       }
-      {
+      for (const { i, pinOffset } of comp.kind.inputPinIter()) {
-        const pinSpace = h / (inputs.length + 1);
+        if (v2(x, y + pinOffset).distance(pos) < 6) {
-        for (let i = 0; i < inputs.length; ++i) {
-          if (v2(x, y + (i + 1) * pinSpace).distance(pos) < 5) {
           inputPinClicked(comp, i);
           return "handled";
         }
       }
-      }
+      for (const { i, pinOffset } of comp.kind.outputPinIter()) {
-      {
+        if (v2(x + w, y + pinOffset).distance(pos) < 6) {
-        const pinSpace = h / (outputs.length + 1);
-        for (let i = 0; i < outputs.length; ++i) {
-          if (v2(x + w, y + (i + 1) * pinSpace).distance(pos) < 5) {
           outputPinClicked(comp, i);
           return "handled";
         }
       }
-      }
       componentClicked(comp);
       return "handled";
     }
     return "not handled";
   }
+
+  componentsInRect(pos: V2, size: V2): PlacedComponent[] {
+    return this.components.filter((comp) =>
+      rectsCollide(pos, size, comp.pos, comp.kind.size),
+    );
+  }
 }
 
 export class ComponentRepo {
-  private defs = new Map<string, ComponentDef>();
+  private defs = new Map<string, ComponentKind>();
 
   static withDefaults(): ComponentRepo {
     const repo = new ComponentRepo();
 
-    repo.add("input", {
+    for (const { label, size, inputs, outputs } of defaultDefs) {
-      label: "input",
+      repo.add(label, new ComponentKind(size, label, inputs, outputs));
-      size: v2(80, 40),
+    }
-      inputs: [],
-      outputs: [null],
-    });
-    repo.add("output", {
-      label: "output",
-      size: v2(80, 40),
-      inputs: [null],
-      outputs: [],
-    });
-    repo.add("and", {
-      label: "and",
-      size: v2(80, 40),
-      inputs: [null, null],
-      outputs: [null],
-    });
-    repo.add("or", {
-      label: "or",
-      size: v2(80, 40),
-      inputs: [null, null],
-      outputs: [null],
-    });
-    repo.add("not", {
-      label: "not",
-      size: v2(80, 40),
-      inputs: [null],
-      outputs: [null],
-    });
 
     return repo;
   }
 
-  add(ident: string, def: ComponentDef) {
+  add(ident: string, kind: ComponentKind) {
-    this.defs.set(ident, def);
+    this.defs.set(ident, kind);
   }
 
-  get(ident: string): ComponentDef {
+  get(ident: string): ComponentKind {
-    const def = this.defs.get(ident);
+    const kind = this.defs.get(ident);
-    if (!def) {
+    if (!kind) {
       throw new Error("should be defined");
     }
-    return def;
+    return kind;
   }
 }
 
-export type Component = {
+export type PlacedComponent = {
-  def: ComponentDef;
+  kind: ComponentKind;
   pos: V2;
 };
 
-export type ComponentDef = {
+export class ComponentKind {
-  size: V2;
+  constructor(
-  label: string;
+    public size: V2,
-  inputs: (string | null)[];
+    public label: string,
-  outputs: (string | null)[];
+    public inputs: (string | null)[],
-};
+    public outputs: (string | null)[],
+  ) {}
+
+  inputPinIter(): { i: number; pinOffset: number }[] {
+    return this.inputs.map((_, i) => ({
+      i,
+      pinOffset: ((i + 1) * this.size.y) / (this.inputs.length + 1),
+    }));
+  }
+  outputPinIter(): { i: number; pinOffset: number }[] {
+    return this.outputs.map((_, i) => ({
+      i,
+      pinOffset: ((i + 1) * this.size.y) / (this.outputs.length + 1),
+    }));
+  }
+}
+
+const defaultDefs = [
+  {
+    label: "input",
+    size: v2(80, 40),
+    inputs: [],
+    outputs: [null],
+  },
+  {
+    label: "output",
+    size: v2(80, 40),
+    inputs: [null],
+    outputs: [],
+  },
+  {
+    label: "and",
+    size: v2(80, 40),
+    inputs: [null, null],
+    outputs: [null],
+  },
+  {
+    label: "or",
+    size: v2(80, 40),
+    inputs: [null, null],
+    outputs: [null],
+  },
+  {
+    label: "not",
+    size: v2(80, 40),
+    inputs: [null],
+    outputs: [null],
+  },
+];

editor/src/editor/Cx.ts

@@ -1,28 +1,35 @@
-import { Board, ComponentRepo } from "./Board";
+import { Board, ComponentRepo, type PlacedComponent } from "./Board";
 import { Renderer } from "./Renderer";
 import * as states from "./states";
 import { v2, V2 } from "./V2";
 
+export type Tool = string;
+
 export class Cx {
   public offset = v2(0, 0);
   private renderNeeded = false;
   private state = new states.Normal(this) as states.State;
   private updateActions: (() => void)[] = [];
 
-  private selectionBox: SelectionBox | null = null;
+  public selectionBox: SelectionBox | null = null;
   private componentPlacer: ComponentPlacer | null = null;
+  public selection: Selection | null = null;
+  public connectingWire: ConnectingWire | null = null;
 
   public board = new Board();
   public componentRepo = ComponentRepo.withDefaults();
 
+  public keysPressed = new Set<string>();
+
   render(canvas: HTMLCanvasElement) {
     const r = new Renderer(canvas, this.offset);
 
     r.clear();
     r.drawGrid();
-    this.board.render(r);
+    this.board.render(r, this.selection);
     this.selectionBox?.render(r);
     this.componentPlacer?.render(r);
+    this.connectingWire?.render(r);
   }
 
   renderIfNeeded(canvas: HTMLCanvasElement) {
@@ -32,24 +39,27 @@ export class Cx {
     }
   }
 
-  setRenderNeeded() {
-    this.renderNeeded = true;
-  }
-
   mouseDown(pos: V2) {
     this.state.onMouseDown?.(pos);
+    this.renderNeeded = true;
   }
   mouseUp(pos: V2) {
     this.state.onMouseUp?.(pos);
+    this.renderNeeded = true;
   }
   mouseMove(deltaPos: V2, pos: V2) {
     this.state.onMouseMove?.(deltaPos, pos);
+    this.renderNeeded = true;
   }
   keyDown(key: string) {
+    this.keysPressed.add(key);
     this.state.onKeyDown?.(key);
+    this.renderNeeded = true;
   }
   keyUp(key: string) {
+    this.keysPressed.delete(key);
     this.state.onKeyUp?.(key);
+    this.renderNeeded = true;
   }
   selectTool(tool: Tool) {
     switch (tool) {
@@ -67,6 +77,9 @@ export class Cx {
         this.transitionTo(new states.Normal(this));
     }
   }
+  selectedTool(): Tool {
+    return this.state.selectedTool?.() || "select";
+  }
 
   addUpdateAction(action: () => void): object {
     this.updateActions.push(action);
@@ -82,6 +95,7 @@ export class Cx {
   transitionTo(newState: states.State) {
     this.state.leaveState?.();
     this.state = newState;
+    console.log(`Entering state ${newState.constructor.name}`);
     this.state.enterState?.();
     this.notifyListeners();
   }
@@ -95,41 +109,19 @@ export class Cx {
   moveOffset(deltaPos: V2) {
     this.offset.x += deltaPos.x;
     this.offset.y += deltaPos.y;
-    this.renderNeeded = true;
-  }
-
-  addSelectionRect(pos: V2) {
-    this.selectionBox = new SelectionBox(pos, v2(0, 0));
-    this.renderNeeded = true;
-  }
-
-  removeSelectionRect() {
-    this.selectionBox = null;
-    this.renderNeeded = true;
-  }
-
-  moveSelectionRect(deltaPos: V2) {
-    if (this.selectionBox) {
-      this.selectionBox.size.x += deltaPos.x;
-      this.selectionBox.size.y += deltaPos.y;
-      this.renderNeeded = true;
-    }
   }
 
   addComponentPlacer(pos: V2, size: V2) {
     this.componentPlacer = new ComponentPlacer(pos, size);
-    this.renderNeeded = true;
   }
 
   removeComponentPlacer() {
     this.componentPlacer = null;
-    this.renderNeeded = true;
   }
 
   setComponentPlacerPos(pos: V2) {
     if (this.componentPlacer) {
       this.componentPlacer.pos = pos;
-      this.renderNeeded = true;
     }
   }
 
@@ -141,14 +133,27 @@ export class Cx {
 }
 
 export class SelectionBox {
-  constructor(
+  public size = v2(0, 0);
-    public pos: V2,
+
-    public size: V2,
+  constructor(public pos: V2) {}
-  ) {}
 
   render(r: Renderer) {
     r.drawSelectionBox(this.pos, this.size);
   }
+
+  move(deltaPos: V2) {
+    this.size = this.size.add(deltaPos);
+  }
+
+  normalized(): { pos: V2; size: V2 } {
+    const normalizedAxis = (p: number, s: number): [number, number] =>
+      s >= 0 ? [p, s] : [p + s, -s];
+
+    const [x, w] = normalizedAxis(this.pos.x, this.size.x);
+    const [y, h] = normalizedAxis(this.pos.y, this.size.y);
+
+    return { pos: v2(x, y), size: v2(w, h) };
+  }
 }
 
 export class ComponentPlacer {
@@ -162,4 +167,62 @@ export class ComponentPlacer {
   }
 }
 
-export type Tool = string;
+export class Selection {
+  selectedComponents = new Set<PlacedComponent>();
+
+  addComponent(comp: PlacedComponent) {
+    this.selectedComponents.add(comp);
+  }
+
+  toggleComponent(comp: PlacedComponent) {
+    if (this.selectedComponents.has(comp)) {
+      this.selectedComponents.delete(comp);
+    } else {
+      this.selectedComponents.add(comp);
+    }
+  }
+
+  isComponentSelected(comp: PlacedComponent) {
+    return this.selectedComponents.has(comp);
+  }
+}
+
+export class ConnectingWire {
+  constructor(
+    public kind: ConnectingWireKind,
+    public pos: V2,
+  ) {}
+
+  render(r: Renderer) {
+    switch (this.kind.tag) {
+      case "InputPin":
+      case "OutputPin":
+    }
+    r.drawConnectingWire(this.beginPos(), this.pos);
+  }
+
+  move(pos: V2) {
+    this.pos = pos;
+  }
+
+  private beginPos(): V2 {
+    switch (this.kind.tag) {
+      case "InputPin":
+        return v2(
+          this.kind.comp.pos.x,
+          this.kind.comp.pos.y +
+            this.kind.comp.kind.inputPinIter()[this.kind.i].pinOffset,
+        );
+      case "OutputPin":
+        return v2(
+          this.kind.comp.pos.x + this.kind.comp.kind.size.x,
+          this.kind.comp.pos.y +
+            this.kind.comp.kind.outputPinIter()[this.kind.i].pinOffset,
+        );
+    }
+  }
+}
+
+export type ConnectingWireKind =
+  | { tag: "InputPin"; comp: PlacedComponent; i: number }
+  | { tag: "OutputPin"; comp: PlacedComponent; i: number };

editor/src/editor/Renderer.ts

@@ -1,4 +1,4 @@
-import type { Component } from "./Board";
+import type { ComponentKind } from "./Board";
 import { v2, type V2 } from "./V2";
 
 export class Renderer {
@@ -57,23 +57,10 @@ export class Renderer {
     c.strokeRect(x, y, w, h);
   }
 
-  drawComponent(
+  drawComponentBody(pos: V2, kind: ComponentKind) {
-    comp: Component,
-    hoveredOverInput: [Component, number] | null,
-    hoveredOverOutput: [Component, number] | null,
-  ) {
     const { c, offset } = this;
-    const {
+    const { x, y } = pos.add(offset);
-      def: {
+    const { x: w, y: h } = kind.size;
-        size: { x: w, y: h },
-        label,
-        inputs,
-        outputs,
-      },
-      pos,
-    } = comp;
-
-    const [x, y] = [pos.x + offset.x, pos.y + offset.y];
 
     c.fillStyle = `#6abbde`;
     c.fillRect(x, y, w, h);
@@ -83,52 +70,92 @@ export class Renderer {
 
     c.fillStyle = `#333333`;
     c.font = "bold 16px monospace";
-    const textMetrix = c.measureText(label);
+    const textMetrix = c.measureText(kind.label);
     c.fillText(
-      label,
+      kind.label,
       x + w / 2 - textMetrix.width / 2,
       y + 13 + h / 2 - 16 / 2,
     );
-
-    {
-      const pinSpace = h / (inputs.length + 1);
-      for (let i = 0; i < inputs.length; ++i) {
-        if (inputs[i] !== null) {
-          throw new Error("pin text not implemented");
   }
-        c.fillStyle = `#333333`;
+  drawComponentBodySelected(pos: V2, kind: ComponentKind) {
-        c.beginPath();
+    const { c, offset } = this;
-        c.arc(x, y + (i + 1) * pinSpace, 4, 0, Math.PI * 2);
+    const { x, y } = pos.add(offset);
-        c.fill();
+    const { x: w, y: h } = kind.size;
 
-        if (hoveredOverInput?.[0] === comp && hoveredOverInput[1] === i) {
+    c.fillStyle = `#6abbde`;
-          c.strokeStyle = `#bbbbbb`;
+    c.fillRect(x, y, w, h);
+    c.strokeStyle = `#ff8800`;
     c.lineWidth = 2;
-          c.beginPath();
+    c.strokeRect(x, y, w, h);
-          c.arc(x, y + (i + 1) * pinSpace, 5, 0, Math.PI * 2);
+
-          c.stroke();
+    c.fillStyle = `#333333`;
-        }
+    c.font = "bold 16px monospace";
-      }
+    const textMetrix = c.measureText(kind.label);
-    }
+    c.fillText(
-    {
+      kind.label,
-      const pinSpace = h / (outputs.length + 1);
+      x + w / 2 - textMetrix.width / 2,
-      for (let i = 0; i < outputs.length; ++i) {
+      y + 13 + h / 2 - 16 / 2,
-        if (outputs[i] !== null) {
+    );
-          throw new Error("pin text not implemented");
   }
+
+  drawComponentInputPin(pos: V2, pinOffset: number) {
+    const { c, offset } = this;
+    const { x, y } = pos.add(offset);
+
     c.fillStyle = `#333333`;
     c.beginPath();
-        c.arc(x + w, y + (i + 1) * pinSpace, 4, 0, Math.PI * 2);
+    c.arc(x, y + pinOffset, 4, 0, Math.PI * 2);
     c.fill();
+  }
+
+  drawComponentInputPinHover(pos: V2, pinOffset: number) {
+    const { c, offset } = this;
+    const { x, y } = pos.add(offset);
 
-        if (hoveredOverOutput?.[0] === comp && hoveredOverOutput[1] === i) {
     c.strokeStyle = `#eee`;
     c.lineWidth = 2;
     c.beginPath();
-          c.arc(x + w, y + (i + 1) * pinSpace, 5, 0, Math.PI * 2);
+    c.arc(x, y + pinOffset, 5, 0, Math.PI * 2);
+    c.stroke();
+  }
+
+  drawComponentOutputPin(pos: V2, kind: ComponentKind, pinOffset: number) {
+    const { c, offset } = this;
+    const {
+      size: { x: w },
+    } = kind;
+    const { x, y } = pos.add(offset);
+
+    c.fillStyle = `#333333`;
+    c.beginPath();
+    c.arc(x + w, y + pinOffset, 4, 0, Math.PI * 2);
+    c.fill();
+  }
+
+  drawComponentOutputPinHover(pos: V2, kind: ComponentKind, pinOffset: number) {
+    const { c, offset } = this;
+    const {
+      size: { x: w },
+    } = kind;
+    const { x, y } = pos.add(offset);
+
+    c.strokeStyle = `#eee`;
+    c.lineWidth = 2;
+    c.beginPath();
+    c.arc(x + w, y + pinOffset, 5, 0, Math.PI * 2);
+    c.stroke();
+  }
+
+  drawConnectingWire(begin: V2, end: V2) {
+    const { c, offset } = this;
+    const { x: x0, y: y0 } = begin.add(offset);
+    const { x: x1, y: y1 } = end.add(offset);
+
+    c.strokeStyle = `#333333`;
+    c.lineWidth = 3;
+    c.beginPath();
+    c.moveTo(x0, y0);
+    c.lineTo(x1, y1);
     c.stroke();
   }
 }
-    }
-  }
-}

editor/src/editor/states.ts

@@ -1,5 +1,6 @@
-import type { ComponentDef } from "./Board";
+import { type ComponentKind } from "./Board";
-import type { Cx, Tool } from "./Cx";
+import { ConnectingWire, Selection } from "./Cx";
+import { SelectionBox, type Cx, type Tool } from "./Cx";
 import { v2, type V2 } from "./V2";
 
 export interface State {
@@ -20,21 +21,45 @@ export class Normal implements State {
     if (
       this.cx.board.handleMouseClick(
         pos.sub(this.cx.offset),
-        (comp, i) => {},
+        (comp, i) => {
-        (comp, i) => {},
+          console.log({ comp, i });
-        (comp) => {},
+          this.cx.connectingWire = new ConnectingWire(
+            {
+              tag: "InputPin",
+              comp,
+              i,
+            },
+            pos,
+          );
+          this.cx.transitionTo(new Wiring(this.cx));
+        },
+        (comp, i) => {
+          this.cx.connectingWire = new ConnectingWire(
+            {
+              tag: "OutputPin",
+              comp,
+              i,
+            },
+            pos,
+          );
+          this.cx.transitionTo(new Wiring(this.cx));
+        },
+        (comp) => {
+          this.cx.selection = new Selection();
+          this.cx.selection.addComponent(comp);
+          this.cx.transitionTo(new Selecting(this.cx));
+        },
       ) === "handled"
     ) {
       return;
     } else {
-      this.cx.addSelectionRect(pos);
+      this.cx.selectionBox = new SelectionBox(pos);
       this.cx.transitionTo(new SelectingBox(this.cx));
     }
   }
 
   onMouseMove(_deltaPos: V2, pos: V2): void {
     this.cx.board.updateMouseHover(pos.sub(this.cx.offset));
-    this.cx.setRenderNeeded();
   }
 
   onKeyDown(key: string): void {
@@ -88,7 +113,7 @@ export class Panning implements State {
 }
 
 export class Placing implements State {
-  private compDef: ComponentDef;
+  private compDef: ComponentKind;
 
   constructor(
     private cx: Cx,
@@ -131,21 +156,88 @@ export class Placing implements State {
 
 export class Selecting implements State {
   constructor(private cx: Cx) {}
+
+  onMouseDown(pos: V2): void {
+    if (
+      this.cx.board.handleMouseClick(
+        pos.sub(this.cx.offset),
+        (_comp, _i) => {},
+        (_comp, _i) => {},
+        (comp) => {
+          if (this.cx.keysPressed.has("Control")) {
+            this.cx.selection?.toggleComponent(comp);
+          } else {
+            this.cx.selection = new Selection();
+            this.cx.selection.addComponent(comp);
+          }
+        },
+      ) === "handled"
+    ) {
+      return;
+    } else {
+      if (this.cx.keysPressed.has("Control")) {
+        this.cx.selectionBox = new SelectionBox(pos);
+        this.cx.transitionTo(new SelectingBox(this.cx));
+      } else {
+        this.cx.selection = null;
+        this.cx.transitionTo(new Normal(this.cx));
+      }
+    }
+  }
 }
 
 export class SelectingBox implements State {
   constructor(private cx: Cx) {}
 
   onMouseUp(_pos: V2): void {
-    this.cx.removeSelectionRect();
+    if (!this.cx.selectionBox) {
+      throw new Error("expected selectionBox to active");
+    }
+    const { pos, size } = this.cx.selectionBox.normalized();
+    const selected = this.cx.board.componentsInRect(
+      pos.sub(this.cx.offset),
+      size,
+    );
+    if (selected.length > 0) {
+      this.cx.selection ??= new Selection();
+    }
+    for (const comp of selected) {
+      this.cx.selection?.addComponent(comp);
+    }
+    if (this.cx.selection) {
+      this.cx.selectionBox = null;
+      this.cx.transitionTo(new Selecting(this.cx));
+    } else {
+      this.cx.selectionBox = null;
       this.cx.transitionTo(new Normal(this.cx));
     }
+  }
 
   onMouseMove(deltaPos: V2): void {
-    this.cx.moveSelectionRect(deltaPos);
+    this.cx.selectionBox?.move(deltaPos);
   }
 
   selectedTool(): Tool | null {
     return "select";
   }
 }
+
+export class Wiring implements State {
+  constructor(private cx: Cx) {}
+
+  onMouseMove(_deltaPos: V2, pos: V2): void {
+    if (!this.cx.connectingWire) {
+      throw new Error("expected connectingWire to be active");
+    }
+    this.cx.connectingWire.move(pos);
+    this.cx.board.updateMouseHover(pos.sub(this.cx.offset));
+  }
+
+  onKeyDown(key: string): void {
+    if (key === "Escape") {
+      this.cx.transitionTo(new Normal(this.cx));
+      this.cx.connectingWire = null;
+      return;
+    }
+  }
+}