From a984c69e3cca4bcf822989bb78a8befe2397e487 Mon Sep 17 00:00:00 2001
From: Josh Kingsley <josh@joshkingsley.me>
Date: Sun, 26 Oct 2025 18:31:23 +0200
Subject: feat(web): draw selection

---
 web/src/selection.ts | 43 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 5 deletions(-)

(limited to 'web/src/selection.ts')

diff --git a/web/src/selection.ts b/web/src/selection.ts
index 88d394b..3d18417 100644
--- a/web/src/selection.ts
+++ b/web/src/selection.ts
@@ -1,4 +1,4 @@
-import { CellRef } from "./types";
+import { CellRef, cellRefEquals } from "./types";
 
 export abstract class Selection {
   readonly gridId: string;
@@ -8,12 +8,45 @@ export abstract class Selection {
     this.gridId = gridId;
     this.activeCellRef = activeCellRef;
   }
+
+  abstract extend(cellRef: CellRef): Selection;
+}
+
+export class ActiveCellSelection extends Selection {
+  extend(cellRef: CellRef): Selection {
+    if (cellRefEquals(cellRef, this.activeCellRef)) {
+      return this;
+    }
+
+    return new RangeSelection(this.gridId, this.activeCellRef, [
+      this.activeCellRef,
+      cellRef,
+    ]);
+  }
 }
 
-export class ActiveCellSelection extends Selection {}
+export type CellRange = [CellRef, CellRef];
 
-export class RangeSelection extends Selection {}
+export class RangeSelection extends Selection {
+  #range: CellRange;
 
-export class AllSelection extends Selection {}
+  get range() {
+    return this.#range;
+  }
 
-export class PendingSelection extends Selection {}
+  constructor(gridId: string, activeCellRef: CellRef, range: CellRange) {
+    super(gridId, activeCellRef);
+    this.#range = range;
+  }
+
+  extend(cellRef: CellRef): Selection {
+    if (cellRefEquals(cellRef, this.activeCellRef)) {
+      return new ActiveCellSelection(this.gridId, cellRef);
+    }
+
+    return new RangeSelection(this.gridId, this.activeCellRef, [
+      this.#range[0],
+      cellRef,
+    ]);
+  }
+}
-- 
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