2 files changed, 117 insertions, 101 deletions

diff --git a/web/src/doc/index.test.ts b/web/src/doc/index.test.ts
index 331d0a5..5f61398 100644
--- a/web/src/doc/index.test.ts
+++ b/web/src/doc/index.test.ts
@@ -1,15 +1,16 @@
-import { describe, expect, test } from "vitest";
-import Doc from ".";
-
-describe(Doc, () => {
-  describe(Doc.default, () => {
-    const doc = Doc.default();
-
-    test("produces valid grid data", () => {
-      expect(doc.grids.length).toBe(1);
-      expect(doc.grids[0].doc).toBe(doc);
-      expect(doc.grids[0].rows.length).toBe(4);
-      expect(doc.grids[0].rows[0].cells.length).toBe(16);
-    });
-  });
+import { expect, test } from "vitest";
+import { apply, defaultDoc, realizeGrids, subdivide } from ".";
+
+test(realizeGrids, () => {
+  const doc = defaultDoc();
+  const grids = realizeGrids(doc);
+
+  expect(grids.length).toBe(1);
+  expect(grids[0].rows.length).toBe(4);
+  expect(grids[0].rows[0].cells.length).toBe(16);
+
+  const doc2 = apply(doc, subdivide(grids[0].id, 0, 0, 3, 3));
+  const grids2 = realizeGrids(doc2);
+
+  expect(grids2[0].rows[0].cells.length).toBe(15);
 });
diff --git a/web/src/doc/index.ts b/web/src/doc/index.ts
index a58faa6..ae221f0 100644
--- a/web/src/doc/index.ts
+++ b/web/src/doc/index.ts
@@ -1,110 +1,125 @@
-export abstract class DocOp {
-  abstract key: string;
+import { Immutable, produce } from "immer";
+
+export type Doc = Immutable<{ ops: Op[] }>;
+
+export type Op = CreateGrid | Subdivide;
+
+export type CreateGrid = Immutable<{
+  type: "createGrid";
+  gridId: string;
+  rows: number;
+  baseCellsPerRow: number;
+}>;
+
+export function createGrid(): CreateGrid {
+  return {
+    type: "createGrid",
+    gridId: crypto.randomUUID(),
+    rows: 4,
+    baseCellsPerRow: 16,
+  };
 }
 
-export class CreateGridOp extends DocOp {
-  gridId: string = crypto.randomUUID();
-  rows = 4;
-  key = this.gridId;
-  baseCellsPerRow = 16;
+export type Subdivide = Immutable<{
+  type: "subdivide";
+  gridId: string;
+  rowIndex: number;
+  startCellIndex: number;
+  endCellIndex: number;
+  subdivisions: number;
+}>;
+
+export function subdivide(
+  gridId: string,
+  rowIndex: number,
+  startCellIndex: number,
+  endCellIndex: number,
+  subdivisions: number,
+): Subdivide {
+  return {
+    type: "subdivide",
+    gridId,
+    rowIndex,
+    startCellIndex,
+    endCellIndex,
+    subdivisions,
+  };
 }
 
-export default class Doc {
-  readonly ops: DocOp[];
-
-  readonly opsByKey: Map<string, readonly DocOp[]>;
-  readonly opsByType: Map<Function, readonly DocOp[]>;
-
-  constructor(ops: DocOp[]) {
-    this.ops = ops;
-
-    const opsByKey = new Map();
-    const opsByType = new Map();
-
-    for (const op of ops) {
-      const maybeKeyOps = opsByKey.get(op.key);
-
-      if (maybeKeyOps) maybeKeyOps.push(op);
-      else opsByKey.set(op.key, [op]);
+export function defaultDoc(): Doc {
+  const ops = [createGrid()];
+  return { ops };
+}
 
-      const maybeTypeOps = opsByType.get(op.constructor);
+export function apply(doc: Doc, ...ops: Op[]): Doc {
+  return produce(doc, (doc) => {
+    doc.ops.push(...ops);
+  });
+}
 
-      if (maybeTypeOps) maybeTypeOps.push(op);
-      else opsByType.set(op.constructor, [op]);
-    }
+export type DocIndex = Immutable<{
+  opsByType: Map<Op["type"], Op[]>;
+}>;
 
-    this.opsByKey = opsByKey;
-    this.opsByType = opsByType;
-  }
+export function indexDoc(doc: Doc): DocIndex {
+  const opsByType = new Map();
 
-  static default(): Doc {
-    return new Doc([new CreateGridOp()]);
+  for (const op of doc.ops) {
+    opsByType.set(op.type, [...(opsByType.get(op.type) ?? []), op]);
   }
 
-  get grids(): Grid[] {
-    const ops = this.opsByType.get(CreateGridOp) ?? [];
-    return ops.map((op) => new Grid(this, op as CreateGridOp));
-  }
+  return { opsByType };
 }
 
-export class Grid {
-  readonly doc: Doc;
-  readonly id: string;
-  readonly rows: readonly Row[];
+export function getOpsByType<T extends Op["type"]>(
+  index: DocIndex,
+  type: T,
+): Extract<Op, { type: T }>[] {
+  return (index.opsByType.get(type) ?? []) as Extract<Op, { type: T }>[];
+}
 
-  constructor(doc: Doc, createOp: CreateGridOp) {
-    this.doc = doc;
-    this.id = createOp.gridId;
+export type Grid = Immutable<{ id: string; rows: Row[] }>;
 
-    const rows: Row[] = [];
+export type Row = Immutable<{ index: number; cells: Cell[] }>;
 
-    for (let rowIndex = 0; rowIndex < createOp.rows; rowIndex++) {
-      rows.push(new Row(doc, this.id, rowIndex));
-    }
+export type Cell = Immutable<{}>;
 
-    this.rows = rows;
-  }
+export function realizeGrids(doc: Doc): Grid[] {
+  const index = indexDoc(doc);
+  const createGridOps = getOpsByType(index, "createGrid");
+  return createGridOps.map((op) => realizeGrid(doc, index, op));
 }
 
-export class Row {
-  readonly doc: Doc;
-  readonly gridId: string;
-  readonly index: number;
-  readonly cells: readonly Cell[];
-
-  constructor(doc: Doc, gridId: string, index: number) {
-    this.doc = doc;
-    this.gridId = gridId;
-    this.index = index;
-
-    const createGridOp = doc.opsByType
-      .get(CreateGridOp)
-      ?.find((op) => op.key === gridId)! as CreateGridOp;
-
-    const cells: Cell[] = [];
-
-    for (
-      let cellIndex = 0;
-      cellIndex < createGridOp.baseCellsPerRow;
-      cellIndex++
-    ) {
-      cells.push(new Cell(doc, gridId, index, cellIndex));
+function realizeGrid(doc: Doc, index: DocIndex, createOp: CreateGrid): Grid {
+  const rows = [];
+
+  for (let rowIndex = 0; rowIndex < createOp.rows; rowIndex++) {
+    let cells: Cell[] = [];
+
+    for (let cellIndex = 0; cellIndex < createOp.baseCellsPerRow; cellIndex++) {
+      cells.push({ index: cellIndex });
     }
 
-    this.cells = cells;
+    const subdivideOps = doc.ops.filter(
+      (op) =>
+        op.type === "subdivide" &&
+        op.gridId === createOp.gridId &&
+        op.rowIndex === rowIndex,
+    ) as Subdivide[];
+
+    subdivideOps.forEach((op) => {
+      cells = [
+        ...cells.slice(0, op.startCellIndex),
+        ...Array.from({ length: op.subdivisions }, () => ({})),
+        ...cells.slice(op.endCellIndex + 1),
+      ];
+    });
+
+    rows.push({ index: rowIndex, cells });
   }
-}
 
-export class Cell {
-  readonly doc: Doc;
-  readonly gridId: string;
-  readonly rowIndex: number;
-  readonly index: number;
-
-  constructor(doc: Doc, gridId: string, rowIndex: number, index: number) {
-    this.doc = doc;
-    this.gridId = gridId;
-    this.rowIndex = rowIndex;
-    this.index = index;
-  }
+  return {
+    id: createOp.gridId,
+    rows,
+  };
 }