Apply schema to model (#1)

This commit enhances the editor to support schema management and
improved text insertion logic.

It also introduces new command structure for text operations. and it adds
methods for node handling, utility functions, and a new schema for plain
text. Implement comprehensive unit tests to ensure reliability.

src/commands/commands.ts

@@ -0,0 +1,48 @@
+import { Model } from '../model/model';
+import { Range } from '../model/types';
+import { Operation } from '../model/operations';
+
+export type Command = {
+  ops: Array<Operation>;
+};
+
+export function insertText(range: Range, text: string): Command {
+  return {
+    ops: [
+      {
+        type: 'edit',
+        range,
+        value: [{ type: 'text', text }],
+      },
+    ],
+  };
+}
+
+export function splitBlock(range: Range): Command {
+  // TODO(hackerwins): Implement this according to the schema.
+  return {
+    ops: [
+      {
+        type: 'edit',
+        range,
+        value: [{ type: 'p' }],
+      },
+    ],
+  };
+}
+
+/**
+ * `execute` executes the command on the model and returns inverse command.
+ */
+export function execute(model: Model, command: Command): Command {
+  const ops = [];
+
+  for (const op of command.ops) {
+    const inverse = model.apply(op);
+    ops.push(inverse);
+  }
+
+  return {
+    ops: ops,
+  };
+}

src/editor.ts

@@ -4,13 +4,15 @@ import { Observable, Unsubscribe } from './utils/observable';
 
 import { View as View } from './view/view';
 import { Model } from './model/model';
-import { Command, execute } from './commands';
+import { Command, execute, insertText } from './commands/commands';
+import { SchemaSpec, BasicSchema } from './model/schema';
 
 /**
  * `EditorOptions` is an object that contains the initial value of the editor
  *  and the plugins that should be initialized.
  */
 type EditorOptions = {
+  schema: SchemaSpec;
   initialValue?: string;
   plugins?: Array<Module>;
 };
@@ -28,7 +30,10 @@ export class Editor extends Observable<Array<Command>> implements Module {
 
   private plugins: Array<Module>;
 
-  static create(container: HTMLDivElement, opts: EditorOptions = {}) {
+  static create(
+    container: HTMLDivElement,
+    opts: EditorOptions = { schema: BasicSchema },
+  ) {
     const editor = new Editor(container, opts);
     editor.initialize();
     return editor;
@@ -38,7 +43,7 @@ export class Editor extends Observable<Array<Command>> implements Module {
     super();
 
     this.view = View.create(container);
-    this.model = Model.create(opts.initialValue || '');
+    this.model = Model.create(opts.schema, opts.initialValue || '');
     this.history = new History<Command>((command) =>
       execute(this.model, command),
     );
@@ -50,7 +55,7 @@ export class Editor extends Observable<Array<Command>> implements Module {
 
   initialize() {
     // 01. Initialize the view with the model's content.
-    this.view.setValue(this.model.getValue());
+    this.view.setValue(this.model.toXML());
 
     // 02. Upstream: view creates commands and then the editor executes them.
     this.unsubscribes.push(
@@ -63,13 +68,14 @@ export class Editor extends Observable<Array<Command>> implements Module {
 
     // 03. Downstream: If the model changes, the view should be updated.
     this.unsubscribes.push(
-      this.model.subscribe((value) => {
+      this.model.subscribe(() => {
         // Prevent downstream updates if the view is the source of change.
         if (this.isUpstream) {
           return;
         }
 
-        this.view.setValue(value);
+        // TODO(hackerwins): We need to optimize this part.
+        this.view.setValue(this.model.toXML());
       }),
     );
 
@@ -126,11 +132,11 @@ export class Editor extends Observable<Array<Command>> implements Module {
    * TODO(hackerwins): Find a better way to provide APIs.
    */
   insertText(text: string) {
-    this.execute({
-      t: 'e',
-      s: this.model.getValue().length,
-      e: this.model.getValue().length,
-      v: text,
-    });
+    let range = this.view.getSelection();
+    if (!range) {
+      range = this.model.getContentEndRange();
+    }
+
+    this.execute(insertText(range, text));
   }
 }

src/main.ts

@@ -6,7 +6,12 @@ import { Devtools } from './plugins/devtools';
 const editor = Editor.create(
   document.querySelector<HTMLDivElement>('#editor')!,
   {
-    initialValue: 'Hello,',
+    initialValue: '<p>Hello,</p>',
+    schema: {
+      root: { children: 'p*' },
+      p: { children: 'text*' },
+      text: {},
+    },
     plugins: [
       Toolbar.create(document.querySelector<HTMLDivElement>('#toolbar')!, {
         buttons: ['destroy', 'undo', 'redo'],

src/model/model.ts

@@ -1,33 +1,160 @@
 import { Observable } from '../utils/observable';
+import { Node, Text, Element, Range, NodePos } from './types';
+import { Schema, SchemaSpec } from './schema';
+import { Operation } from './operations';
+import {
+  insertAfter,
+  insertBefore,
+  lengthOf,
+  pathOf,
+  removeNode,
+  splitText,
+  toXML,
+} from './nodes';
+import { firstOf, lastOf } from '../utils/array';
+import { isLeftMost, toNodePos, nodesBetween } from './nodepos';
+import { isCollapsed } from './range';
 
-// TODO(hackerwins): Build a tree-based model with schema validation.
-export class Model extends Observable<string> {
-  private value: string;
+export class Model extends Observable<Array<Operation>> {
+  private schema: Schema;
+  private root: Element;
 
-  static create(initialValue: string): Model {
-    return new Model(initialValue);
+  static create(spec: SchemaSpec, initialValue: string): Model {
+    const schema = new Schema(spec);
+    const value = schema.fromXML(initialValue);
+    return new Model(schema, value);
   }
 
-  constructor(value: string) {
+  constructor(schema: Schema, value: Node) {
     super();
-    this.value = value;
+    this.schema = schema;
+    this.root = value;
   }
 
-  setValue(value: string): void {
-    this.value = value;
-    this.notify(this.value);
+  createText(value: string): Text {
+    return this.schema.create('text', value) as Text;
   }
 
-  getValue(from?: number, to?: number): string {
-    if (from !== undefined && to !== undefined) {
-      return this.value.slice(from, to);
+  toXML(): string {
+    return toXML(this.root);
+  }
+
+  apply(op: Operation): Operation {
+    let inverse: Operation;
+    switch (op.type) {
+      case 'edit':
+        inverse = this.edit(op.range, op.value);
+        this.notify([op]);
+        return inverse;
+      case 'move':
+        inverse = this.move(/*op.source, op.target*/);
+        this.notify([op]);
+        return inverse;
+      default:
+        throw new Error(`invalid operation type: ${op}`);
+    }
+  }
+
+  edit(range: Range, values: Array<Node>): Operation {
+    // NOTE(hackerwins): To keep the node of the position, we need to split the
+    // text node at the end of the range.
+    const end = this.nodePosOf(range.e);
+    const start = isCollapsed(range) ? end : this.nodePosOf(range.s);
+
+    const nodesToRemove: Array<Node> = [];
+    for (const [node, type] of nodesBetween(this.root, start, end)) {
+      if (type === 'open') {
+        continue;
+      }
+
+      nodesToRemove.push(node);
+    }
+
+    for (const node of nodesToRemove) {
+      removeNode(node);
+    }
+
+    const hasValues = values.length > 0;
+    if (hasValues) {
+      if (isLeftMost(start)) {
+        insertBefore(start.node, ...values);
+      } else {
+        insertAfter(start.node, ...values);
+      }
+    }
+
+    return {
+      type: 'edit',
+      range: hasValues ? this.rangeOf(values) : { s: range.s, e: range.s },
+      value: nodesToRemove,
+    };
+  }
+
+  /**
+   * `rangeOf` returns the range of the given nodes in the model.
+   */
+  rangeOf(values: Array<Node>): Range {
+    // TODO(hackerwins): This is a naive implementation that assumes the first
+    // and last nodes are always text nodes. We need to handle the case where
+    // the first and last nodes are elements.
+    const start = pathOf(firstOf(values)!, this.root);
+    start.push(0);
+
+    const end = pathOf(lastOf(values)!, this.root);
+    end.push(lengthOf(lastOf(values)!));
+
+    return { s: start, e: end };
+  }
+
+  /**
+   * `nodePosOf` returns the node position of the given path.
+   */
+  nodePosOf(path: Array<number>, withSplitText: boolean = true): NodePos {
+    const pos = toNodePos(path, this.root);
+    if (!withSplitText) {
+      return pos;
+    }
+
+    const newNode = splitText(pos);
+    if (!newNode) {
+      return pos;
+    }
+
+    return {
+      node: newNode,
+      offset: 0,
+    };
+  }
+
+  /**
+   * `getContentEndRange` returns the range of the end of the content in the
+   *  model.
+   */
+  getContentEndRange(): Range {
+    const path = [];
+
+    let node = this.root;
+    while (node) {
+      if (node.type === 'text') {
+        const text = node as Text;
+        path.push(text.text.length);
+        break;
+      }
+
+      const elem = node as Element;
+      const children = elem.children || [];
+      if (children.length === 0) {
+        break;
+      }
+
+      path.push(children.length - 1);
+      node = lastOf(children)!;
     }
 
-    return this.value;
+    return { s: path, e: path };
   }
 
-  edit(start: number, end: number, text: string): void {
-    this.value = this.value.slice(0, start) + text + this.value.slice(end);
-    this.notify(this.value);
+  move(/*source: Range, target: Range*/): Operation {
+    throw new Error('Method not implemented.');
   }
 }