Architecture decisions: files, diagram references, views and panels

- *.archify-decision files: id (unique, words), title, status, date,
  elements, diagrams, supersedes, and prose; parsed, merged and link-checked
  in the model index; diagnostics on the file
- diagrams point at decisions with decisions: [...] on the diagram, nodes
  and edges; stripped before Archify, unknown ids reported, completion,
  hover and go-to-definition for the ids and for elements/diagrams/
  supersedes in decision files
- Decisions panel on the main.archify page; Decisions rail panel under a
  diagram (hover lights up the node or connection); decisions on element
  cards and in the element dialog; decision view for the file, with a
  lost-model note outside a model
- Archify | New Decision… command and template; editor schemas; the three
  New Model examples carry decisions; docs, changelog, 0.8.0

src/views/decisionView.ts

@@ -0,0 +1,152 @@
+import path from 'node:path';
+import * as vscode from 'vscode';
+import { isDecisionFile, parseDecision } from '../model/decisions';
+import { isMainFile, isRegistryFile } from '../model/format';
+import { DecisionPanel, decisionPanelFromIndex, decisionPanelStandalone } from '../model/panel';
+import { ModelService } from '../model/service';
+import { readText } from '../util/files';
+import { log } from '../util/log';
+import { handleWebviewMessage, WebviewMessage } from '../webview/messages';
+import { decisionPage, makeNonce } from '../webview/page';
+import { DECISION_VIEW_TYPE, DIAGRAM_EDITOR_VIEW_TYPE, REGISTRY_VIEW_TYPE } from './viewTypes';
+
+export { DECISION_VIEW_TYPE };
+
+class DecisionDocument implements vscode.CustomDocument {
+  constructor(readonly uri: vscode.Uri) {}
+  dispose(): void {}
+}
+
+class DecisionView implements vscode.Disposable {
+  private seq = 0;
+  private timer: NodeJS.Timeout | undefined;
+  private last: string | undefined;
+  root: vscode.Uri | undefined;
+  private readonly disposables: vscode.Disposable[] = [];
+
+  constructor(
+    private readonly models: ModelService,
+    readonly panel: vscode.WebviewPanel,
+    readonly uri: vscode.Uri,
+  ) {
+    this.disposables.push(
+      panel.webview.onDidReceiveMessage((message: WebviewMessage) => {
+        if (message.type === 'openDiagram') return void this.openInModel(message.path, DIAGRAM_EDITOR_VIEW_TYPE);
+        if (message.type === 'openRegistry') return void this.openRegistryLine(message.file, message.line);
+        if (message.type === 'openDecision') return void this.openInModel(message.file, DECISION_VIEW_TYPE);
+        void handleWebviewMessage(message, this.uri, this.panel);
+      }),
+    );
+    void this.update();
+  }
+
+  private async openInModel(relativePath: string, viewType: string): Promise<void> {
+    if (!this.root) return;
+    const target = vscode.Uri.joinPath(this.root, ...relativePath.split('/'));
+    try {
+      await vscode.workspace.fs.stat(target);
+    } catch {
+      vscode.window.showWarningMessage(`Archify: ${relativePath} does not exist in this model.`);
+      return;
+    }
+    await vscode.commands.executeCommand('vscode.openWith', target, viewType, vscode.ViewColumn.Active);
+  }
+
+  private async openRegistryLine(file: string, line?: number): Promise<void> {
+    if (!this.root) return;
+    const target = vscode.Uri.joinPath(this.root, ...file.split('/'));
+    const column = this.panel.viewColumn === vscode.ViewColumn.One ? vscode.ViewColumn.Two : vscode.ViewColumn.One;
+    const at = Math.max(line ?? 0, 0);
+    await vscode.window.showTextDocument(target, { viewColumn: column, selection: new vscode.Range(at, 0, at, 0) });
+  }
+
+  scheduleUpdate(): void {
+    clearTimeout(this.timer);
+    this.timer = setTimeout(() => void this.update(), 300);
+  }
+
+  async update(): Promise<void> {
+    clearTimeout(this.timer);
+    const seq = ++this.seq;
+    let decision: DecisionPanel;
+    try {
+      this.root = await this.models.rootOf(this.uri);
+      if (this.root) {
+        const rel = path.relative(this.root.fsPath, this.uri.fsPath).split(path.sep).join('/');
+        decision = decisionPanelFromIndex(await this.models.index(this.root), rel);
+      } else {
+        const name = path.basename(this.uri.path);
+        decision = decisionPanelStandalone(name, parseDecision(await readText(this.uri), name));
+      }
+    } catch (error) {
+      log().warn(`Decision view failed for ${this.uri.fsPath}: ${error instanceof Error ? error.message : String(error)}`);
+      return;
+    }
+    if (seq !== this.seq) return;
+    const fingerprint = JSON.stringify(decision);
+    if (fingerprint === this.last) return;
+    this.last = fingerprint;
+    this.panel.webview.html = decisionPage({ cspSource: this.panel.webview.cspSource, nonce: makeNonce() }, decision);
+  }
+
+  dispose(): void {
+    clearTimeout(this.timer);
+    for (const d of this.disposables.splice(0)) d.dispose();
+  }
+}
+
+/** Read-only custom editor for .archify-decision files: the decision as a page, with its elements and diagrams. */
+export class DecisionViewProvider implements vscode.CustomReadonlyEditorProvider<DecisionDocument>, vscode.Disposable {
+  private readonly views = new Set<DecisionView>();
+  private active: DecisionView | undefined;
+  private readonly disposables: vscode.Disposable[];
+
+  constructor(private readonly models: ModelService) {
+    this.disposables = [
+      vscode.window.registerCustomEditorProvider(DECISION_VIEW_TYPE, this, {
+        webviewOptions: { retainContextWhenHidden: true, enableFindWidget: true },
+        supportsMultipleEditorsPerDocument: true,
+      }),
+      models.onDidChangeModel(({ root }) => {
+        for (const view of this.views) if (view.root?.toString() === root.toString()) view.scheduleUpdate();
+      }),
+      vscode.workspace.onDidChangeTextDocument((event) => {
+        if (!isDecisionFile(event.document.fileName) && !isRegistryFile(event.document.fileName) && !isMainFile(event.document.fileName)) return;
+        for (const view of this.views) if (!view.root && view.uri.toString() === event.document.uri.toString()) view.scheduleUpdate();
+      }),
+    ];
+  }
+
+  /** File shown in the focused decision view, if any. */
+  get activeUri(): vscode.Uri | undefined {
+    return this.active?.uri;
+  }
+
+  openCustomDocument(uri: vscode.Uri): DecisionDocument {
+    return new DecisionDocument(uri);
+  }
+
+  async resolveCustomEditor(document: DecisionDocument, panel: vscode.WebviewPanel): Promise<void> {
+    panel.webview.options = { enableScripts: true };
+    const view = new DecisionView(this.models, panel, document.uri);
+    this.views.add(view);
+    const onViewState = () => {
+      if (panel.active) this.active = view;
+      else if (this.active === view) this.active = undefined;
+      if (panel.active) void vscode.commands.executeCommand('setContext', 'archify.inModel', Boolean(view.root));
+    };
+    panel.onDidChangeViewState(onViewState);
+    onViewState();
+    panel.onDidDispose(() => {
+      this.views.delete(view);
+      if (this.active === view) this.active = undefined;
+      view.dispose();
+    });
+  }
+
+  dispose(): void {
+    for (const view of this.views) view.dispose();
+    this.views.clear();
+    for (const d of this.disposables.splice(0)) d.dispose();
+  }
+}