Recover presenter work after failures

Author: itsjling

package.json

@@ -33,6 +33,7 @@
     "scripts/doctor.mjs",
     "scripts/generate-summaries.mjs",
     "scripts/present.mjs",
+    "scripts/presenter-runtime.mjs",
     "scripts/serve-built.mjs",
     "scripts/summary-path.mjs"
   ],

scripts/present.mjs

@@ -1,9 +1,8 @@
 #!/usr/bin/env node
 
-import { spawn, spawnSync } from 'node:child_process';
+import { spawn } from 'node:child_process';
 import { createHash } from 'node:crypto';
 import {
-  existsSync,
   mkdtempSync,
   readFileSync,
   rmSync,
@@ -19,6 +18,7 @@ import {
   selectCodingAgent,
 } from './coding-agents.mjs';
 import { doctorReport } from './doctor.mjs';
+import { ensureBuiltAssets, openBrowser } from './presenter-runtime.mjs';
 
 const root = resolve(dirname(fileURLToPath(import.meta.url)), '..');
 const callerDirectory = process.cwd();
@@ -100,18 +100,11 @@ if (agentEnabled) {
   agentArgs.push('--snapshot', outputPath);
 }
 
-const builtPage = resolve(root, 'dist/index.html');
-if (!existsSync(builtPage)) {
-  const result = spawnSync(
-    process.platform === 'win32' ? 'npm.cmd' : 'npm',
-    ['run', 'build'],
-    { cwd: root, stdio: 'inherit' },
-  );
-  if (result.error) {
-    console.error(`Could not build the local page: ${result.error.message}`);
-    process.exit(1);
-  }
-  if (result.status !== 0) process.exit(result.status || 1);
+try {
+  ensureBuiltAssets({ root });
+} catch (error) {
+  console.error(error.message);
+  process.exit(1);
 }
 
 const feed = spawn(
@@ -127,37 +120,11 @@ let site;
 let agent;
 let agentTimer;
 let agentFingerprint;
+let failedAgentFingerprint;
 let queuedFingerprint;
 let browserOpened = false;
 let browserOpenTimer;
 
-function openBrowser(url) {
-  let command;
-  let args;
-  if (process.env.BROWSER) {
-    command = process.env.BROWSER;
-    args = [url];
-  } else if (process.platform === 'darwin') {
-    command = 'open';
-    args = [url];
-  } else if (process.platform === 'win32') {
-    command = 'cmd.exe';
-    args = ['/d', '/s', '/c', 'start', '', url];
-  } else {
-    command = 'xdg-open';
-    args = [url];
-  }
-
-  const opener = spawn(command, args, {
-    detached: true,
-    stdio: 'ignore',
-  });
-  opener.once('error', (error) => {
-    console.error(`Could not open the browser: ${error.message}`);
-  });
-  opener.unref();
-}
-
 function startSite() {
   if (closing || site) return;
   const child = spawn(
@@ -196,7 +163,10 @@ function startSite() {
         browserOpenTimer = setTimeout(() => {
           browserOpenTimer = undefined;
           browserOpened = true;
-          openBrowser(match[1]);
+          openBrowser(match[1], {
+            onError: (error) =>
+              console.error(`Could not open the browser: ${error.message}`),
+          });
         }, 750);
       }
     });
@@ -287,11 +257,14 @@ function runAgent(fingerprint) {
     settled = true;
     const finishedFingerprint = agentFingerprint;
     if (agent === child) agent = undefined;
-    agentFingerprint = finishedFingerprint;
-    if (!closing && (error || code || signal)) {
+    agentFingerprint = undefined;
+    const superseded =
+      queuedFingerprint && queuedFingerprint !== finishedFingerprint;
+    if (!closing && (error || code || signal) && !superseded) {
+      failedAgentFingerprint = finishedFingerprint;
       if (error) console.error(error.message);
       console.error(
-        'The coding agent could not write notes. The diff page will stay open.',
+        'The coding agent could not write notes. It will retry after the diff changes or Diffsplain restarts.',
       );
     }
     const latest = queuedFingerprint || snapshotFingerprint();
@@ -311,10 +284,15 @@ function scheduleAgent(fingerprint) {
     state?.hasCurrentAgentNotes &&
     selectedFingerprint === state.fingerprint
   ) {
-    agentFingerprint = selectedFingerprint;
     return;
   }
-  if (!selectedFingerprint || selectedFingerprint === agentFingerprint) return;
+  if (
+    !selectedFingerprint ||
+    selectedFingerprint === agentFingerprint ||
+    selectedFingerprint === failedAgentFingerprint
+  ) {
+    return;
+  }
   if (agent) {
     if (selectedFingerprint !== agentFingerprint) {
       queuedFingerprint = selectedFingerprint;

scripts/presenter-runtime.mjs

@@ -0,0 +1,71 @@
+import { spawn, spawnSync } from 'node:child_process';
+import { existsSync } from 'node:fs';
+import { join } from 'node:path';
+
+export function browserCommand({ url, browser, platform = process.platform }) {
+  if (browser) return { command: browser, args: [url] };
+  if (platform === 'darwin') return { command: 'open', args: [url] };
+  if (platform === 'win32') {
+    return { command: 'cmd.exe', args: ['/d', '/s', '/c', 'start', '', url] };
+  }
+  return { command: 'xdg-open', args: [url] };
+}
+
+export function openBrowser(
+  url,
+  {
+    browser = process.env.BROWSER,
+    platform = process.platform,
+    spawnProcess = spawn,
+    onError = () => {},
+  } = {},
+) {
+  try {
+    const { command, args } = browserCommand({ url, browser, platform });
+    const opener = spawnProcess(command, args, { detached: true, stdio: 'ignore' });
+    opener.once('error', onError);
+    opener.unref();
+    return opener;
+  } catch (error) {
+    onError(error);
+    return undefined;
+  }
+}
+
+function builtAssetsReady({ root, exists = existsSync }) {
+  const dist = join(root, 'dist');
+  return exists(join(dist, 'index.html')) && exists(join(dist, 'assets'));
+}
+
+function npmCommand(platform) {
+  return platform === 'win32' ? 'npm.cmd' : 'npm';
+}
+
+function buildAssets(runtime) {
+  const result = runtime.run(npmCommand(runtime.platform), ['run', 'build'], {
+    cwd: runtime.root,
+    stdio: 'inherit',
+  });
+  if (result.error) {
+    throw new Error(`Could not build the local page: ${result.error.message}`);
+  }
+  if (result.status === 0) return;
+  const status = Number.isInteger(result.status) ? Number(result.status) : 1;
+  throw new Error(`Could not build the local page: npm run build exited with ${status}.`);
+}
+
+export function ensureBuiltAssets(options) {
+  const runtime = {
+    exists: existsSync,
+    run: spawnSync,
+    platform: process.platform,
+    ...options,
+  };
+  if (builtAssetsReady({ root: runtime.root, exists: runtime.exists })) return false;
+
+  buildAssets(runtime);
+  if (!builtAssetsReady({ root: runtime.root, exists: runtime.exists })) {
+    throw new Error('Could not build the local page: built assets are still missing.');
+  }
+  return true;
+}