Add discussions

Discussions are served from GitHub's older server-rendered HTML, with no
embeddedData JSON to read, so the scraper walks the DOM the way the pull
request and wiki code does. A discussion's timeline opens with its own
post and continues with its comments, each carrying its replies nested
inside it, which is where the recursion in _discussionComment.eta comes
from. Categories, upvotes, and the answer a Q&A discussion is marked with
all come along.

Only what GitHub renders up front is shown: neither the next page of
discussions nor the replies it hides behind a "Show N previous replies"
button are fetched, so a comment says how many replies it is missing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/app.ts b/src/app.ts
index 0b9a7e6..ec3680b 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -5,6 +5,8 @@ import { buildCommit } from "./build.generated.ts";
 import {
   getGitHubBlob,
   getGitHubCommits,
+  getGitHubDiscussion,
+  getGitHubDiscussions,
   getGitHubIssues,
   getGitHubSidebar,
   getGitHubLatestCommit,
@@ -218,6 +220,28 @@ export function createApp(eta: Eta) {
     return c.render("pulls.eta", await getGitHubPulls(owner, repo, { q }));
   });
 
+  app.get("/:owner/:repo/discussions", async (c) => {
+    const { owner, repo } = c.req.param();
+    const q = c.req.query("discussions_q");
+    return c.render("discussions.eta", await getGitHubDiscussions(owner, repo, { q }));
+  });
+
+  app.get("/:owner/:repo/discussions/categories/:category", async (c) => {
+    const { owner, repo, category } = c.req.param();
+    const q = c.req.query("discussions_q");
+    return c.render("discussions.eta", await getGitHubDiscussions(owner, repo, { q, category }));
+  });
+
+  // GitHub puts its own actions (new, categories, ...) where a number goes, so
+  // anything that isn't one is not a discussion of ours to render.
+  app.get("/:owner/:repo/discussions/:number", async (c) => {
+    const { owner, repo, number } = c.req.param();
+    if (!/^\d+$/.test(number)) {
+      return redirectToGitHub(c);
+    }
+    return c.render("discussion.eta", await getGitHubDiscussion(owner, repo, Number(number)));
+  });
+
   app.get("/:owner/:repo/search", async (c) => {
     const { owner, repo } = c.req.param();
     const q = c.req.query("q") ?? "";
@@ -227,6 +251,8 @@ export function createApp(eta: Eta) {
       return c.redirect(`/${owner}/${repo}/issues?q=${encodeURIComponent(q)}`);
     } else if (type === "pullrequests") {
       return c.redirect(`/${owner}/${repo}/pulls?q=${encodeURIComponent(q)}`);
+    } else if (type === "discussions") {
+      return c.redirect(`/${owner}/${repo}/discussions?discussions_q=${encodeURIComponent(q)}`);
     }
 
     // Redirect unhandled search types (like code, which requires sign in anyway).