Inline comments (#10)

A finding about one line now lands on that line of the diff: the agent writes anchors as JSON, and the review posts them with the body in one call. Bad entries fail the run, and an anchor Gitea refuses falls back to posting the body alone.

Verified with deno fmt, lint and check.

Reviewed-on: #10
Co-authored-by: bot <temeddix@gmail.com>
Co-committed-by: bot <temeddix@gmail.com>

run.ts

@@ -64,12 +64,50 @@ async function postComment(body: string): Promise<void> {
 // picks up narration while a file's first line is written on purpose. That line
 // is the verdict, matched whole; anything unexpected only comments, never
 // approves. The mark in front is added here, so it is never part of the match.
-const REVIEW_PATH = `${await Deno.makeTempDir()}/review.md`;
+const REVIEW_DIR = await Deno.makeTempDir();
+const REVIEW_PATH = `${REVIEW_DIR}/review.md`;
 const VERDICTS: Record<string, [event: string, mark: string]> = {
   Approved: ["APPROVED", "✅"],
   "Changes requested": ["REQUEST_CHANGES", "🛑"],
 };
 
+// A finding about one line is posted on that line of the diff rather than as
+// `file:line` prose in the body. Those anchors come as JSON, so the file and
+// line are structured instead of parsed back out of English; a malformed entry
+// fails the run, because a silently dropped finding is worse than a red run.
+const ANCHORS_PATH = `${REVIEW_DIR}/anchors.json`;
+type Anchor = { path: string; line: number; side: "new" | "old"; body: string };
+
+function parseAnchors(text: string): Anchor[] {
+  const entries: unknown = JSON.parse(text);
+  if (!Array.isArray(entries)) throw new Error(`${ANCHORS_PATH}: not an array`);
+  return entries.map((entry: unknown, index) => {
+    const at = `${ANCHORS_PATH}[${index}]`;
+    if (typeof entry !== "object" || entry === null) {
+      throw new Error(`${at}: not an object`);
+    }
+    const { path, line, side = "new", body } = entry as Record<string, unknown>;
+    if (typeof path !== "string" || path === "") {
+      throw new Error(`${at}.path: expected a repository path`);
+    }
+    if (typeof line !== "number" || !Number.isInteger(line) || line < 1) {
+      throw new Error(`${at}.line: expected a line number`);
+    }
+    if (side !== "new" && side !== "old") {
+      throw new Error(`${at}.side: expected "new" or "old"`);
+    }
+    if (typeof body !== "string" || body.trim() === "") {
+      throw new Error(`${at}.body: expected the finding`);
+    }
+    return { path, line, side, body };
+  });
+}
+
+async function readAnchors(): Promise<Anchor[]> {
+  const written = await Deno.readTextFile(ANCHORS_PATH).catch(() => null);
+  return written === null ? [] : parseAnchors(written);
+}
+
 async function postResult(body: string): Promise<void> {
   const review = await Deno.readTextFile(REVIEW_PATH).catch(() => null);
   if (review === null) {
@@ -80,9 +118,25 @@ async function postResult(body: string): Promise<void> {
   }
   const [verdict, ...rest] = review.split("\n");
   const [event, mark] = VERDICTS[verdict.trim()] ?? ["COMMENT", "💬"];
-  await gitea(REVIEWER_TOKEN, `repos/${REPO}/pulls/${INDEX}/reviews`, {
-    body: stripAnsi([`${mark} ${verdict.trim()}`, ...rest].join("\n")),
-    event,
+  const post = (anchors: Anchor[]) =>
+    gitea(REVIEWER_TOKEN, `repos/${REPO}/pulls/${INDEX}/reviews`, {
+      body: stripAnsi([`${mark} ${verdict.trim()}`, ...rest].join("\n")),
+      event,
+      comments: anchors.map(({ path, line, side, body }) => ({
+        path,
+        body: stripAnsi(body),
+        new_position: side === "new" ? line : 0,
+        old_position: side === "old" ? line : 0,
+      })),
+    });
+  const anchors = await readAnchors();
+  // Gitea rejects the whole review when an anchor names a line outside the
+  // diff, and a verdict that never lands blocks the pull request, so the body
+  // goes up alone rather than not at all.
+  await post(anchors).catch(async (error: Error) => {
+    if (anchors.length === 0) throw error;
+    console.error(`inline comments rejected: ${error.message}`);
+    await post([]);
   });
 }
 
@@ -128,6 +182,7 @@ async function renderPrompt(): Promise<string> {
     GITEA_REPOSITORY: REPO,
     ISSUE_INDEX: INDEX,
     REVIEW_PATH,
+    ANCHORS_PATH,
   };
   const template = await Deno.readTextFile(
     new URL("prompt.md", import.meta.url),