feat: set up github endpoint

src/modules/processGitHubEvent.ts

@@ -0,0 +1,43 @@
+/**
+ * @copyright NHCarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import type { IssueCreated,
+  PullRequestCreated,
+  GithubPayload } from "../interfaces/github.js";
+import type { FastifyRequest, FastifyReply } from "fastify";
+
+const isIssue = (body: GithubPayload): body is IssueCreated => {
+  return "issue" in body;
+};
+
+const isPull = (body: GithubPayload): body is PullRequestCreated => {
+  return "pull_request" in body;
+};
+
+/**
+ * Handles a payload from a GitHub webhook.
+ * @param request - The Fastify request payload.
+ * @param response - The Fastify reply class.
+ */
+export const processGithubEvent = async(
+  // eslint-disable-next-line @typescript-eslint/naming-convention -- Fastify standard.
+  request: FastifyRequest<{ Body: GithubPayload }>,
+  response: FastifyReply,
+): Promise<void> => {
+  const event = request.headers["x-github-event"];
+  if (typeof event !== "string") {
+    await response.status(400).
+      send({ message: "Invalid GitHub event header." });
+    return;
+  }
+  if (event === "ping") {
+    await response.status(200).send({ message: "Pong!" });
+    return;
+  }
+  const { action: _action } = request.body;
+  isIssue(request.body);
+  isPull(request.body);
+};