feat: client and server logic to manage announcements (#3)

### Explanation

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### Issue

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### Attestations

- [x] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [x] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [x] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [x] I have pinned the dependencies to a specific patch version.

### Style

- [x] I have run the linter and resolved any errors.
- [x] My pull request uses an appropriate title, matching the conventional commit standards.
- [x] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [ ] All new and existing tests pass locally with my changes.
- [ ] Code coverage remains at or above the configured threshold.

### Documentation

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### Versioning

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Reviewed-on: #3
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

server/src/modules/announceOnDiscord.ts

@@ -0,0 +1,65 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+/* eslint-disable @typescript-eslint/naming-convention -- we are making raw API calls. */
+
+const channelIds = {
+  community: "1386105484313886820",
+  products:  "1386105452881776661",
+} as const;
+const roleIds = {
+  community: "1386107941224054895",
+  products:  "1386107909699666121",
+} as const;
+
+/**
+ * Forwards an announcement to our Discord server.
+ * @param title - The title of the announcement.
+ * @param content - The main body of the announcement.
+ * @param type - Whether the announcement is for a product or community.
+ * @returns A message indicating the success or failure of the operation.
+ */
+export const announceOnDiscord = async(
+  title: string,
+  content: string,
+  type: "products" | "community",
+): Promise<string> => {
+  const messageRequest = await fetch(
+    `https://discord.com/api/v10/channels/${channelIds[type]}/messages`,
+    {
+      body: JSON.stringify({
+        allowed_mentions: { parse: [ "users", "roles" ] },
+        content:          `# ${title}\n\n${content}\n-# <@&${roleIds[type]}>`,
+      }),
+      headers: {
+        "Authorization": `Bot ${process.env.DISCORD_TOKEN ?? ""}`,
+        "Content-Type":  "application/json",
+      },
+      method: "POST",
+    },
+  );
+  if (messageRequest.status !== 200) {
+    return "Failed to send message to Discord.";
+  }
+  // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- fetch does not accept generics.
+  const message = await messageRequest.json() as { id?: string };
+  if (message.id === undefined) {
+    return "Failed to parse message ID, cannot crosspost.";
+  }
+  const crosspostRequest = await fetch(
+    `https://discord.com/api/v10/channels/${channelIds[type]}/messages/${message.id}/crosspost`,
+    {
+      headers: {
+        "Authorization": `Bot ${process.env.DISCORD_TOKEN ?? ""}`,
+        "Content-Type":  "application/json",
+      },
+      method: "POST",
+    },
+  );
+  if (!crosspostRequest.ok) {
+    return "Failed to crosspost message to Discord.";
+  }
+  return "Successfully sent and published message to Discord.";
+};

server/src/modules/announceOnForum.ts

@@ -0,0 +1,40 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+/* eslint-disable @typescript-eslint/naming-convention -- we are making raw API calls. */
+/**
+ * Forwards an announcement to our Discord server.
+ * @param title - The title of the announcement.
+ * @param content - The main body of the announcement.
+ * @param type - Whether the announcement is for a product or community.
+ * @returns A message indicating the success or failure of the operation.
+ */
+export const announceOnForum = async(
+  title: string,
+  content: string,
+  type: "products" | "community",
+): Promise<string> => {
+  const forumRequest = await fetch(
+    `https://forum.nhcarrigan.com/posts.json`,
+    {
+      body: JSON.stringify({
+        category: 14,
+        raw:      content,
+        tags:     [ type ],
+        title:    title,
+      }),
+      headers: {
+        "Api-Key":      process.env.FORUM_API_KEY ?? "",
+        "Api-Username": "Hikari",
+        "Content-Type": "application/json",
+      },
+      method: "POST",
+    },
+  );
+  if (forumRequest.status !== 200) {
+    return "Failed to send message to forum.";
+  }
+  return "Successfully sent message to forum.";
+};

server/src/modules/getIpFromRequest.ts

@@ -0,0 +1,25 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import type { FastifyRequest } from "fastify";
+
+/**
+ * Parses an IP address from a request, first looking for the
+ * Cloudflare headers, then falling back to the request IP.
+ * @param request - The Fastify request object.
+ * @returns The IP address as a string.
+ */
+export const getIpFromRequest = (request: FastifyRequest): string => {
+  const header
+    = request.headers["X-Forwarded-For"] ?? request.headers["Cf-Connecting-IP"];
+  if (typeof header === "string") {
+    return header;
+  }
+  if (Array.isArray(header)) {
+    return header[0] ?? header.join(", ");
+  }
+  return request.ip;
+};