feat: initial prototype (#6)

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### Attestations

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

### Dependencies

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

### Style

- [ ] I have run the linter and resolved any errors.
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### 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.
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Reviewed-on: #6
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src/utils/checkEntitlement.ts

@@ -0,0 +1,32 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { entitledGuilds } from "../config/entitlements.js";
+import type { Liora } from "../interfaces/liora.js";
+import type { Guild } from "discord.js";
+
+/**
+ * Checks if a guild has subscribed.
+ * @param liora - Liora's Discord instance.
+ * @param guild - The guild to check.
+ * @returns A boolean indicating whether the guild has an active subscription.
+ */
+const checkGuildEntitlement = async(
+  liora: Liora,
+  guild: Guild,
+): Promise<boolean> => {
+  if (entitledGuilds.includes(guild.id)) {
+    return true;
+  }
+  const entitlements = await liora.discord.application?.entitlements.fetch({
+    excludeDeleted: true,
+    excludeEnded:   true,
+    guild:          guild,
+  });
+  return Boolean(entitlements && entitlements.size > 0);
+};
+
+export { checkGuildEntitlement };

src/utils/errorHandler.ts

@@ -0,0 +1,28 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { logger } from "./logger.js";
+
+/**
+ * Generates a UUID for an error, sends the error to the logger,
+ * and returns the UUID to be shared with the user.
+ * @param error - The error to log.
+ * @param context - The context in which the error occurred.
+ * @returns A UUID string assigned to the error.
+ */
+export const errorHandler = async(
+  error: unknown,
+  context: string,
+): Promise<string> => {
+  const id = crypto.randomUUID();
+  await logger.error(
+    `${context} - Error ID: ${id}`,
+    error instanceof Error
+      ? error
+      : new Error(String(error)),
+  );
+  return id;
+};

src/utils/logger.ts

@@ -0,0 +1,12 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { Logger } from "@nhcarrigan/logger";
+
+export const logger = new Logger(
+  "Liora",
+  process.env.LOG_TOKEN ?? "",
+);