Iron out naming / text, update docs for Heroku integration

backend/src/services/project-bot/project-bot-fns.ts

@@ -0,0 +1,36 @@
+import { SecretKeyEncoding } from "@app/db/schemas";
+import { decryptAsymmetric, infisicalSymmetricDecrypt } from "@app/lib/crypto/encryption";
+import { BadRequestError } from "@app/lib/errors";
+import { TProjectBotDALFactory } from "@app/services/project-bot/project-bot-dal";
+
+import { TGetPrivateKeyDTO } from "./project-bot-types";
+
+export const getBotPrivateKey = ({ bot }: TGetPrivateKeyDTO) =>
+  infisicalSymmetricDecrypt({
+    keyEncoding: bot.keyEncoding as SecretKeyEncoding,
+    iv: bot.iv,
+    tag: bot.tag,
+    ciphertext: bot.encryptedPrivateKey
+  });
+
+export const getBotKeyFnFactory = (projectBotDAL: TProjectBotDALFactory) => {
+  const getBotKeyFn = async (projectId: string) => {
+    const bot = await projectBotDAL.findOne({ projectId });
+
+    if (!bot) throw new BadRequestError({ message: "failed to find bot key" });
+    if (!bot.isActive) throw new BadRequestError({ message: "Bot is not active" });
+    if (!bot.encryptedProjectKeyNonce || !bot.encryptedProjectKey)
+      throw new BadRequestError({ message: "Encryption key missing" });
+
+    const botPrivateKey = getBotPrivateKey({ bot });
+
+    return decryptAsymmetric({
+      ciphertext: bot.encryptedProjectKey,
+      privateKey: botPrivateKey,
+      nonce: bot.encryptedProjectKeyNonce,
+      publicKey: bot.sender.publicKey
+    });
+  };
+
+  return getBotKeyFn;
+};