add guildData helper library

src/lib/guildData.js

@@ -0,0 +1,64 @@
+hf.database.run(
+  "CREATE TABLE IF NOT EXISTS guild_data (key STRING PRIMARY KEY, value STRING NOT NULL) WITHOUT ROWID"
+);
+
+function setGuildData(id, key, value) {
+  return new Promise((resolve, reject) => {
+    hf.database.run(
+      "REPLACE INTO guild_data VALUES ($key,$value)",
+      {
+        $value: value,
+        $key: `${id}[${key}]`,
+      },
+      (err) => {
+        if (err == null) {
+          resolve(true);
+        } else {
+          reject(err);
+        }
+      }
+    );
+  });
+}
+
+function getGuildData(id, key, fallback = null) {
+  return new Promise((resolve, reject) => {
+    hf.database.get(
+      "SELECT value FROM guild_data WHERE key = $key",
+      {
+        $key: `${id}[${key}]`,
+      },
+      (err, row) => {
+        if (err == null) {
+          resolve(row?.value || fallback);
+        } else {
+          reject(err);
+        }
+      }
+    );
+  });
+}
+
+function deleteGuildData(id, key) {
+  return new Promise((resolve, reject) => {
+    hf.database.run(
+      "DELETE FROM guild_data WHERE key = $key",
+      {
+        $key: `${id}[${key}]`,
+      },
+      (err) => {
+        if (err == null) {
+          resolve(true);
+        } else {
+          reject(err);
+        }
+      }
+    );
+  });
+}
+
+module.exports = {
+  setGuildData,
+  getGuildData,
+  deleteGuildData,
+};