create RawCall trait, that will contain DB methods to call from script runtime

src/db/mod.rs

@@ -2,6 +2,7 @@ pub mod application;
 pub mod bots;
 pub mod callback_info;
 pub mod message_forward;
+pub mod raw_calls;
 
 use std::time::Duration;
 

src/db/raw_calls.rs

@@ -0,0 +1,38 @@
+use mongodb::Database;
+
+use super::CallDB;
+use serde_json::Value;
+
+#[derive(thiserror::Error, Debug)]
+pub enum RawCallError {
+    #[error("error while processing mongodb query: {0}")]
+    MongodbError(#[from] mongodb::error::Error),
+    #[error("error while buildint bson's query document: {0}")]
+    DocumentError(#[from] mongodb::bson::extjson::de::Error),
+    #[error("error when expected map: {0}")]
+    NotAMapError(String),
+}
+pub type RawCallResult<T> = Result<T, RawCallError>;
+
+pub trait RawCall {
+    async fn get_database(&mut self) -> Database;
+    async fn find_one(&mut self, collection: &str, query: Value) -> RawCallResult<Option<Value>> {
+        let db = self.get_database().await;
+        let value = db.collection::<Value>(collection);
+
+        let map = match query {
+            Value::Object(map) => map,
+            _ => return Err(RawCallError::NotAMapError("query is not a map".to_string())),
+        };
+
+        let doc = map.try_into()?;
+        let ret = value.find_one(doc).await?;
+        Ok(ret)
+    }
+}
+
+impl<T: CallDB> RawCall for T {
+    async fn get_database(&mut self) -> Database {
+        CallDB::get_database(self).await
+    }
+}