Invite bot to server / group for #8.

src/database/entities/channel.rs

@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use crate::database::*;
 use crate::notifications::events::ClientboundNotification;
 use crate::util::result::{Error, Result};
+use crate::util::variables::MAX_GROUP_SIZE;
 use futures::StreamExt;
 use mongodb::bson::Bson;
 use mongodb::{
@@ -344,4 +345,53 @@ impl Channel {
 
         Ok(())
     }
+
+    pub async fn add_to_group(&self, member: String, by_user: String) -> Result<()> {
+        if let Channel::Group { id, recipients, .. } = &self {
+            if recipients.len() >= *MAX_GROUP_SIZE {
+                Err(Error::GroupTooLarge {
+                    max: *MAX_GROUP_SIZE,
+                })?
+            }
+
+            if recipients.iter().find(|x| *x == &member).is_some() {
+                Err(Error::AlreadyInGroup)?
+            }
+
+            get_collection("channels")
+                .update_one(
+                    doc! {
+                        "_id": &id
+                    },
+                    doc! {
+                        "$push": {
+                            "recipients": &member
+                        }
+                    },
+                    None,
+                )
+                .await
+                .map_err(|_| Error::DatabaseError {
+                    operation: "update_one",
+                    with: "channel",
+                })?;
+
+            ClientboundNotification::ChannelGroupJoin {
+                id: id.clone(),
+                user: member.clone(),
+            }
+            .publish(id.clone());
+
+            Content::SystemMessage(SystemMessage::UserAdded {
+                id: member,
+                by: by_user,
+            })
+            .send_as_system(&self)
+            .await
+            .ok();
+            Ok(())
+        } else {
+            Err(Error::InvalidOperation)
+        }
+    }
 }

src/database/guards/reference.rs

@@ -61,6 +61,10 @@ impl Ref {
         self.fetch("channel_invites").await
     }
 
+    pub async fn fetch_bot(&self) -> Result<Bot> {
+        self.fetch("bots").await
+    }
+
     pub async fn fetch_member(&self, server: &str) -> Result<Member> {
         let doc = get_collection("server_members")
             .find_one(