Friends functionality (#90)

### Description

Implements and closes #86

### Game

Robocraft

### Please confirm

- [x] I am the legal owner or represent the owner of all work submitted
- [x] I consent to my submission being added to this FOSS project
- [ ] This PR used LLMs to generate some or all of the code changes

Reviewed-on: https://git.ngram.ca/OpenJam/rc-servers/pulls/90
Co-authored-by: NG (Graham) <ngniusness@gmail.com>
Co-committed-by: NG (Graham) <ngniusness@gmail.com>

rc_database/src/schema/friend.rs

@@ -0,0 +1,59 @@
+use sea_orm::entity::prelude::*;
+
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "friends")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: i32,
+    pub creation_time: i64, // seconds since unix epoch
+    pub friend_source: i32,
+    pub friend_target: i32,
+    pub state: FriendStatus,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::FriendSource",
+        to = "super::user::Column::Id"
+    )]
+    Source,
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::FriendTarget",
+        to = "super::user::Column::Id"
+    )]
+    Target,
+}
+
+/*impl Related<super::user::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::Source.def()
+    }
+}*/
+
+impl Related<super::user::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::Target.def()
+    }
+}
+
+impl ActiveModelBehavior for ActiveModel {}
+
+#[derive(Clone, Debug, PartialEq, Eq, EnumIter, DeriveActiveEnum)]
+#[sea_orm(rs_type = "String", db_type = "String(StringLen::None)", rename_all = "PascalCase")]
+pub enum FriendStatus {
+    InviteSent,
+    InvitePending,
+    Accepted,
+    Declined,
+    Cancelled,
+    Removed,
+}
+
+pub const FINAL_STATUSES: [FriendStatus; 3] = [
+    FriendStatus::Declined,
+    FriendStatus::Cancelled,
+    FriendStatus::Removed,
+];

rc_database/src/schema/mod.rs

@@ -12,6 +12,7 @@ pub mod game_event;
 pub mod multiplayer_game_score;
 #[cfg(feature = "factory")]
 pub mod factory;
+pub mod friend;
 
 pub fn parse_int_csv(s: &str) -> Vec<u32> {
     s.split(',').filter_map(|i_as_s| {

rc_database/src/schema/user.rs

@@ -27,6 +27,8 @@ pub enum Relation {
     Player,
     #[sea_orm(has_many = "super::factory::vehicle::Entity")]
     FactoryUploads,
+    #[sea_orm(has_many = "super::friend::Entity")]
+    Friends, // this will probably join the wrong column (i.e. in the wrong direction)
 }
 
 impl Related<super::permissions::Entity> for Entity {
@@ -65,4 +67,10 @@ impl Related<super::factory::vehicle::Entity> for Entity {
     }
 }
 
+impl Related<super::friend::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::Friends.def()
+    }
+}
+
 impl ActiveModelBehavior for ActiveModel {}