//! Handling of all client2server presence stanzas

use anyhow::Result;
use quick_xml::events::Event;

use lavina_core::room::RoomId;
use proto_xmpp::bind::{Jid, Name, Resource, Server};
use proto_xmpp::client::{Message, MessageType, Presence, Subject};
use proto_xmpp::muc::{Affiliation, Delay, Role, XUser, XUserItem, XmppHistoryMessage};
use proto_xmpp::xml::{Ignore, ToXml};

use crate::XmppConnection;

impl<'a> XmppConnection<'a> {
    #[tracing::instrument(skip(self, output, p), name = "XmppConnection::handle_presence")]
    pub async fn handle_presence(&mut self, output: &mut Vec<Event<'static>>, p: Presence<Ignore>) -> Result<()> {
        match p.to {
            None => {
                self.self_presence(output, p.r#type.as_deref()).await;
            }
            Some(Jid {
                name: Some(name),
                server,
                // resources in MUCs are members' personas – not implemented (yet?)
                resource: Some(_),
            }) if server.0 == self.hostname_rooms => match p.r#type.as_deref() {
                None => {
                    self.join_muc(output, p.id, name).await?;
                }
                Some("unavailable") => {
                    self.leave_muc(output, p.id, name).await?;
                }
                _ => {
                    tracing::error!("Unimplemented case")
                }
            },
            _ => {
                // TODO other presence cases
                let response = Presence::<()>::default();
                response.serialize(output);
            }
        }
        Ok(())
    }

    async fn join_muc(&mut self, output: &mut Vec<Event<'static>>, id: Option<String>, name: Name) -> Result<()> {
        // Response presence
        let mut muc_presence = self.retrieve_muc_presence(&name).await?;
        muc_presence.id = id;
        muc_presence.serialize(output);

        // N last messages from the room history before the user joined
        let messages = self.retrieve_message_history(&name).await?;
        for message in messages {
            message.serialize(output)
        }

        // The subject is the last stanza sent during a MUC join process.
        let subject = Message::<()> {
            from: Some(Jid {
                name: Some(name.clone()),
                server: Server(self.hostname_rooms.clone()),
                resource: None,
            }),
            id: None,
            to: Some(Jid {
                name: Some(self.user.xmpp_name.clone()),
                server: Server(self.hostname.clone()),
                resource: Some(self.user.xmpp_resource.clone()),
            }),
            r#type: MessageType::Groupchat,
            lang: None,
            subject: Some(Subject(None)),
            body: None,
            custom: vec![],
        };
        subject.serialize(output);
        Ok(())
    }

    async fn leave_muc(&mut self, output: &mut Vec<Event<'static>>, id: Option<String>, name: Name) -> Result<()> {
        self.user_handle.leave_room(RoomId::try_from(name.0.clone())?).await?;
        let response = Presence {
            id,
            to: Some(Jid {
                name: Some(self.user.xmpp_name.clone()),
                server: Server(self.hostname.clone()),
                resource: Some(self.user.xmpp_resource.clone()),
            }),
            from: Some(Jid {
                name: Some(name.clone()),
                server: Server(self.hostname_rooms.clone()),
                resource: Some(self.user.xmpp_muc_name.clone()),
            }),
            r#type: Some("unavailable".into()),
            custom: vec![XUser {
                item: XUserItem {
                    affiliation: Affiliation::Member,
                    role: Role::None,
                    jid: Jid {
                        name: Some(self.user.xmpp_name.clone()),
                        server: Server(self.hostname.clone()),
                        resource: Some(self.user.xmpp_resource.clone()),
                    },
                },
                self_presence: true,
                just_created: false,
            }],
            ..Default::default()
        };
        response.serialize(output);
        Ok(())
    }

    #[tracing::instrument(skip(self, output, r#type), name = "XmppConnection::self_presence")]
    async fn self_presence(&mut self, output: &mut Vec<Event<'static>>, r#type: Option<&str>) {
        match r#type {
            Some("unavailable") => {
                // do not print anything
            }
            None => {
                let response = Presence::<()> {
                    to: Some(Jid {
                        name: Some(self.user.xmpp_name.clone()),
                        server: Server(self.hostname.clone()),
                        resource: Some(self.user.xmpp_resource.clone()),
                    }),
                    from: Some(Jid {
                        name: Some(self.user.xmpp_name.clone()),
                        server: Server(self.hostname.clone()),
                        resource: Some(self.user.xmpp_resource.clone()),
                    }),
                    ..Default::default()
                };
                response.serialize(output);
            }
            e => {
                tracing::error!("TODO: unknown presence type: {e:?}");
            }
        }
    }

    #[tracing::instrument(skip(self), name = "XmppConnection::retrieve_muc_presence")]
    async fn retrieve_muc_presence(&mut self, name: &Name) -> Result<Presence<XUser>> {
        let _ = self.user_handle.join_room(RoomId::try_from(name.0.clone())?).await?;
        // TODO handle bans
        let response = Presence {
            to: Some(Jid {
                name: Some(self.user.xmpp_name.clone()),
                server: Server(self.hostname.clone()),
                resource: Some(self.user.xmpp_resource.clone()),
            }),
            from: Some(Jid {
                name: Some(name.clone()),
                server: Server(self.hostname_rooms.clone()),
                resource: Some(self.user.xmpp_muc_name.clone()),
            }),
            custom: vec![XUser {
                item: XUserItem {
                    affiliation: Affiliation::Member,
                    role: Role::Participant,
                    jid: Jid {
                        name: Some(self.user.xmpp_name.clone()),
                        server: Server(self.hostname.clone()),
                        resource: Some(self.user.xmpp_resource.clone()),
                    },
                },
                self_presence: true,
                just_created: false, // TODO we don't know this for sure at this point
            }],
            ..Default::default()
        };
        Ok(response)
    }

    /// Retrieve a room's message history. The output can be serialized into a stream of XML stanzas.
    ///
    /// Example in [XmppHistoryMessage]'s docs.
    #[tracing::instrument(skip(self), name = "XmppConnection::retrieve_message_history")]
    async fn retrieve_message_history(&self, room_name: &Name) -> Result<Vec<XmppHistoryMessage>> {
        let room_id = RoomId::try_from(room_name.0.clone())?;
        let history_messages = self.user_handle.get_room_message_history(room_id).await?;
        let mut response = vec![];

        for history_message in history_messages.into_iter() {
            response.push(XmppHistoryMessage {
                id: history_message.id.to_string(),
                to: Jid {
                    name: Option::from(Name(self.user.xmpp_muc_name.0.clone().into())),
                    server: Server(self.hostname.clone()),
                    resource: None,
                },
                from: Jid {
                    name: Option::from(room_name.clone()),
                    server: Server(self.hostname_rooms.clone()),
                    resource: Option::from(Resource(history_message.author_name.clone().into())),
                },
                delay: Delay {
                    from: Jid {
                        name: Option::from(Name(history_message.author_name.clone().into())),
                        server: Server(self.hostname_rooms.clone()),
                        resource: None,
                    },
                    stamp: history_message.created_at.to_rfc3339(),
                },
                body: history_message.content.clone(),
            });
            tracing::info!(
                "Retrieved message: {:?} {:?}",
                history_message.author_name,
                history_message.content.clone()
            );
        }

        return Ok(response);
    }
}

#[cfg(test)]
mod tests {
    use anyhow::Result;

    use lavina_core::player::PlayerId;
    use proto_xmpp::bind::{Jid, Name, Resource, Server};
    use proto_xmpp::client::Presence;
    use proto_xmpp::muc::{Affiliation, Role, XUser, XUserItem};

    use crate::testkit::{expect_user_authenticated, TestServer};
    use crate::Authenticated;

    #[tokio::test]
    async fn test_muc_joining() -> Result<()> {
        let server = TestServer::start().await.unwrap();

        server.core.create_player(&PlayerId::from("tester")?).await?;

        let player_id = PlayerId::from("tester").unwrap();
        let user = Authenticated {
            player_id,
            xmpp_name: Name("tester".into()),
            xmpp_resource: Resource("tester".into()),
            xmpp_muc_name: Resource("tester".into()),
        };

        let mut player_conn = server.core.connect_to_player(&user.player_id).await;
        let mut conn = expect_user_authenticated(&server, &user, &mut player_conn).await.unwrap();

        let muc_presence = conn.retrieve_muc_presence(&user.xmpp_name).await.unwrap();
        let expected = Presence {
            to: Some(Jid {
                name: Some(conn.user.xmpp_name.clone()),
                server: Server(conn.hostname.clone()),
                resource: Some(conn.user.xmpp_resource.clone()),
            }),
            from: Some(Jid {
                name: Some(user.xmpp_name.clone()),
                server: Server(conn.hostname_rooms.clone()),
                resource: Some(conn.user.xmpp_muc_name.clone()),
            }),
            custom: vec![XUser {
                item: XUserItem {
                    affiliation: Affiliation::Member,
                    role: Role::Participant,
                    jid: Jid {
                        name: Some(conn.user.xmpp_name.clone()),
                        server: Server(conn.hostname.clone()),
                        resource: Some(conn.user.xmpp_resource.clone()),
                    },
                },
                self_presence: true,
                just_created: false,
            }],
            ..Default::default()
        };
        assert_eq!(expected, muc_presence);

        server.shutdown().await.unwrap();
        Ok(())
    }

    // Test that joining a room second time after a server restart,
    // i.e. in-memory cache of memberships is cleaned, does not cause any issues.
    #[tokio::test]
    async fn test_muc_joining_twice() -> Result<()> {
        let server = TestServer::start().await.unwrap();

        server.core.create_player(&PlayerId::from("tester")?).await?;

        let player_id = PlayerId::from("tester").unwrap();
        let user = Authenticated {
            player_id,
            xmpp_name: Name("tester".into()),
            xmpp_resource: Resource("tester".into()),
            xmpp_muc_name: Resource("tester".into()),
        };

        let mut player_conn = server.core.connect_to_player(&user.player_id).await;
        let mut conn = expect_user_authenticated(&server, &user, &mut player_conn).await.unwrap();

        let response = conn.retrieve_muc_presence(&user.xmpp_name).await.unwrap();
        let expected = Presence {
            to: Some(Jid {
                name: Some(conn.user.xmpp_name.clone()),
                server: Server(conn.hostname.clone()),
                resource: Some(conn.user.xmpp_resource.clone()),
            }),
            from: Some(Jid {
                name: Some(user.xmpp_name.clone()),
                server: Server(conn.hostname_rooms.clone()),
                resource: Some(conn.user.xmpp_muc_name.clone()),
            }),
            custom: vec![XUser {
                item: XUserItem {
                    affiliation: Affiliation::Member,
                    role: Role::Participant,
                    jid: Jid {
                        name: Some(conn.user.xmpp_name.clone()),
                        server: Server(conn.hostname.clone()),
                        resource: Some(conn.user.xmpp_resource.clone()),
                    },
                },
                self_presence: true,
                just_created: false,
            }],
            ..Default::default()
        };
        assert_eq!(expected, response);

        drop(conn);
        let server = server.reboot().await.unwrap();

        let mut player_conn = server.core.connect_to_player(&user.player_id).await;
        let mut conn = expect_user_authenticated(&server, &user, &mut player_conn).await.unwrap();

        let response = conn.retrieve_muc_presence(&user.xmpp_name).await.unwrap();
        assert_eq!(expected, response);

        server.shutdown().await.unwrap();
        Ok(())
    }
}