AppFlowy/frontend/rust-lib/flowy-document/src/services/doc/edit/queue.rs

use async_stream::stream;

use flowy_collaboration::{
    document::{history::UndoResult, Document, NewlineDoc},
    entities::revision::Revision,
    errors::CollaborateError,
    util::make_delta_from_revisions,
};
use flowy_error::FlowyError;
use futures::stream::StreamExt;
use lib_ot::{
    core::{Interval, OperationTransformable},
    rich_text::{RichTextAttribute, RichTextDelta},
};
use std::sync::Arc;
use tokio::sync::{mpsc, oneshot, RwLock};

pub(crate) struct EditorCommandQueue {
    #[allow(dead_code)]
    doc_id: String,
    document: Arc<RwLock<Document>>,
    receiver: Option<mpsc::UnboundedReceiver<EditorCommand>>,
}

impl EditorCommandQueue {
    pub(crate) fn new(doc_id: &str, delta: RichTextDelta, receiver: mpsc::UnboundedReceiver<EditorCommand>) -> Self {
        let document = Arc::new(RwLock::new(Document::from_delta(delta)));
        Self {
            doc_id: doc_id.to_owned(),
            document,
            receiver: Some(receiver),
        }
    }

    pub(crate) async fn run(mut self) {
        let mut receiver = self.receiver.take().expect("Should only call once");
        let stream = stream! {
            loop {
                match receiver.recv().await {
                    Some(msg) => yield msg,
                    None => break,
                }
            }
        };
        stream
            .for_each(|msg| async {
                match self.handle_message(msg).await {
                    Ok(_) => {},
                    Err(e) => tracing::debug!("[EditCommandQueue]: {}", e),
                }
            })
            .await;
    }

    async fn handle_message(&self, msg: EditorCommand) -> Result<(), FlowyError> {
        match msg {
            EditorCommand::ComposeDelta { delta, ret } => {
                let fut = || async {
                    let mut document = self.document.write().await;
                    let _ = document.compose_delta(delta)?;
                    let md5 = document.md5();
                    drop(document);

                    Ok::<String, CollaborateError>(md5)
                };

                let _ = ret.send(fut().await);
            },
            EditorCommand::OverrideDelta { delta, ret } => {
                let fut = || async {
                    let mut document = self.document.write().await;
                    let _ = document.set_delta(delta);
                    let md5 = document.md5();
                    drop(document);
                    Ok::<String, CollaborateError>(md5)
                };

                let _ = ret.send(fut().await);
            },
            EditorCommand::TransformRevision { revisions, ret } => {
                let f = || async {
                    let new_delta = make_delta_from_revisions(revisions)?;
                    let read_guard = self.document.read().await;
                    let mut server_prime: Option<RichTextDelta> = None;
                    let client_prime: RichTextDelta;
                    if read_guard.is_empty::<NewlineDoc>() {
                        // Do nothing
                        client_prime = new_delta;
                    } else {
                        let (s_prime, c_prime) = read_guard.delta().transform(&new_delta)?;
                        client_prime = c_prime;
                        server_prime = Some(s_prime);
                    }

                    drop(read_guard);
                    Ok::<TransformDeltas, CollaborateError>(TransformDeltas {
                        client_prime,
                        server_prime,
                    })
                };
                let _ = ret.send(f().await);
            },
            EditorCommand::Insert { index, data, ret } => {
                let mut write_guard = self.document.write().await;
                let delta = write_guard.insert(index, data)?;
                let md5 = write_guard.md5();
                let _ = ret.send(Ok((delta, md5)));
            },
            EditorCommand::Delete { interval, ret } => {
                let mut write_guard = self.document.write().await;
                let delta = write_guard.delete(interval)?;
                let md5 = write_guard.md5();
                let _ = ret.send(Ok((delta, md5)));
            },
            EditorCommand::Format {
                interval,
                attribute,
                ret,
            } => {
                let mut write_guard = self.document.write().await;
                let delta = write_guard.format(interval, attribute)?;
                let md5 = write_guard.md5();
                let _ = ret.send(Ok((delta, md5)));
            },
            EditorCommand::Replace { interval, data, ret } => {
                let mut write_guard = self.document.write().await;
                let delta = write_guard.replace(interval, data)?;
                let md5 = write_guard.md5();
                let _ = ret.send(Ok((delta, md5)));
            },
            EditorCommand::CanUndo { ret } => {
                let _ = ret.send(self.document.read().await.can_undo());
            },
            EditorCommand::CanRedo { ret } => {
                let _ = ret.send(self.document.read().await.can_redo());
            },
            EditorCommand::Undo { ret } => {
                let result = self.document.write().await.undo();
                let _ = ret.send(result);
            },
            EditorCommand::Redo { ret } => {
                let result = self.document.write().await.redo();
                let _ = ret.send(result);
            },
            EditorCommand::ReadDoc { ret } => {
                let data = self.document.read().await.to_json();
                let _ = ret.send(Ok(data));
            },
            EditorCommand::ReadDocDelta { ret } => {
                let delta = self.document.read().await.delta().clone();
                let _ = ret.send(Ok(delta));
            },
        }
        Ok(())
    }
}

pub(crate) type Ret<T> = oneshot::Sender<Result<T, CollaborateError>>;
pub(crate) type NewDelta = (RichTextDelta, String);
pub(crate) type DocumentMD5 = String;

#[allow(dead_code)]
pub(crate) enum EditorCommand {
    ComposeDelta {
        delta: RichTextDelta,
        ret: Ret<DocumentMD5>,
    },
    OverrideDelta {
        delta: RichTextDelta,
        ret: Ret<DocumentMD5>,
    },
    TransformRevision {
        revisions: Vec<Revision>,
        ret: Ret<TransformDeltas>,
    },
    Insert {
        index: usize,
        data: String,
        ret: Ret<NewDelta>,
    },
    Delete {
        interval: Interval,
        ret: Ret<NewDelta>,
    },
    Format {
        interval: Interval,
        attribute: RichTextAttribute,
        ret: Ret<NewDelta>,
    },

    Replace {
        interval: Interval,
        data: String,
        ret: Ret<NewDelta>,
    },
    CanUndo {
        ret: oneshot::Sender<bool>,
    },
    CanRedo {
        ret: oneshot::Sender<bool>,
    },
    Undo {
        ret: Ret<UndoResult>,
    },
    Redo {
        ret: Ret<UndoResult>,
    },
    ReadDoc {
        ret: Ret<String>,
    },
    ReadDocDelta {
        ret: Ret<RichTextDelta>,
    },
}

pub(crate) struct TransformDeltas {
    pub client_prime: RichTextDelta,
    pub server_prime: Option<RichTextDelta>,
}