//! Forward log messages to logging webxdc
use crate::chat::ChatId;
use crate::config::Config;
use crate::context::Context;
use crate::events::EventType;
use crate::message::{Message, MsgId, Viewtype};
use crate::param::Param;
use crate::tools::time;
use crate::webxdc::StatusUpdateItem;
use async_channel::{self as channel, Receiver, Sender};
use serde_json::json;
use tokio::task;

#[derive(Debug)]
pub(crate) struct DebugLogging {
    /// The message containing the logging xdc
    pub(crate) msg_id: MsgId,
    /// Handle to the background task responsible for sending
    pub(crate) loop_handle: task::JoinHandle<()>,
    /// Channel that log events should be sent to.
    /// A background loop will receive and handle them.
    pub(crate) sender: Sender<DebugEventLogData>,
}

impl DebugLogging {
    pub(crate) fn log_event(&self, event: EventType) {
        let event_data = DebugEventLogData {
            time: time(),
            msg_id: self.msg_id,
            event,
        };

        self.sender.try_send(event_data).ok();
    }
}

/// Store all information needed to log an event to a webxdc.
pub struct DebugEventLogData {
    pub time: i64,
    pub msg_id: MsgId,
    pub event: EventType,
}

/// Creates a loop which forwards all log messages send into the channel to the associated
/// logging xdc.
pub async fn debug_logging_loop(context: &Context, events: Receiver<DebugEventLogData>) {
    while let Ok(DebugEventLogData {
        time,
        msg_id,
        event,
    }) = events.recv().await
    {
        match context
            .write_status_update_inner(
                &msg_id,
                &StatusUpdateItem {
                    payload: json!({
                        "event": event,
                        "time": time,
                    }),
                    info: None,
                    href: None,
                    summary: None,
                    document: None,
                    uid: None,
                    notify: None,
                },
                time,
            )
            .await
        {
            Err(err) => {
                eprintln!("Can't log event to webxdc status update: {err:#}");
            }
            Ok(serial) => {
                if let Some(serial) = serial {
                    if !matches!(event, EventType::WebxdcStatusUpdate { .. }) {
                        context.emit_event(EventType::WebxdcStatusUpdate {
                            msg_id,
                            status_update_serial: serial,
                        });
                    }
                } else {
                    // This should not happen as the update has no `uid`.
                    error!(context, "Debug logging update is not created.");
                };
            }
        }
    }
}

/// Set message as new logging webxdc if filename and chat_id fit
pub async fn maybe_set_logging_xdc(
    context: &Context,
    msg: &Message,
    chat_id: ChatId,
) -> anyhow::Result<()> {
    maybe_set_logging_xdc_inner(
        context,
        msg.get_viewtype(),
        chat_id,
        msg.param.get(Param::Filename),
        msg.get_id(),
    )
    .await?;

    Ok(())
}

/// Set message as new logging webxdc if filename and chat_id fit
pub async fn maybe_set_logging_xdc_inner(
    context: &Context,
    viewtype: Viewtype,
    chat_id: ChatId,
    filename: Option<&str>,
    msg_id: MsgId,
) -> anyhow::Result<()> {
    if viewtype == Viewtype::Webxdc
        && let Some(filename) = filename
        && filename.starts_with("debug_logging")
        && filename.ends_with(".xdc")
        && chat_id.is_self_talk(context).await?
    {
        set_debug_logging_xdc(context, Some(msg_id)).await?;
    }
    Ok(())
}

/// Set the webxdc contained in the msg as the current logging xdc on the context and save it to db
/// If id is a `None` value, disable debug logging
pub(crate) async fn set_debug_logging_xdc(ctx: &Context, id: Option<MsgId>) -> anyhow::Result<()> {
    match id {
        Some(msg_id) => {
            ctx.sql
                .set_raw_config(
                    Config::DebugLogging.as_ref(),
                    Some(msg_id.to_string().as_ref()),
                )
                .await?;
            {
                let debug_logging = &mut *ctx.debug_logging.write().expect("RwLock is poisoned");
                match debug_logging {
                    // Switch logging xdc
                    Some(debug_logging) => debug_logging.msg_id = msg_id,
                    // Bootstrap background loop for message forwarding
                    None => {
                        let (sender, debug_logging_recv) = channel::bounded(1000);
                        let loop_handle = {
                            let ctx = ctx.clone();
                            task::spawn(async move {
                                debug_logging_loop(&ctx, debug_logging_recv).await
                            })
                        };
                        *debug_logging = Some(DebugLogging {
                            msg_id,
                            loop_handle,
                            sender,
                        });
                    }
                }
            }
            info!(ctx, "replacing logging webxdc");
        }
        // Delete current debug logging
        None => {
            ctx.sql
                .set_raw_config(Config::DebugLogging.as_ref(), None)
                .await?;
            *ctx.debug_logging.write().expect("RwLock is poisoned") = None;
            info!(ctx, "removing logging webxdc");
        }
    }
    Ok(())
}