ftth-rsipstack 4.0.3

use super::dialog::{Dialog, DialogInnerRef, DialogState, TerminatedReason};
use super::DialogId;
use crate::dialog::dialog::DialogInner;
use crate::rsip;
use crate::transport::SipConnection;
use crate::{
    transaction::transaction::{Transaction, TransactionEvent},
    Result,
};
use rsip::{prelude::HeadersExt, Header, Request, SipMessage, StatusCode};
use std::sync::atomic::Ordering;
use tokio_util::sync::CancellationToken;
use tracing::{debug, info, trace, warn};

/// Server-side INVITE Dialog (UAS)
///
/// `ServerInviteDialog` represents a server-side INVITE dialog in SIP. This is used
/// when the local user agent acts as a User Agent Server (UAS) and receives
/// an INVITE transaction from a remote party to establish a session.
///
/// # Key Features
///
/// * **Session Acceptance** - Accepts or rejects incoming INVITE requests
/// * **In-dialog Requests** - Handles UPDATE, INFO, OPTIONS within established dialogs
/// * **Session Termination** - Handles BYE for ending sessions
/// * **Re-INVITE Support** - Supports session modification via re-INVITE
/// * **ACK Handling** - Properly handles ACK for 2xx responses
/// * **State Management** - Tracks dialog state transitions
///
/// # Dialog Lifecycle
///
/// 1. **Creation** - Dialog created when receiving INVITE
/// 2. **Processing** - Can send provisional responses (1xx)
/// 3. **Decision** - Accept (2xx) or reject (3xx-6xx) the INVITE
/// 4. **Wait ACK** - If accepted, wait for ACK from client
/// 5. **Confirmed** - ACK received, dialog established
/// 6. **Active** - Can handle in-dialog requests
/// 7. **Termination** - Receives BYE or sends BYE to end session
///
/// # Examples
///
/// ## Basic Call Handling
///
/// ```rust,no_run
/// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
/// # fn example() -> ftth_rsipstack::Result<()> {
/// # let dialog: ServerInviteDialog = todo!(); // Dialog is typically created by DialogLayer
/// # let answer_sdp = vec![];
/// // After receiving INVITE:
///
/// // Accept the call
/// dialog.accept(None, Some(answer_sdp))?;
///
/// // Or reject the call
/// dialog.reject(None, None)?;
/// # Ok(())
/// # }
/// ```
///
/// ```rust,no_run
/// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
/// # async fn example() -> ftth_rsipstack::Result<()> {
/// # let dialog: ServerInviteDialog = todo!();
/// // End an established call
/// dialog.bye().await?;
/// # Ok(())
/// # }
/// ```
///
/// ## Session Modification
///
/// ```rust,no_run
/// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
/// # async fn example() -> ftth_rsipstack::Result<()> {
/// # let dialog: ServerInviteDialog = todo!();
/// # let new_sdp = vec![];
/// // Send re-INVITE to modify session
/// let headers = vec![
///     rsip::Header::ContentType("application/sdp".into())
/// ];
/// let response = dialog.reinvite(Some(headers), Some(new_sdp)).await?;
/// # Ok(())
/// # }
/// ```
///
/// # Thread Safety
///
/// ServerInviteDialog is thread-safe and can be cloned and shared across tasks.
/// All operations are atomic and properly synchronized.
#[derive(Clone)]
pub struct ServerInviteDialog {
    pub(super) inner: DialogInnerRef,
}

impl ServerInviteDialog {
    /// Get the dialog identifier
    ///
    /// Returns the unique DialogId that identifies this dialog instance.
    /// The DialogId consists of Call-ID, from-tag, and to-tag.
    pub fn id(&self) -> DialogId {
        self.inner.id.lock().unwrap().clone()
    }

    pub fn state(&self) -> DialogState {
        self.inner.state.lock().unwrap().clone()
    }

    /// Get the cancellation token for this dialog
    ///
    /// Returns a reference to the CancellationToken that can be used to
    /// cancel ongoing operations for this dialog.
    pub fn cancel_token(&self) -> &CancellationToken {
        &self.inner.cancel_token
    }

    /// Get the initial INVITE request
    ///
    /// Returns a reference to the initial INVITE request that created
    /// this dialog. This can be used to access the original request
    /// headers, body, and other information.
    pub fn initial_request(&self) -> &Request {
        &self.inner.initial_request
    }

    pub fn ringing(&self, headers: Option<Vec<Header>>, body: Option<Vec<u8>>) -> Result<()> {
        if !self.inner.can_cancel() {
            return Ok(());
        }
        info!(id = %self.id(), "sending ringing response");
        let resp = self.inner.make_response(
            &self.inner.initial_request,
            if body.is_some() {
                StatusCode::SessionProgress
            } else {
                StatusCode::Ringing
            },
            headers,
            body,
        );
        self.inner
            .tu_sender
            .send(TransactionEvent::Respond(resp.clone()))?;
        self.inner.transition(DialogState::Early(self.id(), resp))?;
        Ok(())
    }
    /// Accept the incoming INVITE request
    ///
    /// Sends a 200 OK response to accept the incoming INVITE request.
    /// This establishes the dialog and transitions it to the WaitAck state,
    /// waiting for the ACK from the client.
    ///
    /// # Parameters
    ///
    /// * `headers` - Optional additional headers to include in the response
    /// * `body` - Optional message body (typically SDP answer)
    ///
    /// # Returns
    ///
    /// * `Ok(())` - Response sent successfully
    /// * `Err(Error)` - Failed to send response or transaction terminated
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// // Accept with SDP answer
    /// let answer_sdp = b"v=0\r\no=- 123 456 IN IP4 192.168.1.1\r\n...";
    /// let headers = vec![
    ///     rsip::Header::ContentType("application/sdp".into())
    /// ];
    /// dialog.accept(Some(headers), Some(answer_sdp.to_vec()))?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn accept(&self, headers: Option<Vec<Header>>, body: Option<Vec<u8>>) -> Result<()> {
        let resp = self.inner.make_response(
            &self.inner.initial_request,
            rsip::StatusCode::OK,
            headers,
            body,
        );
        let via = self.inner.initial_request.via_header()?;
        let (via_transport, via_received) = SipConnection::parse_target_from_via(via)?;
        let mut params = vec![];
        if via_transport != rsip::transport::Transport::Udp {
            params.push(rsip::param::Param::Transport(via_transport));
        }
        let contact = rsip::headers::typed::Contact {
            uri: rsip::Uri {
                host_with_port: via_received,
                params,
                ..Default::default()
            },
            display_name: None,
            params: vec![],
        };
        debug!(id = %self.id(), "accepting dialog with contact: {}", contact);
        self.inner
            .remote_contact
            .lock()
            .unwrap()
            .replace(contact.untyped());
        self.inner
            .tu_sender
            .send(TransactionEvent::Respond(resp.clone()))?;

        self.inner
            .transition(DialogState::WaitAck(self.id(), resp))?;
        Ok(())
    }

    /// Accept the incoming INVITE request with NAT-aware Contact header
    ///
    /// Sends a 200 OK response to accept the incoming INVITE request, automatically
    /// adding a Contact header with the provided public address for proper NAT traversal.
    /// This is the recommended method when working with NAT environments.
    ///
    /// # Parameters
    ///
    /// * `username` - SIP username for the Contact header
    /// * `public_address` - Optional public address discovered via registration
    /// * `local_address` - Local SIP address as fallback
    /// * `headers` - Optional additional headers to include
    /// * `body` - Optional SDP answer body
    ///
    /// # Returns
    ///
    /// * `Ok(())` - Response sent successfully
    /// * `Err(Error)` - Failed to send response or transaction terminated
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # use ftth_rsipstack::transport::SipAddr;
    /// # use std::net::{IpAddr, Ipv4Addr};
    /// # fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// # let local_addr: SipAddr = todo!();
    /// let public_addr = Some(rsip::HostWithPort {
    ///     host: IpAddr::V4(Ipv4Addr::new(203, 0, 113, 1)).into(),
    ///     port: Some(5060.into()),
    /// });
    /// let answer_sdp = b"v=0\r\no=- 123 456 IN IP4 203.0.113.1\r\n...";
    /// let headers = vec![
    ///     rsip::Header::ContentType("application/sdp".into())
    /// ];
    ///
    /// dialog.accept_with_public_contact(
    ///     "alice",
    ///     public_addr,
    ///     &local_addr,
    ///     Some(headers),
    ///     Some(answer_sdp.to_vec())
    /// )?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn accept_with_public_contact(
        &self,
        username: &str,
        public_address: Option<rsip::HostWithPort>,
        local_address: &crate::transport::SipAddr,
        headers: Option<Vec<Header>>,
        body: Option<Vec<u8>>,
    ) -> Result<()> {
        use super::registration::Registration;

        // Create NAT-aware Contact header
        let contact_header =
            Registration::create_nat_aware_contact(username, public_address, local_address);

        // Combine provided headers with Contact header
        let mut final_headers = headers.unwrap_or_default();
        final_headers.push(contact_header.into());

        // Use the regular accept method with the enhanced headers
        self.accept(Some(final_headers), body)
    }

    /// Reject the incoming INVITE request
    ///
    /// Sends a reject response to reject the incoming INVITE request.
    /// Sends a 603 Decline by default, or a custom status code if provided.
    /// This terminates the dialog creation process.
    ///
    /// # Returns
    ///
    /// * `Ok(())` - Response sent successfully
    /// * `Err(Error)` - Failed to send response or transaction terminated
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// // Reject the incoming call
    /// dialog.reject(Some(rsip::StatusCode::BusyHere), Some("Busy here".into()))?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn reject(&self, code: Option<rsip::StatusCode>, reason: Option<String>) -> Result<()> {
        if self.inner.is_terminated() || self.inner.is_confirmed() {
            return Ok(());
        }
        info!(id=%self.id(), ?code, ?reason, "rejecting dialog");
        let headers = if let Some(reason) = reason {
            Some(vec![rsip::Header::Other("Reason".into(), reason.into())])
        } else {
            None
        };
        let resp = self.inner.make_response(
            &self.inner.initial_request,
            code.unwrap_or(rsip::StatusCode::Decline),
            headers,
            None,
        );
        self.inner
            .tu_sender
            .send(TransactionEvent::Respond(resp))
            .ok();
        self.inner.transition(DialogState::Terminated(
            self.id(),
            TerminatedReason::UasDecline,
        ))
    }

    /// Send a BYE request to terminate the dialog
    ///
    /// Sends a BYE request to gracefully terminate an established dialog.
    /// This should only be called for confirmed dialogs. If the dialog
    /// is not confirmed, this method returns immediately without error.
    ///
    /// # Returns
    ///
    /// * `Ok(())` - BYE was sent successfully or dialog not confirmed
    /// * `Err(Error)` - Failed to send BYE request
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # async fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// // End an established call
    /// dialog.bye().await?;
    /// # Ok(())
    /// # }
    /// ```
    pub async fn bye(&self) -> Result<()> {
        if !self.inner.is_confirmed() {
            return Ok(());
        }
        info!(id=%self.id(), "sending bye request");

        let request = self.inner.make_request_with_vias(
            rsip::Method::Bye,
            None,
            self.inner.build_vias_from_request()?,
            None,
            None,
        )?;

        match self.inner.do_request(request).await {
            Ok(_) => {}
            Err(e) => {
                info!(id=%self.id(),"bye error: {}", e);
            }
        };
        self.inner
            .transition(DialogState::Terminated(self.id(), TerminatedReason::UasBye))?;
        Ok(())
    }

    /// Send a re-INVITE request to modify the session
    ///
    /// Sends a re-INVITE request within an established dialog to modify
    /// the session parameters (e.g., change media, add/remove streams).
    /// This can only be called for confirmed dialogs.
    ///
    /// # Parameters
    ///
    /// * `headers` - Optional additional headers to include
    /// * `body` - Optional message body (typically new SDP)
    ///
    /// # Returns
    ///
    /// * `Ok(Some(Response))` - Response to the re-INVITE
    /// * `Ok(None)` - Dialog not confirmed, no request sent
    /// * `Err(Error)` - Failed to send re-INVITE
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # async fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// let new_sdp = b"v=0\r\no=- 123 456 IN IP4 192.168.1.1\r\n...";
    /// let response = dialog.reinvite(None, Some(new_sdp.to_vec())).await?;
    /// # Ok(())
    /// # }
    /// ```
    pub async fn reinvite(
        &self,
        headers: Option<Vec<rsip::Header>>,
        body: Option<Vec<u8>>,
    ) -> Result<Option<rsip::Response>> {
        if !self.inner.is_confirmed() {
            return Ok(None);
        }
        info!(id=%self.id(), "sending re-invite request, body: \n{:?}", body);
        let request = self.inner.make_request_with_vias(
            rsip::Method::Invite,
            None,
            self.inner.build_vias_from_request()?,
            headers,
            body,
        )?;
        let resp = self.inner.do_request(request.clone()).await;
        match resp {
            Ok(Some(ref resp)) => {
                if resp.status_code == StatusCode::OK {
                    self.inner
                        .transition(DialogState::Updated(self.id(), request))?;
                }
            }
            _ => {}
        }
        resp
    }

    /// Send an UPDATE request to modify session parameters
    ///
    /// Sends an UPDATE request within an established dialog to modify
    /// session parameters without the complexity of a re-INVITE.
    /// This is typically used for smaller session modifications.
    ///
    /// # Parameters
    ///
    /// * `headers` - Optional additional headers to include
    /// * `body` - Optional message body (typically SDP)
    ///
    /// # Returns
    ///
    /// * `Ok(Some(Response))` - Response to the UPDATE
    /// * `Ok(None)` - Dialog not confirmed, no request sent
    /// * `Err(Error)` - Failed to send UPDATE
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # async fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// # let sdp_body = vec![];
    /// let response = dialog.update(None, Some(sdp_body)).await?;
    /// # Ok(())
    /// # }
    /// ```
    pub async fn update(
        &self,
        headers: Option<Vec<rsip::Header>>,
        body: Option<Vec<u8>>,
    ) -> Result<Option<rsip::Response>> {
        if !self.inner.is_confirmed() {
            return Ok(None);
        }
        info!(id=%self.id(), "sending update request, body: \n{:?}", body);
        let request = self.inner.make_request_with_vias(
            rsip::Method::Update,
            None,
            self.inner.build_vias_from_request()?,
            headers,
            body,
        )?;
        self.inner.do_request(request.clone()).await
    }

    /// Send an INFO request for mid-dialog information
    ///
    /// Sends an INFO request within an established dialog to exchange
    /// application-level information. This is commonly used for DTMF
    /// tones, but can carry any application-specific data.
    ///
    /// # Parameters
    ///
    /// * `headers` - Optional additional headers to include
    /// * `body` - Optional message body (application-specific data)
    ///
    /// # Returns
    ///
    /// * `Ok(Some(Response))` - Response to the INFO
    /// * `Ok(None)` - Dialog not confirmed, no request sent
    /// * `Err(Error)` - Failed to send INFO
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use ftth_rsipstack::dialog::server_dialog::ServerInviteDialog;
    /// # async fn example() -> ftth_rsipstack::Result<()> {
    /// # let dialog: ServerInviteDialog = todo!();
    /// // Send DTMF tone
    /// let dtmf_body = b"Signal=1\r\nDuration=100\r\n";
    /// let headers = vec![
    ///     rsip::Header::ContentType("application/dtmf-relay".into())
    /// ];
    /// let response = dialog.info(Some(headers), Some(dtmf_body.to_vec())).await?;
    /// # Ok(())
    /// # }
    /// ```
    pub async fn info(
        &self,
        headers: Option<Vec<rsip::Header>>,
        body: Option<Vec<u8>>,
    ) -> Result<Option<rsip::Response>> {
        if !self.inner.is_confirmed() {
            return Ok(None);
        }
        info!(id=%self.id(), "sending info request, body: \n{:?}", body);
        let request = self.inner.make_request_with_vias(
            rsip::Method::Info,
            None,
            self.inner.build_vias_from_request()?,
            headers,
            body,
        )?;
        self.inner.do_request(request.clone()).await
    }

    /// Handle incoming transaction for this dialog
    ///
    /// Processes incoming SIP requests that are routed to this dialog.
    /// This method handles sequence number validation and dispatches
    /// to appropriate handlers based on the request method and dialog state.
    ///
    /// # Parameters
    ///
    /// * `tx` - The incoming transaction to handle
    ///
    /// # Returns
    ///
    /// * `Ok(())` - Request handled successfully
    /// * `Err(Error)` - Failed to handle request
    ///
    /// # Supported Methods
    ///
    /// * `ACK` - Confirms 2xx response (transitions to Confirmed state)
    /// * `BYE` - Terminates the dialog
    /// * `INFO` - Handles information exchange
    /// * `OPTIONS` - Handles capability queries
    /// * `UPDATE` - Handles session updates
    /// * `INVITE` - Handles initial INVITE or re-INVITE
    pub async fn handle(&mut self, tx: &mut Transaction) -> Result<()> {
        debug!(
            id = %self.id(),
            "handle request: {} state:{}",
            tx.original,
            self.inner.state.lock().unwrap()
        );

        let cseq = tx.original.cseq_header()?.seq()?;
        let remote_seq = self.inner.remote_seq.load(Ordering::Relaxed);
        if remote_seq > 0 && cseq < remote_seq {
            info!(
                id=%self.id(),
                "received old request {} remote_seq: {} > {}",
                tx.original.method(),
                remote_seq,
                cseq
            );
            // discard old request
            return Ok(());
        }

        self.inner
            .remote_seq
            .compare_exchange(remote_seq, cseq, Ordering::Relaxed, Ordering::Relaxed)
            .ok();

        if self.inner.is_confirmed() {
            match tx.original.method {
                rsip::Method::Cancel => {
                    info!(id=%self.id(),
                        "invalid request received {} {}",
                        tx.original.method, tx.original.uri
                    );
                    tx.reply(rsip::StatusCode::OK).await?;
                    return Ok(());
                }
                rsip::Method::Invite | rsip::Method::Ack => {
                    info!(id=%self.id(),
                        "invalid request received {} {}",
                        tx.original.method, tx.original.uri
                    );
                    return Err(crate::Error::DialogError(
                        "invalid request in confirmed state".to_string(),
                        self.id(),
                        rsip::StatusCode::MethodNotAllowed,
                    ));
                }
                rsip::Method::Bye => return self.handle_bye(tx).await,
                rsip::Method::Info => return self.handle_info(tx).await,
                rsip::Method::Options => return self.handle_options(tx).await,
                rsip::Method::Update => return self.handle_update(tx).await,
                _ => {
                    info!(id=%self.id(),"invalid request method: {:?}", tx.original.method);
                    tx.reply(rsip::StatusCode::MethodNotAllowed).await?;
                    return Err(crate::Error::DialogError(
                        "invalid request".to_string(),
                        self.id(),
                        rsip::StatusCode::MethodNotAllowed,
                    ));
                }
            }
        } else {
            match tx.original.method {
                rsip::Method::Ack => {
                    self.inner.tu_sender.send(TransactionEvent::Received(
                        tx.original.clone().into(),
                        tx.connection.clone(),
                    ))?;
                }
                _ => {}
            }
        }
        self.handle_invite(tx).await
    }

    async fn handle_bye(&mut self, tx: &mut Transaction) -> Result<()> {
        info!(id = %self.id(), "received bye {}", tx.original.uri);
        self.inner
            .transition(DialogState::Terminated(self.id(), TerminatedReason::UacBye))?;
        tx.reply(rsip::StatusCode::OK).await?;
        Ok(())
    }

    async fn handle_info(&mut self, tx: &mut Transaction) -> Result<()> {
        info!(id = %self.id(), "received info {}", tx.original.uri);
        self.inner
            .transition(DialogState::Info(self.id(), tx.original.clone()))?;
        tx.reply(rsip::StatusCode::OK).await?;
        Ok(())
    }

    async fn handle_options(&mut self, tx: &mut Transaction) -> Result<()> {
        info!(id = %self.id(), "received options {}", tx.original.uri);
        self.inner
            .transition(DialogState::Options(self.id(), tx.original.clone()))?;
        tx.reply(rsip::StatusCode::OK).await?;
        Ok(())
    }

    async fn handle_update(&mut self, tx: &mut Transaction) -> Result<()> {
        info!(id = %self.id(), "received update {}", tx.original.uri);
        self.inner
            .transition(DialogState::Updated(self.id(), tx.original.clone()))?;
        tx.reply(rsip::StatusCode::OK).await?;
        Ok(())
    }

    async fn handle_invite(&mut self, tx: &mut Transaction) -> Result<()> {
        let handle_loop = async {
            if !self.inner.is_confirmed() && matches!(tx.original.method, rsip::Method::Invite) {
                match self.inner.transition(DialogState::Calling(self.id())) {
                    Ok(_) => {
                        tx.send_trying().await.ok();
                    }
                    Err(_) => {}
                }
            }

            while let Some(msg) = tx.receive().await {
                match msg {
                    SipMessage::Request(req) => match req.method {
                        rsip::Method::Ack => {
                            if self.inner.is_terminated() {
                                // dialog already terminated, ignore
                                break;
                            }
                            info!(id = %self.id(),"received ack {}", req.uri);
                            match req.contact_header() {
                                Ok(contact) => {
                                    self.inner
                                        .remote_contact
                                        .lock()
                                        .unwrap()
                                        .replace(contact.clone());
                                }
                                _ => {}
                            }

                            self.inner.transition(DialogState::Confirmed(
                                self.id(),
                                tx.last_response.clone().unwrap_or_default(),
                            ))?;
                            DialogInner::serve_keepalive_options(self.inner.clone());
                            break;
                        }
                        rsip::Method::Cancel => {
                            info!(id = %self.id(),"received cancel {}", req.uri);
                            tx.reply(rsip::StatusCode::RequestTerminated).await?;
                            self.inner.transition(DialogState::Terminated(
                                self.id(),
                                TerminatedReason::UacCancel,
                            ))?;
                        }
                        _ => {}
                    },
                    SipMessage::Response(_) => {}
                }
            }
            Ok::<(), crate::Error>(())
        };
        match handle_loop.await {
            Ok(_) => {
                trace!(id = %self.id(),"process done");
                Ok(())
            }
            Err(e) => {
                warn!(id = %self.id(),"handle_invite error: {:?}", e);
                Err(e)
            }
        }
    }
}

impl TryFrom<&Dialog> for ServerInviteDialog {
    type Error = crate::Error;

    fn try_from(dlg: &Dialog) -> Result<Self> {
        match dlg {
            Dialog::ServerInvite(dlg) => Ok(dlg.clone()),
            _ => Err(crate::Error::DialogError(
                "Dialog is not a ServerInviteDialog".to_string(),
                dlg.id(),
                rsip::StatusCode::BadRequest,
            )),
        }
    }
}