//! Call hub — owns N legs and a mixer task.
//!
//! Every call has a central mixer that provides mix-minus audio to all
//! participants. Legs can be added and removed dynamically mid-call.

use crate::mixer::{MixerCommand, RtpPacket};
use crate::sip_leg::SipLeg;
use std::collections::HashMap;
use std::net::SocketAddr;
use std::sync::Arc;
use std::time::Instant;
use tokio::net::UdpSocket;
use tokio::sync::mpsc;
use tokio::task::JoinHandle;

pub type LegId = String;

/// Call state machine.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CallState {
    SettingUp,
    Ringing,
    Connected,
    Voicemail,
    Terminated,
}

impl CallState {
    pub fn as_str(&self) -> &'static str {
        match self {
            Self::SettingUp => "setting-up",
            Self::Ringing => "ringing",
            Self::Connected => "connected",
            Self::Voicemail => "voicemail",
            Self::Terminated => "terminated",
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CallDirection {
    Inbound,
    Outbound,
}

impl CallDirection {
    pub fn as_str(&self) -> &'static str {
        match self {
            Self::Inbound => "inbound",
            Self::Outbound => "outbound",
        }
    }
}

/// The type of a call leg.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum LegKind {
    SipProvider,
    SipDevice,
    WebRtc,
    Media, // voicemail playback, IVR, recording
}

impl LegKind {
    pub fn as_str(&self) -> &'static str {
        match self {
            Self::SipProvider => "sip-provider",
            Self::SipDevice => "sip-device",
            Self::WebRtc => "webrtc",
            Self::Media => "media",
        }
    }
}

/// Per-leg state.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum LegState {
    Inviting,
    Ringing,
    Connected,
    Terminated,
}

impl LegState {
    pub fn as_str(&self) -> &'static str {
        match self {
            Self::Inviting => "inviting",
            Self::Ringing => "ringing",
            Self::Connected => "connected",
            Self::Terminated => "terminated",
        }
    }
}

/// Information about a single leg in a call.
pub struct LegInfo {
    pub id: LegId,
    pub kind: LegKind,
    pub state: LegState,
    pub codec_pt: u8,

    /// For SIP legs: the SIP dialog manager (handles 407 auth, BYE, etc).
    pub sip_leg: Option<SipLeg>,
    /// For SIP legs: the SIP Call-ID for message routing.
    pub sip_call_id: Option<String>,
    /// For WebRTC legs: the session ID in WebRtcEngine.
    pub webrtc_session_id: Option<String>,
    /// The RTP socket allocated for this leg.
    pub rtp_socket: Option<Arc<UdpSocket>>,
    /// The RTP port number.
    pub rtp_port: u16,
    /// The remote media endpoint (learned from SDP or address learning).
    pub remote_media: Option<SocketAddr>,
    /// SIP signaling address (provider or device).
    pub signaling_addr: Option<SocketAddr>,
}

/// A multiparty call with N legs and a central mixer.
pub struct Call {
    pub id: String,
    pub state: CallState,
    pub direction: CallDirection,
    pub created_at: Instant,

    // Metadata.
    pub caller_number: Option<String>,
    pub callee_number: Option<String>,
    pub provider_id: String,

    /// All legs in this call, keyed by leg ID.
    pub legs: HashMap<LegId, LegInfo>,

    /// Channel to send commands to the mixer task.
    pub mixer_cmd_tx: mpsc::Sender<MixerCommand>,

    /// Handle to the mixer task (aborted on call teardown).
    mixer_task: Option<JoinHandle<()>>,
}

impl Call {
    pub fn new(
        id: String,
        direction: CallDirection,
        provider_id: String,
        mixer_cmd_tx: mpsc::Sender<MixerCommand>,
        mixer_task: JoinHandle<()>,
    ) -> Self {
        Self {
            id,
            state: CallState::SettingUp,
            direction,
            created_at: Instant::now(),
            caller_number: None,
            callee_number: None,
            provider_id,
            legs: HashMap::new(),
            mixer_cmd_tx,
            mixer_task: Some(mixer_task),
        }
    }

    /// Add a leg to the mixer. Sends the AddLeg command with channel endpoints.
    pub async fn add_leg_to_mixer(
        &self,
        leg_id: &str,
        codec_pt: u8,
        inbound_rx: mpsc::Receiver<RtpPacket>,
        outbound_tx: mpsc::Sender<Vec<u8>>,
    ) {
        let _ = self
            .mixer_cmd_tx
            .send(MixerCommand::AddLeg {
                leg_id: leg_id.to_string(),
                codec_pt,
                inbound_rx,
                outbound_tx,
            })
            .await;
    }

    /// Remove a leg from the mixer.
    pub async fn remove_leg_from_mixer(&self, leg_id: &str) {
        let _ = self
            .mixer_cmd_tx
            .send(MixerCommand::RemoveLeg {
                leg_id: leg_id.to_string(),
            })
            .await;
    }

    pub fn duration_secs(&self) -> u64 {
        self.created_at.elapsed().as_secs()
    }

    /// Shut down the mixer and abort its task.
    pub async fn shutdown_mixer(&mut self) {
        let _ = self.mixer_cmd_tx.send(MixerCommand::Shutdown).await;
        if let Some(handle) = self.mixer_task.take() {
            handle.abort();
        }
    }

    /// Produce a JSON status snapshot for the dashboard.
    pub fn to_status_json(&self) -> serde_json::Value {
        let legs: Vec<serde_json::Value> = self
            .legs
            .values()
            .filter(|l| l.state != LegState::Terminated)
            .map(|l| {
                serde_json::json!({
                    "id": l.id,
                    "type": l.kind.as_str(),
                    "state": l.state.as_str(),
                    "codec": sip_proto::helpers::codec_name(l.codec_pt),
                    "rtpPort": l.rtp_port,
                    "remoteMedia": l.remote_media.map(|a| format!("{}:{}", a.ip(), a.port())),
                })
            })
            .collect();

        serde_json::json!({
            "id": self.id,
            "state": self.state.as_str(),
            "direction": self.direction.as_str(),
            "callerNumber": self.caller_number,
            "calleeNumber": self.callee_number,
            "providerUsed": self.provider_id,
            "duration": self.duration_secs(),
            "legs": legs,
        })
    }
}