freeswitch-log-parser 0.8.0

use std::collections::{HashMap, HashSet};
use std::str::FromStr;

use freeswitch_types::{BridgeDialString, CallDirection, DialString};

use crate::line::parse_line;
use crate::message::{classify_message, MessageKind};
use crate::stream::{Block, LogEntry, LogStream, ParseStats, UnclassifiedLine};

type SessionHook = Box<dyn Fn(&LogEntry, &mut SessionState) + Send>;

/// Mutable per-UUID state accumulator, updated as entries are processed.
///
/// Fields are `None` until the corresponding data is first seen in the stream.
/// Variables accumulate from CHANNEL_DATA dumps, `set()`/`export()` executions,
/// `SET`/`EXPORT` log lines, and inline `variable_*` lines.
#[derive(Debug, Clone, Default)]
pub struct SessionState {
    /// `None` until a `Channel-Name` field is encountered.
    pub channel_name: Option<String>,
    /// `None` until a state change or `Channel-State` field is encountered.
    pub channel_state: Option<String>,
    /// First dialplan context seen; set once and never overwritten.
    pub initial_context: Option<String>,
    /// Destination of the first `Processing` line = the dialed number at ingress;
    /// set once and never overwritten (unlike last-wins `dialplan_to`).
    pub initial_destination: Option<String>,
    /// Current dialplan context; updated on each transfer/continue.
    pub dialplan_context: Option<String>,
    /// Source extension in the dialplan routing; `None` until a dialplan line is processed.
    pub dialplan_from: Option<String>,
    /// Target extension in the dialplan routing; `None` until a dialplan line is processed.
    pub dialplan_to: Option<String>,
    /// Call direction from `Call-Direction` CHANNEL_DATA field; `None` until seen.
    pub call_direction: Option<CallDirection>,
    /// Caller ID number from `Caller-Caller-ID-Number` CHANNEL_DATA field; `None` until seen.
    pub caller_id_number: Option<String>,
    /// Caller ID name from `Caller-Caller-ID-Name` CHANNEL_DATA field; `None` until seen.
    pub caller_id_name: Option<String>,
    /// Destination number from `Caller-Destination-Number` CHANNEL_DATA field; `None` until seen.
    pub destination_number: Option<String>,
    /// Hangup cause extracted from ChannelLifecycle Hangup detail; `None` until hangup seen.
    pub hangup_cause: Option<String>,
    /// Timestamp when "has been answered" lifecycle event was seen; `None` until answered.
    pub answered_at: Option<String>,
    /// Other leg's UUID; `None` until bridged. Set from `Originate Resulted in Success` on A-leg,
    /// and from `New Channel` on B-leg (back-pointing to A-leg via originate context).
    pub other_leg_uuid: Option<String>,
    /// Pending bridge target channel from `EXECUTE bridge()`, consumed when B-leg `New Channel` matches.
    pub(crate) pending_bridge_target: Option<String>,
    /// All variables learned so far, with the `variable_` prefix stripped from names.
    pub variables: HashMap<String, String>,
}

/// Changes to indexed fields, diffed across hooks and built-in extraction
/// for index maintenance.
#[derive(Default)]
struct IndexedFieldChanges {
    channel_name: Option<(Option<String>, Option<String>)>,
    pending_bridge_target: Option<(Option<String>, Option<String>)>,
    other_leg_uuid: Option<(Option<String>, Option<String>)>,
}

impl IndexedFieldChanges {
    fn diff(
        old_channel_name: Option<String>,
        old_pending_bridge_target: Option<String>,
        old_other_leg_uuid: Option<String>,
        state: &SessionState,
    ) -> Self {
        let mut changes = IndexedFieldChanges::default();
        if state.channel_name != old_channel_name {
            changes.channel_name = Some((old_channel_name, state.channel_name.clone()));
        }
        if state.pending_bridge_target != old_pending_bridge_target {
            changes.pending_bridge_target = Some((
                old_pending_bridge_target,
                state.pending_bridge_target.clone(),
            ));
        }
        if state.other_leg_uuid != old_other_leg_uuid {
            changes.other_leg_uuid = Some((old_other_leg_uuid, state.other_leg_uuid.clone()));
        }
        changes
    }
}

/// Immutable point-in-time copy of a session's state, attached to each [`EnrichedEntry`].
///
/// Does not include `variables` to keep snapshots lightweight — access the full
/// variable map via [`SessionTracker::sessions()`].
#[derive(Debug, Clone)]
pub struct SessionSnapshot {
    pub channel_name: Option<String>,
    pub channel_state: Option<String>,
    pub initial_context: Option<String>,
    pub initial_destination: Option<String>,
    pub dialplan_context: Option<String>,
    pub dialplan_from: Option<String>,
    pub dialplan_to: Option<String>,
    pub call_direction: Option<CallDirection>,
    pub caller_id_number: Option<String>,
    pub caller_id_name: Option<String>,
    pub destination_number: Option<String>,
    pub hangup_cause: Option<String>,
    pub answered_at: Option<String>,
    pub other_leg_uuid: Option<String>,
}

impl SessionState {
    fn snapshot(&self) -> SessionSnapshot {
        SessionSnapshot {
            channel_name: self.channel_name.clone(),
            channel_state: self.channel_state.clone(),
            initial_context: self.initial_context.clone(),
            initial_destination: self.initial_destination.clone(),
            dialplan_context: self.dialplan_context.clone(),
            dialplan_from: self.dialplan_from.clone(),
            dialplan_to: self.dialplan_to.clone(),
            call_direction: self.call_direction,
            caller_id_number: self.caller_id_number.clone(),
            caller_id_name: self.caller_id_name.clone(),
            destination_number: self.destination_number.clone(),
            hangup_cause: self.hangup_cause.clone(),
            answered_at: self.answered_at.clone(),
            other_leg_uuid: self.other_leg_uuid.clone(),
        }
    }

    fn update_from_entry(&mut self, entry: &LogEntry) {
        let block_has_channel_data = matches!(entry.block, Some(Block::ChannelData { .. }));
        if let Some(Block::ChannelData { fields, variables }) = &entry.block {
            for (name, value) in fields {
                match name.as_str() {
                    "Channel-Name" => self.channel_name = Some(value.clone()),
                    "Channel-State" => self.channel_state = Some(value.clone()),
                    "Call-Direction" => {
                        self.call_direction = CallDirection::from_str(value).ok();
                    }
                    "Caller-Caller-ID-Number" => {
                        self.caller_id_number = Some(value.clone());
                    }
                    "Caller-Caller-ID-Name" => {
                        self.caller_id_name = Some(value.clone());
                    }
                    "Caller-Destination-Number" => {
                        self.destination_number = Some(value.clone());
                    }
                    "Other-Leg-Unique-ID" => {
                        self.other_leg_uuid = Some(value.clone());
                    }
                    _ => {}
                }
            }
            for (name, value) in variables {
                let var_name = name.strip_prefix("variable_").unwrap_or(name);
                self.variables.insert(var_name.to_string(), value.clone());
            }
        }

        match &entry.message_kind {
            MessageKind::Execute {
                application,
                arguments,
                ..
            } => match application.as_str() {
                "set" | "export" => {
                    if let Some((name, value)) = arguments.split_once('=') {
                        self.variables.insert(name.to_string(), value.to_string());
                    }
                }
                "bridge" => {
                    if let Some(info) = parse_bridge_args(arguments) {
                        if let Some(uuid) = &info.origination_uuid {
                            self.other_leg_uuid = Some(uuid.clone());
                        }
                        self.pending_bridge_target = Some(info.target_channel);
                    }
                }
                _ => {}
            },
            MessageKind::ChannelLifecycle { detail } => {
                if let Some(name) = parse_new_channel(detail) {
                    if self.channel_name.is_none() {
                        self.channel_name = Some(name);
                    }
                }
                if let Some(cause) = parse_hangup(detail) {
                    self.hangup_cause = Some(cause);
                }
                if is_answered(detail) && self.answered_at.is_none() {
                    self.answered_at = Some(entry.timestamp.clone());
                }
            }
            kind => self.apply_kind(kind),
        }

        self.apply_processing(&entry.message);

        for attached in &entry.attached {
            let parsed = parse_line(attached);
            self.update_from_message(parsed.message, block_has_channel_data);
        }
    }

    /// Canonical extraction for message kinds that appear on both primary and
    /// attached lines. Entry-only kinds (Execute, ChannelLifecycle — the
    /// latter needs the entry timestamp) stay in `update_from_entry`.
    fn apply_kind(&mut self, kind: &MessageKind) {
        match kind {
            MessageKind::Dialplan { detail, .. } => {
                if let Some(dp) = parse_dialplan_context(detail) {
                    self.initial_context.get_or_insert(dp.context.clone());
                    self.dialplan_context = Some(dp.context);
                    self.dialplan_from = Some(dp.from);
                    self.dialplan_to = Some(dp.to);
                }
            }
            MessageKind::Variable { name, value } => {
                let var_name = name.strip_prefix("variable_").unwrap_or(name);
                self.variables.insert(var_name.to_string(), value.clone());
            }
            MessageKind::ChannelField { name, value } => match name.as_str() {
                "Channel-Name" => self.channel_name = Some(value.clone()),
                "Channel-State" => self.channel_state = Some(value.clone()),
                _ => {}
            },
            MessageKind::StateChange { detail } => {
                if let Some(new_state) = parse_state_change(detail) {
                    self.channel_state = Some(new_state);
                }
            }
            _ => {}
        }
    }

    /// `Processing <caller>-><dest> in context <ctx>` — emitted by the dialplan
    /// hunt on both primary and attached lines; anchored on raw text because
    /// `classify_message` folds it into `Dialplan` with the prefix stripped.
    fn apply_processing(&mut self, msg: &str) {
        if msg.contains("Processing ") && msg.contains(" in context ") {
            if let Some(dp) = parse_processing_line(msg) {
                self.initial_context.get_or_insert(dp.context.clone());
                self.initial_destination.get_or_insert(dp.to.clone());
                self.dialplan_context = Some(dp.context);
                self.dialplan_from = Some(dp.from);
                self.dialplan_to = Some(dp.to);
            }
        }
    }

    fn update_from_message(&mut self, msg: &str, block_provides_channel_data: bool) {
        let kind = classify_message(msg);
        match &kind {
            // A ChannelData block already carries these — re-applying the raw
            // attached lines would clobber reassembled multi-line values with
            // their opening fragment.
            MessageKind::Variable { .. } | MessageKind::ChannelField { .. }
                if block_provides_channel_data => {}
            kind => self.apply_kind(kind),
        }
        self.apply_processing(msg);
    }
}

struct DialplanContext {
    from: String,
    to: String,
    context: String,
}

fn parse_dialplan_context(detail: &str) -> Option<DialplanContext> {
    if !detail.starts_with("parsing [") {
        return None;
    }
    let rest = &detail["parsing [".len()..];
    let bracket_end = rest.find(']')?;
    let inner = &rest[..bracket_end];

    let arrow = inner.find("->")?;
    let from_part = &inner[..arrow];
    let to_part = &inner[arrow + 2..];

    let context = if rest.len() > bracket_end + 1 {
        let after = rest[bracket_end + 1..].trim();
        if let Some(stripped) = after.strip_prefix("continue=") {
            let _ = stripped;
        }
        from_part.to_string()
    } else {
        from_part.to_string()
    };

    Some(DialplanContext {
        from: from_part.to_string(),
        to: to_part.to_string(),
        context,
    })
}

/// Parse `Processing <name> <<number>>-><dest> in context <ctx>`. Field 1 (caller_id_name) is
/// free-form and may contain spaces, `->`, `<`, so anchor on the fixed frame: the rightmost
/// ` in context ` and the last `>->` (the `>` closing `<number>` immediately precedes `->`, and
/// only the caller_id_number→destination boundary has that shape). Falls back to the last bare
/// `->` for the bracketless `from->to` shape.
fn parse_processing_line(msg: &str) -> Option<DialplanContext> {
    let proc_idx = msg.find("Processing ")?;
    let after_proc = &msg[proc_idx + "Processing ".len()..];

    let ctx_idx = after_proc.rfind(" in context ")?;
    let head = &after_proc[..ctx_idx];
    let context = after_proc[ctx_idx + " in context ".len()..]
        .split_whitespace()
        .next()?;

    let (from, to) = match head.rfind(">->") {
        Some(i) => (&head[..i + 1], &head[i + ">->".len()..]),
        None => {
            let i = head.rfind("->")?;
            (&head[..i], &head[i + "->".len()..])
        }
    };

    Some(DialplanContext {
        from: from.to_string(),
        to: to.to_string(),
        context: context.to_string(),
    })
}

fn parse_new_channel(detail: &str) -> Option<String> {
    let rest = detail.strip_prefix("New Channel ")?;
    let bracket = rest.rfind(" [")?;
    Some(rest[..bracket].to_string())
}

fn parse_state_change(detail: &str) -> Option<String> {
    let arrow = detail.find(" -> ")?;
    Some(detail[arrow + 4..].trim().to_string())
}

fn parse_hangup(detail: &str) -> Option<String> {
    if !detail.contains("Hangup ") {
        return None;
    }
    let start = detail.rfind('[')?;
    let end = detail[start..].find(']')?;
    Some(detail[start + 1..start + end].to_string())
}

fn is_answered(detail: &str) -> bool {
    detail.contains("has been answered")
}

/// Extract `origination_uuid` and the bridge target channel from bridge() arguments.
/// Uses `BridgeDialString` from freeswitch-types for correct parsing of `[]`, `{}`,
/// `|` failover, and `,` simultaneous ring syntax.
fn parse_bridge_args(arguments: &str) -> Option<BridgeInfo> {
    let dial = BridgeDialString::from_str(arguments).ok()?;
    let first_ep = dial.groups().first()?.first()?;
    let origination_uuid = first_ep
        .variables()
        .and_then(|v| v.get("origination_uuid"))
        .map(|s| s.to_string());
    let mut bare = first_ep.clone();
    bare.set_variables(None);
    let target_channel = bare.to_string();
    Some(BridgeInfo {
        origination_uuid,
        target_channel,
    })
}

struct BridgeInfo {
    origination_uuid: Option<String>,
    target_channel: String,
}

/// Parse "Originate Resulted in Success: [channel] Peer UUID: uuid"
fn parse_originate_success(msg: &str) -> Option<String> {
    let marker = "Peer UUID: ";
    let idx = msg.find(marker)?;
    let uuid = msg[idx + marker.len()..].trim();
    if uuid.is_empty() {
        None
    } else {
        Some(uuid.to_string())
    }
}

/// Parse the bracketed channel name from "Originate Resulted in Success: [<chan>] …".
/// Used as a fallback when the `Peer UUID:` suffix is absent (FS 1.10.5-dev and
/// similar builds). Returns the channel name borrowed from `msg`.
fn parse_originate_channel(msg: &str) -> Option<&str> {
    let start = msg.find(" [")? + 2;
    let end = msg[start..].find(']')?;
    let chan = &msg[start..start + end];
    if chan.is_empty() {
        None
    } else {
        Some(chan)
    }
}

/// Terminal channel-/callstate values — sessions left in one of these are
/// stragglers from prior calls and must not be considered candidates when
/// disambiguating channel-name collisions in the originate-success fallback.
///
/// Covers both `Channel-State` (`CS_*`) and `Callstate` (`HANGUP`). `DOWN` is
/// excluded because it doubles as the initial Callstate before any change is
/// observed.
fn is_terminal_channel_state(state: Option<&str>) -> bool {
    matches!(
        state,
        Some("CS_HANGUP" | "CS_REPORTING" | "CS_DESTROY" | "CS_NONE" | "HANGUP")
    )
}

/// A [`LogEntry`] paired with the session's state snapshot at that point in time.
#[derive(Debug)]
pub struct EnrichedEntry {
    pub entry: LogEntry,
    /// `None` for system lines (entries with an empty UUID).
    pub session: Option<SessionSnapshot>,
}

/// Layer 3 per-session state machine — tracks per-UUID state (dialplan context,
/// channel state, variables) across entries and yields [`EnrichedEntry`] values.
///
/// Wraps a [`LogStream`] and maintains a `HashMap<String, SessionState>` keyed by UUID.
/// Sessions are never automatically cleaned up; call [`remove_session()`](SessionTracker::remove_session)
/// when a call ends.
pub struct SessionTracker<I> {
    inner: LogStream<I>,
    sessions: HashMap<String, SessionState>,
    by_channel_name: HashMap<String, HashSet<String>>,
    by_pending_target: HashMap<String, String>,
    by_other_leg: HashMap<String, String>,
    pre_hook: Option<SessionHook>,
    post_hook: Option<SessionHook>,
}

impl<I: Iterator<Item = String>> SessionTracker<I> {
    /// Wrap a [`LogStream`] to add per-session state tracking.
    pub fn new(inner: LogStream<I>) -> Self {
        SessionTracker {
            inner,
            sessions: HashMap::new(),
            by_channel_name: HashMap::new(),
            by_pending_target: HashMap::new(),
            by_other_leg: HashMap::new(),
            pre_hook: None,
            post_hook: None,
        }
    }

    /// Register a hook that runs BEFORE built-in field extraction.
    ///
    /// Use this to override how specific fields are extracted. Fields set
    /// by the pre-hook may be preserved by built-in extraction if it uses
    /// `is_none()` guards. Indexed fields set by the hook (`channel_name`,
    /// `other_leg_uuid`) feed cross-session leg correlation like built-in
    /// extraction does.
    pub fn with_pre_hook<F>(mut self, hook: F) -> Self
    where
        F: Fn(&LogEntry, &mut SessionState) + Send + 'static,
    {
        self.pre_hook = Some(Box::new(hook));
        self
    }

    /// Register a hook that runs AFTER all built-in processing.
    ///
    /// Use this for custom field extraction and relationship detection.
    /// The hook can read fields populated by built-in extraction and
    /// fill gaps with application-specific patterns (e.g., `uuid_bridge`
    /// API results, custom SIP headers). Indexed fields set by the hook
    /// (`channel_name`, `other_leg_uuid`) feed cross-session leg
    /// correlation like built-in extraction does.
    ///
    /// # Example
    ///
    /// ```
    /// use freeswitch_log_parser::{LogStream, SessionTracker, MessageKind};
    ///
    /// let stream = LogStream::new(std::iter::empty::<String>());
    /// let tracker = SessionTracker::new(stream)
    ///     .with_post_hook(|entry, state| {
    ///         if let MessageKind::Execute { application, arguments, .. } = &entry.message_kind {
    ///             if application == "set" && arguments.starts_with("api_result=+OK ") {
    ///                 // extract UUID and set state.other_leg_uuid
    ///             }
    ///         }
    ///     });
    /// ```
    pub fn with_post_hook<F>(mut self, hook: F) -> Self
    where
        F: Fn(&LogEntry, &mut SessionState) + Send + 'static,
    {
        self.post_hook = Some(Box::new(hook));
        self
    }

    /// All currently tracked sessions, keyed by UUID.
    pub fn sessions(&self) -> &HashMap<String, SessionState> {
        &self.sessions
    }

    /// Remove and return a session's accumulated state. Call this when a call ends
    /// (e.g. `CS_DESTROY` or hangup) to free memory.
    pub fn remove_session(&mut self, uuid: &str) -> Option<SessionState> {
        let state = self.sessions.remove(uuid)?;
        if let Some(chan) = &state.channel_name {
            if let Some(set) = self.by_channel_name.get_mut(chan) {
                set.remove(uuid);
                if set.is_empty() {
                    self.by_channel_name.remove(chan);
                }
            }
        }
        if let Some(target) = &state.pending_bridge_target {
            self.by_pending_target.remove(target);
        }
        if let Some(other) = &state.other_leg_uuid {
            self.by_other_leg.remove(other);
        }
        Some(state)
    }

    /// Delegates to [`LogStream::stats()`].
    pub fn stats(&self) -> &ParseStats {
        self.inner.stats()
    }

    /// Delegates to [`LogStream::drain_unclassified()`].
    pub fn drain_unclassified(&mut self) -> Vec<UnclassifiedLine> {
        self.inner.drain_unclassified()
    }

    fn apply_index_changes(&mut self, uuid: &str, changes: &IndexedFieldChanges) {
        if let Some((old, new)) = &changes.channel_name {
            if let Some(old_name) = old {
                if let Some(set) = self.by_channel_name.get_mut(old_name) {
                    set.remove(uuid);
                    if set.is_empty() {
                        self.by_channel_name.remove(old_name);
                    }
                }
            }
            if let Some(new_name) = new {
                self.by_channel_name
                    .entry(new_name.clone())
                    .or_default()
                    .insert(uuid.to_string());
            }
        }
        if let Some((old, new)) = &changes.pending_bridge_target {
            if let Some(old_target) = old {
                self.by_pending_target.remove(old_target);
            }
            if let Some(new_target) = new {
                self.by_pending_target
                    .insert(new_target.clone(), uuid.to_string());
            }
        }
        if let Some((old, new)) = &changes.other_leg_uuid {
            match new {
                Some(new_leg) => self.index_other_leg(uuid, old.clone(), new_leg),
                None => {
                    if let Some(old_leg) = old {
                        self.by_other_leg.remove(old_leg);
                    }
                }
            }
        }
    }

    /// Record `uuid`'s `other_leg_uuid` transition in `by_other_leg`,
    /// removing the superseded key so a stale entry cannot mislink a later
    /// `New Channel` back-link. Every write to the index goes through here.
    fn index_other_leg(&mut self, uuid: &str, old_leg: Option<String>, new_leg: &str) {
        if let Some(old) = old_leg {
            if old != new_leg {
                self.by_other_leg.remove(&old);
            }
        }
        self.by_other_leg
            .insert(new_leg.to_string(), uuid.to_string());
    }

    /// Cross-session leg linking. Called after `update_from_entry` so per-session
    /// state (bridge target, channel name) is already populated.
    fn link_legs(&mut self, uuid: &str, entry: &LogEntry) {
        // 1. "Originate Resulted in Success ... Peer UUID: BLEG" — authoritative
        if entry.message.contains("Originate Resulted in Success") {
            let a_uuid = uuid.to_string();
            if let Some(peer_uuid) = parse_originate_success(&entry.message) {
                let a_old_pending = self
                    .sessions
                    .get(&a_uuid)
                    .and_then(|s| s.pending_bridge_target.clone());

                let mut a_old_leg = None;
                if let Some(a_state) = self.sessions.get_mut(&a_uuid) {
                    a_old_leg = a_state.other_leg_uuid.replace(peer_uuid.clone());
                    a_state.pending_bridge_target = None;
                }
                self.index_other_leg(&a_uuid, a_old_leg, &peer_uuid);
                if let Some(old_target) = a_old_pending {
                    self.by_pending_target.remove(&old_target);
                }

                let b_state = self.sessions.entry(peer_uuid.clone()).or_default();
                let b_old_leg = b_state.other_leg_uuid.replace(a_uuid.clone());
                self.index_other_leg(&peer_uuid, b_old_leg, &a_uuid);
            } else if let Some(chan) = parse_originate_channel(&entry.message) {
                // Fallback for FS builds without `Peer UUID:` suffix (e.g. 1.10.5-dev):
                // link via unique non-terminated b-leg session whose channel_name
                // matches. Candidates in terminal states are stragglers; if zero or
                // multiple live candidates remain, skip (correctness over coverage).
                let candidates: Vec<String> = self
                    .by_channel_name
                    .get(chan)
                    .map(|set| {
                        set.iter()
                            .filter(|u| *u != &a_uuid)
                            .filter(|u| {
                                self.sessions
                                    .get(*u)
                                    .map(|s| !is_terminal_channel_state(s.channel_state.as_deref()))
                                    .unwrap_or(false)
                            })
                            .cloned()
                            .collect()
                    })
                    .unwrap_or_default();

                if candidates.len() == 1 {
                    let b_uuid = candidates.into_iter().next().unwrap();
                    let a_old_pending = self
                        .sessions
                        .get(&a_uuid)
                        .and_then(|s| s.pending_bridge_target.clone());

                    let mut a_old_leg = None;
                    if let Some(a_state) = self.sessions.get_mut(&a_uuid) {
                        a_old_leg = a_state.other_leg_uuid.replace(b_uuid.clone());
                        a_state.pending_bridge_target = None;
                    }
                    let mut b_old_leg = None;
                    if let Some(b_state) = self.sessions.get_mut(&b_uuid) {
                        b_old_leg = b_state.other_leg_uuid.replace(a_uuid.clone());
                    }

                    self.index_other_leg(&a_uuid, a_old_leg, &b_uuid);
                    self.index_other_leg(&b_uuid, b_old_leg, &a_uuid);
                    if let Some(old_target) = a_old_pending {
                        self.by_pending_target.remove(&old_target);
                    }
                }
            }
            return;
        }

        // 2. New Channel on this UUID — check if any other session has a pending bridge
        //    with origination_uuid matching this UUID, or target matching this channel name.
        if let MessageKind::ChannelLifecycle { detail } = &entry.message_kind {
            if let Some(channel_name) = parse_new_channel(detail) {
                let b_uuid = uuid.to_string();

                // O(1) index lookups instead of full scan
                let a_uuid_found = self
                    .by_other_leg
                    .get(&b_uuid)
                    .cloned()
                    .or_else(|| self.by_pending_target.get(&channel_name).cloned())
                    .filter(|a| a != &b_uuid);

                if let Some(a_uuid) = a_uuid_found {
                    let a_old_pending = self
                        .sessions
                        .get(&a_uuid)
                        .and_then(|s| s.pending_bridge_target.clone());

                    let mut a_old_leg = None;
                    if let Some(a_state) = self.sessions.get_mut(&a_uuid) {
                        a_old_leg = a_state.other_leg_uuid.replace(b_uuid.clone());
                        a_state.pending_bridge_target = None;
                    }
                    let mut b_old_leg = None;
                    if let Some(b_state) = self.sessions.get_mut(&b_uuid) {
                        b_old_leg = b_state.other_leg_uuid.replace(a_uuid.clone());
                    }

                    self.index_other_leg(&a_uuid, a_old_leg, &b_uuid);
                    self.index_other_leg(&b_uuid, b_old_leg, &a_uuid);
                    if let Some(old_target) = a_old_pending {
                        self.by_pending_target.remove(&old_target);
                    }
                }
            }
        }
    }
}

impl<I: Iterator<Item = String>> Iterator for SessionTracker<I> {
    type Item = EnrichedEntry;

    fn next(&mut self) -> Option<EnrichedEntry> {
        let entry = self.inner.next()?;

        if entry.uuid.is_empty() {
            return Some(EnrichedEntry {
                entry,
                session: None,
            });
        }

        let uuid = entry.uuid.clone();
        let state = self.sessions.entry(uuid.clone()).or_default();

        // Snapshot indexed fields before the pre-hook and diff after the
        // post-hook so hook-set fields maintain the cross-session indexes
        // exactly like built-in extraction.
        let old_channel_name = state.channel_name.clone();
        let old_pending_bridge_target = state.pending_bridge_target.clone();
        let old_other_leg_uuid = state.other_leg_uuid.clone();

        if let Some(hook) = &self.pre_hook {
            hook(&entry, state);
        }

        state.update_from_entry(&entry);

        self.link_legs(&uuid, &entry);

        if let Some(hook) = &self.post_hook {
            let state = self.sessions.get_mut(&uuid).unwrap();
            hook(&entry, state);
        }

        let changes = IndexedFieldChanges::diff(
            old_channel_name,
            old_pending_bridge_target,
            old_other_leg_uuid,
            self.sessions.get(&uuid).unwrap(),
        );
        self.apply_index_changes(&uuid, &changes);

        let snapshot = self.sessions.get(&uuid).unwrap().snapshot();

        Some(EnrichedEntry {
            entry,
            session: Some(snapshot),
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    const UUID1: &str = "a1b2c3d4-e5f6-7890-abcd-ef1234567890";
    const UUID2: &str = "b2c3d4e5-f6a7-8901-bcde-f12345678901";
    const UUID3: &str = "c3d4e5f6-a7b8-9012-cdef-234567890123";
    const TS1: &str = "2025-01-15 10:30:45.123456";
    const TS2: &str = "2025-01-15 10:30:46.234567";

    fn full_line(uuid: &str, ts: &str, msg: &str) -> String {
        format!("{uuid} {ts} 95.97% [DEBUG] sofia.c:100 {msg}")
    }

    fn collect_enriched(lines: Vec<String>) -> Vec<EnrichedEntry> {
        let stream = LogStream::new(lines.into_iter());
        SessionTracker::new(stream).collect()
    }

    #[test]
    fn system_line_no_session() {
        let lines = vec![format!(
            "{TS1} 95.97% [INFO] mod_event_socket.c:1772 Event Socket command"
        )];
        let entries = collect_enriched(lines);
        assert_eq!(entries.len(), 1);
        assert!(entries[0].session.is_none());
    }

    #[test]
    fn dialplan_context_propagation() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Channel-Name: [sofia/internal/+15550001234@192.0.2.1]"),
            format!("{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 answer"),
            format!("{UUID1} Dialplan: sofia/internal/+15550001234@192.0.2.1 parsing [public->global] continue=true"),
            full_line(UUID1, TS2, "Some later event"),
        ];
        let entries = collect_enriched(lines);
        let last = entries.last().unwrap();
        let session = last.session.as_ref().unwrap();
        assert_eq!(session.dialplan_context.as_deref(), Some("public"));
        assert_eq!(session.dialplan_from.as_deref(), Some("public"));
        assert_eq!(session.dialplan_to.as_deref(), Some("global"));
    }

    #[test]
    fn processing_line_extracts_context() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "Processing 5551234567->5559876543 in context public",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(session.dialplan_context.as_deref(), Some("public"));
        assert_eq!(session.dialplan_from.as_deref(), Some("5551234567"));
        assert_eq!(session.dialplan_to.as_deref(), Some("5559876543"));
    }

    #[test]
    fn initial_context_preserved_across_transfers() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "Processing 5551234567->5559876543 in context public",
            ),
            full_line(
                UUID1,
                TS2,
                "Processing 5551234567->start_recording in context recordings",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let entries: Vec<_> = tracker.by_ref().collect();

        let first = entries[0].session.as_ref().unwrap();
        assert_eq!(
            first.initial_context.as_deref(),
            Some("public"),
            "initial_context set on first Processing line"
        );
        assert_eq!(first.dialplan_context.as_deref(), Some("public"));

        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.initial_context.as_deref(),
            Some("public"),
            "initial_context keeps the first context seen"
        );
        assert_eq!(
            state.dialplan_context.as_deref(),
            Some("recordings"),
            "dialplan_context tracks the current context"
        );
        assert_eq!(state.dialplan_to.as_deref(), Some("start_recording"));
    }

    #[test]
    fn new_channel_sets_channel_name() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "New Channel sofia/internal-v4/sos [a1b2c3d4-e5f6-7890-abcd-ef1234567890]",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.channel_name.as_deref(),
            Some("sofia/internal-v4/sos")
        );
    }

    #[test]
    fn originate_success_links_both_legs() {
        // "Originate Resulted in Success" contains both the A-leg UUID (line prefix)
        // and B-leg UUID (Peer UUID field). Both legs should learn about each other.
        let lines = vec![
            full_line(UUID2, TS1, "New Channel sofia/esinet1-v6-tcp/sip:target.example.com [b2c3d4e5-f6a7-8901-bcde-f12345678901]"),
            full_line(UUID1, TS2, "Originate Resulted in Success: [sofia/esinet1-v6-tcp/sip:target.example.com] Peer UUID: b2c3d4e5-f6a7-8901-bcde-f12345678901"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "A-leg other_leg_uuid set from Originate Resulted in Success"
        );

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "B-leg other_leg_uuid points back to A-leg"
        );
    }

    #[test]
    fn originate_success_channel_fallback_links_legs() {
        // FS 1.10.5-dev and similar omit `Peer UUID:` from "Originate Resulted in Success".
        // The b-leg's New Channel populates channel_name 3.5 s before originate; the
        // fallback path matches by channel name when the Peer UUID is absent.
        let lines = vec![
            full_line(
                UUID2,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [b2c3d4e5-f6a7-8901-bcde-f12345678901]",
            ),
            full_line(
                UUID1,
                TS2,
                "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744]",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "A-leg linked to B-leg via channel-name fallback when Peer UUID absent"
        );

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "B-leg linked back to A-leg"
        );
    }

    #[test]
    fn originate_success_peer_uuid_wins_over_channel_fallback() {
        // When Peer UUID is present, channel-name fallback must not fire — even if
        // another session shares the channel name. Peer UUID is authoritative.
        let lines = vec![
            full_line(
                UUID2,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [b2c3d4e5-f6a7-8901-bcde-f12345678901]",
            ),
            full_line(
                UUID3,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [c3d4e5f6-a7b8-9012-cdef-234567890123]",
            ),
            full_line(
                UUID1,
                TS2,
                "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744] Peer UUID: b2c3d4e5-f6a7-8901-bcde-f12345678901",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "Peer UUID wins over channel-name match"
        );

        let decoy = tracker.sessions().get(UUID3).unwrap();
        assert_eq!(
            decoy.other_leg_uuid, None,
            "Decoy session sharing channel name is not touched"
        );
    }

    #[test]
    fn originate_success_channel_fallback_skips_when_ambiguous() {
        // Two b-leg candidates share the same channel name. The fallback must not
        // guess — correctness over coverage.
        let lines = vec![
            full_line(
                UUID2,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [b2c3d4e5-f6a7-8901-bcde-f12345678901]",
            ),
            full_line(
                UUID3,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [c3d4e5f6-a7b8-9012-cdef-234567890123]",
            ),
            full_line(
                UUID1,
                TS2,
                "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744]",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid, None,
            "Ambiguous channel name yields no link"
        );
        assert_eq!(tracker.sessions().get(UUID2).unwrap().other_leg_uuid, None);
        assert_eq!(tracker.sessions().get(UUID3).unwrap().other_leg_uuid, None);
    }

    #[test]
    fn originate_success_channel_fallback_skips_terminated_candidates() {
        // Two b-leg sessions share the same channel_name, but one is in
        // CS_DESTROY (stale prior call on the same registered phone). The
        // liveness filter must drop the terminated candidate so the live one
        // becomes the unambiguous match.
        let lines = vec![
            full_line(
                UUID2,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [b2c3d4e5-f6a7-8901-bcde-f12345678901]",
            ),
            full_line(
                UUID2,
                TS1,
                "(sofia/internal/6244@192.0.2.72:50744) State Change CS_EXECUTE -> CS_DESTROY",
            ),
            full_line(
                UUID3,
                TS1,
                "New Channel sofia/internal/6244@192.0.2.72:50744 [c3d4e5f6-a7b8-9012-cdef-234567890123]",
            ),
            full_line(
                UUID1,
                TS2,
                "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744]",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID3),
            "Live b-leg wins over CS_DESTROY straggler"
        );

        let live_b = tracker.sessions().get(UUID3).unwrap();
        assert_eq!(
            live_b.other_leg_uuid.as_deref(),
            Some(UUID1),
            "Live b-leg points back to a-leg"
        );

        let stale_b = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            stale_b.other_leg_uuid, None,
            "Terminated b-leg is not touched"
        );
    }

    #[test]
    fn originate_success_channel_fallback_skips_when_no_match() {
        // a-leg fires Originate with a bracketed channel name no session has.
        // Must not panic, must not create a spurious link.
        let lines = vec![full_line(
            UUID1,
            TS2,
            "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744]",
        )];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(a_leg.other_leg_uuid, None);
        assert_eq!(a_leg.pending_bridge_target, None);
    }

    #[test]
    fn bridge_origination_uuid_links_a_leg_immediately() {
        // bridge([origination_uuid=BLEG_UUID,...]) guarantees B-leg UUID from execute args alone.
        // A-leg knows B-leg immediately, B-leg learns A-leg when New Channel appears.
        let lines = vec![
            full_line(UUID1, TS1, "EXECUTE [depth=0] sofia/internal-v6/1232@[2001:db8::10] bridge([origination_uuid=b2c3d4e5-f6a7-8901-bcde-f12345678901,leg_timeout=2]sofia/esinet1-v6-tcp/sip:target.example.com)"),
            full_line(UUID2, TS1, "New Channel sofia/esinet1-v6-tcp/sip:target.example.com [b2c3d4e5-f6a7-8901-bcde-f12345678901]"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "A-leg knows B-leg UUID from origination_uuid in bridge args"
        );

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "B-leg knows A-leg once New Channel correlates"
        );
    }

    #[test]
    fn bridge_target_matches_new_channel() {
        // bridge() without origination_uuid — B-leg UUID is auto-generated by FS.
        // Match via bridge target channel matching next New Channel with same target.
        let lines = vec![
            full_line(UUID1, TS1, "EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 bridge(sofia/gateway/carrier/+15559876543)"),
            full_line(UUID1, TS1, "Parsing session specific variables"),
            full_line(UUID2, TS1, "New Channel sofia/gateway/carrier/+15559876543 [b2c3d4e5-f6a7-8901-bcde-f12345678901]"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "A-leg linked to B-leg via bridge target matching New Channel"
        );

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "B-leg linked back to A-leg"
        );
    }

    #[test]
    fn originate_success_corrects_wrong_target_match() {
        // Bridge target matching guessed UUID2 as B-leg, but originate success reveals
        // the actual B-leg is UUID3. The authoritative success message must override.
        let lines = vec![
            full_line(UUID1, TS1, "EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 bridge(sofia/gateway/carrier/+15559876543)"),
            full_line(UUID2, TS1, "New Channel sofia/gateway/carrier/+15559876543 [b2c3d4e5-f6a7-8901-bcde-f12345678901]"),
            full_line(UUID1, TS2, "Originate Resulted in Success: [sofia/gateway/carrier/+15559876543] Peer UUID: c3d4e5f6-a7b8-9012-cdef-234567890123"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID3),
            "Originate success overrides earlier target-match guess"
        );

        let real_b_leg = tracker.sessions().get(UUID3).unwrap();
        assert_eq!(
            real_b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "Real B-leg points back to A-leg"
        );
    }

    #[test]
    fn channel_data_other_leg_uuid() {
        // Other-Leg-Unique-ID in CHANNEL_DATA (post-bridge info dump) sets other_leg_uuid
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Other-Leg-Unique-ID: [{UUID2}]"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.other_leg_uuid.as_deref(),
            Some(UUID2),
            "other_leg_uuid set from Other-Leg-Unique-ID CHANNEL_DATA field"
        );
    }

    #[test]
    fn relink_removes_stale_by_other_leg_entry() {
        // B first points at C (Other-Leg-Unique-ID), then an authoritative
        // Peer UUID relinks B to A. The superseded C-keyed by_other_leg entry
        // must be removed — otherwise a later New Channel on C back-links to
        // B and clobbers the authoritative A<->B pair.
        let lines = vec![
            full_line(UUID2, TS1, "CHANNEL_DATA:"),
            format!("{UUID2} Other-Leg-Unique-ID: [{UUID3}]"),
            full_line(
                UUID1,
                TS2,
                &format!(
                    "Originate Resulted in Success: [sofia/internal/6244@192.0.2.72:50744] Peer UUID: {UUID2}"
                ),
            ),
            full_line(
                UUID3,
                TS2,
                &format!("New Channel sofia/external/dest@192.0.2.9 [{UUID3}]"),
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(a_leg.other_leg_uuid.as_deref(), Some(UUID2));

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "authoritative Peer UUID link must survive the unrelated New Channel"
        );

        let c_leg = tracker.sessions().get(UUID3).unwrap();
        assert_eq!(
            c_leg.other_leg_uuid, None,
            "New Channel on C must not back-link via the superseded index entry"
        );
    }

    #[test]
    fn channel_data_populates_session() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Channel-Name: [sofia/internal/+15550001234@192.0.2.1]"),
            format!("{UUID1} Channel-State: [CS_EXECUTE]"),
            "variable_sip_call_id: [test123@192.0.2.1]".to_string(),
            "variable_direction: [inbound]".to_string(),
        ];
        let entries = collect_enriched(lines);
        assert_eq!(entries.len(), 1);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.channel_name.as_deref(),
            Some("sofia/internal/+15550001234@192.0.2.1")
        );
        assert_eq!(session.channel_state.as_deref(), Some("CS_EXECUTE"));
    }

    #[test]
    fn variables_learned_from_channel_data() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            "variable_sip_call_id: [test123@192.0.2.1]".to_string(),
            "variable_direction: [inbound]".to_string(),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();
        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.variables.get("sip_call_id").map(|s| s.as_str()),
            Some("test123@192.0.2.1")
        );
        assert_eq!(
            state.variables.get("direction").map(|s| s.as_str()),
            Some("inbound")
        );
    }

    #[test]
    fn multi_line_variable_survives_attached_rescan() {
        // The block carries the reassembled multi-line value; re-scanning the
        // raw attached opening fragment must not clobber it back to "v=0".
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Channel-Name: [sofia/internal/+15550001234@192.0.2.1]"),
            format!("{UUID1} variable_switch_r_sdp: [v=0"),
            "o=FreeSWITCH 1737000000 1737000001 IN IP4 192.0.2.10".to_string(),
            "s=FreeSWITCH".to_string(),
            "c=IN IP4 192.0.2.10".to_string(),
            "m=audio 30000 RTP/AVP 0 101".to_string(),
            "]".to_string(),
            format!("{UUID1} variable_direction: [inbound]"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let state = tracker.sessions().get(UUID1).unwrap();
        let sdp = state
            .variables
            .get("switch_r_sdp")
            .expect("switch_r_sdp variable present");
        assert!(
            sdp.contains('\n'),
            "expected full reassembled value, got fragment: {sdp:?}"
        );
        assert!(sdp.starts_with("v=0\n"));
        assert!(sdp.contains("m=audio 30000 RTP/AVP 0 101"));
        assert_eq!(
            state.variables.get("direction").map(|s| s.as_str()),
            Some("inbound")
        );
        assert_eq!(
            state.channel_name.as_deref(),
            Some("sofia/internal/+15550001234@192.0.2.1")
        );
    }

    #[test]
    fn attached_processing_line_updates_context() {
        // Format C continuation: a `Processing ...` line attached under a
        // primary entry must update dialplan context like the primary path.
        let lines = vec![
            full_line(UUID1, TS1, "Ring-Ready sofia/internal-v4/sos!"),
            format!(
                "{UUID1} Processing Extension 1263 <1263>->start_recording in context recordings"
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(state.dialplan_context.as_deref(), Some("recordings"));
        assert_eq!(
            state.dialplan_from.as_deref(),
            Some("Extension 1263 <1263>")
        );
        assert_eq!(state.dialplan_to.as_deref(), Some("start_recording"));
        assert_eq!(
            state.initial_destination.as_deref(),
            Some("start_recording")
        );
    }

    #[test]
    fn variables_learned_from_set_execute() {
        let lines = vec![
            full_line(UUID1, TS1, "First"),
            format!("{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 set(call_direction=inbound)"),
            full_line(UUID1, TS2, "After set"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let entries: Vec<_> = tracker.by_ref().collect();
        assert_eq!(entries.len(), 3);
        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.variables.get("call_direction").map(|s| s.as_str()),
            Some("inbound")
        );
    }

    #[test]
    fn variables_learned_from_export_execute() {
        let lines = vec![
            full_line(UUID1, TS1, "First"),
            format!("{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 export(originate_timeout=3600)"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();
        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.variables.get("originate_timeout").map(|s| s.as_str()),
            Some("3600")
        );
    }

    #[test]
    fn session_isolation_between_uuids() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "Processing 5551111111->5552222222 in context public",
            ),
            full_line(
                UUID2,
                TS2,
                "Processing 5553333333->5554444444 in context private",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();
        let s1 = tracker.sessions().get(UUID1).unwrap();
        let s2 = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(s1.dialplan_context.as_deref(), Some("public"));
        assert_eq!(s2.dialplan_context.as_deref(), Some("private"));
        assert_eq!(s1.dialplan_from.as_deref(), Some("5551111111"));
        assert_eq!(s2.dialplan_from.as_deref(), Some("5553333333"));
    }

    #[test]
    fn processing_line_with_regex_type_and_angle_bracket_caller() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "Processing Emergency S R <5550001234>->start_recording in context recordings",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(session.initial_context.as_deref(), Some("recordings"));
        assert_eq!(session.dialplan_context.as_deref(), Some("recordings"));
        assert_eq!(
            session.dialplan_from.as_deref(),
            Some("Emergency S R <5550001234>")
        );
        assert_eq!(session.dialplan_to.as_deref(), Some("start_recording"));
    }

    #[test]
    fn processing_line_extension_format() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "Processing Extension 1263 <1263>->start_recording in context recordings",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(session.initial_context.as_deref(), Some("recordings"));
        assert_eq!(
            session.dialplan_from.as_deref(),
            Some("Extension 1263 <1263>")
        );
        assert_eq!(session.dialplan_to.as_deref(), Some("start_recording"));
    }

    #[test]
    fn parse_processing_line_anchors_on_last_arrow() {
        let dest = |msg: &str| parse_processing_line(msg).map(|dp| dp.to);
        assert_eq!(
            dest("Processing Anonymous <anonymous>->5550001234 in context public").as_deref(),
            Some("5550001234"),
        );
        assert_eq!(
            dest("Processing 5550009999 <5550009999>->5550001234 in context public").as_deref(),
            Some("5550001234"),
        );
        assert_eq!(
            dest("Processing Jane Doe <5550009999>->5550001234 in context internal").as_deref(),
            Some("5550001234"),
        );
        // Hostile caller_id_name containing `->` must not be mistaken for the boundary.
        assert_eq!(
            dest("Processing Weird -> Name <5550009999>->5550001234 in context internal")
                .as_deref(),
            Some("5550001234"),
        );
        // Feature-context destination is non-numeric but still parsed.
        assert_eq!(
            dest("Processing Jane Doe <5550009999>->start_recording in context features")
                .as_deref(),
            Some("start_recording"),
        );
    }

    #[test]
    fn initial_destination_first_wins() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "Processing Jane Doe <5550009999>->5550001234 in context public",
            ),
            full_line(
                UUID1,
                TS2,
                "Processing Jane Doe <5550009999>->5550001234 in context transit",
            ),
            full_line(
                UUID1,
                TS2,
                "Processing Jane Doe <5550009999>->start_recording in context features",
            ),
            full_line(
                UUID1,
                TS2,
                "Processing Jane Doe <5550009999>->check_end_call in context features",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();

        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.initial_destination.as_deref(),
            Some("5550001234"),
            "initial_destination keeps the dialed number from the first Processing line"
        );
        assert_eq!(
            state.dialplan_to.as_deref(),
            Some("check_end_call"),
            "dialplan_to is last-wins and gets clobbered by feature-context routing"
        );
    }

    #[test]
    fn state_change_updates_channel_state() {
        let lines = vec![full_line(UUID1, TS1, "State Change CS_INIT -> CS_ROUTING")];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(session.channel_state.as_deref(), Some("CS_ROUTING"));
    }

    #[test]
    fn callstate_change_updates_channel_state() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "(sofia/internal-v4/sos) Callstate Change DOWN -> RINGING",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(session.channel_state.as_deref(), Some("RINGING"));
    }

    #[test]
    fn state_change_overrides_callstate() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "(sofia/internal-v4/sos) Callstate Change DOWN -> RINGING",
            ),
            full_line(
                UUID1,
                TS2,
                "(sofia/internal-v4/sos) State Change CS_CONSUME_MEDIA -> CS_EXCHANGE_MEDIA",
            ),
        ];
        let entries = collect_enriched(lines);
        assert_eq!(
            entries[0]
                .session
                .as_ref()
                .unwrap()
                .channel_state
                .as_deref(),
            Some("RINGING")
        );
        assert_eq!(
            entries[1]
                .session
                .as_ref()
                .unwrap()
                .channel_state
                .as_deref(),
            Some("CS_EXCHANGE_MEDIA")
        );
    }

    #[test]
    fn bleg_lifecycle_extracts_data_from_processing() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "New Channel sofia/internal-v4/sos [a1b2c3d4-e5f6-7890-abcd-ef1234567890]",
            ),
            full_line(
                UUID1,
                TS1,
                "(sofia/internal-v4/sos) State Change CS_NEW -> CS_INIT",
            ),
            full_line(
                UUID1,
                TS1,
                "(sofia/internal-v4/sos) State Change CS_INIT -> CS_ROUTING",
            ),
            full_line(
                UUID1,
                TS1,
                "(sofia/internal-v4/sos) State Change CS_ROUTING -> CS_CONSUME_MEDIA",
            ),
            full_line(
                UUID1,
                TS1,
                "(sofia/internal-v4/sos) Callstate Change DOWN -> RINGING",
            ),
            full_line(
                UUID1,
                TS2,
                "(sofia/internal-v4/sos) State Change CS_CONSUME_MEDIA -> CS_EXCHANGE_MEDIA",
            ),
            full_line(
                UUID1,
                TS2,
                "Processing Emergency S R <5550001234>->start_recording in context recordings",
            ),
            full_line(
                UUID1,
                TS2,
                "(sofia/internal-v4/sos) State Change CS_EXCHANGE_MEDIA -> CS_HANGUP",
            ),
        ];
        let entries = collect_enriched(lines);

        let after_ringing = entries[4].session.as_ref().unwrap();
        assert_eq!(after_ringing.channel_state.as_deref(), Some("RINGING"));
        assert!(after_ringing.initial_context.is_none());

        let after_processing = entries[6].session.as_ref().unwrap();
        assert_eq!(
            after_processing.channel_state.as_deref(),
            Some("CS_EXCHANGE_MEDIA")
        );
        assert_eq!(
            after_processing.initial_context.as_deref(),
            Some("recordings")
        );
        assert_eq!(
            after_processing.dialplan_from.as_deref(),
            Some("Emergency S R <5550001234>")
        );
        assert_eq!(
            after_processing.dialplan_to.as_deref(),
            Some("start_recording")
        );

        let after_hangup = entries[7].session.as_ref().unwrap();
        assert_eq!(after_hangup.channel_state.as_deref(), Some("CS_HANGUP"));
        assert_eq!(after_hangup.initial_context.as_deref(), Some("recordings"));
    }

    #[test]
    fn channel_name_from_new_channel() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "New Channel sofia/internal-v4/sos [a1b2c3d4-e5f6-7890-abcd-ef1234567890]",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.channel_name.as_deref(),
            Some("sofia/internal-v4/sos")
        );
    }

    #[test]
    fn remove_session() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "Processing 5551111111->5552222222 in context public",
        )];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();
        assert!(tracker.sessions().contains_key(UUID1));
        let removed = tracker.remove_session(UUID1).unwrap();
        assert_eq!(removed.dialplan_context.as_deref(), Some("public"));
        assert!(!tracker.sessions().contains_key(UUID1));
    }

    #[test]
    fn stats_delegation() {
        let lines = vec![
            full_line(UUID1, TS1, "First"),
            full_line(UUID1, TS2, "Second"),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream);
        let _: Vec<_> = tracker.by_ref().collect();
        assert_eq!(tracker.stats().lines_processed, 2);
    }

    #[test]
    fn snapshot_reflects_cumulative_state() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Channel-Name: [sofia/internal/+15550001234@192.0.2.1]"),
            format!("{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 set(foo=bar)"),
            full_line(
                UUID1,
                TS2,
                "Processing 5551111111->5552222222 in context public",
            ),
        ];
        let entries = collect_enriched(lines);
        assert_eq!(entries.len(), 3);
        let first = entries[0].session.as_ref().unwrap();
        assert_eq!(
            first.channel_name.as_deref(),
            Some("sofia/internal/+15550001234@192.0.2.1"),
        );
        assert!(first.dialplan_context.is_none());

        let last = entries[2].session.as_ref().unwrap();
        assert_eq!(
            last.channel_name.as_deref(),
            Some("sofia/internal/+15550001234@192.0.2.1"),
        );
        assert_eq!(last.dialplan_context.as_deref(), Some("public"));
    }

    #[test]
    fn post_hook_sets_other_leg_uuid() {
        let lines = vec![
            full_line(UUID1, TS1, "First entry"),
            format!(
                "{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 set(api_result=+OK {UUID2} Job-UUID: ...)"
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_post_hook(|entry, state| {
            if let MessageKind::Execute {
                application,
                arguments,
                ..
            } = &entry.message_kind
            {
                if application == "set" {
                    if let Some(value) = arguments.strip_prefix("api_result=+OK ") {
                        let uuid = value.split_whitespace().next().unwrap_or("");
                        if uuid.len() == 36 && state.other_leg_uuid.is_none() {
                            state.other_leg_uuid = Some(uuid.to_string());
                        }
                    }
                }
            }
        });

        let entries: Vec<_> = tracker.by_ref().collect();
        assert_eq!(entries.len(), 2);

        let session = entries[1].session.as_ref().unwrap();
        assert_eq!(
            session.other_leg_uuid.as_deref(),
            Some(UUID2),
            "post_hook should detect uuid_bridge API result"
        );
    }

    #[test]
    fn post_hook_does_not_override_builtin() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Other-Leg-Unique-ID: [{UUID2}]"),
            format!(
                "{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 set(api_result=+OK {UUID3} Job-UUID: ...)"
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_post_hook(|entry, state| {
            if let MessageKind::Execute {
                application,
                arguments,
                ..
            } = &entry.message_kind
            {
                if application == "set" {
                    if let Some(value) = arguments.strip_prefix("api_result=+OK ") {
                        let uuid = value.split_whitespace().next().unwrap_or("");
                        if uuid.len() == 36 && state.other_leg_uuid.is_none() {
                            state.other_leg_uuid = Some(uuid.to_string());
                        }
                    }
                }
            }
        });

        let entries: Vec<_> = tracker.by_ref().collect();
        assert_eq!(entries.len(), 2);

        let session = entries[1].session.as_ref().unwrap();
        assert_eq!(
            session.other_leg_uuid.as_deref(),
            Some(UUID2),
            "built-in Other-Leg-Unique-ID takes precedence over hook"
        );
    }

    #[test]
    fn pre_hook_runs_before_builtin() {
        let lines = vec![full_line(UUID1, TS1, "State Change CS_INIT -> CS_ROUTING")];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_pre_hook(|_entry, state| {
            state.channel_state = Some("PRE_SET".to_string());
        });
        let entries: Vec<_> = tracker.by_ref().collect();
        assert_eq!(
            entries[0]
                .session
                .as_ref()
                .unwrap()
                .channel_state
                .as_deref(),
            Some("CS_ROUTING"),
            "built-in overwrites pre_hook value when no guard"
        );
    }

    #[test]
    fn post_hook_runs_after_builtin() {
        let lines = vec![full_line(UUID1, TS1, "State Change CS_INIT -> CS_ROUTING")];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_post_hook(|_entry, state| {
            if state.channel_state.as_deref() == Some("CS_ROUTING") {
                state
                    .variables
                    .insert("routing_seen".to_string(), "true".to_string());
            }
        });
        let _: Vec<_> = tracker.by_ref().collect();
        let state = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            state.variables.get("routing_seen").map(|s| s.as_str()),
            Some("true"),
            "post_hook can read fields set by built-in"
        );
    }

    #[test]
    fn post_hook_other_leg_uuid_maintains_index_for_backlink() {
        // A hook-set other_leg_uuid must reach by_other_leg so the B-leg's
        // later New Channel back-links to the A-leg like built-in sources do.
        let lines = vec![
            full_line(UUID1, TS1, "First entry"),
            format!(
                "{UUID1} EXECUTE [depth=0] sofia/internal/+15550001234@192.0.2.1 set(api_result=+OK {UUID2})"
            ),
            full_line(
                UUID2,
                TS2,
                "New Channel sofia/internal/target@192.0.2.9 [b2c3d4e5-f6a7-8901-bcde-f12345678901]",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_post_hook(|entry, state| {
            if let MessageKind::Execute {
                application,
                arguments,
                ..
            } = &entry.message_kind
            {
                if application == "set" {
                    if let Some(value) = arguments.strip_prefix("api_result=+OK ") {
                        let uuid = value.split_whitespace().next().unwrap_or("");
                        if uuid.len() == 36 && state.other_leg_uuid.is_none() {
                            state.other_leg_uuid = Some(uuid.to_string());
                        }
                    }
                }
            }
        });
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(a_leg.other_leg_uuid.as_deref(), Some(UUID2));

        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(
            b_leg.other_leg_uuid.as_deref(),
            Some(UUID1),
            "B-leg back-links via by_other_leg index populated by the hook"
        );
    }

    #[test]
    fn pre_hook_channel_name_maintains_index_for_originate_fallback() {
        // A hook-set channel_name must reach by_channel_name so the
        // originate-success channel-name fallback can find the B-leg.
        let lines = vec![
            full_line(UUID2, TS1, "custom-channel-announce sofia/custom/6244"),
            full_line(
                UUID1,
                TS2,
                "Originate Resulted in Success: [sofia/custom/6244]",
            ),
        ];
        let stream = LogStream::new(lines.into_iter());
        let mut tracker = SessionTracker::new(stream).with_pre_hook(|entry, state| {
            if let Some(chan) = entry.message.strip_prefix("custom-channel-announce ") {
                state.channel_name = Some(chan.to_string());
            }
        });
        let _: Vec<_> = tracker.by_ref().collect();

        let a_leg = tracker.sessions().get(UUID1).unwrap();
        assert_eq!(
            a_leg.other_leg_uuid.as_deref(),
            Some(UUID2),
            "fallback finds hook-named B-leg via by_channel_name index"
        );
        let b_leg = tracker.sessions().get(UUID2).unwrap();
        assert_eq!(b_leg.other_leg_uuid.as_deref(), Some(UUID1));
    }

    #[test]
    fn parse_hangup_extracts_cause() {
        assert_eq!(
            parse_hangup("Hangup sofia/internal/1234 [NORMAL_CLEARING]"),
            Some("NORMAL_CLEARING".to_string())
        );
        assert_eq!(
            parse_hangup("Hangup sofia/internal/1234 [USER_BUSY]"),
            Some("USER_BUSY".to_string())
        );
        assert_eq!(parse_hangup("Some other message"), None);
        assert_eq!(parse_hangup("New Channel sofia/internal/1234 [uuid]"), None);
    }

    #[test]
    fn is_answered_detects_answer_event() {
        assert!(is_answered("sofia/internal/1234 has been answered"));
        assert!(!is_answered("sofia/internal/1234 is ringing"));
        assert!(!is_answered("New Channel sofia/internal/1234"));
    }

    #[test]
    fn hangup_cause_from_lifecycle() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "Hangup sofia/internal/+15550001234@192.0.2.1 [NORMAL_CLEARING]",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.hangup_cause.as_deref(),
            Some("NORMAL_CLEARING"),
            "hangup_cause extracted from ChannelLifecycle Hangup"
        );
    }

    #[test]
    fn answered_at_from_lifecycle() {
        let lines = vec![full_line(
            UUID1,
            TS1,
            "sofia/internal/+15550001234@192.0.2.1 has been answered",
        )];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.answered_at.as_deref(),
            Some(TS1),
            "answered_at captures timestamp when 'has been answered' seen"
        );
    }

    #[test]
    fn answered_at_not_overwritten() {
        let lines = vec![
            full_line(
                UUID1,
                TS1,
                "sofia/internal/+15550001234@192.0.2.1 has been answered",
            ),
            full_line(
                UUID1,
                TS2,
                "sofia/internal/+15550001234@192.0.2.1 has been answered",
            ),
        ];
        let entries = collect_enriched(lines);
        let session = entries[1].session.as_ref().unwrap();
        assert_eq!(
            session.answered_at.as_deref(),
            Some(TS1),
            "answered_at preserves first answer timestamp"
        );
    }

    #[test]
    fn caller_id_name_from_channel_data() {
        let lines = vec![
            full_line(UUID1, TS1, "CHANNEL_DATA:"),
            format!("{UUID1} Caller-Caller-ID-Name: [Test Caller Name]"),
        ];
        let entries = collect_enriched(lines);
        let session = entries[0].session.as_ref().unwrap();
        assert_eq!(
            session.caller_id_name.as_deref(),
            Some("Test Caller Name"),
            "caller_id_name extracted from CHANNEL_DATA"
        );
    }
}