//! `operator_bridge` — POI surfacing + operator command authentication.
//!
//! Real implementation in this batch:
//! - **AZ-678** `internal::auth::HmacOperatorValidator` — HMAC-SHA256
//!   over `(session_token, sequence_number, payload)`; per-session
//!   replay tracker; session registry with TTL; rejection-reason
//!   counters; sliding-window red-health gate.
//! - **AZ-679** `internal::poi_surface::PoiSurfaceMapper` — wire-format
//!   POI events + `PoiDequeued` events pushed through `TelemetrySink`.
//!
//! Real implementation lands in:
//! - AZ-680 `operator_bridge_command_dispatch`
//! - AZ-681 `operator_bridge_safety_and_bit_ack`

pub mod internal;

use std::sync::Arc;

use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use tokio::sync::mpsc;

use shared::contracts::{OperatorCommandSink, TelemetrySink};
use shared::error::{AutopilotError, Result};
use shared::health::{ComponentHealth, HealthLevel};
use shared::models::mission::Coordinate;
use shared::models::operator::OperatorCommand;
use shared::models::operator_event::{DequeueReason, PhotoMetadata};
use shared::models::poi::Poi;

pub use crate::internal::auth::{
    AuthCounters, HmacOperatorValidator, HmacValidatorConfig, REJECTION_REASONS,
};
pub use crate::internal::poi_surface::{PoiSurfaceMapper, PoiSurfaceMetrics};

const NAME: &str = "operator_bridge";

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum OperatorDecision {
    Confirmed,
    Declined,
    TimedOut,
    StartTargetFollow,
    ReleaseTargetFollow,
}

#[derive(Debug, Clone)]
pub struct MiddleWaypointHint {
    pub mission_id: String,
    pub at: Coordinate,
}

#[derive(Debug, Clone)]
pub enum TargetFollowEvent {
    Start { target_id: String },
    Release,
}

pub struct OperatorBridge {
    middle_waypoint_tx: mpsc::Sender<MiddleWaypointHint>,
    target_follow_tx: mpsc::Sender<TargetFollowEvent>,
    middle_waypoint_rx: Option<mpsc::Receiver<MiddleWaypointHint>>,
    target_follow_rx: Option<mpsc::Receiver<TargetFollowEvent>>,
    /// AZ-679 — POI surface mapper. Optional so existing single-arg
    /// constructors (used by tests + early scaffolding) keep working;
    /// composition root wires the real `TelemetrySink` via
    /// `with_telemetry_sink`.
    poi_mapper: Option<Arc<PoiSurfaceMapper>>,
    /// AZ-678 — operator command validator. Same optional-pattern as
    /// `poi_mapper` so legacy callers continue to compile until the
    /// composition root wires it in.
    validator: Option<Arc<HmacOperatorValidator>>,
}

impl OperatorBridge {
    pub fn new(channel_capacity: usize) -> Self {
        let (mw_tx, mw_rx) = mpsc::channel(channel_capacity);
        let (tf_tx, tf_rx) = mpsc::channel(channel_capacity);
        Self {
            middle_waypoint_tx: mw_tx,
            target_follow_tx: tf_tx,
            middle_waypoint_rx: Some(mw_rx),
            target_follow_rx: Some(tf_rx),
            poi_mapper: None,
            validator: None,
        }
    }

    pub fn with_telemetry_sink(mut self, sink: Arc<dyn TelemetrySink>) -> Self {
        self.poi_mapper = Some(Arc::new(PoiSurfaceMapper::new(sink)));
        self
    }

    pub fn with_validator(mut self, validator: Arc<HmacOperatorValidator>) -> Self {
        self.validator = Some(validator);
        self
    }

    pub fn handle(&self) -> OperatorBridgeHandle {
        OperatorBridgeHandle {
            middle_waypoint_tx: self.middle_waypoint_tx.clone(),
            target_follow_tx: self.target_follow_tx.clone(),
            poi_mapper: self.poi_mapper.clone(),
            validator: self.validator.clone(),
        }
    }

    pub fn take_middle_waypoint_receiver(&mut self) -> Option<mpsc::Receiver<MiddleWaypointHint>> {
        self.middle_waypoint_rx.take()
    }

    pub fn take_target_follow_receiver(&mut self) -> Option<mpsc::Receiver<TargetFollowEvent>> {
        self.target_follow_rx.take()
    }
}

#[derive(Clone)]
pub struct OperatorBridgeHandle {
    #[allow(dead_code)]
    middle_waypoint_tx: mpsc::Sender<MiddleWaypointHint>,
    #[allow(dead_code)]
    target_follow_tx: mpsc::Sender<TargetFollowEvent>,
    poi_mapper: Option<Arc<PoiSurfaceMapper>>,
    validator: Option<Arc<HmacOperatorValidator>>,
}

impl OperatorBridgeHandle {
    /// AZ-679 — surface a POI to the operator and await the decision.
    /// Today returns `NotImplemented` (the decision loop is AZ-680);
    /// the surface event itself IS pushed (via the configured
    /// `TelemetrySink`), so the operator UI receives it.
    pub async fn surface_poi(&self, poi: Poi) -> Result<OperatorDecision> {
        match &self.poi_mapper {
            Some(mapper) => {
                mapper.surface(&poi, None).await?;
                Err(AutopilotError::NotImplemented(
                    "operator_bridge::surface_poi → decision loop (AZ-680)",
                ))
            }
            None => Err(AutopilotError::NotImplemented(
                "operator_bridge::surface_poi (no telemetry sink wired)",
            )),
        }
    }

    /// AZ-679 — surface a POI together with photo metadata (preferred
    /// path when the source detection carries an ROI snapshot).
    pub async fn surface_poi_with_photo(
        &self,
        poi: &Poi,
        photo_metadata: PhotoMetadata,
    ) -> Result<()> {
        let mapper = self.poi_mapper.as_ref().ok_or_else(|| {
            AutopilotError::Internal("surface_poi_with_photo: telemetry sink not wired".into())
        })?;
        mapper.surface(poi, Some(photo_metadata)).await.map(|_| ())
    }

    /// AZ-679 — emit a `PoiDequeued` event (rotation / age-out /
    /// completion). Called by `scan_controller` through the bridge.
    pub async fn emit_poi_dequeued(&self, poi_id: uuid::Uuid, reason: DequeueReason) -> Result<()> {
        let mapper = self.poi_mapper.as_ref().ok_or_else(|| {
            AutopilotError::Internal("emit_poi_dequeued: telemetry sink not wired".into())
        })?;
        mapper.emit_dequeued(poi_id, reason).await
    }

    pub fn poi_metrics(&self) -> Option<PoiSurfaceMetrics> {
        self.poi_mapper.as_ref().map(|m| m.metrics())
    }

    pub fn health(&self) -> ComponentHealth {
        let mut h = ComponentHealth::disabled(NAME);
        if self.poi_mapper.is_none() && self.validator.is_none() {
            return h;
        }
        // Once any sub-component is wired we surface green by default,
        // upgrade to red if the validator's signature-failure window
        // crosses the threshold (AC-5).
        h.level = HealthLevel::Green;
        if let Some(v) = &self.validator {
            if v.health_is_red() {
                h.level = HealthLevel::Red;
            }
            let c = v.counters();
            h.detail = Some(format!(
                "validated_total={} sig_invalid={} replay={} session_unknown={} session_expired={}",
                c.validated_total(),
                c.reason(shared::contracts::operator_auth::AuthError::SignatureInvalid),
                c.reason(shared::contracts::operator_auth::AuthError::ReplayDetected),
                c.reason(shared::contracts::operator_auth::AuthError::SessionUnknown),
                c.reason(shared::contracts::operator_auth::AuthError::SessionExpired),
            ));
        }
        h
    }
}

#[async_trait]
impl OperatorCommandSink for OperatorBridgeHandle {
    async fn dispatch(&self, _command: OperatorCommand) -> Result<()> {
        Err(AutopilotError::NotImplemented(
            "operator_bridge::dispatch (AZ-680)",
        ))
    }
}

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

    #[test]
    fn it_compiles_without_wiring() {
        let h = OperatorBridge::new(8).handle();
        assert_eq!(h.health().level, shared::health::HealthLevel::Disabled);
    }

    #[test]
    fn health_green_once_validator_wired() {
        // Arrange
        let validator = Arc::new(HmacOperatorValidator::with_default_config());

        // Act
        let bridge = OperatorBridge::new(8).with_validator(validator);
        let h = bridge.handle().health();

        // Assert
        assert_eq!(h.level, shared::health::HealthLevel::Green);
        assert!(h.detail.unwrap().contains("validated_total=0"));
    }
}