//! RPC handlers for the FIPS mesh transport subsystem.
//!
//! Surface is deliberately thin: a read-only `fips.status`, a user-gated
//! `fips.check-update`, a stubbed `fips.apply-update`, and a
//! `fips.install` that (re-)materialises the daemon config + key and
//! activates the service. All writes go through `sudo` helpers in
//! `crate::fips`.

use super::RpcHandler;
use crate::fips;
use anyhow::Result;

impl RpcHandler {
    pub(super) async fn handle_fips_status(&self) -> Result<serde_json::Value> {
        let status = fips::FipsStatus::query(&self.config.data_dir).await;
        Ok(serde_json::to_value(status)?)
    }

    pub(super) async fn handle_fips_check_update(&self) -> Result<serde_json::Value> {
        let check = fips::update::check().await?;
        Ok(serde_json::to_value(check)?)
    }

    pub(super) async fn handle_fips_apply_update(&self) -> Result<serde_json::Value> {
        fips::update::apply().await?;
        Ok(serde_json::json!({ "applied": true }))
    }

    /// Install config + key into /etc/fips and activate the service.
    /// Intended to be called:
    ///   - once by the seed-onboarding flow, right after the FIPS key
    ///     is written to /data/identity/fips_key, and
    ///   - on user demand from the dashboard if something drifted.
    pub(super) async fn handle_fips_install(&self) -> Result<serde_json::Value> {
        let identity_dir = fips::identity_dir_from(&self.config.data_dir);
        fips::config::install(&identity_dir).await?;
        fips::service::activate(fips::SERVICE_UNIT).await?;
        let status = fips::FipsStatus::query(&self.config.data_dir).await;
        Ok(serde_json::to_value(status)?)
    }

    /// Restart whichever fips unit is supervising the daemon on this host.
    /// Nodes installed from the archipelago ISO use `archipelago-fips.service`;
    /// nodes that had the upstream debian package set up first may only have
    /// `fips.service`. We resolve the active one via `service::active_unit()`
    /// so the UI button is never a no-op.
    pub(super) async fn handle_fips_restart(&self) -> Result<serde_json::Value> {
        let unit = fips::service::active_unit().await;
        fips::service::restart(unit).await?;
        Ok(serde_json::json!({ "restarted": true, "unit": unit }))
    }

    /// Full reconnect: stop the daemon, bring it back, wait for the DHT
    /// bootstrap window, poll the identity-cache + peer list, and
    /// classify what recovered (or didn't) so the UI can explain it to
    /// the user instead of showing a generic failure.
    ///
    /// Runtime: ~20s. Needs an RPC timeout ≥ 45s on the client.
    pub(super) async fn handle_fips_reconnect(&self) -> Result<serde_json::Value> {
        let identity_dir = fips::identity_dir_from(&self.config.data_dir);
        let before = fips::FipsStatus::query(&self.config.data_dir).await;

        // Heal the pre-fix bech32-text fips_key.pub → 32-raw-bytes
        // mismatch. The daemon silently authenticates with a garbage
        // pubkey when the .pub file is 63-char text, which looks like
        // "anchor unreachable" to the user even though the real fault
        // was an identity malformed on the node itself. Re-install the
        // config + keys so /etc/fips gets the healed .pub.
        let key_src = identity_dir.join("fips_key");
        let pub_src = identity_dir.join("fips_key.pub");
        if key_src.exists() {
            let _ = fips::config::normalize_pub_file(&key_src, &pub_src).await;
            // Re-install refreshes /etc/fips/fips.pub from the healed
            // source. No-op if nothing changed.
            let _ = fips::config::install(&identity_dir).await;
        }

        // Operate on whichever fips unit is actually up — nodes that
        // have the upstream `fips.service` rather than the
        // archipelago-managed `archipelago-fips.service` used to see
        // Reconnect silently fail because we stopped a unit that
        // didn't exist. Clean stop+start rather than `restart` so a
        // daemon that fails to come back up surfaces as
        // service_active=false instead of quietly sticking with the
        // old process.
        let unit = fips::service::active_unit().await;
        let _ = fips::service::stop(unit).await;
        tokio::time::sleep(std::time::Duration::from_millis(800)).await;
        fips::service::activate(unit).await?;

        // Re-push seed anchors after restart so freshly-bound daemons
        // don't have to wait 5 min for the periodic apply loop.
        if let Ok(list) = fips::anchors::load(&self.config.data_dir).await {
            if !list.is_empty() {
                let _ = fips::anchors::apply(&list).await;
            }
        }

        // Anchor bootstrap window: poll the status every ~3s for up to
        // 20s. Bail as soon as the anchor is connected.
        let mut last_status: Option<fips::FipsStatus> = None;
        let deadline = std::time::Instant::now() + std::time::Duration::from_secs(20);
        loop {
            tokio::time::sleep(std::time::Duration::from_secs(3)).await;
            let s = fips::FipsStatus::query(&self.config.data_dir).await;
            if s.anchor_connected {
                last_status = Some(s);
                break;
            }
            last_status = Some(s);
            if std::time::Instant::now() >= deadline {
                break;
            }
        }
        let after = last_status.unwrap_or_else(|| before.clone());

        let recovered = after.anchor_connected && !before.anchor_connected;
        let likely_cause = if after.anchor_connected {
            "connected"
        } else if !after.service_active {
            "daemon_down"
        } else if !after.key_present {
            "no_seed_key"
        } else if after.authenticated_peer_count == 0 {
            // Daemon is up with a key but hasn't authenticated any
            // peers — almost always outbound UDP/8668 dropped by the
            // local firewall/router, or the anchor itself being down.
            "no_outbound_udp_or_anchor_down"
        } else {
            "peers_but_no_anchor"
        };
        let hint = match likely_cause {
            "connected" => "An anchor is reachable.",
            "daemon_down" => "The FIPS daemon didn't come back up — check the FIPS service on this host.",
            "no_seed_key" => "No seed-derived FIPS key on disk. Re-run the onboarding unlock step.",
            "no_outbound_udp_or_anchor_down" =>
                "Daemon is running but no peers handshook. Your router / ISP might be blocking outbound UDP 8668, or every configured anchor could be down. Add a reachable peer in Seed Anchors.",
            "peers_but_no_anchor" =>
                "Mesh has peers but none of them are anchors we recognise. Add your cluster's anchor in Seed Anchors.",
            _ => "",
        };

        Ok(serde_json::json!({
            "recovered": recovered,
            "likely_cause": likely_cause,
            "hint": hint,
            "before": before,
            "after": after,
        }))
    }

    /// List the seed-anchor entries configured on this node.
    pub(super) async fn handle_fips_list_seed_anchors(&self) -> Result<serde_json::Value> {
        let list = fips::anchors::load(&self.config.data_dir).await?;
        Ok(serde_json::json!({ "seed_anchors": list }))
    }

    /// Add (or update) a seed anchor and immediately push it into the
    /// running daemon. Params: `{ npub, address, transport?, label? }`.
    pub(super) async fn handle_fips_add_seed_anchor(
        &self,
        params: &serde_json::Value,
    ) -> Result<serde_json::Value> {
        let anchor: fips::anchors::SeedAnchor = serde_json::from_value(params.clone())
            .map_err(|e| anyhow::anyhow!("bad seed anchor payload: {}", e))?;
        if !anchor.npub.starts_with("npub1") {
            anyhow::bail!("npub must be bech32 (npub1...)");
        }
        if !anchor.address.contains(':') {
            anyhow::bail!("address must be host:port (e.g. 192.168.1.116:8668)");
        }
        let list =
            fips::anchors::add(&self.config.data_dir, anchor.clone()).await?;
        // Push just the newly-added anchor into the running daemon so
        // the user sees effect without waiting for the periodic apply.
        let results = fips::anchors::apply(&[anchor]).await;
        Ok(serde_json::json!({
            "seed_anchors": list,
            "apply": results.iter().map(|r| {
                serde_json::json!({ "npub": r.npub, "ok": r.ok, "message": r.message })
            }).collect::<Vec<_>>(),
        }))
    }

    /// Remove a seed anchor by npub. Params: `{ npub }`. Does NOT tear
    /// down an already-authenticated peer connection — it only stops
    /// us from re-dialing the anchor on the next apply cycle.
    pub(super) async fn handle_fips_remove_seed_anchor(
        &self,
        params: &serde_json::Value,
    ) -> Result<serde_json::Value> {
        let npub = params
            .get("npub")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("missing npub"))?;
        let list = fips::anchors::remove(&self.config.data_dir, npub).await?;
        Ok(serde_json::json!({ "seed_anchors": list }))
    }

    /// Re-apply all seed anchors to the running daemon. Useful after a
    /// FIPS restart or when the user wants to force a reconnection
    /// attempt without waiting for the periodic apply loop.
    pub(super) async fn handle_fips_apply_seed_anchors(&self) -> Result<serde_json::Value> {
        let list = fips::anchors::load(&self.config.data_dir).await?;
        let results = fips::anchors::apply(&list).await;
        Ok(serde_json::json!({
            "applied": results.len(),
            "results": results.iter().map(|r| {
                serde_json::json!({ "npub": r.npub, "ok": r.ok, "message": r.message })
            }).collect::<Vec<_>>(),
        }))
    }
}