//! Embedded MCP server. Claude Code (running inside the agent container)
//! launches this as a stdio child via `--mcp-config`; tool calls land here
//! and are translated to `AgentRequest::*` / `ManagerRequest::*` against
//! hyperhive's own per-container unix socket at `/run/hive/mcp.sock`.
//!
//! Two protocols, two surfaces:
//! - **hyperhive socket** at `/run/hive/mcp.sock` — JSON-line, our
//!   broker-routed protocol. Unaffected by this module.
//! - **MCP stdio** owned by this module — what claude actually speaks.
//!
//! Two server flavors:
//! - `AgentServer` — sub-agent tools (`send`, `recv`).
//! - `ManagerServer` — agent tools + lifecycle (`request_spawn`, `kill`,
//!   `request_apply_commit`).
//!
//! Both go through the same `run_tool_envelope` helper so logging + status
//! line stay uniform.

use std::future::Future;
use std::path::PathBuf;

use anyhow::Result;
use rmcp::{
    ServerHandler, ServiceExt, handler::server::wrapper::Parameters, schemars, tool, tool_handler,
    tool_router, transport::stdio,
};

use crate::client;

/// Wire-protocol-agnostic view of a hyperhive socket response. Both
/// `AgentResponse` and `ManagerResponse` convert into this so the tool
/// formatters can be shared between `AgentServer` and `ManagerServer`.
#[derive(Debug)]
pub enum SocketReply {
    Ok,
    Err(String),
    /// `id` is the broker's row id — not surfaced to claude but
    /// useful for harness-side bookkeeping (not used in this module
    /// today; the bin loops drive ack via `AckTurn` instead of
    /// per-id). `redelivered` triggers the "may already be handled"
    /// hint in `format_recv` so claude sees it when draining the
    /// inbox in-turn.
    Message {
        from: String,
        body: String,
        id: i64,
        redelivered: bool,
    },
    Empty,
    Status(u64),
    QuestionQueued(i64),
    Recent(Vec<hive_sh4re::InboxRow>),
    Logs(String),
    LooseEnds(Vec<hive_sh4re::LooseEnd>),
    PendingRemindersCount(u64),
    Whoami {
        name: String,
        role: String,
        hyperhive_rev: Option<String>,
    },
}

impl From<hive_sh4re::AgentResponse> for SocketReply {
    fn from(r: hive_sh4re::AgentResponse) -> Self {
        match r {
            hive_sh4re::AgentResponse::Ok => Self::Ok,
            hive_sh4re::AgentResponse::Err { message } => Self::Err(message),
            hive_sh4re::AgentResponse::Message {
                from,
                body,
                id,
                redelivered,
            } => Self::Message {
                from,
                body,
                id,
                redelivered,
            },
            hive_sh4re::AgentResponse::Empty => Self::Empty,
            hive_sh4re::AgentResponse::Status { unread } => Self::Status(unread),
            hive_sh4re::AgentResponse::Recent { rows } => Self::Recent(rows),
            hive_sh4re::AgentResponse::QuestionQueued { id } => Self::QuestionQueued(id),
            hive_sh4re::AgentResponse::LooseEnds { loose_ends } => Self::LooseEnds(loose_ends),
            hive_sh4re::AgentResponse::PendingRemindersCount { count } => {
                Self::PendingRemindersCount(count)
            }
            hive_sh4re::AgentResponse::Whoami {
                name,
                role,
                hyperhive_rev,
            } => Self::Whoami {
                name,
                role,
                hyperhive_rev,
            },
        }
    }
}

impl From<hive_sh4re::ManagerResponse> for SocketReply {
    fn from(r: hive_sh4re::ManagerResponse) -> Self {
        match r {
            hive_sh4re::ManagerResponse::Ok => Self::Ok,
            hive_sh4re::ManagerResponse::Err { message } => Self::Err(message),
            hive_sh4re::ManagerResponse::Message {
                from,
                body,
                id,
                redelivered,
            } => Self::Message {
                from,
                body,
                id,
                redelivered,
            },
            hive_sh4re::ManagerResponse::Empty => Self::Empty,
            hive_sh4re::ManagerResponse::Status { unread } => Self::Status(unread),
            hive_sh4re::ManagerResponse::QuestionQueued { id } => Self::QuestionQueued(id),
            hive_sh4re::ManagerResponse::Recent { rows } => Self::Recent(rows),
            hive_sh4re::ManagerResponse::Logs { content } => Self::Logs(content),
            hive_sh4re::ManagerResponse::LooseEnds { loose_ends } => Self::LooseEnds(loose_ends),
            hive_sh4re::ManagerResponse::PendingRemindersCount { count } => {
                Self::PendingRemindersCount(count)
            }
            hive_sh4re::ManagerResponse::Whoami {
                name,
                role,
                hyperhive_rev,
            } => Self::Whoami {
                name,
                role,
                hyperhive_rev,
            },
        }
    }
}

/// Format helper for "send-like" tools (anything that expects an `Ok`).
/// `tool` and `ok_msg` only appear in the result string; they don't change
/// behavior.
pub fn format_ack(resp: Result<SocketReply, anyhow::Error>, tool: &str, ok_msg: String) -> String {
    match resp {
        Ok(SocketReply::Ok) => ok_msg,
        Ok(SocketReply::Err(m)) => format!("{tool} failed: {m}"),
        Ok(other) => format!("{tool} unexpected response: {other:?}"),
        Err(e) => format!("{tool} transport error: {e:#}"),
    }
}

/// Format helper for `recv` tools: `Message` → from + body block;
/// `Empty` → marker; anything else surfaces as an error. When the
/// broker tags the row as `redelivered` (popped before, never acked,
/// resurfaced after a harness restart) a short banner is prepended
/// so claude knows the side-effects of any previous handling may
/// already have happened.
pub fn format_recv(resp: Result<SocketReply, anyhow::Error>) -> String {
    match resp {
        Ok(SocketReply::Message {
            from,
            body,
            redelivered,
            ..
        }) => {
            let banner = if redelivered { REDELIVERY_HINT } else { "" };
            format!("{banner}from: {from}\n\n{body}")
        }
        Ok(SocketReply::Empty) => "(empty)".into(),
        Ok(SocketReply::Err(m)) => format!("recv failed: {m}"),
        Ok(other) => format!("recv unexpected response: {other:?}"),
        Err(e) => format!("recv transport error: {e:#}"),
    }
}

/// Header prepended to message bodies that were popped by a prior
/// harness session, never acked (turn crash / OOM / restart), and
/// resurfaced by `RequeueInflight` on this session's boot. Same
/// string surfaces in the wake prompt (see the bin loops) and the
/// in-turn `recv` tool result so claude sees the warning either way.
pub const REDELIVERY_HINT: &str =
    "[redelivered after harness restart — may already be handled]\n";

/// Format helper for `get_loose_ends`: renders a short bulleted list
/// of pending approvals + questions + reminders. Empty list collapses
/// to a clear marker so claude doesn't go hunting for a payload that
/// isn't there.
pub fn format_loose_ends(resp: Result<SocketReply, anyhow::Error>) -> String {
    use std::fmt::Write as _;
    let loose_ends = match resp {
        Ok(SocketReply::LooseEnds(t)) => t,
        Ok(SocketReply::Err(m)) => return format!("get_loose_ends failed: {m}"),
        Ok(other) => return format!("get_loose_ends unexpected response: {other:?}"),
        Err(e) => return format!("get_loose_ends transport error: {e:#}"),
    };
    if loose_ends.is_empty() {
        return "(no loose ends)".to_owned();
    }
    let mut out = format!("{} loose end(s):\n", loose_ends.len());
    for t in &loose_ends {
        match t {
            hive_sh4re::LooseEnd::Approval {
                id,
                agent,
                commit_ref,
                description,
                age_seconds,
            } => {
                let desc = description
                    .as_deref()
                    .map(|d| format!(" — {d}"))
                    .unwrap_or_default();
                let _ = writeln!(
                    out,
                    "- approval #{id} ({agent} @ {commit_ref}, {age_seconds}s old){desc}"
                );
            }
            hive_sh4re::LooseEnd::Question {
                id,
                asker,
                target,
                question,
                age_seconds,
            } => {
                let to = target.as_deref().unwrap_or("operator");
                let _ = writeln!(
                    out,
                    "- question #{id} ({asker} → {to}, {age_seconds}s old): {question}"
                );
            }
            hive_sh4re::LooseEnd::Reminder {
                id,
                owner,
                message,
                due_at,
                age_seconds,
            } => {
                let _ = writeln!(
                    out,
                    "- reminder #{id} ({owner}, scheduled {age_seconds}s ago, due_at={due_at}): {message}"
                );
            }
        }
    }
    out
}

/// Parse the user-facing `kind` string for `cancel_loose_end` into the
/// wire enum. Accepts a small alias set so claude doesn't have to
/// remember the exact spelling (`"q"` / `"r"` shorthand falls out
/// for free).
fn parse_loose_end_kind(raw: &str) -> Result<hive_sh4re::CancelLooseEndKind, String> {
    match raw.trim().to_ascii_lowercase().as_str() {
        "question" | "q" => Ok(hive_sh4re::CancelLooseEndKind::Question),
        "reminder" | "r" => Ok(hive_sh4re::CancelLooseEndKind::Reminder),
        other => Err(format!(
            "cancel_loose_end: unknown kind '{other}' (expected \"question\" or \"reminder\")"
        )),
    }
}

/// Canonical user-facing label for a `CancelLooseEndKind` — used in
/// the success ack so the caller always sees `"question"` /
/// `"reminder"` instead of whatever alias they passed in (`"q"` /
/// `"r"`).
fn loose_end_kind_label(kind: hive_sh4re::CancelLooseEndKind) -> &'static str {
    match kind {
        hive_sh4re::CancelLooseEndKind::Question => "question",
        hive_sh4re::CancelLooseEndKind::Reminder => "reminder",
    }
}

/// Format helper for `whoami`: renders the identity block as a short
/// human-readable string. Skips fields that are `None` so the output
/// doesn't carry dead placeholders.
pub fn format_whoami(resp: Result<SocketReply, anyhow::Error>) -> String {
    match resp {
        Ok(SocketReply::Whoami {
            name,
            role,
            hyperhive_rev,
        }) => {
            let rev = hyperhive_rev.as_deref().unwrap_or("<unknown>");
            format!("name: {name}\nrole: {role}\nhyperhive_rev: {rev}")
        }
        Ok(SocketReply::Err(m)) => format!("whoami failed: {m}"),
        Ok(other) => format!("whoami unexpected response: {other:?}"),
        Err(e) => format!("whoami transport error: {e:#}"),
    }
}

/// Common envelope around every MCP tool handler: pre-log → run →
/// post-log. The inbox-status hint used to be appended to every tool
/// result; that lives in the wake prompt + UI header now, so tool
/// results stay clean.
pub async fn run_tool_envelope<F>(tool: &'static str, args: String, body: F) -> String
where
    F: Future<Output = String>,
{
    tracing::info!(tool, %args, "tool: request");
    let result = body.await;
    tracing::info!(tool, result = %result, "tool: result");
    result
}

/// Append a short note to a tool result when the underlying socket call
/// took retries to land. Lets claude distinguish "my request was wrong"
/// from "c0re flickered and the harness rode it out" — without the
/// hint, a tool result that took 30s to come back looks identical to a
/// content failure and the model would burn a turn retrying it.
pub fn annotate_retries(mut s: String, retries: u32) -> String {
    if retries > 0 {
        use std::fmt::Write as _;
        let suffix = if retries == 1 { "retry" } else { "retries" };
        let _ = write!(
            s,
            "\n\n(note: hive socket connect needed {retries} {suffix} — c0re likely \
             restarted. Your request did succeed on the final attempt; no action needed.)"
        );
    }
    s
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct SendArgs {
    /// Logical agent name to deliver the message to (e.g. `"manager"`,
    /// `"alice"`, or the literal `"operator"` for the dashboard's T4LK box).
    pub to: String,
    /// Message body. Plain text; the broker doesn't parse it.
    pub body: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct RecvArgs {
    /// How long to long-poll for a new message before returning the
    /// empty marker. Capped at 60s server-side. Default (None) is
    /// 30s. Useful when an agent wants to throttle wakes without
    /// actually napping — pick a longer wait to coalesce bursts.
    #[serde(default)]
    pub wait_seconds: Option<u64>,
}

/// MCP tool args for `remind`. Exactly one of `delay_seconds` or
/// `at_unix_timestamp` must be set; both / neither is a tool-side error.
/// Hides the tagged `ReminderTiming` enum behind a flatter schema so the
/// model picks one field instead of building `{"timing_type": "in_seconds",
/// "seconds": 60}` shaped objects.
#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct RemindArgs {
    /// Body that lands in your inbox when the reminder fires (sender
    /// will appear as `reminder`). Soft cap at 4 KiB inline — anything
    /// larger gets auto-persisted to a file under
    /// `/agents/<you>/state/reminders/auto-<ts>.md` and the inbox
    /// message becomes a short pointer. Pass `file_path` if you want
    /// to control the destination yourself.
    pub message: String,
    /// Fire `delay_seconds` from now (relative). Set this OR
    /// `at_unix_timestamp`, not both.
    #[serde(default)]
    pub delay_seconds: Option<u64>,
    /// Fire at this absolute unix timestamp (seconds since epoch). Set
    /// this OR `delay_seconds`, not both.
    #[serde(default)]
    pub at_unix_timestamp: Option<i64>,
    /// Optional path to a file the scheduler should reference instead of
    /// inlining a long `message`. Use this for large payloads (research
    /// notes, file lists, intermediate state). Path must be reachable from
    /// the agent's container — typically under `/agents/<you>/state/`.
    #[serde(default)]
    pub file_path: Option<String>,
}

/// Per-agent tool surface. Holds the socket path so each tool call doesn't
/// re-derive it; the socket itself is the per-container `/run/hive/mcp.sock`.
#[derive(Debug, Clone)]
pub struct AgentServer {
    socket: PathBuf,
}

impl AgentServer {
    #[must_use]
    pub fn new(socket: PathBuf) -> Self {
        Self { socket }
    }

    /// Issue any `AgentRequest` through the retry-aware client and pull
    /// the reply through `SocketReply`. Returns the retry count so tool
    /// handlers can annotate their result (see `annotate_retries`).
    async fn dispatch(
        &self,
        req: hive_sh4re::AgentRequest,
    ) -> (Result<SocketReply, anyhow::Error>, u32) {
        match client::request_retried::<_, hive_sh4re::AgentResponse>(&self.socket, &req).await {
            Ok((r, n)) => (Ok(SocketReply::from(r)), n),
            Err(e) => (Err(e), 0),
        }
    }
}

#[tool_router]
impl AgentServer {
    #[tool(
        description = "Send a message to another hyperhive agent (or to the operator). \
            Use this to talk to peers or to surface output for the human at the dashboard."
    )]
    async fn send(&self, Parameters(args): Parameters<SendArgs>) -> String {
        let log = format!("{args:?}");
        let to = args.to.clone();
        if let Err(refusal) = check_send_allowed(&to) {
            return run_tool_envelope("send", log, async move { refusal }).await;
        }
        run_tool_envelope("send", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::Send {
                    to: args.to,
                    body: args.body,
                })
                .await;
            annotate_retries(format_ack(resp, "send", format!("sent to {to}")), retries)
        })
        .await
    }

    #[tool(
        description = "Surface a structured question to either the operator OR a peer agent. \
        Returns immediately with a question id — do NOT wait inline. When the recipient \
        answers, a system message with event `question_answered { id, question, answer, \
        answerer }` lands in your inbox; handle it on a future turn. \n\n\
        Recipient: omit `to` (or set `to: \"operator\"`) for the human operator on the \
        dashboard. Set `to: \"<agent-name>\"` to ask a peer agent — they receive a \
        `question_asked { id, asker, question, options, multi }` event in their inbox \
        and answer via `mcp__hyperhive__answer`. \n\n\
        `options` is advisory: pass a short fixed-choice list when applicable, otherwise \
        leave empty for free text. Set `multi: true` to let the answerer pick multiple \
        options (checkboxes on the dashboard, hint to the agent otherwise) — answer comes \
        back as a comma-separated string. Set `ttl_seconds` to auto-cancel a \
        no-longer-relevant question — on expiry the answer is `[expired]` (with \
        `answerer: \"ttl-watchdog\"`) and the same `question_answered` event fires."
    )]
    async fn ask(&self, Parameters(args): Parameters<AskArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("ask", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::Ask {
                    question: args.question,
                    options: args.options,
                    multi: args.multi,
                    ttl_seconds: args.ttl_seconds,
                    to: args.to,
                })
                .await;
            let s = match resp {
                Ok(SocketReply::QuestionQueued(id)) => format!(
                    "question queued (id={id}); answer will arrive as a system \
                     `question_answered` event in your inbox"
                ),
                Ok(SocketReply::Err(m)) => format!("ask failed: {m}"),
                Ok(other) => format!("ask unexpected response: {other:?}"),
                Err(e) => format!("ask transport error: {e:#}"),
            };
            annotate_retries(s, retries)
        })
        .await
    }

    #[tool(
        description = "Answer a question that was routed to YOU via a `question_asked` system \
        event in your inbox. Pass the `id` from that event and your `answer` string. The \
        answer will surface in the asker's inbox as a `question_answered { id, question, \
        answer, answerer: <your-name> }` event. \n\n\
        Authorisation is strict — you can only answer questions where you are the declared \
        target (i.e. the asker did `ask(to: \"<your-name>\", ...)`). Trying to answer an \
        operator-targeted question or a question addressed to a different agent will fail."
    )]
    async fn answer(&self, Parameters(args): Parameters<AnswerArgs>) -> String {
        let log = format!("{args:?}");
        let id = args.id;
        run_tool_envelope("answer", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::Answer {
                    id,
                    answer: args.answer,
                })
                .await;
            annotate_retries(
                format_ack(resp, "answer", format!("answered question {id}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Pop one message from this agent's inbox. Returns the sender and body, \
            or an empty marker if nothing is waiting. Without `wait_seconds` (or with 0) the \
            call returns immediately — a cheap 'anything pending?' peek. Pass a positive \
            `wait_seconds` (capped at 180) to park the turn waiting for new work — incoming \
            messages wake you instantly, otherwise the call returns empty at the timeout. \
            That's strictly better than a fixed shell `sleep`. Typical pattern: when you have \
            nothing else useful to do, call `recv(wait_seconds: 180)` to park until \
            something arrives."
    )]
    async fn recv(&self, Parameters(args): Parameters<RecvArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("recv", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::Recv {
                    wait_seconds: args.wait_seconds,
                })
                .await;
            annotate_retries(format_recv(resp), retries)
        })
        .await
    }

    #[tool(
        description = "List loose ends pending against this agent: unanswered questions \
        where you are the asker (waiting on someone) or the target (someone's waiting on \
        you), pending reminders you scheduled, plus — for the manager only — pending \
        approvals you submitted that the operator hasn't acted on yet. Cheap server-side \
        sweep, no args. Useful at turn start to remember what you owe / what's owed to \
        you without scrolling inbox history. Output is a short bulleted list with ids, \
        ages in seconds, and the relevant context. Each `question` or `reminder` row \
        can be cancelled by passing its id + kind to `cancel_loose_end`. Empty result \
        is reported clearly."
    )]
    async fn get_loose_ends(&self) -> String {
        run_tool_envelope("get_loose_ends", String::new(), async move {
            let (resp, retries) = self.dispatch(hive_sh4re::AgentRequest::GetLooseEnds).await;
            annotate_retries(format_loose_ends(resp), retries)
        })
        .await
    }

    #[tool(
        description = "Self-introspection: returns your own canonical agent name (the \
        socket-identity name, NOT the prompt-substituted label), role (`agent`), and \
        the current hyperhive rev hive-c0re is running against. No args. Useful when \
        you want a trustworthy identity stamp for state files / commit messages / \
        cross-agent attribution that won't drift across renames or session-continue \
        boundaries where the system-prompt label could be stale."
    )]
    async fn whoami(&self) -> String {
        run_tool_envelope("whoami", String::new(), async move {
            let (resp, retries) = self.dispatch(hive_sh4re::AgentRequest::Whoami).await;
            annotate_retries(format_whoami(resp), retries)
        })
        .await
    }

    #[tool(
        description = "Cancel an open thread you own — a `question` you asked (the \
        asker gets `[cancelled by <you>]` as the answer and unblocks) or a `reminder` \
        you scheduled (hard-deleted before it fires). `kind` is `\"question\"` or \
        `\"reminder\"`; `id` is the row id from the matching `get_loose_ends` entry \
        or the `question_queued` reply you got when you submitted. Auth: you can only \
        cancel rows where you're the asker / owner. Returns `ok` or an error string."
    )]
    async fn cancel_loose_end(&self, Parameters(args): Parameters<CancelLooseEndArgs>) -> String {
        let log = format!("{args:?}");
        let id = args.id;
        run_tool_envelope("cancel_loose_end", log, async move {
            let kind = match parse_loose_end_kind(&args.kind) {
                Ok(k) => k,
                Err(e) => return e,
            };
            let kind_label = loose_end_kind_label(kind);
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::CancelLooseEnd { kind, id })
                .await;
            annotate_retries(
                format_ack(resp, "cancel_loose_end", format!("cancelled {kind_label} {id}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Schedule a reminder that lands in this agent's own inbox at a future \
        time (sender will appear as `reminder`). Use for self-paced follow-ups: 'check task \
        status in 60s', 'retry failed deploy at 14:00 UTC', 'nudge me when the operator's \
        deploy window opens'. Set EXACTLY ONE of `delay_seconds` (fire N seconds from now) \
        or `at_unix_timestamp` (fire at absolute epoch second). Body soft-caps at 4 KiB \
        inline — anything larger gets auto-persisted to a file under your \
        `/agents/<you>/state/reminders/` dir and the inbox message becomes a short pointer; \
        pass `file_path` if you want to control the destination yourself. Returns \
        immediately — the reminder lives in the broker until due."
    )]
    async fn remind(&self, Parameters(args): Parameters<RemindArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("remind", log, async move {
            let timing = match (args.delay_seconds, args.at_unix_timestamp) {
                (Some(_), Some(_)) => {
                    return "remind failed: pass exactly one of `delay_seconds` or \
                            `at_unix_timestamp`, not both"
                        .to_string();
                }
                (None, None) => {
                    return "remind failed: pass exactly one of `delay_seconds` or \
                            `at_unix_timestamp`"
                        .to_string();
                }
                (Some(s), None) => hive_sh4re::ReminderTiming::InSeconds { seconds: s },
                (None, Some(t)) => hive_sh4re::ReminderTiming::At { unix_timestamp: t },
            };
            let (resp, retries) = self
                .dispatch(hive_sh4re::AgentRequest::Remind {
                    message: args.message,
                    timing,
                    file_path: args.file_path,
                })
                .await;
            annotate_retries(format_ack(resp, "remind", "reminder scheduled".to_string()), retries)
        })
        .await
    }
}

#[tool_handler(
    instructions = "You are a hyperhive agent. Use `send` to talk to peers (by their logical \
        name) or to the operator (recipient `operator`). Use `recv` to drain your inbox one \
        message at a time. Use `remind` to schedule a future wake-up message for yourself."
)]
impl ServerHandler for AgentServer {}

/// Run the agent MCP server over stdio. Returns when the client disconnects.
pub async fn serve_agent_stdio(socket: PathBuf) -> Result<()> {
    let server = AgentServer::new(socket);
    let service = server.serve(stdio()).await?;
    service.waiting().await?;
    Ok(())
}

/// Run the manager MCP server over stdio. Same idea, different tool surface.
pub async fn serve_manager_stdio(socket: PathBuf) -> Result<()> {
    let server = ManagerServer::new(socket);
    let service = server.serve(stdio()).await?;
    service.waiting().await?;
    Ok(())
}

// -----------------------------------------------------------------------------
// Manager tool surface
// -----------------------------------------------------------------------------

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct RequestSpawnArgs {
    /// New sub-agent name (≤9 chars). Queues a Spawn approval; the
    /// operator approves on the dashboard before the container is created.
    pub name: String,
    /// Optional description shown on the dashboard approval card so the
    /// operator knows what the new agent is for without a separate message.
    #[serde(default)]
    pub description: Option<String>,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct KillArgs {
    /// Sub-agent name (without the `h-` container prefix).
    pub name: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct StartArgs {
    /// Sub-agent name (without the `h-` container prefix).
    pub name: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct RestartArgs {
    /// Sub-agent name (without the `h-` container prefix).
    pub name: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct UpdateArgs {
    /// Sub-agent name (without the `h-` container prefix).
    pub name: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct AskArgs {
    /// The question to surface.
    pub question: String,
    /// Optional fixed-choice answers. The dashboard renders these as
    /// chips alongside a free-text fallback ("Other…") so the operator
    /// is never trapped by an incomplete list; peer-agent recipients
    /// see the list in their inbox event and can return any string.
    #[serde(default)]
    pub options: Vec<String>,
    /// When true, options are rendered as checkboxes — the answerer
    /// can pick any subset. The answer comes back as a single string
    /// with selections joined by ", ". Ignored when `options` is empty.
    #[serde(default)]
    pub multi: bool,
    /// Optional auto-cancel after `ttl_seconds` (capped server-side at
    /// 6 hours). On expiry the question resolves with answer
    /// `[expired]` and the asker receives the usual
    /// `question_answered` system event (with `answerer:
    /// "ttl-watchdog"`). `None` (default) = wait indefinitely.
    #[serde(default)]
    pub ttl_seconds: Option<u64>,
    /// Recipient. Omit (or pass `"operator"`) to ask the human
    /// operator via the dashboard. Pass another agent's logical name
    /// to ask that peer — they receive a `question_asked` event in
    /// their inbox and answer via `mcp__hyperhive__answer`.
    #[serde(default)]
    pub to: Option<String>,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct AnswerArgs {
    /// Id of the question being answered — comes from the
    /// `question_asked` event in your inbox.
    pub id: i64,
    /// Free-text answer body. Soft-capped at 4 KiB by the same
    /// `MESSAGE_MAX_BYTES` limit as `send`; keep it short or write the
    /// detail to a file and pass a path.
    pub answer: String,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct CancelLooseEndArgs {
    /// Which kind of thread to cancel — `"question"` for an open
    /// `ask` that's still waiting on an answer, `"reminder"` for a
    /// scheduled `remind` that hasn't fired yet. Use the `kind`
    /// field straight off the `get_loose_ends` row.
    pub kind: String,
    /// Row id from the matching `get_loose_ends` entry (or the
    /// `question_queued` reply when you submitted it).
    pub id: i64,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct RequestApplyCommitArgs {
    /// Agent whose config repo the commit lives in (use `"hm1nd"` for the
    /// manager's own config).
    pub agent: String,
    /// Git sha (full or short) pointing at the proposed `agent.nix`.
    pub commit_ref: String,
    /// Optional description shown on the dashboard approval card so the
    /// operator knows what the change does without opening the diff.
    #[serde(default)]
    pub description: Option<String>,
}

#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
pub struct GetLogsArgs {
    /// Logical name of the sub-agent container to fetch logs for.
    pub agent: String,
    /// How many journal lines to return (default: 50, max: 500).
    #[serde(default)]
    pub lines: Option<u32>,
}

#[derive(Debug, Clone)]
pub struct ManagerServer {
    socket: PathBuf,
}

impl ManagerServer {
    #[must_use]
    pub fn new(socket: PathBuf) -> Self {
        Self { socket }
    }

    /// Helper: issue any `ManagerRequest` through the retry-aware
    /// client, convert the reply through `SocketReply`, and return the
    /// retry count alongside so the tool handler can `annotate_retries`
    /// on the final string.
    async fn dispatch(
        &self,
        req: hive_sh4re::ManagerRequest,
    ) -> (Result<SocketReply, anyhow::Error>, u32) {
        match client::request_retried::<_, hive_sh4re::ManagerResponse>(&self.socket, &req).await {
            Ok((r, n)) => (Ok(SocketReply::from(r)), n),
            Err(e) => (Err(e), 0),
        }
    }
}

#[tool_router]
impl ManagerServer {
    #[tool(
        description = "Send a message to a sub-agent (by logical name), to another agent, \
        or to the operator (recipient `operator`, surfaces in the dashboard)."
    )]
    async fn send(&self, Parameters(args): Parameters<SendArgs>) -> String {
        let log = format!("{args:?}");
        let to = args.to.clone();
        run_tool_envelope("send", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Send {
                    to: args.to,
                    body: args.body,
                })
                .await;
            annotate_retries(format_ack(resp, "send", format!("sent to {to}")), retries)
        })
        .await
    }

    #[tool(
        description = "Pop one message from the manager inbox. Returns sender + body, or \
        empty. Without `wait_seconds` (or 0) returns immediately — a cheap inbox peek. \
        Pass a positive value (capped at 180) to park until either a message arrives \
        or the timeout fires; prefer a long wait (120 or 180) over ending a turn \
        early when you have nothing else to do."
    )]
    async fn recv(&self, Parameters(args): Parameters<RecvArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("recv", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Recv {
                    wait_seconds: args.wait_seconds,
                })
                .await;
            annotate_retries(format_recv(resp), retries)
        })
        .await
    }

    #[tool(
        description = "Queue a Spawn approval for a brand-new sub-agent. The operator \
        approves on the dashboard before the container is actually created."
    )]
    async fn request_spawn(&self, Parameters(args): Parameters<RequestSpawnArgs>) -> String {
        let log = format!("{args:?}");
        let name = args.name.clone();
        run_tool_envelope("request_spawn", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::RequestSpawn {
                    name: args.name,
                    description: args.description,
                })
                .await;
            annotate_retries(
                format_ack(
                    resp,
                    "request_spawn",
                    format!("spawn approval queued for {name}"),
                ),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Stop a sub-agent container (graceful). The state dir is kept; \
        recreating reuses prior config + Claude credentials. No approval required."
    )]
    async fn kill(&self, Parameters(args): Parameters<KillArgs>) -> String {
        let log = format!("{args:?}");
        let name = args.name.clone();
        run_tool_envelope("kill", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Kill { name: args.name })
                .await;
            annotate_retries(format_ack(resp, "kill", format!("killed {name}")), retries)
        })
        .await
    }

    #[tool(
        description = "Start a stopped sub-agent container. No approval required — \
        lifecycle ops on existing containers are at the manager's discretion."
    )]
    async fn start(&self, Parameters(args): Parameters<StartArgs>) -> String {
        let log = format!("{args:?}");
        let name = args.name.clone();
        run_tool_envelope("start", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Start { name: args.name })
                .await;
            annotate_retries(
                format_ack(resp, "start", format!("started {name}")),
                retries,
            )
        })
        .await
    }

    #[tool(description = "Restart a sub-agent container (stop + start). No approval required.")]
    async fn restart(&self, Parameters(args): Parameters<RestartArgs>) -> String {
        let log = format!("{args:?}");
        let name = args.name.clone();
        run_tool_envelope("restart", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Restart { name: args.name })
                .await;
            annotate_retries(
                format_ack(resp, "restart", format!("restarted {name}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Rebuild a sub-agent: re-applies the current hyperhive flake + agent.nix \
        and restarts the container. No approval required — idempotent. Use when you receive a \
        `needs_update` system event for an agent."
    )]
    async fn update(&self, Parameters(args): Parameters<UpdateArgs>) -> String {
        let log = format!("{args:?}");
        let name = args.name.clone();
        run_tool_envelope("update", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Update { name: args.name })
                .await;
            annotate_retries(
                format_ack(resp, "update", format!("updated {name}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Surface a structured question to either the operator OR a sub-agent. \
        Returns immediately with a question id — do NOT wait inline. When the recipient \
        answers, a system message with event `question_answered { id, question, answer, \
        answerer }` lands in your inbox; handle it on a future turn. \n\n\
        Recipient: omit `to` (or set `to: \"operator\"`) for the human operator on the \
        dashboard. Set `to: \"<agent-name>\"` to ask a sub-agent — they receive a \
        `question_asked` event in their inbox and answer via their `mcp__hyperhive__answer` \
        tool. Useful for delegating decisions / clarifications without losing the \
        question id correlation. \n\n\
        `options` is advisory: pass a short fixed-choice list when applicable, otherwise \
        leave empty for free text. Set `multi: true` to render checkboxes; the answer \
        comes back as a comma-separated string. Set `ttl_seconds` to auto-cancel — on \
        expiry the answer is `[expired]` (with `answerer: \"ttl-watchdog\"`) and the same \
        `question_answered` event fires."
    )]
    async fn ask(&self, Parameters(args): Parameters<AskArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("ask", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Ask {
                    question: args.question,
                    options: args.options,
                    multi: args.multi,
                    ttl_seconds: args.ttl_seconds,
                    to: args.to,
                })
                .await;
            let s = match resp {
                Ok(SocketReply::QuestionQueued(id)) => format!(
                    "question queued (id={id}); answer will arrive as a system \
                     `question_answered` event in your inbox"
                ),
                Ok(SocketReply::Err(m)) => format!("ask failed: {m}"),
                Ok(other) => format!("ask unexpected response: {other:?}"),
                Err(e) => format!("ask transport error: {e:#}"),
            };
            annotate_retries(s, retries)
        })
        .await
    }

    #[tool(
        description = "Answer a question that was routed to the manager via a `question_asked` \
        system event in the manager's inbox (i.e. a sub-agent did `ask(to: \"manager\", \
        ...)`). Pass the `id` from the event and your `answer`. The answer surfaces in the \
        asker's inbox as a `question_answered` event."
    )]
    async fn answer(&self, Parameters(args): Parameters<AnswerArgs>) -> String {
        let log = format!("{args:?}");
        let id = args.id;
        run_tool_envelope("answer", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Answer {
                    id,
                    answer: args.answer,
                })
                .await;
            annotate_retries(
                format_ack(resp, "answer", format!("answered question {id}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Submit a config change for operator approval. Pass the agent name \
        (e.g. `alice` or `hm1nd` for the manager's own config) and a commit sha in that \
        agent's proposed config repo. On approval hive-c0re rebuilds the container."
    )]
    async fn request_apply_commit(
        &self,
        Parameters(args): Parameters<RequestApplyCommitArgs>,
    ) -> String {
        let log = format!("{args:?}");
        let agent = args.agent.clone();
        let commit_ref = args.commit_ref.clone();
        run_tool_envelope("request_apply_commit", log, async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::RequestApplyCommit {
                    agent: args.agent,
                    commit_ref: args.commit_ref,
                    description: args.description,
                })
                .await;
            annotate_retries(
                format_ack(
                    resp,
                    "request_apply_commit",
                    format!("apply approval queued for {agent} @ {commit_ref}"),
                ),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Schedule a reminder that lands in the manager's own inbox at a future \
        time (sender will appear as `reminder`). Use for self-paced manager follow-ups: \
        'recheck pending approval in 10m', 'nudge alice if she hasn't replied by 14:00 \
        UTC'. Set EXACTLY ONE of `delay_seconds` (fire N seconds from now) or \
        `at_unix_timestamp` (fire at absolute epoch second). Body soft-caps at 4 KiB \
        inline — anything larger gets auto-persisted to a file under `/state/reminders/` \
        (the manager's own state mount) and the inbox message becomes a short pointer. \
        Pass `file_path` if you want to control the destination yourself."
    )]
    async fn remind(&self, Parameters(args): Parameters<RemindArgs>) -> String {
        let log = format!("{args:?}");
        run_tool_envelope("remind", log, async move {
            let timing = match (args.delay_seconds, args.at_unix_timestamp) {
                (Some(_), Some(_)) => {
                    return "remind failed: pass exactly one of `delay_seconds` or \
                            `at_unix_timestamp`, not both"
                        .to_string();
                }
                (None, None) => {
                    return "remind failed: pass exactly one of `delay_seconds` or \
                            `at_unix_timestamp`"
                        .to_string();
                }
                (Some(s), None) => hive_sh4re::ReminderTiming::InSeconds { seconds: s },
                (None, Some(t)) => hive_sh4re::ReminderTiming::At { unix_timestamp: t },
            };
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::Remind {
                    message: args.message,
                    timing,
                    file_path: args.file_path,
                })
                .await;
            annotate_retries(format_ack(resp, "remind", "reminder scheduled".to_string()), retries)
        })
        .await
    }

    #[tool(
        description = "Hive-wide loose ends: EVERY pending approval + EVERY unanswered \
        question + EVERY pending reminder across the swarm. Use to scan for stalled \
        coordination — questions sub-agents asked each other that nobody's answering, \
        approvals stuck waiting on the operator, reminders piling up on an offline \
        agent, etc. No args. The sub-agent flavour only returns the agent's own \
        threads; the manager flavour is unfiltered. Cancel any question or reminder \
        row via `cancel_loose_end` (manager bypasses the owner check)."
    )]
    async fn get_loose_ends(&self) -> String {
        run_tool_envelope("get_loose_ends", String::new(), async move {
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::GetLooseEnds)
                .await;
            annotate_retries(format_loose_ends(resp), retries)
        })
        .await
    }

    #[tool(
        description = "Self-introspection for the manager: returns canonical name \
        (`manager`), role (`manager`), and the current hyperhive rev. Same shape as \
        the agent flavour; useful for cross-agent attribution / boot announcements / \
        state-file headers without trusting prompt substitution."
    )]
    async fn whoami(&self) -> String {
        run_tool_envelope("whoami", String::new(), async move {
            let (resp, retries) = self.dispatch(hive_sh4re::ManagerRequest::Whoami).await;
            annotate_retries(format_whoami(resp), retries)
        })
        .await
    }

    #[tool(
        description = "Cancel any open thread in the swarm — a `question` (cancels \
        with the operator-override sentinel so the asker unblocks) or a `reminder` \
        (hard-deleted before fire). `kind` is `\"question\"` or `\"reminder\"`; `id` \
        is the row id from `get_loose_ends` or the original submission reply. \
        Manager surface bypasses the owner check on the sub-agent flavour — use for \
        hive-wide cleanup of stuck or stale threads."
    )]
    async fn cancel_loose_end(&self, Parameters(args): Parameters<CancelLooseEndArgs>) -> String {
        let log = format!("{args:?}");
        let id = args.id;
        run_tool_envelope("cancel_loose_end", log, async move {
            let kind = match parse_loose_end_kind(&args.kind) {
                Ok(k) => k,
                Err(e) => return e,
            };
            let kind_label = loose_end_kind_label(kind);
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::CancelLooseEnd { kind, id })
                .await;
            annotate_retries(
                format_ack(resp, "cancel_loose_end", format!("cancelled {kind_label} {id}")),
                retries,
            )
        })
        .await
    }

    #[tool(
        description = "Fetch recent journal log lines for a sub-agent container. Useful \
        for diagnosing MCP server registration failures, startup crashes, plugin install \
        errors, or any harness issue you can't see from inside the container. `lines` \
        defaults to 50 (max capped at 500 on the host side)."
    )]
    async fn get_logs(&self, Parameters(args): Parameters<GetLogsArgs>) -> String {
        let log = format!("{args:?}");
        let agent = args.agent.clone();
        run_tool_envelope("get_logs", log, async move {
            let lines = args.lines.map(|n| n.min(500));
            let (resp, retries) = self
                .dispatch(hive_sh4re::ManagerRequest::GetLogs {
                    agent: agent.clone(),
                    lines,
                })
                .await;
            let s = match resp {
                Ok(SocketReply::Logs(content)) => {
                    if content.is_empty() {
                        format!("(no journal output for {agent})")
                    } else {
                        content
                    }
                }
                Ok(SocketReply::Err(m)) => format!("get_logs failed: {m}"),
                Ok(other) => format!("get_logs unexpected response: {other:?}"),
                Err(e) => format!("get_logs transport error: {e:#}"),
            };
            annotate_retries(s, retries)
        })
        .await
    }
}

#[tool_handler(
    instructions = "You are the hyperhive manager (hm1nd). You coordinate sub-agents and \
        relay between them and the operator. Use `send` to talk to agents/operator, `recv` \
        to drain your inbox. Privileged: `request_spawn` (new agent, gated on operator \
        approval), `kill` (graceful stop), `request_apply_commit` (config change for \
        any agent including yourself), `ask` (structured question to the operator or a \
        sub-agent — non-blocking, answer arrives later as a `question_answered` event), \
        `answer` (respond to a `question_asked` event directed at you), \
        `get_loose_ends` (hive-wide loose ends — pending approvals + unanswered \
        questions + pending reminders across the swarm), `cancel_loose_end` (cancel any \
        question or reminder row by id), `whoami` (self-introspection — canonical \
        name, role, current hyperhive rev). The manager's own config lives at \
        `/agents/hm1nd/config/agent.nix`."
)]
impl ServerHandler for ManagerServer {}

/// Name of the hyperhive MCP server inside claude's view. Claude prefixes
/// tools as `mcp__<this>__<tool>` (e.g. `mcp__hyperhive__send`).
pub const SERVER_NAME: &str = "hyperhive";

/// Built-in claude tools the turn loop enables via `--tools`. Anything not
/// in this list literally doesn't exist in the session (claude won't even
/// try to call it). Web egress (`WebFetch`/`WebSearch`) and nested agents
/// (`Task`) are intentionally omitted for now; `Bash` is allowed pending a
/// finer-grained allow-list system for shell command patterns. `TodoWrite`
/// is omitted because the todo list lives in claude's in-process session
/// state and silently evaporates on /compact or session reset — agents
/// should plan in /state notes instead. Edit later as our trust model
/// evolves.
pub const ALLOWED_BUILTIN_TOOLS: &[&str] = &["Bash", "Edit", "Glob", "Grep", "Read", "Write"];

/// Which MCP tool surface to advertise via `--allowedTools`. The agent
/// list is the strict subset of the manager list, so we just thread the
/// flavor through.
#[derive(Debug, Clone, Copy)]
pub enum Flavor {
    Agent,
    Manager,
}

/// MCP tools claude is allowed to call without prompting. Mirrors the
/// hyperhive surface so a new tool added in the corresponding `#[tool_router]`
/// impl needs to be listed here too.
#[must_use]
pub fn allowed_mcp_tools(flavor: Flavor) -> Vec<String> {
    let names: &[&str] = match flavor {
        Flavor::Agent => &[
            "send",
            "recv",
            "ask",
            "answer",
            "remind",
            "get_loose_ends",
            "whoami",
            "cancel_loose_end",
        ],
        Flavor::Manager => &[
            "send",
            "recv",
            "request_spawn",
            "kill",
            "start",
            "restart",
            "update",
            "request_apply_commit",
            "ask",
            "answer",
            "get_logs",
            "get_loose_ends",
            "remind",
            "whoami",
            "cancel_loose_end",
        ],
    };
    let mut out: Vec<String> = names
        .iter()
        .map(|t| format!("mcp__{SERVER_NAME}__{t}"))
        .collect();
    // Extra MCP servers declared via `hyperhive.extraMcpServers` in
    // the agent's NixOS config. Each entry maps its `allowedTools`
    // pattern list to `mcp__<server>__<pattern>` so claude can call
    // them without per-tool operator approval. `["*"]` (the default)
    // expands to `mcp__<server>__*` — every tool from that server.
    for (server, spec) in load_extra_mcp() {
        if server == SERVER_NAME {
            continue;
        }
        for pat in spec.allowed_tools {
            out.push(format!("mcp__{server}__{pat}"));
        }
    }
    out
}

/// Combined allow-list passed to `--allowedTools` (auto-approve) — covers
/// both the built-ins and the MCP surface.
#[must_use]
pub fn allowed_tools_arg(flavor: Flavor) -> String {
    let mut all: Vec<String> = ALLOWED_BUILTIN_TOOLS
        .iter()
        .map(|s| (*s).to_owned())
        .collect();
    all.extend(allowed_mcp_tools(flavor));
    all.join(",")
}

/// Built-in tools list for `--tools` (which built-ins exist in this
/// session). Same as `ALLOWED_BUILTIN_TOOLS` but joined comma-separated.
#[must_use]
pub fn builtin_tools_arg() -> String {
    ALLOWED_BUILTIN_TOOLS.join(",")
}

/// Where the NixOS module writes the per-agent extra-MCP spec (see
/// `nix/templates/harness-base.nix`). Each entry becomes an additional
/// `mcpServers.<key>` block in the rendered claude config + a
/// `mcp__<key>__<tool>` pattern in `--allowedTools`.
const EXTRA_MCP_PATH: &str = "/etc/hyperhive/extra-mcp.json";

/// Where the NixOS module writes the per-agent send allow-list (see
/// `nix/templates/harness-base.nix`). Empty list = unrestricted (the
/// default). Non-empty list constrains `mcp__hyperhive__send`'s `to`
/// field; the manager is always implicitly permitted regardless of
/// the list contents.
const SEND_ALLOW_PATH: &str = "/etc/hyperhive/send-allow.json";

/// Enforce the per-agent send allow-list. Returns `Ok` when the
/// recipient is permitted (no list configured, manager always
/// allowed, or `to` is in the list); returns `Err(refusal)` with a
/// claude-readable string when blocked — the harness surfaces the
/// refusal as the tool result so claude knows the message didn't
/// land and can react (e.g. route via the manager instead).
fn check_send_allowed(to: &str) -> Result<(), String> {
    if to == hive_sh4re::MANAGER_AGENT {
        // Always allow agents to talk to the manager — otherwise a
        // misconfigured allow-list could leave a sub-agent unable
        // to ask for help.
        return Ok(());
    }
    let Ok(raw) = std::fs::read_to_string(SEND_ALLOW_PATH) else {
        return Ok(()); // file missing → no policy configured → unrestricted
    };
    let allow: Vec<String> = match serde_json::from_str(&raw) {
        Ok(v) => v,
        Err(e) => {
            tracing::warn!(
                path = SEND_ALLOW_PATH,
                error = ?e,
                "send allow-list parse failed; falling back to unrestricted",
            );
            return Ok(());
        }
    };
    if allow.is_empty() {
        return Ok(()); // empty list = unrestricted (back-compat)
    }
    if allow.iter().any(|n| n == to) {
        return Ok(());
    }
    Err(format!(
        "send refused: recipient '{to}' not in hyperhive.allowedRecipients \
         (configured in agent.nix). Allowed: {allow:?}. The manager is \
         always reachable — route through `send(to: \"manager\", …)` if \
         you need to reach someone outside the allow-list."
    ))
}

#[derive(Debug, serde::Deserialize)]
struct ExtraMcpServer {
    command: String,
    #[serde(default)]
    args: Vec<String>,
    #[serde(default)]
    env: std::collections::BTreeMap<String, String>,
    #[serde(default = "default_allowed_tools")]
    #[serde(rename = "allowedTools")]
    allowed_tools: Vec<String>,
}

fn default_allowed_tools() -> Vec<String> {
    vec!["*".to_owned()]
}

/// Read + parse the extra-MCP spec. Returns an empty map on missing /
/// unparsable file (the agent has none configured, or the file is
/// malformed — both cases degrade to "no extra servers").
fn load_extra_mcp() -> std::collections::BTreeMap<String, ExtraMcpServer> {
    let Ok(raw) = std::fs::read_to_string(EXTRA_MCP_PATH) else {
        return std::collections::BTreeMap::new();
    };
    serde_json::from_str(&raw).unwrap_or_else(|e| {
        tracing::warn!(
            path = EXTRA_MCP_PATH,
            error = ?e,
            "extra-mcp spec parse failed; ignoring",
        );
        std::collections::BTreeMap::new()
    })
}

/// Render the MCP config blob claude reads from `--mcp-config <path>`.
/// `agent_binary` is the path (or PATH-resolvable name) of the `hive-ag3nt`
/// executable; `socket` is the hyperhive per-agent socket bind-mounted into
/// the container (forwarded to the child as `--socket <path>`). Merges in
/// any extra MCP servers declared via `hyperhive.extraMcpServers` in the
/// agent's NixOS config.
#[must_use]
pub fn render_claude_config(agent_binary: &str, socket: &std::path::Path) -> String {
    let mut servers = serde_json::Map::new();
    servers.insert(
        SERVER_NAME.to_owned(),
        serde_json::json!({
            "command": agent_binary,
            "args": ["--socket", socket.display().to_string(), "mcp"],
            "env": {}
        }),
    );
    for (name, spec) in load_extra_mcp() {
        if name == SERVER_NAME {
            tracing::warn!(
                "extra MCP server name `{SERVER_NAME}` collides with the built-in surface; ignoring",
            );
            continue;
        }
        servers.insert(
            name,
            serde_json::json!({
                "command": spec.command,
                "args": spec.args,
                "env": spec.env,
            }),
        );
    }
    let config = serde_json::json!({ "mcpServers": servers });
    serde_json::to_string_pretty(&config).unwrap_or_else(|_| "{}".into())
}