//! Manager socket — `/run/hyperhive/manager/mcp.sock` on the host,
//! bind-mounted into the manager container at `/run/hive/mcp.sock`.
//! Reserved recipient names/senders, the out-of-band `HelperEvent`
//! payload hive-c0re pushes into the manager's inbox, and the
//! schedule-prompt submission payload.

use hive_types::Ident;
use serde::{Deserialize, Serialize};

use crate::approvals::ApprovalStatus;

/// Logical name the broker uses for the manager.
pub const MANAGER_AGENT: &str = "ruth";

/// Logical name the broker uses for the human operator. Messages with
/// `to = OPERATOR_RECIPIENT` accumulate in sqlite and surface on the
/// dashboard's inbox view — they are never `recv`'d by an agent harness.
pub const OPERATOR_RECIPIENT: &str = "operator";

/// Reserved magic recipient — `send(to: "<parent>", ...)` is rewritten
/// by hive-c0re at delivery time to whoever `topology::parent_of(sender)`
/// returns, or to [`OPERATOR_RECIPIENT`] when the sender is a root agent
/// (no parent). Lets agents address their parent without hardcoding the
/// label, so runtime reparenting requires no agent-side restart. The
/// angle brackets are not valid in agent names (validators reject
/// `<`/`>`), so this name can never collide with a real recipient.
pub const PARENT_RECIPIENT: &str = "<parent>";

/// Reserved magic recipient — `send(to: "<children>", ...)` fans out to
/// every agent whose direct parent (per `topology.json`) is the sender.
/// Lets a sub-manager nudge its subtree without enumerating labels at
/// call-time; topology changes propagate for free. The angle brackets
/// are structurally safe — agent name validation rejects `<`/`>`.
/// Delivers to an empty set (no-op) for leaf agents that have no children.
pub const CHILDREN_RECIPIENT: &str = "<children>";

/// Sender hive-c0re uses for events it pushes into the manager's inbox.
/// Manager harness recognises this and parses the body as a `HelperEvent`.
pub const SYSTEM_SENDER: &str = "system";

/// Parse `s` as a [`Ident`] for use as `Message.from`, falling back to
/// [`SYSTEM_SENDER`] on the (should-be-unreachable) case that `s` isn't
/// ident-shaped. `Message.from` is always either a fixed sentinel literal
/// (`SYSTEM_SENDER`, `OPERATOR_RECIPIENT`, `"scheduled"`, …) or an
/// already-registered agent's own name reaching this point through
/// hive-c0re's internal dispatch — never arbitrary external input — so
/// this is a defensive fallback for a programming-bug case, not a
/// validation gate.
///
/// # Panics
///
/// Never, unless [`SYSTEM_SENDER`] itself stops being ident-shaped (which
/// would also be a programming bug, caught by `hive-types`' own tests).
#[must_use]
pub fn trusted_sender(s: &str) -> Ident {
    Ident::parse(s)
        .unwrap_or_else(|_| Ident::parse(SYSTEM_SENDER).expect("SYSTEM_SENDER is a valid Ident"))
}

/// Out-of-band events the host-side daemon pushes to the manager's inbox.
/// Serialised as JSON in `Message::body` (sender = `SYSTEM_SENDER`).
/// Per-variant triggers + the optional `sha`/`tag` semantics live in
/// `docs/approvals.md::Helper events to the manager`.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "event", rename_all = "snake_case")]
pub enum HelperEvent {
    /// An approval transitioned to a terminal state.
    ApprovalResolved {
        id: i64,
        agent: String,
        commit_ref: String,
        status: ApprovalStatus,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        note: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        sha: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        tag: Option<String>,
    },
    /// A sub-agent's recorded flake rev is stale relative to hyperhive.
    NeedsUpdate { agent: String },
    /// Container exited without an operator-initiated stop (crash).
    ContainerCrash {
        agent: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        note: Option<String>,
    },
}

/// Submission payload for `RequestSchedulePrompt`. Lives outside the
/// enum so it can also serialize into the approval row's `commit_ref`
/// (the dispatcher re-parses it on approve and inserts the schedule).
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct SchedulePromptPayload {
    /// Names of recipient agents. Operator + `root` allowed.
    pub targets: Vec<String>,
    /// Message body delivered to each target's inbox at fire time.
    /// Same size budget as `Send.body` — soft cap at the broker level.
    pub body: String,
    /// Absolute unix timestamp (seconds) for the FIRST fire. For
    /// recurring schedules the worker then re-arms in
    /// `interval_seconds` steps.
    pub first_fire_at_unix: i64,
    /// `None` = one-shot. `Some(n > 0)` = recurring every `n` seconds.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub interval_seconds: Option<u64>,
    /// Optional description shown on the dashboard approval card AND
    /// stored on the resulting schedule row for the operator's
    /// "what is this?" reference later.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
}

#[cfg(test)]
mod reserved_name_tests {
    use super::{
        CHILDREN_RECIPIENT, MANAGER_AGENT, OPERATOR_RECIPIENT, PARENT_RECIPIENT, SYSTEM_SENDER,
    };
    use hive_types::{Ident, RESERVED_NAMES_ENV, is_reserved_name};

    /// The blacklist as nix rendered it for this test run.
    ///
    /// **Panics when the variable is absent, deliberately.** The list lives
    /// in `nix/reserved-names.nix` now, so this test can no longer read it
    /// from the Rust tree; `nix/checks.nix` and `nix/devshell.nix` both
    /// export it. Skipping instead would turn "nobody wired the variable"
    /// into a green run — the same shape as a checker that reports clean
    /// because it crashed, and the whole point of a drift test is that it
    /// is the thing that notices.
    fn reserved() -> Vec<String> {
        let raw = hive_types::reserved_names_raw().unwrap_or_else(|| {
            panic!(
                "{RESERVED_NAMES_ENV} is unset or blank, so the drift test cannot run. \
                 nix/checks.nix and nix/devshell.nix are supposed to export it from \
                 nix/reserved-names.nix — fix the plumbing rather than this test."
            )
        });
        hive_types::parse_reserved_names(&raw)
            .into_iter()
            .map(str::to_owned)
            .collect()
    }

    /// The sentinels declared here and the blacklist nix owns are two
    /// spellings of one fact, in places that cannot import each other's
    /// intent. This pins them together: adding a sentinel without reserving
    /// it now fails here rather than years later, when an agent takes the
    /// name.
    #[test]
    fn ident_shaped_sentinels_are_reserved() {
        let owned = reserved();
        let reserved: Vec<&str> = owned.iter().map(String::as_str).collect();
        for sentinel in [OPERATOR_RECIPIENT, SYSTEM_SENDER] {
            assert!(
                is_reserved_name(sentinel, &reserved),
                "{sentinel:?} is a sentinel an agent could be named — it must be in \
                 nix/reserved-names.nix"
            );
        }
    }

    /// Every entry nix hands us must be a name an agent could actually have
    /// been given. One that `Ident::parse` rejects is dead weight — nothing
    /// could ever have been created with it, so listing it implies a guard
    /// doing nothing. `graceful-stop` is what makes this worth asserting: it
    /// is hyphenated, and a charset tightening would silently retire it.
    ///
    /// This assertion used to live beside the list in `hive-types`; it moved
    /// here because here is where the real list is readable.
    #[test]
    fn every_reserved_name_is_a_valid_ident() {
        let owned = reserved();
        assert!(
            !owned.is_empty(),
            "the blacklist rendered empty — an empty list makes every assertion below vacuous"
        );
        for name in &owned {
            assert!(
                Ident::parse(name).is_ok(),
                "{name:?} is reserved but not a parseable ident — one of the two is wrong"
            );
        }
    }

    /// The other half, and the reason the test above is not vacuous: these
    /// sentinels are *unreachable* as agent names because the charset
    /// rejects them, so they are correctly absent from the list. If a
    /// charset change ever made one parseable, it would become a real
    /// collision and this test is what notices.
    #[test]
    fn bracketed_recipients_cannot_be_agent_names() {
        let owned = reserved();
        let reserved: Vec<&str> = owned.iter().map(String::as_str).collect();
        for sentinel in [PARENT_RECIPIENT, CHILDREN_RECIPIENT] {
            assert!(
                Ident::parse(sentinel).is_err(),
                "{sentinel:?} parses as an ident now — it is reachable as an agent name and must be reserved"
            );
            assert!(!is_reserved_name(sentinel, &reserved));
        }
    }

    /// `ruth` is a real agent, not a protocol literal, so it is not
    /// reserved: a second agent wanting the name is a *taken* name, which
    /// the roster check answers. Recorded as a test so the distinction is
    /// enforced rather than remembered.
    #[test]
    fn manager_name_is_taken_not_reserved() {
        let owned = reserved();
        let reserved: Vec<&str> = owned.iter().map(String::as_str).collect();
        assert!(Ident::parse(MANAGER_AGENT).is_ok());
        assert!(!is_reserved_name(MANAGER_AGENT, &reserved));
    }
}