//! Shared dispatch helpers for the `Ask` / `Answer` flow. Both the
//! agent socket and the manager socket call into here so the routing
//! semantics — recipient = operator vs. peer agent, answerer
//! authorisation, asker-notification — only live in one place.
//!
//! Routing rules at a glance:
//!
//! - `Ask { to: None | Some("operator") }` → stored with `target = NULL`;
//!   the dashboard's `pending()` query surfaces it; operator answers
//!   via the dashboard.
//! - `Ask { to: Some(<agent>) }` → stored with `target = <agent>`;
//!   a `HelperEvent::QuestionAsked` is pushed into `<agent>`'s
//!   inbox so they can `Answer { id, answer }` on their own socket.
//! - `Answer { id, answer }` → permission-checked in
//!   `OperatorQuestions::answer` (only the target agent or the
//!   operator can answer; both paths fire the same
//!   `QuestionAnswered` event to the asker).

use std::sync::Arc;

use crate::coordinator::Coordinator;
use crate::limits;
use crate::socket_server::spawn_question_watchdog;

/// Cap on how long an asker can demand an answer before the watchdog
/// auto-resolves with `[expired]`. Six hours mirrors typical agent
/// session lifetimes — beyond that an unanswered question is
/// effectively a dead thread and should be re-asked, not blocked on.
const MAX_TTL_SECONDS: u64 = 6 * 60 * 60;

/// Handle either surface's `Ask` request. Returns the queued
/// question id on success or a caller-ready error string. Caller is
/// responsible for wrapping in the matching `*Response::Err` /
/// `QuestionQueued` variant.
pub fn handle_ask(
    coord: &Arc<Coordinator>,
    asker: &str,
    question: &str,
    options: &[String],
    multi: bool,
    ttl_seconds: Option<u64>,
    to: Option<&str>,
) -> Result<i64, String> {
    limits::check_size("question", question)?;
    // Normalise `Some("operator")` → None so the storage layer
    // only has to think about NULL vs. non-NULL targets, not
    // "is this string the operator?".
    let target = match to {
        None => None,
        Some(t) if t == hive_sh4re::manager::OPERATOR_RECIPIENT => None,
        Some("") => {
            return Err("ask: `to` cannot be empty (omit it for the operator path)".to_owned());
        }
        Some(t) if t == asker => {
            return Err("ask: cannot ask yourself a question (would loop forever)".to_owned());
        }
        Some(t) => Some(t),
    };
    let ttl = ttl_seconds.map(|s| s.min(MAX_TTL_SECONDS));
    let deadline_at = ttl.and_then(|s| {
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .ok()
            .and_then(|d| i64::try_from(d.as_secs()).ok())
            .unwrap_or(0);
        i64::try_from(s).ok().map(|s| now + s)
    });
    let id = coord
        .questions
        .submit(asker, question, options, multi, deadline_at, target)
        .map_err(|e| format!("{e:#}"))?;
    tracing::info!(%id, %asker, ?target, ?deadline_at, "question queued");
    // Agent-targeted questions need to wake the recipient — drop a
    // QuestionAsked event into their inbox so the answerer doesn't
    // have to poll. Operator-targeted questions show up on the
    // dashboard's pending pane via `pending()` instead, plus a
    // `QuestionAdded` dashboard event so the browser updates live.
    if let Some(target_agent) = target {
        coord.notify_agent(
            target_agent,
            &hive_sh4re::manager::HelperEvent::QuestionAsked {
                id,
                asker: asker.to_owned(),
                question: question.to_owned(),
                options: options.to_vec(),
                multi,
            },
        );
    }
    // Always fire on the dashboard channel — both operator-targeted
    // and peer threads now surface in the dashboard's questions pane.
    coord.emit_question_added(&crate::coordinator::QuestionAdded {
        id,
        asker,
        question,
        options,
        multi,
        deadline_at,
        target,
    });
    if let Some(t) = ttl {
        spawn_question_watchdog(coord, id, t);
    }
    Ok(id)
}

/// Handle either surface's `Answer` request. Returns `Ok(())` on
/// success or a caller-ready error string. Authorisation lives in
/// `OperatorQuestions::answer` — we only have to wire the result
/// back to the asker as a `QuestionAnswered` event.
pub fn handle_answer(
    coord: &Arc<Coordinator>,
    answerer: &str,
    id: i64,
    answer: &str,
) -> Result<(), String> {
    limits::check_size("answer", answer)?;
    let (question, asker, target) = coord
        .questions
        .answer(id, answer, answerer)
        .map_err(|e| format!("{e:#}"))?;
    tracing::info!(%id, %answerer, %asker, "question answered");
    // Use answerer as the broker `from` so the asker's terminal shows
    // the real name (agent or "operator") instead of "system".
    coord.notify_agent_from(
        answerer,
        &asker,
        &hive_sh4re::manager::HelperEvent::QuestionAnswered {
            id,
            question,
            answer: answer.to_owned(),
            answerer: answerer.to_owned(),
        },
    );
    // Dashboard surfaces both operator-targeted and peer threads;
    // emit unconditionally so the derived store moves the row.
    // `cancelled = false` because this path is a real answer (the
    // operator-cancel button goes through `post_cancel_question`).
    coord.emit_question_resolved(id, answer, answerer, false, target.as_deref());
    Ok(())
}

/// Handle `CancelLooseEnd` from a per-agent socket. Dispatches by kind, each
/// with its own auth check: question / reminder cancels are ownership-only
/// (an agent cancels its own), and approval cancels require the `approvals`
/// tool-group (the grantable capability) AND ownership — the canceller must
/// be the approval's submitter — so no positional / hardcoded privilege and
/// no cross-agent cancellation. (The operator's cancel-anything path is a
/// separate handler.)
/// On question cancel, fires the `QuestionAnswered` event back to the asker
/// so the harness loop can react (mirrors the operator-cancel dashboard path).
pub fn handle_cancel_loose_end(
    coord: &Arc<Coordinator>,
    canceller: &str,
    kind: hive_sh4re::inbox::CancelLooseEndKind,
    id: i64,
) -> Result<(), String> {
    match kind {
        hive_sh4re::inbox::CancelLooseEndKind::Question => {
            // Agent-socket path: never privileged — an agent may only cancel
            // its own question (ownership). The operator's cancel-anything
            // path goes through a separate handler with `privileged = true`.
            let (question, asker, target) = coord
                .questions
                .cancel(id, canceller, false)
                .map_err(|e| format!("{e:#}"))?;
            let sentinel = format!("[cancelled by {canceller}]");
            tracing::info!(%id, %canceller, %asker, "question cancelled");
            // Only notify the asker if they didn't cancel it themselves.
            // Self-cancels are already known to the canceller — sending
            // a QuestionAnswered back would cause the harness to process
            // its own cancel as an incoming answer.
            if asker != canceller {
                coord.notify_agent_from(
                    canceller,
                    &asker,
                    &hive_sh4re::manager::HelperEvent::QuestionAnswered {
                        id,
                        question,
                        answer: sentinel.clone(),
                        answerer: canceller.to_owned(),
                    },
                );
            }
            coord.emit_question_resolved(id, &sentinel, canceller, true, target.as_deref());
            Ok(())
        }
        hive_sh4re::inbox::CancelLooseEndKind::Reminder => {
            // Reminders are now agent-local (in-container store) — the
            // agent-mcp `cancel_loose_end` tool branches on this kind and
            // dials the agent's own socket directly, never forwarding to
            // hive-c0re. This arm should be unreachable in practice; kept
            // only so the match stays exhaustive.
            Err(format!(
                "reminder {id}: reminders are handled locally by the agent, \
                 not by hive-c0re"
            ))
        }
        hive_sh4re::inbox::CancelLooseEndKind::Approval => {
            // Withdrawing an approval needs the grantable `approvals`
            // tool-group (held by any approval-submitting orchestrator)
            // AND ownership: only the agent that submitted the approval
            // may withdraw it. Without the ownership check, any
            // approvals-group agent could cancel any other's approval by
            // id. A NULL submitter (legacy row predating the column) is
            // treated as operator-initiated (no agent tracking predates
            // the column).
            check_can_cancel_approval(canceller)?;
            let submitter = coord
                .approvals
                .submitter_of(id)
                .map_err(|e| format!("{e:#}"))?
                .unwrap_or_else(|| "operator".to_owned());
            if submitter != canceller {
                return Err(format!(
                    "cancel_loose_end: approval {id} was submitted by {submitter}, \
                     not {canceller}; only the submitting agent can withdraw it"
                ));
            }
            let approval = coord
                .approvals
                .mark_cancelled(id, canceller)
                .map_err(|e| format!("{e:#}"))?;
            tracing::info!(%id, %canceller, agent = %approval.agent, "approval cancelled");
            let sha_short = approval
                .fetched_sha
                .as_deref()
                .map(|s| s[..s.len().min(12)].to_owned());
            coord.emit_approval_resolved(crate::coordinator::ApprovalResolved {
                id: approval.id,
                agent: approval.agent.as_str(),
                approval_kind: approval.kind.as_str(),
                sha_short,
                status: "cancelled",
                note: approval.note,
                description: approval.description,
            });
            Ok(())
        }
    }
}

/// Capability guard on the `Approval` cancel arm: the caller must hold the
/// `approvals` tool-group (the grantable capability for approval-submitting
/// orchestrators), checked server-side via `tool_groups::groups_for`. Pulled
/// out so the auth check has its own focused unit test — exercising the full
/// `handle_cancel_loose_end` flow would need a `Coordinator` fixture (broker +
/// sqlite + in-memory questions) we don't have. Keys on a grantable capability,
/// not a positional / hardcoded privilege.
fn check_can_cancel_approval(canceller: &str) -> Result<(), String> {
    const APPROVALS_GROUP: &str = "approvals";
    if crate::tool_groups::groups_for(canceller)
        .iter()
        .any(|g| g == APPROVALS_GROUP)
    {
        Ok(())
    } else {
        Err(
            "cancel_loose_end: cancelling approval rows requires the `approvals` tool group"
                .to_owned(),
        )
    }
}

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

    #[test]
    fn approval_cancel_rejects_callers_without_the_approvals_group() {
        // A caller that doesn't hold the `approvals` tool-group must not be
        // able to cancel approval rows even if it invents an id. The guard is
        // server-side so client cooperation is irrelevant — and it keys on a
        // grantable capability (the tool-group), not on any agent name.
        // `groups_for` of a name with no tool_groups.json entry is empty.
        let err = check_can_cancel_approval("nobody-with-no-groups").unwrap_err();
        assert!(err.contains("approvals` tool group"), "{err}");
    }
}

// Real coverage needs a `Coordinator` fixture (broker + sqlite +
// in-memory questions). Skipped for now — the normalisation branches
// in `handle_ask` are short enough to read line-by-line; once we add
// a coord test harness, drop integration tests here for: self-target
// rejection, operator-string passthrough, agent-to-agent QuestionAsked
// emission, and `Answer` authorisation.