//! Scheduled-prompt list + rebuild-queue cancel endpoints for the dashboard.
//!
//! `/api/schedules` is read-only: it lists the rows still in the hive's
//! `scheduled_prompts` table so the operator can recreate them with
//! `swarmctl schedule` (`docs/swarm/schedules.md`). Nothing on the hive
//! writes or fires those rows. Also the co-located
//! `/api/rebuild-queue/{id}/cancel` endpoint.

use axum::{
    extract::{Path as AxumPath, State},
    response::{IntoResponse, Response},
};

use super::{AppState, error_response};

#[derive(serde::Serialize, utoipa::ToSchema)]
pub(super) struct CancelResultBody {
    cancelled: bool,
}

/// Snapshot of every schedule row for the
/// scheduled-prompts tab.
///
/// Returns the wire shape directly so the frontend can render
/// without an extra translation layer.
// `hive_sh4re::schedule::WireSchedule` (the actual body) has no `ToSchema` — adding
// one would pull `utoipa` into the wire-types crate for a single dashboard
// endpoint. `serde_json::Value` placeholder.
#[utoipa::path(
    get,
    path = "/api/schedules",
    responses(
        (status = 200, description = "every schedule, wire shape", body = Vec<serde_json::Value>),
        (status = 500, description = "sqlite read failed"),
    ),
    tag = "schedules"
)]
pub(super) async fn api_schedules(State(state): State<AppState>) -> Response {
    match state.coord.scheduled_prompts.list() {
        Ok(rows) => {
            let mut wire: Vec<hive_sh4re::schedule::WireSchedule> =
                rows.into_iter().map(schedule_to_wire).collect();
            let live: std::collections::HashSet<String> = state
                .coord
                .containers_snapshot()
                .await
                .into_iter()
                .map(|c| c.name)
                .collect();
            filter_ghost_schedule_targets(&mut wire, &live);
            axum::Json(wire).into_response()
        }
        Err(e) => error_response(&format!("scheduled_prompts list: {e:#}")),
    }
}

/// Drop schedule targets that point at agents which no longer exist, so
/// the schedule table doesn't render ghost columns for destroyed agents.
/// `live` is the set of logical agent names from the last
/// `nixos-container list` scan (stopped agents included, destroyed ones
/// absent). A view filter: the rows keep every target.
fn filter_ghost_schedule_targets(
    schedules: &mut [hive_sh4re::schedule::WireSchedule],
    live: &std::collections::HashSet<String>,
) {
    for s in schedules.iter_mut() {
        s.targets.retain(|t| live.contains(&t.target));
    }
}

fn schedule_to_wire(s: crate::scheduled_prompts::Schedule) -> hive_sh4re::schedule::WireSchedule {
    hive_sh4re::schedule::WireSchedule {
        id: s.id,
        owner: s.owner,
        body: s.body,
        interval_seconds: s.interval_seconds,
        next_fire_at_unix: s.next_fire_at_unix,
        created_at_unix: s.created_at_unix,
        source: match s.source {
            crate::scheduled_prompts::ScheduleSource::Operator => {
                hive_sh4re::schedule::WireScheduleSource::Operator
            }
            crate::scheduled_prompts::ScheduleSource::Approval { id } => {
                hive_sh4re::schedule::WireScheduleSource::Approval { id }
            }
        },
        cancelled_at_unix: s.cancelled_at_unix,
        paused_at_unix: s.paused_at_unix,
        description: s.description,
        targets: s
            .targets
            .into_iter()
            .map(|t| hive_sh4re::schedule::WireScheduleTarget {
                target: t.target,
                cancelled_at_unix: t.cancelled_at_unix,
                last_fired_at_unix: t.last_fired_at_unix,
                last_result: t.last_result,
            })
            .collect(),
    }
}

/// Drop still-queued work from the job
/// queue.
///
/// `id` is a **node** id. A DAG's root cancels the whole group (the scheduler
/// cascades to pending descendants), which is what the dashboard's cancel
/// button sends today — a DAG id *is* its root node's id. An interior node
/// cancels just that branch.
///
/// Refuses `Running` / terminal nodes: an
/// in-flight node owns the agent's nix store + nixos-container update
/// lock and can't be safely interrupted from the queue side. Always
/// returns 200; the body is `{"cancelled": true}` on a successful
/// flip to Cancelled, `{"cancelled": false}` when the DAG was
/// Running / terminal / gone. On success a fresh `RebuildQueueChanged`
/// snapshot fires so the state flip surfaces live.
#[utoipa::path(
    post,
    path = "/api/rebuild-queue/{id}/cancel",
    params(("id" = u64, Path, description = "job-queue node id (a DAG's root cancels the group)")),
    responses((status = 200, description = "whether the DAG was cancelled", body = CancelResultBody)),
    tag = "schedules"
)]
pub(super) async fn post_rebuild_queue_cancel(
    State(state): State<AppState>,
    AxumPath(id): AxumPath<u64>,
) -> Response {
    if state.coord.job_queue.cancel(id) {
        // Any terminal side effect is the DAG's own spared tail node, which the
        // scheduler picks up on its next pass — nothing to fire from here.
        state.coord.emit_rebuild_queue_snapshot();
        axum::Json(CancelResultBody { cancelled: true }).into_response()
    } else {
        axum::Json(CancelResultBody { cancelled: false }).into_response()
    }
}

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

    fn target(name: &str) -> hive_sh4re::schedule::WireScheduleTarget {
        hive_sh4re::schedule::WireScheduleTarget {
            target: name.to_owned(),
            cancelled_at_unix: None,
            last_fired_at_unix: None,
            last_result: None,
        }
    }

    fn schedule(targets: &[&str]) -> hive_sh4re::schedule::WireSchedule {
        hive_sh4re::schedule::WireSchedule {
            id: 1,
            owner: "operator".to_owned(),
            body: "ping".to_owned(),
            interval_seconds: None,
            next_fire_at_unix: hive_sh4re::wire_time::from_secs(0),
            created_at_unix: hive_sh4re::wire_time::from_secs(0),
            source: hive_sh4re::schedule::WireScheduleSource::Operator,
            cancelled_at_unix: None,
            paused_at_unix: None,
            description: None,
            targets: targets.iter().map(|t| target(t)).collect(),
        }
    }

    #[test]
    fn ghost_filter_drops_dead_agents_keeps_live() {
        let live: std::collections::HashSet<String> = ["iris".to_owned(), "damocles".to_owned()]
            .into_iter()
            .collect();
        let mut schedules = vec![schedule(&["iris", "ghost", "damocles"])];
        filter_ghost_schedule_targets(&mut schedules, &live);
        let kept: Vec<&str> = schedules[0]
            .targets
            .iter()
            .map(|t| t.target.as_str())
            .collect();
        assert_eq!(kept, vec!["iris", "damocles"]);
    }

    #[test]
    fn ghost_filter_can_empty_targets_when_all_dead() {
        let live: std::collections::HashSet<String> = std::collections::HashSet::new();
        let mut schedules = vec![schedule(&["gone1", "gone2"])];
        filter_ghost_schedule_targets(&mut schedules, &live);
        assert!(schedules[0].targets.is_empty());
    }
}