//! Stats + loose-ends + todos read endpoints.

use axum::extract::State;
use axum::response::{IntoResponse, Response};
use serde::Deserialize;

use super::AppState;

#[derive(Deserialize)]
pub(super) struct StatsQuery {
    window: Option<String>,
}

pub(super) async fn api_stats(
    State(_state): State<AppState>,
    axum::extract::Query(q): axum::extract::Query<StatsQuery>,
) -> axum::Json<crate::stats::Snapshot> {
    let window = crate::stats::Window::parse(q.window.as_deref().unwrap_or("24h"));
    let mut snapshot = crate::stats::snapshot_default(window);
    // Pass the window span so the local reminder rollup filters its counts
    // to the same time range as the chart data.
    let window_secs = window.span_secs();
    let window_secs_u = u64::try_from(window_secs).unwrap_or(0);
    snapshot.reminder_stats = fetch_reminder_stats(window_secs_u).await;
    axum::Json(snapshot)
}

/// Fetch reminder activity stats from the harness-local reminder store over
/// `HIVE_AGENT_SOCKET` (#2635 inc 1 — was a broker RPC before reminders
/// moved in-container). Returns `None` on any transport / decode failure or
/// when the socket is unset — the stats are decorative, not authoritative.
async fn fetch_reminder_stats(window_secs: u64) -> Option<hive_sh4re::ReminderStats> {
    use tokio::io::{AsyncBufReadExt as _, AsyncWriteExt as _, BufReader};
    use tokio::net::UnixStream;

    let socket_path = std::env::var_os("HIVE_AGENT_SOCKET").map(std::path::PathBuf::from)?;
    if !socket_path.exists() {
        return None;
    }
    tokio::time::timeout(std::time::Duration::from_secs(3), async move {
        let mut stream = UnixStream::connect(&socket_path).await?;
        let req = hive_agent_sock::Request::ReminderRollup {
            since_secs: window_secs,
        };
        let mut line = serde_json::to_string(&req)?;
        line.push('\n');
        stream.write_all(line.as_bytes()).await?;
        stream.flush().await?;
        let mut lines = BufReader::new(stream).lines();
        let resp_line = lines
            .next_line()
            .await?
            .ok_or_else(|| anyhow::anyhow!("agent socket closed without response"))?;
        let resp: hive_agent_sock::Response = serde_json::from_str(&resp_line)?;
        anyhow::Ok(match resp {
            hive_agent_sock::Response::ReminderRollup { stats } => Some(stats),
            _ => None,
        })
    })
    .await
    .ok()?
    .ok()
    .flatten()
}

/// `GET /api/todos` — snapshot of this agent's local todos (loose-ends v2).
///
/// Connects to the in-agent harness socket (`HIVE_AGENT_SOCKET`) and calls
/// `ListTodos`. Returns `{ "todos": [...] }` where each entry is a
/// `LooseEnd::Todo` (subsystem, key, summary, source, `age_seconds`). Returns
/// an empty array when the socket is unavailable — best-effort, silent failure.
pub(super) async fn api_todos() -> Response {
    use tokio::io::{AsyncBufReadExt as _, AsyncWriteExt as _, BufReader};
    use tokio::net::UnixStream;

    let socket_path = match std::env::var_os("HIVE_AGENT_SOCKET") {
        Some(p) => std::path::PathBuf::from(p),
        None => return axum::Json(serde_json::json!({ "todos": [] })).into_response(),
    };
    if !socket_path.exists() {
        return axum::Json(serde_json::json!({ "todos": [] })).into_response();
    }
    let todos = tokio::time::timeout(std::time::Duration::from_secs(3), async move {
        let mut stream = UnixStream::connect(&socket_path).await?;
        let req = hive_agent_sock::Request::ListTodos { subsystem: None };
        let mut line = serde_json::to_string(&req)?;
        line.push('\n');
        stream.write_all(line.as_bytes()).await?;
        stream.flush().await?;
        let mut lines = BufReader::new(stream).lines();
        let resp_line = lines
            .next_line()
            .await?
            .ok_or_else(|| anyhow::anyhow!("agent socket closed without response"))?;
        let resp: hive_agent_sock::Response = serde_json::from_str(&resp_line)?;
        anyhow::Ok(match resp {
            hive_agent_sock::Response::LooseEnds { loose_ends } => loose_ends,
            _ => Vec::new(),
        })
    })
    .await
    .unwrap_or_else(|_| Err(anyhow::anyhow!("timeout")))
    .unwrap_or_default();
    axum::Json(serde_json::json!({ "todos": todos })).into_response()
}