//! Shared in-container filesystem-path resolution.
//!
//! Every process that runs inside an agent container - the harness plus
//! the out-of-process MCP daemons (bash, matrix, ...) - must resolve the
//! harness directory layout identically. These helpers live here so the
//! resolution exists in exactly one place rather than being mirrored
//! across crates.

use std::path::PathBuf;

/// Base harness directory for the current agent. Uses `HYPERHIVE_HARNESS_DIR`
/// if set (injected by the hive-c0re meta flake after the harness/state
/// split). For pre-split / dev deployments where it isn't set, falls back to
/// a `harness/` sibling of `HYPERHIVE_STATE_DIR`, and finally to
/// `/agents/{HIVE_LABEL}/harness` when neither dir env var is present — the
/// shape the harness derives from its label alone.
#[must_use]
pub fn harness_dir() -> PathBuf {
    if let Some(p) = std::env::var_os("HYPERHIVE_HARNESS_DIR") {
        return PathBuf::from(p);
    }
    if let Some(state) = std::env::var_os("HYPERHIVE_STATE_DIR") {
        let state_path = PathBuf::from(&state);
        if let Some(parent) = state_path.parent() {
            return parent.join("harness");
        }
    }
    let label = std::env::var("HIVE_LABEL").unwrap_or_default();
    PathBuf::from(format!("/agents/{label}/harness"))
}

/// File name of the pause marker inside the harness dir. Re-exported from
/// `hive-priv-sock`, which owns the definition because hive-priv (root) is
/// the component that actually creates and unlinks the marker — hive-c0re
/// runs unprivileged and cannot write to the agent-owned harness dir — and
/// hive-priv deliberately does not depend on this crate. Shared so the
/// in-container resolver below, hive-c0re's host-side one (which builds the
/// same path from `/var/lib/hyperhive/agents/{name}/harness`) and the
/// privileged writer cannot drift apart.
pub use hive_priv_sock::PAUSED_MARKER_FILE;

/// Marker file whose presence means "this agent is paused": the harness
/// keeps serving its web UI and MCP daemons but drives no turns, so
/// inbox messages queue up unacked until it's removed.
///
/// It lives in the harness dir rather than `state/` because `state/` is
/// the agent's own scratch space — this is harness control state. The
/// harness dir is bind-mounted from the host, so the marker is the
/// single source of truth for both sides: the harness stats it to gate
/// the turn loop, and hive-c0re stats it to render the paused
/// indicator and creates/removes it for `hivectl pause|resume`. Being a
/// plain file, it survives container restarts — pause is sticky by
/// construction, and works even when the harness isn't running.
#[must_use]
pub fn paused_marker() -> PathBuf {
    harness_dir().join(PAUSED_MARKER_FILE)
}