//! Runtime state + config shared between the host admin socket, the manager
//! socket, and the per-agent sockets: the broker, configured `agent_flake`,
//! and the map of registered agent sockets.

use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex};

use anyhow::{Context, Result};

use crate::agent_server::{self, AgentSocket};
use crate::approvals::Approvals;
use crate::broker::Broker;

const AGENT_RUNTIME_ROOT: &str = "/run/hyperhive/agents";
const MANAGER_RUNTIME_ROOT: &str = "/run/hyperhive/manager";
/// Manager-editable per-agent config repos. Bind-mounted RW into the manager
/// container as `/agents/<name>/`. Hive-c0re only writes to these on first
/// spawn (initial commit); after that it's manager-only.
const AGENT_STATE_ROOT: &str = "/var/lib/hyperhive/agents";
/// Hive-c0re-only authoritative per-agent config repos. Containers build from
/// these. Manager has no filesystem access; the only way to update is via
/// `request_apply_commit` + user approval.
const APPLIED_STATE_ROOT: &str = "/var/lib/hyperhive/applied";

pub struct Coordinator {
    pub broker: Arc<Broker>,
    pub approvals: Arc<Approvals>,
    /// URL of the hyperhive flake (no fragment). Inlined into per-agent
    /// `flake.nix` files as `inputs.hyperhive.url`.
    pub hyperhive_flake: String,
    agents: Mutex<HashMap<String, AgentSocket>>,
}

impl Coordinator {
    pub fn open(db_path: &Path, hyperhive_flake: String) -> Result<Self> {
        let broker = Broker::open(db_path).context("open broker")?;
        let approvals = Approvals::open(db_path).context("open approvals")?;
        Ok(Self {
            broker: Arc::new(broker),
            approvals: Arc::new(approvals),
            hyperhive_flake,
            agents: Mutex::new(HashMap::new()),
        })
    }

    pub fn register_agent(&self, name: &str) -> Result<PathBuf> {
        // Idempotent: drop any existing listener so re-registration (e.g. on rebuild,
        // or after a hive-c0re restart cleared /run/hyperhive) gets a fresh socket.
        self.unregister_agent(name);
        let agent_dir = Self::agent_dir(name);
        std::fs::create_dir_all(&agent_dir)
            .with_context(|| format!("create agent dir {}", agent_dir.display()))?;
        let socket_path = Self::socket_path(name);
        let socket = agent_server::start(name, &socket_path, self.broker.clone())?;
        self.agents.lock().unwrap().insert(name.to_owned(), socket);
        Ok(agent_dir)
    }

    pub fn unregister_agent(&self, name: &str) {
        if let Some(socket) = self.agents.lock().unwrap().remove(name) {
            socket.handle.abort();
            let _ = std::fs::remove_file(&socket.path);
        }
    }

    pub fn agent_dir(name: &str) -> PathBuf {
        PathBuf::from(format!("{AGENT_RUNTIME_ROOT}/{name}"))
    }

    pub fn socket_path(name: &str) -> PathBuf {
        Self::agent_dir(name).join("mcp.sock")
    }

    pub fn manager_dir() -> PathBuf {
        PathBuf::from(MANAGER_RUNTIME_ROOT)
    }

    pub fn manager_socket_path() -> PathBuf {
        Self::manager_dir().join("mcp.sock")
    }

    /// Manager-editable proposed config repo. Bind-mounted into the manager
    /// container as `/agents/<name>/config/`.
    pub fn agent_proposed_dir(name: &str) -> PathBuf {
        PathBuf::from(format!("{AGENT_STATE_ROOT}/{name}/config"))
    }

    /// Authoritative applied config repo. Hive-c0re-only.
    pub fn agent_applied_dir(name: &str) -> PathBuf {
        PathBuf::from(format!("{APPLIED_STATE_ROOT}/{name}"))
    }
}