use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex};
use std::time::Duration;

use anyhow::{Result, bail};
use clap::{Parser, Subcommand};
use hive_ag3nt::events::{Bus, LiveEvent};
use hive_ag3nt::login::{self, LoginState};
use hive_ag3nt::{DEFAULT_SOCKET, DEFAULT_WEB_PORT, client, mcp, turn, web_ui};
use hive_sh4re::{AgentRequest, AgentResponse};

#[derive(Parser)]
#[command(name = "hive-ag3nt", about = "hyperhive sub-agent harness")]
struct Cli {
    /// Path to the per-agent MCP socket (bind-mounted from the host).
    #[arg(long, global = true, default_value = DEFAULT_SOCKET)]
    socket: PathBuf,

    #[command(subcommand)]
    cmd: Cmd,
}

#[derive(Subcommand)]
enum Cmd {
    /// Run the long-lived harness loop. Polls inbox; replies via `claude --print`
    /// when available, falling back to a simple echo otherwise.
    Serve {
        /// Inbox poll interval in milliseconds.
        #[arg(long, default_value_t = 1000)]
        poll_ms: u64,
    },
    /// Send a message to another agent.
    Send { to: String, body: String },
    /// Pop one message from the inbox.
    Recv,
    /// Run the agent's MCP server on stdio. Spawned by `claude` via
    /// `--mcp-config`; tools dispatch through `/run/hive/mcp.sock` back into
    /// the hyperhive broker.
    Mcp,
}

#[tokio::main]
async fn main() -> Result<()> {
    tracing_subscriber::fmt()
        .with_env_filter(
            tracing_subscriber::EnvFilter::try_from_default_env()
                .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new("info")),
        )
        .init();

    let cli = Cli::parse();
    match cli.cmd {
        Cmd::Serve { poll_ms } => {
            let port = std::env::var("HIVE_PORT")
                .ok()
                .and_then(|s| s.parse::<u16>().ok())
                .unwrap_or(DEFAULT_WEB_PORT);
            let label = std::env::var("HIVE_LABEL").unwrap_or_else(|_| "hive-ag3nt".into());
            let claude_dir = PathBuf::from(login::DEFAULT_CLAUDE_DIR);
            let initial = LoginState::from_dir(&claude_dir);
            tracing::info!(state = ?initial, claude_dir = %claude_dir.display(), "harness boot");
            let login_state = Arc::new(Mutex::new(initial));
            let ui_state = login_state.clone();
            let bus = Bus::new();
            let ui_bus = bus.clone();
            let ui_socket = cli.socket.clone();
            tokio::spawn(async move {
                if let Err(e) = web_ui::serve(
                    label,
                    port,
                    ui_state,
                    ui_bus,
                    ui_socket,
                    web_ui::Flavor::Agent,
                )
                .await
                {
                    tracing::error!(error = ?e, "web ui failed");
                }
            });
            match initial {
                LoginState::Online => {
                    serve(
                        &cli.socket,
                        Duration::from_millis(poll_ms),
                        login_state,
                        bus,
                    )
                    .await
                }
                LoginState::NeedsLogin => {
                    // Partial-run mode: keep the harness alive (so the web UI
                    // stays bound) but don't drive the turn loop. Poll the
                    // claude dir; once a session lands we enter `serve`.
                    turn::wait_for_login(&claude_dir, login_state.clone(), poll_ms).await;
                    serve(
                        &cli.socket,
                        Duration::from_millis(poll_ms),
                        login_state,
                        bus,
                    )
                    .await
                }
            }
        }
        Cmd::Send { to, body } => {
            let resp: AgentResponse =
                client::request(&cli.socket, &AgentRequest::Send { to, body }).await?;
            render(&resp)?;
            check(&resp)
        }
        Cmd::Recv => {
            let resp: AgentResponse = client::request(&cli.socket, &AgentRequest::Recv).await?;
            render(&resp)?;
            check(&resp)
        }
        Cmd::Mcp => mcp::serve_agent_stdio(cli.socket).await,
    }
}

async fn serve(
    socket: &Path,
    interval: Duration,
    state: Arc<Mutex<LoginState>>,
    bus: Bus,
) -> Result<()> {
    tracing::info!(socket = %socket.display(), "hive-ag3nt serve");
    let _ = state; // reserved for future state transitions (turn-loop -> needs-login)
    let mcp_config = turn::write_mcp_config(socket).await?;
    let settings = turn::write_settings(socket).await?;
    let label = std::env::var("HIVE_LABEL").unwrap_or_else(|_| "hive-ag3nt".into());
    let system_prompt = turn::write_system_prompt(socket, &label, mcp::Flavor::Agent).await?;
    loop {
        let recv: Result<AgentResponse> = client::request(socket, &AgentRequest::Recv).await;
        match recv {
            Ok(AgentResponse::Message { from, body }) => {
                tracing::info!(%from, %body, "inbox");
                bus.emit(LiveEvent::TurnStart {
                    from: from.clone(),
                    body: body.clone(),
                });
                let prompt = format_wake_prompt(&from, &body);
                let outcome = turn::drive_turn(
                    &prompt,
                    &mcp_config,
                    &system_prompt,
                    &settings,
                    &bus,
                    mcp::Flavor::Agent,
                )
                .await;
                turn::emit_turn_end(&bus, &outcome);
            }
            Ok(AgentResponse::Empty) => {}
            Ok(AgentResponse::Ok | AgentResponse::Status { .. }) => {
                tracing::warn!("recv produced unexpected response kind");
            }
            Ok(AgentResponse::Err { message }) => {
                tracing::warn!(%message, "recv error");
            }
            Err(e) => {
                tracing::warn!(error = ?e, "recv failed; retrying");
            }
        }
        tokio::time::sleep(interval).await;
    }
}

/// Per-turn user prompt. The role/tools/etc. is in the system prompt
/// (`prompts/agent.md` → `claude --system-prompt-file`); this is just the
/// wake signal claude reacts to.
fn format_wake_prompt(from: &str, body: &str) -> String {
    format!("Incoming message from `{from}`:\n---\n{body}\n---")
}

fn render(resp: &AgentResponse) -> Result<()> {
    println!("{}", serde_json::to_string_pretty(resp)?);
    Ok(())
}

fn check(resp: &AgentResponse) -> Result<()> {
    if let AgentResponse::Err { message } = resp {
        bail!("{message}");
    }
    Ok(())
}