//! Lumbridge Compute — safe AI workload orchestration for accelerator nodes.

mod agent;
mod config;
mod eval;
mod gateway;
mod governor;
mod http;
mod lifecycle;
mod mcp;
mod mem;
mod proc;

use anyhow::Result;
use clap::{Parser, Subcommand};
use std::path::{Path, PathBuf};
use std::time::Duration;

use config::{find_scene, load_scenes, Registry, Scene};
use proc::State;

#[derive(Parser)]
#[command(
    name = "lumbridge-compute",
    version,
    about = "Lumbridge Compute — safe AI workload orchestration for accelerator nodes."
)]
struct Cli {
    /// Root dir containing registry/ and scenes/ (default: $LUMBRIDGE_COMPUTE_ROOT, $KUDA_ROOT, or current dir)
    #[arg(long, global = true)]
    root: Option<PathBuf>,
    #[command(subcommand)]
    cmd: Cmd,
}

#[derive(Subcommand)]
enum Cmd {
    /// Governor status: memory, budget, running set, headroom
    Status,
    /// Manage the model registry
    Model {
        #[command(subcommand)]
        cmd: ModelCmd,
    },
    /// Manage scenes (bundles of models)
    Scene {
        #[command(subcommand)]
        cmd: SceneCmd,
    },
    /// Run reproducible capability and serving-performance evaluations
    Eval {
        #[command(subcommand)]
        cmd: EvalCmd,
    },
    /// Run the memory watchdog in the foreground (kills the newest model before OOM-wedge)
    Watchdog {
        /// Kill the newest model if MemAvailable dips below this many GB
        #[arg(long, default_value_t = governor::WATCHDOG_FLOOR_GB)]
        floor: f64,
    },
    /// Run the stable streaming gateway in the foreground
    Gateway {
        #[arg(long, default_value = "127.0.0.1:8011")]
        listen: String,
        #[arg(long, default_value = "127.0.0.1:8001")]
        upstream: String,
    },
    /// Serve the Governor as a read-only JSON API over HTTP
    ///
    /// A second transport over the same operations the MCP server exposes, for a web UI. It
    /// never mutates: no activation, no stop, no eval run.
    Api {
        /// Loopback by default. This API has no authentication unless --token is set, and it
        /// reveals which models this node runs, so widening the bind is an explicit act.
        #[arg(long, default_value = "127.0.0.1:8012")]
        listen: String,
        /// Browser origin permitted to read this API. Repeatable. Empty means no browser may
        /// read it; `*` is deliberately not supported, because any page you visit would then
        /// be able to fingerprint this machine.
        #[arg(long = "allow-origin")]
        allow_origin: Vec<String>,
        /// Require `Authorization: Bearer <token>` on every request.
        #[arg(long)]
        token: Option<String>,
    },
    /// Serve the Governor to AI agents as MCP tools over stdio
    Mcp {
        /// Let an agent perform a real Scene transition, not just plan one.
        /// Off by default: the agent writes its own tool arguments, so the only
        /// meaningful gate on a production switch is one the operator sets here.
        #[arg(long)]
        allow_activate: bool,
    },
    /// Run the resident supervisor: resume desired Scene, gateway, and memory floor
    Agent {
        #[arg(long, default_value = "127.0.0.1:8011")]
        listen: String,
        #[arg(long, default_value = "127.0.0.1:8001")]
        upstream: String,
        #[arg(long, default_value_t = governor::WATCHDOG_FLOOR_GB)]
        floor: f64,
    },
}

#[derive(Subcommand)]
enum ModelCmd {
    /// List registered models and their live state
    Ls,
}

#[derive(Subcommand)]
enum SceneCmd {
    /// List scenes with total footprint
    Ls,
    /// Show a scene: models, footprints, and the Governor's admission verdict
    Show { name: String },
    /// Activate a scene: stop what's not in it, admit + start what is
    Activate {
        name: String,
        /// Print the plan without changing anything
        #[arg(long)]
        dry_run: bool,
    },
    /// Adopt an already-running exact Scene and bind legacy PIDs to process identities
    Adopt { name: String },
    /// Resume the persisted desired Scene, falling back to the previous known-good Scene
    Resume,
    /// Stop all Lumbridge Compute-managed models
    Deactivate,
}

#[derive(Subcommand)]
enum EvalCmd {
    /// List available evaluation suites
    Ls,
    /// Run a suite against an OpenAI-compatible endpoint
    Run {
        suite: String,
        #[arg(long, default_value = "http://127.0.0.1:8001/v1")]
        base_url: String,
        #[arg(long, default_value = "brain")]
        model: String,
        /// Override the suite's repetitions per case
        #[arg(long)]
        repeat: Option<u32>,
    },
}

fn root_dir(cli: &Cli) -> PathBuf {
    cli.root
        .clone()
        .or_else(|| {
            std::env::var("LUMBRIDGE_COMPUTE_ROOT")
                .ok()
                .map(PathBuf::from)
        })
        .or_else(|| std::env::var("KUDA_ROOT").ok().map(PathBuf::from))
        .unwrap_or_else(|| PathBuf::from("."))
}

fn main() -> Result<()> {
    let cli = Cli::parse();
    let root = root_dir(&cli);
    match &cli.cmd {
        Cmd::Status => cmd_status(&root),
        Cmd::Model { cmd } => match cmd {
            ModelCmd::Ls => cmd_model_ls(&root),
        },
        Cmd::Scene { cmd } => match cmd {
            SceneCmd::Ls => cmd_scene_ls(&root),
            SceneCmd::Show { name } => cmd_scene_show(&root, name),
            SceneCmd::Activate { name, dry_run } => lifecycle::activate(&root, name, *dry_run),
            SceneCmd::Adopt { name } => lifecycle::adopt(&root, name),
            SceneCmd::Resume => lifecycle::resume(&root),
            SceneCmd::Deactivate => lifecycle::deactivate(&root),
        },
        Cmd::Eval { cmd } => match cmd {
            EvalCmd::Ls => eval::list(&root),
            EvalCmd::Run {
                suite,
                base_url,
                model,
                repeat,
            } => eval::run(&root, suite, base_url, model, *repeat),
        },
        Cmd::Watchdog { floor } => cmd_watchdog(&root, *floor),
        Cmd::Gateway { listen, upstream } => gateway::run(listen, upstream),
        Cmd::Api {
            listen,
            allow_origin,
            token,
        } => http::run(
            listen,
            http::Config {
                root: root.clone(),
                allowed_origins: allow_origin.clone(),
                token: token.clone(),
            },
        ),
        Cmd::Mcp { allow_activate } => mcp::run(&root, *allow_activate),
        Cmd::Agent {
            listen,
            upstream,
            floor,
        } => agent::run(&root, listen, upstream, *floor),
    }
}

fn cmd_status(root: &Path) -> Result<()> {
    let reg = Registry::load(root)?;
    let m = mem::read()?;
    let committed = governor::committed_gb(&reg);
    let running = governor::running_ids(&reg);
    let budget = governor::DEFAULT_BUDGET_GB;
    // The binding constraint, not the generous one: admission enforces the declared
    // budget AND observed memory, so reporting only the declared headroom would promise
    // room the next `scene activate` is going to refuse.
    let headroom = governor::headroom_gb(committed, budget, Some(m.available_gb)).max(0.0);
    let declared_headroom = (budget - committed - governor::SAFETY_MARGIN_GB).max(0.0);
    let managed = State::load_checked(root)?;

    println!("Lumbridge Compute · governor");
    println!(
        "  memory     {:.1} GB total · {:.1} GB available",
        m.total_gb, m.available_gb
    );
    println!(
        "  budget     {:.0} GB  (safety margin {:.0} · watchdog floor {:.0})",
        budget,
        governor::SAFETY_MARGIN_GB,
        governor::WATCHDOG_FLOOR_GB
    );
    println!(
        "  committed  {committed:.1} GB across {} model(s)",
        running.len()
    );
    if headroom < declared_headroom {
        println!(
            "  headroom   {headroom:.1} GB admittable  (budget allows {declared_headroom:.1}; \
             MemAvailable is the tighter limit)"
        );
    } else {
        println!("  headroom   {headroom:.1} GB admittable");
    }
    println!();
    println!(
        "  scene      active={} desired={} fallback={}",
        managed.active_scene.as_deref().unwrap_or("-"),
        managed.desired_scene.as_deref().unwrap_or("-"),
        managed.last_known_good_scene.as_deref().unwrap_or("-")
    );
    if let Some(error) = &managed.last_error {
        println!("  last error {error}");
    }

    if running.is_empty() {
        println!("  (no registered models currently serving)");
    } else {
        println!("  running:");
        for id in &running {
            let mdl = &reg.models[id];
            let tag = if managed
                .procs
                .get(id)
                .is_some_and(|process| process.owned_alive())
            {
                "compute"
            } else {
                "ext "
            };
            println!(
                "    ● [{tag}] {:<12} {:>5.0} GB  :{:<5} {}",
                id,
                mdl.footprint_gb,
                port_str(mdl.serve.port),
                mdl.name
            );
        }
    }
    Ok(())
}

fn cmd_model_ls(root: &Path) -> Result<()> {
    let reg = Registry::load(root)?;
    println!(
        "{:<12} {:>6}  {:<6} {:<6} MODEL",
        "ID", "GB", "STATE", "PORT"
    );
    for (id, m) in &reg.models {
        println!(
            "{:<12} {:>6.0}  {:<6} {:<6} {}",
            id,
            m.footprint_gb,
            if governor::is_running(m) {
                "up"
            } else {
                "down"
            },
            port_str(m.serve.port),
            m.name
        );
    }
    Ok(())
}

fn cmd_scene_ls(root: &Path) -> Result<()> {
    let reg = Registry::load(root)?;
    let scenes = load_scenes(root)?;
    if scenes.is_empty() {
        println!("no scenes in {}/scenes", root.display());
        return Ok(());
    }
    println!("{:<12} {:>6}  {:<30} MODELS", "SCENE", "GB", "DESCRIPTION");
    for s in &scenes {
        let total = scene_footprint(s, &reg);
        println!(
            "{:<12} {:>6.0}  {:<30} {}",
            s.metadata.name,
            total,
            truncate(&s.metadata.description, 30),
            s.models.join(", ")
        );
    }
    Ok(())
}

fn cmd_scene_show(root: &Path, name: &str) -> Result<()> {
    let reg = Registry::load(root)?;
    let scene = find_scene(root, name)?;
    let budget = scene.budget_gb.unwrap_or(governor::DEFAULT_BUDGET_GB);

    println!(
        "scene {} (v{})",
        scene.metadata.name, scene.metadata.version
    );
    if !scene.metadata.description.is_empty() {
        println!("  {}", scene.metadata.description);
    }
    println!("  budget {budget:.0} GB\n  models:");

    let mut total = 0.0;
    let mut missing = Vec::new();
    for id in &scene.models {
        match reg.models.get(id) {
            Some(m) => {
                total += m.footprint_gb;
                let state = if governor::is_running(m) {
                    "up"
                } else {
                    "down"
                };
                println!(
                    "    {:<12} {:>5.0} GB  [{:<4}] {}",
                    id, m.footprint_gb, state, m.name
                );
            }
            None => {
                missing.push(id.clone());
                println!("    {id:<12}     ?     [MISSING from registry]");
            }
        }
    }

    let needed = total + governor::SAFETY_MARGIN_GB;
    println!(
        "\n  total footprint  {total:.1} GB  (+{:.0} safety = {needed:.1} GB)",
        governor::SAFETY_MARGIN_GB
    );
    let verdict = if !missing.is_empty() {
        format!("✗ {} model(s) missing from registry", missing.len())
    } else if needed <= budget {
        format!("✓ fits — {:.1} GB to spare", budget - needed)
    } else {
        format!("✗ exceeds budget by {:.1} GB", needed - budget)
    };
    println!("  admission        {verdict}");
    Ok(())
}

fn cmd_watchdog(root: &Path, floor: f64) -> Result<()> {
    println!(
        "Lumbridge Compute watchdog — killing the newest model if MemAvailable < {floor:.1} GB. Ctrl-C to stop."
    );
    loop {
        let m = mem::read()?;
        if m.available_gb < floor {
            let mut state = State::load_checked(root)?;
            match state.newest_alive() {
                Some((id, p)) => {
                    eprintln!(
                        "watchdog: MemAvailable {:.1} GB < floor {:.1} — killing newest '{id}' (pid {})",
                        m.available_gb, floor, p.pid
                    );
                    proc::stop_owned(&p)?;
                    state.procs.remove(&id);
                    state.save(root)?;
                }
                None => eprintln!(
                    "watchdog: MemAvailable {:.1} GB < floor {:.1} but no Lumbridge Compute-managed model to kill!",
                    m.available_gb, floor
                ),
            }
        }
        std::thread::sleep(Duration::from_secs(1));
    }
}

// ---- helpers ---------------------------------------------------------------

fn scene_footprint(s: &Scene, reg: &Registry) -> f64 {
    s.models
        .iter()
        .filter_map(|id| reg.models.get(id))
        .map(|m| m.footprint_gb)
        .sum()
}

fn port_str(p: Option<u16>) -> String {
    p.map(|p| p.to_string()).unwrap_or_else(|| "-".to_string())
}

fn truncate(s: &str, n: usize) -> String {
    if s.chars().count() <= n {
        s.to_string()
    } else {
        format!(
            "{}…",
            s.chars().take(n.saturating_sub(1)).collect::<String>()
        )
    }
}