use std::sync::Arc;
// tools/channels.rs — Channel tools (list, recv, send, notifications)
//
// Shared by consciousness agent and the MCP server.
// One-shot capnp RPC calls to channel daemon sockets.

use anyhow::{Context, Result};
use serde::Deserialize;

use super::Tool;

// ── Tool registry ──────────────────────────────────────────────

pub fn tools() -> [Tool; 6] {
    [
        Tool { name: "channel_list",
               description: "List all available channels and their status (connected, unread count).",
               parameters_json: r#"{"type":"object","properties":{}}"#,
               handler: Arc::new(|_a, _v| Box::pin(async { channel_list().await })) },
        Tool { name: "channel_recv",
               description: "Read messages from a channel.",
               parameters_json: r#"{"type":"object","properties":{"channel":{"type":"string","description":"Channel path (e.g. irc.#bcachefs, telegram.kent)"},"all_new":{"type":"boolean","description":"If true, return all unconsumed messages","default":true},"min_count":{"type":"integer","description":"Minimum number of lines to return","default":20}},"required":["channel"]}"#,
               handler: Arc::new(|_a, v| Box::pin(async move { channel_recv(&v).await })) },
        Tool { name: "channel_send",
               description: "Send a message to a channel.",
               parameters_json: r#"{"type":"object","properties":{"channel":{"type":"string","description":"Channel path (e.g. irc.#bcachefs, irc.pm.nick, telegram.kent)"},"message":{"type":"string","description":"Message to send"}},"required":["channel","message"]}"#,
               handler: Arc::new(|_a, v| Box::pin(async move { channel_send(&v).await })) },
        Tool { name: "channel_notifications",
               description: "Get pending channel notifications (unread signals). Does not consume messages — use channel_recv for that.",
               parameters_json: r#"{"type":"object","properties":{}}"#,
               handler: Arc::new(|_a, _v| Box::pin(async { channel_notifications().await })) },
        Tool { name: "channel_open",
               description: "Open a channel — start monitoring. For tmux: finds the pane by name and attaches pipe-pane.",
               parameters_json: r#"{"type":"object","properties":{"label":{"type":"string","description":"Channel label / tmux pane name"}},"required":["label"]}"#,
               handler: Arc::new(|_a, v| Box::pin(async move { channel_open(&v).await })) },
        Tool { name: "channel_close",
               description: "Close a channel — stop monitoring and clean up.",
               parameters_json: r#"{"type":"object","properties":{"channel":{"type":"string","description":"Channel path (e.g. tmux.ktest)"}},"required":["channel"]}"#,
               handler: Arc::new(|_a, v| Box::pin(async move { channel_close(&v).await })) },
    ]
}

// ── Tool implementations ───────────────────────────────────────

async fn channel_list() -> Result<String> {
    let result = fetch_all_channels().await;
    if result.is_empty() {
        return Ok("No channels configured.".into());
    }
    Ok(result.iter().map(|(name, connected, unread)| {
        let status = if *connected { "connected" } else { "disconnected" };
        let unread_str = if *unread > 0 { format!(" ({} unread)", unread) } else { String::new() };
        format!("{} — {}{}", name, status, unread_str)
    }).collect::<Vec<_>>().join("\n"))
}

#[derive(Deserialize)]
struct RecvArgs {
    channel: String,
    #[serde(default = "default_true")]
    all_new: bool,
    #[serde(default = "default_min_count")]
    min_count: u32,
}
fn default_true() -> bool { true }
fn default_min_count() -> u32 { 20 }

async fn channel_recv(args: &serde_json::Value) -> Result<String> {
    let a: RecvArgs = serde_json::from_value(args.clone())
        .context("invalid channel_recv arguments")?;
    let (sock, _) = find_daemon(&a.channel)?;
    let channel = a.channel;
    let all_new = a.all_new;
    let min_count = a.min_count;
    // capnp-rpc needs LocalSet — bridge to it via spawn_blocking
    tokio::task::spawn_blocking(move || {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all().build().unwrap();
        let local = tokio::task::LocalSet::new();
        local.block_on(&rt, rpc_recv(&sock, &channel, all_new, min_count))
    }).await?
        .map_err(|e| anyhow::anyhow!("{}", e))
}

#[derive(Deserialize)]
struct SendArgs {
    channel: String,
    message: String,
}

async fn channel_send(args: &serde_json::Value) -> Result<String> {
    let a: SendArgs = serde_json::from_value(args.clone())
        .context("invalid channel_send arguments")?;
    let (sock, _) = find_daemon(&a.channel)?;
    let channel = a.channel;
    let message = a.message;
    tokio::task::spawn_blocking(move || {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all().build().unwrap();
        let local = tokio::task::LocalSet::new();
        local.block_on(&rt, rpc_send(&sock, &channel, &message))
    }).await?
        .map_err(|e| anyhow::anyhow!("{}", e))
}

async fn channel_notifications() -> Result<String> {
    let result = fetch_all_channels().await;
    let unread: Vec<_> = result.iter().filter(|(_, _, u)| *u > 0).collect();
    if unread.is_empty() {
        Ok("No pending notifications.".into())
    } else {
        Ok(unread.iter()
            .map(|(name, _, count)| format!("{}: {} unread", name, count))
            .collect::<Vec<_>>()
            .join("\n"))
    }
}

async fn channel_open(args: &serde_json::Value) -> Result<String> {
    let label = args.get("label").and_then(|v| v.as_str())
        .context("label is required")?
        .to_string();
    let (sock, sublabel) = find_daemon(&label)?;
    tokio::task::spawn_blocking(move || {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all().build().unwrap();
        let local = tokio::task::LocalSet::new();
        local.block_on(&rt, rpc_open(&sock, &sublabel))
    }).await?
        .map_err(|e| anyhow::anyhow!("{}", e))
}

async fn channel_close(args: &serde_json::Value) -> Result<String> {
    let channel = args.get("channel").and_then(|v| v.as_str())
        .context("channel is required")?
        .to_string();
    let (sock, _) = find_daemon(&channel)?;
    tokio::task::spawn_blocking(move || {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all().build().unwrap();
        let local = tokio::task::LocalSet::new();
        local.block_on(&rt, rpc_close(&sock, &channel))
    }).await?
        .map_err(|e| anyhow::anyhow!("{}", e))
}

// ── Daemon resolution ─────────────────────────────────────────

fn channels_dir() -> std::path::PathBuf {
    dirs::home_dir()
        .unwrap_or_default()
        .join(".consciousness/channels")
}

/// Resolve a channel path to a daemon socket.
///
/// Walks the dot-delimited path from most-specific to least,
/// looking for a daemon socket at each level:
///   "tmux.ktest"           → finds tmux.sock, returns ("tmux.sock", "ktest")
///   "irc.libera.#bcachefs" → finds irc.sock, returns ("irc.sock", "libera.#bcachefs")
///
/// If no daemon is running, tries to start one via the supervisor.
fn find_daemon(path: &str) -> Result<(std::path::PathBuf, String)> {
    let dir = channels_dir();

    // Returns the sub-path after the matched prefix
    let rest_after = |prefix: &str| -> String {
        if prefix.len() < path.len() {
            path[prefix.len() + 1..].to_string()
        } else {
            String::new()
        }
    };

    // Walk from most-specific to least, looking for a socket
    let mut prefix = path;
    loop {
        let sock = dir.join(format!("{}.sock", prefix));
        if sock.exists() {
            return Ok((sock, rest_after(prefix)));
        }
        match prefix.rfind('.') {
            Some(pos) => prefix = &prefix[..pos],
            None => break,
        }
    }

    // No running daemon found — register and start via supervisor
    let top = path.split('.').next().unwrap_or(path);
    let mut sup = crate::thalamus::supervisor::Supervisor::new();
    sup.load_config();

    if !sup.has_daemon(top) {
        sup.add_daemon(top, crate::thalamus::supervisor::ChannelEntry {
            binary: format!("consciousness-channel-{}", top),
            enabled: true,
            autostart: true,
        });
    }

    sup.ensure_running();

    // Wait for socket (up to 3 seconds)
    let sock = dir.join(format!("{}.sock", top));
    for _ in 0..30 {
        if sock.exists() {
            return Ok((sock, rest_after(top)));
        }
        std::thread::sleep(std::time::Duration::from_millis(100));
    }

    anyhow::bail!("no daemon for channel path: {}", path)
}

// ── Channel RPC ────────────────────────────────────────────────

use capnp_rpc::{rpc_twoparty_capnp, twoparty, RpcSystem};
use futures::AsyncReadExt;
use tokio_util::compat::TokioAsyncReadCompatExt;
use crate::channel_capnp::channel_server;

async fn rpc_connect(sock: &std::path::Path) -> Result<channel_server::Client, String> {
    let stream = tokio::net::UnixStream::connect(sock).await
        .map_err(|e| format!("connect failed: {e}"))?;
    let (reader, writer) = stream.compat().split();
    let rpc_network = Box::new(twoparty::VatNetwork::new(
        futures::io::BufReader::new(reader),
        futures::io::BufWriter::new(writer),
        rpc_twoparty_capnp::Side::Client,
        Default::default(),
    ));
    let mut rpc_system = RpcSystem::new(rpc_network, None);
    let client: channel_server::Client =
        rpc_system.bootstrap(rpc_twoparty_capnp::Side::Server);
    tokio::task::spawn_local(rpc_system);
    Ok(client)
}

async fn rpc_recv(
    sock: &std::path::Path, channel: &str, all_new: bool, min_count: u32,
) -> Result<String, String> {
    let client = rpc_connect(sock).await?;
    let mut req = client.recv_request();
    req.get().set_channel(channel);
    req.get().set_all_new(all_new);
    req.get().set_min_count(min_count);
    let reply = req.send().promise.await.map_err(|e| format!("recv failed: {e}"))?;
    let text = reply.get().map_err(|e| format!("{e}"))?
        .get_text().map_err(|e| format!("{e}"))?
        .to_str().map_err(|e| format!("{e}"))?;
    if text.is_empty() { Ok("(no messages)".into()) } else { Ok(text.to_string()) }
}

async fn rpc_send(
    sock: &std::path::Path, channel: &str, message: &str,
) -> Result<String, String> {
    let client = rpc_connect(sock).await?;
    let mut req = client.send_request();
    req.get().set_channel(channel);
    req.get().set_message(message);
    req.send().promise.await.map_err(|e| format!("send failed: {e}"))?;
    Ok(format!("sent to {}", channel))
}

async fn rpc_list(sock: &std::path::Path) -> Option<Vec<(String, bool, u32)>> {
    let client = rpc_connect(sock).await.ok()?;
    let mut result = Vec::new();
    if let Ok(reply) = client.list_request().send().promise.await {
        if let Ok(r) = reply.get() {
            if let Ok(channels) = r.get_channels() {
                for ch in channels.iter() {
                    if let Ok(name) = ch.get_name() {
                        result.push((
                            name.to_str().unwrap_or("").to_string(),
                            ch.get_connected(),
                            ch.get_unread(),
                        ));
                    }
                }
            }
        }
    }
    Some(result)
}

async fn rpc_open(sock: &std::path::Path, label: &str) -> Result<String, String> {
    let client = rpc_connect(sock).await?;
    let mut req = client.open_request();
    req.get().set_label(label);
    req.send().promise.await.map_err(|e| format!("open failed: {e}"))?;
    Ok(format!("opened channel tmux.{}", label))
}

async fn rpc_close(sock: &std::path::Path, channel: &str) -> Result<String, String> {
    let client = rpc_connect(sock).await?;
    let mut req = client.close_request();
    req.get().set_channel(channel);
    req.send().promise.await.map_err(|e| format!("close failed: {e}"))?;
    Ok(format!("closed channel {}", channel))
}

// ── Fetch all channels ─────────────────────────────────────────

/// Fetch channel status from all daemon sockets.
/// Runs on a dedicated thread with LocalSet because capnp-rpc
/// uses Rc (not Send). This is the boundary between the
/// multi-thread runtime and the capnp world.
pub async fn fetch_all_channels() -> Vec<(String, bool, u32)> {
    tokio::task::spawn_blocking(|| {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all().build().unwrap();
        let local = tokio::task::LocalSet::new();
        local.block_on(&rt, fetch_all_channels_inner())
    })
    .await
    .unwrap_or_default()
}

async fn fetch_all_channels_inner() -> Vec<(String, bool, u32)> {
    let channels_dir = channels_dir();

    let mut sup = crate::thalamus::supervisor::Supervisor::new();
    sup.load_config();
    sup.ensure_running();

    let mut futs = Vec::new();
    for (daemon_name, _enabled, alive) in sup.status() {
        if !alive {
            futs.push(tokio::task::spawn_local({
                let name = daemon_name.clone();
                async move { vec![(name, false, 0u32)] }
            }));
            continue;
        }
        let sock = channels_dir.join(format!("{}.sock", daemon_name));
        futs.push(tokio::task::spawn_local({
            let name = daemon_name.clone();
            async move {
                match tokio::time::timeout(
                    std::time::Duration::from_secs(3),
                    rpc_list(&sock),
                ).await {
                    Ok(Some(channels)) if !channels.is_empty() => channels,
                    Ok(Some(_)) => vec![(name, true, 0)],
                    _ => vec![(name, false, 0)],
                }
            }
        }));
    }

    let mut result = Vec::new();
    for fut in futs {
        if let Ok(entries) = fut.await {
            result.extend(entries);
        }
    }
    result
}