use std::collections::{HashMap, HashSet};
use std::path::{Path, PathBuf};
use std::process::Stdio;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;

use anyhow::Result;
use chrono::{Local, NaiveDate, NaiveTime};
use serde::{Deserialize, Serialize};
use teloxide::dispatching::UpdateFilterExt;
use teloxide::net::Download;
use teloxide::prelude::*;
use teloxide::types::InputFile;
use tokio::io::AsyncBufReadExt;
use tokio::process::Command;
use tokio::sync::RwLock;
use tokio::time::Instant;
use tracing::{error, info, warn};
use base64::Engine;
use uuid::Uuid;

// ── config ──────────────────────────────────────────────────────────

#[derive(Deserialize)]
struct Config {
    #[serde(default = "default_name")]
    name: String,
    tg: TgConfig,
    auth: AuthConfig,
    session: SessionConfig,
    #[serde(default)]
    backend: BackendConfig,
    #[serde(default)]
    whisper_url: Option<String>,
}

fn default_name() -> String {
    "noc".to_string()
}

#[derive(Deserialize, Clone, Default)]
#[serde(tag = "type")]
enum BackendConfig {
    #[serde(rename = "claude")]
    #[default]
    Claude,
    #[serde(rename = "openai")]
    OpenAI {
        endpoint: String,
        model: String,
        #[serde(default = "default_api_key")]
        api_key: String,
    },
}

fn default_api_key() -> String {
    "unused".to_string()
}


#[derive(Deserialize)]
struct TgConfig {
    key: String,
}

#[derive(Deserialize)]
struct AuthConfig {
    passphrase: String,
}

#[derive(Deserialize)]
struct SessionConfig {
    refresh_hour: u32,
}

// ── persistent state ────────────────────────────────────────────────

#[derive(Serialize, Deserialize, Default)]
struct Persistent {
    authed: HashMap<i64, NaiveDate>,
    known_sessions: HashSet<String>,
}

#[derive(Serialize, Deserialize, Clone, Default)]
struct ConversationState {
    summary: String,
    messages: Vec<serde_json::Value>,
    total_messages: usize,
}

const MAX_WINDOW: usize = 100;
const SLIDE_SIZE: usize = 50;

// ── subagent & tool call ───────────────────────────────────────────

struct SubAgent {
    task: String,
    output: Arc<tokio::sync::RwLock<String>>,
    completed: Arc<AtomicBool>,
    exit_code: Arc<tokio::sync::RwLock<Option<i32>>>,
    pid: Option<u32>,
}

struct ToolCall {
    id: String,
    name: String,
    arguments: String,
}

fn tools_dir() -> PathBuf {
    // tools/ relative to the config file location
    let config_path = std::env::var("NOC_CONFIG").unwrap_or_else(|_| "config.yaml".into());
    let config_dir = Path::new(&config_path)
        .parent()
        .unwrap_or(Path::new("."));
    config_dir.join("tools")
}

/// Scan tools/ directory for scripts with --schema, merge with built-in tools.
/// Called on every API request so new/updated scripts take effect immediately.
fn discover_tools() -> serde_json::Value {
    let mut tools = vec![
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "spawn_agent",
                "description": "启动一个 Claude Code 子代理异步执行复杂任务。子代理可使用 shell、浏览器和搜索引擎，适合网页搜索、资料查找、技术调研、代码任务等。完成后会收到通知。",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "id": {"type": "string", "description": "简短唯一标识符（如 'research'、'fix-bug'）"},
                        "task": {"type": "string", "description": "给子代理的详细任务描述"}
                    },
                    "required": ["id", "task"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "agent_status",
                "description": "查看正在运行或已完成的子代理的状态和输出",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "id": {"type": "string", "description": "子代理标识符"}
                    },
                    "required": ["id"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "kill_agent",
                "description": "终止一个正在运行的子代理",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "id": {"type": "string", "description": "子代理标识符"}
                    },
                    "required": ["id"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "send_file",
                "description": "通过 Telegram 向用户发送服务器上的文件，文件必须存在于服务器文件系统中。",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "path": {"type": "string", "description": "服务器上文件的绝对路径"},
                        "caption": {"type": "string", "description": "可选的文件说明/描述"}
                    },
                    "required": ["path"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "update_scratch",
                "description": "更新你的草稿区（工作笔记、状态、提醒）。草稿区内容会附加到每条用户消息中，确保你始终可见。用于跨轮次跟踪上下文。",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "content": {"type": "string", "description": "完整的草稿区内容（替换之前的内容）"}
                    },
                    "required": ["content"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "update_memory",
                "description": "写入持久记忆槽。共 100 个槽位（0-99），跨会话保留。记忆槽内容会注入到每次对话的 system prompt 中。用于存储关键事实、用户偏好或重要上下文。内容设为空字符串可清除槽位。",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "slot_nr": {"type": "integer", "description": "槽位编号（0-99）"},
                        "content": {"type": "string", "description": "要存储的内容（最多200字符），空字符串表示清除该槽位"}
                    },
                    "required": ["slot_nr", "content"]
                }
            }
        }),
        serde_json::json!({
            "type": "function",
            "function": {
                "name": "gen_voice",
                "description": "将文字合成为语音并直接发送给用户。",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "text": {"type": "string", "description": "要合成语音的文字内容"}
                    },
                    "required": ["text"]
                }
            }
        }),
    ];

    // discover script tools
    let dir = tools_dir();
    if let Ok(entries) = std::fs::read_dir(&dir) {
        for entry in entries.flatten() {
            let path = entry.path();
            if !path.is_file() {
                continue;
            }
            // run --schema with a short timeout
            let output = std::process::Command::new(&path)
                .arg("--schema")
                .output();
            match output {
                Ok(out) if out.status.success() => {
                    let stdout = String::from_utf8_lossy(&out.stdout);
                    match serde_json::from_str::<serde_json::Value>(stdout.trim()) {
                        Ok(schema) => {
                            let name = schema["name"].as_str().unwrap_or("?");
                            info!(tool = %name, path = %path.display(), "discovered script tool");
                            tools.push(serde_json::json!({
                                "type": "function",
                                "function": schema,
                            }));
                        }
                        Err(e) => {
                            warn!(path = %path.display(), "invalid --schema JSON: {e}");
                        }
                    }
                }
                _ => {} // not a tool script, skip silently
            }
        }
    }

    serde_json::Value::Array(tools)
}

struct AppState {
    persist: RwLock<Persistent>,
    state_path: PathBuf,
    db: tokio::sync::Mutex<rusqlite::Connection>,
    agents: RwLock<HashMap<String, Arc<SubAgent>>>,
}

impl AppState {
    fn load(path: PathBuf) -> Self {
        let persist = std::fs::read_to_string(&path)
            .ok()
            .and_then(|s| serde_json::from_str(&s).ok())
            .unwrap_or_default();
        info!("loaded state from {}", path.display());

        let db_path = path.parent().unwrap_or(Path::new(".")).join("noc.db");
        let conn = rusqlite::Connection::open(&db_path)
            .unwrap_or_else(|e| panic!("open {}: {e}", db_path.display()));
        conn.execute_batch(
            "CREATE TABLE IF NOT EXISTS conversations (
                session_id TEXT PRIMARY KEY,
                summary TEXT NOT NULL DEFAULT '',
                total_messages INTEGER NOT NULL DEFAULT 0
            );
            CREATE TABLE IF NOT EXISTS messages (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                session_id TEXT NOT NULL,
                role TEXT NOT NULL,
                content TEXT NOT NULL,
                created_at TEXT NOT NULL DEFAULT (datetime('now', 'localtime'))
            );
            CREATE INDEX IF NOT EXISTS idx_messages_session ON messages(session_id);
            CREATE TABLE IF NOT EXISTS scratch_area (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                content TEXT NOT NULL,
                created_at TEXT NOT NULL DEFAULT (datetime('now'))
            );
            CREATE TABLE IF NOT EXISTS config (
                key TEXT PRIMARY KEY,
                value TEXT NOT NULL DEFAULT '',
                create_time TEXT NOT NULL DEFAULT (datetime('now')),
                update_time TEXT NOT NULL DEFAULT (datetime('now'))
            );
            CREATE TABLE IF NOT EXISTS config_history (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                key TEXT NOT NULL,
                value TEXT NOT NULL,
                create_time TEXT NOT NULL,
                update_time TEXT NOT NULL
            );
            CREATE TABLE IF NOT EXISTS memory_slots (
                slot_nr INTEGER PRIMARY KEY CHECK(slot_nr BETWEEN 0 AND 99),
                content TEXT NOT NULL DEFAULT ''
            );",
        )
        .expect("init db schema");

        // migrations
        let _ = conn.execute(
            "ALTER TABLE messages ADD COLUMN created_at TEXT NOT NULL DEFAULT ''",
            [],
        );

        info!("opened db {}", db_path.display());

        Self {
            persist: RwLock::new(persist),
            state_path: path,
            db: tokio::sync::Mutex::new(conn),
            agents: RwLock::new(HashMap::new()),
        }
    }

    async fn save(&self) {
        let data = self.persist.read().await;
        if let Ok(json) = serde_json::to_string_pretty(&*data) {
            if let Err(e) = std::fs::write(&self.state_path, json) {
                error!("save state: {e}");
            }
        }
    }

    async fn load_conv(&self, sid: &str) -> ConversationState {
        let db = self.db.lock().await;
        let (summary, total) = db
            .query_row(
                "SELECT summary, total_messages FROM conversations WHERE session_id = ?1",
                [sid],
                |row| Ok((row.get::<_, String>(0)?, row.get::<_, usize>(1)?)),
            )
            .unwrap_or_default();

        let mut stmt = db
            .prepare("SELECT role, content, created_at FROM messages WHERE session_id = ?1 ORDER BY id")
            .unwrap();
        let messages: Vec<serde_json::Value> = stmt
            .query_map([sid], |row| {
                let role: String = row.get(0)?;
                let content: String = row.get(1)?;
                let ts: String = row.get(2)?;
                let tagged = if ts.is_empty() {
                    content
                } else {
                    format!("[{ts}] {content}")
                };
                Ok(serde_json::json!({"role": role, "content": tagged}))
            })
            .unwrap()
            .filter_map(|r| r.ok())
            .collect();

        ConversationState {
            summary,
            messages,
            total_messages: total,
        }
    }

    async fn push_message(&self, sid: &str, role: &str, content: &str) {
        let db = self.db.lock().await;
        let _ = db.execute(
            "INSERT OR IGNORE INTO conversations (session_id) VALUES (?1)",
            [sid],
        );
        let _ = db.execute(
            "INSERT INTO messages (session_id, role, content, created_at) VALUES (?1, ?2, ?3, datetime('now', 'localtime'))",
            rusqlite::params![sid, role, content],
        );
    }

    async fn message_count(&self, sid: &str) -> usize {
        let db = self.db.lock().await;
        db.query_row(
            "SELECT COUNT(*) FROM messages WHERE session_id = ?1",
            [sid],
            |row| row.get(0),
        )
        .unwrap_or(0)
    }

    async fn slide_window(&self, sid: &str, new_summary: &str, slide_size: usize) {
        let db = self.db.lock().await;
        let _ = db.execute(
            "DELETE FROM messages WHERE id IN (
                SELECT id FROM messages WHERE session_id = ?1 ORDER BY id LIMIT ?2
            )",
            rusqlite::params![sid, slide_size],
        );
        let _ = db.execute(
            "UPDATE conversations SET summary = ?1, total_messages = total_messages + ?2 \
             WHERE session_id = ?3",
            rusqlite::params![new_summary, slide_size, sid],
        );
    }

    async fn get_oldest_messages(&self, sid: &str, count: usize) -> Vec<serde_json::Value> {
        let db = self.db.lock().await;
        let mut stmt = db
            .prepare(
                "SELECT role, content FROM messages WHERE session_id = ?1 ORDER BY id LIMIT ?2",
            )
            .unwrap();
        stmt.query_map(rusqlite::params![sid, count], |row| {
            let role: String = row.get(0)?;
            let content: String = row.get(1)?;
            Ok(serde_json::json!({"role": role, "content": content}))
        })
        .unwrap()
        .filter_map(|r| r.ok())
        .collect()
    }

    async fn get_scratch(&self) -> String {
        let db = self.db.lock().await;
        db.query_row(
            "SELECT content FROM scratch_area ORDER BY id DESC LIMIT 1",
            [],
            |row| row.get(0),
        )
        .unwrap_or_default()
    }

    async fn push_scratch(&self, content: &str) {
        let db = self.db.lock().await;
        let _ = db.execute(
            "INSERT INTO scratch_area (content) VALUES (?1)",
            [content],
        );
    }

    async fn get_config(&self, key: &str) -> Option<String> {
        let db = self.db.lock().await;
        db.query_row(
            "SELECT value FROM config WHERE key = ?1",
            [key],
            |row| row.get(0),
        )
        .ok()
    }

    async fn get_memory_slots(&self) -> Vec<(i32, String)> {
        let db = self.db.lock().await;
        let mut stmt = db
            .prepare("SELECT slot_nr, content FROM memory_slots WHERE content != '' ORDER BY slot_nr")
            .unwrap();
        stmt.query_map([], |row| Ok((row.get(0)?, row.get(1)?)))
            .unwrap()
            .filter_map(|r| r.ok())
            .collect()
    }

    async fn set_memory_slot(&self, slot_nr: i32, content: &str) -> Result<()> {
        if !(0..=99).contains(&slot_nr) {
            anyhow::bail!("slot_nr must be 0-99, got {slot_nr}");
        }
        if content.len() > 200 {
            anyhow::bail!("content too long: {} chars (max 200)", content.len());
        }
        let db = self.db.lock().await;
        db.execute(
            "INSERT INTO memory_slots (slot_nr, content) VALUES (?1, ?2) \
             ON CONFLICT(slot_nr) DO UPDATE SET content = ?2",
            rusqlite::params![slot_nr, content],
        )?;
        Ok(())
    }
}

// ── helpers ─────────────────────────────────────────────────────────

fn session_date(refresh_hour: u32) -> NaiveDate {
    let now = Local::now();
    let refresh = NaiveTime::from_hms_opt(refresh_hour, 0, 0).unwrap();
    if now.time() < refresh {
        now.date_naive() - chrono::Duration::days(1)
    } else {
        now.date_naive()
    }
}

fn session_uuid(prefix: &str, chat_id: i64, refresh_hour: u32) -> String {
    let date = session_date(refresh_hour);
    let name = format!("{}-{}-{}", prefix, chat_id, date.format("%Y%m%d"));
    Uuid::new_v5(&Uuid::NAMESPACE_OID, name.as_bytes()).to_string()
}

fn home_dir() -> PathBuf {
    PathBuf::from(std::env::var("HOME").unwrap_or_else(|_| "/tmp".into()))
}

fn incoming_dir() -> PathBuf {
    home_dir().join("incoming")
}

fn outgoing_dir(sid: &str) -> PathBuf {
    home_dir().join("outgoing").join(sid)
}

// ── main ────────────────────────────────────────────────────────────

#[tokio::main]
async fn main() {
    tracing_subscriber::fmt()
        .with_env_filter(
            tracing_subscriber::EnvFilter::from_default_env()
                .add_directive("noc=info".parse().unwrap()),
        )
        .init();

    let config_path = std::env::var("NOC_CONFIG").unwrap_or_else(|_| "config.yaml".into());
    let raw = std::fs::read_to_string(&config_path)
        .unwrap_or_else(|e| panic!("read {config_path}: {e}"));
    let config: Config =
        serde_yaml::from_str(&raw).unwrap_or_else(|e| panic!("parse config: {e}"));

    let state_path = std::env::var("NOC_STATE")
        .map(PathBuf::from)
        .unwrap_or_else(|_| PathBuf::from("state.json"));
    let state = Arc::new(AppState::load(state_path));

    let _ = std::fs::create_dir_all(incoming_dir());

    let bot = Bot::new(&config.tg.key);
    let me = bot.get_me().await.unwrap();
    let bot_username = Arc::new(me.username.clone().unwrap_or_default());
    info!(username = %bot_username, "noc bot starting");

    let handler = Update::filter_message().endpoint(handle);

    Dispatcher::builder(bot, handler)
        .dependencies(dptree::deps![state, Arc::new(config), bot_username])
        .default_handler(|_| async {})
        .build()
        .dispatch()
        .await;
}

// ── file download ───────────────────────────────────────────────────

async fn download_tg_file(bot: &Bot, file_id: &str, filename: &str) -> Result<PathBuf> {
    let dir = incoming_dir();
    tokio::fs::create_dir_all(&dir).await?;

    let dest = dir.join(filename);
    let tf = bot.get_file(file_id).await?;
    let mut file = tokio::fs::File::create(&dest).await?;
    bot.download_file(&tf.path, &mut file).await?;

    info!("downloaded {} -> {}", filename, dest.display());
    Ok(dest)
}

// ── outgoing scan ───────────────────────────────────────────────────

async fn snapshot_dir(dir: &Path) -> HashSet<PathBuf> {
    let mut set = HashSet::new();
    if let Ok(mut entries) = tokio::fs::read_dir(dir).await {
        while let Ok(Some(entry)) = entries.next_entry().await {
            let path = entry.path();
            if path.is_file() {
                set.insert(path);
            }
        }
    }
    set
}

async fn new_files_in(dir: &Path, before: &HashSet<PathBuf>) -> Vec<PathBuf> {
    let mut files = Vec::new();
    if let Ok(mut entries) = tokio::fs::read_dir(dir).await {
        while let Ok(Some(entry)) = entries.next_entry().await {
            let path = entry.path();
            if path.is_file() && !before.contains(&path) {
                files.push(path);
            }
        }
    }
    files.sort();
    files
}

// ── handler ─────────────────────────────────────────────────────────

async fn handle(
    bot: Bot,
    msg: Message,
    state: Arc<AppState>,
    config: Arc<Config>,
    _bot_username: Arc<String>,
) -> ResponseResult<()> {
    let chat_id = msg.chat.id;
    let is_private = msg.chat.is_private();
    let text = msg.text().or(msg.caption()).unwrap_or("").to_string();
    let raw_id = chat_id.0;
    let date = session_date(config.session.refresh_hour);

    let is_authed = {
        let p = state.persist.read().await;
        p.authed.get(&raw_id) == Some(&date)
    };

    if !is_authed {
        if text.trim() == config.auth.passphrase {
            {
                let mut p = state.persist.write().await;
                p.authed.insert(raw_id, date);
            }
            state.save().await;
            bot.send_message(chat_id, "authenticated").await?;
            info!(chat = raw_id, "authed");
        } else {
            bot.send_message(chat_id, "not authenticated").await?;
        }
        return Ok(());
    }

    if let Err(e) = handle_inner(&bot, &msg, chat_id, &text, is_private, &state, &config).await {
        error!(chat = raw_id, "handle: {e:#}");
        let _ = bot.send_message(chat_id, format!("[error] {e:#}")).await;
    }

    Ok(())
}

async fn handle_inner(
    bot: &Bot,
    msg: &Message,
    chat_id: ChatId,
    text: &str,
    is_private: bool,
    state: &Arc<AppState>,
    config: &Arc<Config>,
) -> Result<()> {
    let mut uploaded: Vec<PathBuf> = Vec::new();
    let mut download_errors: Vec<String> = Vec::new();
    let mut transcriptions: Vec<String> = Vec::new();

    if let Some(doc) = msg.document() {
        let name = doc.file_name.as_deref().unwrap_or("file");
        match download_tg_file(bot, &doc.file.id, name).await {
            Ok(p) => uploaded.push(p),
            Err(e) => download_errors.push(format!("{name}: {e:#}")),
        }
    }

    if let Some(photos) = msg.photo() {
        if let Some(photo) = photos.last() {
            let name = format!("photo_{}.jpg", Local::now().format("%H%M%S"));
            match download_tg_file(bot, &photo.file.id, &name).await {
                Ok(p) => uploaded.push(p),
                Err(e) => download_errors.push(format!("photo: {e:#}")),
            }
        }
    }

    if let Some(audio) = msg.audio() {
        let fallback = format!("audio_{}.ogg", Local::now().format("%H%M%S"));
        let name = audio.file_name.as_deref().unwrap_or(&fallback);
        match download_tg_file(bot, &audio.file.id, name).await {
            Ok(p) => {
                if let Some(url) = &config.whisper_url {
                    match transcribe_audio(url, &p).await {
                        Ok(t) if !t.is_empty() => transcriptions.push(t),
                        Ok(_) => uploaded.push(p),
                        Err(e) => {
                            warn!("transcribe failed: {e:#}");
                            uploaded.push(p);
                        }
                    }
                } else {
                    uploaded.push(p);
                }
            }
            Err(e) => download_errors.push(format!("audio: {e:#}")),
        }
    }

    if let Some(voice) = msg.voice() {
        let name = format!("voice_{}.ogg", Local::now().format("%H%M%S"));
        match download_tg_file(bot, &voice.file.id, &name).await {
            Ok(p) => {
                if let Some(url) = &config.whisper_url {
                    match transcribe_audio(url, &p).await {
                        Ok(t) if !t.is_empty() => transcriptions.push(t),
                        Ok(_) => uploaded.push(p),
                        Err(e) => {
                            warn!("transcribe failed: {e:#}");
                            uploaded.push(p);
                        }
                    }
                } else {
                    uploaded.push(p);
                }
            }
            Err(e) => download_errors.push(format!("voice: {e:#}")),
        }
    }

    if let Some(video) = msg.video() {
        let fallback = format!("video_{}.mp4", Local::now().format("%H%M%S"));
        let name = video.file_name.as_deref().unwrap_or(&fallback);
        match download_tg_file(bot, &video.file.id, name).await {
            Ok(p) => uploaded.push(p),
            Err(e) => download_errors.push(format!("video: {e:#}")),
        }
    }

    if let Some(vn) = msg.video_note() {
        let name = format!("videonote_{}.mp4", Local::now().format("%H%M%S"));
        match download_tg_file(bot, &vn.file.id, &name).await {
            Ok(p) => uploaded.push(p),
            Err(e) => download_errors.push(format!("video_note: {e:#}")),
        }
    }

    if text.is_empty() && uploaded.is_empty() && transcriptions.is_empty() {
        if !download_errors.is_empty() {
            let err_msg = format!("[文件下载失败]\n{}", download_errors.join("\n"));
            bot.send_message(chat_id, err_msg).await?;
        }
        return Ok(());
    }

    let sid = session_uuid(&config.name, chat_id.0, config.session.refresh_hour);
    info!(%sid, "recv");

    let out_dir = outgoing_dir(&sid);
    tokio::fs::create_dir_all(&out_dir).await?;
    let before = snapshot_dir(&out_dir).await;

    // handle diag command (OpenAI backend only)
    if text.trim() == "diag" {
        if let BackendConfig::OpenAI { .. } = &config.backend {
            let conv = state.load_conv(&sid).await;
            let count = state.message_count(&sid).await;
            let persona = state.get_config("persona").await.unwrap_or_default();
            let scratch = state.get_scratch().await;
            let tools = discover_tools();
            let empty = vec![];
            let tools_arr = tools.as_array().unwrap_or(&empty);

            let mut diag = format!(
                "# NOC Diag\n\n\
                 ## Session\n\
                 - id: `{sid}`\n\
                 - window: {count}/{MAX_WINDOW} (slide at {MAX_WINDOW}, drop {SLIDE_SIZE})\n\
                 - total processed: {}\n\n\
                 ## Persona ({} chars)\n```\n{}\n```\n\n\
                 ## Scratch ({} chars)\n```\n{}\n```\n\n\
                 ## Summary ({} chars)\n```\n{}\n```\n\n\
                 ## Tools ({} registered)\n",
                conv.total_messages + count,
                persona.len(),
                if persona.is_empty() { "(default)" } else { &persona },
                scratch.len(),
                if scratch.is_empty() { "(empty)" } else { &scratch },
                conv.summary.len(),
                if conv.summary.is_empty() {
                    "(empty)".to_string()
                } else {
                    conv.summary
                },
                tools_arr.len(),
            );
            for tool in tools_arr {
                let func = &tool["function"];
                let name = func["name"].as_str().unwrap_or("?");
                let desc = func["description"].as_str().unwrap_or("");
                let params = serde_json::to_string_pretty(&func["parameters"])
                    .unwrap_or_default();
                diag.push_str(&format!(
                    "### `{name}`\n{desc}\n\n```json\n{params}\n```\n\n"
                ));
            }

            let memory_slots = state.get_memory_slots().await;
            diag.push_str(&format!("## Memory Slots ({}/100 used)\n", memory_slots.len()));
            if memory_slots.is_empty() {
                diag.push_str("(empty)\n\n");
            } else {
                for (nr, content) in &memory_slots {
                    diag.push_str(&format!("- `[{nr}]` {content}\n"));
                }
                diag.push('\n');
            }

            let tmp = std::env::temp_dir().join(format!("noc-diag-{sid}.md"));
            tokio::fs::write(&tmp, &diag).await?;
            bot.send_document(chat_id, InputFile::file(&tmp))
                .await?;
            let _ = tokio::fs::remove_file(&tmp).await;
            return Ok(());
        }
    }

    // handle "cc" prefix: pass directly to claude -p, no session, no history
    if let Some(cc_prompt) = text.strip_prefix("cc").map(|s| s.trim_start()) {
        if !cc_prompt.is_empty() {
            info!(%sid, "cc passthrough");
            let prompt = build_prompt(cc_prompt, &uploaded, &download_errors, &transcriptions);
            match run_claude_streaming(&[], &prompt, bot, chat_id).await {
                Ok(_) => {}
                Err(e) => {
                    error!(%sid, "cc claude: {e:#}");
                    let _ = bot.send_message(chat_id, format!("[error] {e:#}")).await;
                }
            }
            return Ok(());
        }
    }

    let prompt = build_prompt(text, &uploaded, &download_errors, &transcriptions);

    match &config.backend {
        BackendConfig::Claude => {
            let known = state.persist.read().await.known_sessions.contains(&sid);
            let result =
                invoke_claude_streaming(&sid, &prompt, known, bot, chat_id).await;
            match &result {
                Ok(_) => {
                    if !known {
                        state.persist.write().await.known_sessions.insert(sid.clone());
                        state.save().await;
                    }
                }
                Err(e) => {
                    error!(%sid, "claude: {e:#}");
                    let _ = bot.send_message(chat_id, format!("[error] {e:#}")).await;
                }
            }
        }
        BackendConfig::OpenAI {
            endpoint,
            model,
            api_key,
        } => {
            let conv = state.load_conv(&sid).await;
            let persona = state.get_config("persona").await.unwrap_or_default();
            let memory_slots = state.get_memory_slots().await;
            let system_msg = build_system_prompt(&conv.summary, &persona, &memory_slots);

            let mut api_messages = vec![system_msg];
            api_messages.extend(conv.messages);

            let scratch = state.get_scratch().await;
            let user_content = build_user_content(&prompt, &scratch, &uploaded);
            api_messages.push(serde_json::json!({"role": "user", "content": user_content}));

            match run_openai_with_tools(
                endpoint, model, api_key, api_messages, bot, chat_id, state, &sid, config, is_private,
            )
            .await
            {
                Ok(response) => {
                    state.push_message(&sid, "user", &prompt).await;
                    if !response.is_empty() {
                        state.push_message(&sid, "assistant", &response).await;
                    }

                    // sliding window
                    let count = state.message_count(&sid).await;
                    if count >= MAX_WINDOW {
                        info!(%sid, "sliding window: {count} messages, summarizing oldest {SLIDE_SIZE}");
                        let _ = bot
                            .send_message(chat_id, "[整理记忆中...]")
                            .await;

                        let to_summarize =
                            state.get_oldest_messages(&sid, SLIDE_SIZE).await;
                        let current_summary = {
                            let db = state.db.lock().await;
                            db.query_row(
                                "SELECT summary FROM conversations WHERE session_id = ?1",
                                [&sid],
                                |row| row.get::<_, String>(0),
                            )
                            .unwrap_or_default()
                        };

                        match summarize_messages(
                            endpoint,
                            model,
                            api_key,
                            &current_summary,
                            &to_summarize,
                        )
                        .await
                        {
                            Ok(new_summary) => {
                                state.slide_window(&sid, &new_summary, SLIDE_SIZE).await;
                                let remaining = state.message_count(&sid).await;
                                info!(%sid, "window slid, {remaining} messages remain, summary {} chars", new_summary.len());
                            }
                            Err(e) => {
                                warn!(%sid, "summarize failed: {e:#}, keeping all messages");
                            }
                        }
                    }
                }
                Err(e) => {
                    error!(%sid, "openai: {e:#}");
                    let _ = bot.send_message(chat_id, format!("[error] {e:#}")).await;
                }
            }
        }
    }

    // send new files from outgoing dir
    let new_files = new_files_in(&out_dir, &before).await;
    for path in &new_files {
        info!(%sid, "sending file: {}", path.display());
        if let Err(e) = bot.send_document(chat_id, InputFile::file(path)).await {
            error!(%sid, "send_document {}: {e:#}", path.display());
            let _ = bot
                .send_message(chat_id, format!("[发送文件失败: {}]", path.display()))
                .await;
        }
    }

    Ok(())
}

fn build_prompt(
    text: &str,
    uploaded: &[PathBuf],
    errors: &[String],
    transcriptions: &[String],
) -> String {
    let mut parts = Vec::new();

    for t in transcriptions {
        parts.push(format!("[语音消息] {t}"));
    }

    for f in uploaded {
        parts.push(format!("[用户上传了文件: {}]", f.display()));
    }

    for e in errors {
        parts.push(format!("[文件下载失败: {e}]"));
    }

    if !text.is_empty() {
        parts.push(text.to_string());
    }

    parts.join("\n")
}

async fn transcribe_audio(whisper_url: &str, file_path: &Path) -> Result<String> {
    let client = reqwest::Client::new();
    let url = format!("{}/v1/audio/transcriptions", whisper_url.trim_end_matches('/'));
    let file_bytes = tokio::fs::read(file_path).await?;
    let file_name = file_path
        .file_name()
        .and_then(|n| n.to_str())
        .unwrap_or("audio.ogg")
        .to_string();
    let part = reqwest::multipart::Part::bytes(file_bytes)
        .file_name(file_name)
        .mime_str("audio/ogg")?;
    let form = reqwest::multipart::Form::new()
        .part("file", part)
        .text("model", "base");
    let resp = client.post(&url).multipart(form).send().await?.error_for_status()?;
    let json: serde_json::Value = resp.json().await?;
    Ok(json["text"].as_str().unwrap_or("").to_string())
}

fn build_system_prompt(summary: &str, persona: &str, memory_slots: &[(i32, String)]) -> serde_json::Value {
    let mut text = if persona.is_empty() {
        String::from("你是一个AI助手。")
    } else {
        persona.to_string()
    };

    text.push_str(
        "\n\n你可以使用提供的工具来完成任务。\
         当需要执行命令、运行代码或启动复杂子任务时，直接调用对应的工具，不要只是描述你会怎么做。\
         当需要搜索信息（如网页搜索、资料查找、技术调研等）时，使用 spawn_agent 启动一个子代理来完成搜索任务，\
         子代理可以使用浏览器和搜索引擎，搜索完成后你会收到结果通知。\
         输出格式：使用纯文本或基础Markdown（加粗、列表、代码块）。\
         不要使用LaTeX公式（$...$）、特殊Unicode符号（→←↔）或HTML标签，Telegram无法渲染这些。",
    );

    if !memory_slots.is_empty() {
        text.push_str("\n\n## 持久记忆（跨会话保留）\n");
        for (nr, content) in memory_slots {
            text.push_str(&format!("[{nr}] {content}\n"));
        }
    }

    if !summary.is_empty() {
        text.push_str("\n\n## 之前的对话总结\n");
        text.push_str(summary);
    }

    serde_json::json!({"role": "system", "content": text})
}

/// Build user message content, with optional images/videos as multimodal input.
fn build_user_content(
    text: &str,
    scratch: &str,
    media: &[PathBuf],
) -> serde_json::Value {
    let full_text = if scratch.is_empty() {
        text.to_string()
    } else {
        format!("{text}\n\n[scratch]\n{scratch}")
    };

    // collect media data (images + videos)
    let mut media_parts: Vec<serde_json::Value> = Vec::new();
    for path in media {
        let (mime, is_video) = match path
            .extension()
            .and_then(|e| e.to_str())
            .map(|e| e.to_lowercase())
            .as_deref()
        {
            Some("jpg" | "jpeg") => ("image/jpeg", false),
            Some("png") => ("image/png", false),
            Some("gif") => ("image/gif", false),
            Some("webp") => ("image/webp", false),
            Some("mp4") => ("video/mp4", true),
            Some("webm") => ("video/webm", true),
            Some("mov") => ("video/quicktime", true),
            _ => continue,
        };
        if let Ok(data) = std::fs::read(path) {
            let b64 = base64::engine::general_purpose::STANDARD.encode(&data);
            let data_url = format!("data:{mime};base64,{b64}");
            if is_video {
                media_parts.push(serde_json::json!({
                    "type": "video_url",
                    "video_url": {"url": data_url}
                }));
            } else {
                media_parts.push(serde_json::json!({
                    "type": "image_url",
                    "image_url": {"url": data_url}
                }));
            }
        }
    }

    if media_parts.is_empty() {
        // plain text — more compatible
        serde_json::Value::String(full_text)
    } else {
        // multimodal array
        let mut content = vec![serde_json::json!({"type": "text", "text": full_text})];
        content.extend(media_parts);
        serde_json::Value::Array(content)
    }
}

async fn summarize_messages(
    endpoint: &str,
    model: &str,
    api_key: &str,
    existing_summary: &str,
    dropped: &[serde_json::Value],
) -> Result<String> {
    let msgs_text: String = dropped
        .iter()
        .filter_map(|m| {
            let role = m["role"].as_str()?;
            let content = m["content"].as_str()?;
            Some(format!("{role}: {content}"))
        })
        .collect::<Vec<_>>()
        .join("\n\n");

    let prompt = if existing_summary.is_empty() {
        format!(
            "请将以下对话总结为约4000字符的摘要，保留关键信息和上下文：\n\n{}",
            msgs_text
        )
    } else {
        format!(
            "请将以下新对话内容整合到现有总结中，保持总结在约4000字符以内。\
             保留重要信息，让较旧的话题自然淡出。\n\n\
             现有总结：\n{}\n\n新对话：\n{}",
            existing_summary, msgs_text
        )
    };

    let client = reqwest::Client::new();
    let url = format!("{}/chat/completions", endpoint.trim_end_matches('/'));

    let body = serde_json::json!({
        "model": model,
        "messages": [
            {"role": "system", "content": "你是一个对话总结助手。请生成简洁但信息丰富的总结。"},
            {"role": "user", "content": prompt}
        ],
    });

    let resp = client
        .post(&url)
        .header("Authorization", format!("Bearer {api_key}"))
        .json(&body)
        .send()
        .await?
        .error_for_status()?;

    let json: serde_json::Value = resp.json().await?;
    let summary = json["choices"][0]["message"]["content"]
        .as_str()
        .unwrap_or("")
        .to_string();

    Ok(summary)
}

// ── tool execution ─────────────────────────────────────────────────

async fn execute_tool(
    name: &str,
    arguments: &str,
    state: &Arc<AppState>,
    bot: &Bot,
    chat_id: ChatId,
    sid: &str,
    config: &Arc<Config>,
) -> String {
    let args: serde_json::Value = match serde_json::from_str(arguments) {
        Ok(v) => v,
        Err(e) => return format!("Invalid arguments: {e}"),
    };

    match name {
        "spawn_agent" => {
            let id = args["id"].as_str().unwrap_or("agent");
            let task = args["task"].as_str().unwrap_or("");
            spawn_agent(id, task, state, bot, chat_id, sid, config).await
        }
        "agent_status" => {
            let id = args["id"].as_str().unwrap_or("");
            check_agent_status(id, state).await
        }
        "kill_agent" => {
            let id = args["id"].as_str().unwrap_or("");
            kill_agent(id, state).await
        }
        "send_file" => {
            let path_str = args["path"].as_str().unwrap_or("");
            let caption = args["caption"].as_str().unwrap_or("");
            let path = Path::new(path_str);
            if !path.exists() {
                return format!("File not found: {path_str}");
            }
            if !path.is_file() {
                return format!("Not a file: {path_str}");
            }
            let input_file = InputFile::file(path);
            let mut req = bot.send_document(chat_id, input_file);
            if !caption.is_empty() {
                req = req.caption(caption);
            }
            match req.await {
                Ok(_) => format!("File sent: {path_str}"),
                Err(e) => format!("Failed to send file: {e:#}"),
            }
        }
        "update_scratch" => {
            let content = args["content"].as_str().unwrap_or("");
            state.push_scratch(content).await;
            format!("Scratch updated ({} chars)", content.len())
        }
        "update_memory" => {
            let slot_nr = args["slot_nr"].as_i64().unwrap_or(-1) as i32;
            let content = args["content"].as_str().unwrap_or("");
            match state.set_memory_slot(slot_nr, content).await {
                Ok(_) => {
                    if content.is_empty() {
                        format!("Memory slot {slot_nr} cleared")
                    } else {
                        format!("Memory slot {slot_nr} updated ({} chars)", content.len())
                    }
                }
                Err(e) => format!("Error: {e}"),
            }
        }
        "gen_voice" => {
            let text = args["text"].as_str().unwrap_or("");
            if text.is_empty() {
                return "Error: text is required".to_string();
            }
            let script = tools_dir().join("gen_voice");
            let result = tokio::time::timeout(
                std::time::Duration::from_secs(120),
                tokio::process::Command::new(&script)
                    .arg(arguments)
                    .output(),
            )
            .await;
            match result {
                Ok(Ok(out)) if out.status.success() => {
                    let path_str = String::from_utf8_lossy(&out.stdout).trim().to_string();
                    let path = Path::new(&path_str);
                    if path.exists() {
                        let input_file = InputFile::file(path);
                        match bot.send_voice(chat_id, input_file).await {
                            Ok(_) => format!("语音已发送: {path_str}"),
                            Err(e) => format!("语音生成成功但发送失败: {e:#}"),
                        }
                    } else {
                        format!("语音生成失败: 输出文件不存在 ({path_str})")
                    }
                }
                Ok(Ok(out)) => {
                    let stderr = String::from_utf8_lossy(&out.stderr);
                    let stdout = String::from_utf8_lossy(&out.stdout);
                    format!("gen_voice failed: {stdout} {stderr}")
                }
                Ok(Err(e)) => format!("gen_voice exec error: {e}"),
                Err(_) => "gen_voice timeout (120s)".to_string(),
            }
        }
        _ => run_script_tool(name, arguments).await,
    }
}

async fn spawn_agent(
    id: &str,
    task: &str,
    state: &Arc<AppState>,
    bot: &Bot,
    chat_id: ChatId,
    sid: &str,
    config: &Arc<Config>,
) -> String {
    // check if already exists
    if state.agents.read().await.contains_key(id) {
        return format!("Agent '{id}' already exists. Use agent_status to check it.");
    }

    let mut child = match Command::new("claude")
        .args(["--dangerously-skip-permissions", "-p", task])
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()
    {
        Ok(c) => c,
        Err(e) => return format!("Failed to spawn agent: {e}"),
    };

    let pid = child.id();
    let output = Arc::new(tokio::sync::RwLock::new(String::new()));
    let completed = Arc::new(AtomicBool::new(false));
    let exit_code = Arc::new(tokio::sync::RwLock::new(None));

    let agent = Arc::new(SubAgent {
        task: task.to_string(),
        output: output.clone(),
        completed: completed.clone(),
        exit_code: exit_code.clone(),
        pid,
    });

    state.agents.write().await.insert(id.to_string(), agent);

    // background task: collect output and wakeup on completion
    let out = output.clone();
    let done = completed.clone();
    let ecode = exit_code.clone();
    let bot_c = bot.clone();
    let chat_id_c = chat_id;
    let state_c = state.clone();
    let config_c = config.clone();
    let sid_c = sid.to_string();
    let id_c = id.to_string();

    tokio::spawn(async move {
        let stdout = child.stdout.take();
        if let Some(stdout) = stdout {
            let mut lines = tokio::io::BufReader::new(stdout).lines();
            while let Ok(Some(line)) = lines.next_line().await {
                let mut o = out.write().await;
                o.push_str(&line);
                o.push('\n');
            }
        }
        let status = child.wait().await;
        let code = status.as_ref().ok().and_then(|s| s.code());
        *ecode.write().await = code;
        done.store(true, Ordering::SeqCst);

        info!(agent = %id_c, "agent completed, exit={code:?}");

        // wakeup: inject result and trigger LLM
        let result = out.read().await.clone();
        let result_short = truncate_at_char_boundary(&result, 4000);
        let wakeup = format!(
            "[Agent '{id_c}' 执行完成 (exit={})]\n{result_short}",
            code.unwrap_or(-1)
        );

        if let Err(e) = agent_wakeup(
            &config_c, &state_c, &bot_c, chat_id_c, &sid_c, &wakeup, &id_c,
        )
        .await
        {
            error!(agent = %id_c, "wakeup failed: {e:#}");
            let _ = bot_c
                .send_message(chat_id_c, format!("[agent wakeup error] {e:#}"))
                .await;
        }
    });

    format!("Agent '{id}' spawned (pid={pid:?})")
}

async fn agent_wakeup(
    config: &Config,
    state: &AppState,
    bot: &Bot,
    chat_id: ChatId,
    sid: &str,
    wakeup_msg: &str,
    agent_id: &str,
) -> Result<()> {
    match &config.backend {
        BackendConfig::OpenAI {
            endpoint,
            model,
            api_key,
        } => {
            state.push_message(sid, "user", wakeup_msg).await;
            let conv = state.load_conv(sid).await;
            let persona = state.get_config("persona").await.unwrap_or_default();
            let memory_slots = state.get_memory_slots().await;
            let system_msg = build_system_prompt(&conv.summary, &persona, &memory_slots);
            let mut api_messages = vec![system_msg];
            api_messages.extend(conv.messages);

            info!(agent = %agent_id, "wakeup: sending {} messages to LLM", api_messages.len());

            let response =
                run_openai_streaming(endpoint, model, api_key, &api_messages, bot, chat_id)
                    .await?;

            if !response.is_empty() {
                state.push_message(sid, "assistant", &response).await;
            }

            Ok(())
        }
        _ => {
            let _ = bot
                .send_message(chat_id, format!("[Agent '{agent_id}' done]\n{wakeup_msg}"))
                .await;
            Ok(())
        }
    }
}

async fn check_agent_status(id: &str, state: &AppState) -> String {
    let agents = state.agents.read().await;
    match agents.get(id) {
        Some(agent) => {
            let status = if agent.completed.load(Ordering::SeqCst) {
                let code = agent.exit_code.read().await;
                format!("completed (exit={})", code.unwrap_or(-1))
            } else {
                "running".to_string()
            };
            let output = agent.output.read().await;
            let out_preview = truncate_at_char_boundary(&output, 3000);
            format!(
                "Agent '{id}': {status}\nTask: {}\nOutput ({} bytes):\n{out_preview}",
                agent.task,
                output.len()
            )
        }
        None => format!("Agent '{id}' not found"),
    }
}

async fn kill_agent(id: &str, state: &AppState) -> String {
    let agents = state.agents.read().await;
    match agents.get(id) {
        Some(agent) => {
            if agent.completed.load(Ordering::SeqCst) {
                return format!("Agent '{id}' already completed");
            }
            if let Some(pid) = agent.pid {
                unsafe {
                    libc::kill(pid as i32, libc::SIGTERM);
                }
                format!("Sent SIGTERM to agent '{id}' (pid={pid})")
            } else {
                format!("Agent '{id}' has no PID")
            }
        }
        None => format!("Agent '{id}' not found"),
    }
}

async fn run_script_tool(name: &str, arguments: &str) -> String {
    // find script in tools/ that matches this tool name
    let dir = tools_dir();
    let entries = match std::fs::read_dir(&dir) {
        Ok(e) => e,
        Err(_) => return format!("Unknown tool: {name}"),
    };

    for entry in entries.flatten() {
        let path = entry.path();
        if !path.is_file() {
            continue;
        }
        // check if this script provides the requested tool
        let schema_out = std::process::Command::new(&path)
            .arg("--schema")
            .output();
        if let Ok(out) = schema_out {
            if out.status.success() {
                let stdout = String::from_utf8_lossy(&out.stdout);
                if let Ok(schema) = serde_json::from_str::<serde_json::Value>(stdout.trim()) {
                    if schema["name"].as_str() == Some(name) {
                        // found it — execute
                        info!(tool = %name, path = %path.display(), "running script tool");
                        let result = tokio::time::timeout(
                            std::time::Duration::from_secs(60),
                            Command::new(&path).arg(arguments).output(),
                        )
                        .await;

                        return match result {
                            Ok(Ok(output)) => {
                                let mut s = String::from_utf8_lossy(&output.stdout).to_string();
                                let stderr = String::from_utf8_lossy(&output.stderr);
                                if !stderr.is_empty() {
                                    if !s.is_empty() {
                                        s.push_str("\n[stderr]\n");
                                    }
                                    s.push_str(&stderr);
                                }
                                if s.is_empty() {
                                    format!("(exit={})", output.status.code().unwrap_or(-1))
                                } else {
                                    s
                                }
                            }
                            Ok(Err(e)) => format!("Failed to execute {name}: {e}"),
                            Err(_) => "Timeout after 60s".to_string(),
                        };
                    }
                }
            }
        }
    }

    format!("Unknown tool: {name}")
}

// ── openai with tool call loop ─────────────────────────────────────

#[allow(clippy::too_many_arguments)]
async fn run_openai_with_tools(
    endpoint: &str,
    model: &str,
    api_key: &str,
    mut messages: Vec<serde_json::Value>,
    bot: &Bot,
    chat_id: ChatId,
    state: &Arc<AppState>,
    sid: &str,
    config: &Arc<Config>,
    is_private: bool,
) -> Result<String> {
    let client = reqwest::Client::new();
    let url = format!("{}/chat/completions", endpoint.trim_end_matches('/'));
    let tools = discover_tools();

    loop {
        let body = serde_json::json!({
            "model": model,
            "messages": messages,
            "tools": tools,
            "stream": true,
        });

        info!("API request: {} messages, {} tools",
            messages.len(),
            tools.as_array().map(|a| a.len()).unwrap_or(0));

        let resp_raw = client
            .post(&url)
            .header("Authorization", format!("Bearer {api_key}"))
            .json(&body)
            .send()
            .await?;

        if !resp_raw.status().is_success() {
            let status = resp_raw.status();
            let body_text = resp_raw.text().await.unwrap_or_default();
            // dump messages for debugging
            for (i, m) in messages.iter().enumerate() {
                let role = m["role"].as_str().unwrap_or("?");
                let content_len = m["content"].as_str().map(|s| s.len()).unwrap_or(0);
                let has_tc = m.get("tool_calls").is_some();
                let has_tcid = m.get("tool_call_id").is_some();
                warn!("  msg[{i}] role={role} content_len={content_len} tool_calls={has_tc} tool_call_id={has_tcid}");
            }
            error!("OpenAI API {status}: {body_text}");
            anyhow::bail!("OpenAI API {status}: {body_text}");
        }

        let mut resp = resp_raw;

        let token = bot.token().to_owned();
        let raw_chat_id = chat_id.0;
        let draft_id: i64 = 1;
        let mut use_draft = is_private; // sendMessageDraft only works in private chats

        let mut msg_id: Option<teloxide::types::MessageId> = None;
        let mut accumulated = String::new();
        let mut last_edit = Instant::now();
        let mut buffer = String::new();
        let mut done = false;

        // tool call accumulation
        let mut tool_calls: Vec<ToolCall> = Vec::new();
        let mut has_tool_calls = false;

        while let Some(chunk) = resp.chunk().await? {
            if done {
                break;
            }
            buffer.push_str(&String::from_utf8_lossy(&chunk));

            while let Some(pos) = buffer.find('\n') {
                let line = buffer[..pos].to_string();
                buffer = buffer[pos + 1..].to_string();

                let trimmed = line.trim();
                if trimmed.is_empty() || trimmed.starts_with(':') {
                    continue;
                }

                let data = match trimmed.strip_prefix("data: ") {
                    Some(d) => d,
                    None => continue,
                };

                if data.trim() == "[DONE]" {
                    done = true;
                    break;
                }

                if let Ok(json) = serde_json::from_str::<serde_json::Value>(data) {
                    let delta = &json["choices"][0]["delta"];

                    // handle content delta
                    if let Some(content) = delta["content"].as_str() {
                        if !content.is_empty() {
                            accumulated.push_str(content);
                        }
                    }

                    // handle tool call delta
                    if let Some(tc_arr) = delta["tool_calls"].as_array() {
                        has_tool_calls = true;
                        for tc in tc_arr {
                            let idx = tc["index"].as_u64().unwrap_or(0) as usize;
                            while tool_calls.len() <= idx {
                                tool_calls.push(ToolCall {
                                    id: String::new(),
                                    name: String::new(),
                                    arguments: String::new(),
                                });
                            }
                            if let Some(id) = tc["id"].as_str() {
                                tool_calls[idx].id = id.to_string();
                            }
                            if let Some(name) = tc["function"]["name"].as_str() {
                                tool_calls[idx].name = name.to_string();
                            }
                            if let Some(args) = tc["function"]["arguments"].as_str() {
                                tool_calls[idx].arguments.push_str(args);
                            }
                        }
                    }

                    // display update (only when there's content to show)
                    if accumulated.is_empty() {
                        continue;
                    }

                    {

                        let interval = if use_draft {
                            DRAFT_INTERVAL_MS
                        } else {
                            EDIT_INTERVAL_MS
                        };
                        if last_edit.elapsed().as_millis() < interval as u128 {
                            continue;
                        }

                        let display = if use_draft {
                            truncate_at_char_boundary(&accumulated, TG_MSG_LIMIT).to_string()
                        } else {
                            truncate_for_display(&accumulated)
                        };

                        if use_draft {
                            match send_message_draft(
                                &client, &token, raw_chat_id, draft_id, &display,
                            )
                            .await
                            {
                                Ok(_) => {
                                    last_edit = Instant::now();
                                }
                                Err(e) => {
                                    warn!("sendMessageDraft failed, falling back: {e:#}");
                                    use_draft = false;
                                    if let Ok(sent) =
                                        bot.send_message(chat_id, &display).await
                                    {
                                        msg_id = Some(sent.id);
                                        last_edit = Instant::now();
                                    }
                                }
                            }
                        } else if let Some(id) = msg_id {
                            if bot
                                .edit_message_text(chat_id, id, &display)
                                .await
                                .is_ok()
                            {
                                last_edit = Instant::now();
                            }
                        } else if let Ok(sent) =
                            bot.send_message(chat_id, &display).await
                        {
                            msg_id = Some(sent.id);
                            last_edit = Instant::now();
                        }
                    } // end display block
                }
            }
        }

        // decide what to do based on response type
        if has_tool_calls && !tool_calls.is_empty() {
            // append assistant message with tool calls
            let tc_json: Vec<serde_json::Value> = tool_calls
                .iter()
                .map(|tc| {
                    serde_json::json!({
                        "id": tc.id,
                        "type": "function",
                        "function": {
                            "name": tc.name,
                            "arguments": tc.arguments,
                        }
                    })
                })
                .collect();

            let assistant_msg = serde_json::json!({
                "role": "assistant",
                "content": if accumulated.is_empty() { "" } else { &accumulated },
                "tool_calls": tc_json,
            });
            messages.push(assistant_msg);

            // execute each tool
            for tc in &tool_calls {
                info!(tool = %tc.name, "executing tool call");
                let _ = bot
                    .send_message(chat_id, format!("[{}({})]", tc.name, truncate_at_char_boundary(&tc.arguments, 100)))
                    .await;

                let result =
                    execute_tool(&tc.name, &tc.arguments, state, bot, chat_id, sid, config)
                        .await;

                messages.push(serde_json::json!({
                    "role": "tool",
                    "tool_call_id": tc.id,
                    "content": result,
                }));
            }

            // clear display state for next round
            tool_calls.clear();
            // loop back to call API again
            continue;
        }

        // content response — send final result
        if !accumulated.is_empty() {
            send_final_result(bot, chat_id, msg_id, use_draft, &accumulated).await;
        }

        return Ok(accumulated);
    }
}

// ── claude bridge (streaming) ───────────────────────────────────────

/// Stream JSON event types we care about.
#[derive(Deserialize)]
struct StreamEvent {
    #[serde(rename = "type")]
    event_type: String,
    message: Option<AssistantMessage>,
    result: Option<String>,
    #[serde(default)]
    is_error: bool,
}

#[derive(Deserialize)]
struct AssistantMessage {
    content: Vec<ContentBlock>,
}

#[derive(Deserialize)]
struct ContentBlock {
    #[serde(rename = "type")]
    block_type: String,
    text: Option<String>,
    name: Option<String>,
    input: Option<serde_json::Value>,
}

/// Extract all text from an assistant message's content blocks.
fn extract_text(msg: &AssistantMessage) -> String {
    msg.content
        .iter()
        .filter(|b| b.block_type == "text")
        .filter_map(|b| b.text.as_deref())
        .collect::<Vec<_>>()
        .join("")
}

/// Extract tool use status line, e.g. "Bash: echo hello"
fn extract_tool_use(msg: &AssistantMessage) -> Option<String> {
    for block in &msg.content {
        if block.block_type == "tool_use" {
            let name = block.name.as_deref().unwrap_or("tool");
            let detail = block
                .input
                .as_ref()
                .and_then(|v| {
                    // try common fields: command, pattern, file_path, query
                    v.get("command")
                        .or(v.get("pattern"))
                        .or(v.get("file_path"))
                        .or(v.get("query"))
                        .or(v.get("prompt"))
                        .and_then(|s| s.as_str())
                })
                .unwrap_or("");
            let detail_short = truncate_at_char_boundary(detail, 80);
            return Some(format!("{name}: {detail_short}"));
        }
    }
    None
}

const EDIT_INTERVAL_MS: u64 = 2000;
const DRAFT_INTERVAL_MS: u64 = 1000;
const TG_MSG_LIMIT: usize = 4096;

async fn invoke_claude_streaming(
    sid: &str,
    prompt: &str,
    known: bool,
    bot: &Bot,
    chat_id: ChatId,
) -> Result<String> {
    if known {
        return run_claude_streaming(&["--resume", sid], prompt, bot, chat_id).await;
    }

    match run_claude_streaming(&["--resume", sid], prompt, bot, chat_id).await {
        Ok(out) => {
            info!(%sid, "resumed existing session");
            Ok(out)
        }
        Err(e) => {
            warn!(%sid, "resume failed ({e:#}), creating new session");
            run_claude_streaming(&["--session-id", sid], prompt, bot, chat_id).await
        }
    }
}

async fn send_message_draft(
    client: &reqwest::Client,
    token: &str,
    chat_id: i64,
    draft_id: i64,
    text: &str,
) -> Result<()> {
    let url = format!("https://api.telegram.org/bot{token}/sendMessageDraft");
    let resp = client
        .post(&url)
        .json(&serde_json::json!({
            "chat_id": chat_id,
            "draft_id": draft_id,
            "text": text,
        }))
        .send()
        .await?;
    let body: serde_json::Value = resp.json().await?;
    if body["ok"].as_bool() != Some(true) {
        anyhow::bail!("sendMessageDraft: {}", body);
    }
    Ok(())
}

async fn run_claude_streaming(
    extra_args: &[&str],
    prompt: &str,
    bot: &Bot,
    chat_id: ChatId,
) -> Result<String> {
    let mut args: Vec<&str> = vec![
        "--dangerously-skip-permissions",
        "-p",
        "--output-format",
        "stream-json",
        "--verbose",
    ];
    args.extend(extra_args);
    args.push(prompt);

    let mut child = Command::new("claude")
        .args(&args)
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()?;

    let stdout = child.stdout.take().unwrap();
    let mut lines = tokio::io::BufReader::new(stdout).lines();

    // sendMessageDraft for native streaming, with editMessageText fallback
    let http = reqwest::Client::new();
    let token = bot.token().to_owned();
    let raw_chat_id = chat_id.0;
    let draft_id: i64 = 1;
    let mut use_draft = true;

    let mut msg_id: Option<teloxide::types::MessageId> = None;
    let mut last_sent_text = String::new();
    let mut last_edit = Instant::now();
    let mut final_result = String::new();
    let mut is_error = false;
    let mut tool_status = String::new();

    while let Ok(Some(line)) = lines.next_line().await {
        let event: StreamEvent = match serde_json::from_str(&line) {
            Ok(e) => e,
            Err(_) => continue,
        };

        match event.event_type.as_str() {
            "assistant" => {
                if let Some(amsg) = &event.message {
                    // determine display content
                    let (display_raw, new_text) =
                        if let Some(status) = extract_tool_use(amsg) {
                            tool_status = format!("[{status}]");
                            let d = if last_sent_text.is_empty() {
                                tool_status.clone()
                            } else {
                                format!("{last_sent_text}\n\n{tool_status}")
                            };
                            (d, None)
                        } else {
                            let text = extract_text(amsg);
                            if text.is_empty() || text == last_sent_text {
                                continue;
                            }
                            let interval = if use_draft {
                                DRAFT_INTERVAL_MS
                            } else {
                                EDIT_INTERVAL_MS
                            };
                            if last_edit.elapsed().as_millis() < interval as u128 {
                                continue;
                            }
                            tool_status.clear();
                            (text.clone(), Some(text))
                        };

                    let display = if use_draft {
                        // draft mode: no cursor — cursor breaks monotonic text growth
                        truncate_at_char_boundary(&display_raw, TG_MSG_LIMIT).to_string()
                    } else {
                        truncate_for_display(&display_raw)
                    };

                    if use_draft {
                        match send_message_draft(
                            &http, &token, raw_chat_id, draft_id, &display,
                        )
                        .await
                        {
                            Ok(_) => {
                                if let Some(t) = new_text {
                                    last_sent_text = t;
                                }
                                last_edit = Instant::now();
                            }
                            Err(e) => {
                                warn!("sendMessageDraft failed, falling back: {e:#}");
                                use_draft = false;
                                if let Ok(sent) =
                                    bot.send_message(chat_id, &display).await
                                {
                                    msg_id = Some(sent.id);
                                    if let Some(t) = new_text {
                                        last_sent_text = t;
                                    }
                                    last_edit = Instant::now();
                                }
                            }
                        }
                    } else if let Some(id) = msg_id {
                        if bot
                            .edit_message_text(chat_id, id, &display)
                            .await
                            .is_ok()
                        {
                            if let Some(t) = new_text {
                                last_sent_text = t;
                            }
                            last_edit = Instant::now();
                        }
                    } else if let Ok(sent) =
                        bot.send_message(chat_id, &display).await
                    {
                        msg_id = Some(sent.id);
                        if let Some(t) = new_text {
                            last_sent_text = t;
                        }
                        last_edit = Instant::now();
                    }
                }
            }
            "result" => {
                final_result = event.result.unwrap_or_default();
                is_error = event.is_error;
            }
            _ => {}
        }
    }

    // read stderr before waiting (in case child already exited)
    let stderr_handle = child.stderr.take();
    let status = child.wait().await;

    // collect stderr for diagnostics
    let stderr_text = if let Some(mut se) = stderr_handle {
        let mut buf = String::new();
        let _ = tokio::io::AsyncReadExt::read_to_string(&mut se, &mut buf).await;
        buf
    } else {
        String::new()
    };

    // determine error: explicit is_error from stream, or non-zero exit with no result
    let has_error = is_error
        || (final_result.is_empty()
            && status.as_ref().map(|s| !s.success()).unwrap_or(true));

    if has_error {
        let err_detail = if !final_result.is_empty() {
            final_result.clone()
        } else if !stderr_text.is_empty() {
            stderr_text.trim().to_string()
        } else {
            format!("claude exited: {:?}", status)
        };
        if !use_draft {
            if let Some(id) = msg_id {
                let _ = bot
                    .edit_message_text(chat_id, id, format!("[error] {err_detail}"))
                    .await;
            }
        }
        anyhow::bail!("{err_detail}");
    }

    if final_result.is_empty() {
        return Ok(final_result);
    }

    send_final_result(bot, chat_id, msg_id, use_draft, &final_result).await;

    Ok(final_result)
}

// ── openai-compatible backend (streaming) ──────────────────────────

async fn run_openai_streaming(
    endpoint: &str,
    model: &str,
    api_key: &str,
    messages: &[serde_json::Value],
    bot: &Bot,
    chat_id: ChatId,
) -> Result<String> {
    let client = reqwest::Client::new();
    let url = format!("{}/chat/completions", endpoint.trim_end_matches('/'));

    let body = serde_json::json!({
        "model": model,
        "messages": messages,
        "stream": true,
    });

    let mut resp = client
        .post(&url)
        .header("Authorization", format!("Bearer {api_key}"))
        .json(&body)
        .send()
        .await?
        .error_for_status()?;

    let token = bot.token().to_owned();
    let raw_chat_id = chat_id.0;
    let draft_id: i64 = 1;
    let mut use_draft = true;

    let mut msg_id: Option<teloxide::types::MessageId> = None;
    let mut accumulated = String::new();
    let mut last_edit = Instant::now();
    let mut buffer = String::new();
    let mut done = false;

    while let Some(chunk) = resp.chunk().await? {
        if done {
            break;
        }
        buffer.push_str(&String::from_utf8_lossy(&chunk));

        while let Some(pos) = buffer.find('\n') {
            let line = buffer[..pos].to_string();
            buffer = buffer[pos + 1..].to_string();

            let trimmed = line.trim();
            if trimmed.is_empty() || trimmed.starts_with(':') {
                continue;
            }

            let data = match trimmed.strip_prefix("data: ") {
                Some(d) => d,
                None => continue,
            };

            if data.trim() == "[DONE]" {
                done = true;
                break;
            }

            if let Ok(json) = serde_json::from_str::<serde_json::Value>(data) {
                if let Some(content) = json["choices"][0]["delta"]["content"].as_str() {
                    if content.is_empty() {
                        continue;
                    }
                    accumulated.push_str(content);

                    let interval = if use_draft {
                        DRAFT_INTERVAL_MS
                    } else {
                        EDIT_INTERVAL_MS
                    };
                    if last_edit.elapsed().as_millis() < interval as u128 {
                        continue;
                    }

                    let display = if use_draft {
                        truncate_at_char_boundary(&accumulated, TG_MSG_LIMIT).to_string()
                    } else {
                        truncate_for_display(&accumulated)
                    };

                    if use_draft {
                        match send_message_draft(
                            &client, &token, raw_chat_id, draft_id, &display,
                        )
                        .await
                        {
                            Ok(_) => {
                                last_edit = Instant::now();
                            }
                            Err(e) => {
                                warn!("sendMessageDraft failed, falling back: {e:#}");
                                use_draft = false;
                                if let Ok(sent) = bot.send_message(chat_id, &display).await {
                                    msg_id = Some(sent.id);
                                    last_edit = Instant::now();
                                }
                            }
                        }
                    } else if let Some(id) = msg_id {
                        if bot.edit_message_text(chat_id, id, &display).await.is_ok() {
                            last_edit = Instant::now();
                        }
                    } else if let Ok(sent) = bot.send_message(chat_id, &display).await {
                        msg_id = Some(sent.id);
                        last_edit = Instant::now();
                    }
                }
            }
        }
    }

    if accumulated.is_empty() {
        return Ok(accumulated);
    }

    send_final_result(bot, chat_id, msg_id, use_draft, &accumulated).await;

    Ok(accumulated)
}

const CURSOR: &str = " \u{25CE}";

fn truncate_for_display(s: &str) -> String {
    let budget = TG_MSG_LIMIT - CURSOR.len() - 1;
    if s.len() <= budget {
        format!("{s}{CURSOR}")
    } else {
        let truncated = truncate_at_char_boundary(s, budget - 2);
        format!("{truncated}\n…{CURSOR}")
    }
}

fn truncate_at_char_boundary(s: &str, max: usize) -> &str {
    if s.len() <= max {
        return s;
    }
    let mut end = max;
    while !s.is_char_boundary(end) {
        end -= 1;
    }
    &s[..end]
}

fn escape_html(s: &str) -> String {
    s.replace('&', "&amp;")
        .replace('<', "&lt;")
        .replace('>', "&gt;")
        .replace('"', "&quot;")
}

fn markdown_to_telegram_html(md: &str) -> String {
    use pulldown_cmark::{CodeBlockKind, Event, Options, Parser, Tag, TagEnd};

    let mut opts = Options::empty();
    opts.insert(Options::ENABLE_STRIKETHROUGH);

    let parser = Parser::new_ext(md, opts);
    let mut html = String::new();

    for event in parser {
        match event {
            Event::Start(tag) => match tag {
                Tag::Paragraph => {}
                Tag::Heading { .. } => html.push_str("<b>"),
                Tag::BlockQuote(_) => html.push_str("<blockquote>"),
                Tag::CodeBlock(kind) => match kind {
                    CodeBlockKind::Fenced(ref lang) if !lang.is_empty() => {
                        html.push_str(&format!(
                            "<pre><code class=\"language-{}\">",
                            escape_html(lang.as_ref())
                        ));
                    }
                    _ => html.push_str("<pre><code>"),
                },
                Tag::Item => html.push_str("• "),
                Tag::Emphasis => html.push_str("<i>"),
                Tag::Strong => html.push_str("<b>"),
                Tag::Strikethrough => html.push_str("<s>"),
                Tag::Link { dest_url, .. } => {
                    html.push_str(&format!(
                        "<a href=\"{}\">",
                        escape_html(dest_url.as_ref())
                    ));
                }
                _ => {}
            },
            Event::End(tag) => match tag {
                TagEnd::Paragraph => html.push_str("\n\n"),
                TagEnd::Heading(_) => html.push_str("</b>\n\n"),
                TagEnd::BlockQuote(_) => html.push_str("</blockquote>"),
                TagEnd::CodeBlock => html.push_str("</code></pre>\n\n"),
                TagEnd::List(_) => html.push('\n'),
                TagEnd::Item => html.push('\n'),
                TagEnd::Emphasis => html.push_str("</i>"),
                TagEnd::Strong => html.push_str("</b>"),
                TagEnd::Strikethrough => html.push_str("</s>"),
                TagEnd::Link => html.push_str("</a>"),
                _ => {}
            },
            Event::Text(text) => html.push_str(&escape_html(text.as_ref())),
            Event::Code(text) => {
                html.push_str("<code>");
                html.push_str(&escape_html(text.as_ref()));
                html.push_str("</code>");
            }
            Event::SoftBreak | Event::HardBreak => html.push('\n'),
            Event::Rule => html.push_str("\n---\n\n"),
            _ => {}
        }
    }

    html.trim_end().to_string()
}

/// Send final result with HTML formatting, fallback to plain text on failure.
async fn send_final_result(
    bot: &Bot,
    chat_id: ChatId,
    msg_id: Option<teloxide::types::MessageId>,
    use_draft: bool,
    result: &str,
) {
    use teloxide::types::ParseMode;

    let html = markdown_to_telegram_html(result);

    // try HTML as single message
    let html_ok = if let (false, Some(id)) = (use_draft, msg_id) {
        bot.edit_message_text(chat_id, id, &html)
            .parse_mode(ParseMode::Html)
            .await
            .is_ok()
    } else {
        bot.send_message(chat_id, &html)
            .parse_mode(ParseMode::Html)
            .await
            .is_ok()
    };

    if html_ok {
        return;
    }

    // fallback: plain text with chunking
    let chunks = split_msg(result, TG_MSG_LIMIT);
    if let (false, Some(id)) = (use_draft, msg_id) {
        let _ = bot.edit_message_text(chat_id, id, chunks[0]).await;
        for chunk in &chunks[1..] {
            let _ = bot.send_message(chat_id, *chunk).await;
        }
    } else {
        for chunk in &chunks {
            let _ = bot.send_message(chat_id, *chunk).await;
        }
    }
}

fn split_msg(s: &str, max: usize) -> Vec<&str> {
    if s.len() <= max {
        return vec![s];
    }
    let mut parts = Vec::new();
    let mut rest = s;
    while !rest.is_empty() {
        if rest.len() <= max {
            parts.push(rest);
            break;
        }
        let mut end = max;
        while !rest.is_char_boundary(end) {
            end -= 1;
        }
        let (chunk, tail) = rest.split_at(end);
        parts.push(chunk);
        rest = tail;
    }
    parts
}