// 大腦: one AnyBot of the account keeps the bots, chats, memory and schedules (the brain, usually
// `anybot --serve` next to the account server). Every other AnyBot signed in to the account shows
// the brain's bots in its own window and lends its hands (screen, files, browser) through 裝置連結.
//
// The brain side answers "what changed since version N?" per screen: the settings (bots without
// their chats) when they changed, and for each bot only the messages from the first one that
// changed. The screen side keeps a copy, sends the person's edits back as small operations, and
// turns chat actions (send, stop, approve…) into requests. When the brain can't be reached the
// window stays readable and waits.

use super::*;
use crate::remote::{self, SyncKind};
use serde_json::{json, Value};
use std::hash::{Hash, Hasher};
use std::sync::atomic::AtomicU64;

/// Settings that belong to each computer, never to the brain.
const LOCAL_KEYS: &[&str] = &["remote", "theme", "accent", "sidebar_collapsed", "sidebar_width", "selected", "machine_label", "local_execution", "local_never", "messages_send", "messages_no_ask"];
/// Bot fields the brain alone changes (its chat, and what a turn leaves behind).
const BOT_RUNTIME: &[&str] = &["id", "messages", "threads", "unread", "last_turn", "context_tokens"];
/// Stands in for a key or token the brain doesn't hand out.
pub const REDACTED: &str = "••••（已設定，在大腦上）";

// ---------- shared ----------

/// The settings as JSON: everything but the chats (messages and earlier conversations).
pub(super) fn config_json(st: &mut State) -> Value {
    let mut bots = std::mem::take(&mut st.bots);
    let mut top = serde_json::to_value(&*st).unwrap_or(Value::Null);
    let mut arr = Vec::with_capacity(bots.len());
    for b in bots.iter_mut() {
        let m = std::mem::take(&mut b.messages);
        let th = std::mem::take(&mut b.threads);
        arr.push(serde_json::to_value(&*b).unwrap_or(Value::Null));
        b.messages = m;
        b.threads = th;
    }
    st.bots = bots;
    top["bots"] = Value::Array(arr);
    top
}

/// Keys and tokens stay on the brain.
fn redact(top: &mut Value) {
    if let Some(o) = top.as_object_mut() {
        o.remove("remote");
    }
    let hide = |v: &mut Value| {
        if v.as_str().map(|s| !s.is_empty()).unwrap_or(false) {
            *v = Value::String(REDACTED.into());
        }
    };
    if let Some(ps) = top["providers"].as_object_mut() {
        for p in ps.values_mut() {
            hide(&mut p["api_key"]);
        }
    }
    for c in top["channels"].as_array_mut().into_iter().flatten() {
        hide(&mut c["token"]);
    }
    for m in top["mcp_servers"].as_array_mut().into_iter().flatten() {
        for k in ["env", "headers"] {
            for v in m[k].as_object_mut().into_iter().flat_map(|o| o.values_mut()) {
                hide(v);
            }
        }
    }
}

/// Put the brain's own keys back wherever an edit still carries the stand-in.
fn unredact(new: &mut Value, old: &Value) {
    match new {
        Value::String(s) if s == REDACTED => *new = old.clone(),
        Value::Object(o) => {
            for (k, v) in o.iter_mut() {
                unredact(v, old.get(k).unwrap_or(&Value::Null));
            }
        }
        Value::Array(a) => {
            for (i, v) in a.iter_mut().enumerate() {
                let key = |x: &Value| x.get("id").cloned().filter(|x| !x.is_null()).or_else(|| x.get("name").cloned());
                let twin = old.as_array().and_then(|olds| match key(v) {
                    Some(k) => olds.iter().find(|o| key(o).as_ref() == Some(&k)),
                    None => olds.get(i),
                });
                unredact(v, twin.unwrap_or(&Value::Null));
            }
        }
        _ => {}
    }
}

/// A cheap fingerprint of one message: enough to see it changed (streaming, a tool finishing…).
fn msg_sig(m: &Message) -> u64 {
    let mut h = std::collections::hash_map::DefaultHasher::new();
    (m.role as u8, m.text.len(), m.thinking.len(), m.error, m.summary, m.images.len(), m.attachments.len(), m.at, &m.tool_call_id, &m.reactions).hash(&mut h);
    m.text.chars().rev().take(48).collect::<String>().hash(&mut h);
    for c in &m.tool_calls {
        (&c.id, c.args.len(), c.status as u8).hash(&mut h);
    }
    h.finish()
}

fn threads_sig(b: &Bot) -> u64 {
    let mut h = std::collections::hash_map::DefaultHasher::new();
    for (t, msgs) in &b.threads {
        (t, msgs.len()).hash(&mut h);
    }
    h.finish()
}

fn hash_value(v: &Value) -> u64 {
    let mut h = std::collections::hash_map::DefaultHasher::new();
    v.to_string().hash(&mut h);
    h.finish()
}

/// What names an item in a list: its id, else its name, else (plain values) the value itself.
fn item_key(x: &Value) -> Option<Value> {
    match x {
        Value::Object(o) => o.get("id").filter(|v| !v.is_null()).or_else(|| o.get("name").filter(|v| v.is_string())).cloned(),
        Value::Array(_) | Value::Null => None,
        v => Some(v.clone()),
    }
}

/// Every item has its own key, and no two share one.
fn keyed(a: &[Value]) -> bool {
    let mut seen = std::collections::HashSet::new();
    a.iter().all(|x| item_key(x).map(|k| seen.insert(k.to_string())).unwrap_or(false))
}

/// The smallest change from `old` to `new`: lists of named things and maps change item by item,
/// so two computers editing different items of one list don't undo each other.
pub(super) fn patch_of(old: &Value, new: &Value) -> Value {
    match (old, new) {
        (Value::Object(o), Value::Object(n)) => {
            let put: serde_json::Map<String, Value> = n.iter().filter(|(k, v)| o.get(*k) != Some(*v)).map(|(k, v)| (k.clone(), v.clone())).collect();
            let del: Vec<&String> = o.keys().filter(|k| !n.contains_key(*k)).collect();
            json!({"map": {"put": put, "del": del}})
        }
        (Value::Array(o), Value::Array(n)) if keyed(o) && keyed(n) => {
            let key = |x: &Value| item_key(x).unwrap_or(Value::Null);
            let put: Vec<&Value> = n.iter().filter(|x| !o.iter().any(|y| key(y) == key(x) && y == *x)).collect();
            let del: Vec<Value> = o.iter().map(key).filter(|k| !n.iter().any(|x| key(x) == *k)).collect();
            let common_old: Vec<Value> = o.iter().map(key).filter(|k| n.iter().any(|x| key(x) == *k)).collect();
            let common_new: Vec<Value> = n.iter().map(key).filter(|k| o.iter().any(|x| key(x) == *k)).collect();
            let mut p = json!({"list": {"put": put, "del": del}});
            if common_old != common_new {
                p["list"]["order"] = Value::Array(n.iter().map(key).collect());
            }
            p
        }
        _ => json!({"value": new}),
    }
}

/// Apply a change made by `patch_of` to whatever the value is now.
pub(super) fn apply_patch(cur: &mut Value, p: &Value) {
    if let Some(v) = p.get("value") {
        *cur = v.clone();
    } else if let Some(m) = p.get("map") {
        if !cur.is_object() {
            *cur = json!({});
        }
        let o = cur.as_object_mut().expect("object");
        for (k, v) in m["put"].as_object().into_iter().flatten() {
            o.insert(k.clone(), v.clone());
        }
        for k in m["del"].as_array().into_iter().flatten().filter_map(Value::as_str) {
            o.remove(k);
        }
    } else if let Some(l) = p.get("list") {
        if !cur.is_array() {
            *cur = json!([]);
        }
        let a = cur.as_array_mut().expect("array");
        let key = |x: &Value| item_key(x).unwrap_or(Value::Null);
        for item in l["put"].as_array().into_iter().flatten() {
            match a.iter_mut().find(|x| key(x) == key(item)) {
                Some(x) => *x = item.clone(),
                None => a.push(item.clone()),
            }
        }
        let del: Vec<Value> = l["del"].as_array().cloned().unwrap_or_default();
        a.retain(|x| !del.contains(&key(x)));
        if let Some(order) = l["order"].as_array() {
            a.sort_by_key(|x| order.iter().position(|k| *k == key(x)).unwrap_or(usize::MAX));
        }
    }
}

/// The person's edits since `base`, as operations the brain applies one by one.
pub(super) fn diff_ops(base: &Value, cur: &Value) -> Vec<Value> {
    let mut ops = vec![];
    let (Some(b), Some(c)) = (base.as_object(), cur.as_object()) else { return ops };
    for (k, v) in c {
        if k == "bots" || LOCAL_KEYS.contains(&k.as_str()) {
            continue;
        }
        if b.get(k) != Some(v) {
            let p = patch_of(b.get(k).unwrap_or(&Value::Null), v);
            ops.push(if p.get("value").is_some() { json!({"op": "set", "key": k, "value": v}) } else { json!({"op": "patch", "key": k, "patch": p}) });
        }
    }
    let id = |x: &Value| x["id"].as_u64().unwrap_or(0);
    let empty = vec![];
    let old = base["bots"].as_array().unwrap_or(&empty);
    let new = cur["bots"].as_array().unwrap_or(&empty);
    for nb in new {
        match old.iter().find(|o| id(o) == id(nb)) {
            None => ops.push(json!({"op": "bot_add", "bot": nb})),
            Some(ob) => {
                for (k, v) in nb.as_object().into_iter().flatten() {
                    if k == "unread" {
                        if ob[k] == true && *v == false {
                            ops.push(json!({"op": "bot_read", "id": id(nb)}));
                        }
                        continue;
                    }
                    if BOT_RUNTIME.contains(&k.as_str()) {
                        continue;
                    }
                    if ob.get(k) != Some(v) {
                        let p = patch_of(ob.get(k).unwrap_or(&Value::Null), v);
                        ops.push(if p.get("value").is_some() { json!({"op": "bot_set", "id": id(nb), "key": k, "value": v}) } else { json!({"op": "bot_patch", "id": id(nb), "key": k, "patch": p}) });
                    }
                }
            }
        }
    }
    for ob in old {
        if !new.iter().any(|n| id(n) == id(ob)) {
            ops.push(json!({"op": "bot_del", "id": id(ob)}));
        }
    }
    let order = |a: &Vec<Value>| a.iter().map(id).collect::<Vec<_>>();
    let (oo, no) = (order(old), order(new));
    let kept: Vec<u64> = oo.iter().copied().filter(|i| no.contains(i)).collect();
    let kept_new: Vec<u64> = no.iter().copied().filter(|i| oo.contains(i)).collect();
    if kept != kept_new {
        ops.push(json!({"op": "bot_order", "ids": no}));
    }
    ops
}

/// Replay edit operations on settings JSON: a screen keeps its own not-yet-confirmed edits on
/// top of what the brain last sent, so typing isn't undone by the brain's slightly older copy.
pub(super) fn apply_ops(cfg: &mut Value, ops: &[Value]) {
    let id = |x: &Value| x["id"].as_u64().unwrap_or(0);
    for op in ops {
        let target = op["id"].as_u64().unwrap_or(0);
        match op["op"].as_str().unwrap_or("") {
            "set" => {
                if let Some(k) = op["key"].as_str() {
                    cfg[k] = op["value"].clone();
                }
            }
            "patch" => {
                if let Some(k) = op["key"].as_str() {
                    apply_patch(&mut cfg[k], &op["patch"]);
                }
            }
            "bot_patch" => {
                if let (Some(b), Some(k)) = (cfg["bots"].as_array_mut().and_then(|a| a.iter_mut().find(|b| id(b) == target)), op["key"].as_str()) {
                    apply_patch(&mut b[k], &op["patch"]);
                }
            }
            "bot_add" => {
                if let Some(a) = cfg["bots"].as_array_mut() {
                    if !a.iter().any(|b| id(b) == id(&op["bot"])) {
                        a.push(op["bot"].clone());
                    }
                }
            }
            "bot_del" => {
                if let Some(a) = cfg["bots"].as_array_mut() {
                    a.retain(|b| id(b) != target);
                }
            }
            "bot_set" | "bot_read" => {
                if let Some(b) = cfg["bots"].as_array_mut().and_then(|a| a.iter_mut().find(|b| id(b) == target)) {
                    if op["op"] == "bot_read" {
                        b["unread"] = json!(false);
                    } else if let Some(k) = op["key"].as_str() {
                        b[k] = op["value"].clone();
                    }
                }
            }
            "bot_order" => {
                let ids: Vec<u64> = op["ids"].as_array().into_iter().flatten().filter_map(Value::as_u64).collect();
                if let Some(a) = cfg["bots"].as_array_mut() {
                    a.sort_by_key(|b| ids.iter().position(|i| *i == id(b)).unwrap_or(usize::MAX));
                }
            }
            _ => {}
        }
    }
}

/// A schedule edited on a screen keeps what the brain knows about runs (when it last ran, when it
/// runs next), so an older copy can't make a routine run twice.
fn keep_run_times(new: &mut Value, old: &Value) {
    for r in new.as_array_mut().into_iter().flatten() {
        let Some(o) = old.as_array().and_then(|a| a.iter().find(|o| o["id"] == r["id"])) else { continue };
        let last = |x: &Value| x["last_run"].as_i64();
        if last(o) > last(r) || r["last_run"].is_null() {
            r["last_run"] = o["last_run"].clone();
        }
        let same = ["schedule", "trigger", "paused"].iter().all(|k| r[*k] == o[*k]);
        if same {
            r["next_run"] = o["next_run"].clone();
        }
    }
}

// ---------- the brain's side ----------

/// What the brain last sent each screen.
#[derive(Default)]
pub struct Screens {
    seen: HashMap<String, Seen>,
    /// The settings fingerprint, refreshed now and then while something changes.
    pub(super) cfg_hash: u64,
    cfg_at: Option<Instant>,
    /// The last edit (by number) each screen sent, so it knows which of its edits are in.
    acked: HashMap<String, u64>,
}

#[derive(Default)]
struct Seen {
    version: u64,
    config: u64,
    bots: HashMap<u64, Vec<u64>>,
    threads: HashMap<u64, u64>,
    at: Option<Instant>,
}

// ---------- the screen's side ----------

pub enum Incoming {
    Pull(Value),
    Offline(String),
    /// A file from the brain arrived (its local copy's path).
    File(String),
}

/// What a screen sends to the brain, one at a time and in order.
enum Out {
    Edit { seq: u64, ops: Vec<Value> },
    Act(Value),
    Send { bot: u64, text: String, atts: Vec<crate::attach::Attachment> },
    Move { ops: Vec<Value>, n: usize },
}

#[derive(Default)]
pub struct Mirror {
    /// This window shows a brain (instead of its own bots).
    pub on: bool,
    /// Heard from the brain lately.
    pub online: bool,
    /// The brain's settings as last received (edits are what differs from this).
    pub(super) base: Value,
    pub status: Arc<Mutex<String>>,
    rx: Option<Receiver<Incoming>>,
    tx: Option<Sender<Incoming>>,
    gen: Arc<AtomicU64>,
    version: Arc<AtomicU64>,
    client: String,
    /// This computer's own data, kept aside while it shows the brain.
    local: Option<State>,
    started: bool,
    /// A request to the brain failed (shown above the message box).
    pub(super) error: Arc<Mutex<String>>,
    /// The person chose a brain in 設定 (applied on the next frame).
    pub(super) want: Option<(String, String)>,
    pub(super) leave: bool,
    pub(super) moving: Arc<AtomicBool>,
    /// Just signed in: copy this computer's bots to the brain once it answers.
    pub(super) move_after_join: bool,
    pub(super) move_note: Arc<Mutex<String>>,
    /// Requests to the brain, sent in order by one worker.
    outbox: Option<Sender<Out>>,
    /// Edits sent but not yet confirmed (by number).
    pending: Arc<Mutex<Vec<(u64, Vec<Value>)>>>,
    seq: u64,
    /// Something didn't reach the brain: ask for everything again.
    resync: Arc<AtomicBool>,
    /// Why the brain can't be reached (shown above the chat), and since when.
    pub(super) reason: String,
    down_since: Option<Instant>,
    /// Files from the brain being fetched (by local path).
    fetching: std::collections::HashSet<String>,
    /// 加一台電腦: the line to run on the new computer (or why there is none), and when it was made.
    pub(super) pair: Arc<Mutex<(String, bool, Option<Instant>)>>,
    /// The bots' own computer on the brain: {label, running, available, busy}.
    pub(super) box_state: Value,
    /// Each bot's computers on the brain, by bot id: {names: [{name, kind}], current, missing}.
    pub(super) computers: HashMap<u64, Value>,
}

/// What a computer is, in a word a screen can show next to its name.
pub(super) fn computer_kind(t: &crate::tools::Target, r: &crate::tools::Roles) -> &'static str {
    use crate::tools::Place;
    if t.name == r.own {
        "own"
    } else if r.person.as_deref() == Some(t.name.as_str()) {
        "person"
    } else {
        match t.place {
            Place::Local { .. } if r.server => "server",
            Place::Local { .. } => "this",
            Place::Device { .. } => "device",
            _ => "ssh",
        }
    }
}

/// Where a screen keeps its copy of a file the brain has.
fn local_copy(brain_path: &str, name: &str) -> PathBuf {
    let h = crate::httpd::sha256_hex(brain_path);
    let name: String = name.chars().filter(|c| !matches!(c, '/' | '\\' | '\0' | ':')).take(80).collect();
    State::path().with_file_name("brain-files").join(format!("{}-{name}", &h[..16]))
}

fn cache_path() -> PathBuf {
    State::path().with_file_name("brain-copy.json")
}

impl App {
    /// The brain: answer the screens' requests (on the app's thread, where the state is).
    pub(super) fn brain_serve(&mut self) {
        let reqs = remote::hub().take_sync();
        if reqs.is_empty() {
            return;
        }
        for r in reqs {
            let v = match r.kind {
                SyncKind::Pull { client, since } => self.brain_pull(&client, since),
                SyncKind::Models(name) => {
                    let kind = serde_json::from_value::<crate::providers::ProviderKind>(json!(name)).ok();
                    match kind {
                        Some(kind) => {
                            let ps = self.state.provider(kind);
                            let (base, key) = (crate::providers::resolve_base(kind, &ps.base_url), crate::providers::resolve_key(kind, &ps.api_key));
                            let reply = r.reply;
                            // The list can take a while; the app doesn't wait for it.
                            std::thread::spawn(move || {
                                let _ = reply.send(match crate::providers::list_models(kind, &base, &key) {
                                    Ok(models) => json!({"models": models}),
                                    Err(e) => json!({"error": e}),
                                });
                            });
                            continue;
                        }
                        None => json!({"error": "大腦不認得這個模型服務（兩邊 AnyBot 版本不同？）"}),
                    }
                }
                SyncKind::Edit(body) => {
                    if self.mir.on {
                        json!({"error": "這台 AnyBot 本身連著別的大腦"})
                    } else {
                        self.brain_edit(&body)
                    }
                }
            };
            let _ = r.reply.send(v);
        }
    }

    /// Keep the settings fingerprint fresh (at most once a second) so screens hear of edits.
    pub(super) fn brain_watch(&mut self) {
        if self.mir.on || !self.dirty || self.scr.cfg_at.map(|t| t.elapsed().as_millis() < 1000).unwrap_or(false) {
            return;
        }
        self.scr.cfg_at = Some(Instant::now());
        let mut c = config_json(&mut self.state);
        redact(&mut c);
        self.scr.cfg_hash = hash_value(&c);
    }

    fn brain_pull(&mut self, client: &str, since: u64) -> Value {
        if self.mir.on {
            return json!({"error": "這台 AnyBot 本身連著別的大腦"});
        }
        let version = remote::hub().version();
        // Forget screens not heard from in a day.
        self.scr.seen.retain(|_, s| s.at.map(|t| t.elapsed().as_secs() < 86_400).unwrap_or(false));
        let seen = self.scr.seen.entry(client.to_string()).or_default();
        // A screen that missed an answer (or is new) gets everything again.
        if seen.version != since || since == 0 {
            *seen = Seen::default();
        }
        seen.at = Some(Instant::now());
        seen.version = version;
        let acked = self.scr.acked.get(client).copied().unwrap_or(0);
        let mut out = json!({"version": version, "brain": self.state.remote.host_name, "edit_seq": acked});
        let mut c = config_json(&mut self.state);
        redact(&mut c);
        let ch = hash_value(&c);
        if seen.config != ch {
            seen.config = ch;
            out["config"] = c;
        }
        let mut bots = vec![];
        let mut threads = vec![];
        for b in &self.state.bots {
            let sigs: Vec<u64> = b.messages.iter().map(msg_sig).collect();
            let old = seen.bots.get(&b.id);
            let from = match old {
                Some(o) => o.iter().zip(sigs.iter()).position(|(a, b)| a != b).unwrap_or(o.len().min(sigs.len())),
                None => 0,
            };
            if old.map(|o| o.len() != sigs.len() || from < sigs.len()).unwrap_or(true) {
                bots.push(json!({"id": b.id, "from": from, "messages": &b.messages[from..]}));
            }
            seen.bots.insert(b.id, sigs);
            let ts = threads_sig(b);
            if seen.threads.get(&b.id) != Some(&ts) {
                seen.threads.insert(b.id, ts);
                threads.push(json!({"id": b.id, "threads": b.threads}));
            }
        }
        seen.bots.retain(|id, _| self.state.bots.iter().any(|b| b.id == *id));
        out["bots"] = Value::Array(bots);
        out["threads"] = Value::Array(threads);
        out["live"] = self.streams.iter().map(|(id, l)| (id.to_string(), json!({"status": l.status, "paused": l.paused}))).collect::<serde_json::Map<_, _>>().into();
        out["approvals"] = self
            .approvals
            .iter()
            .map(|(id, a)| {
                let kind = match a.kind {
                    ApprovalKind::Action => "action",
                    ApprovalKind::EnableTools => "tools",
                    ApprovalKind::EnableThisComputer => "local",
                };
                json!({"bot": id, "call_id": a.call_id, "tool": a.tool, "reason": a.reason, "grant": a.grant, "kind": kind})
            })
            .collect();
        // The bots' computer lives here; a screen shows its state, not its own computer's.
        let run = crate::cloudbox::run_state();
        out["box"] = json!({"label": run.label(), "running": run.is_running(), "available": crate::cloudbox::available(), "busy": crate::cloudbox::is_busy()});
        // Which computers each bot has (only the brain knows the account's other computers).
        out["computers"] = self
            .state
            .bots
            .iter()
            .map(|b| {
                let t = self.targets_for(b);
                let r = self.roles_for(b, &t);
                let (current, missing) = Self::chosen_computer(b, &t, &r);
                let names: Vec<Value> = t.iter().map(|x| json!({"name": x.name, "kind": computer_kind(x, &r)})).collect();
                (b.id.to_string(), json!({"names": names, "current": current, "missing": missing}))
            })
            .collect::<serde_json::Map<_, _>>()
            .into();
        out
    }

    /// A screen's edits.
    pub(super) fn brain_edit(&mut self, body: &Value) -> Value {
        let mut applied = 0;
        let total = body["ops"].as_array().map(|a| a.len()).unwrap_or(0);
        for op in body["ops"].as_array().into_iter().flatten() {
            let ok = match op["op"].as_str().unwrap_or("") {
                "set" => self.brain_set_top(op["key"].as_str().unwrap_or(""), op["value"].clone()),
                "bot_add" => {
                    let mut v = op["bot"].clone();
                    match serde_json::from_value::<Bot>(v.take()) {
                        Ok(mut b) => {
                            if b.id == 0 || self.state.bot(b.id).is_some() {
                                b.id = self.state.next_id.max(1);
                            }
                            self.state.next_id = self.state.next_id.max(b.id + 1);
                            self.state.bots.push(b);
                            self.state.fix_primary();
                            true
                        }
                        Err(_) => false,
                    }
                }
                "bot_del" => {
                    let id = op["id"].as_u64().unwrap_or(0);
                    if self.state.bot(id).is_none() {
                        false
                    } else {
                        self.stop(id);
                        self.state.bots.retain(|b| b.id != id);
                        self.state.fix_primary();
                        true
                    }
                }
                "merge" => self.brain_merge_top(op["key"].as_str().unwrap_or(""), &op["value"]),
                "patch" => {
                    let key = op["key"].as_str().unwrap_or("");
                    let mut v = self.top_value(key);
                    apply_patch(&mut v, &op["patch"]);
                    self.brain_set_top(key, v)
                }
                "bot_patch" => {
                    let (id, key) = (op["id"].as_u64().unwrap_or(0), op["key"].as_str().unwrap_or(""));
                    match self.state.bot(id).map(|b| serde_json::to_value(b).ok().map(|v| v[key].clone()).unwrap_or(Value::Null)) {
                        Some(mut v) => {
                            let old = v.clone();
                            apply_patch(&mut v, &op["patch"]);
                            unredact(&mut v, &old);
                            self.brain_set_bot(id, key, v)
                        }
                        None => false,
                    }
                }
                "bot_set" => self.brain_set_bot(op["id"].as_u64().unwrap_or(0), op["key"].as_str().unwrap_or(""), op["value"].clone()),
                "bot_read" => match self.state.bot_mut(op["id"].as_u64().unwrap_or(0)) {
                    Some(b) => {
                        b.unread = false;
                        true
                    }
                    None => false,
                },
                "bot_order" => {
                    let ids: Vec<u64> = op["ids"].as_array().into_iter().flatten().filter_map(Value::as_u64).collect();
                    self.state.bots.sort_by_key(|b| ids.iter().position(|i| *i == b.id).unwrap_or(usize::MAX));
                    true
                }
                _ => false,
            };
            if ok {
                applied += 1;
            }
        }
        if let (Some(client), Some(seq)) = (body["client"].as_str(), body["seq"].as_u64()) {
            self.scr.acked.insert(client.to_string(), seq);
            // Something was refused: send that screen the settings again, so it drops it.
            if applied < total {
                if let Some(s) = self.scr.seen.get_mut(client) {
                    s.config = 0;
                }
            }
        }
        if applied > 0 {
            self.mark();
            // Screens hear of it at once.
            self.scr.cfg_at = None;
            self.brain_watch();
        }
        json!({"ok": true, "applied": applied})
    }

    /// One top-level setting as JSON (with the brain's real keys).
    fn top_value(&mut self, key: &str) -> Value {
        let bots = std::mem::take(&mut self.state.bots);
        let v = serde_json::to_value(&self.state).map(|t| t[key].clone()).unwrap_or(Value::Null);
        self.state.bots = bots;
        v
    }

    fn brain_set_top(&mut self, key: &str, mut value: Value) -> bool {
        if key.is_empty() || key == "bots" || LOCAL_KEYS.contains(&key) {
            return false;
        }
        let bots = std::mem::take(&mut self.state.bots);
        let mut top = serde_json::to_value(&self.state).unwrap_or(Value::Null);
        unredact(&mut value, &top[key]);
        // Counters never go back (a screen may be behind).
        if key.starts_with("next_") {
            value = json!(value.as_u64().unwrap_or(0).max(top[key].as_u64().unwrap_or(0)));
        }
        top[key] = value;
        let ok = match serde_json::from_value::<State>(top) {
            Ok(mut st) => {
                st.remote = std::mem::take(&mut self.state.remote);
                self.state = st;
                true
            }
            Err(_) => false,
        };
        self.state.bots = bots;
        ok
    }

    /// 搬到大腦: add what the brain doesn't have yet (keys it lacks, skills and connectors by name).
    fn brain_merge_top(&mut self, key: &str, value: &Value) -> bool {
        let bots = std::mem::take(&mut self.state.bots);
        let top = serde_json::to_value(&self.state).unwrap_or(Value::Null);
        self.state.bots = bots;
        let mut cur = top[key].clone();
        match (key, &mut cur) {
            ("providers", Value::Object(o)) => {
                for (k, v) in value.as_object().into_iter().flatten() {
                    let missing = o.get(k).map(|x| x["api_key"].as_str().unwrap_or("").is_empty()).unwrap_or(true);
                    if missing && v["api_key"].as_str().map(|s| !s.is_empty() && s != REDACTED).unwrap_or(false) {
                        o.insert(k.clone(), v.clone());
                    }
                }
            }
            ("skills" | "mcp_servers", Value::Array(a)) => {
                for v in value.as_array().into_iter().flatten() {
                    if !a.iter().any(|x| x["name"] == v["name"]) {
                        a.push(v.clone());
                    }
                }
            }
            _ => return false,
        }
        self.brain_set_top(key, cur)
    }

    fn brain_set_bot(&mut self, id: u64, key: &str, value: Value) -> bool {
        if BOT_RUNTIME.contains(&key) {
            return false;
        }
        let Some(i) = self.state.bots.iter().position(|b| b.id == id) else { return false };
        let b = &mut self.state.bots[i];
        let msgs = std::mem::take(&mut b.messages);
        let threads = std::mem::take(&mut b.threads);
        let mut v = serde_json::to_value(&*b).unwrap_or(Value::Null);
        let mut value = value;
        if key == "routines" {
            keep_run_times(&mut value, &v["routines"]);
        }
        v[key] = value;
        let ok = match serde_json::from_value::<Bot>(v) {
            Ok(nb) => {
                *b = nb;
                true
            }
            Err(_) => false,
        };
        let b = &mut self.state.bots[i];
        b.messages = msgs;
        b.threads = threads;
        ok
    }

    // ---------- the screen ----------

    /// Once at start: a brain was chosen earlier, so show its copy.
    pub(super) fn mirror_boot(&mut self) {
        if self.mir.started || self.demo {
            return;
        }
        self.mir.started = true;
        self.mir.client = crate::httpd::random_hex(8);
        if !self.state.remote.brain_id.is_empty() && !self.state.remote.host_token.is_empty() {
            self.mirror_enter();
        }
    }

    /// Start showing the brain: this computer's own bots are kept aside, untouched.
    fn mirror_enter(&mut self) {
        let ids: Vec<u64> = self.streams.keys().copied().collect();
        for id in ids {
            self.stop(id);
        }
        self.approvals.clear();
        let local = self.state.clone();
        if let Some(copy) = std::fs::read_to_string(cache_path()).ok().and_then(|s| serde_json::from_str::<State>(&s).ok()).filter(|s| !s.bots.is_empty()) {
            self.state = copy;
            self.keep_local_fields(&local);
            // Edits wait for the brain's own answer; the copy may be old.
        }
        self.mir.base = Value::Null;
        self.mir.local = Some(local);
        self.mir.on = true;
        self.mir.online = false;
        self.mir.version.store(0, Ordering::SeqCst);
        self.mir.pending.lock().unwrap().clear();
        self.mir.reason.clear();
        self.mir.down_since = None;
        *self.mir.status.lock().unwrap() = "正在連到大腦…".into();
        self.mirror_worker();
        self.mirror_outbox();
        crate::tunnel::hello(&self.state.remote.brain_id, self.state.remote.device_link);
    }

    /// Back to this computer's own bots.
    fn mirror_leave(&mut self) {
        self.mir.gen.fetch_add(1, Ordering::SeqCst);
        self.mir.on = false;
        self.mir.online = false;
        self.mir.outbox = None;
        self.streams.clear();
        self.approvals.clear();
        if let Some(mut local) = self.mir.local.take() {
            let mut remote = self.state.remote.clone();
            remote.brain_id.clear();
            remote.brain_name.clear();
            remote.hands_for.clear();
            remote.hands_for_name.clear();
            local.remote = remote;
            local.theme = self.state.theme;
            local.accent = self.state.accent;
            if local.bot(local.selected).is_none() {
                local.selected = local.primary_bot;
            }
            self.state = local;
        } else {
            self.state.remote.brain_id.clear();
            self.state.remote.brain_name.clear();
            self.state.remote.hands_for.clear();
            self.state.remote.hands_for_name.clear();
        }
        self.state.save();
        self.dirty = false;
        crate::tunnel::hello("", self.state.remote.device_link);
    }

    fn keep_local_fields(&mut self, from: &State) {
        let st = &mut self.state;
        st.remote = from.remote.clone();
        st.theme = from.theme;
        st.accent = from.accent;
        st.sidebar_collapsed = from.sidebar_collapsed;
        st.sidebar_width = from.sidebar_width;
        st.machine_label = from.machine_label.clone();
        st.local_execution = from.local_execution;
        st.local_never = from.local_never;
        st.messages_send = from.messages_send;
        st.messages_no_ask = from.messages_no_ask;
        if st.bot(from.selected).is_some() {
            st.selected = from.selected;
        } else if st.bot(st.selected).is_none() {
            st.selected = st.primary_bot;
        }
    }

    fn mirror_worker(&mut self) {
        let gen = self.mir.gen.fetch_add(1, Ordering::SeqCst) + 1;
        let (tx, rx) = channel();
        self.mir.rx = Some(rx);
        self.mir.tx = Some(tx.clone());
        let (g, version, client, s, resync) = (self.mir.gen.clone(), self.mir.version.clone(), self.mir.client.clone(), self.state.remote.clone(), self.mir.resync.clone());
        let repaint = self.repaint_fn();
        std::thread::spawn(move || {
            let mut backoff = 1u64;
            while g.load(Ordering::SeqCst) == gen {
                let since = if resync.swap(false, Ordering::SeqCst) { 0 } else { version.load(Ordering::SeqCst) };
                match remote::sync_pull(&s, since, &client) {
                    Ok(v) => {
                        backoff = 1;
                        if g.load(Ordering::SeqCst) != gen {
                            break;
                        }
                        version.store(v["version"].as_u64().unwrap_or(0), Ordering::SeqCst);
                        let _ = tx.send(Incoming::Pull(v));
                    }
                    Err(e) => {
                        let _ = tx.send(Incoming::Offline(e));
                        // Start over (with everything) once it is back.
                        version.store(0, Ordering::SeqCst);
                        std::thread::sleep(std::time::Duration::from_secs(backoff));
                        backoff = (backoff * 2).min(20);
                    }
                }
                repaint();
            }
        });
    }

    fn repaint_fn(&self) -> Arc<dyn Fn() + Send + Sync> {
        match &self.ctx_handle {
            Some(c) => {
                let c = c.clone();
                Arc::new(move || c.request_repaint())
            }
            None => Arc::new(|| {}),
        }
    }

    /// Every frame on a screen: take in what the brain sent.
    pub(super) fn mirror_tick(&mut self) {
        if let Some((id, name)) = self.mir.want.take() {
            if self.mir.on {
                self.mirror_leave();
            }
            // This computer's hands are for that brain only.
            self.state.remote.hands_for = id.clone();
            self.state.remote.hands_for_name = name.clone();
            self.state.remote.brain_id = id;
            self.state.remote.brain_name = name;
            self.state.save();
            self.mirror_enter();
        }
        if std::mem::take(&mut self.mir.leave) && self.mir.on {
            self.mirror_leave();
        }
        if !self.mir.on {
            return;
        }
        let mut got = vec![];
        if let Some(rx) = &self.mir.rx {
            while let Ok(m) = rx.try_recv() {
                got.push(m);
            }
        }
        for m in got {
            match m {
                Incoming::Offline(e) => {
                    self.mir.online = false;
                    self.mir.base = Value::Null;
                    self.mir.down_since.get_or_insert_with(Instant::now);
                    *self.mir.status.lock().unwrap() = format!("連不到大腦：{e}");
                    self.mir.reason = e;
                }
                Incoming::File(path) => {
                    self.mir.fetching.remove(&path);
                    self.att.thumbs.remove(&path);
                }
                Incoming::Pull(v) => {
                    if let Some(e) = v["error"].as_str() {
                        self.mir.online = false;
                        self.mir.down_since.get_or_insert_with(Instant::now);
                        *self.mir.status.lock().unwrap() = e.to_string();
                        self.mir.reason = e.to_string();
                        continue;
                    }
                    self.mir.online = true;
                    self.mir.down_since = None;
                    self.mir.reason.clear();
                    *self.mir.status.lock().unwrap() = format!("已連到大腦「{}」", v["brain"].as_str().unwrap_or(&self.state.remote.brain_name));
                    self.mirror_apply(v);
                    if std::mem::take(&mut self.mir.move_after_join) {
                        self.mirror_move_local();
                    }
                }
            }
        }
    }

    fn mirror_apply(&mut self, v: Value) {
        // Edits the brain has taken in are no longer "on the way".
        let acked = v["edit_seq"].as_u64().unwrap_or(0);
        self.mir.pending.lock().unwrap().retain(|(s, _)| *s > acked);
        if v["config"].is_object() {
            // What the brain will have once the edits on the way arrive, and on top of that what
            // the person changed here and hasn't sent yet.
            let inflight: Vec<Value> = self.mir.pending.lock().unwrap().iter().flat_map(|(_, o)| o.clone()).collect();
            let unsaved = if self.mir.base.is_object() { diff_ops(&self.mir.base, &config_json(&mut self.state)) } else { vec![] };
            let mut base = v["config"].clone();
            apply_ops(&mut base, &inflight);
            let mut cfg = base.clone();
            apply_ops(&mut cfg, &unsaved);
            if !unsaved.is_empty() {
                self.dirty = true;
            }
            let local = std::mem::replace(&mut self.state, State::first_run());
            match serde_json::from_value::<State>(cfg.clone()) {
                Ok(mut st) => {
                    // Chats stay as they are (they come separately).
                    let mut old = local.bots.clone();
                    for b in st.bots.iter_mut() {
                        if let Some(o) = old.iter_mut().find(|o| o.id == b.id) {
                            b.messages = std::mem::take(&mut o.messages);
                            b.threads = std::mem::take(&mut o.threads);
                        }
                    }
                    self.state = st;
                    self.keep_local_fields(&local);
                    self.mir.base = base;
                }
                Err(e) => {
                    self.state = local;
                    *self.mir.error.lock().unwrap() = format!("大腦的設定讀不出來（兩邊 AnyBot 版本不同？）：{e}");
                }
            }
        }
        for d in v["bots"].as_array().into_iter().flatten() {
            let id = d["id"].as_u64().unwrap_or(0);
            let from = d["from"].as_u64().unwrap_or(0) as usize;
            let mut msgs: Vec<Message> = serde_json::from_value(d["messages"].clone()).unwrap_or_default();
            self.mirror_files(&mut msgs);
            if let Some(b) = self.state.bot_mut(id) {
                // The brain sends what changed from message `from` on, sure this copy has the
                // ones before. A copy that is shorter (cleared here, or an answer lost on the
                // way) would get them appended in the wrong place — the same message twice and
                // half-written replies piling up. Ask for the whole chat again instead.
                if b.messages.len() < from {
                    self.mir.resync.store(true, Ordering::SeqCst);
                    continue;
                }
                b.messages.truncate(from);
                b.messages.extend(msgs);
            }
        }
        for d in v["threads"].as_array().into_iter().flatten() {
            if let Some(b) = self.state.bot_mut(d["id"].as_u64().unwrap_or(0)) {
                b.threads = serde_json::from_value(d["threads"].clone()).unwrap_or_default();
            }
        }
        // Who is working, and what waits for the person.
        let live: HashMap<u64, (Option<String>, bool)> = v["live"].as_object().into_iter().flatten().filter_map(|(k, l)| Some((k.parse().ok()?, (l["status"].as_str().map(String::from), l["paused"].as_bool().unwrap_or(false))))).collect();
        self.streams.retain(|id, _| live.contains_key(id));
        for (id, (status, paused)) in live {
            let l = self.streams.entry(id).or_insert_with(|| Live {
                cancel: Arc::new(AtomicBool::new(false)),
                started: Instant::now(),
                last: Instant::now(),
                produced: true,
                status: None,
                paused: false,
                steer: Arc::default(),
                turn_id: String::new(),
                direct: Arc::default(),
            });
            l.status = status;
            l.paused = paused;
            l.last = Instant::now();
        }
        let mut waiting = HashMap::new();
        for a in v["approvals"].as_array().into_iter().flatten() {
            let id = a["bot"].as_u64().unwrap_or(0);
            let kind = match a["kind"].as_str().unwrap_or("") {
                "tools" => ApprovalKind::EnableTools,
                "local" => ApprovalKind::EnableThisComputer,
                _ => ApprovalKind::Action,
            };
            let (reply, _) = channel();
            let s = |k: &str| a[k].as_str().unwrap_or("").to_string();
            waiting.insert(id, Approval { call_id: s("call_id"), tool: s("tool"), reason: s("reason"), grant: s("grant"), reply, kind });
        }
        let ctx = self.ctx_handle.clone();
        for (id, a) in waiting {
            let new = self.approvals.get(&id).map(|o| o.call_id != a.call_id).unwrap_or(true);
            self.approvals.insert(id, a);
            if new {
                if let Some(c) = &ctx {
                    self.on_new_approval(c, id);
                }
            }
        }
        if v["box"].is_object() {
            self.mir.box_state = v["box"].clone();
        }
        if let Some(c) = v["computers"].as_object() {
            self.mir.computers = c.iter().filter_map(|(k, x)| Some((k.parse().ok()?, x.clone()))).collect();
        }
        let keep: Vec<u64> = v["approvals"].as_array().into_iter().flatten().filter_map(|a| a["bot"].as_u64()).collect();
        self.approvals.retain(|id, _| keep.contains(id));
        if self.state.bot(self.state.selected).is_none() {
            self.state.selected = self.state.primary_bot;
        }
        self.mirror_save_copy();
    }

    /// Files in the brain's chats live on the brain: show local copies, fetched once.
    fn mirror_files(&mut self, msgs: &mut [Message]) {
        for a in msgs.iter_mut().flat_map(|m| m.attachments.iter_mut()) {
            if std::path::Path::new(&a.path).exists() {
                continue;
            }
            let local = local_copy(&a.path, &a.name);
            let lp = local.display().to_string();
            let brain_path = std::mem::replace(&mut a.path, lp.clone());
            if local.exists() || !self.mir.fetching.insert(lp.clone()) {
                continue;
            }
            let (s, tx, repaint) = (self.state.remote.clone(), self.mir.tx.clone(), self.repaint_fn());
            std::thread::spawn(move || {
                if let Ok(bytes) = remote::sync_file(&s, &brain_path) {
                    let _ = std::fs::create_dir_all(local.parent().unwrap_or(std::path::Path::new(".")));
                    let tmp = local.with_extension("part");
                    if std::fs::write(&tmp, bytes).is_ok() {
                        let _ = std::fs::rename(&tmp, &local);
                    }
                }
                if let Some(tx) = tx {
                    let _ = tx.send(Incoming::File(lp));
                }
                repaint();
            });
        }
    }

    fn mirror_save_copy(&mut self) {
        if let Ok(s) = serde_json::to_string(&self.state) {
            let p = cache_path();
            let tmp = p.with_extension("tmp");
            if std::fs::write(&tmp, s).is_ok() {
                let _ = std::fs::rename(&tmp, &p);
            }
        }
    }

    /// Saving on a screen: edits go to the brain; this computer's own file keeps its own bots.
    pub(super) fn mirror_save(&mut self) {
        if let Some(local) = self.mir.local.as_mut() {
            local.remote = self.state.remote.clone();
            local.theme = self.state.theme;
            local.accent = self.state.accent;
            local.sidebar_collapsed = self.state.sidebar_collapsed;
            local.sidebar_width = self.state.sidebar_width;
            local.machine_label = self.state.machine_label.clone();
            local.local_execution = self.state.local_execution;
            local.local_never = self.state.local_never;
            local.messages_send = self.state.messages_send;
            local.messages_no_ask = self.state.messages_no_ask;
            local.save();
        }
        if !self.mir.online || !self.mir.base.is_object() {
            return;
        }
        let cur = config_json(&mut self.state);
        let ops = diff_ops(&self.mir.base, &cur);
        if ops.is_empty() {
            return;
        }
        self.mir.base = cur;
        self.mir.seq += 1;
        let seq = self.mir.seq;
        self.mir.pending.lock().unwrap().push((seq, ops.clone()));
        self.mirror_out(Out::Edit { seq, ops });
    }

    fn mirror_out(&mut self, o: Out) {
        if let Some(tx) = &self.mir.outbox {
            let _ = tx.send(o);
        }
    }

    /// One worker sends everything to the brain in order (a rename before the message that uses
    /// it, two quick edits in the order they were made).
    fn mirror_outbox(&mut self) {
        let (tx, rx) = channel::<Out>();
        self.mir.outbox = Some(tx);
        let (s, err, client, pending, resync) = (self.state.remote.clone(), self.mir.error.clone(), self.mir.client.clone(), self.mir.pending.clone(), self.mir.resync.clone());
        let (note, busy) = (self.mir.move_note.clone(), self.mir.moving.clone());
        let repaint = self.repaint_fn();
        std::thread::spawn(move || {
            for o in rx {
                match o {
                    Out::Edit { seq, ops } => {
                        if let Err(e) = remote::sync_post(&s, "edit", &json!({"ops": ops, "client": client, "seq": seq})) {
                            *err.lock().unwrap() = format!("剛才的改動沒有存到大腦：{e}");
                            pending.lock().unwrap().retain(|(n, _)| *n != seq);
                            resync.store(true, Ordering::SeqCst);
                        }
                    }
                    Out::Act(body) => {
                        if let Err(e) = remote::sync_post(&s, "act", &body) {
                            *err.lock().unwrap() = format!("大腦沒有收到：{e}");
                        }
                    }
                    Out::Send { bot, text, atts } => {
                        let mut paths = vec![];
                        for a in &atts {
                            match std::fs::read(&a.path).map_err(|e| format!("讀不到這個檔案（{e}）")).and_then(|b| remote::sync_upload(&s, bot, &a.name, &b)) {
                                Ok(p) => paths.push(p),
                                Err(e) => *err.lock().unwrap() = format!("「{}」沒有傳到大腦：{e}", a.name),
                            }
                        }
                        if let Err(e) = remote::sync_post(&s, "act", &json!({"bot": bot, "action": "send", "text": text, "attachments": paths})) {
                            *err.lock().unwrap() = format!("訊息沒有送到大腦：{e}");
                            // Take back the message shown ahead of time.
                            resync.store(true, Ordering::SeqCst);
                        }
                    }
                    Out::Move { ops, n } => {
                        *note.lock().unwrap() = match remote::sync_post(&s, "edit", &json!({"ops": ops})) {
                            Ok(_) if n == 0 => "已同步：大腦上已經有這台的 Bot；模型金鑰、技能和連接器有缺的已補上".into(),
                            Ok(_) => format!("已把 {n} 個 Bot（連同聊天）搬到大腦"),
                            Err(e) => format!("搬移失敗：{e}"),
                        };
                        busy.store(false, Ordering::SeqCst);
                    }
                }
                repaint();
            }
        });
    }

    /// A chat action on a screen goes to the brain.
    pub(super) fn mirror_act(&mut self, body: Value) {
        if !self.mir.online {
            *self.mir.error.lock().unwrap() = "連不到大腦，現在只能看。".into();
            return;
        }
        self.mirror_out(Out::Act(body));
    }

    /// Send a message through the brain: files go up first, then the text.
    pub(super) fn mirror_send(&mut self, bot: u64, text: String, atts: Vec<crate::attach::Attachment>) -> bool {
        if !self.mir.online {
            *self.mir.error.lock().unwrap() = "連不到大腦，訊息沒有送出。".into();
            return false;
        }
        // Shown at once; the brain's copy replaces it.
        if !self.streams.contains_key(&bot) {
            if let Some(b) = self.state.bot_mut(bot) {
                b.messages.push(Message { attachments: atts.clone(), ..Message::user(&text) });
            }
        }
        // Settings changed just before go first.
        if self.dirty {
            self.mirror_save();
        }
        self.mirror_out(Out::Send { bot, text, atts });
        true
    }

    /// 把這台的 Bot 搬到大腦: copy this computer's own bots (with their chats), keys, skills and
    /// connectors to the brain, as new bots there.
    pub(super) fn mirror_move_local(&mut self) {
        let Some(local) = self.mir.local.clone() else { return };
        if self.mir.moving.swap(true, Ordering::SeqCst) {
            return;
        }
        let mut ops: Vec<Value> = vec![];
        // Skip what the brain already has: the same starter bot never used here, or a bot moved
        // before (same name, same chat).
        let last = |b: &Bot| b.messages.last().map(|m| (m.at, m.text.clone()));
        let moving: Vec<&Bot> = local
            .bots
            .iter()
            .filter(|b| !self.state.bots.iter().any(|o| o.name == b.name && (b.messages.is_empty() || (o.messages.len() == b.messages.len() && last(o) == last(b)))))
            .collect();
        for b in moving.iter().copied() {
            let mut v = serde_json::to_value(b).unwrap_or(Value::Null);
            v["id"] = json!(0);
            ops.push(json!({"op": "bot_add", "bot": v}));
        }
        let top = serde_json::to_value(&local).unwrap_or(Value::Null);
        for k in ["providers", "skills", "mcp_servers"] {
            ops.push(json!({"op": "merge", "key": k, "value": top[k]}));
        }
        let n = moving.len();
        *self.mir.move_note.lock().unwrap() = "搬移中…".into();
        self.mirror_out(Out::Move { ops, n });
    }

    /// The bar above the chat while showing a brain.
    pub(super) fn mirror_banner(&mut self, ui: &mut egui::Ui) {
        if !self.mir.on {
            return;
        }
        let p = self.pal;
        let err = std::mem::take(&mut *self.mir.error.lock().unwrap());
        if !err.is_empty() {
            self.notice = Some(err);
        }
        if self.mir.online {
            return;
        }
        // A blip (the account server restarting) isn't worth a warning.
        let connecting = self.mir.down_since.is_none();
        let (title, reason, tail) = match self.mir.down_since {
            None => (format!("正在連到大腦「{}」…", self.state.remote.brain_name), String::new(), String::new()),
            Some(t) if t.elapsed().as_secs() < 4 => return,
            Some(_) => (format!("連不到大腦「{}」", self.state.remote.brain_name), self.mir.reason.clone(), t("之前的對話還能看，但現在不能傳訊息。連回來後會自動恢復。")),
        };
        ui.ctx().request_repaint_after(std::time::Duration::from_secs(1));
        ui.vertical_centered(|ui| {
            ui.set_max_width(TRANSCRIPT_MAX_WIDTH.min(ui.available_width() - 48.0));
            Frame::new().fill(if connecting { p.hover } else { p.danger.gamma_multiply(0.08) }).corner_radius(8).inner_margin(Margin::symmetric(12, 8)).show(ui, |ui| {
                ui.vertical(|ui| {
                    ui.label(RichText::new(title).size(FONT_SM).strong().color(p.text));
                    for line in [reason, tail] {
                        if !line.is_empty() {
                            ui.add(egui::Label::new(RichText::new(line).size(FONT_SM).color(p.text2)).wrap());
                        }
                    }
                });
            });
        });
        ui.add_space(6.0);
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn edits_become_small_operations() {
        let base = json!({"theme": "light", "folders": ["a"], "bots": [{"id": 1, "name": "A", "unread": true}, {"id": 2, "name": "B"}]});
        let cur = json!({"theme": "dark", "folders": ["a", "b"], "bots": [{"id": 1, "name": "A2", "unread": false}, {"id": 3, "name": "C"}]});
        let ops = diff_ops(&base, &cur);
        // theme is this computer's own; folders changed.
        assert!(ops.iter().any(|o| o["op"] == "patch" && o["key"] == "folders" && o["patch"]["list"]["put"] == json!(["b"])));
        assert!(!ops.iter().any(|o| o["key"] == "theme"));
        assert!(ops.iter().any(|o| o["op"] == "bot_set" && o["key"] == "name" && o["value"] == "A2"));
        assert!(ops.iter().any(|o| o["op"] == "bot_read" && o["id"] == 1));
        assert!(ops.iter().any(|o| o["op"] == "bot_add" && o["bot"]["id"] == 3));
        assert!(ops.iter().any(|o| o["op"] == "bot_del" && o["id"] == 2));
    }

    #[test]
    fn keys_stay_on_the_brain() {
        let mut v = json!({"remote": {"host_token": "x"}, "providers": {"xai": {"api_key": "sk-1"}, "openai": {"api_key": ""}}, "channels": [{"id": 4, "token": "t"}]});
        let old = v.clone();
        redact(&mut v);
        assert!(v.get("remote").is_none());
        assert_eq!(v["providers"]["xai"]["api_key"], REDACTED);
        assert_eq!(v["providers"]["openai"]["api_key"], "");
        assert_eq!(v["channels"][0]["token"], REDACTED);
        // An edit that kept the stand-in keeps the real key.
        let mut edit = v["providers"].clone();
        edit["openai"]["api_key"] = json!("sk-new");
        unredact(&mut edit, &old["providers"]);
        assert_eq!(edit["xai"]["api_key"], "sk-1");
        assert_eq!(edit["openai"]["api_key"], "sk-new");
        let mut ch = v["channels"].clone();
        unredact(&mut ch, &old["channels"]);
        assert_eq!(ch[0]["token"], "t");
    }

    #[test]
    fn edits_replay_on_a_newer_copy() {
        let base = json!({"folders": ["a"], "bots": [{"id": 1, "name": "A", "unread": true}, {"id": 2, "name": "B"}]});
        let cur = json!({"folders": ["a", "b"], "bots": [{"id": 2, "name": "B"}, {"id": 1, "name": "A2", "unread": false}, {"id": 3, "name": "C"}]});
        let ops = diff_ops(&base, &cur);
        let mut again = base.clone();
        apply_ops(&mut again, &ops);
        assert_eq!(again, cur);
        // The brain meanwhile renamed bot 2: the screen's own edit stays, the brain's shows too.
        let mut newer = json!({"folders": ["a"], "bots": [{"id": 1, "name": "A", "unread": true}, {"id": 2, "name": "B from brain"}]});
        apply_ops(&mut newer, &ops);
        assert_eq!(newer["bots"][1]["name"], "A2");
        assert_eq!(newer["bots"][0]["name"], "B from brain");
        assert_eq!(newer["folders"], json!(["a", "b"]));
    }

    #[test]
    fn an_old_copy_cant_make_a_routine_run_twice() {
        let brain = json!([{"id": 7, "schedule": "daily", "trigger": null, "paused": false, "last_run": 200, "next_run": 300}]);
        let mut edit = json!([{"id": 7, "title": "new", "schedule": "daily", "trigger": null, "paused": false, "last_run": 100, "next_run": 150}]);
        keep_run_times(&mut edit, &brain);
        assert_eq!(edit[0]["last_run"], 200);
        assert_eq!(edit[0]["next_run"], 300);
        assert_eq!(edit[0]["title"], "new");
        // A new schedule gets worked out again.
        let mut moved = json!([{"id": 7, "schedule": "weekly", "trigger": null, "paused": false, "last_run": 100, "next_run": null}]);
        keep_run_times(&mut moved, &brain);
        assert_eq!(moved[0]["last_run"], 200);
        assert!(moved[0]["next_run"].is_null());
    }

    #[test]
    fn failures_read_as_words_not_codes() {
        let w = remote::why_refused(502, &Value::Null, "大腦");
        assert!(!w.contains("502") && w.contains("帳號伺服器"));
        let off = remote::why_refused(503, &json!({"error": "那台 AnyBot 目前離線（電腦關機、睡眠，或 AnyBot 沒開）"}), "大腦");
        assert!(off.starts_with("大腦目前離線"));
        assert!(remote::why_refused(401, &Value::Null, "大腦").contains("重新登入"));
        assert!(remote::why_unreachable(&ureq::Error::HostNotFound).contains("網路"));
    }

    #[test]
    fn two_computers_edit_one_list_without_undoing_each_other() {
        let base = json!({"skills": [{"name": "a", "on": true}, {"name": "b", "on": true}], "providers": {"xai": {"model": "1"}, "openai": {"model": "1"}}, "bots": [{"id": 1, "memories": ["x", "y"]}]});
        // Laptop turns skill a off, changes xai, forgets memory x.
        let mut laptop = base.clone();
        laptop["skills"][0]["on"] = json!(false);
        laptop["providers"]["xai"]["model"] = json!("2");
        laptop["bots"][0]["memories"] = json!(["y"]);
        // Meanwhile the desk computer turned skill b off, changed openai, and the bot learned z.
        let mut brain = base.clone();
        brain["skills"][1]["on"] = json!(false);
        brain["skills"].as_array_mut().unwrap().push(json!({"name": "c", "on": true}));
        brain["providers"]["openai"]["model"] = json!("3");
        brain["bots"][0]["memories"] = json!(["x", "y", "z"]);
        let ops = diff_ops(&base, &laptop);
        assert!(ops.iter().all(|o| o["op"] != "set" || o["key"] != "skills"), "{ops:?}");
        apply_ops(&mut brain, &ops);
        assert_eq!(brain["skills"], json!([{"name": "a", "on": false}, {"name": "b", "on": false}, {"name": "c", "on": true}]));
        assert_eq!(brain["providers"], json!({"xai": {"model": "2"}, "openai": {"model": "3"}}));
        assert_eq!(brain["bots"][0]["memories"], json!(["y", "z"]));
    }

    #[test]
    fn lists_without_names_are_sent_whole() {
        let p = patch_of(&json!([[1], [2]]), &json!([[2]]));
        assert_eq!(p, json!({"value": [[2]]}));
        let mut cur = json!([{"id": 1}, {"id": 2}]);
        apply_patch(&mut cur, &patch_of(&json!([{"id": 1}, {"id": 2}]), &json!([{"id": 2}, {"id": 1}])));
        assert_eq!(cur, json!([{"id": 2}, {"id": 1}]));
    }
}