// `anybot setup`: a guided setup in the terminal, for computers set up over SSH or without a
// window (a server, a Linux box). Five short steps: what this computer is (大腦 or 手腳), its
// name, the account server, the account, and — for hands — which brain may use it, picked from
// the account's AnyBots as they are right now. Then it saves the settings, makes AnyBot start with
// the computer (systemd), and waits until the account server and the brain see it.
//
// Without a terminal (a script), the same can be given as flags:
//   anybot setup --role hands --name 書房電腦 --server https://anybot.example.com --user me
//                --brain 雲端大腦 [--create] [--invite 碼] [--no-service]
// with the password in ANYBOT_ACCOUNT_PASSWORD (or on stdin with --password-stdin).

use crate::model::State;
use crate::remote::{self, Settings};
use crossterm::event::{self, Event, KeyCode, KeyEventKind, KeyModifiers};
use crossterm::style::{Attribute, Color, Print, ResetColor, SetAttribute, SetForegroundColor};
use crossterm::{cursor, execute, queue, terminal};
use std::io::{IsTerminal, Write};
use std::sync::mpsc::{channel, Receiver, Sender};
use std::time::{Duration, Instant};
use unicode_width::{UnicodeWidthChar, UnicodeWidthStr};

const ACC: Color = Color::Cyan;
const GOOD: Color = Color::Green;
const WARN: Color = Color::Yellow;
const BAD: Color = Color::Red;
const DIM: Color = Color::DarkGrey;
const SPIN: [&str; 10] = ["⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"];
const UNIT: &str = "anybot.service";

#[derive(Clone, Copy, PartialEq, Debug)]
enum Role {
    Hands,
    Brain,
}

#[derive(Clone, Copy, PartialEq, Debug)]
enum Step {
    Role,
    Name,
    Server,
    Account,
    Brain,
    Confirm,
    Install,
    Done,
}

#[derive(Clone, Debug)]
struct Peer {
    id: String,
    name: String,
    online: bool,
    last: String,
}

#[derive(Clone, Copy, PartialEq, Debug)]
enum Mark {
    Wait,
    Run,
    Ok,
    Warn,
    Fail,
}

enum Msg {
    Server(Result<String, String>),
    Joined(Result<Settings, String>),
    Peers(Result<Vec<Peer>, String>),
    Progress(usize, Mark, String),
    Finished(Vec<String>),
}

/// What this computer has.
#[derive(Clone)]
struct Env {
    linux: bool,
    display: String,
    systemd: bool,
    xvfb: bool,
}

impl Env {
    fn detect() -> Env {
        let var = |k: &str| std::env::var(k).ok().filter(|v| !v.is_empty());
        // "wayland" when only Wayland is there (nothing to remember for a service).
        let linux = cfg!(target_os = "linux");
        // A Mac or Windows PC always has its screen.
        let display = if !linux { "desktop".to_string() } else { var("DISPLAY").or_else(|| var("WAYLAND_DISPLAY").map(|_| "wayland".to_string())).unwrap_or_default() };
        let systemd = linux
            && std::process::Command::new("systemctl")
                .args(["--user", "is-system-running"])
                .output()
                .map(|o| {
                    let out = String::from_utf8_lossy(&o.stdout);
                    !out.trim().is_empty() && !out.contains("offline")
                })
                .unwrap_or(false);
        Env { linux, display, systemd, xvfb: which("xvfb-run") }
    }
    fn has_display(&self) -> bool {
        !self.display.is_empty()
    }
    fn summary(&self) -> String {
        let os = if self.linux {
            "Linux"
        } else if cfg!(target_os = "macos") {
            "macOS"
        } else {
            "Windows"
        };
        let screen = if self.has_display() {
            "有螢幕"
        } else if self.xvfb {
            "沒有螢幕（會開一個虛擬螢幕）"
        } else {
            "沒有螢幕"
        };
        let service = if self.systemd { "會設成開機自動執行" } else { "沒有 systemd（要自己啟動）" };
        format!("這台：{os} · {screen} · {service}")
    }
}

fn which(cmd: &str) -> bool {
    std::env::var_os("PATH").map(|p| std::env::split_paths(&p).any(|d| d.join(cmd).is_file())).unwrap_or(false)
}

// ---------- drawing ----------

#[derive(Clone, Copy, Default)]
struct Sty {
    fg: Option<Color>,
    bold: bool,
}

type Span = (String, Sty);
type Line = Vec<Span>;

fn sp(s: impl Into<String>, fg: Option<Color>, bold: bool) -> Span {
    (s.into(), Sty { fg, bold })
}
fn plain(s: impl Into<String>) -> Span {
    sp(s, None, false)
}
fn dim(s: impl Into<String>) -> Span {
    sp(s, Some(DIM), false)
}
fn strong(s: impl Into<String>) -> Span {
    sp(s, None, true)
}
fn colored(s: impl Into<String>, c: Color) -> Span {
    sp(s, Some(c), false)
}

fn width(l: &Line) -> usize {
    l.iter().map(|(s, _)| s.width()).sum()
}

/// Break text to lines at most `w` wide (anywhere: Chinese has no spaces).
fn wrap(text: &str, w: usize) -> Vec<String> {
    let mut out = vec![];
    for para in text.split('\n') {
        let mut cur = String::new();
        let mut cw = 0;
        for ch in para.chars() {
            let c = ch.width().unwrap_or(0);
            if cw + c > w && !cur.is_empty() {
                // A line never starts with closing punctuation: take the last character along.
                let closing = |c: char| "。，、；：」）！？』,.;:!?)".contains(c);
                let mut carry = String::new();
                if closing(ch) {
                    while let Some(p) = cur.pop() {
                        carry.insert(0, p);
                        if !closing(p) || cur.is_empty() {
                            break;
                        }
                    }
                }
                out.push(std::mem::take(&mut cur));
                cw = carry.width();
                cur = carry;
            }
            cur.push(ch);
            cw += c;
        }
        out.push(cur);
    }
    out
}

fn para(text: &str, indent: usize, w: usize, f: fn(String) -> Span) -> Vec<Line> {
    wrap(text, w.saturating_sub(indent).max(10)).into_iter().map(|t| vec![plain(" ".repeat(indent)), f(t)]).collect()
}

/// Cut a line to `w` columns.
fn clip(l: Line, w: usize) -> Line {
    let mut out = vec![];
    let mut used = 0;
    for (s, st) in l {
        let mut keep = String::new();
        for ch in s.chars() {
            let c = ch.width().unwrap_or(0);
            if used + c > w {
                break;
            }
            keep.push(ch);
            used += c;
        }
        out.push((keep, st));
        if used >= w {
            break;
        }
    }
    out
}

// ---------- the setup ----------

struct Wiz {
    env: Env,
    step: Step,
    role: Role,
    sel: usize,
    name: String,
    url: String,
    user: String,
    pass: String,
    invite: String,
    create: bool,
    focus: usize,
    server: String,
    joined: Option<Settings>,
    peers: Vec<Peer>,
    brain: Option<Peer>,
    busy: Option<String>,
    rx: Option<Receiver<Msg>>,
    tx: Sender<Msg>,
    spin: usize,
    error: String,
    progress: Vec<(String, Mark, String)>,
    tips: Vec<String>,
    ok: bool,
    quit: bool,
    service: bool,
    saved: Settings,
}

impl Wiz {
    fn new() -> Wiz {
        let st = State::load();
        let saved = st.remote.clone();
        let (tx, rx) = channel();
        let env = Env::detect();
        Wiz {
            role: if saved.device_link || !env.has_display() { Role::Hands } else { Role::Brain },
            sel: if saved.device_link || !env.has_display() { 0 } else { 1 },
            step: Step::Role,
            name: if saved.host_name.is_empty() { remote::default_host_name() } else { saved.host_name.clone() },
            url: saved.relay_url.clone(),
            user: saved.relay_user.clone(),
            pass: String::new(),
            invite: String::new(),
            create: false,
            focus: if saved.relay_user.is_empty() { 0 } else { 1 },
            server: String::new(),
            joined: None,
            peers: vec![],
            brain: None,
            busy: None,
            rx: Some(rx),
            tx,
            spin: 0,
            error: String::new(),
            progress: vec![],
            tips: vec![],
            ok: false,
            quit: false,
            service: env.systemd,
            saved,
            env,
        }
    }

    fn crumbs(&self) -> Vec<&'static str> {
        let role = if self.step == Step::Role { if self.sel == 0 { Role::Hands } else { Role::Brain } } else { self.role };
        match role {
            Role::Hands => vec!["角色", "名字", "帳號", "大腦", "完成"],
            Role::Brain => vec!["角色", "名字", "帳號", "完成"],
        }
    }

    fn crumb_at(&self) -> usize {
        let last = self.crumbs().len() - 1;
        match self.step {
            Step::Role => 0,
            Step::Name => 1,
            Step::Server | Step::Account => 2,
            Step::Brain => 3,
            Step::Confirm | Step::Install | Step::Done => last,
        }
    }

    // ----- what each step shows -----

    fn title(&self) -> (&'static str, String) {
        match self.step {
            Step::Role => ("這台電腦要做什麼？", "之後隨時可以再執行 anybot setup 改。".into()),
            Step::Name => ("這台電腦叫什麼？", "手機、大腦和其他電腦上看到的名字。".into()),
            Step::Server => ("帳號伺服器在哪裡？", "就是手機登入 AnyBot 的那個網址，例如 https://anybot.example.com".into()),
            Step::Account => ("登入帳號", "和手機、大腦用同一個帳號。密碼只用來登入，不會存在這台電腦上。".into()),
            Step::Brain => ("要當哪個大腦的手腳？", "只有選的大腦能使用這台電腦；它的 Bot 每個動作仍照大腦的規則先問你。".into()),
            Step::Confirm => ("確認一下", "按 Enter 開始設定。".into()),
            Step::Install => (if self.ok { "設定好了" } else { "正在設定…" }, String::new()),
            Step::Done => (if self.ok { "設定好了" } else { "沒有完成" }, String::new()),
        }
    }

    fn field(&self, label: &str, value: &str, focused: bool, secret: bool, hint: &str) -> Line {
        let shown = if secret { "●".repeat(value.chars().count()) } else { value.to_string() };
        let mut l = vec![if focused { colored("❯ ", ACC) } else { plain("  ") }, sp(format!("{label}{}", " ".repeat(8usize.saturating_sub(label.width()))), Some(if focused { ACC } else { DIM }), focused)];
        if shown.is_empty() && !focused {
            l.push(dim(hint));
        } else {
            l.push(strong(shown));
            if focused {
                l.push(colored("▌", ACC));
                if value.is_empty() && !hint.is_empty() {
                    l.push(dim(format!(" {hint}")));
                }
            }
        }
        l
    }

    fn body(&self, w: usize) -> Vec<Line> {
        let mut b: Vec<Line> = vec![];
        match self.step {
            Step::Role => {
                let opts = [
                    ("手腳", "讓大腦的 Bot 使用這台電腦：看畫面、點擊打字、檔案和指令、這台的瀏覽器。"),
                    ("大腦", "這台保存所有 Bot、聊天、記憶和排程，一直開著；其他電腦和手機都連到它。"),
                ];
                for (i, (name, desc)) in opts.iter().enumerate() {
                    let on = self.sel == i;
                    b.push(vec![if on { colored("❯ ", ACC) } else { plain("  ") }, sp(if on { "● " } else { "○ " }, Some(if on { ACC } else { DIM }), false), sp(*name, if on { Some(ACC) } else { None }, true)]);
                    b.extend(para(desc, 6, w, dim));
                    b.push(vec![]);
                }
                b.push(vec![dim(self.env.summary())]);
            }
            Step::Name => b.push(self.field("名字", &self.name, true, false, "")),
            Step::Server => b.push(self.field("網址", &self.url, true, false, "https://…")),
            Step::Account => {
                let reuse = self.can_reuse();
                b.push(self.field("帳號", &self.user, self.focus == 0, false, "帳號名稱"));
                b.push(self.field("密碼", &self.pass, self.focus == 1, true, if reuse { "已登入過，留空直接沿用" } else { "" }));
                b.push(vec![
                    if self.focus == 2 { colored("❯ ", ACC) } else { plain("  ") },
                    sp(if self.create { "■ " } else { "□ " }, Some(if self.focus == 2 { ACC } else { DIM }), false),
                    sp("這是新帳號（第一次用這台伺服器）", if self.focus == 2 { Some(ACC) } else { None }, false),
                    dim(if self.focus == 2 { "  空白鍵切換" } else { "" }),
                ]);
                if self.create {
                    b.push(self.field("邀請碼", &self.invite, self.focus == 3, false, "伺服器管理員給的（第一個帳號不用）"));
                }
            }
            Step::Brain => {
                if self.peers.is_empty() && self.busy.is_none() {
                    b.extend(para("帳號裡還沒有其他 AnyBot。先把大腦裝好（伺服器上執行 deploy/server/setup.sh，或在一台電腦上開 AnyBot 登入帳號），再按 r 重新整理。", 0, w, plain));
                    b.push(vec![]);
                }
                for (i, p) in self.peers.iter().enumerate() {
                    let on = self.sel == i;
                    let status = if p.online { colored("在線上", GOOD) } else { dim(format!("離線（{}）", p.last)) };
                    let name = format!("{}  ", p.name);
                    let pad = 28usize.saturating_sub(name.width());
                    b.push(vec![if on { colored("❯ ", ACC) } else { plain("  ") }, sp(if p.online { "● " } else { "○ " }, Some(if p.online { GOOD } else { DIM }), false), sp(name, if on { Some(ACC) } else { None }, true), plain(" ".repeat(pad)), status]);
                }
                let i = self.peers.len();
                let on = self.sel == i;
                if !self.peers.is_empty() {
                    b.push(vec![]);
                }
                b.push(vec![if on { colored("❯ ", ACC) } else { plain("  ") }, sp("○ ", Some(DIM), false), sp("不指定", if on { Some(ACC) } else { None }, true)]);
                b.extend(para("帳號裡任何一台 AnyBot 都能使用這台電腦。", 6, w, dim));
            }
            Step::Confirm => {
                let row = |k: &str, v: String| vec![dim(format!("{k}{}", " ".repeat(14usize.saturating_sub(k.width())))), strong(v)];
                b.push(row("這台是", match self.role { Role::Hands => "手腳".into(), Role::Brain => "大腦".into() }));
                b.push(row("名字", self.name.clone()));
                b.push(row("帳號伺服器", self.server.clone()));
                b.push(row("帳號", self.user.clone()));
                if self.role == Role::Hands {
                    b.push(row("給哪個大腦用", self.brain.as_ref().map(|p| p.name.clone()).unwrap_or_else(|| "不指定（帳號裡任何一台）".into())));
                    let screen = if self.env.has_display() {
                        "用這台的螢幕".to_string()
                    } else if self.env.xvfb {
                        "開一個 1440×900 的虛擬螢幕".to_string()
                    } else {
                        "沒有螢幕：只能用檔案和指令".to_string()
                    };
                    b.push(row("螢幕", screen));
                }
                b.push(row("開機自動執行", if self.service { "會（systemd 使用者服務 anybot）".into() } else if self.env.linux { "不會（這台沒有 systemd）".into() } else { "不會（請開 AnyBot App）".into() }));
                if self.role == Role::Hands && !self.env.has_display() && !self.env.xvfb && self.env.linux {
                    b.push(vec![]);
                    b.extend(para("想讓 Bot 看這台的畫面、操作程式：先執行 ./deploy/linux/hands.sh --deps 裝好虛擬螢幕，再回來。", 0, w, |s| colored(s, WARN)));
                }
            }
            Step::Install | Step::Done => {
                for (label, mark, note) in &self.progress {
                    let icon = match mark {
                        Mark::Wait => dim("·"),
                        Mark::Run => colored(SPIN[self.spin % SPIN.len()], ACC),
                        Mark::Ok => colored("✓", GOOD),
                        Mark::Warn => colored("!", WARN),
                        Mark::Fail => colored("✗", BAD),
                    };
                    b.push(vec![icon, plain(" "), sp(label.clone(), if *mark == Mark::Wait { Some(DIM) } else { None }, *mark == Mark::Run)]);
                    if !note.is_empty() {
                        let c = match mark {
                            Mark::Fail => BAD,
                            Mark::Warn => WARN,
                            _ => DIM,
                        };
                        b.extend(para(note, 2, w, if c == BAD { |s| colored(s, BAD) } else if c == WARN { |s| colored(s, WARN) } else { dim }));
                    }
                }
                if !self.tips.is_empty() {
                    b.push(vec![]);
                    for t in &self.tips {
                        if let Some((k, v)) = t.split_once('\t') {
                            b.push(vec![dim(format!("{k}{}", " ".repeat(10usize.saturating_sub(k.width())))), colored(v.to_string(), ACC)]);
                        } else {
                            b.extend(para(t, 0, w, plain));
                        }
                    }
                }
            }
        }
        if let Some(what) = &self.busy {
            b.push(vec![]);
            b.push(vec![colored(SPIN[self.spin % SPIN.len()], ACC), plain(" "), colored(what.clone(), ACC)]);
        }
        if !self.error.is_empty() {
            b.push(vec![]);
            for l in wrap(&self.error, w.saturating_sub(2)) {
                b.push(vec![colored(if b.last().map(|x| x.is_empty()).unwrap_or(true) { "✗ " } else { "  " }, BAD), colored(l, BAD)]);
            }
        }
        b
    }

    fn keys(&self) -> &'static str {
        if self.busy.is_some() {
            return "Ctrl+C 離開";
        }
        match self.step {
            Step::Brain => "↑↓ 選擇   Enter 確定   r 重新整理   Esc 上一步",
            Step::Role => "↑↓ 選擇   Enter 下一步   Esc 離開",
            Step::Account => "↑↓ 換欄位   Enter 登入   Esc 上一步",
            Step::Confirm => "Enter 開始設定   Esc 上一步",
            Step::Install => "Ctrl+C 離開",
            Step::Done => "Enter 離開",
            _ => "Enter 下一步   Esc 上一步",
        }
    }

    fn render(&self, out: &mut impl Write) -> std::io::Result<()> {
        let (cols, rows) = terminal::size().unwrap_or((80, 24));
        let cols = cols as usize;
        let w = cols.saturating_sub(4).clamp(36, 78);
        let inner = w - 4;
        let mut lines: Vec<Line> = vec![vec![]];
        // Header: the name, and where we are.
        let mut head = vec![plain("  "), colored("◆ ", ACC), strong("AnyBot 設定")];
        let at = self.crumb_at();
        let mut crumbs: Line = vec![plain("  ")];
        for (i, c) in self.crumbs().iter().enumerate() {
            if i > 0 {
                crumbs.push(dim(" ─ "));
            }
            let done = i < at || (self.step == Step::Done && self.ok);
            crumbs.push(if done {
                colored(format!("✓ {c}"), GOOD)
            } else if i == at {
                sp(format!("{} {c}", i + 1), Some(ACC), true)
            } else {
                dim(format!("{} {c}", i + 1))
            });
        }
        if width(&head) + width(&crumbs) + 4 <= w + 2 {
            let gap = (w + 2).saturating_sub(width(&head) + width(&crumbs));
            head.push(plain(" ".repeat(gap)));
            head.extend(crumbs.into_iter().skip(1));
            lines.push(head);
        } else {
            lines.push(head);
            lines.push(crumbs);
        }
        lines.push(vec![]);
        // The card.
        let (title, sub) = self.title();
        let mut card: Vec<Line> = vec![vec![], vec![strong(title)]];
        if !sub.is_empty() {
            card.extend(para(&sub, 0, inner, dim));
        }
        card.push(vec![]);
        card.extend(self.body(inner));
        card.push(vec![]);
        let edge = |l: &str, r: &str| vec![plain("  "), dim(format!("{l}{}{r}", "─".repeat(w - 2)))];
        lines.push(edge("╭", "╮"));
        for l in card {
            let l = clip(l, inner);
            let pad = inner.saturating_sub(width(&l));
            let mut row = vec![plain("  "), dim("│ ")];
            row.extend(l);
            row.push(plain(" ".repeat(pad)));
            row.push(dim(" │"));
            lines.push(row);
        }
        lines.push(edge("╰", "╯"));
        lines.push(vec![plain("   "), dim(self.keys())]);

        queue!(out, terminal::BeginSynchronizedUpdate, terminal::Clear(terminal::ClearType::All))?;
        for (y, l) in lines.into_iter().enumerate().take(rows as usize) {
            queue!(out, cursor::MoveTo(0, y as u16))?;
            for (s, st) in clip(l, cols) {
                if let Some(c) = st.fg {
                    queue!(out, SetForegroundColor(c))?;
                }
                if st.bold {
                    queue!(out, SetAttribute(Attribute::Bold))?;
                }
                queue!(out, Print(s), SetAttribute(Attribute::Reset), ResetColor)?;
            }
        }
        queue!(out, terminal::EndSynchronizedUpdate)?;
        out.flush()
    }

    // ----- moving through the steps -----

    fn can_reuse(&self) -> bool {
        let s = &self.saved;
        !s.host_token.is_empty() && s.relay_url == self.server && s.relay_user == self.user.trim() && s.host_name == self.name.trim()
    }

    fn start(&mut self, what: &str, job: impl FnOnce() -> Msg + Send + 'static) {
        self.error.clear();
        self.busy = Some(what.to_string());
        let tx = self.tx.clone();
        std::thread::spawn(move || {
            let _ = tx.send(job());
        });
    }

    fn load_peers(&mut self) {
        let Some(s) = self.joined.clone() else { return };
        self.start("正在找帳號裡的大腦…", move || Msg::Peers(list_brains(&s)));
    }

    fn on_msg(&mut self, m: Msg) {
        match m {
            Msg::Server(r) => {
                self.busy = None;
                match r {
                    Ok(u) => {
                        self.server = u.clone();
                        self.url = u;
                        self.focus = if self.user.is_empty() { 0 } else { 1 };
                        self.step = Step::Account;
                    }
                    Err(e) => self.error = e,
                }
            }
            Msg::Joined(r) => {
                self.busy = None;
                match r {
                    Ok(s) => {
                        self.joined = Some(s);
                        self.pass.clear();
                        match self.role {
                            Role::Hands => {
                                self.step = Step::Brain;
                                self.load_peers();
                            }
                            Role::Brain => self.step = Step::Confirm,
                        }
                    }
                    Err(e) => self.error = e,
                }
            }
            Msg::Peers(r) => {
                self.busy = None;
                match r {
                    Ok(p) => {
                        let want = if self.saved.hands_for.is_empty() { None } else { p.iter().position(|x| x.id == self.saved.hands_for) };
                        self.sel = want.or_else(|| p.iter().position(|x| x.online)).unwrap_or(0);
                        self.peers = p;
                    }
                    Err(e) => self.error = e,
                }
            }
            Msg::Progress(i, mark, note) => {
                if let Some(p) = self.progress.get_mut(i) {
                    p.1 = mark;
                    p.2 = note;
                }
            }
            Msg::Finished(tips) => {
                self.ok = !self.progress.iter().any(|p| p.1 == Mark::Fail);
                self.tips = tips;
                self.step = Step::Done;
            }
        }
    }

    fn back(&mut self) {
        self.error.clear();
        self.step = match self.step {
            Step::Role => {
                self.quit = true;
                Step::Role
            }
            Step::Name => Step::Role,
            Step::Server => Step::Name,
            Step::Account => Step::Server,
            Step::Brain => Step::Account,
            Step::Confirm if self.role == Role::Hands => Step::Brain,
            Step::Confirm => Step::Account,
            s => s,
        };
        if self.step == Step::Role {
            self.sel = if self.role == Role::Hands { 0 } else { 1 };
        }
    }

    fn enter(&mut self) {
        self.error.clear();
        match self.step {
            Step::Role => {
                self.role = if self.sel == 0 { Role::Hands } else { Role::Brain };
                self.step = Step::Name;
            }
            Step::Name => {
                let n = self.name.trim().to_string();
                if n.is_empty() || n.chars().count() > 60 {
                    self.error = "名字要 1 到 60 個字".into();
                    return;
                }
                self.name = n;
                self.step = Step::Server;
            }
            Step::Server => {
                let u = self.url.clone();
                self.start("正在找帳號伺服器…", move || Msg::Server(remote::check_server(&u)));
            }
            Step::Account => {
                // Enter on the name goes to the password first.
                if self.focus == 0 && self.pass.is_empty() && !self.can_reuse() {
                    self.focus = 1;
                    return;
                }
                let user = self.user.trim().to_string();
                if user.is_empty() {
                    self.error = "請輸入帳號".into();
                    self.focus = 0;
                    return;
                }
                if self.pass.is_empty() {
                    if self.can_reuse() {
                        self.joined = Some(self.saved.clone());
                        self.on_msg(Msg::Joined(Ok(self.saved.clone())));
                        return;
                    }
                    self.error = "請輸入密碼".into();
                    self.focus = 1;
                    return;
                }
                let mut base = self.saved.clone();
                base.host_name = self.name.clone();
                let (url, pass, create, invite) = (self.server.clone(), self.pass.clone(), self.create, self.invite.trim().to_string());
                self.start(if create { "正在建立帳號…" } else { "正在登入…" }, move || Msg::Joined(remote::relay_join(&base, &url, &user, &pass, create, &invite)));
            }
            Step::Brain => {
                self.brain = self.peers.get(self.sel).cloned();
                self.step = Step::Confirm;
            }
            Step::Confirm => {
                self.step = Step::Install;
                let plan = Plan { role: self.role, settings: self.joined.clone().unwrap_or_default(), brain: self.brain.clone(), env: self.env.clone(), service: self.service };
                self.progress = plan.steps().into_iter().map(|s| (s, Mark::Wait, String::new())).collect();
                let tx = self.tx.clone();
                std::thread::spawn(move || plan.run(&tx));
            }
            Step::Install => {}
            Step::Done => self.quit = true,
        }
    }

    fn key(&mut self, code: KeyCode, mods: KeyModifiers) {
        if mods.contains(KeyModifiers::CONTROL) && matches!(code, KeyCode::Char('c') | KeyCode::Char('d')) {
            self.quit = true;
            return;
        }
        if self.busy.is_some() || self.step == Step::Install {
            return;
        }
        let rows = match self.step {
            Step::Role => 2,
            Step::Brain => self.peers.len() + 1,
            Step::Account => {
                if self.create {
                    4
                } else {
                    3
                }
            }
            _ => 0,
        };
        match code {
            KeyCode::Esc => self.back(),
            KeyCode::Enter => self.enter(),
            KeyCode::Up | KeyCode::BackTab if rows > 0 => {
                if self.step == Step::Account {
                    self.focus = (self.focus + rows - 1) % rows;
                } else {
                    self.sel = (self.sel + rows - 1) % rows;
                }
            }
            KeyCode::Down | KeyCode::Tab if rows > 0 => {
                if self.step == Step::Account {
                    self.focus = (self.focus + 1) % rows;
                } else {
                    self.sel = (self.sel + 1) % rows;
                }
            }
            KeyCode::Char('r') if self.step == Step::Brain => self.load_peers(),
            KeyCode::Char(' ') if self.step == Step::Account && self.focus == 2 => {
                self.create = !self.create;
                if !self.create && self.focus > 2 {
                    self.focus = 2;
                }
            }
            KeyCode::Char(c) if !mods.contains(KeyModifiers::CONTROL) => self.type_text(&c.to_string()),
            KeyCode::Char('u') if mods.contains(KeyModifiers::CONTROL) => {
                if let Some(f) = self.text_field() {
                    f.clear();
                }
            }
            KeyCode::Backspace => {
                if let Some(f) = self.text_field() {
                    f.pop();
                }
            }
            _ => {}
        }
    }

    fn text_field(&mut self) -> Option<&mut String> {
        match (self.step, self.focus) {
            (Step::Name, _) => Some(&mut self.name),
            (Step::Server, _) => Some(&mut self.url),
            (Step::Account, 0) => Some(&mut self.user),
            (Step::Account, 1) => Some(&mut self.pass),
            (Step::Account, 3) => Some(&mut self.invite),
            _ => None,
        }
    }

    fn type_text(&mut self, s: &str) {
        let s: String = s.chars().filter(|c| !c.is_control()).collect();
        if let Some(f) = self.text_field() {
            f.push_str(&s);
        }
    }
}

/// The account's AnyBots that can be a brain (not this one, not one showing another's bots).
fn list_brains(s: &Settings) -> Result<Vec<Peer>, String> {
    let all = remote::peers(s)?;
    let mut v: Vec<Peer> = all
        .iter()
        .filter(|h| h["id"].as_str() != Some(s.host_id.as_str()) && h["uses"].as_str().unwrap_or("").is_empty())
        .map(|h| Peer {
            id: h["id"].as_str().unwrap_or("").into(),
            name: h["name"].as_str().unwrap_or("").into(),
            online: h["online"].as_bool().unwrap_or(false),
            last: h["last_seen_text"].as_str().unwrap_or("").into(),
        })
        .collect();
    v.sort_by_key(|p| !p.online);
    Ok(v)
}

// ---------- doing it ----------

struct Plan {
    role: Role,
    settings: Settings,
    brain: Option<Peer>,
    env: Env,
    service: bool,
}

impl Plan {
    fn steps(&self) -> Vec<String> {
        let mut v = vec!["儲存設定".to_string(), "開機自動執行".into(), "連上帳號伺服器".into()];
        if let (Role::Hands, Some(b)) = (self.role, &self.brain) {
            v.push(format!("大腦「{}」", b.name));
        }
        v
    }

    fn run(&self, tx: &Sender<Msg>) {
        let say = |i: usize, m: Mark, n: &str| {
            let _ = tx.send(Msg::Progress(i, m, n.to_string()));
        };
        // 1. Settings (this AnyBot's own file; the service reads it).
        say(0, Mark::Run, "");
        if self.service {
            let _ = systemctl(&["stop", UNIT]);
        }
        let mut st = State::load();
        let mut r = self.settings.clone();
        match self.role {
            Role::Hands => {
                r.device_link = true;
                match &self.brain {
                    Some(b) => {
                        r.hands_for = b.id.clone();
                        r.hands_for_name = b.name.clone();
                    }
                    None => {
                        r.hands_for.clear();
                        r.hands_for_name.clear();
                    }
                }
            }
            Role::Brain => {
                // A brain shows its own bots and lends its hands to no one.
                r.brain_id.clear();
                r.brain_name.clear();
                r.hands_for.clear();
                r.hands_for_name.clear();
                r.device_link = false;
            }
        }
        st.remote = r.clone();
        st.save();
        say(0, Mark::Ok, &format!("存在 {}", State::path().display()));

        // 2. Start with the computer.
        say(1, Mark::Run, "");
        let started = if !self.env.linux {
            say(1, Mark::Warn, "Mac 和 Windows：打開 AnyBot App 就會用這些設定連上（設定 › 手機與帳號）。");
            false
        } else if !self.service {
            say(1, Mark::Warn, "這台沒有 systemd：請用「anybot --serve」啟動，或把它加到開機執行。");
            false
        } else {
            match self.install_service() {
                Ok(note) => {
                    say(1, Mark::Ok, &note);
                    true
                }
                Err(e) => {
                    say(1, Mark::Fail, &e);
                    false
                }
            }
        };

        // 3. The account server sees it.
        if started {
            say(2, Mark::Run, "");
            let t0 = Instant::now();
            let mut seen = false;
            while t0.elapsed() < Duration::from_secs(40) {
                if let Ok(all) = remote::peers(&r) {
                    if all.iter().any(|h| h["id"].as_str() == Some(r.host_id.as_str()) && h["online"].as_bool() == Some(true)) {
                        seen = true;
                        break;
                    }
                }
                std::thread::sleep(Duration::from_secs(1));
            }
            if seen {
                say(2, Mark::Ok, &format!("已連線（{} 秒）", t0.elapsed().as_secs().max(1)));
            } else {
                say(2, Mark::Fail, "40 秒內沒有連上。看看紀錄：journalctl --user -u anybot -n 50");
            }
        } else {
            say(2, Mark::Warn, "啟動 AnyBot 後就會連上。");
        }

        // 4. The brain is there.
        if let (Role::Hands, Some(b)) = (self.role, &self.brain) {
            say(3, Mark::Run, "");
            let online = remote::peers(&r).ok().and_then(|all| all.iter().find(|h| h["id"].as_str() == Some(b.id.as_str())).map(|h| h["online"].as_bool() == Some(true)));
            match online {
                Some(true) => say(3, Mark::Ok, "在線上。大腦約一分鐘內就會看到這台，它的 Bot 就能用這台了。"),
                Some(false) => say(3, Mark::Warn, "目前離線；它開機連上後就能用這台。"),
                None => say(3, Mark::Warn, "帳號裡找不到它了（被移除了？）"),
            }
        }

        let mut tips = vec![];
        match self.role {
            Role::Hands => tips.push(format!("在大腦上跟 Bot 說「用 {} 的瀏覽器打開…」或「看一下 {} 的畫面」試試。", r.host_name, r.host_name)),
            Role::Brain => tips.push("其他電腦：AnyBot › 設定 › 手機與帳號，登入同一個帳號，在「大腦」選這台。沒有視窗的 Linux：anybot setup 選「手腳」。".into()),
        }
        if started {
            tips.push(String::new());
            tips.push("看狀態\tsystemctl --user status anybot".into());
            tips.push("看紀錄\tjournalctl --user -u anybot -f".into());
        }
        tips.push("改設定\tanybot setup".into());
        if started && !lingering() {
            tips.push(String::new());
            tips.push(format!("登出或重開機後也要繼續跑，請執行一次：sudo loginctl enable-linger {}", std::env::var("USER").unwrap_or_default()));
        }
        let _ = tx.send(Msg::Finished(tips));
    }

    /// A small launcher and a systemd user service that runs it.
    fn install_service(&self) -> Result<String, String> {
        let home = dirs::home_dir().ok_or("找不到家目錄")?;
        let exe = std::env::current_exe().and_then(|p| p.canonicalize()).map_err(|e| format!("找不到 AnyBot 程式：{e}"))?;
        let bin = home.join(".local/bin");
        std::fs::create_dir_all(&bin).map_err(|e| format!("建立 {} 失敗：{e}", bin.display()))?;
        let launcher = bin.join("anybot-run");
        std::fs::write(&launcher, launcher_script(self.role, &exe, &self.env)).map_err(|e| format!("寫入 {} 失敗：{e}", launcher.display()))?;
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            let _ = std::fs::set_permissions(&launcher, std::fs::Permissions::from_mode(0o755));
        }
        let units = home.join(".config/systemd/user");
        std::fs::create_dir_all(&units).map_err(|e| e.to_string())?;
        // An older setup (deploy/linux/hands.sh) used another service name.
        if units.join("anybot-hands.service").exists() {
            let _ = systemctl(&["disable", "--now", "anybot-hands.service"]);
            let _ = std::fs::remove_file(units.join("anybot-hands.service"));
        }
        let what = match self.role {
            Role::Hands => "手腳",
            Role::Brain => "大腦",
        };
        let unit = format!(
            "[Unit]\nDescription=AnyBot（{what}）\nAfter=network-online.target graphical-session.target\nWants=network-online.target\n\n[Service]\nExecStart={}\nRestart=always\nRestartSec=5\n\n[Install]\nWantedBy=default.target\n",
            launcher.display()
        );
        std::fs::write(units.join(UNIT), unit).map_err(|e| e.to_string())?;
        systemctl(&["daemon-reload"])?;
        systemctl(&["enable", UNIT])?;
        systemctl(&["restart", UNIT])?;
        Ok(format!("systemd 使用者服務「anybot」，已啟動（{}）", launcher.display()))
    }
}

fn launcher_script(role: Role, exe: &std::path::Path, env: &Env) -> String {
    let q = |s: &str| format!("'{}'", s.replace('\'', "'\\''"));
    let mut s = String::from("#!/bin/sh\n# Started by systemd (anybot.service); written by `anybot setup`.\n");
    s += "export LANG=\"${LANG:-C.UTF-8}\"\n";
    if let Ok(d) = std::env::var("ANYBOT_DATA_DIR") {
        s += &format!("export ANYBOT_DATA_DIR={}\n", q(&d));
    }
    let bin = q(&exe.display().to_string());
    if role == Role::Hands {
        s += "# The accessibility bus, so bots can read apps' buttons instead of only looking at pixels.\n";
        s += "export NO_AT_BRIDGE=0 GTK_A11Y=atspi QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1\n";
        if env.has_display() && env.display != "wayland" && env.display != "desktop" {
            s += &format!("# The screen this computer had when it was set up.\nexport DISPLAY=\"${{DISPLAY:-{}}}\"\n", env.display);
            if let Ok(x) = std::env::var("XAUTHORITY") {
                s += &format!("export XAUTHORITY=\"${{XAUTHORITY:-{x}}}\"\n");
            }
        }
        s += "if [ -z \"$DISPLAY\" ] && [ -z \"$WAYLAND_DISPLAY\" ] && command -v xvfb-run >/dev/null; then\n";
        s += "  # No screen: a virtual one, a window manager, and a session bus for the accessibility bus.\n";
        s += &format!("  exec xvfb-run -a -s \"-screen 0 1440x900x24\" dbus-run-session -- sh -c 'command -v openbox >/dev/null && (openbox >/dev/null 2>&1 &); exec \"$0\" --serve' {bin}\n");
        s += "fi\n";
    }
    s += &format!("exec {bin} --serve\n");
    s
}

fn systemctl(args: &[&str]) -> Result<(), String> {
    let o = std::process::Command::new("systemctl").arg("--user").args(args).output().map_err(|e| format!("執行 systemctl 失敗：{e}"))?;
    if o.status.success() {
        Ok(())
    } else {
        Err(format!("systemctl {} 失敗：{}", args.join(" "), String::from_utf8_lossy(&o.stderr).trim()))
    }
}

fn lingering() -> bool {
    let user = std::env::var("USER").unwrap_or_default();
    std::process::Command::new("loginctl").args(["show-user", &user, "-p", "Linger"]).output().map(|o| String::from_utf8_lossy(&o.stdout).contains("Linger=yes")).unwrap_or(true)
}

// ---------- entry ----------

pub fn run(args: &[String]) -> i32 {
    let flag = |k: &str| args.iter().position(|a| a == k).and_then(|i| args.get(i + 1)).cloned();
    if args.iter().any(|a| a == "-h" || a == "--help") {
        println!("anybot setup：把這台設成大腦，或大腦的手腳。\n\n在終端機裡直接執行會一步一步問你。給程式用：\n  anybot setup --role hands|brain --name 名字 --server 網址 --user 帳號 [--brain 大腦名字|any]\n               [--create] [--invite 碼] [--no-service] [--password-stdin]\n  密碼放在 ANYBOT_ACCOUNT_PASSWORD，或加 --password-stdin 從標準輸入讀。");
        return 0;
    }
    if flag("--role").is_some() || !std::io::stdin().is_terminal() || !std::io::stdout().is_terminal() {
        return run_plain(args);
    }
    let mut w = Wiz::new();
    if args.iter().any(|a| a == "--no-service") {
        w.service = false;
    }
    let mut out = std::io::stdout();
    if terminal::enable_raw_mode().is_err() {
        return run_plain(args);
    }
    let _ = execute!(out, terminal::EnterAlternateScreen, cursor::Hide, event::EnableBracketedPaste);
    let restore = |out: &mut std::io::Stdout| {
        let _ = execute!(out, event::DisableBracketedPaste, cursor::Show, terminal::LeaveAlternateScreen);
        let _ = terminal::disable_raw_mode();
    };
    let rx = w.rx.take().expect("channel");
    let mut dirty = true;
    while !w.quit {
        if dirty {
            if w.render(&mut out).is_err() {
                break;
            }
            dirty = false;
        }
        if event::poll(Duration::from_millis(90)).unwrap_or(false) {
            match event::read() {
                Ok(Event::Key(k)) if k.kind != KeyEventKind::Release => w.key(k.code, k.modifiers),
                Ok(Event::Paste(s)) => w.type_text(&s),
                _ => {}
            }
            dirty = true;
        }
        while let Ok(m) = rx.try_recv() {
            w.on_msg(m);
            dirty = true;
        }
        if w.busy.is_some() || w.step == Step::Install {
            w.spin += 1;
            dirty = true;
        }
    }
    restore(&mut out);
    // Leave a short note behind in the terminal.
    if w.step == Step::Done {
        let (mark, c) = if w.ok { ("✓", GOOD) } else { ("✗", BAD) };
        let _ = execute!(out, SetForegroundColor(c), Print(format!("{mark} ")), ResetColor);
        println!(
            "{}",
            match (w.ok, w.role) {
                (true, Role::Hands) => format!("「{}」現在是{}的手腳。", w.name, w.brain.as_ref().map(|b| format!("大腦「{}」", b.name)).unwrap_or_else(|| "帳號裡大腦".into())),
                (true, Role::Brain) => format!("「{}」現在是大腦。", w.name),
                (false, _) => "設定沒有完成，再執行一次 anybot setup 看看。".into(),
            }
        );
        for (label, mark, note) in &w.progress {
            if matches!(mark, Mark::Fail | Mark::Warn) {
                println!("  {label}：{note}");
            }
        }
        0
    } else {
        println!("沒有改任何設定。");
        1
    }
}

/// No terminal (or --role given): the same, from flags, printed line by line.
fn run_plain(args: &[String]) -> i32 {
    let flag = |k: &str| args.iter().position(|a| a == k).and_then(|i| args.get(i + 1)).cloned();
    let fail = |m: &str| {
        eprintln!("✗ {m}");
        1
    };
    let role = match flag("--role").as_deref() {
        Some("hands") | Some("手腳") => Role::Hands,
        Some("brain") | Some("大腦") => Role::Brain,
        _ => return fail("請用 --role hands 或 --role brain（在終端機直接執行 anybot setup 會一步一步問）"),
    };
    let saved = State::load().remote;
    let name = flag("--name").unwrap_or_else(|| if saved.host_name.is_empty() { remote::default_host_name() } else { saved.host_name.clone() });
    let Some(server) = flag("--server").or_else(|| (!saved.relay_url.is_empty()).then(|| saved.relay_url.clone())) else { return fail("請用 --server 給帳號伺服器的網址") };
    let server = match remote::check_server(&server) {
        Ok(u) => u,
        Err(e) => return fail(&e),
    };
    println!("✓ 帳號伺服器 {server}");
    let user = flag("--user").unwrap_or_else(|| saved.relay_user.clone());
    let mut pass = std::env::var("ANYBOT_ACCOUNT_PASSWORD").unwrap_or_default();
    if args.iter().any(|a| a == "--password-stdin") {
        let mut s = String::new();
        let _ = std::io::stdin().read_line(&mut s);
        pass = s.trim_end_matches(['\n', '\r']).to_string();
    }
    let joined = if pass.is_empty() && !saved.host_token.is_empty() && saved.relay_url == server && saved.relay_user == user && saved.host_name == name {
        saved.clone()
    } else {
        if user.is_empty() || pass.is_empty() {
            return fail("請給 --user，密碼放在 ANYBOT_ACCOUNT_PASSWORD（或用 --password-stdin）");
        }
        let mut base = saved.clone();
        base.host_name = name.clone();
        match remote::relay_join(&base, &server, &user, &pass, args.iter().any(|a| a == "--create"), &flag("--invite").unwrap_or_default()) {
            Ok(s) => s,
            Err(e) => return fail(&e),
        }
    };
    println!("✓ 已登入帳號 {user}（這台叫「{name}」）");
    let mut brain = None;
    if role == Role::Hands {
        match flag("--brain").as_deref() {
            None | Some("any") | Some("") => {}
            Some(want) => match list_brains(&joined) {
                Ok(list) => match list.into_iter().find(|p| p.name == want) {
                    Some(p) => brain = Some(p),
                    None => return fail(&format!("帳號裡沒有叫「{want}」的 AnyBot")),
                },
                Err(e) => return fail(&e),
            },
        }
    }
    let env = Env::detect();
    let plan = Plan { role, settings: joined, brain, service: env.systemd && !args.iter().any(|a| a == "--no-service"), env };
    let steps = plan.steps();
    let (tx, rx) = channel();
    std::thread::spawn(move || plan.run(&tx));
    let mut failed = false;
    for m in rx {
        match m {
            Msg::Progress(i, mark, note) if mark != Mark::Run && mark != Mark::Wait => {
                let icon = match mark {
                    Mark::Ok => "✓",
                    Mark::Warn => "!",
                    _ => "✗",
                };
                failed |= mark == Mark::Fail;
                println!("{icon} {}{}", steps.get(i).cloned().unwrap_or_default(), if note.is_empty() { String::new() } else { format!("：{note}") });
            }
            Msg::Finished(tips) => {
                for t in tips.iter().filter(|t| !t.is_empty()) {
                    println!("  {}", t.replace('\t', "  "));
                }
                break;
            }
            _ => {}
        }
    }
    if failed {
        1
    } else {
        0
    }
}

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

    #[test]
    fn wraps_chinese_by_width() {
        let lines = wrap("讓大腦的 Bot 使用這台電腦", 10);
        assert!(lines.iter().all(|l| l.width() <= 10), "{lines:?}");
        assert_eq!(lines.concat(), "讓大腦的 Bot 使用這台電腦");
        let l = wrap("一二三四五。", 5);
        assert!(!l[1].starts_with('。'), "{l:?}");
        let l = wrap("一二三四（五）。", 5);
        assert!(l.iter().all(|x| !x.starts_with('）') && !x.starts_with('。')), "{l:?}");
    }

    #[test]
    fn launcher_makes_a_screen_when_there_is_none() {
        let env = Env { linux: true, display: String::new(), systemd: true, xvfb: true };
        let s = launcher_script(Role::Hands, std::path::Path::new("/home/a b/anybot"), &env);
        assert!(s.contains("xvfb-run") && s.contains("'/home/a b/anybot'") && s.ends_with("exec '/home/a b/anybot' --serve\n"));
        let brain = launcher_script(Role::Brain, std::path::Path::new("/x/anybot"), &env);
        assert!(!brain.contains("xvfb-run"));
    }

    #[test]
    fn every_step_fits_a_narrow_terminal() {
        let mut w = Wiz::new();
        w.peers = vec![Peer { id: "1".into(), name: "很長很長很長很長很長很長很長很長的大腦名字".into(), online: true, last: String::new() }];
        for step in [Step::Role, Step::Name, Step::Server, Step::Account, Step::Brain, Step::Confirm, Step::Done] {
            w.step = step;
            for l in w.body(40) {
                assert!(width(&clip(l, 40)) <= 40);
            }
        }
    }
}