// `anybot setup`: join this computer to your AnyBot, as hands for your brain (or as a brain), from
// a terminal (over SSH, or on a computer without a window). As little to answer as possible:
//
//   anybot setup https://anybot.example.com 482913   the line 「加一台電腦」 shows on the phone or in
//                                                    the app: nothing to answer at all
//   anybot setup                                     one screen: the address and the code (or the
//                                                    account and password instead)
//   anybot setup --brain …                           this computer is a brain, not hands
//
// Then it saves the settings, makes AnyBot start with the computer (systemd; a virtual screen when
// there is none), and waits until the account server and the brain see it. For scripts:
//   anybot setup --server URL --user NAME [--brain-name 雲端大腦] [--no-service]
// with the password in ANYBOT_ACCOUNT_PASSWORD.

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";

/// Write a file all at once, as far as the filesystem allows: tmp file + rename. A Ctrl+C in
/// the middle of installing used to leave a half-written launcher/unit behind, and systemd
/// then ran (or refused to run) a broken service with no easy way to see why.
fn write_atomic(path: &std::path::Path, body: String) -> std::io::Result<()> {
    let tmp = path.with_extension("anybot-tmp");
    std::fs::write(&tmp, body)?;
    std::fs::rename(&tmp, path)?;
    Ok(())
}

/// Quote a path for a systemd ExecStart line: a home folder with spaces (or a quote sign)
/// made the unit fail to start with no way to see why.
fn systemd_quote(p: &std::path::Path) -> String {
    let mut out = String::from("\"");
    for c in p.display().to_string().chars() {
        match c {
            '"' | '$' | '\\' | '`' => {
                out.push('\\');
                out.push(c);
            }
            c => out.push(c),
        }
    }
    out.push('"');
    out
}

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

#[derive(Clone, Copy, PartialEq, Debug)]
enum Step {
    Form,
    Brain,
    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,
}

/// Joining an account: its settings, the brain a code was made for, the brains to choose from.
type Joining = Result<(Settings, Option<Peer>, Vec<Peer>), String>;

enum Msg {
    /// Joined the account; with a code, the brain it was made for.
    Joined(Box<Joining>),
    Progress(usize, Mark, String),
    Finished(Vec<String>),
}

/// What this computer has.
#[derive(Clone)]
struct Env {
    linux: bool,
    display: String,
    systemd: 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 }
    }
    fn has_display(&self) -> bool {
        !self.display.is_empty()
    }
}

// ---------- 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,
    /// Sign in with the account and password instead of a code.
    password: bool,
    url: String,
    code: String,
    user: String,
    pass: String,
    focus: usize,
    joined: Option<Settings>,
    peers: Vec<Peer>,
    sel: usize,
    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,
    name: Option<String>,
}

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

    /// The rows of the form: text fields, then the switch to the other way of signing in.
    fn rows(&self) -> usize {
        if self.password {
            4
        } else {
            3
        }
    }

    fn title(&self) -> (String, String) {
        match self.step {
            Step::Form => (
                match self.role {
                    Role::Hands => "把這台電腦接到你的 AnyBot".into(),
                    Role::Brain => "把這台設成大腦".into(),
                },
                if self.password { "用手機登入 AnyBot 的那個網址和帳號。".into() } else { "在手機或電腦的 AnyBot 按「加一台電腦」，會看到網址和配對碼。".into() },
            ),
            Step::Brain => ("要給哪個大腦用？".into(), "帳號裡有好幾台，選一台：只有它能用這台電腦。".into()),
            Step::Install => ("正在設定…".into(), String::new()),
            Step::Done => (if self.ok { "好了".into() } else { "沒有完成".into() }, 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::Form => {
                b.push(self.field("網址", &self.url, self.focus == 0, false, "https://…"));
                if self.password {
                    b.push(self.field("帳號", &self.user, self.focus == 1, false, ""));
                    b.push(self.field("密碼", &self.pass, self.focus == 2, true, ""));
                } else {
                    b.push(self.field("配對碼", &self.code, self.focus == 1, false, "6 位數字"));
                }
                b.push(vec![]);
                let on = self.focus == self.rows() - 1;
                let other = if self.password { "改用配對碼 ›" } else { "沒有配對碼？用帳號密碼登入 ›" };
                b.push(vec![if on { colored("❯ ", ACC) } else { plain("  ") }, sp(other, Some(if on { ACC } else { DIM }), false)]);
            }
            Step::Brain => {
                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]);
                }
            }
            Step::Install | Step::Done => b.extend(progress_lines(&self.progress, &self.tips, self.spin, w)),
        }
        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 (i, l) in wrap(&self.error, w.saturating_sub(2)).into_iter().enumerate() {
                b.push(vec![colored(if i == 0 { "✗ " } else { "  " }, BAD), colored(l, BAD)]);
            }
        }
        b
    }

    fn keys(&self) -> &'static str {
        if self.busy.is_some() || self.step == Step::Install {
            return "Ctrl+C 離開";
        }
        match self.step {
            Step::Form => "Enter 連線   ↑↓ 換欄位   Esc 離開",
            Step::Brain => "↑↓ 選擇   Enter 確定",
            _ => "Enter 離開",
        }
    }

    fn render(&self, out: &mut impl Write) -> std::io::Result<()> {
        let (cols, rows) = terminal::size().unwrap_or((80, 24));
        let (title, sub) = self.title();
        let lines = card_page(cols as usize, &title, &sub, |w| self.body(w), self.keys());
        draw(out, lines, cols as usize, rows as usize)
    }

    // ----- moving along -----

    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 submit(&mut self) {
        let base = base_settings(self.name.clone());
        let url = self.url.clone();
        if self.password {
            let (user, pass) = (self.user.trim().to_string(), self.pass.clone());
            if user.is_empty() || pass.is_empty() {
                self.error = "請輸入帳號和密碼".into();
                return;
            }
            self.start("正在登入…", move || Msg::Joined(Box::new(join_with_password(&base, &url, &user, &pass))));
        } else {
            let code: String = self.code.chars().filter(|c| c.is_ascii_digit()).collect();
            if code.len() != 6 {
                self.error = "配對碼是 6 位數字".into();
                self.focus = 1;
                return;
            }
            self.start("正在連線…", move || Msg::Joined(Box::new(remote::pair_claim(&base, &url, &code).map(|s| (s.clone(), brain_of(&s), vec![])))));
        }
    }

    fn install(&mut self) {
        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));
    }

    fn on_msg(&mut self, m: Msg) {
        match m {
            Msg::Joined(r) => {
                self.busy = None;
                match *r {
                    Ok((s, brain, choices)) => {
                        self.joined = Some(s);
                        self.pass.clear();
                        if self.role == Role::Hands && brain.is_none() && choices.len() > 1 {
                            self.sel = choices.iter().position(|p| p.online).unwrap_or(0);
                            self.peers = choices;
                            self.step = Step::Brain;
                        } else {
                            self.brain = brain;
                            self.install();
                        }
                    }
                    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 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;
        }
        if self.step == Step::Done {
            if matches!(code, KeyCode::Enter | KeyCode::Esc | KeyCode::Char('q')) {
                self.quit = true;
            }
            return;
        }
        if self.step == Step::Brain {
            let n = self.peers.len().max(1);
            match code {
                KeyCode::Up => self.sel = (self.sel + n - 1) % n,
                KeyCode::Down => self.sel = (self.sel + 1) % n,
                KeyCode::Enter => {
                    self.brain = self.peers.get(self.sel).cloned();
                    self.install();
                }
                _ => {}
            }
            return;
        }
        let rows = self.rows();
        match code {
            KeyCode::Esc => self.quit = true,
            KeyCode::Up | KeyCode::BackTab => self.focus = (self.focus + rows - 1) % rows,
            KeyCode::Down | KeyCode::Tab => self.focus = (self.focus + 1) % rows,
            KeyCode::Enter if self.focus == rows - 1 => {
                // The switch between a code and the password.
                self.password = !self.password;
                self.error.clear();
                self.focus = 1;
            }
            KeyCode::Enter if self.focus + 2 < rows && !self.field_done() => self.focus += 1,
            KeyCode::Enter => self.submit(),
            KeyCode::Char('u') if mods.contains(KeyModifiers::CONTROL) => {
                if let Some(f) = self.text_field() {
                    f.clear();
                }
            }
            KeyCode::Char(c) if !mods.contains(KeyModifiers::CONTROL) => self.type_text(&c.to_string()),
            KeyCode::Backspace => {
                if let Some(f) = self.text_field() {
                    f.pop();
                }
            }
            _ => {}
        }
    }

    /// Every text field is filled (Enter connects from anywhere then).
    fn field_done(&self) -> bool {
        !self.url.trim().is_empty() && if self.password { !self.user.trim().is_empty() && !self.pass.is_empty() } else { !self.code.trim().is_empty() }
    }

    fn text_field(&mut self) -> Option<&mut String> {
        match (self.password, self.focus) {
            (_, 0) => Some(&mut self.url),
            (false, 1) => Some(&mut self.code),
            (true, 1) => Some(&mut self.user),
            (true, 2) => Some(&mut self.pass),
            _ => None,
        }
    }

    fn type_text(&mut self, s: &str) {
        let s: String = s.chars().filter(|c| !c.is_control()).collect();
        // A pasted 「anybot setup 網址 配對碼」 line (or the 「curl … | sh -s -- hands 網址 配對碼」 one)
        // fills both.
        let words: Vec<&str> = s.split_whitespace().collect();
        let n = words.len();
        if n >= 2 && words[n - 1].chars().all(|c| c.is_ascii_digit()) && words[n - 2].contains("://") && !self.password {
            self.url = words[n - 2].to_string();
            self.code = words[n - 1].to_string();
            self.focus = 1;
            return;
        }
        if let Some(f) = self.text_field() {
            f.push_str(&s);
        }
    }
}

/// The brain a pairing code was made for.
fn brain_of(s: &Settings) -> Option<Peer> {
    (!s.hands_for.is_empty()).then(|| Peer { id: s.hands_for.clone(), name: s.hands_for_name.clone(), online: true, last: String::new() })
}

/// Sign in with the password; the brain is picked when there is only one to pick.
fn join_with_password(base: &Settings, url: &str, user: &str, pass: &str) -> Result<(Settings, Option<Peer>, Vec<Peer>), String> {
    let url = remote::check_server(url)?;
    let s = remote::relay_join(base, &url, user, pass, false, "")?;
    let list = list_brains(&s).unwrap_or_default();
    let online: Vec<&Peer> = list.iter().filter(|p| p.online).collect();
    let brain = if list.len() == 1 { list.first().cloned() } else if online.len() == 1 { Some(online[0].clone()) } else { None };
    Ok((s, brain, list))
}

/// A page: the name on top, one card, the keys below.
fn card_page(cols: usize, title: &str, sub: &str, body: impl Fn(usize) -> Vec<Line>, keys: &str) -> Vec<Line> {
    let w = cols.saturating_sub(4).clamp(36, 78);
    let inner = w - 4;
    let mut lines: Vec<Line> = vec![vec![], vec![plain("  "), colored("◆ ", ACC), strong("AnyBot")], vec![]];
    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(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(keys)]);
    lines
}

fn draw(out: &mut impl Write, lines: Vec<Line>, cols: usize, rows: usize) -> std::io::Result<()> {
    queue!(out, terminal::BeginSynchronizedUpdate, terminal::Clear(terminal::ClearType::All))?;
    for (y, l) in lines.into_iter().enumerate().take(rows) {
        queue!(out, cursor::MoveTo(0, y as u16))?;
        print_line(out, l, cols)?;
    }
    queue!(out, terminal::EndSynchronizedUpdate)?;
    out.flush()
}

fn print_line(out: &mut impl Write, l: Line, cols: usize) -> std::io::Result<()> {
    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)?;
    }
    Ok(())
}

/// The steps with their marks, then the tips.
fn progress_lines(progress: &[(String, Mark, String)], tips: &[String], spin: usize, w: usize) -> Vec<Line> {
    let mut b: Vec<Line> = vec![];
    for (label, mark, note) in progress {
        let icon = match mark {
            Mark::Wait => dim("·"),
            Mark::Run => colored(SPIN[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 f: fn(String) -> Span = match mark {
                Mark::Fail => |s| colored(s, BAD),
                Mark::Warn => |s| colored(s, WARN),
                _ => dim,
            };
            b.extend(para(note, 2, w, f));
        }
    }
    if !tips.is_empty() {
        b.push(vec![]);
        for t in 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));
            }
        }
    }
    b
}

/// 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() && h["hands"].as_bool() != Some(true))
        .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]);
        }
        // No other AnyBot may be using this folder while the settings are written (a window
        // would overwrite them with its own copy). The service was just stopped: give it a
        // moment to let go.
        let folder = match crate::lock::take(Duration::from_secs(10)) {
            Ok(l) => l,
            Err(e) => {
                say(0, Mark::Fail, &e);
                let _ = tx.send(Msg::Finished(vec!["關掉另一個 AnyBot 之後，再執行一次 anybot setup。".into()]));
                return;
            }
        };
        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();
        // Let go before the service starts again (it takes the folder next).
        drop(folder);
        say(0, Mark::Ok, "");

        // 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 › 一般 › 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 › 一般 › 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");
        write_atomic(&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",
            systemd_quote(&launcher)
        );
        write_atomic(&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()))
    }
}

/// `anybot setup --refresh-service` (install.sh runs it after an update): write the start script
/// again — a newer AnyBot may start differently — and restart. The computer stays joined as it was,
/// and a screen remembered at setup stays.
fn refresh_service() -> i32 {
    let Some(home) = dirs::home_dir() else { return 1 };
    let launcher = home.join(".local/bin/anybot-run");
    let Ok(old) = std::fs::read_to_string(&launcher) else {
        println!("這台沒有設成開機自動執行，不用更新服務。");
        return 0;
    };
    let role = if old.contains("accessibility bus") { Role::Hands } else { Role::Brain };
    let display = old.lines().find_map(|l| l.strip_prefix("export DISPLAY=\"${DISPLAY:-").and_then(|r| r.strip_suffix("}\""))).unwrap_or("").to_string();
    let env = Env { linux: cfg!(target_os = "linux"), display, systemd: true };
    let exe = match std::env::current_exe().and_then(|p| p.canonicalize()) {
        Ok(e) => e,
        Err(e) => {
            eprintln!("✗ 找不到 AnyBot 程式：{e}");
            return 1;
        }
    };
    if let Err(e) = write_atomic(&launcher, launcher_script(role, &exe, &env)) {
        eprintln!("✗ 寫入 {} 失敗：{e}", launcher.display());
        return 1;
    }
    match systemctl(&["restart", UNIT]) {
        Ok(_) => {
            println!("已更新並重新啟動 AnyBot 服務。");
            0
        }
        Err(e) => {
            eprintln!("✗ 重新啟動失敗：{e}");
            1
        }
    }
}

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=\"${LANG:-C.UTF-8}\"\n";
    if let Ok(d) = std::env::var("ANYBOT_DATA_DIR") {
        s += &format!("export ANYBOT_DATA_DIR={}\n", q(&d));
    }
    let bin = q(&exe.display().to_string());
    if role == Role::Hands {
        s += "# The accessibility bus, so bots can read apps' buttons instead of only looking at pixels.\n";
        s += "export NO_AT_BRIDGE=0 GTK_A11Y=atspi QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1\n";
        let real_screen = std::env::args().any(|a| a == "--real-screen");
        if env.has_display() && env.display != "wayland" && env.display != "desktop" {
            s += &format!("# The screen this computer had when it was set up.\nexport DISPLAY=\"${{DISPLAY:-{}}}\"\n", env.display);
            if let Ok(x) = std::env::var("XAUTHORITY") {
                s += &format!("export XAUTHORITY=\"${{XAUTHORITY:-{x}}}\"\n");
            }
        } else if !real_screen {
            // Set up without a screen (over SSH, or on Wayland): the bots get a virtual screen of
            // their own, even when a desktop session is logged in here — nobody would be there to
            // answer its 「允許分享螢幕」 dialog. `anybot setup --real-screen` uses the desktop.
            s += "unset DISPLAY WAYLAND_DISPLAY XDG_SESSION_TYPE\n";
        }
        s += "if [ -z \"$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 ----------

/// Flags that take a value (so the value isn't read as the address or the code).
const VALUED: [&str; 4] = ["--server", "--user", "--name", "--brain-name"];

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：把這台電腦接到你的 AnyBot。\n\n  anybot setup 網址 配對碼     （手機或電腦的 AnyBot 按「加一台電腦」會給你這一行）\n  anybot setup                 一個畫面：填網址和配對碼（或帳號密碼）\n  加 --brain                   這台當大腦，不當手腳\n  加 --no-service              不設開機自動執行\n  加 --real-screen             讓 Bot 用這台登入中的桌面（預設用自己的虛擬螢幕）\n\n給程式用：anybot setup --server 網址 --user 帳號 [--brain-name 大腦名字]，密碼放在 ANYBOT_ACCOUNT_PASSWORD。");
        return 0;
    }
    if args.iter().any(|a| a == "--refresh-service") {
        return refresh_service();
    }
    let role = if args.iter().any(|a| a == "--brain") { Role::Brain } else { Role::Hands };
    let mut pos = vec![];
    let mut skip = false;
    for a in args {
        if skip {
            skip = false;
        } else if VALUED.contains(&a.as_str()) {
            skip = true;
        } else if !a.starts_with("--") {
            pos.push(a.clone());
        }
    }
    let service = !args.iter().any(|a| a == "--no-service");
    let name = flag("--name");
    if flag("--server").is_some() || flag("--user").is_some() {
        return run_script(role, &flag("--server").unwrap_or_default(), &flag("--user").unwrap_or_default(), flag("--brain-name"), name, service);
    }
    if pos.len() >= 2 {
        return run_code(role, &pos[0], &pos[1], name, service);
    }
    let name_for_screen = name.clone();
    if !std::io::stdin().is_terminal() || !std::io::stdout().is_terminal() {
        eprintln!("✗ 請用：anybot setup 網址 配對碼（在手機或電腦的 AnyBot 按「加一台電腦」）");
        return 1;
    }
    run_screen(role, service, name_for_screen)
}

/// The one-screen form, then the progress.
fn run_screen(role: Role, service: bool, name: Option<String>) -> i32 {
    let mut w = Wiz::new(role);
    w.name = name;
    w.service = service && w.env.systemd;
    let mut out = std::io::stdout();
    if terminal::enable_raw_mode().is_err() {
        eprintln!("✗ 這個終端機不能用互動畫面。請用：anybot setup 網址 配對碼");
        return 1;
    }
    let _ = execute!(out, terminal::EnterAlternateScreen, cursor::Hide, event::EnableBracketedPaste);
    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;
        }
    }
    let _ = execute!(out, event::DisableBracketedPaste, cursor::Show, terminal::LeaveAlternateScreen);
    let _ = terminal::disable_raw_mode();
    if w.step != Step::Done {
        println!("沒有改任何設定。");
        return 1;
    }
    // What happened stays in the terminal.
    let mut lines = vec![vec![], vec![plain("  "), colored("◆ ", ACC), strong("AnyBot")], vec![]];
    lines.extend(progress_lines(&w.progress, &w.tips, 0, 72).into_iter().map(|l| [vec![plain("  ")], l].concat()));
    for l in lines {
        let _ = print_line(&mut out, l, 200);
        println!();
    }
    if w.ok {
        0
    } else {
        1
    }
}

/// Print a line now (colors only in a terminal).
fn say(l: Line) {
    let mut out = std::io::stdout();
    if out.is_terminal() {
        let _ = print_line(&mut out, l, 400);
    } else {
        print!("{}", l.into_iter().map(|(s, _)| s).collect::<String>());
    }
    println!();
}

/// Shows a spinner on this line while `job` runs (in a terminal).
fn waiting<T: Send + 'static>(what: &str, job: impl FnOnce() -> T + Send + 'static) -> T {
    let (tx, rx) = channel();
    std::thread::spawn(move || {
        let _ = tx.send(job());
    });
    let tty = std::io::stdout().is_terminal();
    let mut n = 0;
    loop {
        if let Ok(v) = rx.recv_timeout(Duration::from_millis(100)) {
            if tty {
                print!("\r\x1b[K");
                let _ = std::io::stdout().flush();
            }
            return v;
        }
        if tty {
            let mut out = std::io::stdout();
            print!("\r\x1b[K  ");
            let _ = print_line(&mut out, vec![colored(SPIN[n % SPIN.len()], ACC), plain(" "), colored(what.to_string(), ACC)], 200);
            let _ = out.flush();
        }
        n += 1;
    }
}

fn header() {
    say(vec![]);
    say(vec![plain("  "), colored("◆ ", ACC), strong("AnyBot")]);
    say(vec![]);
}

fn base_settings(name: Option<String>) -> Settings {
    let mut base = State::load().remote;
    if let Some(n) = name.filter(|n| !n.trim().is_empty()) {
        base.host_name = n.trim().chars().take(60).collect();
    }
    if base.host_name.is_empty() {
        base.host_name = remote::default_host_name();
    }
    base
}

/// `anybot setup 網址 配對碼`: nothing to answer.
fn run_code(role: Role, url: &str, code: &str, name: Option<String>, service: bool) -> i32 {
    header();
    let base = base_settings(name);
    let (url, code) = (url.to_string(), code.chars().filter(|c| c.is_ascii_digit()).collect::<String>());
    let r = waiting("正在連線…", move || remote::pair_claim(&base, &url, &code));
    let s = match r {
        Ok(s) => s,
        Err(e) => {
            say(vec![plain("  "), colored("✗ ", BAD), colored(e, BAD)]);
            say(vec![plain("    "), dim("在手機或電腦的 AnyBot 按「加一台電腦」拿新的一行再試。")]);
            return 1;
        }
    };
    say(vec![plain("  "), colored("✓ ", GOOD), plain(format!("加入帳號 {}（這台叫「{}」）", s.relay_user, s.host_name))]);
    let brain = brain_of(&s);
    finish(role, s, brain, service)
}

/// Scripts: the account and password.
fn run_script(role: Role, server: &str, user: &str, brain_name: Option<String>, name: Option<String>, service: bool) -> i32 {
    header();
    let pass = std::env::var("ANYBOT_ACCOUNT_PASSWORD").unwrap_or_default();
    if server.is_empty() || user.is_empty() || pass.is_empty() {
        say(vec![plain("  "), colored("✗ 請給 --server 和 --user，密碼放在 ANYBOT_ACCOUNT_PASSWORD", BAD)]);
        return 1;
    }
    let base = base_settings(name);
    let (server, user2) = (server.to_string(), user.to_string());
    let (s, mut brain, list) = match waiting("正在登入…", move || join_with_password(&base, &server, &user2, &pass)) {
        Ok(v) => v,
        Err(e) => {
            say(vec![plain("  "), colored("✗ ", BAD), colored(e, BAD)]);
            return 1;
        }
    };
    say(vec![plain("  "), colored("✓ ", GOOD), plain(format!("登入帳號 {user}（這台叫「{}」）", s.host_name))]);
    if let Some(want) = brain_name {
        match list.into_iter().find(|p| p.name == want) {
            Some(p) => brain = Some(p),
            None => {
                say(vec![plain("  "), colored(format!("✗ 帳號裡沒有叫「{want}」的 AnyBot"), BAD)]);
                return 1;
            }
        }
    }
    finish(role, s, brain, service)
}

/// Save, start with the computer, check; printed line by line.
fn finish(role: Role, s: Settings, brain: Option<Peer>, service: bool) -> i32 {
    let env = Env::detect();
    let plan = Plan { role, settings: s, brain, service: service && env.systemd, env };
    let steps = plan.steps();
    let (tx, rx) = channel();
    std::thread::spawn(move || plan.run(&tx));
    let mut failed = false;
    let mut current = String::new();
    loop {
        let m = if std::io::stdout().is_terminal() && !current.is_empty() {
            let what = current.clone();
            let rx2 = &rx;
            // Spin until the next message.
            let mut n = 0;
            loop {
                match rx2.recv_timeout(Duration::from_millis(100)) {
                    Ok(m) => {
                        print!("\r\x1b[K");
                        break Some(m);
                    }
                    Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {
                        let mut out = std::io::stdout();
                        print!("\r\x1b[K  ");
                        let _ = print_line(&mut out, vec![colored(SPIN[n % SPIN.len()], ACC), plain(" "), plain(what.clone())], 200);
                        let _ = out.flush();
                        n += 1;
                    }
                    Err(_) => break None,
                }
            }
        } else {
            rx.recv().ok()
        };
        let Some(m) = m else { break };
        match m {
            Msg::Progress(i, Mark::Run, _) => current = steps.get(i).cloned().unwrap_or_default(),
            Msg::Progress(i, mark, note) if mark != Mark::Wait => {
                current.clear();
                failed |= mark == Mark::Fail;
                let (icon, c) = match mark {
                    Mark::Ok => ("✓ ", GOOD),
                    Mark::Warn => ("! ", WARN),
                    _ => ("✗ ", BAD),
                };
                say(vec![plain("  "), colored(icon, c), plain(steps.get(i).cloned().unwrap_or_default())]);
                if !note.is_empty() {
                    say(vec![plain("    "), if mark == Mark::Ok { dim(note) } else { colored(note, c) }]);
                }
            }
            Msg::Finished(tips) => {
                say(vec![]);
                for t in tips {
                    match t.split_once('\t') {
                        Some((k, v)) => say(vec![plain("  "), dim(format!("{k}{}", " ".repeat(10usize.saturating_sub(k.width())))), colored(v.to_string(), ACC)]),
                        None => say(vec![plain("  "), plain(t)]),
                    }
                }
                say(vec![]);
                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 };
        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_screen_fits_a_narrow_terminal() {
        let mut w = Wiz::new(Role::Hands);
        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() }];
        w.error = "配對碼不對，或已經過期（10 分鐘內有效，只能用一次）".into();
        for step in [Step::Form, Step::Brain, Step::Install, Step::Done] {
            w.step = step;
            for pw in [false, true] {
                w.password = pw;
                for l in w.body(40) {
                    assert!(width(&clip(l, 40)) <= 40);
                }
            }
        }
    }

    #[test]
    fn a_pasted_line_fills_the_form() {
        let mut w = Wiz::new(Role::Hands);
        w.focus = 0;
        w.url.clear();
        w.type_text("anybot setup https://anybot.example.com 482913");
        assert_eq!((w.url.as_str(), w.code.as_str()), ("https://anybot.example.com", "482913"));
        let mut w = Wiz::new(Role::Hands);
        w.focus = 0;
        w.url.clear();
        w.type_text(&crate::remote::pair_line("https://anybot.example.com/", "135790"));
        assert_eq!((w.url.as_str(), w.code.as_str()), ("https://anybot.example.com", "135790"));
    }
}