use std::io;
use std::sync::Arc;

use ratatui::crossterm::event::{self, Event, KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
use ratatui::layout::{Constraint, Layout, Rect};
use ratatui::style::{Color, Modifier, Style};
use ratatui::widgets::{Block, Borders, Clear, List, ListItem, ListState, Paragraph, Wrap};
use ratatui::{DefaultTerminal, Frame};

use crate::node::Node;
use crate::qr::{self, QrPayload};
use crate::store::{Friend, FriendProfile};

const C_ACCENT: Color = Color::Rgb(232, 165, 75);
const C_TEXT: Color = Color::Rgb(196, 214, 176);
const C_DIM: Color = Color::Rgb(98, 110, 92);
const C_ALERT: Color = Color::Rgb(220, 80, 70);
const C_STALE: Color = Color::Rgb(210, 180, 80);
const C_HL_BG: Color = Color::Rgb(48, 42, 28);
const C_BORDER: Color = Color::Rgb(72, 84, 64);

pub fn fingerprint_mismatch_banner() -> &'static str {
    "fingerprint mismatch"
}

pub fn rotate_screen_text() -> &'static str {
    "Rotate onion address?\n\
Your identity key stays the same.\n\
Online friends get a signed location update.\n\
Offline friends CANNOT find you until they rescan your QR.\n\
Type ROTATE to confirm    Esc to cancel"
}

/// Full Main-screen wordmark. Every line is <= 80 ASCII characters.
pub fn wordmark_banner() -> &'static str {
    "\
  .-~~-.  .-~~-.  .-~~-.     ONIONWIRE\n\
 (  o   )(  o   )(  o   )    identity = pubkey  onion = locator\n\
  `-..-'  `-..-'  `-..-'     tor messenger  no server"
}

/// One-line fallback when the terminal is narrower than the wordmark.
pub fn compact_banner() -> &'static str {
    "ONIONWIRE (o) tor"
}

pub fn onion_glyph() -> &'static str {
    "\
  .-.\n\
 ( o )\n\
  '-'"
}

pub fn help_overlay_text() -> &'static str {
    "\
OnionWire keys\n\
\n\
  Tab / Shift-Tab   cycle roster, chat, composer\n\
  1 / 2 / 3         focus roster / chat / composer\n\
  j k  or  Up Down  move or scroll focused pane\n\
  g / G             jump to top / bottom\n\
  Enter             /wipe  /wipe-all  /profile  /who  /pay  /tip\n\
  Esc               close overlay, go back, clear composer\n\
  F2                share QR\n\
  F3                paste a friend QR\n\
  F4                rotate onion locator\n\
  F5                selected friend's profile (/who)\n\
  /profile          edit name, bio, Monero address\n\
  /pay <xmr> [memo] invoice to receive\n\
  /tip <xmr> [memo] pay selected friend\n\
  ?                 this help\n\
  Ctrl-Q            quit\n\
\n\
Esc closes this overlay"
}

pub fn who_overlay_text(fingerprint: &str, onion: &str, profile: Option<&FriendProfile>) -> String {
    match profile {
        None => format!(
            "friend profile\n\nfp     {fingerprint}\nonion  {onion}\n\nno profile yet\n\nEsc closes"
        ),
        Some(p) => {
            let name = if p.display_name.is_empty() {
                "(none)"
            } else {
                p.display_name.as_str()
            };
            let bio = if p.bio.is_empty() {
                "(none)"
            } else {
                p.bio.as_str()
            };
            let xmr = if p.xmr_addr.is_empty() {
                "(none)"
            } else {
                p.xmr_addr.as_str()
            };
            format!(
                "friend profile\n\nname   {name}\nbio    {bio}\nxmr    {xmr}\nfp     {fingerprint}\nonion  {onion}\n\nEsc closes"
            )
        }
    }
}

pub fn banner_for_width(width: u16) -> &'static str {
    let full = wordmark_banner();
    let max_line = full.lines().map(|l| l.chars().count()).max().unwrap_or(0);
    if (width as usize) >= max_line {
        full
    } else {
        compact_banner()
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Pane {
    Roster,
    Chat,
    Composer,
}

impl Pane {
    pub fn next(self) -> Self {
        match self {
            Self::Roster => Self::Chat,
            Self::Chat => Self::Composer,
            Self::Composer => Self::Roster,
        }
    }

    pub fn prev(self) -> Self {
        match self {
            Self::Roster => Self::Composer,
            Self::Chat => Self::Roster,
            Self::Composer => Self::Chat,
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum WipeKind {
    Messages,
    All,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum SlashCmd {
    Wipe(WipeKind),
    Profile,
    Who,
    Pay { atomic: String, memo: String },
    Tip { atomic: String, memo: String },
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ProfileDraft {
    pub display_name: String,
    pub bio: String,
    pub xmr_addr: String,
}

#[derive(Debug, Clone)]
pub struct ProfileEditor {
    name: String,
    bio: String,
    xmr: String,
    field: usize,
}

impl ProfileEditor {
    pub fn new(display_name: &str, bio: &str, xmr_addr: &str) -> Self {
        Self {
            name: display_name.to_string(),
            bio: bio.to_string(),
            xmr: xmr_addr.to_string(),
            field: 0,
        }
    }

    pub fn on_enter(&self) -> ProfileDraft {
        ProfileDraft {
            display_name: self.name.clone(),
            bio: self.bio.clone(),
            xmr_addr: self.xmr.clone(),
        }
    }

    pub fn on_tab(&mut self) {
        self.field = (self.field + 1) % 3;
    }

    pub fn on_backtab(&mut self) {
        self.field = (self.field + 2) % 3;
    }

    pub fn on_char(&mut self, c: char) {
        if c == '\n' {
            return;
        }
        self.field_mut().push(c);
    }

    pub fn on_backspace(&mut self) {
        self.field_mut().pop();
    }

    pub fn field(&self) -> usize {
        self.field
    }

    pub fn display_name(&self) -> &str {
        &self.name
    }

    pub fn bio(&self) -> &str {
        &self.bio
    }

    pub fn xmr_addr(&self) -> &str {
        &self.xmr
    }

    fn field_mut(&mut self) -> &mut String {
        match self.field {
            0 => &mut self.name,
            1 => &mut self.bio,
            _ => &mut self.xmr,
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum WipeDecision {
    Pending,
    Confirm,
    Cancel,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum AppExit {
    Quit,
    WipeAll,
}

pub fn parse_cmd(raw: &str) -> Option<SlashCmd> {
    let s = raw.trim();
    match s {
        "/wipe" => return Some(SlashCmd::Wipe(WipeKind::Messages)),
        "/wipe-all" => return Some(SlashCmd::Wipe(WipeKind::All)),
        "/profile" => return Some(SlashCmd::Profile),
        "/who" => return Some(SlashCmd::Who),
        _ => {}
    }
    if let Some(rest) = s.strip_prefix("/pay")
        && (rest.is_empty() || rest.starts_with(char::is_whitespace))
    {
        return parse_amount_cmd(rest).map(|(atomic, memo)| SlashCmd::Pay { atomic, memo });
    }
    if let Some(rest) = s.strip_prefix("/tip")
        && (rest.is_empty() || rest.starts_with(char::is_whitespace))
    {
        return parse_amount_cmd(rest).map(|(atomic, memo)| SlashCmd::Tip { atomic, memo });
    }
    None
}

fn parse_amount_cmd(rest: &str) -> Option<(String, String)> {
    let rest = rest.trim();
    if rest.is_empty() {
        return None;
    }
    let mut parts = rest.splitn(2, char::is_whitespace);
    let amount = parts.next()?.trim();
    let memo = parts.next().unwrap_or("").trim().to_string();
    let atomic = crate::pay::xmr_to_atomic(amount).ok()?;
    Some((atomic, memo))
}

pub fn parse_slash(raw: &str) -> Option<WipeKind> {
    match parse_cmd(raw) {
        Some(SlashCmd::Wipe(k)) => Some(k),
        _ => None,
    }
}

pub fn wipe_screen_text(kind: WipeKind) -> &'static str {
    match kind {
        WipeKind::Messages => {
            "Wipe message log?\n\
Identity key and friends stay.\n\
Type WIPE to confirm    Esc to cancel"
        }
        WipeKind::All => {
            "Wipe ALL local data?\n\
This deletes your identity key. You become a new person.\n\
Type WIPEALL to confirm    Esc to cancel"
        }
    }
}

#[derive(Debug)]
pub struct WipePrompt {
    expected: &'static str,
    buf: String,
}

impl WipePrompt {
    pub fn messages() -> Self {
        Self {
            expected: "WIPE",
            buf: String::new(),
        }
    }

    pub fn all() -> Self {
        Self {
            expected: "WIPEALL",
            buf: String::new(),
        }
    }

    pub fn on_esc(&self) -> WipeDecision {
        WipeDecision::Cancel
    }

    pub fn on_char(&mut self, c: char) -> WipeDecision {
        if c == '\n' {
            return WipeDecision::Pending;
        }
        if c == '\u{8}' {
            self.buf.pop();
            return WipeDecision::Pending;
        }
        if !c.is_ascii_alphabetic() {
            return WipeDecision::Pending;
        }
        self.buf.push(c);
        if self.buf == self.expected {
            WipeDecision::Confirm
        } else {
            WipeDecision::Pending
        }
    }

    pub fn typed(&self) -> &str {
        &self.buf
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum RotateDecision {
    Pending,
    Confirm,
    Cancel,
}

#[derive(Debug, Default)]
pub struct RotatePrompt {
    buf: String,
}

impl RotatePrompt {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn on_esc(&self) -> RotateDecision {
        RotateDecision::Cancel
    }

    pub fn on_char(&mut self, c: char) -> RotateDecision {
        if c == '\n' {
            return RotateDecision::Pending;
        }
        if c == '\u{8}' {
            self.buf.pop();
            return RotateDecision::Pending;
        }
        if !c.is_ascii_alphabetic() {
            return RotateDecision::Pending;
        }
        self.buf.push(c);
        if self.buf == "ROTATE" {
            RotateDecision::Confirm
        } else {
            RotateDecision::Pending
        }
    }

    pub fn typed(&self) -> &str {
        &self.buf
    }
}

pub fn run(node: Arc<Node>, rt: tokio::runtime::Handle) -> Result<AppExit, String> {
    let mut app = App::new(node, rt)?;
    let mut terminal = ratatui::init();
    let result = app.run(&mut terminal);
    ratatui::restore();
    result
}

struct App {
    node: Arc<Node>,
    rt: tokio::runtime::Handle,
    screen: Screen,
    friends: Vec<Friend>,
    selected: usize,
    me_fp: String,
    me_onion: String,
    alert: Option<String>,
    status_note: Option<String>,
    composer: String,
    focus: Pane,
    help_open: bool,
    who_open: bool,
    chat_scroll: u16,
}

enum Screen {
    Main,
    Share { art: String, payload: String },
    Paste { buf: String, err: Option<String> },
    Approve { payload: QrPayload },
    Rotate { prompt: RotatePrompt },
    Wipe { kind: WipeKind, prompt: WipePrompt },
    Profile { editor: ProfileEditor },
}

impl App {
    fn new(node: Arc<Node>, rt: tokio::runtime::Handle) -> Result<Self, String> {
        let friends = node.list_friends()?;
        Ok(Self {
            me_fp: to_hex(&node.identity_pk()),
            me_onion: node.onion(),
            node,
            rt,
            screen: Screen::Main,
            friends,
            selected: 0,
            alert: None,
            status_note: None,
            composer: String::new(),
            focus: Pane::Composer,
            help_open: false,
            who_open: false,
            chat_scroll: 0,
        })
    }

    fn run(&mut self, terminal: &mut DefaultTerminal) -> Result<AppExit, String> {
        loop {
            terminal.draw(|f| self.draw(f)).map_err(|e| e.to_string())?;
            let Event::Key(key) = event::read().map_err(io_err)? else {
                continue;
            };
            if key.kind != KeyEventKind::Press {
                continue;
            }
            if key.code == KeyCode::Char('q') && key.modifiers.contains(KeyModifiers::CONTROL) {
                return Ok(AppExit::Quit);
            }
            if let Some(exit) = self.handle_key(key)? {
                return Ok(exit);
            }
        }
    }

    fn handle_key(&mut self, key: KeyEvent) -> Result<Option<AppExit>, String> {
        if self.help_open {
            match key.code {
                KeyCode::Esc | KeyCode::Char('?') => self.help_open = false,
                _ => {}
            }
            return Ok(None);
        }
        if self.who_open {
            match key.code {
                KeyCode::Esc | KeyCode::F(5) => self.who_open = false,
                KeyCode::Char('?') => {
                    self.who_open = false;
                    self.help_open = true;
                }
                _ => {}
            }
            return Ok(None);
        }
        if key.code == KeyCode::Char('?') && !matches!(self.screen, Screen::Paste { .. }) {
            self.help_open = true;
            return Ok(None);
        }

        let mut wipe_confirm = None;
        let mut profile_save = None;
        let mut open_profile = false;
        let mut pay_cmd = None;
        let mut tip_cmd = None;
        match &mut self.screen {
            Screen::Main => match key.code {
                KeyCode::Tab => self.focus = self.focus.next(),
                KeyCode::BackTab => self.focus = self.focus.prev(),
                KeyCode::Up => self.nav_up(),
                KeyCode::Down => self.nav_down(),
                KeyCode::F(2) => self.open_share()?,
                KeyCode::F(3) => {
                    self.screen = Screen::Paste {
                        buf: String::new(),
                        err: None,
                    };
                }
                KeyCode::F(4) => {
                    self.screen = Screen::Rotate {
                        prompt: RotatePrompt::new(),
                    };
                }
                KeyCode::F(5) => self.who_open = true,
                KeyCode::Esc => self.composer.clear(),
                KeyCode::Backspace => {
                    if self.focus == Pane::Composer {
                        self.composer.pop();
                    }
                }
                KeyCode::Enter => match parse_cmd(&self.composer) {
                    Some(SlashCmd::Wipe(kind)) => {
                        self.composer.clear();
                        let prompt = match kind {
                            WipeKind::Messages => WipePrompt::messages(),
                            WipeKind::All => WipePrompt::all(),
                        };
                        self.screen = Screen::Wipe { kind, prompt };
                    }
                    Some(SlashCmd::Profile) => {
                        self.composer.clear();
                        open_profile = true;
                    }
                    Some(SlashCmd::Who) => {
                        self.composer.clear();
                        self.who_open = true;
                    }
                    Some(SlashCmd::Pay { atomic, memo }) => {
                        self.composer.clear();
                        pay_cmd = Some((atomic, memo));
                    }
                    Some(SlashCmd::Tip { atomic, memo }) => {
                        self.composer.clear();
                        tip_cmd = Some((atomic, memo));
                    }
                    None => {}
                },
                KeyCode::Char(c) if !key.modifiers.contains(KeyModifiers::CONTROL) => {
                    self.handle_main_char(c);
                }
                _ => {}
            },
            Screen::Share { .. } => {
                if key.code == KeyCode::Esc {
                    self.screen = Screen::Main;
                }
            }
            Screen::Paste { buf, err } => match key.code {
                KeyCode::Esc => self.screen = Screen::Main,
                KeyCode::Enter => {
                    let raw = buf.clone();
                    self.submit_paste(&raw)?;
                }
                KeyCode::Backspace => {
                    buf.pop();
                    *err = None;
                }
                KeyCode::Char(c) if !key.modifiers.contains(KeyModifiers::CONTROL) => {
                    buf.push(c);
                    *err = None;
                }
                _ => {}
            },
            Screen::Approve { payload } => match key.code {
                KeyCode::Char('y') | KeyCode::Enter => {
                    let p = payload.clone();
                    self.accept_friend(&p)?;
                }
                KeyCode::Char('n') | KeyCode::Esc => self.screen = Screen::Main,
                _ => {}
            },
            Screen::Rotate { prompt } => match key.code {
                KeyCode::Esc => self.screen = Screen::Main,
                KeyCode::Char(c) if !key.modifiers.contains(KeyModifiers::CONTROL) => {
                    if prompt.on_char(c) == RotateDecision::Confirm {
                        self.confirm_rotate()?;
                    }
                }
                KeyCode::Backspace => {
                    prompt.on_char('\u{8}');
                }
                _ => {}
            },
            Screen::Wipe { kind, prompt } => {
                let kind = *kind;
                match key.code {
                    KeyCode::Esc => self.screen = Screen::Main,
                    KeyCode::Char(c) if !key.modifiers.contains(KeyModifiers::CONTROL) => {
                        if prompt.on_char(c) == WipeDecision::Confirm {
                            wipe_confirm = Some(kind);
                        }
                    }
                    KeyCode::Backspace => {
                        prompt.on_char('\u{8}');
                    }
                    _ => {}
                }
            }
            Screen::Profile { editor } => match key.code {
                KeyCode::Esc => self.screen = Screen::Main,
                KeyCode::Tab => editor.on_tab(),
                KeyCode::BackTab => editor.on_backtab(),
                KeyCode::Backspace => editor.on_backspace(),
                KeyCode::Enter => profile_save = Some(editor.on_enter()),
                KeyCode::Char(c) if !key.modifiers.contains(KeyModifiers::CONTROL) => {
                    editor.on_char(c);
                }
                _ => {}
            },
        }
        if let Some(kind) = wipe_confirm {
            return self.confirm_wipe(kind);
        }
        if open_profile {
            self.open_profile()?;
        }
        if let Some(draft) = profile_save {
            self.save_profile(draft)?;
        }
        if let Some((atomic, memo)) = pay_cmd {
            self.send_pay(&atomic, &memo)?;
        }
        if let Some((atomic, memo)) = tip_cmd {
            self.send_tip(&atomic, &memo)?;
        }
        Ok(None)
    }

    fn handle_main_char(&mut self, c: char) {
        if self.focus != Pane::Composer {
            match c {
                '1' => self.focus = Pane::Roster,
                '2' => self.focus = Pane::Chat,
                '3' => self.focus = Pane::Composer,
                'j' => self.nav_down(),
                'k' => self.nav_up(),
                'g' => self.nav_top(),
                'G' => self.nav_bottom(),
                _ => {}
            }
            return;
        }
        self.composer.push(c);
    }

    fn nav_up(&mut self) {
        match self.focus {
            Pane::Roster => {
                self.selected = self.selected.saturating_sub(1);
                self.chat_scroll = u16::MAX;
            }
            Pane::Chat => {
                self.chat_scroll = self.chat_scroll.saturating_sub(1);
            }
            Pane::Composer => {}
        }
    }

    fn nav_down(&mut self) {
        match self.focus {
            Pane::Roster => {
                if !self.friends.is_empty() {
                    self.selected = (self.selected + 1).min(self.friends.len() - 1);
                    self.chat_scroll = u16::MAX;
                }
            }
            Pane::Chat => {
                self.chat_scroll = self.chat_scroll.saturating_add(1);
            }
            Pane::Composer => {}
        }
    }

    fn nav_top(&mut self) {
        match self.focus {
            Pane::Roster => {
                self.selected = 0;
                self.chat_scroll = u16::MAX;
            }
            Pane::Chat => self.chat_scroll = 0,
            Pane::Composer => {}
        }
    }

    fn nav_bottom(&mut self) {
        match self.focus {
            Pane::Roster => {
                if !self.friends.is_empty() {
                    self.selected = self.friends.len() - 1;
                    self.chat_scroll = u16::MAX;
                }
            }
            Pane::Chat => self.chat_scroll = u16::MAX,
            Pane::Composer => {}
        }
    }

    fn confirm_wipe(&mut self, kind: WipeKind) -> Result<Option<AppExit>, String> {
        match kind {
            WipeKind::Messages => {
                self.node.wipe_messages()?;
                self.status_note = Some("wiped messages".into());
                self.screen = Screen::Main;
                Ok(None)
            }
            WipeKind::All => Ok(Some(AppExit::WipeAll)),
        }
    }

    fn confirm_rotate(&mut self) -> Result<(), String> {
        let node = Arc::clone(&self.node);
        match self.rt.block_on(node.rotate()) {
            Ok(outcome) => {
                self.me_onion = node.onion();
                self.status_note = Some(format!(
                    "rotated · notified {}/{} friends",
                    outcome.notified, outcome.friends
                ));
                self.open_share()
            }
            Err(e) => {
                self.alert = Some(e);
                self.screen = Screen::Main;
                Ok(())
            }
        }
    }

    fn open_share(&mut self) -> Result<(), String> {
        let payload = self.node.qr_payload()?;
        let art = qr::render_unicode(&payload).map_err(|e| e.to_string())?;
        self.screen = Screen::Share { art, payload };
        Ok(())
    }

    fn submit_paste(&mut self, raw: &str) -> Result<(), String> {
        match qr::decode(raw.trim()) {
            Err(e) => {
                self.screen = Screen::Paste {
                    buf: raw.to_string(),
                    err: Some(e.to_string()),
                };
            }
            Ok(payload) => {
                let known = self.node.get_friend(&payload.pubkey)?.is_some();
                if known {
                    self.accept_friend(&payload)?;
                } else {
                    self.screen = Screen::Approve { payload };
                }
            }
        }
        Ok(())
    }

    fn accept_friend(&mut self, payload: &QrPayload) -> Result<(), String> {
        self.node.add_friend_payload(payload)?;
        self.reload_friends()?;
        self.screen = Screen::Main;
        Ok(())
    }

    fn reload_friends(&mut self) -> Result<(), String> {
        self.friends = self.node.list_friends()?;
        if self.friends.is_empty() {
            self.selected = 0;
        } else {
            self.selected = self.selected.min(self.friends.len() - 1);
        }
        self.chat_scroll = u16::MAX;
        Ok(())
    }

    fn open_profile(&mut self) -> Result<(), String> {
        let p = self.node.self_profile()?;
        self.screen = Screen::Profile {
            editor: ProfileEditor::new(&p.display_name, &p.bio, &p.xmr_addr),
        };
        Ok(())
    }

    fn save_profile(&mut self, draft: ProfileDraft) -> Result<(), String> {
        if let Err(e) = self
            .node
            .set_self_profile(&draft.display_name, &draft.bio, &draft.xmr_addr)
        {
            self.alert = Some(e);
            return Ok(());
        }
        self.screen = Screen::Main;
        if let Some(friend) = self.friends.get(self.selected) {
            let pk = friend.pubkey.clone();
            match self.rt.block_on(self.node.push_self_profile(&pk)) {
                Ok(()) => self.status_note = Some("profile saved · sent".into()),
                Err(e) => self.status_note = Some(format!("profile send failed: {e}")),
            }
        } else {
            self.status_note = Some("profile saved".into());
        }
        Ok(())
    }

    fn send_pay(&mut self, atomic: &str, memo: &str) -> Result<(), String> {
        let Some(friend) = self.friends.get(self.selected) else {
            self.status_note = Some("no friend selected".into());
            return Ok(());
        };
        let pk = friend.pubkey.clone();
        match self.rt.block_on(self.node.pay_invoice(&pk, atomic, memo)) {
            Ok(()) => self.status_note = Some("invoice sent".into()),
            Err(e) => self.status_note = Some(e),
        }
        Ok(())
    }

    fn send_tip(&mut self, atomic: &str, memo: &str) -> Result<(), String> {
        let Some(friend) = self.friends.get(self.selected) else {
            self.status_note = Some("no friend selected".into());
            return Ok(());
        };
        let pk = friend.pubkey.clone();
        match self.rt.block_on(self.node.tip(&pk, atomic, memo)) {
            Ok(()) => self.status_note = Some("tip sent".into()),
            Err(e) => self.status_note = Some(e),
        }
        Ok(())
    }

    fn who_body(&self) -> String {
        let Some(friend) = self.friends.get(self.selected) else {
            return "no friend selected\n\nEsc closes".into();
        };
        let profile = self.node.friend_profile(&friend.pubkey).ok().flatten();
        who_overlay_text(&friend.fingerprint, &friend.onion, profile.as_ref())
    }

    fn draw(&self, f: &mut Frame) {
        match &self.screen {
            Screen::Main => self.draw_main(f),
            Screen::Share { art, payload } => draw_share(f, art, payload),
            Screen::Paste { buf, err } => draw_paste(f, buf, err.as_deref()),
            Screen::Approve { payload } => draw_approve(f, payload),
            Screen::Rotate { prompt } => draw_rotate(f, prompt.typed()),
            Screen::Wipe { kind, prompt } => draw_wipe(f, *kind, prompt.typed()),
            Screen::Profile { editor } => draw_profile(f, editor),
        }
        if self.help_open {
            draw_text_overlay(f, "? help", help_overlay_text());
        } else if self.who_open {
            draw_text_overlay(f, "/who", &self.who_body());
        }
    }

    fn draw_main(&self, f: &mut Frame) {
        let area = f.area();
        let banner = banner_for_width(area.width);
        let banner_h = banner.lines().count() as u16;
        let alert_h = u16::from(self.alert.is_some());
        let cols = Layout::vertical([
            Constraint::Length(banner_h),
            Constraint::Length(alert_h),
            Constraint::Min(3),
            Constraint::Length(3),
            Constraint::Length(1),
        ])
        .split(area);

        f.render_widget(
            Paragraph::new(banner).style(Style::default().fg(C_ACCENT)),
            cols[0],
        );
        if let Some(msg) = &self.alert {
            f.render_widget(
                Paragraph::new(msg.as_str()).style(Style::default().fg(C_ALERT)),
                cols[1],
            );
        }

        let panes =
            Layout::horizontal([Constraint::Percentage(36), Constraint::Min(10)]).split(cols[2]);

        let stale_n = self.friends.iter().filter(|fr| !fr.last_connect_ok).count();
        let roster_title = if stale_n > 0 {
            format!("roster {}  {stale_n} stale", self.friends.len())
        } else {
            format!("roster {}", self.friends.len())
        };

        let items: Vec<ListItem> = self
            .friends
            .iter()
            .map(|friend| {
                let name = friend.petname.as_deref().unwrap_or(&friend.fingerprint);
                let fp = truncate_fp(&friend.fingerprint);
                let mut line = format!("{name}  {fp}");
                if !friend.last_connect_ok {
                    line.push_str(" stale");
                }
                let style = if friend.last_connect_ok {
                    Style::default().fg(C_TEXT)
                } else {
                    Style::default().fg(C_STALE)
                };
                ListItem::new(line).style(style)
            })
            .collect();
        let roster = List::new(items)
            .highlight_style(
                Style::default()
                    .bg(C_HL_BG)
                    .fg(C_ACCENT)
                    .add_modifier(Modifier::BOLD),
            )
            .highlight_symbol("> ")
            .block(self.pane_block(&roster_title, Pane::Roster));
        let mut roster_state = ListState::default();
        if !self.friends.is_empty() {
            roster_state.select(Some(self.selected));
        }
        f.render_stateful_widget(roster, panes[0], &mut roster_state);

        let chat_lines = self.chat_lines();
        let inner_h = panes[1].height.saturating_sub(2);
        let nlines = chat_lines.len();
        let max_scroll = nlines.saturating_sub(inner_h as usize) as u16;
        let scroll = self.chat_scroll.min(max_scroll);
        let overflow = nlines > inner_h as usize && inner_h > 0;
        let chat_title = {
            let name = self.friends.get(self.selected).map(|friend| {
                friend
                    .petname
                    .as_deref()
                    .unwrap_or(&friend.fingerprint)
                    .to_string()
            });
            let mut t = match name {
                Some(n) => format!("chat  {n}"),
                None => "chat".to_string(),
            };
            if overflow {
                let end = (scroll as usize + inner_h as usize).min(nlines);
                t.push_str(&format!("  {}-{end}/{nlines}", scroll as usize + 1));
            }
            t
        };
        let chat_text = chat_lines.join("\n");
        let chat = Paragraph::new(chat_text)
            .style(Style::default().fg(C_TEXT))
            .wrap(Wrap { trim: false })
            .scroll((scroll, 0))
            .block(self.pane_block(&chat_title, Pane::Chat));
        f.render_widget(chat, panes[1]);

        let cmd = if self.composer.is_empty() {
            "/wipe  /wipe-all  /profile  /who  /pay  /tip".to_string()
        } else {
            self.composer.clone()
        };
        let cmd_style = if self.composer.is_empty() {
            Style::default().fg(C_DIM)
        } else {
            Style::default().fg(C_TEXT)
        };
        f.render_widget(
            Paragraph::new(cmd)
                .style(cmd_style)
                .block(self.pane_block("composer", Pane::Composer)),
            cols[3],
        );

        let footer = self.footer_line(area.width);
        f.render_widget(
            Paragraph::new(footer).style(Style::default().fg(C_DIM)),
            cols[4],
        );
    }

    fn footer_line(&self, width: u16) -> String {
        status_footer(
            width,
            &self.me_fp,
            &self.me_onion,
            self.status_note.as_deref(),
            footer_hints(&self.screen),
        )
    }

    fn chat_lines(&self) -> Vec<String> {
        let Some(friend) = self.friends.get(self.selected) else {
            return vec!["no friends yet".into(), "F3 paste a QR to add one".into()];
        };
        match self.node.list_messages(&friend.pubkey) {
            Ok(msgs) if msgs.is_empty() => vec!["no messages".into()],
            Ok(msgs) => msgs
                .iter()
                .map(|m| {
                    let side = if m.dir == "out" { "you" } else { "them" };
                    format!("{side}: {}", String::from_utf8_lossy(&m.plaintext))
                })
                .collect(),
            Err(e) => vec![e],
        }
    }

    fn pane_block<'a>(&self, title: &'a str, pane: Pane) -> Block<'a> {
        let focused = self.focus == pane;
        let border = if focused { C_ACCENT } else { C_BORDER };
        let title_style = if focused {
            Style::default().fg(C_ACCENT).add_modifier(Modifier::BOLD)
        } else {
            Style::default().fg(C_DIM)
        };
        Block::default()
            .borders(Borders::ALL)
            .border_style(Style::default().fg(border))
            .title(title)
            .title_style(title_style)
    }
}

/// Status bar: TOR + identity, then as many hints as fit, always ending with `? help`.
pub fn status_footer(
    width: u16,
    me_fp: &str,
    me_onion: &str,
    status_note: Option<&str>,
    hints: &str,
) -> String {
    let w = width as usize;
    let onion = if me_onion.is_empty() {
        "unset".to_string()
    } else if width >= 110 {
        me_onion.to_string()
    } else {
        truncate_fp(me_onion)
    };
    let ident = format!("TOR  me:{}  onion:{onion}", truncate_fp(me_fp));
    let note = status_note.unwrap_or("").trim();
    let extra = hints.replace("? help", "");
    let extra = extra.split_whitespace().collect::<Vec<_>>().join(" ");
    let help = "? help";
    let candidates = [
        join_footer(&[note, ident.as_str(), extra.as_str(), help]),
        join_footer(&[ident.as_str(), extra.as_str(), help]),
        join_footer(&[note, ident.as_str(), help]),
        join_footer(&[ident.as_str(), help]),
    ];
    for line in candidates {
        if line.chars().count() <= w {
            return line;
        }
    }
    let suffix = format!("  {help}");
    let budget = w.saturating_sub(suffix.chars().count());
    let head: String = ident.chars().take(budget).collect();
    format!("{head}{suffix}")
}

fn join_footer(parts: &[&str]) -> String {
    parts
        .iter()
        .map(|p| p.trim())
        .filter(|p| !p.is_empty())
        .collect::<Vec<_>>()
        .join("  ")
}

/// Main-screen key hints. Kept short so width 80 still shows TOR + identity + `? help`.
pub fn main_footer_hints() -> &'static str {
    "Tab  F2  F3  F4  F5  ? help  Ctrl-Q"
}

fn footer_hints(screen: &Screen) -> &'static str {
    match screen {
        Screen::Main => main_footer_hints(),
        Screen::Share { .. } => "Esc back  ? help",
        Screen::Paste { .. } => "Enter submit  Esc back  ? help",
        Screen::Approve { .. } => "y accept  n reject  ? help",
        Screen::Rotate { .. } => "type ROTATE  Esc cancel  ? help",
        Screen::Wipe { kind, .. } => match kind {
            WipeKind::Messages => "type WIPE  Esc cancel  ? help",
            WipeKind::All => "type WIPEALL  Esc cancel  ? help",
        },
        Screen::Profile { .. } => "Enter save  Tab field  Esc cancel  ? help",
    }
}

fn themed_block(title: &str) -> Block<'_> {
    Block::default()
        .borders(Borders::ALL)
        .border_style(Style::default().fg(C_ACCENT))
        .title(title)
        .title_style(Style::default().fg(C_ACCENT).add_modifier(Modifier::BOLD))
}

fn draw_share(f: &mut Frame, art: &str, payload: &str) {
    let glyph = onion_glyph();
    let body = format!("{glyph}\n\n{art}\n{payload}\n\nEsc back");
    f.render_widget(
        Paragraph::new(body)
            .style(Style::default().fg(C_TEXT))
            .wrap(Wrap { trim: false })
            .block(themed_block("(o) share")),
        f.area(),
    );
}

fn draw_paste(f: &mut Frame, buf: &str, err: Option<&str>) {
    let hint = err.unwrap_or("paste onionwire:v1 payload, Enter to submit");
    let body = format!("{hint}\n\n{buf}");
    let style = if err.is_some() {
        Style::default().fg(C_ALERT)
    } else {
        Style::default().fg(C_TEXT)
    };
    f.render_widget(
        Paragraph::new(body)
            .style(style)
            .wrap(Wrap { trim: false })
            .block(themed_block("(o) paste QR")),
        f.area(),
    );
}

fn draw_approve(f: &mut Frame, payload: &QrPayload) {
    let fp = to_hex(&payload.pubkey);
    let body = format!(
        "Unknown key. Add this friend?\n\nfp  {}\nonion  {}\n\ny accept   n / Esc reject",
        truncate_fp(&fp),
        payload.onion
    );
    f.render_widget(
        Paragraph::new(body)
            .style(Style::default().fg(C_TEXT))
            .block(themed_block("(o) approve")),
        f.area(),
    );
}

fn draw_rotate(f: &mut Frame, typed: &str) {
    let body = format!("{}\n\n{typed}", rotate_screen_text());
    f.render_widget(
        Paragraph::new(body)
            .style(Style::default().fg(C_TEXT))
            .wrap(Wrap { trim: false })
            .block(themed_block("(o) rotate locator")),
        f.area(),
    );
}

fn draw_wipe(f: &mut Frame, kind: WipeKind, typed: &str) {
    let title = match kind {
        WipeKind::Messages => "(o) wipe",
        WipeKind::All => "(o) wipe all",
    };
    let body = format!("{}\n\n{typed}", wipe_screen_text(kind));
    f.render_widget(
        Paragraph::new(body)
            .style(Style::default().fg(C_TEXT))
            .wrap(Wrap { trim: false })
            .block(themed_block(title)),
        f.area(),
    );
}

fn draw_profile(f: &mut Frame, editor: &ProfileEditor) {
    let labels = ["name", "bio", "xmr"];
    let values = [editor.display_name(), editor.bio(), editor.xmr_addr()];
    let mut body = String::from(
        "Your profile (friend-visible)\nEnter saves    Esc cancels    Tab next field\n",
    );
    for (i, (label, value)) in labels.iter().zip(values).enumerate() {
        let mark = if editor.field() == i { ">" } else { " " };
        body.push_str(&format!("\n{mark} {label}: {value}"));
    }
    f.render_widget(
        Paragraph::new(body)
            .style(Style::default().fg(C_TEXT))
            .wrap(Wrap { trim: false })
            .block(themed_block("(o) profile")),
        f.area(),
    );
}

fn draw_text_overlay(f: &mut Frame, title: &str, text: &str) {
    let area = f.area();
    let lines = text.lines().count() as u16 + 2;
    let text_w = text
        .lines()
        .map(|l| l.chars().count() as u16)
        .max()
        .unwrap_or(40)
        .saturating_add(4);
    let width = text_w.min(area.width.saturating_sub(2)).max(10);
    let height = lines.min(area.height.saturating_sub(2)).max(3);
    let popup = Rect {
        x: area.x + (area.width.saturating_sub(width)) / 2,
        y: area.y + (area.height.saturating_sub(height)) / 2,
        width,
        height,
    };
    f.render_widget(Clear, popup);
    f.render_widget(
        Paragraph::new(text)
            .style(Style::default().fg(C_TEXT))
            .block(themed_block(title)),
        popup,
    );
}

fn truncate_fp(fp: &str) -> String {
    let s: String = fp.chars().take(8).collect();
    format!("{s}…")
}

fn to_hex(bytes: &[u8]) -> String {
    bytes.iter().map(|b| format!("{b:02x}")).collect()
}

fn io_err(e: io::Error) -> String {
    e.to_string()
}