simplemailclient 0.2.3

//! Split-pane TUI:
//!   Left sidebar  – folder list (Inbox / Sent / Starred / Trash) + contact list
//!   Right top     – message list for selected folder
//!   Right bottom  – message reading pane
//!
//! Keybinds come from config (defaults: q quit, c compose, r reply, d delete,
//! s star, S sync, Tab/BackTab cycle folders, j/k navigate, Enter open).

use std::env;
use std::io;
use std::time::{Duration, Instant};
use anyhow::Result;
use base64::Engine;
use crossterm::{
    event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyEventKind, KeyModifiers},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use ratatui::{
    backend::CrosstermBackend,
    layout::{Constraint, Direction, Layout, Rect},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, Clear, List, ListItem, ListState, Paragraph, Wrap},
    Frame, Terminal,
};
use crate::config::Config;
use crate::store::{Attachment, Folder, MailStore, Message};
use crate::transport;

// ─── State ────────────────────────────────────────────────────────────────────

const FOLDERS: [Folder; 4] = [Folder::Inbox, Folder::Sent, Folder::Starred, Folder::Trash];

#[derive(Debug, Clone, Copy, PartialEq)]
enum Focus {
    Folders,
    /// The contacts panel (visible only when show_contacts is true).
    Contacts,
    Messages,
    Reading,
}

/// Which field is active inside the "Add contact" overlay.
#[derive(Debug, Clone, Copy, PartialEq)]
enum AddContactField {
    Address,
    Nickname,
}

#[derive(Debug, Clone, Copy, PartialEq)]
enum ComposeField {
    To,
    Attach,
    Body,
}

#[derive(Debug, Clone)]
enum Mode {
    Normal,
    /// Compose / reply modal. Carries the recipient, body, and queued
    /// attachment file paths so nothing is lost when switching fields.
    Compose {
        to: String,
        body: String,
        /// Paths of files queued as attachments.
        attachments: Vec<String>,
        /// Current text in the attachment-path input field.
        attach_input: String,
        field: ComposeField,
    },
    /// Full-screen overlay showing a decoded text attachment.
    ViewAttachment {
        filename: String,
        /// Decoded UTF-8 content of the file.
        content: String,
        /// Vertical scroll offset (lines from top).
        scroll: u16,
    },
    /// Overlay for manually adding a new contact.
    AddContact {
        address: String,
        nickname: String,
        field: AddContactField,
    },
    /// Overlay for editing an existing contact's nickname.
    SetNickname {
        /// Address of the contact being edited.
        address: String,
        /// Current text in the nickname input.
        nickname: String,
    },
}

/// What the compose modal wants the main loop to do once the borrow on
/// `state.mode` is released (so async send can run outside the borrow).
enum ComposeAction {
    None,
    /// Set the status line (e.g. attachment feedback) without leaving compose.
    Notice(String),
    Abort,
    Send {
        to: String,
        body: String,
        attachments: Vec<String>,
    },
}

/// Actions produced by the AddContact / SetNickname overlays.
enum ContactAction {
    None,
    Abort,
    AddContact { address: String, nickname: String },
    SetNickname { address: String, nickname: String },
}

struct AppState<'a> {
    cfg: &'a Config,
    store: &'a MailStore,
    folder_idx: usize,
    msg_list_state: ListState,
    messages: Vec<(usize, Message)>, // (store_index, message)
    reading: Option<Message>,
    status: String,
    show_contacts: bool,
    focus: Focus,
    mode: Mode,
    /// Index of the currently selected attachment in the reading pane (0-based).
    selected_attachment: usize,
    /// Index of the selected contact in the contacts panel (0-based into all_contacts()).
    contact_selected: usize,
}

impl<'a> AppState<'a> {
    fn new(cfg: &'a Config, store: &'a MailStore) -> Self {
        let mut s = Self {
            cfg,
            store,
            folder_idx: 0,
            msg_list_state: ListState::default(),
            messages: vec![],
            reading: None,
            status: format!(" mailrs  •  {}", cfg.identity),
            show_contacts: false,
            focus: Focus::Messages,
            mode: Mode::Normal,
            selected_attachment: 0,
            contact_selected: 0,
        };
        s.reload_messages();
        s
    }

    fn current_folder(&self) -> &Folder {
        &FOLDERS[self.folder_idx]
    }

    fn reload_messages(&mut self) {
        self.messages = self.store.messages_in(self.current_folder());
        self.messages.reverse(); // newest first
        if self.messages.is_empty() {
            self.msg_list_state.select(None);
        } else {
            let sel = self.msg_list_state.selected().unwrap_or(0);
            self.msg_list_state.select(Some(sel.min(self.messages.len() - 1)));
        }
        self.reading = self.selected_message();
        self.selected_attachment = 0;
    }

    fn selected_message(&self) -> Option<Message> {
        let i = self.msg_list_state.selected()?;
        self.messages.get(i).map(|(_, m)| m.clone())
    }

    fn selected_store_index(&self) -> Option<usize> {
        let i = self.msg_list_state.selected()?;
        self.messages.get(i).map(|(idx, _)| *idx)
    }

    fn next_msg(&mut self) {
        if self.messages.is_empty() { return; }
        let i = self.msg_list_state.selected().unwrap_or(0);
        let next = (i + 1).min(self.messages.len() - 1);
        self.msg_list_state.select(Some(next));
        self.open_selected();
    }

    fn prev_msg(&mut self) {
        if self.messages.is_empty() { return; }
        let i = self.msg_list_state.selected().unwrap_or(0);
        let prev = i.saturating_sub(1);
        self.msg_list_state.select(Some(prev));
        self.open_selected();
    }

    fn open_selected(&mut self) {
        if let Some(idx) = self.selected_store_index() {
            self.store.mark_read(idx).ok();
        }
        self.reading = self.selected_message();
        self.selected_attachment = 0;
        if let Some(ref mut m) = self.reading {
            m.read = true;
        }
    }

    fn next_folder(&mut self) {
        self.folder_idx = (self.folder_idx + 1) % FOLDERS.len();
        self.msg_list_state.select(None);
        self.reading = None;
        self.reload_messages();
    }

    fn prev_folder(&mut self) {
        self.folder_idx = (self.folder_idx + FOLDERS.len() - 1) % FOLDERS.len();
        self.msg_list_state.select(None);
        self.reading = None;
        self.reload_messages();
    }
}

// ─── Entry point ─────────────────────────────────────────────────────────────

pub async fn run(cfg: &Config, store: &MailStore) -> Result<()> {
    enable_raw_mode()?;
    let mut stdout = io::stdout();
    execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    let result = run_loop(cfg, store, &mut terminal).await;

    disable_raw_mode()?;
    execute!(terminal.backend_mut(), LeaveAlternateScreen, DisableMouseCapture)?;
    terminal.show_cursor()?;

    result
}

async fn run_loop<B: ratatui::backend::Backend + io::Write>(
    cfg: &Config,
    store: &MailStore,
    terminal: &mut Terminal<B>,
) -> Result<()> {
    let mut state = AppState::new(cfg, store);
    let kb = &cfg.keybinds;

    // Auto-sync every 10 seconds while idle.
    const AUTO_SYNC_INTERVAL: Duration = Duration::from_secs(10);
    let mut last_sync = Instant::now();

    loop {
        terminal.draw(|f| draw(f, &mut state))?;

        // ── Auto-sync ────────────────────────────────────────────────────────
        // Fire only when idle in Normal mode so it never interrupts composing.
        if matches!(state.mode, Mode::Normal) && last_sync.elapsed() >= AUTO_SYNC_INTERVAL {
            let unread_before = store.unread_count();
            match transport::fetch_imap(cfg, store).await {
                Ok(_) => {
                    state.reload_messages();
                    let unread_after = store.unread_count();
                    if unread_after > unread_before {
                        bell();
                    }
                    state.status = format!(" Auto-synced · {} unread", unread_after);
                }
                Err(e) => state.status = format!(" Auto-sync error: {}", e),
            }
            last_sync = Instant::now();
        }

        // Wait up to 200ms for input; the timeout lets the auto-sync timer tick
        // even when the user isn't pressing anything.
        if !event::poll(Duration::from_millis(200))? {
            continue;
        }

        if let Event::Key(key) = event::read()? {
            // On Windows, crossterm emits both Press and Release events.
            // Ignore everything except Press so each keystroke registers once.
            if key.kind != KeyEventKind::Press {
                continue;
            }

            // ── Compose / reply modal input ──────────────────────────────────
            // Compute an action while borrowing state.mode, then act on it
            // after the borrow is released (so the async send can run).
            let in_compose = matches!(state.mode, Mode::Compose { .. });
            if let Mode::Compose { to, body, attachments, attach_input, field } = &mut state.mode {
                let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
                let action = match key.code {
                    // Ctrl+S → send.
                    // Auto-commit any unsubmitted path sitting in attach_input
                    // so the user doesn't have to press Enter before Ctrl+S.
                    // If the path is invalid, block the send and report why.
                    KeyCode::Char('s') if ctrl => {
                        let pending = attach_input.trim().to_string();
                        let attach_err = if !pending.is_empty() {
                            validate_attachment(&pending).err()
                        } else {
                            None
                        };
                        if let Some(e) = attach_err {
                            ComposeAction::Notice(format!(
                                " ✗ Attachment: {} — fix or clear it first",
                                e
                            ))
                        } else {
                            // Commit the pending path (if any) then send
                            if !pending.is_empty() {
                                attachments.push(pending);
                                attach_input.clear();
                            }
                            ComposeAction::Send {
                                to: to.clone(),
                                body: body.clone(),
                                attachments: attachments.clone(),
                            }
                        }
                    }
                    KeyCode::Esc => ComposeAction::Abort,
                    // Tab flow: To → Body → Attach → Body.
                    // When leaving the Attach field, auto-commit any typed path.
                    // If the path is invalid, show the error and keep focus on Attach.
                    KeyCode::Tab | KeyCode::Down => {
                        let commit_err = if *field == ComposeField::Attach {
                            let p = attach_input.trim().to_string();
                            if p.is_empty() { None } else {
                                match validate_attachment(&p) {
                                    Ok(_) => { attachments.push(p); attach_input.clear(); None }
                                    Err(e) => Some(e),
                                }
                            }
                        } else { None };
                        if let Some(e) = commit_err {
                            ComposeAction::Notice(format!(" ✗ {}", e))
                        } else {
                            *field = match *field {
                                ComposeField::To     => ComposeField::Body,
                                ComposeField::Body   => ComposeField::Attach,
                                ComposeField::Attach => ComposeField::Body,
                            };
                            ComposeAction::None
                        }
                    }
                    KeyCode::BackTab | KeyCode::Up => {
                        let commit_err = if *field == ComposeField::Attach {
                            let p = attach_input.trim().to_string();
                            if p.is_empty() { None } else {
                                match validate_attachment(&p) {
                                    Ok(_) => { attachments.push(p); attach_input.clear(); None }
                                    Err(e) => Some(e),
                                }
                            }
                        } else { None };
                        if let Some(e) = commit_err {
                            ComposeAction::Notice(format!(" ✗ {}", e))
                        } else {
                            *field = match *field {
                                ComposeField::To     => ComposeField::Body,
                                ComposeField::Body   => ComposeField::Attach,
                                ComposeField::Attach => ComposeField::Body,
                            };
                            ComposeAction::None
                        }
                    }
                    KeyCode::Enter => match field {
                        // Enter in To jumps straight to the body
                        ComposeField::To => {
                            *field = ComposeField::Body;
                            ComposeAction::None
                        }
                        // Enter in Attach adds the typed path to the queue
                        ComposeField::Attach => {
                            let path = attach_input.trim().to_string();
                            if path.is_empty() {
                                ComposeAction::None
                            } else {
                                match validate_attachment(&path) {
                                    Ok(size) => {
                                        attachments.push(path.clone());
                                        attach_input.clear();
                                        ComposeAction::Notice(format!(
                                            " ✓ Attached {} ({})",
                                            path,
                                            human_size(size)
                                        ))
                                    }
                                    Err(e) => ComposeAction::Notice(format!(" ✗ {}", e)),
                                }
                            }
                        }
                        // Enter in the body inserts a newline
                        ComposeField::Body => {
                            body.push('\n');
                            ComposeAction::None
                        }
                    },
                    KeyCode::Backspace => {
                        match field {
                            ComposeField::To => { to.pop(); }
                            ComposeField::Attach => {
                                // Backspace on an empty input removes the last file
                                if attach_input.is_empty() {
                                    attachments.pop();
                                } else {
                                    attach_input.pop();
                                }
                            }
                            ComposeField::Body => { body.pop(); }
                        }
                        ComposeAction::None
                    }
                    // Plain character (ignore ctrl-combos so they don't insert text)
                    KeyCode::Char(c) if !ctrl => {
                        match field {
                            ComposeField::To     => to.push(c),
                            ComposeField::Attach => attach_input.push(c),
                            ComposeField::Body   => body.push(c),
                        }
                        ComposeAction::None
                    }
                    _ => ComposeAction::None,
                };

                // Act on the action now that the &mut borrow above has ended.
                match action {
                    ComposeAction::None => {}
                    ComposeAction::Notice(msg) => state.status = msg,
                    ComposeAction::Abort => {
                        state.mode = Mode::Normal;
                        state.status = " Compose aborted".to_string();
                    }
                    ComposeAction::Send { to, body, attachments } => {
                        let to = to.trim().to_string();
                        let body = body.trim().to_string();
                        if to.is_empty() || body.is_empty() {
                            state.status = " ✗ Recipient and body required".to_string();
                        } else {
                            state.status = " Sending…".to_string();
                            terminal.draw(|f| draw(f, &mut state))?;
                            match resolve_recipient(cfg, store, &to) {
                                Ok(resolved) => {
                                    match transport::send_smtp(cfg, &resolved, &body, &attachments).await {
                                        Ok(_) => {
                                            // Record sent message with its attachments,
                                            // stored separately from the body.
                                            let store_atts = paths_to_attachments(&attachments);
                                            store.record_sent(&resolved, &body, store_atts).ok();
                                            state.reload_messages();
                                            // Always show the file count so it's
                                            // obvious whether attachments were sent.
                                            state.status = if attachments.is_empty() {
                                                format!(" ✓ Sent to {} (no attachments)", resolved)
                                            } else {
                                                format!(" ✓ Sent to {} + {} file(s)", resolved, attachments.len())
                                            };
                                            state.mode = Mode::Normal;
                                        }
                                        // Keep the draft open so it can be retried.
                                        Err(e) => {
                                            state.status = format!(" ✗ Send failed: {}", e)
                                        }
                                    }
                                }
                                Err(e) => state.status = format!(" ✗ {}", e),
                            }
                        }
                    }
                }
            }
            if in_compose {
                // The modal consumes every key — never fall through to global
                // keybinds (otherwise typing 'q' would quit, etc.).
                continue;
            }

            // ── Attachment viewer overlay input ──────────────────────────────
            let in_view = matches!(state.mode, Mode::ViewAttachment { .. });
            if let Mode::ViewAttachment { scroll, .. } = &mut state.mode {
                match key.code {
                    KeyCode::Esc | KeyCode::Char('q') => {
                        state.mode = Mode::Normal;
                    }
                    KeyCode::Down | KeyCode::Char('j') => {
                        *scroll = scroll.saturating_add(1);
                    }
                    KeyCode::Up | KeyCode::Char('k') => {
                        *scroll = scroll.saturating_sub(1);
                    }
                    KeyCode::PageDown => {
                        *scroll = scroll.saturating_add(20);
                    }
                    KeyCode::PageUp => {
                        *scroll = scroll.saturating_sub(20);
                    }
                    _ => {}
                }
            }
            if in_view {
                continue;
            }

            // ── AddContact overlay input ─────────────────────────────────────
            let in_add_contact = matches!(state.mode, Mode::AddContact { .. });
            let contact_action = if let Mode::AddContact { address, nickname, field } = &mut state.mode {
                let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
                match key.code {
                    KeyCode::Esc => ContactAction::Abort,
                    // Tab / Enter on Address → move to Nickname
                    KeyCode::Tab | KeyCode::Enter if *field == AddContactField::Address => {
                        *field = AddContactField::Nickname;
                        ContactAction::None
                    }
                    // Enter / Ctrl+S on Nickname → submit
                    KeyCode::Enter | KeyCode::Char('s') if *field == AddContactField::Nickname || key.code == KeyCode::Char('s') && ctrl => {
                        ContactAction::AddContact {
                            address: address.trim().to_string(),
                            nickname: nickname.trim().to_string(),
                        }
                    }
                    KeyCode::Backspace => {
                        match field {
                            AddContactField::Address  => { address.pop(); }
                            AddContactField::Nickname => { nickname.pop(); }
                        }
                        ContactAction::None
                    }
                    KeyCode::Char(c) if !ctrl => {
                        match field {
                            AddContactField::Address  => address.push(c),
                            AddContactField::Nickname => nickname.push(c),
                        }
                        ContactAction::None
                    }
                    _ => ContactAction::None,
                }
            } else {
                ContactAction::None
            };
            if in_add_contact {
                match contact_action {
                    ContactAction::None => {}
                    ContactAction::Abort => {
                        state.mode = Mode::Normal;
                        state.status = " Cancelled".to_string();
                    }
                    ContactAction::AddContact { address, nickname } => {
                        if address.is_empty() {
                            state.status = " ✗ Address required".to_string();
                        } else {
                            let nick = if nickname.is_empty() { None } else { Some(nickname.as_str()) };
                            match state.store.add_contact(&address, nick) {
                                Ok(c) => {
                                    // Select the newly added contact
                                    let contacts = state.store.all_contacts();
                                    state.contact_selected = contacts
                                        .iter()
                                        .position(|x| x.address == c.address)
                                        .unwrap_or(0);
                                    state.mode = Mode::Normal;
                                    state.status = format!(" ✓ Contact added: {}", address);
                                }
                                Err(e) => state.status = format!(" ✗ {}", e),
                            }
                        }
                    }
                    ContactAction::SetNickname { .. } => {}
                }
                continue;
            }

            // ── SetNickname overlay input ────────────────────────────────────
            let in_set_nickname = matches!(state.mode, Mode::SetNickname { .. });
            let nick_action = if let Mode::SetNickname { address, nickname } = &mut state.mode {
                let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
                match key.code {
                    KeyCode::Esc => ContactAction::Abort,
                    KeyCode::Enter | KeyCode::Char('s') if !matches!(key.code, KeyCode::Char('s')) || ctrl => {
                        ContactAction::SetNickname {
                            address: address.clone(),
                            nickname: nickname.trim().to_string(),
                        }
                    }
                    KeyCode::Backspace => { nickname.pop(); ContactAction::None }
                    KeyCode::Char(c) if !ctrl => { nickname.push(c); ContactAction::None }
                    _ => ContactAction::None,
                }
            } else {
                ContactAction::None
            };
            if in_set_nickname {
                match nick_action {
                    ContactAction::None => {}
                    ContactAction::Abort => {
                        state.mode = Mode::Normal;
                        state.status = " Cancelled".to_string();
                    }
                    ContactAction::SetNickname { address, nickname } => {
                        match state.store.set_nickname(&address, &nickname) {
                            Ok(_) => {
                                state.mode = Mode::Normal;
                                let desc = if nickname.is_empty() {
                                    format!(" ✓ Nickname cleared for {}", address)
                                } else {
                                    format!(" ✓ Nickname '{}' set for {}", nickname, address)
                                };
                                state.status = desc;
                            }
                            Err(e) => state.status = format!(" ✗ {}", e),
                        }
                    }
                    _ => {}
                }
                continue;
            }

            // ── Contacts pane keybinds (when Contacts pane is focused) ───────
            if state.focus == Focus::Contacts && state.show_contacts {
                let contacts = state.store.all_contacts();
                let n = contacts.len();
                let consumed = match key.code {
                    KeyCode::Down | KeyCode::Char('j') => {
                        if n > 0 { state.contact_selected = (state.contact_selected + 1).min(n - 1); }
                        true
                    }
                    KeyCode::Up | KeyCode::Char('k') => {
                        state.contact_selected = state.contact_selected.saturating_sub(1);
                        true
                    }
                    KeyCode::Char('a') => {
                        state.mode = Mode::AddContact {
                            address: String::new(),
                            nickname: String::new(),
                            field: AddContactField::Address,
                        };
                        state.status =
                            " Add contact — type address, Tab for nickname, Enter to save, Esc cancel"
                                .to_string();
                        true
                    }
                    KeyCode::Char('d') => {
                        if let Some(c) = contacts.get(state.contact_selected) {
                            let addr = c.address.clone();
                            match state.store.delete_contact(&addr) {
                                Ok(_) => {
                                    let new_n = state.store.all_contacts().len();
                                    if new_n > 0 {
                                        state.contact_selected =
                                            state.contact_selected.min(new_n - 1);
                                    } else {
                                        state.contact_selected = 0;
                                    }
                                    state.status = format!(" ✓ Deleted contact {}", addr);
                                }
                                Err(e) => state.status = format!(" ✗ {}", e),
                            }
                        }
                        true
                    }
                    KeyCode::Char('n') => {
                        if let Some(c) = contacts.get(state.contact_selected) {
                            let current_nick = c.nickname.clone().unwrap_or_default();
                            state.mode = Mode::SetNickname {
                                address: c.address.clone(),
                                nickname: current_nick,
                            };
                            state.status = format!(
                                " Nickname for {} — type alias, Enter to save (empty = clear), Esc cancel",
                                c.address
                            );
                        }
                        true
                    }
                    _ => false,
                };
                if consumed { continue; }
            }

            let ch = match key.code {
                KeyCode::Char(c) => Some(c.to_string()),
                _ => None,
            };

            // ── Global keybinds ──────────────────────────────────────────────
            if let Some(ref k) = ch {
                if k == &kb.quit {
                    break;
                }

                if k == &kb.sync {
                    state.status = " Syncing…".to_string();
                    terminal.draw(|f| draw(f, &mut state))?;
                    let unread_before = store.unread_count();
                    match transport::fetch_imap(cfg, store).await {
                        Ok(_) => {
                            state.reload_messages();
                            let unread_after = store.unread_count();
                            if unread_after > unread_before {
                                bell();
                            }
                            state.status = format!(
                                " Sync complete  •  {} unread",
                                store.unread_count()
                            );
                        }
                        Err(e) => state.status = format!(" Sync error: {}", e),
                    }
                    last_sync = Instant::now(); // reset auto-sync timer
                    continue;
                }

                if k == &kb.compose {
                    state.mode = Mode::Compose {
                        to: String::new(),
                        body: String::new(),
                        attachments: Vec::new(),
                        attach_input: String::new(),
                        field: ComposeField::To,
                    };
                    state.status = " Compose — type To, Tab to body, Tab again for attach, Ctrl+S send, Esc cancel".to_string();
                    continue;
                }

                if k == &kb.reply {
                    if let Some(msg) = state.reading.clone() {
                        state.mode = Mode::Compose {
                            to: msg.from.clone(),
                            body: String::new(),
                            attachments: Vec::new(),
                            attach_input: String::new(),
                            field: ComposeField::Body,
                        };
                        state.status = " Reply — type body, Ctrl+S send, Tab for attach field, Esc cancel".to_string();
                    }
                    continue;
                }

                if k == &kb.star {
                    if let Some(idx) = state.selected_store_index() {
                        state.store.toggle_star(idx).ok();
                        state.reload_messages();
                    }
                    continue;
                }

                if k == &kb.delete {
                    if let Some(idx) = state.selected_store_index() {
                        // Grab the UID before we move the message locally
                        let uid = state.store.get_message(idx).and_then(|m| m.uid);

                        // Always apply the local trash move immediately
                        state.store.move_to_trash(idx).ok();
                        state.reload_messages();
                        state.status = " Moved to trash".to_string();
                        terminal.draw(|f| draw(f, &mut state))?;

                        // Best-effort: also move on the IMAP server so it
                        // doesn't re-appear on the next sync
                        if let Some(uid) = uid {
                            if let Err(e) = transport::imap_move_to_trash(cfg, uid).await {
                                state.status = format!(
                                    " Local trash OK — IMAP: {}",
                                    e
                                );
                            }
                        }
                    }
                    continue;
                }

                if k == "?" {
                    state.show_contacts = !state.show_contacts;
                    if state.show_contacts {
                        // Opening → jump straight into the contacts pane so
                        // a / d / n work immediately without extra Tab presses.
                        state.focus = Focus::Contacts;
                    } else if state.focus == Focus::Contacts {
                        // Closing while focused on contacts → back to folders.
                        state.focus = Focus::Folders;
                    }
                    continue;
                }
            }

            // ── Ctrl+A: save selected attachment (Reading pane) ──────────────
            if key.code == KeyCode::Char('a')
                && key.modifiers.contains(KeyModifiers::CONTROL)
                && state.focus == Focus::Reading
            {
                if let Some(msg) = &state.reading {
                    if let Some(att) = msg.attachments.get(state.selected_attachment) {
                        match save_attachment_to_disk(att) {
                            Ok(path) => state.status = format!(" ✓ Saved to {}", path),
                            Err(e) => state.status = format!(" ✗ Save failed: {}", e),
                        }
                    }
                }
                continue;
            }

            // ── Navigation ───────────────────────────────────────────────────
            match key.code {
                KeyCode::Tab => {
                    state.focus = match state.focus {
                        Focus::Folders  => if state.show_contacts { Focus::Contacts } else { Focus::Messages },
                        Focus::Contacts => Focus::Messages,
                        Focus::Messages => Focus::Reading,
                        Focus::Reading  => Focus::Folders,
                    };
                }
                KeyCode::BackTab => {
                    state.focus = match state.focus {
                        Focus::Folders  => Focus::Reading,
                        Focus::Contacts => Focus::Folders,
                        Focus::Messages => if state.show_contacts { Focus::Contacts } else { Focus::Folders },
                        Focus::Reading  => Focus::Messages,
                    };
                }
                KeyCode::Left => {
                    if state.focus == Focus::Messages || state.focus == Focus::Reading {
                        state.focus = if state.show_contacts { Focus::Contacts } else { Focus::Folders };
                    } else if state.focus == Focus::Contacts {
                        state.focus = Focus::Folders;
                    }
                }
                KeyCode::Right => {
                    if state.focus == Focus::Folders {
                        state.focus = if state.show_contacts { Focus::Contacts } else { Focus::Messages };
                    } else if state.focus == Focus::Contacts {
                        state.focus = Focus::Messages;
                    }
                }
                KeyCode::Down | KeyCode::Char('j') => {
                    match state.focus {
                        Focus::Folders  => state.next_folder(),
                        Focus::Contacts => {} // handled above in contacts block
                        Focus::Messages => state.next_msg(),
                        Focus::Reading  => {
                            // Navigate through attachments
                            if let Some(msg) = &state.reading {
                                let n = msg.attachments.len();
                                if n > 0 && state.selected_attachment + 1 < n {
                                    state.selected_attachment += 1;
                                }
                            }
                        }
                    }
                }
                KeyCode::Up | KeyCode::Char('k') => {
                    match state.focus {
                        Focus::Folders  => state.prev_folder(),
                        Focus::Contacts => {} // handled above in contacts block
                        Focus::Messages => state.prev_msg(),
                        Focus::Reading  => {
                            if state.selected_attachment > 0 {
                                state.selected_attachment -= 1;
                            }
                        }
                    }
                }
                KeyCode::Enter => {
                    if state.focus == Focus::Reading {
                        // Open the selected attachment inline if it's text.
                        if let Some(msg) = &state.reading {
                            if let Some(att) = msg.attachments.get(state.selected_attachment) {
                                match try_decode_text(att) {
                                    Ok(content) => {
                                        state.mode = Mode::ViewAttachment {
                                            filename: att.filename.clone(),
                                            content,
                                            scroll: 0,
                                        };
                                    }
                                    Err(e) => {
                                        state.status = format!(
                                            " ✗ Cannot preview: {} — use Ctrl+A to save",
                                            e
                                        );
                                    }
                                }
                            }
                        }
                    } else {
                        state.open_selected();
                    }
                }
                _ => {}
            }
        }
    }

    Ok(())
}

// ─── Drawing ─────────────────────────────────────────────────────────────────

fn draw(f: &mut Frame, state: &mut AppState) {
    let area = f.size();

    // Outer: status bar at bottom
    let outer = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Min(1), Constraint::Length(1)])
        .split(area);

    let main_area = outer[0];
    let status_area = outer[1];

    // Main: sidebar | content
    let main_split = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([Constraint::Length(22), Constraint::Min(1)])
        .split(main_area);

    let sidebar_area = main_split[0];
    let content_area = main_split[1];

    // Content: message list (top) | reading pane (bottom)
    let content_split = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Percentage(40), Constraint::Percentage(60)])
        .split(content_area);

    let list_area = content_split[0];
    let read_area = content_split[1];

    draw_sidebar(f, state, sidebar_area);
    draw_message_list(f, state, list_area);
    draw_reading_pane(f, state, read_area);
    draw_status_bar(f, state, status_area);

    // Draw compose overlay if in compose mode
    if let Mode::Compose { to, body, attachments, attach_input, field } = &state.mode {
        draw_compose(f, to, body, attachments, attach_input, *field, area);
    }

    // Draw attachment viewer overlay (rendered on top of everything)
    if let Mode::ViewAttachment { filename, content, scroll } = &state.mode {
        draw_attachment_viewer(f, filename, content, *scroll, area);
    }

    // Draw contact management overlays
    if let Mode::AddContact { address, nickname, field } = &state.mode {
        draw_add_contact(f, address, nickname, *field, area);
    }
    if let Mode::SetNickname { address, nickname } = &state.mode {
        draw_set_nickname(f, address, nickname, area);
    }
}

fn draw_sidebar(f: &mut Frame, state: &mut AppState, area: Rect) {
    let border_color = if state.focus == Focus::Folders {
        Color::Cyan
    } else {
        Color::DarkGray
    };
    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Folders ")
        .border_style(Style::default().fg(border_color));

    let inner = block.inner(area);
    f.render_widget(block, area);

    // Folder list
    let folder_items: Vec<ListItem> = FOLDERS
        .iter()
        .enumerate()
        .map(|(i, folder)| {
            let unread = state.store.unread_in(folder);
            let label = if unread > 0 {
                format!(" {} ({})", folder.label(), unread)
            } else {
                format!(" {}", folder.label())
            };
            let style = if i == state.folder_idx {
                Style::default()
                    .fg(Color::Black)
                    .bg(Color::Cyan)
                    .add_modifier(Modifier::BOLD)
            } else if unread > 0 {
                Style::default().fg(Color::Yellow)
            } else {
                Style::default().fg(Color::White)
            };
            ListItem::new(label).style(style)
        })
        .collect();

    // Split sidebar: folders top, contacts bottom
    let sidebar_split = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Length(FOLDERS.len() as u16 + 2), Constraint::Min(1)])
        .split(inner);

    let folder_list = List::new(folder_items);
    f.render_widget(folder_list, sidebar_split[0]);

    // Contacts panel
    let contacts_focused = state.focus == Focus::Contacts;
    let contacts_border_color = if contacts_focused { Color::Cyan } else { Color::DarkGray };
    let contacts_block = Block::default()
        .borders(Borders::TOP)
        .title(" Contacts [?] ")
        .border_style(Style::default().fg(contacts_border_color));

    if state.show_contacts {
        let inner_contacts = contacts_block.inner(sidebar_split[1]);
        f.render_widget(contacts_block, sidebar_split[1]);

        // Split the inner area: list + 1-line hint at bottom
        let contacts_split = Layout::default()
            .direction(Direction::Vertical)
            .constraints([Constraint::Min(1), Constraint::Length(1)])
            .split(inner_contacts);

        let all = state.store.all_contacts();
        let items: Vec<ListItem> = all
            .iter()
            .enumerate()
            .map(|(i, c)| {
                let selected = contacts_focused && i == state.contact_selected;
                let nick_part = c
                    .nickname
                    .as_deref()
                    .map(|n| format!(" ({})", n))
                    .unwrap_or_default();
                let label = format!(" [{}] {}{}", c.id, c.user, nick_part);
                if selected {
                    ListItem::new(label).style(
                        Style::default()
                            .fg(Color::Black)
                            .bg(Color::Cyan)
                            .add_modifier(Modifier::BOLD),
                    )
                } else {
                    ListItem::new(label).style(Style::default().fg(Color::Gray))
                }
            })
            .collect();
        f.render_widget(List::new(items), contacts_split[0]);

        // Hint row
        let hint = if contacts_focused {
            Span::styled(
                " a add · d del · n nick",
                Style::default().fg(Color::DarkGray),
            )
        } else {
            Span::styled(
                " Tab to manage",
                Style::default().fg(Color::DarkGray),
            )
        };
        f.render_widget(Paragraph::new(Line::from(hint)), contacts_split[1]);
    } else {
        let count = state.store.all_contacts().len();
        let p = Paragraph::new(format!(" {} contacts\n [?] to manage", count))
            .style(Style::default().fg(Color::DarkGray));
        let inner_contacts = contacts_block.inner(sidebar_split[1]);
        f.render_widget(contacts_block, sidebar_split[1]);
        f.render_widget(p, inner_contacts);
    }
}

fn draw_message_list(f: &mut Frame, state: &mut AppState, area: Rect) {
    let folder_name = state.current_folder().label();
    let title = format!(" {} — {} messages ", folder_name, state.messages.len());

    let items: Vec<ListItem> = state
        .messages
        .iter()
        .map(|(_, msg)| {
            let unread_dot = if !msg.read { "●" } else { " " };
            let star = if msg.starred { "★" } else { " " };
            let clip = if msg.attachments.is_empty() { " " } else { "📎" };
            let date = msg.timestamp.format("%b %d %H:%M").to_string();
            let from = truncate(&msg.from, 22);
            let preview: String = msg.body.lines().next().unwrap_or("").chars().take(30).collect();

            let line = Line::from(vec![
                Span::styled(unread_dot, Style::default().fg(Color::Cyan)),
                Span::raw(star),
                Span::raw(clip),
                Span::raw(" "),
                Span::styled(format!("{:<22}", from), Style::default().fg(Color::White)),
                Span::raw(" "),
                Span::styled(format!("{:<14}", date), Style::default().fg(Color::DarkGray)),
                Span::styled(preview, Style::default().fg(Color::Gray)),
            ]);

            let style = if !msg.read {
                Style::default().add_modifier(Modifier::BOLD)
            } else {
                Style::default()
            };
            ListItem::new(line).style(style)
        })
        .collect();

    let border_color = if state.focus == Focus::Messages {
        Color::Cyan
    } else {
        Color::DarkGray
    };
    let list = List::new(items)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title(title)
                .border_style(Style::default().fg(border_color)),
        )
        .highlight_style(
            Style::default()
                .bg(Color::DarkGray)
                .add_modifier(Modifier::BOLD),
        );

    f.render_stateful_widget(list, area, &mut state.msg_list_state);
}

fn draw_reading_pane(f: &mut Frame, state: &mut AppState, area: Rect) {
    let border_color = if state.focus == Focus::Reading {
        Color::Cyan
    } else {
        Color::DarkGray
    };
    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Message ")
        .border_style(Style::default().fg(border_color));

    let lines: Vec<Line> = match &state.reading {
        None => vec![Line::from("No message selected.")],
        Some(msg) => {
            // Header + body text only — attachments are listed separately below.
            let mut lines = vec![
                Line::from(format!("From : {}", msg.from)),
                Line::from(format!("To   : {}", msg.to)),
                Line::from(format!("Date : {}", msg.timestamp.format("%Y-%m-%d %H:%M:%S"))),
                Line::from("─".repeat(60)),
                Line::from(msg.body.clone()),
            ];

            if !msg.attachments.is_empty() {
                lines.push(Line::from(""));
                lines.push(Line::from(Span::styled(
                    format!("📎 Attachments ({})", msg.attachments.len()),
                    Style::default().fg(Color::Cyan).add_modifier(Modifier::BOLD),
                )));
                for (i, att) in msg.attachments.iter().enumerate() {
                    let selected = i == state.selected_attachment && state.focus == Focus::Reading;
                    let style = if selected {
                        Style::default().fg(Color::Black).bg(Color::Yellow)
                    } else {
                        Style::default().fg(Color::White)
                    };
                    let hint = if selected { "   ← Enter preview · Ctrl+A save" } else { "" };
                    lines.push(Line::from(Span::styled(
                        format!("  {} ({}){}", att.filename, human_size(att.size), hint),
                        style,
                    )));
                }
                if state.focus != Focus::Reading {
                    lines.push(Line::from(Span::styled(
                        "  (Tab to this pane · ↑↓ pick · Enter preview text · Ctrl+A save)",
                        Style::default().fg(Color::DarkGray),
                    )));
                }
            }

            lines
        }
    };

    let paragraph = Paragraph::new(lines)
        .block(block)
        .wrap(Wrap { trim: false })
        .style(Style::default().fg(Color::White));

    f.render_widget(paragraph, area);
}

fn draw_status_bar(f: &mut Frame, state: &AppState, area: Rect) {
    let kb = &state.cfg.keybinds;
    let help = format!(
        "  {}quit  {}compose  {}reply  {}star  {}delete  {}sync  Tab/←→ panes  ↑↓/jk nav  ^A save  ? contacts",
        kb.quit, kb.compose, kb.reply, kb.star, kb.delete, kb.sync
    );

    let bar = Paragraph::new(Line::from(vec![
        Span::styled(&state.status, Style::default().fg(Color::Cyan)),
        Span::styled(&help, Style::default().fg(Color::DarkGray)),
    ]))
    .style(Style::default().bg(Color::Black));

    f.render_widget(bar, area);
}

// ─── Helpers ─────────────────────────────────────────────────────────────────

/// Resolve a compose "To" string into a full email address.
///
/// Resolution order:
/// 1. All digits            → contact ID lookup
/// 2. Matches a nickname    → that contact's address (case-insensitive)
/// 3. Contains '@'          → use as-is, register if new
/// 4. Otherwise             → bare username, append config domain
fn resolve_recipient(cfg: &Config, store: &MailStore, to: &str) -> Result<String> {
    let to = to.trim();
    // Numeric ID
    if !to.is_empty() && to.chars().all(|c| c.is_ascii_digit()) {
        return store.resolve_contact_id(to);
    }
    // Nickname (case-insensitive exact match)
    if let Some(addr) = store.find_by_nickname(to) {
        store.ensure_contact(&addr)?;
        return Ok(addr);
    }
    // Full address or bare username
    let addr = cfg.resolve_address(to);
    store.ensure_contact(&addr)?;
    Ok(addr)
}

/// Read each queued file path and turn it into a stored [`Attachment`]
/// (base64-encoded, MIME guessed from extension). Files that can't be read are
/// silently skipped — the send already succeeded, this is just the local record.
fn paths_to_attachments(paths: &[String]) -> Vec<Attachment> {
    paths
        .iter()
        .filter_map(|path| {
            let data = std::fs::read(path).ok()?;
            let filename = std::path::Path::new(path)
                .file_name()
                .map(|s| s.to_string_lossy().into_owned())
                .unwrap_or_else(|| "attachment".to_string());
            Some(Attachment {
                filename,
                size: data.len() as u64,
                mime_type: transport::guess_mime(path).to_string(),
                data: base64::engine::general_purpose::STANDARD.encode(&data),
            })
        })
        .collect()
}

/// Centered rectangle covering `percent_x` × `percent_y` of `area`.
fn centered_rect(percent_x: u16, percent_y: u16, area: Rect) -> Rect {
    let vertical = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Percentage((100 - percent_y) / 2),
            Constraint::Percentage(percent_y),
            Constraint::Percentage((100 - percent_y) / 2),
        ])
        .split(area);
    Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage((100 - percent_x) / 2),
            Constraint::Percentage(percent_x),
            Constraint::Percentage((100 - percent_x) / 2),
        ])
        .split(vertical[1])[1]
}

/// Render the compose / reply modal: To, Attach, and Body fields, with the
/// focused field highlighted and showing a cursor.
fn draw_compose(
    f: &mut Frame,
    to: &str,
    body: &str,
    attachments: &[String],
    attach_input: &str,
    field: ComposeField,
    area: Rect,
) {
    let modal = centered_rect(70, 60, area);

    // Clear the area behind the modal so the UI underneath doesn't bleed through.
    f.render_widget(Clear, modal);

    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Compose  —  Ctrl+S send · Enter/Tab next field · Esc cancel ")
        .border_style(Style::default().fg(Color::Cyan));
    let inner = block.inner(modal);
    f.render_widget(block, modal);

    // Attach section grows with the number of queued files (capped for layout).
    let attach_h = 2 + attachments.len().min(5) as u16;
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(2),        // To
            Constraint::Length(attach_h), // Attach
            Constraint::Min(1),           // Body
        ])
        .split(inner);

    let label_style = |focused: bool| {
        if focused {
            Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)
        } else {
            Style::default().fg(Color::DarkGray)
        }
    };
    let cursor = |focused: bool| if focused { "_" } else { "" };

    // ── To field ──
    let to_focused = field == ComposeField::To;
    let to_line = Line::from(vec![
        Span::styled("To: ", label_style(to_focused)),
        Span::styled(format!("{}{}", to, cursor(to_focused)), Style::default().fg(Color::White)),
    ]);
    f.render_widget(
        Paragraph::new(to_line).block(
            Block::default()
                .borders(Borders::BOTTOM)
                .border_style(Style::default().fg(Color::DarkGray)),
        ),
        chunks[0],
    );

    // ── Attach field ──
    // The hint only shows when the input is empty so it doesn't slide
    // alongside the typed text.
    let attach_focused = field == ComposeField::Attach;
    let attach_first_line = if attach_input.is_empty() {
        Line::from(vec![
            Span::styled("Attach: ", label_style(attach_focused)),
            Span::styled(cursor(attach_focused).to_string(), Style::default().fg(Color::White)),
            Span::styled(
                "  type a path, Enter to queue · any type <25MB",
                Style::default().fg(Color::DarkGray),
            ),
        ])
    } else {
        Line::from(vec![
            Span::styled("Attach: ", label_style(attach_focused)),
            Span::styled(
                format!("{}{}", attach_input, cursor(attach_focused)),
                Style::default().fg(Color::White),
            ),
        ])
    };
    let mut attach_lines = vec![attach_first_line];
    for path in attachments.iter().take(5) {
        attach_lines.push(Line::from(Span::styled(
            format!("  📎 {}", path),
            Style::default().fg(Color::Green),
        )));
    }
    if attachments.len() > 5 {
        attach_lines.push(Line::from(Span::styled(
            format!("  …and {} more", attachments.len() - 5),
            Style::default().fg(Color::DarkGray),
        )));
    }
    f.render_widget(
        Paragraph::new(attach_lines).block(
            Block::default()
                .borders(Borders::BOTTOM)
                .border_style(Style::default().fg(Color::DarkGray)),
        ),
        chunks[1],
    );

    // ── Body field ──
    let body_focused = field == ComposeField::Body;
    f.render_widget(
        Paragraph::new(format!("{}{}", body, cursor(body_focused)))
            .wrap(Wrap { trim: false })
            .style(Style::default().fg(Color::White)),
        chunks[2],
    );
}

/// Validate a candidate attachment: must exist, be a file, and be under the
/// size limit. Any file type is allowed (binary included). Returns the size.
fn validate_attachment(path: &str) -> std::result::Result<u64, String> {
    let p = std::path::Path::new(path);
    let meta = std::fs::metadata(p).map_err(|_| format!("File not found: {}", path))?;
    if !meta.is_file() {
        return Err(format!("Not a file: {}", path));
    }
    let size = meta.len();
    if size > transport::MAX_ATTACHMENT_BYTES {
        return Err(format!("Over 25 MB: {}", path));
    }
    Ok(size)
}

/// Human-readable byte size, e.g. "3.2 KB".
fn human_size(bytes: u64) -> String {
    if bytes >= 1024 * 1024 {
        format!("{:.1} MB", bytes as f64 / (1024.0 * 1024.0))
    } else if bytes >= 1024 {
        format!("{:.1} KB", bytes as f64 / 1024.0)
    } else {
        format!("{} B", bytes)
    }
}

/// Save an attachment to disk in the Downloads folder (falling back to
/// Documents, then a temp dir). Returns the path where it was written.
fn save_attachment_to_disk(att: &Attachment) -> std::result::Result<String, String> {
    use std::path::PathBuf;

    let dir = if let Some(home) = dirs::home_dir() {
        let candidates = [home.join("Downloads"), home.join("Documents"), home.clone()];
        candidates
            .iter()
            .find(|p| p.is_dir())
            .cloned()
            .unwrap_or_else(|| {
                #[cfg(target_os = "windows")]
                { PathBuf::from(env::var("TEMP").unwrap_or_else(|_| ".".to_string())) }
                #[cfg(not(target_os = "windows"))]
                { PathBuf::from("/tmp") }
            })
    } else {
        PathBuf::from(".")
    };

    let path = dir.join(&att.filename);

    let data = base64::engine::general_purpose::STANDARD
        .decode(&att.data)
        .map_err(|e| format!("Decode failed: {}", e))?;

    std::fs::write(&path, data).map_err(|e| format!("Write failed: {}", e))?;

    Ok(path.display().to_string())
}

/// Emit a terminal BEL character. Written to stderr so it doesn't interfere
/// with ratatui's stdout buffer.
fn bell() {
    eprint!("\x07");
}

fn truncate(s: &str, max: usize) -> String {
    if s.chars().count() <= max {
        s.to_string()
    } else {
        format!("{}…", s.chars().take(max - 1).collect::<String>())
    }
}

/// Render a full-screen overlay showing the contents of a text attachment.
fn draw_attachment_viewer(f: &mut Frame, filename: &str, content: &str, scroll: u16, area: Rect) {
    let modal = centered_rect(88, 85, area);
    f.render_widget(Clear, modal);

    let block = Block::default()
        .borders(Borders::ALL)
        .title(format!(" 📄 {}  —  ↑↓/jk scroll · PgUp/PgDn · Esc close ", filename))
        .border_style(Style::default().fg(Color::Yellow));

    let inner = block.inner(modal);
    f.render_widget(block, modal);

    let p = Paragraph::new(content.to_string())
        .scroll((scroll, 0))
        .wrap(Wrap { trim: false })
        .style(Style::default().fg(Color::White));

    f.render_widget(p, inner);
}

/// Render the "Add contact" overlay.
fn draw_add_contact(
    f: &mut Frame,
    address: &str,
    nickname: &str,
    field: AddContactField,
    area: Rect,
) {
    let modal = centered_rect(60, 30, area);
    f.render_widget(Clear, modal);

    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Add contact  —  Tab next field · Enter save · Esc cancel ")
        .border_style(Style::default().fg(Color::Cyan));
    let inner = block.inner(modal);
    f.render_widget(block, modal);

    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Length(2), Constraint::Length(2), Constraint::Min(1)])
        .split(inner);

    let label_style = |focused: bool| {
        if focused {
            Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)
        } else {
            Style::default().fg(Color::DarkGray)
        }
    };
    let cursor = |focused: bool| if focused { "_" } else { "" };

    // Address field
    let addr_focused = field == AddContactField::Address;
    f.render_widget(
        Paragraph::new(Line::from(vec![
            Span::styled("Address:  ", label_style(addr_focused)),
            Span::styled(
                format!("{}{}", address, cursor(addr_focused)),
                Style::default().fg(Color::White),
            ),
        ]))
        .block(
            Block::default()
                .borders(Borders::BOTTOM)
                .border_style(Style::default().fg(Color::DarkGray)),
        ),
        chunks[0],
    );

    // Nickname field
    let nick_focused = field == AddContactField::Nickname;
    let nick_hint = if nickname.is_empty() && !nick_focused {
        Span::styled("  optional", Style::default().fg(Color::DarkGray))
    } else {
        Span::raw("")
    };
    f.render_widget(
        Paragraph::new(Line::from(vec![
            Span::styled("Nickname: ", label_style(nick_focused)),
            Span::styled(
                format!("{}{}", nickname, cursor(nick_focused)),
                Style::default().fg(Color::White),
            ),
            nick_hint,
        ]))
        .block(
            Block::default()
                .borders(Borders::BOTTOM)
                .border_style(Style::default().fg(Color::DarkGray)),
        ),
        chunks[1],
    );

    // Hint
    f.render_widget(
        Paragraph::new(Span::styled(
            " Nickname lets you type it in the To field instead of the address",
            Style::default().fg(Color::DarkGray),
        )),
        chunks[2],
    );
}

/// Render the "Set nickname" overlay for an existing contact.
fn draw_set_nickname(f: &mut Frame, address: &str, nickname: &str, area: Rect) {
    let modal = centered_rect(56, 26, area);
    f.render_widget(Clear, modal);

    let block = Block::default()
        .borders(Borders::ALL)
        .title(" Set nickname  —  Enter save · empty = clear · Esc cancel ")
        .border_style(Style::default().fg(Color::Cyan));
    let inner = block.inner(modal);
    f.render_widget(block, modal);

    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Length(1), Constraint::Length(2), Constraint::Min(1)])
        .split(inner);

    f.render_widget(
        Paragraph::new(Span::styled(
            format!(" {}", address),
            Style::default().fg(Color::White).add_modifier(Modifier::BOLD),
        )),
        chunks[0],
    );

    f.render_widget(
        Paragraph::new(Line::from(vec![
            Span::styled("Nickname: ", Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)),
            Span::styled(format!("{}_", nickname), Style::default().fg(Color::White)),
        ]))
        .block(
            Block::default()
                .borders(Borders::BOTTOM)
                .border_style(Style::default().fg(Color::DarkGray)),
        ),
        chunks[1],
    );

    f.render_widget(
        Paragraph::new(Span::styled(
            " Leave empty and press Enter to clear the nickname",
            Style::default().fg(Color::DarkGray),
        )),
        chunks[2],
    );
}

/// Try to decode an attachment as UTF-8 text for inline preview.
/// Succeeds for any file whose bytes are valid UTF-8 (text, markdown, source
/// code, CSV, …). Returns an error for binary files.
fn try_decode_text(att: &Attachment) -> std::result::Result<String, String> {
    let data = base64::engine::general_purpose::STANDARD
        .decode(&att.data)
        .map_err(|e| format!("Base64 decode error: {}", e))?;
    String::from_utf8(data)
        .map_err(|_| "Binary file — not valid UTF-8 text".to_string())
}