// main_screen.rs — F1 main view rendering
//
// The default four-pane layout: autonomous, conversation, tools, status bar.
// Contains draw_main (the App method), draw_conversation_pane, and draw_pane.

use ratatui::{
    layout::{Constraint, Direction, Layout, Rect},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, Paragraph, Wrap},
    Frame,
    crossterm::event::{KeyCode, KeyEvent, KeyModifiers, MouseEvent, MouseEventKind, MouseButton},
};

use super::{
    App, HotkeyAction, ScreenAction, ScreenView,
    screen_legend,
};
use crate::mind::StreamTarget;
use crate::mind::MindCommand;

// --- Slash command table ---

type CmdHandler = fn(&InteractScreen, &str);

struct SlashCommand {
    name: &'static str,
    help: &'static str,
    handler: CmdHandler,
}

fn commands() -> Vec<SlashCommand> { vec![
    SlashCommand { name: "/quit",  help: "Exit consciousness",
        handler: |_, _| {} },
    SlashCommand { name: "/new",   help: "Start fresh session (saves current)",
        handler: |s, _| { let _ = s.mind_tx.send(MindCommand::NewSession); } },
    SlashCommand { name: "/save",  help: "Save session to disk",
        handler: |s, _| {
            if let Ok(mut ag) = s.agent.try_lock() { ag.notify("saved"); }
        } },
    SlashCommand { name: "/retry", help: "Re-run last turn",
        handler: |s, _| {
            let agent = s.agent.clone();
            let mind_tx = s.mind_tx.clone();
            tokio::spawn(async move {
                let _act = crate::agent::start_activity(&agent, "retrying...").await;
                let mut ag = agent.lock().await;
                let entries = ag.entries_mut();
                let mut last_user_text = None;
                while let Some(entry) = entries.last() {
                    if entry.message().role == crate::agent::api::types::Role::User {
                        last_user_text = Some(entries.pop().unwrap().message().content_text().to_string());
                        break;
                    }
                    entries.pop();
                }
                drop(ag);
                if let Some(text) = last_user_text {
                    let _ = mind_tx.send(MindCommand::Turn(text, StreamTarget::Conversation));
                }
            });
        } },
    SlashCommand { name: "/model", help: "Show/switch model (/model <name>)",
        handler: |s, arg| {
            if arg.is_empty() {
                if let Ok(mut ag) = s.agent.try_lock() {
                    let names = ag.app_config.model_names();
                    let label = if names.is_empty() {
                        format!("model: {}", ag.model())
                    } else {
                        format!("model: {} ({})", ag.model(), names.join(", "))
                    };
                    ag.notify(label);
                }
            } else {
                let agent = s.agent.clone();
                let name = arg.to_string();
                tokio::spawn(async move {
                    let _act = crate::agent::start_activity(&agent, format!("switching to {}...", name)).await;
                    cmd_switch_model(&agent, &name).await;
                });
            }
        } },
    SlashCommand { name: "/score", help: "Score memory importance",
        handler: |s, _| { let _ = s.mind_tx.send(MindCommand::Score); } },
    SlashCommand { name: "/dmn",   help: "Show DMN state",
        handler: |s, _| {
            let st = s.shared_mind.lock().unwrap();
            if let Ok(mut ag) = s.agent.try_lock() {
                ag.notify(format!("DMN: {:?} ({}/{})", st.dmn, st.dmn_turns, st.max_dmn_turns));
            }
        } },
    SlashCommand { name: "/sleep", help: "Put DMN to sleep",
        handler: |s, _| {
            let mut st = s.shared_mind.lock().unwrap();
            st.dmn = crate::mind::dmn::State::Resting { since: std::time::Instant::now() };
            st.dmn_turns = 0;
            if let Ok(mut ag) = s.agent.try_lock() { ag.notify("DMN sleeping"); }
        } },
    SlashCommand { name: "/wake",  help: "Wake DMN to foraging",
        handler: |s, _| {
            let mut st = s.shared_mind.lock().unwrap();
            if matches!(st.dmn, crate::mind::dmn::State::Off) { crate::mind::dmn::set_off(false); }
            st.dmn = crate::mind::dmn::State::Foraging;
            st.dmn_turns = 0;
            if let Ok(mut ag) = s.agent.try_lock() { ag.notify("DMN foraging"); }
        } },
    SlashCommand { name: "/pause", help: "Full stop — no autonomous ticks (Ctrl+P)",
        handler: |s, _| {
            let mut st = s.shared_mind.lock().unwrap();
            st.dmn = crate::mind::dmn::State::Paused;
            st.dmn_turns = 0;
            if let Ok(mut ag) = s.agent.try_lock() { ag.notify("DMN paused"); }
        } },
    SlashCommand { name: "/help",  help: "Show this help",
        handler: |s, _| { notify_help(&s.agent); } },
]}

fn dispatch_command(input: &str) -> Option<SlashCommand> {
    let cmd_name = input.split_whitespace().next()?;
    commands().into_iter().find(|c| c.name == cmd_name)
}

/// Switch model — used by both /model command and tool-initiated switches.
pub async fn cmd_switch_model(
    agent: &std::sync::Arc<tokio::sync::Mutex<crate::agent::Agent>>,
    name: &str,
) {
    let resolved = {
        let ag = agent.lock().await;
        match ag.app_config.resolve_model(name) {
            Ok(r) => r,
            Err(e) => {
                agent.lock().await.notify(format!("model error: {}", e));
                return;
            }
        }
    };
    let new_client = crate::agent::api::ApiClient::new(
        &resolved.api_base, &resolved.api_key, &resolved.model_id,
    );
    let prompt_changed = {
        let ag = agent.lock().await;
        resolved.prompt_file != ag.prompt_file
    };
    let mut ag = agent.lock().await;
    ag.swap_client(new_client);
    if prompt_changed {
        ag.prompt_file = resolved.prompt_file.clone();
        ag.compact();
        ag.notify(format!("switched to {} (recompacted)", resolved.model_id));
    } else {
        ag.notify(format!("switched to {}", resolved.model_id));
    }
}

fn notify_help(agent: &std::sync::Arc<tokio::sync::Mutex<crate::agent::Agent>>) {
    if let Ok(mut ag) = agent.try_lock() {
        let mut help = String::new();
        for cmd in &commands() {
            help.push_str(&format!("{:12} {}\n", cmd.name, cmd.help));
        }
        help.push_str("Keys: Tab ^Up/Down PgUp/Down Mouse Esc ^P ^R ^K");
        ag.notify(help);
    }
}

/// Turn marker for the conversation pane gutter.
#[derive(Clone, Copy, PartialEq, Default)]
enum Marker {
    #[default]
    None,
    User,
    Assistant,
}

enum PaneTarget {
    Conversation,
    ConversationAssistant,
    Tools,
    ToolResult,
}

const MAX_PANE_LINES: usize = 10_000;

/// Which pane receives scroll keys.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum ActivePane {
    Autonomous,
    Conversation,
    Tools,
}

fn strip_ansi(text: &str) -> String {
    let mut out = String::with_capacity(text.len());
    let mut chars = text.chars().peekable();
    while let Some(ch) = chars.next() {
        if ch == '\x1b' {
            if chars.peek() == Some(&'[') {
                chars.next();
                while let Some(&c) = chars.peek() {
                    if c.is_ascii() && (0x20..=0x3F).contains(&(c as u8)) {
                        chars.next();
                    } else {
                        break;
                    }
                }
                if let Some(&c) = chars.peek() {
                    if c.is_ascii() && (0x40..=0x7E).contains(&(c as u8)) {
                        chars.next();
                    }
                }
            } else if let Some(&c) = chars.peek() {
                if c.is_ascii() && (0x40..=0x5F).contains(&(c as u8)) {
                    chars.next();
                }
            }
        } else {
            out.push(ch);
        }
    }
    out
}

fn new_textarea(lines: Vec<String>) -> tui_textarea::TextArea<'static> {
    let mut ta = tui_textarea::TextArea::new(lines);
    ta.set_cursor_line_style(Style::default());
    ta.set_wrap_mode(tui_textarea::WrapMode::Word);
    ta
}

fn parse_markdown(md: &str) -> Vec<Line<'static>> {
    tui_markdown::from_str(md)
        .lines
        .into_iter()
        .map(|line| {
            let spans: Vec<Span<'static>> = line.spans.into_iter()
                .map(|span| Span::styled(span.content.into_owned(), span.style))
                .collect();
            let mut result = Line::from(spans).style(line.style);
            result.alignment = line.alignment;
            result
        })
        .collect()
}

struct PaneState {
    lines: Vec<Line<'static>>,
    markers: Vec<Marker>,
    /// Cached wrapped height for each line, valid when cached_width matches.
    line_heights: Vec<u16>,
    cached_width: u16,
    current_line: String,
    current_color: Color,
    md_buffer: String,
    use_markdown: bool,
    pending_marker: Marker,
    scroll: u16,
    pinned: bool,
    last_total_lines: u16,
    last_height: u16,
}

impl PaneState {
    fn new(use_markdown: bool) -> Self {
        Self {
            lines: Vec::new(), markers: Vec::new(),
            line_heights: Vec::new(), cached_width: 0,
            current_line: String::new(), current_color: Color::Reset,
            md_buffer: String::new(), use_markdown,
            pending_marker: Marker::None, scroll: 0, pinned: false,
            last_total_lines: 0, last_height: 20,
        }
    }

    fn evict(&mut self) {
        if self.lines.len() > MAX_PANE_LINES {
            let excess = self.lines.len() - MAX_PANE_LINES;
            self.lines.drain(..excess);
            self.markers.drain(..excess);
            let drain = excess.min(self.line_heights.len());
            self.line_heights.drain(..drain);
            self.scroll = self.scroll.saturating_sub(excess as u16);
        }
    }

    fn flush_pending(&mut self) {
        if self.use_markdown && !self.md_buffer.is_empty() {
            let parsed = parse_markdown(&self.md_buffer);
            for (i, line) in parsed.into_iter().enumerate() {
                let marker = if i == 0 { std::mem::take(&mut self.pending_marker) } else { Marker::None };
                self.lines.push(line);
                self.markers.push(marker);
            }
            self.md_buffer.clear();
        }
        if !self.current_line.is_empty() {
            let line = std::mem::take(&mut self.current_line);
            self.lines.push(Line::styled(line, Style::default().fg(self.current_color)));
            self.markers.push(std::mem::take(&mut self.pending_marker));
        }
    }

    fn push_line(&mut self, line: String, color: Color) {
        self.push_line_with_marker(line, color, Marker::None);
    }

    fn push_line_with_marker(&mut self, line: String, color: Color, marker: Marker) {
        self.flush_pending();
        self.lines.push(Line::styled(strip_ansi(&line), Style::default().fg(color)));
        self.markers.push(marker);
        self.evict();
    }

    fn pop_line(&mut self) {
        self.lines.pop();
        self.markers.pop();
        self.line_heights.truncate(self.lines.len());
    }

    fn scroll_up(&mut self, n: u16) {
        self.scroll = self.scroll.saturating_sub(n);
        self.pinned = true;
    }

    fn scroll_down(&mut self, n: u16) {
        let max = self.last_total_lines.saturating_sub(self.last_height);
        self.scroll = (self.scroll + n).min(max);
        if self.scroll >= max { self.pinned = false; }
    }

    /// Ensure cached line heights cover all committed lines at the given width.
    fn compute_heights(&mut self, width: u16) {
        if width != self.cached_width {
            self.line_heights.clear();
            self.cached_width = width;
        }
        self.line_heights.truncate(self.lines.len());
        while self.line_heights.len() < self.lines.len() {
            let i = self.line_heights.len();
            let h = Paragraph::new(self.lines[i].clone())
                .wrap(Wrap { trim: false })
                .line_count(width) as u16;
            self.line_heights.push(h.max(1));
        }
    }

    fn all_lines(&self) -> Vec<Line<'static>> {
        let (lines, _) = self.all_lines_with_markers();
        lines
    }

    fn all_lines_with_markers(&self) -> (Vec<Line<'static>>, Vec<Marker>) {
        let mut lines: Vec<Line<'static>> = self.lines.clone();
        let mut markers: Vec<Marker> = self.markers.clone();
        if self.use_markdown && !self.md_buffer.is_empty() {
            let parsed = parse_markdown(&self.md_buffer);
            let count = parsed.len();
            lines.extend(parsed);
            if count > 0 {
                markers.push(self.pending_marker);
                markers.extend(std::iter::repeat(Marker::None).take(count - 1));
            }
        } else if !self.current_line.is_empty() {
            lines.push(Line::styled(self.current_line.clone(), Style::default().fg(self.current_color)));
            markers.push(self.pending_marker);
        }
        (lines, markers)
    }
}

pub(crate) struct InteractScreen {
    autonomous: PaneState,
    conversation: PaneState,
    tools: PaneState,
    textarea: tui_textarea::TextArea<'static>,
    input_history: Vec<String>,
    history_index: Option<usize>,
    active_pane: ActivePane,
    pane_areas: [Rect; 3],
    turn_started: Option<std::time::Instant>,
    call_started: Option<std::time::Instant>,
    call_timeout_secs: u64,
    // State sync with agent — double buffer
    last_generation: u64,
    last_entries: Vec<crate::agent::context::ConversationEntry>,
    pending_display_count: usize,
    /// Reference to agent for state sync
    agent: std::sync::Arc<tokio::sync::Mutex<crate::agent::Agent>>,
    shared_mind: std::sync::Arc<crate::mind::SharedMindState>,
    mind_tx: tokio::sync::mpsc::UnboundedSender<crate::mind::MindCommand>,
}

impl InteractScreen {
    pub fn new(
        agent: std::sync::Arc<tokio::sync::Mutex<crate::agent::Agent>>,
        shared_mind: std::sync::Arc<crate::mind::SharedMindState>,
        mind_tx: tokio::sync::mpsc::UnboundedSender<crate::mind::MindCommand>,
    ) -> Self {
        Self {
            autonomous: PaneState::new(true),
            conversation: PaneState::new(true),
            tools: PaneState::new(false),
            textarea: new_textarea(vec![String::new()]),
            input_history: Vec::new(),
            history_index: None,
            active_pane: ActivePane::Conversation,
            pane_areas: [Rect::default(); 3],
            turn_started: None,
            call_started: None,
            call_timeout_secs: 60,
            last_generation: 0,
            last_entries: Vec::new(),
            pending_display_count: 0,
            agent,
            shared_mind,
            mind_tx,
        }
    }

    /// Route an agent entry to pane items.
    /// Returns empty vec for entries that shouldn't be displayed.
    fn route_entry(entry: &crate::agent::context::ConversationEntry) -> Vec<(PaneTarget, String, Marker)> {
        use crate::agent::api::types::Role;
        use crate::agent::context::ConversationEntry;

        if let ConversationEntry::Memory { .. } = entry {
            return vec![];
        }

        let msg = entry.message();
        let text = msg.content_text().to_string();

        if text.starts_with("<system-reminder>") {
            return vec![];
        }

        match msg.role {
            Role::User => {
                if text.is_empty() { return vec![]; }
                vec![(PaneTarget::Conversation, text, Marker::User)]
            }
            Role::Assistant => {
                let mut items = Vec::new();
                // Tool calls → tools pane
                if let Some(ref calls) = msg.tool_calls {
                    for call in calls {
                        let line = format!("[{}] {}",
                            call.function.name,
                            call.function.arguments.chars().take(80).collect::<String>());
                        items.push((PaneTarget::Tools, line, Marker::None));
                    }
                }
                // Text content → conversation
                if !text.is_empty() {
                    items.push((PaneTarget::ConversationAssistant, text, Marker::Assistant));
                }
                items
            }
            Role::Tool => {
                if text.is_empty() { return vec![]; }
                vec![(PaneTarget::ToolResult, text, Marker::None)]
            }
            Role::System => vec![],
        }
    }

    /// Sync conversation display from agent entries + pending input.
    fn sync_from_agent(&mut self) {
        // Pop previously-displayed pending input
        for _ in 0..self.pending_display_count {
            self.conversation.pop_line();
        }
        self.pending_display_count = 0;

        // Sync agent entries
        if let Ok(agent) = self.agent.try_lock() {
            let generation = agent.generation;
            let entries = agent.entries();

            // Phase 1: detect desync and pop
            if generation != self.last_generation {
                self.conversation = PaneState::new(true);
                self.autonomous = PaneState::new(true);
                self.tools = PaneState::new(false);
                self.last_entries.clear();
            } else {
                // Pop entries from the tail that don't match
                while !self.last_entries.is_empty() {
                    let i = self.last_entries.len() - 1;
                    if entries.get(i) == Some(&self.last_entries[i]) {
                        break;
                    }
                    let popped = self.last_entries.pop().unwrap();
                    for (target, _, _) in Self::route_entry(&popped) {
                        match target {
                            PaneTarget::Conversation | PaneTarget::ConversationAssistant
                                => self.conversation.pop_line(),
                            PaneTarget::Tools | PaneTarget::ToolResult
                                => self.tools.pop_line(),
                        }
                    }
                }
            }

            // Phase 2: push new entries
            let start = self.last_entries.len();
            for entry in entries.iter().skip(start) {
                for (target, text, marker) in Self::route_entry(entry) {
                    match target {
                        PaneTarget::Conversation =>
                            self.conversation.push_line_with_marker(text, Color::Cyan, marker),
                        PaneTarget::ConversationAssistant =>
                            self.conversation.push_line_with_marker(text, Color::Reset, marker),
                        PaneTarget::Tools =>
                            self.tools.push_line(text, Color::Yellow),
                        PaneTarget::ToolResult => {
                            for line in text.lines().take(20) {
                                self.tools.push_line(format!("  {}", line), Color::DarkGray);
                            }
                        }
                    }
                }
                self.last_entries.push(entry.clone());
            }

            self.last_generation = generation;
        }

        // Display pending input (queued in Mind, not yet accepted)
        let mind = self.shared_mind.lock().unwrap();
        for input in &mind.input {
            self.conversation.push_line_with_marker(
                input.clone(), Color::DarkGray, Marker::User,
            );
            self.pending_display_count += 1;
        }
    }

    /// Dispatch user input — slash commands or conversation.
    fn dispatch_input(&self, input: &str, app: &mut App) {
        let input = input.trim();
        if input.is_empty() { return; }

        if input == "/quit" || input == "/exit" {
            app.should_quit = true;
            return;
        }

        if input.starts_with('/') {
            if let Some(cmd) = dispatch_command(input) {
                (cmd.handler)(self, &input[cmd.name.len()..].trim_start());
            } else {
                if let Ok(mut ag) = self.agent.try_lock() {
                    ag.notify(format!("unknown: {}", input.split_whitespace().next().unwrap_or(input)));
                }
            }
            return;
        }

        // Regular input → queue to Mind
        self.shared_mind.lock().unwrap().input.push(input.to_string());
    }


    fn scroll_active_up(&mut self, n: u16) {
        match self.active_pane {
            ActivePane::Autonomous => self.autonomous.scroll_up(n),
            ActivePane::Conversation => self.conversation.scroll_up(n),
            ActivePane::Tools => self.tools.scroll_up(n),
        }
    }

    fn scroll_active_down(&mut self, n: u16) {
        match self.active_pane {
            ActivePane::Autonomous => self.autonomous.scroll_down(n),
            ActivePane::Conversation => self.conversation.scroll_down(n),
            ActivePane::Tools => self.tools.scroll_down(n),
        }
    }

    fn handle_mouse(&mut self, mouse: MouseEvent) {
        match mouse.kind {
            MouseEventKind::ScrollUp => self.scroll_active_up(3),
            MouseEventKind::ScrollDown => self.scroll_active_down(3),
            MouseEventKind::Down(MouseButton::Left) => {
                let (x, y) = (mouse.column, mouse.row);
                for (i, area) in self.pane_areas.iter().enumerate() {
                    if x >= area.x && x < area.x + area.width && y >= area.y && y < area.y + area.height {
                        self.active_pane = match i { 0 => ActivePane::Autonomous, 1 => ActivePane::Conversation, _ => ActivePane::Tools };
                        break;
                    }
                }
            }
            _ => {}
        }
    }

    /// Draw the main (F1) screen — four-pane layout with status bar.
    fn draw_main(&mut self, frame: &mut Frame, size: Rect, app: &App) {
        // Main layout: content area + active tools overlay + status bar
        let active_tools = app.active_tools.lock().unwrap();
        let tool_lines = active_tools.len() as u16;
        let main_chunks = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Min(3),              // content area
                Constraint::Length(tool_lines),   // active tools (0 when empty)
                Constraint::Length(1),            // status bar
            ])
            .split(size);

        let content_area = main_chunks[0];
        let tools_overlay_area = main_chunks[1];
        let status_area = main_chunks[2];

        // Content: left column (55%) + right column (45%)
        let columns = Layout::default()
            .direction(Direction::Horizontal)
            .constraints([
                Constraint::Percentage(55),
                Constraint::Percentage(45),
            ])
            .split(content_area);

        let left_col = columns[0];
        let right_col = columns[1];

        // Left column: autonomous (35%) + conversation (65%)
        let left_panes = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Percentage(35),
                Constraint::Percentage(65),
            ])
            .split(left_col);

        let auto_area = left_panes[0];
        let conv_area = left_panes[1];

        // Store pane areas for mouse click detection
        self.pane_areas = [auto_area, conv_area, right_col];

        // Draw autonomous pane
        let auto_active = self.active_pane == ActivePane::Autonomous;
        draw_pane(frame, auto_area, "autonomous", &mut self.autonomous, auto_active,
            Some(&screen_legend()));

        // Draw tools pane
        let tools_active = self.active_pane == ActivePane::Tools;
        draw_pane(frame, right_col, "tools", &mut self.tools, tools_active, None);

        // Draw conversation pane (with input line)
        let conv_active = self.active_pane == ActivePane::Conversation;

        // Input area: compute visual height, split, render gutter + textarea
        let input_text = self.textarea.lines().join("\n");
        let input_para_measure = Paragraph::new(input_text).wrap(Wrap { trim: false });
        let input_line_count = (input_para_measure.line_count(conv_area.width.saturating_sub(5)) as u16)
            .max(1)
            .min(5);

        let conv_chunks = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Min(1),                 // conversation text
                Constraint::Length(input_line_count), // input area
            ])
            .split(conv_area);

        let text_area_rect = conv_chunks[0];
        let input_area = conv_chunks[1];

        draw_conversation_pane(frame, text_area_rect, &mut self.conversation, conv_active);

        // " > " gutter + textarea, aligned with conversation messages
        let input_chunks = Layout::default()
            .direction(Direction::Horizontal)
            .constraints([
                Constraint::Length(3),  // " > " gutter
                Constraint::Min(1),    // textarea
            ])
            .split(input_area);

        let gutter = Paragraph::new(Line::styled(
            " > ",
            Style::default().fg(Color::Cyan).add_modifier(Modifier::BOLD),
        ));
        frame.render_widget(gutter, input_chunks[0]);
        frame.render_widget(&self.textarea, input_chunks[1]);

        // Draw active tools overlay
        if !active_tools.is_empty() {
            let tool_style = Style::default().fg(Color::Yellow).add_modifier(Modifier::DIM);
            let tool_text: Vec<Line> = active_tools.iter().map(|t| {
                let elapsed = t.started.elapsed().as_secs();
                let line = if t.detail.is_empty() {
                    format!("  [{}] ({}s)", t.name, elapsed)
                } else {
                    format!("  [{}] {} ({}s)", t.name, t.detail, elapsed)
                };
                Line::styled(line, tool_style)
            }).collect();
            let tool_para = Paragraph::new(tool_text);
            frame.render_widget(tool_para, tools_overlay_area);
        }

        // Draw status bar with live activity indicator
        let timer = if !app.activity.is_empty() {
            let total = self.turn_started.map(|t| t.elapsed().as_secs()).unwrap_or(0);
            let call = self.call_started.map(|t| t.elapsed().as_secs()).unwrap_or(0);
            format!(" {}s, {}/{}s", total, call, self.call_timeout_secs)
        } else {
            String::new()
        };
        let tools_info = if app.status.turn_tools > 0 {
            format!(" ({}t)", app.status.turn_tools)
        } else {
            String::new()
        };
        let activity_part = if app.activity.is_empty() {
            String::new()
        } else {
            format!(" | {}{}{}", app.activity, tools_info, timer)
        };

        let budget_part = if app.status.context_budget.is_empty() {
            String::new()
        } else {
            format!(" [{}]", app.status.context_budget)
        };

        let left_status = format!(
            " {} | {}/{} dmn | {}K tok in{}{}",
            app.status.dmn_state,
            app.status.dmn_turns,
            app.status.dmn_max_turns,
            app.status.prompt_tokens / 1000,
            budget_part,
            activity_part,
        );

        let proc_indicator = if app.running_processes > 0 {
            format!(" {}proc", app.running_processes)
        } else {
            String::new()
        };
        let reason_indicator = if app.reasoning_effort != "none" {
            format!(" reason:{}", app.reasoning_effort)
        } else {
            String::new()
        };
        let right_legend = format!(
            "{}{} ^P:pause ^R:reason ^K:kill | {} ",
            reason_indicator,
            proc_indicator,
            app.status.model,
        );

        // Pad the middle to fill the status bar
        let total_width = status_area.width as usize;
        let used = left_status.len() + right_legend.len();
        let padding = if total_width > used {
            " ".repeat(total_width - used)
        } else {
            " ".to_string()
        };

        let status = Paragraph::new(Line::from(vec![
            Span::styled(&left_status, Style::default().fg(Color::White).bg(Color::DarkGray)),
            Span::styled(padding, Style::default().bg(Color::DarkGray)),
            Span::styled(
                right_legend,
                Style::default().fg(Color::DarkGray).bg(Color::Gray),
            ),
        ]));

        frame.render_widget(status, status_area);
    }
}

impl ScreenView for InteractScreen {
    fn label(&self) -> &'static str { "interact" }

    fn tick(&mut self, frame: &mut Frame, area: Rect,
            events: &[ratatui::crossterm::event::Event], app: &mut App) {
        use ratatui::crossterm::event::Event;
        // Handle events
        for event in events {
            match event {
                Event::Key(key) if key.kind == ratatui::crossterm::event::KeyEventKind::Press => {
            match key.code {
                KeyCode::Esc => { let _ = self.mind_tx.send(crate::mind::MindCommand::Interrupt); }
                KeyCode::Enter if !key.modifiers.contains(KeyModifiers::ALT) && !key.modifiers.contains(KeyModifiers::SHIFT) => {
                    let input: String = self.textarea.lines().join("\n");
                    if !input.is_empty() {
                        if self.input_history.last().map_or(true, |h| h != &input) {
                            self.input_history.push(input.clone());
                        }
                        self.history_index = None;
                        self.dispatch_input(&input, app);
                        self.textarea = new_textarea(vec![String::new()]);
                    }
                }
                KeyCode::Up if key.modifiers.contains(KeyModifiers::CONTROL) => self.scroll_active_up(3),
                KeyCode::Down if key.modifiers.contains(KeyModifiers::CONTROL) => self.scroll_active_down(3),
                KeyCode::Up => {
                    if !self.input_history.is_empty() {
                        let idx = match self.history_index { None => self.input_history.len() - 1, Some(i) => i.saturating_sub(1) };
                        self.history_index = Some(idx);
                        let mut ta = new_textarea(self.input_history[idx].lines().map(String::from).collect());
                        ta.move_cursor(tui_textarea::CursorMove::End);
                        self.textarea = ta;
                    }
                }
                KeyCode::Down => {
                    if let Some(idx) = self.history_index {
                        if idx + 1 < self.input_history.len() {
                            self.history_index = Some(idx + 1);
                            let mut ta = new_textarea(self.input_history[idx + 1].lines().map(String::from).collect());
                            ta.move_cursor(tui_textarea::CursorMove::End);
                            self.textarea = ta;
                        } else {
                            self.history_index = None;
                            self.textarea = new_textarea(vec![String::new()]);
                        }
                    }
                }
                KeyCode::PageUp => self.scroll_active_up(10),
                KeyCode::PageDown => self.scroll_active_down(10),
                KeyCode::Tab => {
                    self.active_pane = match self.active_pane {
                        ActivePane::Autonomous => ActivePane::Tools,
                        ActivePane::Tools => ActivePane::Conversation,
                        ActivePane::Conversation => ActivePane::Autonomous,
                    };
                }
                _ => { self.textarea.input(*key); }
            }
                }
                Event::Mouse(mouse) => { self.handle_mouse(*mouse); }
                _ => {}
            }
        }

        // Sync state from agent
        self.sync_from_agent();

        // Read status from agent + mind state
        if let Ok(mut agent) = self.agent.try_lock() {
            agent.expire_activities();
            app.status.prompt_tokens = agent.last_prompt_tokens();
            app.status.model = agent.model().to_string();
            app.status.context_budget = agent.context.budget.status_string();
            app.activity = agent.activities.last()
                .map(|a| a.label.clone())
                .unwrap_or_default();
        }
        {
            let mind = self.shared_mind.lock().unwrap();
            app.status.dmn_state = mind.dmn.label().to_string();
            app.status.dmn_turns = mind.dmn_turns;
            app.status.dmn_max_turns = mind.max_dmn_turns;
        }

        // Draw
        self.draw_main(frame, area, app);
    }

}

/// Draw the conversation pane with a two-column layout: marker gutter + text.
/// The gutter shows a marker at turn boundaries, aligned with the input gutter.
/// Given per-line heights, a scroll offset, and viewport height,
/// return (first_line, sub_scroll_within_first, last_line_exclusive).
fn visible_range(heights: &[u16], scroll: u16, viewport: u16) -> (usize, u16, usize) {
    let mut row = 0u16;
    let mut first = 0;
    let mut row_at_first = 0u16;
    for (i, &h) in heights.iter().enumerate() {
        if row + h > scroll {
            first = i;
            row_at_first = row;
            break;
        }
        row += h;
        if i == heights.len() - 1 {
            first = heights.len();
            row_at_first = row;
        }
    }
    let sub_scroll = scroll.saturating_sub(row_at_first);

    let mut last = first;
    let mut visible = 0u16;
    for i in first..heights.len() {
        visible += heights[i];
        last = i + 1;
        if visible >= viewport + sub_scroll { break; }
    }
    (first, sub_scroll, last)
}

fn draw_conversation_pane(
    frame: &mut Frame,
    area: Rect,
    pane: &mut PaneState,
    is_active: bool,
) {
    let border_style = if is_active {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    let block = Block::default()
        .title(" conversation ")
        .borders(Borders::ALL)
        .border_style(border_style);

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

    if inner.width < 5 || inner.height == 0 {
        return;
    }

    // Split inner area into gutter (2 chars) + text
    let cols = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Length(2),
            Constraint::Min(1),
        ])
        .split(inner);

    let gutter_area = cols[0];
    let text_area = cols[1];

    let text_width = text_area.width;

    // Cache committed line heights; compute pending tail on the fly
    pane.compute_heights(text_width);
    let (lines, markers) = pane.all_lines_with_markers();

    // Build heights: cached for committed lines, computed for pending tail
    let n_committed = pane.line_heights.len();
    let mut heights: Vec<u16> = pane.line_heights.clone();
    for line in lines.iter().skip(n_committed) {
        let h = Paragraph::new(line.clone())
            .wrap(Wrap { trim: false })
            .line_count(text_width) as u16;
        heights.push(h.max(1));
    }

    let total_visual: u16 = heights.iter().sum();
    pane.last_total_lines = total_visual;
    pane.last_height = inner.height;

    if !pane.pinned {
        pane.scroll = total_visual.saturating_sub(inner.height);
    }

    // Find visible line range
    let (first, sub_scroll, last) = visible_range(&heights, pane.scroll, inner.height);

    // Render only the visible slice — no full-content grapheme walk
    let text_para = Paragraph::new(lines[first..last].to_vec())
        .wrap(Wrap { trim: false })
        .scroll((sub_scroll, 0));
    frame.render_widget(text_para, text_area);

    // Build gutter for the visible slice
    let mut gutter_lines: Vec<Line<'static>> = Vec::new();
    for i in first..last {
        let marker_text = match markers[i] {
            Marker::User => Line::styled("● ", Style::default().fg(Color::Cyan)),
            Marker::Assistant => Line::styled("● ", Style::default().fg(Color::Magenta)),
            Marker::None => Line::raw(""),
        };
        gutter_lines.push(marker_text);
        for _ in 1..heights[i] {
            gutter_lines.push(Line::raw(""));
        }
    }

    let gutter_para = Paragraph::new(gutter_lines)
        .scroll((sub_scroll, 0));
    frame.render_widget(gutter_para, gutter_area);
}

/// Draw a scrollable text pane (free function to avoid borrow issues).
fn draw_pane(
    frame: &mut Frame,
    area: Rect,
    title: &str,
    pane: &mut PaneState,
    is_active: bool,
    left_title: Option<&str>,
) {
    let inner_height = area.height.saturating_sub(2);

    let border_style = if is_active {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    let mut block = Block::default()
        .borders(Borders::ALL)
        .border_style(border_style);
    if let Some(left) = left_title {
        block = block
            .title_top(Line::from(left).left_aligned())
            .title_top(Line::from(format!(" {} ", title)).right_aligned());
    } else {
        block = block.title(format!(" {} ", title));
    }

    let text_width = area.width.saturating_sub(2);
    pane.compute_heights(text_width);
    let lines = pane.all_lines();

    // Build heights: cached for committed, computed for pending tail
    let n_committed = pane.line_heights.len();
    let mut heights: Vec<u16> = pane.line_heights.clone();
    for line in lines.iter().skip(n_committed) {
        let h = Paragraph::new(line.clone())
            .wrap(Wrap { trim: false })
            .line_count(text_width) as u16;
        heights.push(h.max(1));
    }

    let total: u16 = heights.iter().sum();
    pane.last_total_lines = total;
    pane.last_height = inner_height;

    if !pane.pinned {
        pane.scroll = total.saturating_sub(inner_height);
    }

    let (first, sub_scroll, last) = visible_range(&heights, pane.scroll, inner_height);

    let paragraph = Paragraph::new(lines[first..last].to_vec())
        .block(block.clone())
        .wrap(Wrap { trim: false })
        .scroll((sub_scroll, 0));
    frame.render_widget(paragraph, area);
}