use ratatui::{
    layout::{Constraint, Direction, Layout},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, List, ListItem, ListState, Paragraph},
    Frame,
};

use crate::tui::app::App;

pub fn draw(frame: &mut Frame, app: &App) {
    let area = frame.size();

    // Split into sidebar | main column
    let columns = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([Constraint::Length(22), Constraint::Min(0)])
        .split(area);

    draw_sidebar(frame, app, columns[0]);
    draw_main(frame, app, columns[1]);
}

fn draw_sidebar(frame: &mut Frame, app: &App, area: ratatui::layout::Rect) {
    let rows = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Min(0), Constraint::Length(6)])
        .split(area);

    // ── Channel list ────────────────────────────────────────────────────
    let items: Vec<ListItem> = app
        .channels
        .iter()
        .enumerate()
        .map(|(i, (_, name))| {
            let style = if i == app.selected_channel {
                Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)
            } else {
                Style::default()
            };
            ListItem::new(format!("# {}", name)).style(style)
        })
        .collect();

    let mut state = ListState::default();
    state.select(Some(app.selected_channel));

    let channels = List::new(items)
        .block(
            Block::default()
                .title(" Channels ")
                .borders(Borders::ALL)
                .style(Style::default().fg(Color::Cyan)),
        )
        .highlight_style(Style::default().add_modifier(Modifier::BOLD));

    frame.render_stateful_widget(channels, rows[0], &mut state);

    // ── Online users ─────────────────────────────────────────────────────
    let user_items: Vec<ListItem> = app
        .online_users
        .iter()
        .map(|(_, name)| ListItem::new(format!("● {}", name)))
        .collect();

    let online = List::new(user_items).block(
        Block::default()
            .title(" Online ")
            .borders(Borders::ALL)
            .style(Style::default().fg(Color::Green)),
    );
    frame.render_widget(online, rows[1]);
}

fn draw_main(frame: &mut Frame, app: &App, area: ratatui::layout::Rect) {
    let rows = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(1), // channel title bar
            Constraint::Min(0),    // messages
            Constraint::Length(3), // input box
            Constraint::Length(1), // status bar
        ])
        .split(area);

    // ── Title bar ────────────────────────────────────────────────────────
    let title = app
        .current_channel()
        .map(|(_, name)| format!(" # {} ", name))
        .unwrap_or_else(|| " No channel selected ".into());

    let title_bar = Paragraph::new(title)
        .style(Style::default().fg(Color::White).bg(Color::DarkGray).add_modifier(Modifier::BOLD));
    frame.render_widget(title_bar, rows[0]);

    // ── Messages ─────────────────────────────────────────────────────────
    let msgs: Vec<ListItem> = app
        .current_channel_messages()
        .map(|deque| {
            deque
                .iter()
                .map(|m| {
                    ListItem::new(Line::from(vec![
                        Span::styled(
                            format!("{} ", m.timestamp),
                            Style::default().fg(Color::DarkGray),
                        ),
                        Span::styled(
                            format!("{}: ", m.author),
                            Style::default().fg(Color::Cyan).add_modifier(Modifier::BOLD),
                        ),
                        Span::raw(m.content.clone()),
                    ]))
                })
                .collect()
        })
        .unwrap_or_default();

    let message_count = msgs.len();
    let mut list_state = ListState::default();
    if message_count > 0 {
        list_state.select(Some(message_count - 1));
    }

    let messages = List::new(msgs)
        .block(Block::default().borders(Borders::LEFT))
        .highlight_style(Style::default());
    frame.render_stateful_widget(messages, rows[1], &mut list_state);

    // ── Input box ─────────────────────────────────────────────────────────
    let input = Paragraph::new(app.input.as_str())
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title(" Message (Enter to send) "),
        );
    frame.render_widget(input, rows[2]);

    // ── Status bar ────────────────────────────────────────────────────────
    let status_text = app
        .status_msg
        .as_deref()
        .unwrap_or("Ctrl-Q: quit  |  ↑↓: channels  |  Esc: dismiss");
    let status = Paragraph::new(status_text)
        .style(Style::default().fg(Color::DarkGray));
    frame.render_widget(status, rows[3]);
}