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

use crate::feed_state::{FeedHealth, FeedMode, FeedState, HandshakePhase};
use crate::telemetry_frame::TelemetryFrame;
use std::sync::{Arc, Mutex};

#[derive(Clone)]
pub struct FeedDisplayInfo {
    pub label: &'static str,
    pub port: u16,
    pub mode: FeedMode,
}

fn health_indicator(health: FeedHealth) -> Span<'static> {
    match health {
        FeedHealth::Alive => Span::styled(
            "*".to_string(),
            Style::default().fg(Color::Green).add_modifier(Modifier::BOLD),
        ),
        FeedHealth::Stale => Span::styled(
            "~".to_string(),
            Style::default().fg(Color::Yellow),
        ),
        FeedHealth::Waiting => Span::styled(
            ".".to_string(),
            Style::default().fg(Color::DarkGray),
        ),
        FeedHealth::Error => Span::styled(
            "!".to_string(),
            Style::default().fg(Color::Red).add_modifier(Modifier::BOLD),
        ),
    }
}

fn freq_style(health: FeedHealth) -> Style {
    match health {
        FeedHealth::Alive => Style::default().fg(Color::Green),
        FeedHealth::Stale => Style::default().fg(Color::Yellow),
        _ => Style::default().fg(Color::DarkGray),
    }
}

fn format_ago(ago: Option<f64>) -> String {
    match ago {
        None => "never".to_string(),
        Some(t) => format!("{:.2}s", t),
    }
}

fn feed_block_title(info: &FeedDisplayInfo, state: &FeedState) -> String {
    match info.mode {
        FeedMode::Handshake {
            target_port,
            recv_port,
        } => {
            let phase_str = match state.handshake_phase {
                HandshakePhase::NotStarted => "not started",
                HandshakePhase::WaitingForResponse => "waiting",
                HandshakePhase::Subscribing => "subscribing",
                HandshakePhase::Subscribed => "subscribed",
            };
            format!(
                " {} -> :{} recv :{} [{}] ",
                info.label, target_port, recv_port, phase_str
            )
        }
        FeedMode::BindListen => {
            format!(" {}  Port :{} ", info.label, info.port)
        }
        FeedMode::Disabled => {
            format!(" {}  Port :{} [optional, not available] ", info.label, info.port)
        }
    }
}

fn render_feed_panel(frame: &mut Frame, area: Rect, info: &FeedDisplayInfo, state: &FeedState) {
    let title = feed_block_title(info, state);
    let border_style = match state.health {
        FeedHealth::Alive => Style::default().fg(Color::Green),
        FeedHealth::Stale => Style::default().fg(Color::Yellow),
        FeedHealth::Error => Style::default().fg(Color::Red),
        FeedHealth::Waiting => {
            if info.mode == FeedMode::Disabled {
                Style::default().fg(Color::DarkGray).add_modifier(Modifier::DIM)
            } else {
                Style::default().fg(Color::DarkGray)
            }
        }
    };

    let block = Block::default()
        .title(title)
        .borders(Borders::ALL)
        .border_style(border_style);
    let inner = block.inner(area);
    frame.render_widget(block, area);

    let indicator = health_indicator(state.health);
    let status_text = Span::raw(format!(" {:<12}", state.status_text));

    let line1 = Line::from(vec![indicator, status_text]);

    let freq_span = Span::styled(
        format!("{:>7.1} Hz", state.frequency_hz),
        freq_style(state.health),
    );
    let packets_span = Span::raw(format!("   {:>8} packets", state.total_packets));
    let rate_span = Span::raw(format!("   {:>7.1} KB/s", state.data_rate_kb_s));
    let ago_span = Span::raw(format!("   last: {:>8}", format_ago(state.last_packet_ago_secs)));

    let line2 = Line::from(vec![freq_span, packets_span, rate_span, ago_span]);

    let mut lines = vec![line1, line2];

    if let Some(ref frame) = state.last_frame {
        let speed_span = Span::styled(
            format!(" {:>6.0} km/h", frame.speed_kmh),
            Style::default().fg(Color::White).add_modifier(Modifier::BOLD),
        );
        let gear_span = Span::styled(
            format!("  Gear:{}", frame.gear_display()),
            Style::default().fg(Color::Yellow),
        );
        let rpm_span = Span::raw(format!("  {:.0} RPM", frame.engine_rpm));
        let lap_span = Span::raw(format!("  Lap:{}", TelemetryFrame::format_lap_time(frame.lap_time_ms)));
        let line3 = Line::from(vec![speed_span, gear_span, rpm_span, lap_span]);
        lines.push(line3);

        let throttle_pct = (frame.throttle.clamp(0.0, 1.0) * 100.0) as u8;
        let brake_pct = (frame.brake.clamp(0.0, 1.0) * 100.0) as u8;
        let inputs_span = Span::raw(format!(" THR:{:>3}%  BRK:{:>3}%", throttle_pct, brake_pct));
        let pos_span = Span::raw(format!("  Pos:{:.3}", frame.spline_position));
        let line4 = Line::from(vec![inputs_span, pos_span]);
        lines.push(line4);
    }

    let paragraph = Paragraph::new(lines);
    frame.render_widget(paragraph, inner);
}

pub fn render(
    frame: &mut Frame,
    feeds: &[(FeedDisplayInfo, Arc<Mutex<FeedState>>)],
    session_dir: &str,
    version: &str,
) {
    let total_feeds = feeds.len() as u16;

    let outer = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(3),
            Constraint::Min(total_feeds * 4 + 2),
            Constraint::Length(3),
        ])
        .split(frame.area());

    let title_block = Block::default()
        .borders(Borders::ALL)
        .border_style(Style::default().fg(Color::Cyan));
    let title_inner = title_block.inner(outer[0]);
    frame.render_widget(title_block, outer[0]);

    let title_text = Line::from(Span::styled(
        format!(
            " rusty-telemetry v{} -- Telemetry Listener ",
            version
        ),
        Style::default()
            .fg(Color::Cyan)
            .add_modifier(Modifier::BOLD),
    ));
    let title_para = Paragraph::new(title_text);
    frame.render_widget(title_para, title_inner);

    let feed_constraints: Vec<Constraint> = feeds
        .iter()
        .map(|_| Constraint::Min(6))
        .collect();
    let feed_layout = Layout::default()
        .direction(Direction::Vertical)
        .constraints(feed_constraints)
        .split(outer[1]);

    for (i, (info, state)) in feeds.iter().enumerate() {
        // Clone inside the lock, then drop the guard before rendering
        // to avoid blocking the UDP receive task during the entire draw.
        let snapshot = state.lock().ok().map(|mut s| {
            s.tick();
            s.clone()
        });
        if let Some(snap) = snapshot {
            render_feed_panel(frame, feed_layout[i], info, &snap);
        }
    }

    let footer_block = Block::default()
        .borders(Borders::ALL)
        .border_style(Style::default().fg(Color::DarkGray));
    let footer_inner = footer_block.inner(outer[2]);
    frame.render_widget(footer_block, outer[2]);

    let footer_text = Line::from(vec![
        Span::styled(
            format!(" Session: {}/ ", session_dir),
            Style::default().fg(Color::White),
        ),
        Span::raw("   "),
        Span::styled(
            "Ctrl+C Quit".to_string(),
            Style::default().fg(Color::DarkGray),
        ),
    ]);
    let footer_para = Paragraph::new(footer_text).wrap(Wrap { trim: true });
    frame.render_widget(footer_para, footer_inner);
}