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

use crate::state::{AppState, TimeItem};

const ACTIVE_COLOR: Color = Color::Green;
const INACTIVE_COLOR: Color = Color::Yellow;

pub fn render(frame: &mut Frame, state: &AppState) {
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Ratio(1, 3),
            Constraint::Ratio(1, 3),
            Constraint::Ratio(1, 3),
        ])
        .split(frame.size());

    render_section(
        frame,
        chunks[0],
        "Permanent Items",
        &state.permanent_items,
        state.current_pane == 0,
        state.selected_indices[0],
        state,
    );

    render_section(
        frame,
        chunks[1],
        "Recurring Items",
        &state.recurring_items,
        state.current_pane == 1,
        state.selected_indices[1],
        state,
    );

    render_section(
        frame,
        chunks[2],
        "Recent Items",
        &state.recent_items,
        state.current_pane == 2,
        state.selected_indices[2],
        state,
    );
}

fn render_section(
    frame: &mut Frame,
    area: Rect,
    title: &str,
    items: &[TimeItem],
    is_active: bool,
    selected: usize,
    state: &AppState,
) {
    let border_color = if is_active { ACTIVE_COLOR } else { INACTIVE_COLOR };
    
    let block = Block::default()
        .borders(Borders::ALL)
        .title(title)
        .style(Style::default().fg(border_color));

    let items: Vec<ListItem> = items
        .iter()
        .enumerate()
        .map(|(i, item)| {
            let is_running = state
                .active_timer
                .as_ref()
                .map(|(active, _)| active.name == item.name)
                .unwrap_or(false);

            let style = if is_running {
                Style::default().fg(ACTIVE_COLOR).add_modifier(Modifier::BOLD)
            } else if i == selected && is_active {
                Style::default().fg(border_color).add_modifier(Modifier::REVERSED)
            } else {
                Style::default()
            };

            let mut line = item.name.clone();
            if !item.tags.is_empty() {
                line.push_str(" [");
                line.push_str(&item.tags.join(", "));
                line.push(']');
            }

            ListItem::new(Line::from(vec![Span::styled(line, style)]))
        })
        .collect();

    let list = List::new(items).block(block);
    frame.render_widget(list, area);
}