//! Status bar rendering for the TUI — modern segmented bar design.
//!
//! Flow: `draw_status_bar` reads live connection/turn state off
//! `AppStateRest` every frame and paints a single-line bar at the
//! bottom of the screen with three visual segments:
//!   [app name + status badge]  [spinner + info]  [provider · model · tokens]
//!
//! Design: the status bar uses a dark background with carefully
//! spaced segments so information is scannable at a glance.

use ratatui::layout::Rect;
use ratatui::style::{Style, Modifier};
use ratatui::text::{Line, Span};
use ratatui::widgets::Block;
use ratatui::Frame;
use super::theme::Theme;

/// Render the single-line status bar.
///
/// Layout (left-to-right, space-filling):
///   LEFT:   [zesdex] + status indicator (READY/PROG/NOAPI)
///   CENTER: spinner + optional contextual info
///   RIGHT:  provider · model · ↑tokens_in ↓tokens_out
pub fn draw_status_bar(frame: &mut Frame, area: Rect, state: &crate::app::state::rest::AppStateRest) {
    let spinner_frames = ["⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"];

    // ── Agent status badge ────────────────────────────────────────────────
    let (status_text, badge_bg, status_fg) = if state.turn_in_flight() {
        let f = spinner_frames[(state.misc.tick_count as usize / 2) % spinner_frames.len()];
        (format!(" {} PROG ", f), Theme::MODE_YOLO, Theme::BG)
    } else if state.misc.api_connected {
        (" READY ".to_string(), Theme::MODE_AUTO, Theme::BG)
    } else {
        (" NOAPI ".to_string(), Theme::TEXT_DIM, Theme::BG)
    };

    let status_badge = Span::styled(
        status_text,
        Style::default()
            .fg(status_fg)
            .bg(badge_bg)
            .add_modifier(Modifier::BOLD),
    );

    // ── Left segment: app name ────────────────────────────────────────────
    let left_spans = vec![
        Span::styled(
            " ⚡zesdex ",
            Style::default()
                .fg(Theme::TEXT)
                .add_modifier(Modifier::BOLD),
        ),
        status_badge,
    ];

    // ── Right segment: metadata ───────────────────────────────────────────
    let right_str = if let Some(ref rt) = state.session_runtime {
        let max_tokens = state.app_config.model_roles.values()
            .find(|role| role.provider == state.settings.provider && role.model == state.settings.model)
            .and_then(|role| role.context_window);

        let total_chars: usize = rt.messages.iter()
            .filter_map(|m| m.content.as_deref())
            .map(|c| c.len())
            .sum();
        let current_tokens = total_chars / 4;

        let mut parts = Vec::new();
        if rt.usage.last_tokens_in > 0 || rt.usage.last_tokens_out > 0 {
            parts.push(format!("↑{} ↓{}", rt.usage.last_tokens_in, rt.usage.last_tokens_out));
        }
        let max_str = max_tokens.map(|v| v.to_string()).unwrap_or_else(|| "?".to_string());
        parts.push(format!("{}/{}", current_tokens, max_str));
        parts.push(state.settings.provider.clone());
        parts.push(state.settings.model.clone());

        format!(" {} ", parts.join(" · "))
    } else {
        let max_tokens = state.app_config.model_roles.values()
            .find(|role| role.provider == state.settings.provider && role.model == state.settings.model)
            .and_then(|role| role.context_window);
        let max_str = max_tokens.map(|v| v.to_string()).unwrap_or_else(|| "?".to_string());
        format!(" 0/{} · {} · {} ", max_str, state.settings.provider, state.settings.model)
    };

    // ── Combine everything ────────────────────────────────────────────────
    let left_line = Line::from(left_spans);

    let right_line = Line::from(Span::styled(
        right_str,
        Style::default().fg(Theme::TEXT_MUTED),
    ));

    // Render the bar using two columns
    use ratatui::layout::{Constraint, Direction, Layout};
    let chunks = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Length(25),
            Constraint::Min(10),
        ])
        .split(area);

    let block = Block::default()
        .style(
            Style::default()
                .bg(Theme::STATUS_BAR_BG)
                .fg(Theme::TEXT),
        );

    // Left part
    let left_para = ratatui::widgets::Paragraph::new(left_line).block(block.clone());
    frame.render_widget(left_para, chunks[0]);

    // Right part
    let right_para = ratatui::widgets::Paragraph::new(right_line)
        .block(block)
        .alignment(ratatui::layout::Alignment::Right);
    frame.render_widget(right_para, chunks[1]);
}