mecha10-cli 0.6.3

//! Shared layout and footer helpers for the ratatui-based TUI screens.
//!
//! Several TUIs in this module (dev mode, teleop, topics list, topology,
//! init wizard, diagnostics) render an outer frame that always splits into
//! a main content area and a 3-row footer, and several of them render that
//! footer as a row of `key: label` keybinding hints with identical styling.
//! These helpers keep that shared structure defined in one place instead of
//! being rebuilt (byte-for-byte) in every `draw()`/`draw_footer()`.

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

/// Split a full-frame area into `(content_area, footer_area)` using the
/// standard `[Constraint::Min(10), Constraint::Length(3)]` vertical layout
/// shared by every TUI screen in this module.
pub fn standard_tui_layout(area: Rect) -> (Rect, Rect) {
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Min(10),   // Main content area
            Constraint::Length(3), // Footer
        ])
        .split(area);

    (chunks[0], chunks[1])
}

/// Split an area horizontally into a 60%/40% main panel + sidebar, the
/// layout shared by `DevModeTui` and `TeleopUi`.
pub fn main_and_sidebar_layout(area: Rect) -> (Rect, Rect) {
    let chunks = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage(60), // Main panel
            Constraint::Percentage(40), // Sidebar
        ])
        .split(area);

    (chunks[0], chunks[1])
}

/// Split an area horizontally into two panels using the given left-panel
/// percentage (the right panel gets the remainder), the layout shared by
/// `TopologyTui` (30/70 nav/details) and `TopicsListTui` (40/60 topics/messages).
pub fn two_panel_layout(area: Rect, left_percent: u16) -> (Rect, Rect) {
    let chunks = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage(left_percent),
            Constraint::Percentage(100 - left_percent),
        ])
        .split(area);

    (chunks[0], chunks[1])
}

/// Render a footer bar of `key: label` keybinding hints, styled consistently
/// across TUIs: bordered with a dark gray border, each key bold and colored,
/// each label a plain span, pairs separated by two spaces.
///
/// `hints` is a list of `(key, label, color)` triples, where `color` is the
/// color of the key (e.g. `("Q/ESC", "Exit", Color::Red)`).
pub fn render_footer_hints(f: &mut Frame, area: Rect, hints: &[(&str, &str, Color)]) {
    let mut spans = vec![Span::raw("  ")];

    for (i, (key, label, color)) in hints.iter().enumerate() {
        spans.push(Span::styled(
            format!("{}:", key),
            Style::default().fg(*color).add_modifier(Modifier::BOLD),
        ));

        let trailing = if i + 1 == hints.len() { "" } else { "  " };
        spans.push(Span::raw(format!(" {}{}", label, trailing)));
    }

    let footer = Paragraph::new(vec![Line::from(spans)]).block(
        Block::default()
            .borders(Borders::ALL)
            .border_style(Style::default().fg(Color::DarkGray)),
    );

    f.render_widget(footer, area);
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn standard_tui_layout_splits_content_and_footer() {
        let area = Rect::new(0, 0, 100, 40);
        let (content, footer) = standard_tui_layout(area);

        assert_eq!(footer.height, 3);
        assert_eq!(content.height, 37);
        assert_eq!(content.y, 0);
        assert_eq!(footer.y, 37);
    }

    #[test]
    fn two_panel_layout_splits_by_given_percentage() {
        let area = Rect::new(0, 0, 100, 40);
        let (left, right) = two_panel_layout(area, 30);

        assert_eq!(left.width, 30);
        assert_eq!(right.width, 70);
        assert_eq!(left.x, 0);
        assert_eq!(right.x, 30);
    }

    #[test]
    fn two_panel_layout_matches_main_and_sidebar_at_60_40() {
        let area = Rect::new(0, 0, 100, 40);
        let (left, right) = two_panel_layout(area, 60);
        let (expected_main, expected_sidebar) = main_and_sidebar_layout(area);

        assert_eq!((left.width, left.x), (expected_main.width, expected_main.x));
        assert_eq!((right.width, right.x), (expected_sidebar.width, expected_sidebar.x));
    }
}