quadraui 0.6.0

//! TUI rasteriser for [`crate::RadioGroup`].
//!
//! Stacks each [`crate::RadioOption`] one per row, painting `(•) Label`
//! for the selected option and `( ) Label` for the rest — the same
//! bracket-glyph convention [`crate::tui::switch`] uses for its knob.
//! Each row is its own hit target, mirroring
//! [`crate::primitives::radio_group::RadioGroupLayout::hit_test`]'s
//! per-option resolution.

use ratatui::buffer::Buffer;
use ratatui::layout::Rect;

use super::{ratatui_color, set_cell};
use crate::primitives::radio_group::{
    RadioGroup, RadioGroupLayout, RadioOption, RadioOptionMeasure,
};
use crate::theme::Theme;

/// Compute the TUI cell-unit layout for a [`RadioGroup`] without
/// painting. Every option gets one full-width row, one cell tall —
/// [`RadioGroup::layout`]'s `measure` closure is fed a constant size
/// rather than any real text metrics (the TUI backend has no font to
/// measure against).
pub fn tui_radio_group_layout(group: &RadioGroup, area: Rect) -> RadioGroupLayout {
    let bounds = crate::event::Rect::new(
        area.x as f32,
        area.y as f32,
        area.width as f32,
        area.height as f32,
    );
    group.layout(bounds, |_option: &RadioOption| RadioOptionMeasure {
        width: bounds.width,
        height: 1.0,
    })
}

/// Draw a [`RadioGroup`] into `area` on `buf`, one row per option.
/// Returns the layout for host click dispatch.
pub fn draw_radio_group(
    buf: &mut Buffer,
    area: Rect,
    group: &RadioGroup,
    theme: &Theme,
) -> RadioGroupLayout {
    let layout = tui_radio_group_layout(group, area);

    if area.width == 0 || area.height == 0 {
        return layout;
    }

    for (index, option) in group.options.iter().enumerate() {
        let Some(row) = layout.items.get(index) else {
            continue;
        };
        if row.height <= 0.0 || row.width <= 0.0 {
            continue;
        }
        let y = row.y.round() as u16;
        let x0 = row.x.round() as u16;
        let w = row.width.round() as u16;
        let end = x0.saturating_add(w);
        let is_selected = group.selected == Some(index);

        let bg = if is_selected {
            ratatui_color(theme.selected_bg)
        } else {
            ratatui_color(theme.background)
        };
        let brk_fg = if option.disabled {
            ratatui_color(theme.muted_fg)
        } else if is_selected && group.focused {
            ratatui_color(theme.accent_fg)
        } else {
            ratatui_color(theme.border_fg)
        };
        let label_fg = if option.disabled {
            ratatui_color(theme.muted_fg)
        } else {
            ratatui_color(theme.foreground)
        };

        let glyph = if is_selected { '•' } else { ' ' };
        let text = format!("({glyph}) {}", option.label);
        let last_bracket_idx = 2usize; // '(', glyph, ')' — label starts after

        let mut col = x0;
        for (i, ch) in text.chars().enumerate() {
            if col >= end {
                break;
            }
            let fg = if i <= last_bracket_idx {
                brk_fg
            } else {
                label_fg
            };
            set_cell(buf, col, y, ch, fg, bg);
            col += 1;
        }
        while col < end {
            set_cell(buf, col, y, ' ', label_fg, bg);
            col += 1;
        }
    }

    layout
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::event::Point;
    use crate::primitives::radio_group::{RadioGroupHit, RadioOption};
    use crate::types::WidgetId;

    fn cell_char(buf: &Buffer, x: u16, y: u16) -> char {
        buf[(x, y)].symbol().chars().next().unwrap_or(' ')
    }

    fn mk_group() -> RadioGroup {
        RadioGroup::new(
            WidgetId::new("settings:theme"),
            vec![
                RadioOption::new(WidgetId::new("settings:theme:light"), "Light"),
                RadioOption::new(WidgetId::new("settings:theme:dark"), "Dark"),
            ],
        )
    }

    // Parametrized over the area's origin — LESSONS.md "Layout helpers
    // must return coords in the same frame across backends".
    // `tui_radio_group_layout` bakes `area.x`/`area.y` straight into
    // `RadioGroup::layout`'s returned bounds (absolute frame), so the
    // regression guard is a full paint+hit_test round trip re-run at a
    // non-zero origin.
    fn round_trip_at(origin_x: u16, origin_y: u16) {
        let area = Rect::new(origin_x, origin_y, 10, 2);
        let mut buf = Buffer::empty(area);
        let mut group = mk_group();
        group.selected = Some(1);
        group.focused = true;
        let layout = draw_radio_group(&mut buf, area, &group, &Theme::default());

        assert_eq!(cell_char(&buf, origin_x, origin_y), '(');
        assert_eq!(cell_char(&buf, origin_x + 1, origin_y), ' ');
        assert_eq!(cell_char(&buf, origin_x + 4, origin_y), 'L');

        assert_eq!(cell_char(&buf, origin_x, origin_y + 1), '(');
        assert_eq!(cell_char(&buf, origin_x + 1, origin_y + 1), '•');
        assert_eq!(cell_char(&buf, origin_x + 4, origin_y + 1), 'D');

        let hit = layout.hit_test(Point::new(origin_x as f32 + 1.0, origin_y as f32));
        assert_eq!(hit, RadioGroupHit::Option(0));
        let hit2 = layout.hit_test(Point::new(origin_x as f32 + 1.0, origin_y as f32 + 1.0));
        assert_eq!(hit2, RadioGroupHit::Option(1));
        let outside = layout.hit_test(Point::new(origin_x as f32 + 1.0, origin_y as f32 + 50.0));
        assert_eq!(outside, RadioGroupHit::Outside);
    }

    #[test]
    fn paint_and_hit_round_trip() {
        round_trip_at(0, 0);
    }

    #[test]
    fn paint_and_hit_round_trip_at_nonzero_origin() {
        round_trip_at(7, 13);
    }

    #[test]
    fn disabled_option_still_paints_but_dims() {
        let area = Rect::new(0, 0, 10, 2);
        let mut buf = Buffer::empty(area);
        let mut group = mk_group();
        group.options[1].disabled = true;
        draw_radio_group(&mut buf, area, &group, &Theme::default());
        assert_eq!(cell_char(&buf, 4, 1), 'D');
    }

    #[test]
    fn zero_size_is_a_no_op() {
        let buf_area = Rect::new(0, 0, 10, 2);
        let mut buf = Buffer::empty(buf_area);
        let group = mk_group();
        let _layout = draw_radio_group(&mut buf, Rect::new(0, 0, 0, 0), &group, &Theme::default());
        assert_eq!(cell_char(&buf, 0, 0), ' ');
    }
}