use color::Rgba8;
use kiln_core::cp437::tile_to_char;
use kiln_core::glyph::Glyph;
use ratatui::layout::Rect;
use ratatui::prelude::Color;
use ratatui::style::Style;
use ratatui::text::Span;

/// Converts a core [`Rgba8`] color into a ratatui truecolor [`Color`].
///
/// The alpha channel is dropped — terminals have no per-cell alpha. Truecolor
/// requires terminal support; terminals limited to 256 colors approximate it.
pub fn rgba8_to_color(c: Rgba8) -> Color {
    Color::Rgb(c.r, c.g, c.b)
}

/// Converts a [`Glyph`] to a single-character styled [`Span`].
///
/// The tile index is mapped to a CP437 character; fg and bg are both applied.
pub fn glyph_to_span(glyph: Glyph) -> Span<'static> {
    let ch = tile_to_char(glyph.tile).to_string();
    let style = Style::default()
        .fg(rgba8_to_color(glyph.fg))
        .bg(rgba8_to_color(glyph.bg));
    Span::styled(ch, style)
}

/// Returns true if two `Rect`s share at least one cell.
pub fn rects_overlap(a: Rect, b: Rect) -> bool {
    a.x < b.x + b.width && b.x < a.x + a.width && a.y < b.y + b.height && b.y < a.y + a.height
}