// State glyphs, drawn with cairo alone.
//
// The panel is monochrome, so shape is the only channel left and these four
// have to stay apart at 14 px. Kept free of St/Clutter/GNOME imports so the
// shapes can be rendered to a file and looked at, rather than guessed about.

/** Draw `state` filling the given box, in the colour passed as {r,g,b,a} 0..1. */
export function drawState(cr, state, width, height, color) {
    const { r, g, b, a } = color;
    const LINE = 1.75;
    const cx = width / 2;
    const cy = height / 2;
    // Centreline of the ring. A stroke straddles it, so a disc filled to this
    // radius reads visibly smaller than a ring drawn at it -- the filled states
    // below use `outer` instead, which keeps every glyph the same size.
    const radius = Math.min(width, height) / 2 - LINE;
    const outer = radius + LINE / 2;

    cr.setLineWidth(LINE);
    cr.setSourceRGBA(r, g, b, a);

    switch (state) {
    case 'blocked':
        // Disc inside a ring: the most ink of the four, for the only state
        // where a session is stuck until you act. The inner disc has to be
        // big enough to register at 14 px, or this reads as plain "working".
        cr.arc(cx, cy, radius, 0, 2 * Math.PI);
        cr.stroke();
        // 0.55 of the ring radius: below that the centre stops registering at
        // 14 px and this collapses into the "working" ring; above it the gap
        // closes and it collapses into the "waiting" disc. Checked by
        // rendering, not guessed.
        cr.arc(cx, cy, radius * 0.55, 0, 2 * Math.PI);
        cr.fill();
        break;
    case 'waiting':
        cr.arc(cx, cy, outer, 0, 2 * Math.PI);
        cr.fill();
        break;
    case 'busy':
        cr.arc(cx, cy, radius, 0, 2 * Math.PI);
        cr.stroke();
        break;
    default:
        // Idle: same ring as "working", but dashed and dimmed. Reading as a
        // fainter version of a state you already know is the point -- nobody
        // is waiting on it.
        cr.setDash([2, 2], 0);
        cr.setSourceRGBA(r, g, b, a * 0.5);
        cr.arc(cx, cy, radius, 0, 2 * Math.PI);
        cr.stroke();
        cr.setDash([], 0);
        break;
    }
}