/**
 * What colour a body is drawn in.
 *
 * Every body says `mate`: on the viewer's side or not. That is enough for a
 * game of two sides, and a game that sends nothing more looks exactly as it
 * always has. A game of three sides, or everybody for themselves, also sends
 * `side` — any string naming the body's side — and each side that is not the
 * viewer's gets its own colour from a small fixed palette.
 *
 * A side keeps the colour it was first given for as long as the page is
 * open, so it does not change hue between frames, or when another side walks
 * out of sight. The first side seen gets the enemy red a two-side game
 * already wears. More sides than the palette has wrap round to its start.
 *
 * Mates keep the mate colour, you keep yours and the dead keep their grey,
 * whatever side they are on: those are drawn by the callers, not here.
 */

/** Today's enemy, and what any body without a `side` wears. */
export const ENEMY = { skin: "#d8483f", dot: "#e35d5b", mark: "rgba(235,150,120,0.9)" };

/**
 * The palette, in the order sides are handed it. Each is `skin` in the first
 * person, `dot` on the map and `mark` for a last-seen outline. None is blue
 * (mates), grey (the dead) or white (you).
 */
export const PALETTE = [
  ENEMY,
  { skin: "#e08a2c", dot: "#f0a040", mark: "rgba(240,175,100,0.9)" },
  { skin: "#9b5fd6", dot: "#b07ae8", mark: "rgba(190,150,235,0.9)" },
  { skin: "#4fae4a", dot: "#62c45c", mark: "rgba(140,210,130,0.9)" },
  { skin: "#d655a8", dot: "#e86fbb", mark: "rgba(235,150,205,0.9)" },
  { skin: "#c9b52e", dot: "#ddc944", mark: "rgba(225,210,120,0.9)" },
];

/** A fresh book of which side has which colour. */
export const makeSides = () => new Map();

/** The one book the renderers share, so the map and the scene agree. */
const shared = makeSides();

/**
 * The colours for a body that is not on the viewer's side: by its `side`
 * when it carries one, today's enemy colours when it does not.
 */
export function enemyColours(body, book = shared) {
  const side = body.side;
  if (typeof side !== "string") return ENEMY;
  let at = book.get(side);
  if (at === undefined) {
    at = book.size % PALETTE.length;
    book.set(side, at);
  }
  return PALETTE[at];
}