/**
 * One line of advice, in the player's own words.
 *
 * A pure function of the snapshot the server sent plus two things the client
 * works out from the map it was given: whether you are standing on a site,
 * and whether you are within reach of the spike. Never more than one prompt —
 * the most urgent thing wins, because two instructions at once is none.
 */

/** Within this many units the server lets you pick up, plant or defuse. */
export const REACH = 46;

const secs = (n) => Math.max(0, Math.ceil(n));

export function choosePrompt(snap, world = {}) {
  if (!snap) return "";
  const me = snap.me;
  const spike = snap.spike;
  const onSite = world.onSite === true;
  const nearSpike = world.nearSpike === true;

  if (snap.phase === "over") return snap.result ? `Match over — ${snap.result}` : "Match over";
  if (me.blind > 0.05) return "You are blind — back off until it clears";
  if (!me.alive)
    return snap.phase === "buy"
      ? "Buy phase — you are back next round"
      : "Waiting for the next round — you're in it";
  if (snap.phase === "end") return snap.result ? `${snap.result} — next round in ${secs(snap.clock)}s` : "Round over";
  if (snap.phase === "buy")
    return `Buy phase — ${secs(snap.clock)}s left. Click a gun you can afford.`;

  if (me.planting > 0) return `Planting — hold F for ${secs(4 - me.planting)}s more`;
  if (spike.planted) {
    if (me.side === "def") {
      if (spike.defuse > 0) return `Defusing — keep holding F, ${secs(7 - spike.defuse)}s`;
      return nearSpike
        ? `Spike down, ${secs(spike.fuse)}s — hold F to defuse`
        : `Spike down, ${secs(spike.fuse)}s — get to it and hold F`;
    }
    return `Spike down, ${secs(spike.fuse)}s — keep them off it`;
  }

  if (me.side === "atk") {
    if (me.spike) return onSite ? "Hold F to plant" : "You have the spike — get to site A or B";
    if (spike.carried) return "Your team has the spike — go with them and take a site";
    if (nearSpike) return "Walk onto the spike to pick it up";
    return "Somebody has to carry the spike — it is on the ground";
  }
  return `Defending — hold A and B, ${secs(snap.clock)}s`;
}