RingBRP/tools/playthrough.mjs

/**
 * Play one encounter and read what happened, blow by blow.
 *
 * The lethality and focus guards print a number per creature, and a number cannot tell
 * you WHY a fight went the way it did. Three review-log entries in a row (R-258 to R-260)
 * were written from side harnesses that agreed with a number while modelling the wrong
 * fight. So this narrates the REAL `runFight` — the one the baselines are recorded from —
 * through its `say` hook, which reports decisions and never rolls. The narrated fight is
 * the same fight the guards measure, and check-lethality and check-focus both prove it by
 * still matching their baselines with the hook in place.
 *
 *   npm run play                                  the recorded pack, both targeting modes
 *   node tools/playthrough.mjs redcap             a named creature
 *   node tools/playthrough.mjs redcap 20260913    a chosen seed
 *   node tools/playthrough.mjs redcap 20260913 focus    one mode only
 *   node tools/playthrough.mjs --creature quiet_neighbours_npc --count 6 \\
 *     --party ashcroft,bhattacharya,renshaw,braithwaite,pollard,okonkwo --seed 11
 *                                     a scenario's own encounter, against its own cast
 *
 * The pack size comes from focus-baseline.json, so the fight you read is the fight
 * check-focus measures. Creatures it records as pinned — no pack size makes them an even
 * fight — are played solo, where targeting cannot mean anything anyway.
 */
import { readFileSync } from "node:fs";
import path from "node:path";
/* The whole population, through the one door. Reading NPCS from content.mjs meant
   this tool could only see the 47 creatures that happen to live in that file, so a
   creature from tools/bestiary-*.mjs was simply "not found". See check-seam.mjs. */
import { collectSpecs } from "./all-specs.mjs";
const NPCS = (await collectSpecs()).map(r => r.spec);
import { ROSTER } from "./roster.mjs";
import { runFight, makeRng } from "./simulate.mjs";

const ROOT = path.resolve(path.dirname(new URL(import.meta.url).pathname.replace(/^\/([A-Za-z]:)/, "$1")), "..");
const base  = JSON.parse(readFileSync(path.join(ROOT, "tools", "lethality-baseline.json"), "utf8"));
const focus = JSON.parse(readFileSync(path.join(ROOT, "tools", "focus-baseline.json"), "utf8"));

/* Flags mirror tools/simulate.mjs, so a fight measured there can be read here with the
   same words. The positional form still works: <key> <seed> <mode>. */
const argv = process.argv.slice(2);
const opt  = (n, d) => { const i = argv.indexOf(n); return i >= 0 ? argv[i + 1] : d; };
const positional = argv.filter((a, i) => !a.startsWith("--") && !(i > 0 && argv[i - 1].startsWith("--")));

const KEY  = opt("--creature", positional[0] ?? "redcap");
const SEED = Number(opt("--seed", positional[1] ?? 20260913));
const spec = NPCS.find(n => n.key === KEY);
if (!spec) {
  console.error(`playthrough: no creature keyed "${KEY}". Try one of: `
    + NPCS.slice(0, 6).map(n => n.key).join(", ") + ", ...");
  process.exit(1);
}
/* The frozen four by default — the party every recorded number is measured against — or a
   named cast, for reading a scenario's own encounter rather than the guard's. */
const partyKeys = (opt("--party", "") || "").split(",").map(x => x.trim()).filter(Boolean);
const party = (partyKeys.length ? partyKeys : base.party).map(k => {
  const found = ROSTER.find(r => r.key === k || r.key === "pc_" + k);
  if (!found) { console.error(`playthrough: "${k}" is not on the duty roster`); process.exit(1); }
  return found;
});
const rec = focus.creatures[KEY];
/* A pinned row records the pack size that was TRIED, not one worth playing: the header
   above promises solo for those, and a tool that contradicts its own documentation is the
   defect this file exists to help find. Solo also matches what check-lethality records. */
const N = Number(opt("--count", 0)) || (rec?.gain !== undefined ? rec.n : 1);

/* THE generator the guards use, not merely one of the same shape. A seed here names the
   first fight of `simulate.mjs --seed <n>` exactly. */
const mk = makeRng;
const firstName = c => (c.name ?? "?").split(" ")[0];
const hp = c => `${Math.max(0, c.hp)}/${c.hpMax}`;

function play(mode) {
  /* Identical creatures need telling apart or the log is unreadable: A, B, C in the order
     they first do something. */
  const tag = new Map();
  const nameOf = c => {
    if (c.side === "party") return firstName(c);
    if (!tag.has(c)) tag.set(c, `${spec.name} ${String.fromCharCode(65 + tag.size)}`);
    return tag.get(c);
  };
  const lines = [];
  const say = e => {
    if (e.kind === "round") {
      lines.push(`\nROUND ${e.round}  —  ${e.enemy.filter(x => x.hp > 0).length} of ${N} still up`);
      return;
    }
    if (e.kind === "turn") return;
    if (e.kind === "grounded") {
      lines.push(`  >> ${nameOf(e.defender)} COMES DOWN — it is a ${e.plan} now.`
        + ` Hide ${e.hide} everywhere, ${e.vital} on the chest, and the wings are gone.`);
      return;
    }
    const a = nameOf(e.attacker), d = nameOf(e.defender);
    if (e.kind === "stopped") {
      lines.push(`  ${a} → ${d}: ${e.roll} ${e.level.toUpperCase()} · ${e.location?.id ?? "?"}`
        + ` · ${e.rolled} vs armour ${e.armour}${e.effectiveArmour !== e.armour ? `→${e.effectiveArmour}` : ""}`
        + ` — stopped dead`);
      return;
    }
    if (e.kind === "miss")
      lines.push(`  ${a} → ${d}: ${e.roll} vs ${e.target} — ${e.level}`);
    else if (e.kind === "dodged")
      lines.push(`  ${a} → ${d}: ${e.roll} ${e.level.toUpperCase()} — dodged`
        + ` (${e.dodgeRoll} vs ${e.dodgeTarget}${e.penalty ? `, ${e.penalty} for defences already spent` : ""})`);
    else if (e.kind === "hit")
      lines.push(`  ${a} → ${d}: ${e.roll} ${e.level.toUpperCase()}${e.landing !== e.level ? ` → lands ${e.landing}` : ""}`
        + ` · ${e.location?.id ?? "?"} · ${e.rolled} vs armour ${e.armour}${e.effectiveArmour !== e.armour ? `→${e.effectiveArmour}` : ""}`
        + ` = ${e.taken} · ${d} ${hp(e.defender)}`
        + `${e.majorWound ? " · MAJOR WOUND" : ""}${e.destroyed ? " · DESTROYED" : e.disabled ? " · disabled" : ""}`
        + `${e.defender.hp <= 0 ? "  ** DOWN **" : ""}`);
  };
  const r = runFight(mk(SEED), party, Array(N).fill(spec), { partyTargets: mode, say });
  return { r, lines };
}

const MODE = opt("--mode", positional[2]);
const MODES = MODE ? [MODE] : (N > 1 ? ["random", "focus"] : ["random"]);
for (const mode of MODES) {
  const { r, lines } = play(mode);
  const how = N === 1 ? "" : mode === "focus" ? "  —  party CONCENTRATING FIRE"
                                              : "  —  party picking targets at random";
  console.log(`\n${"=".repeat(78)}\n${N} × ${spec.name.toUpperCase()}${how}\n${"=".repeat(78)}`);
  console.log(lines.join("\n"));
  console.log(`\n  → [${N > 1 ? mode : "solo"}] ${r.won ? "PARTY WINS" : r.wiped ? "PARTY WIPED" : "neither side finished it"}`
    + ` in ${r.rounds} rounds · ${r.partyDown} of ${party.length} down · ${r.dead} dead`);
}

if (rec?.gain !== undefined)
  console.log(`\nrecorded by check-focus over ${focus.runs} fights × ${focus.seeds.length} seeds:`
    + ` spread ${rec.spread}% · focus ${rec.focus}% · concentrating fire is worth ${rec.gain} points`);
else if (rec?.pinned !== undefined)
  console.log(`\ncheck-focus records this one as pinned at ${rec.pinned}% — no pack size makes it`
    + ` an even fight, so it is played solo here.`);