RingBRP/tools/forge.mjs

/**
 * The forge, at the command line.
 *
 * The derivation is in ../forge.mjs, at the root and under the same law as rules.mjs:
 * pure, no Foundry, no catalogues. This file is the part that cannot be pure — it holds
 * the catalogues, validates the result against creature-schema, and formats a spec as
 * source. Part 5's in-Foundry panel imports the same derivation, which is the only way
 * to guarantee rather than hope that the two agree.
 *
 *   node tools/forge.mjs new --role brute --size large --tier 4
 *   node tools/forge.mjs new --role flyer --body winged --seed 7 --name "The martlet"
 *   node tools/forge.mjs explain --role lurker --size huge --tier 5
 *   node tools/forge.mjs measure --role brute --size large --tier 4
 *   node tools/forge.mjs list
 *
 * `new` prints the spec as source, formatted the way tools/bestiary-*.mjs are written,
 * so it can be pasted into one. It VALIDATES BEFORE PRINTING: a forge that emits
 * something check-creatures would reject has wasted the reader's time and taught them to
 * distrust the tool.
 *
 * `measure` runs it against the party check-lethality freezes, because "is this thing
 * too dangerous" is the question a GM actually has, and this repository answers questions
 * like that with a number rather than an adjective.
 */
import { forgeCreature, SIZE_BANDS, CREATURE_ROLES, FORGE_TIERS } from "../forge.mjs";
import { validate } from "./creature-schema.mjs";
import { WEAPONS } from "./content.mjs";
import { ROSTER } from "./roster.mjs";
import { measure, seedFor } from "./simulate.mjs";

const WEAPON_BY_KEY = new Map(WEAPONS.map(w => [w.key, w]));
/* The natural attacks are the ones that declare which bodies can make them; a rifle
   declares nothing because holding a rifle is a question about hands, not about the
   rifle. That declaration is also what makes this list derivable rather than typed. */
const NATURAL = WEAPONS.filter(w => Array.isArray(w.plans)).map(w => w.key);
const catalogues = {
  hasWeapon: k => WEAPON_BY_KEY.has(k),
  plansFor: k => WEAPON_BY_KEY.get(k)?.plans ?? null,
  naturalAttacks: NATURAL
};

const argv = process.argv.slice(2);
const cmd = argv[0] ?? "help";
const opt = (name, dflt) => {
  const i = argv.indexOf(`--${name}`);
  return i === -1 || !argv[i + 1] || argv[i + 1].startsWith("--") ? dflt : argv[i + 1];
};

function options() {
  return {
    key: opt("key", null), name: opt("name", null),
    species: opt("species", "baseline"), bodyPlan: opt("body", null),
    size: opt("size", "medium"), role: opt("role", "hunter"),
    tier: Number(opt("tier", 3)), seed: Number(opt("seed", 1))
  };
}

/** A spec as source, in the shape the bestiary files are written in. */
function asSource(spec) {
  const q = s => JSON.stringify(s);
  const ch = Object.entries(spec.ch).map(([k, v]) => `${k}: ${v}`).join(", ");
  const skills = spec.skills
    .map(s => `{fam:${q(s.fam)},spec:${q(s.spec)},val:${s.val}}`)
    .join(",\n             ");
  return `  { key: ${q(spec.key)}, name: ${q(spec.name)}, role: ${q(spec.role)},\n`
    + `    naturalArmour: ${spec.naturalArmour}, species: ${q(spec.species)}, bodyPlan: ${q(spec.bodyPlan)},\n`
    + `    ch: { ${ch} },\n`
    + `    skills: [${skills}],\n`
    + `    weapons: [${spec.weapons.map(q).join(", ")}],\n`
    + `    tactics: ${q(spec.tactics)} },`;
}

function forgeOrDie() {
  const { spec, trace, problems } = forgeCreature(options(), catalogues);
  if (problems.length) {
    console.error("forge: cannot derive that creature");
    for (const p of problems) console.error("  " + p);
    process.exit(1);
  }
  /* Validated before it is shown, never after. */
  const bad = validate(spec);
  if (bad.length) {
    console.error(`forge: derived a spec that creature-schema rejects — this is a bug in `
      + `forge.mjs, not in the request`);
    for (const p of bad) console.error("  " + (p.message ?? JSON.stringify(p)));
    process.exit(1);
  }
  return { spec, trace };
}

if (cmd === "list") {
  console.log("roles");
  for (const [k, r] of Object.entries(CREATURE_ROLES)) console.log(`  ${k.padEnd(9)} ${r.blurb}`);
  console.log("\nsizes");
  for (const [k, b] of Object.entries(SIZE_BANDS)) console.log(`  ${k.padEnd(9)} SIZ ${String(b.siz.join("–")).padEnd(7)} ${b.note}`);
  console.log("\ntiers");
  for (const [k, t] of Object.entries(FORGE_TIERS)) {
    console.log(`  ${k}  ${t.label.padEnd(10)} skills ${String(t.skill.join("–")).padEnd(7)} hide ${t.armourBase}`);
    console.log(`     ${t.worth}`);
  }
} else if (cmd === "new") {
  const { spec } = forgeOrDie();
  console.log(asSource(spec));
} else if (cmd === "explain") {
  const { spec, trace } = forgeOrDie();
  console.log(`${spec.name}  (${spec.key})`);
  console.log(`${spec.role}\n`);
  for (const t of trace) {
    console.log(`  ${String(t.field).padEnd(22)} ${String(t.value).padEnd(26)} ${t.because}`);
  }
} else if (cmd === "measure") {
  const { spec } = forgeOrDie();
  const PARTY = ["pc_holloway", "pc_okonkwo", "pc_nkemdirim", "pc_ferriby"];
  const party = PARTY.map(k => ROSTER.find(r => r.key === k)).filter(Boolean);
  const runs = Number(opt("runs", 1000));
  const r = measure(party, [spec], { runs, seed: seedFor(11, spec.key) });
  console.log(`${spec.name} — ${runs} runs against ${PARTY.map(k => k.slice(3)).join(", ")}`);
  console.log(`  party wiped      ${(r.wipeRate * 100).toFixed(1)}%`);
  console.log(`  agents killed    ${r.deathsPerRun.toFixed(2)} per fight`);
  console.log(`  creature killed  ${(r.winRate * 100).toFixed(1)}% of fights`);
} else {
  console.log(`forge — derive a creature, and say which rule produced each number

  node tools/forge.mjs new      --role brute --size large --tier 4
  node tools/forge.mjs explain  --role lurker --size huge --tier 5
  node tools/forge.mjs measure  --role flyer --body winged --tier 3
  node tools/forge.mjs list

  --role --size --tier 1-5 --species --body --seed --name --key --runs`);
}