// Special-status registry (v0.37.0, ISS-073) — data-driven package modifiers: one entry per
// special status maps to reward/deadline/reputation tweaks applied at generation and delivery.
// Adding or removing a special is an edit of ONE entry here — no scattered branches elsewhere.
import type { Rng } from './seed';

export interface SpecialModifiers {
  // Multiplier on the base reward (applied at package generation).
  rewardMultiplier: number;
  // Scale factor on the drawn deadline window (applied at generation; forced offsets skip it).
  deadlineScale: number;
  // Flat reputation bonus added to the distance-based gain at delivery.
  repBonus: number;
}

export const SPECIALS: Record<string, SpecialModifiers> = {
  priority: {
    rewardMultiplier: 1.5, // ponytail: balance-tunable — a 50% premium for the tighter deadline below
    deadlineScale: 0.5, // ponytail: balance-tunable — half the normal 6–72h window (3–36h)
    repBonus: 0.5, // ponytail: balance-tunable — flat rep on top of the distance-based gain at delivery
  },
};

// Fraction of generated packages that roll a special status (v0.37.0).
export const SPECIAL_SPAWN_CHANCE = 0.15;

// Pure spawn helper: one chance draw, then a uniform pick among the registry's keys. The registry
// is a PARAM defaulting to the real one so tests can pass a filtered/empty record — removing an
// entry cleanly disables that status (an empty registry consumes no draws at all).
export function pickSpecial(rng: Rng, registry: Record<string, SpecialModifiers> = SPECIALS): string | null {
  const keys = Object.keys(registry);
  if (keys.length === 0) return null;
  if (rng() >= SPECIAL_SPAWN_CHANCE) return null;
  return keys[Math.floor(rng() * keys.length)];
}