// Pure, seeded crew generation — no DB, no Date, no Math.random. Same seed → same starting
// crew; the exploration crew roll draws from the caller's per-planet rng stream so a found
// member is deterministic per save+planet (same derivation as the resource/part haul).

import { mulberry32 } from './world'

export interface CrewMember {
  name: string
  role: string
  traitGood: string
  traitBad: string
}

const FIRST_NAMES = [
  'AVA', 'BEN', 'CASS', 'DANA', 'ELI', 'FERN', 'GIDEON', 'HALYA',
  'IVAR', 'JUNO', 'KAI', 'LORE', 'MARA', 'NICO', 'ODESSA', 'PETRA',
]

const LAST_NAMES = [
  'VANCE', 'OKONKWO', 'SORENSEN', 'DELACRUZ', 'HALLOWAY', 'IBARRA', 'KOVAC', 'LINDQVIST',
  'MERCER', 'NADEAU', 'ORLOV', 'QUINTANA', 'REYES', 'STALKE', 'TANAKA', 'UNDERWOOD',
  'VALDEZ', 'WHITLOCK', 'YAMADA', 'ZUBEROV', 'ASHFORD', 'BLACKWELL',
]

const ROLES = ['COMMANDER', 'PILOT', 'ENGINEER', 'MEDIC', 'NAVIGATOR', 'SCIENTIST', 'GUNNER', 'TECHNICIAN']

const GOOD_TRAITS = [
  'STEADY UNDER PRESSURE', 'RECKLESS COURAGE', 'CALM IN A CRISIS', 'FIXES ANYTHING',
  'SHARP SHOOTER', 'READS STARS BLIND', 'QUICK HANDS', 'IRON WILL',
  'FINDS HIDDEN THINGS', 'TALKS TO ANYONE',
]

const BAD_TRAITS = [
  'RIGID — SLOW TO ADAPT', 'SHORT FUSE', 'OVERCAUTIOUS', 'CARELESS WITH FUSES',
  'SLOWS THE CREW DOWN', 'ARGUES WITH EVERYONE', 'FORGETS TO EAT', 'JINXED IN A DOGFIGHT',
  'HOARDS RATIONS', 'DOUBTS THE CAPTAIN',
]

const STARTING_CREW_MIN = 2
const STARTING_CREW_SPREAD = 2 // 2..3 starting members
export const CREW_CHANCE = 0.18 // a scan finds a crew member who joins the ship (~1 in 5-6 scans)

function title(word: string): string {
  return word.charAt(0) + word.slice(1).toLowerCase()
}

function pick<T>(rng: () => number, arr: T[]): T {
  return arr[Math.floor(rng() * arr.length)]
}

// A name unique against `taken` (the current roster), claimed into the set on success.
// The pool is finite (16×22=352) and the roster has no cap, so — like makeName — fall back to
// numbered variants once every base is taken instead of spinning forever.
export function makeCrewName(rng: () => number, taken: Set<string>): string {
  for (;;) {
    const base = `${title(pick(rng, FIRST_NAMES))} ${pick(rng, LAST_NAMES)}`
    if (!taken.has(base)) {
      taken.add(base)
      return base
    }
    if (taken.size >= FIRST_NAMES.length * LAST_NAMES.length) {
      for (let n = 2; ; n++) {
        const name = `${base} ${n}`
        if (!taken.has(name)) {
          taken.add(name)
          return name
        }
      }
    }
  }
}

// The crew a new game starts with: 2–3 members, unique names and roles (roles are drawn
// without replacement). Pure — the caller derives the rng from the save seed.
export function generateStartingCrew(rng: () => number): CrewMember[] {
  const taken = new Set<string>()
  const roles = [...ROLES]
  const crew: CrewMember[] = []
  for (let i = 0; i < STARTING_CREW_MIN + Math.floor(rng() * STARTING_CREW_SPREAD); i++) {
    const role = roles.splice(Math.floor(rng() * roles.length), 1)[0]
    crew.push({ name: makeCrewName(rng, taken), role, traitGood: pick(rng, GOOD_TRAITS), traitBad: pick(rng, BAD_TRAITS) })
  }
  return crew
}

// The exploration crew roll: with CREW_CHANCE a member is found and joins the ship. Draws
// from the SAME per-planet rng stream as the resource/part haul (called after it in
// save.ts), so the outcome stays deterministic per save+planet. `taken` is the current
// roster's names, keeping every name on the ship unique.
export function rollCrewMember(rng: () => number, taken: Set<string>): CrewMember | null {
  if (rng() >= CREW_CHANCE) return null
  const role = pick(rng, ROLES)
  return { name: makeCrewName(rng, taken), role, traitGood: pick(rng, GOOD_TRAITS), traitBad: pick(rng, BAD_TRAITS) }
}

// Independent PRNG stream for the starting crew of one save (same pattern as bodyRng /
// explorationRng in world.ts — a fixed offset keeps it away from every other derivation).
export function startingCrewRng(seed: string): () => number {
  return mulberry32((Number(seed) + 0x51ed270b) >>> 0)
}