// TURNCRAFT multiplayer relay — one shared booth.
//
// A deliberately small WebSocket room server: relays player positions,
// voxel edits, quest repairs and platter states; keeps the authoritative
// world-diff so late joiners see the same booth; persists it to disk.
//
// Run:  node relay.mjs            (PORT=8433 HOST=127.0.0.1 by default)
// Prod: bind 127.0.0.1 behind an nginx `location /turncraft/ws` proxy.

import { WebSocketServer } from 'ws';
import { readFileSync, writeFileSync, renameSync, existsSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import path from 'node:path';

const PORT = Number(process.env.PORT ?? 8433);
const HOST = process.env.HOST ?? '127.0.0.1';

// Mirrors src/core/constants.ts (server is standalone by design).
const WORLD = { x: 448, y: 160, z: 256 };
const MAX_BLOCK_ID = 30;
const NODES = new Set(['stylus', 'rca', 'crossfader', 'fuse', 'power']);

// Limits (ship-check): bounded room, bounded frames, bounded rates.
const MAX_PEERS = 24;
const MAX_FRAME_BYTES = 2048;
const MAX_MSGS_PER_SEC = 40;
const MAX_NAME_LEN = 24;
// Social & Reset Ritual limits: emotes and avatar churn are per-peer rate
// limited (drop, never queue) or the booth becomes hell; reset is global.
const EMOTE_COOLDOWN_MS = 4000;   // 1 airhorn/wave per 4 s per peer
const AVATAR_COOLDOWN_MS = 2000;  // 1 avatar change per 2 s per peer
const RESET_COOLDOWN_MS = 10 * 60_000; // anti-grief: 10 min since the win
const AVATAR_RANGES = { hue: 12, gear: 5, face: 4 }; // enum sizes (0..n-1)
const EMOTE_KINDS = 4;            // 0..3 = wave | nod | point | airhorn
// Grief ceiling: the diff map must stay bounded (18M voxels × ~30B/entry
// would be ~550MB if a bot painted the whole booth). ~400k edits ≈ 25MB.
const MAX_EDITS = 400_000;
const ALLOWED_ORIGINS = [
  /^https:\/\/([a-z0-9-]+\.)?partly\.party$/,
  /^https?:\/\/localhost(:\d+)?$/,
  /^https?:\/\/127\.0\.0\.1(:\d+)?$/,
];

const STATE_FILE = path.join(path.dirname(fileURLToPath(import.meta.url)), 'booth-state.json');

// ---- room state --------------------------------------------------------
/** edits: "x,y,z" -> blockId (the diff against the generated booth) */
const edits = new Map();
const repaired = new Set();
const platters = { A: { playing: false, rpm: 33 }, B: { playing: false, rpm: 33 } };
let workshop = null; // last-write-wins Headshell Workshop assembly state (or null)
let dirty = false;
/** ms epoch of the last win — gates the reset cooldown. 0 = "long ago". */
let winAt = 0;

/** Clamp an avatar to bounded ints; returns a clean copy (defaults on garbage). */
function validAvatar(a) {
  const pick = (v, n) => (Number.isInteger(v) && v >= 0 && v < n ? v : 0);
  if (!a || typeof a !== 'object') return { hue: 0, gear: 0, face: 0 };
  return {
    hue: pick(a.hue, AVATAR_RANGES.hue),
    gear: pick(a.gear, AVATAR_RANGES.gear),
    face: pick(a.face, AVATAR_RANGES.face),
  };
}

/**
 * The workshop's post-reset pose: assembled-but-undone. The fun parts replay
 * (wires, screws, balance); the tedium (finding + seating the cart) doesn't.
 */
function resetWorkshopPose() {
  return {
    cartSeated: true,
    cartRotation: 0,                 // already square — re-seating isn't the fun part
    wires: [null, null, null, null], // all four popped off: re-crimp them
    screws: [0.5, 0.5],
    weightNotch: 3 + Math.floor(Math.random() * 4), // random 3..6 — re-balance it
    tested: false,
  };
}

/** Validate + clamp a Headshell Workshop state; return a clean copy or null. */
function validWorkshop(s) {
  if (!s || typeof s !== 'object') return null;
  if (typeof s.cartSeated !== 'boolean' || typeof s.tested !== 'boolean') return null;
  if (![0, 1, 2, 3].includes(s.cartRotation)) return null;
  if (!Array.isArray(s.wires) || s.wires.length !== 4) return null;
  const wires = [];
  for (const w of s.wires) {
    if (w === null || [0, 1, 2, 3].includes(w)) wires.push(w);
    else return null;
  }
  if (!Array.isArray(s.screws) || s.screws.length !== 2) return null;
  if (!s.screws.every((v) => typeof v === 'number' && Number.isFinite(v))) return null;
  if (typeof s.weightNotch !== 'number' || !Number.isFinite(s.weightNotch)) return null;
  const cl = (v) => (v < 0 ? 0 : v > 1 ? 1 : v);
  return {
    cartSeated: s.cartSeated,
    cartRotation: s.cartRotation,
    wires,
    screws: [cl(s.screws[0]), cl(s.screws[1])],
    weightNotch: Math.max(0, Math.min(10, Math.round(s.weightNotch))),
    tested: s.tested,
  };
}

function loadState() {
  if (!existsSync(STATE_FILE)) return;
  try {
    const s = JSON.parse(readFileSync(STATE_FILE, 'utf8'));
    for (const [k, v] of s.edits ?? []) edits.set(k, v);
    for (const n of s.repaired ?? []) if (NODES.has(n)) repaired.add(n);
    Object.assign(platters.A, s.platters?.A ?? {});
    Object.assign(platters.B, s.platters?.B ?? {});
    workshop = validWorkshop(s.workshop);
    // Old state files predate winAt: treat as "won long ago" so the reset
    // cooldown is already expired rather than blocking forever.
    winAt = Number.isFinite(s.winAt) ? s.winAt : 0;
    console.log(`[relay] loaded state: ${edits.size} edits, ${repaired.size} repairs`);
  } catch (e) {
    console.error('[relay] state load failed, starting fresh:', e.message);
  }
}

function saveState() {
  if (!dirty) return;
  dirty = false;
  const tmp = STATE_FILE + '.tmp';
  writeFileSync(tmp, JSON.stringify({
    edits: [...edits.entries()], repaired: [...repaired], platters, workshop, winAt,
  }));
  renameSync(tmp, STATE_FILE);
}

// ---- helpers -----------------------------------------------------------
const isInt = (v) => Number.isInteger(v);
const inBounds = (x, y, z) =>
  isInt(x) && isInt(y) && isInt(z) &&
  x >= 0 && x < WORLD.x && y >= 0 && y < WORLD.y && z >= 0 && z < WORLD.z;
const finiteVec3 = (p) => Array.isArray(p) && p.length === 3 && p.every(Number.isFinite);
const cleanName = (n) =>
  (typeof n === 'string' ? n : '').replace(/[^\w \-.]/g, '').slice(0, MAX_NAME_LEN) || 'lil dj';

let nextId = 1;
const peers = new Map(); // id -> { ws, name, alive, msgTimes }

function send(ws, msg) {
  if (ws.readyState === ws.OPEN) ws.send(JSON.stringify(msg));
}
function broadcast(msg, exceptId = null) {
  const raw = JSON.stringify(msg);
  for (const [id, p] of peers) {
    if (id !== exceptId && p.ws.readyState === p.ws.OPEN) p.ws.send(raw);
  }
}

// ---- server ------------------------------------------------------------
loadState();
const wss = new WebSocketServer({
  host: HOST, port: PORT, maxPayload: MAX_FRAME_BYTES, clientTracking: false,
  verifyClient: ({ origin }) => !origin || ALLOWED_ORIGINS.some((re) => re.test(origin)),
});

wss.on('connection', (ws) => {
  if (peers.size >= MAX_PEERS) {
    send(ws, { t: 'full' });
    ws.close(1013, 'room full');
    return;
  }
  const id = nextId++;
  const peer = {
    ws, name: 'lil dj', alive: true, budget: MAX_MSGS_PER_SEC,
    avatar: validAvatar(null), lastEmote: 0, lastAvatar: 0,
  };
  peers.set(id, peer);

  send(ws, {
    t: 'hello', id,
    peers: [...peers.entries()].filter(([pid]) => pid !== id)
      .map(([pid, p]) => ({ id: pid, name: p.name, avatar: p.avatar })),
    state: { edits: [...edits.entries()], repaired: [...repaired], platters, workshop },
  });

  ws.on('pong', () => { peer.alive = true; });

  ws.on('message', (data, isBinary) => {
    if (isBinary || data.length > MAX_FRAME_BYTES) return;
    if (--peer.budget < 0) return; // over rate: drop silently (budget refills each second)
    let m;
    try { m = JSON.parse(data.toString()); } catch { return; }
    if (!m || typeof m.t !== 'string') return;

    switch (m.t) {
      case 'hi': {
        peer.name = cleanName(m.name);
        peer.avatar = validAvatar(m.avatar); // absent/garbage -> defaults
        broadcast({ t: 'join', id, name: peer.name, avatar: peer.avatar }, id);
        break;
      }
      case 'avatar': {
        const now = Date.now();
        if (now - peer.lastAvatar < AVATAR_COOLDOWN_MS) return; // drop, don't queue
        peer.lastAvatar = now;
        peer.avatar = validAvatar(m.avatar);
        broadcast({ t: 'avatar', id, avatar: peer.avatar }, id);
        break;
      }
      case 'emote': {
        if (!isInt(m.kind) || m.kind < 0 || m.kind >= EMOTE_KINDS) return;
        const now = Date.now();
        if (now - peer.lastEmote < EMOTE_COOLDOWN_MS) return; // spam ceiling
        peer.lastEmote = now;
        broadcast({ t: 'emote', id, kind: m.kind }, id);
        break;
      }
      case 'reset': {
        // Server-authoritative. Only a won booth resets, and only after the
        // anti-grief cooldown. Rejections are silent-ish: the client shows
        // "the fuse is still hot" off its own read of the state.
        if (repaired.size < NODES.size) return;
        if (Date.now() - winAt < RESET_COOLDOWN_MS) return;
        repaired.clear();
        platters.A = { playing: false, rpm: 33 };
        platters.B = { playing: false, rpm: 33 };
        workshop = resetWorkshopPose();
        winAt = 0;
        dirty = true;
        // NOTE: `edits` is deliberately untouched — player builds survive.
        // Carry the workshop pose so live clients land on the same state a late
        // joiner would get from `hello.state.workshop`.
        broadcast({ t: 'reset', by: peer.name, workshop }); // everyone incl. the breaker
        saveState();
        break;
      }
      case 'pos': {
        if (!finiteVec3(m.p) || !finiteVec3(m.look)) return;
        broadcast({ t: 'pos', id, p: m.p, look: m.look }, id);
        break;
      }
      case 'edit': {
        if (!inBounds(m.x, m.y, m.z)) return;
        if (!isInt(m.id) || m.id < 0 || m.id > MAX_BLOCK_ID) return;
        const key = `${m.x},${m.y},${m.z}`;
        if (!edits.has(key) && edits.size >= MAX_EDITS) return;
        edits.set(key, m.id);
        dirty = true;
        broadcast({ t: 'edit', x: m.x, y: m.y, z: m.z, id: m.id }, id);
        break;
      }
      case 'repair': {
        if (!NODES.has(m.node) || repaired.has(m.node)) return;
        repaired.add(m.node);
        // The moment the booth comes alive, start the reset cooldown clock.
        if (repaired.size === NODES.size) winAt = Date.now();
        dirty = true;
        broadcast({ t: 'repair', node: m.node }, id);
        break;
      }
      case 'platter': {
        if (m.deck !== 'A' && m.deck !== 'B') return;
        if (typeof m.playing !== 'boolean' || (m.rpm !== 33 && m.rpm !== 45)) return;
        platters[m.deck] = { playing: m.playing, rpm: m.rpm };
        dirty = true;
        broadcast({ t: 'platter', deck: m.deck, playing: m.playing, rpm: m.rpm }, id);
        break;
      }
      case 'workshop': {
        const s = validWorkshop(m.s);
        if (!s) return; // fuzz: bad shapes dropped
        workshop = s;
        dirty = true;
        broadcast({ t: 'workshop', s }, id);
        break;
      }
      default: // unknown type: ignore
    }
  });

  ws.on('close', () => {
    peers.delete(id);
    broadcast({ t: 'leave', id });
  });
  ws.on('error', () => { /* close follows */ });
});

setInterval(() => {
  for (const p of peers.values()) p.budget = MAX_MSGS_PER_SEC;
}, 1000);

setInterval(() => {
  for (const [id, p] of peers) {
    if (!p.alive) { p.ws.terminate(); peers.delete(id); broadcast({ t: 'leave', id }); continue; }
    p.alive = false;
    p.ws.ping();
  }
}, 30_000);

setInterval(saveState, 30_000);
for (const sig of ['SIGINT', 'SIGTERM']) {
  process.on(sig, () => { saveState(); process.exit(0); });
}

console.log(`[relay] turncraft relay on ws://${HOST}:${PORT} (room cap ${MAX_PEERS})`);