// LANE M — SIDE B shared helpers for the crate-world machines.
// Positions come from the contract (src/core/worlds.ts); this file only adds
// the small conversions every world machine needs. No game state lives here.

import { WORLD_DEFS, WORLD_KEYS, type WorldKey } from '../../core/worlds';
import { bus, type GameEvents } from '../../core/events';
import type { IPlayerView, Vec3 } from '../../core/types';

/** Walkable floor level inside every pocket: shell 142 + dressing 143 → feet 144. */
export const POCKET_WALK_Y = 144;

/** Out-of-pocket safety altitude (brief M1): above this and outside any pocket
 *  bounds, the player is teleported home. The booth wall top is 140. */
export const POCKET_SAFETY_Y = 141;

/**
 * Emit `machine:interact`, optionally carrying the SIDEB briefs' `index` field
 * (disco cues, acid locks). The contract payload is `{machineId, action}`;
 * `index` rides along as a structural extra so Lanes S/E2 — whose briefs quote
 * `{action:'disco_cue', index}` — can read it, while the contract file stays
 * untouched. The tile/pedestal id is ALSO encoded in machineId
 * (`disco_tile_<i>`, `acid_ped<i>`) so consumers can use either.
 */
export function interactAt(machineId: string, action: string, index?: number): void {
  const payload: GameEvents['machine:interact'] & { index?: number } = { machineId, action };
  if (index !== undefined) payload.index = index;
  bus.emit('machine:interact', payload);
}

/** Is a world-space point inside a pocket's INCLUSIVE voxel bounds (+margin)? */
export function insidePocket(k: WorldKey, x: number, y: number, z: number, margin = 0.5): boolean {
  const d = WORLD_DEFS[k];
  return (
    x >= d.pocketMin[0] - margin && x <= d.pocketMax[0] + 1 + margin &&
    y >= d.pocketMin[1] - margin && y <= d.pocketMax[1] + 1 + margin &&
    z >= d.pocketMin[2] - margin && z <= d.pocketMax[2] + 1 + margin
  );
}

/** The pocket the point is inside, or null. */
export function pocketAt(x: number, y: number, z: number): WorldKey | null {
  for (const k of WORLD_KEYS) if (insidePocket(k, x, y, z)) return k;
  return null;
}

/** Nearest world by xz distance to the pocket centre (safety-net homing). */
export function nearestWorld(x: number, z: number): WorldKey {
  let best: WorldKey = WORLD_KEYS[0];
  let bestD = Infinity;
  for (const k of WORLD_KEYS) {
    const d = WORLD_DEFS[k];
    const cx = (d.pocketMin[0] + d.pocketMax[0]) / 2;
    const cz = (d.pocketMin[2] + d.pocketMax[2]) / 2;
    const dd = (x - cx) * (x - cx) + (z - cz) * (z - cz);
    if (dd < bestD) { bestD = dd; best = k; }
  }
  return best;
}

/**
 * Lane B's PlayerController exposes `teleport` and `isFlying` beyond the
 * IPlayerView contract. We reach them structurally (optional), never by
 * importing Lane B — a mock player without them simply doesn't move.
 */
export interface PlayerControl {
  teleport?(v: Vec3): void;
  isFlying?: boolean;
}

export function teleportPlayer(p: IPlayerView | null, v: Vec3): void {
  (p as (IPlayerView & PlayerControl) | null)?.teleport?.(v);
}

export function playerFlying(p: IPlayerView | null): boolean {
  return (p as (IPlayerView & PlayerControl) | null)?.isFlying === true;
}

/** Tiny deterministic PRNG (mulberry32) for per-entry quest seeds. */
export function mulberry32(seed: number): () => number {
  let a = seed >>> 0;
  return () => {
    a = (a + 0x6d2b79f5) >>> 0;
    let t = a;
    t = Math.imul(t ^ (t >>> 15), t | 1);
    t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
  };
}

/** A fresh per-entry seed (wall clock + a counter so re-entries differ). */
let seedCounter = 0;
export function entrySeed(): number {
  seedCounter = (seedCounter + 0x9e3779b9) >>> 0;
  return (Date.now() ^ seedCounter) >>> 0;
}