import React, { useEffect, useId, useRef, useState } from 'react';

import DiceBox from '@3d-dice/dice-box-threejs';

import {
  formatPredeterminedDiceNotation,
  isDiceSides,
  type DiceRollState,
} from '../../../shared/types/diceRoll';

import { useDiceRollState } from './useDiceRollState';
import styles from './DiceRollLayer.module.css';

function diceAssetPath(): string {
  const base = import.meta.env.BASE_URL || '/';
  const joined = `${base}dice-box/`.replace(/([^:]\/)\/+/g, '$1');
  return joined;
}

function parseNotationSides(notation: string): number | null {
  const m = /^(\d+)d(\d+)$/i.exec(notation.trim());
  if (!m) return null;
  const sides = Number(m[2]);
  return Number.isFinite(sides) ? sides : null;
}

function parseNotationCount(notation: string): number {
  const m = /^(\d+)d(\d+)$/i.exec(notation.trim());
  if (!m) return 1;
  return Math.max(1, Number(m[1]) || 1);
}

/** Полноэкранный оверлей 3D-броска на превью и презентации. */
export function DiceRollLayer() {
  const [state] = useDiceRollState();
  const reactId = useId().replace(/:/g, '');
  const hostId = `dice-roll-host-${reactId}`;
  const boxRef = useRef<DiceBox | null>(null);
  const rollingRef = useRef(false);
  const lastRevisionRef = useRef(0);
  const [ready, setReady] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    let cancelled = false;
    const box = new DiceBox(`#${hostId}`, {
      assetPath: diceAssetPath(),
      sounds: false,
      shadows: true,
      theme_surface: 'green-felt',
      theme_colorset: 'white',
      theme_material: 'glass',
      strength: 1,
      gravity_multiplier: 400,
    });
    boxRef.current = box;
    void box
      .initialize()
      .then(() => {
        if (!cancelled) setReady(true);
      })
      .catch((err: unknown) => {
        if (cancelled) return;
        setError(err instanceof Error ? err.message : String(err));
      });
    return () => {
      cancelled = true;
      try {
        box.clearDice?.();
      } catch {
        /* ignore */
      }
      boxRef.current = null;
      const el = document.getElementById(hostId);
      el?.replaceChildren();
    };
  }, [hostId]);

  useEffect(() => {
    if (!ready || !state?.active) return;
    if (state.revision === lastRevisionRef.current) return;
    if (rollingRef.current) return;
    const box = boxRef.current;
    if (!box) return;

    const sidesRaw = parseNotationSides(state.notation);
    if (sidesRaw == null || !isDiceSides(sidesRaw)) return;
    const count = parseNotationCount(state.notation);
    const notation = formatPredeterminedDiceNotation(count, sidesRaw, state.values);
    const revision = state.revision;
    lastRevisionRef.current = revision;
    rollingRef.current = true;

    void (async () => {
      try {
        await box.roll(notation);
      } catch (err) {
        console.error('[dice] roll failed', err);
      } finally {
        rollingRef.current = false;
      }
    })();
  }, [ready, state]);

  const visible = Boolean(state?.active);
  return (
    <div
      className={styles.layer}
      data-testid="dice-roll-layer"
      data-active={visible ? '1' : '0'}
      aria-hidden={visible ? undefined : true}
    >
      <div className={styles.backdrop} />
      <div className={styles.tray}>
        <div id={hostId} className={styles.host} />
        {error ? <div className={styles.error}>{error}</div> : null}
        {visible && state ? <DiceResultBadge state={state} /> : null}
      </div>
    </div>
  );
}

function DiceResultBadge({ state }: { state: DiceRollState }) {
  if (!state.values.length) return null;
  return (
    <div className={styles.result} data-testid="dice-roll-result">
      <span className={styles.resultNotation}>{state.notation}</span>
      <span className={styles.resultValues}>{state.values.join(' + ')}</span>
      <span className={styles.resultTotal}>= {state.total}</span>
    </div>
  );
}