contra-renderer/www/js/moves/boxTheGnat.ts

import { HandConnection, HandTo, BalanceWeight, facingRequireAdjacent } from "../interpreterCommon.js";
import { SemanticAnimationKind } from "../lowLevelMove.js";
import { Hand } from "../rendererConstants.js";
import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, MoveInterpreterCtorArgs, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";

const moveName = "box the gnat";

class BoxTheGnatSingleVariant extends SingleVariantMoveInterpreter<BoxTheGnat, typeof moveName> {
  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
    return this.handlePairedMove(this.move.parameters.who, ({ startPos, around, withPos }) => {
      if (startPos.hands && startPos.hands.get(Hand.Right) === undefined && startPos.hands.get(Hand.Left)?.hand === Hand.Left) {
        throw new Error(this.move.move + " shouldn't start with holding left hands. Something went wrong.");
      }
      if (startPos.balance && startPos.balance !== BalanceWeight.Backward) {
        throw new Error(this.move.move + " shouldn't start with balance weight " + startPos.balance);
      }

      const facing = facingRequireAdjacent(startPos, withPos, this.move.move);
      const startPosition = { ...startPos, hands: this.moveInterpreter.hands, facing };

      if (around === "Center") {
        throw "TwirlSwap around center is unsupported.";
      }

      const twirl: PartialLowLevelMove = {
        beats: this.moveInterpreter.twirlBeats,
        endPosition: { ...withPos, balance: undefined },
        movementPattern: {
          kind: SemanticAnimationKind.TwirlSwap,
          around,
          hand: this.moveInterpreter.hand,
        }
      };

      if (this.move.parameters.bal) {
        return this.combine([
          {
            beats: this.moveInterpreter.balancePartBeats,
            endPosition: {
              ...startPosition,
              balance: BalanceWeight.Forward,
            },
            movementPattern: {
              kind: SemanticAnimationKind.Linear,
            }
          },
          {
            beats: this.moveInterpreter.balancePartBeats,
            endPosition: {
              ...startPosition,
              balance: BalanceWeight.Backward,
            },
            movementPattern: {
              kind: SemanticAnimationKind.Linear,
            }
          },
          twirl], startPosition);
      } else {
        return this.combine([twirl], startPosition);
      }
    });
  }
}

class BoxTheGnat extends MoveInterpreter<typeof moveName> {
  public readonly hand: Hand;
  public readonly hands: Map<Hand, HandConnection>;
  public readonly balancePartBeats: number;
  public readonly twirlBeats: number;

  constructor(args: MoveInterpreterCtorArgs<typeof moveName>) {
    super(args);

    this.hand = this.move.parameters.hand ? Hand.Right : Hand.Left;
    this.hands = new Map<Hand, HandConnection>([[this.hand, { hand: this.hand, to: HandTo.DancerForward }]]);
    const balanceBeats = this.move.parameters.bal
      ? this.move.beats > 4
        ? this.move.beats - 4
        : this.move.beats / 2
      : 0;
    this.balancePartBeats = balanceBeats / 2;
    this.twirlBeats = this.move.beats - balanceBeats;
  }

  override allowStartingBalance(): boolean {
    return true;
  }

  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
    return new BoxTheGnatSingleVariant(this, startingPos);
  }
}

moveInterpreters.set(moveName, BoxTheGnat);