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

import { Facing, ShortLinesPosition, PositionKind, CirclePosition, SemanticPosition, HandConnection, HandTo, oppositeFacing } from "../interpreterCommon.js";
import { Move } from "../libfigureMapper.js";
import { SemanticAnimationKind } from "../lowLevelMove.js";
import { Hand } from "../rendererConstants.js";
import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";

const moveName: Move["move"] = "down the hall";

class DownTheHallSingleVariant extends SingleVariantMoveInterpreter<DownTheHall, typeof moveName> {
  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
    if (this.move.parameters.who !== "everyone") {
      throw new Error("Don't know what it means for not everyone to go down the hall.");
    }
    if (this.move.parameters.moving !== "all") {
      throw new Error("Not sure what it means for not all to be moving in down the hall.");
    }
    if (this.move.parameters.ender !== "turn-alone" && this.move.parameters.ender !== "turn-couple") {
      throw new Error("Unsupported down the hall ender: " + this.move.parameters.ender);
    }
    if (this.move.parameters.facing === "forward then backward") {
      throw new Error("Not sure what " + this.move.parameters.facing + " means for down the hall.");
    }
    return this.handleMove(({ startPos }) => {
      const startFacing = this.move.parameters.facing === "backward" ? Facing.Up : Facing.Down;
      if (startPos.facing !== startFacing && (startPos.facing === Facing.Up || startPos.facing === Facing.Down)) {
        throw new Error("Started facing the wrong direction.");
      }
      const startWhich: ShortLinesPosition = startPos.kind === PositionKind.ShortLines
        ? startPos.which
        // TODO Is this always the right way to convert circle to short lines?
        //      (Does it even matter except for dance starting formations?)
        : new Map<CirclePosition, ShortLinesPosition>([
          [CirclePosition.TopLeft, ShortLinesPosition.FarLeft],
          [CirclePosition.BottomLeft, ShortLinesPosition.MiddleLeft],
          [CirclePosition.BottomRight, ShortLinesPosition.MiddleRight],
          [CirclePosition.TopRight, ShortLinesPosition.FarRight],
        ]).get(startPos.which)!;
      const startingPos: SemanticPosition & { kind: PositionKind.ShortLines, setOffset: number } = {
        kind: PositionKind.ShortLines,
        facing: startFacing,
        which: startWhich,
        hands: startWhich.isMiddle() ? new Map<Hand, HandConnection>([
          [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }],
          [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }],
        ]) : new Map<Hand, HandConnection>([
          startWhich.isLeft() === (this.move.parameters.facing === "backward")
            ? [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }]
            : [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }]
        ]),
        setOffset: startPos.setOffset ?? 0,
        lineOffset: startPos.lineOffset,
      };

      return this.combine([
        {
          beats: 4,
          endPosition: {
            ...startingPos,
            setOffset: startingPos.setOffset + 1
          },
          movementPattern: { kind: SemanticAnimationKind.Linear },
        },
        {
          beats: this.move.beats - 4,
          endPosition: {
            ...startingPos,
            setOffset: startingPos.setOffset + 1,
            facing: oppositeFacing(startFacing),
            which: this.move.parameters.ender === "turn-alone" ? startWhich : startWhich.swapOnSide(),
          },
          movementPattern: this.move.parameters.ender === "turn-couple"
            ? {
              kind: SemanticAnimationKind.TwirlSwap,
              around: startWhich.leftRightSide(),
              // !== is NXOR, each of these booleans being flipped flips which hand to use.
              hand: startWhich.isMiddle() !== (startWhich.isLeft() !== (this.move.parameters.facing === "forward"))
                ? Hand.Left
                : Hand.Right
            }
            : {
              kind: SemanticAnimationKind.Linear,
              minRotation: startWhich.isMiddle() === startWhich.isLeft() ? -180 : +180,
            },
        },
      ], startingPos);
    });
  }
}

class DownTheHall extends MoveInterpreter<typeof moveName> {
  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
    return new DownTheHallSingleVariant(this, startingPos);
  }
}

moveInterpreters.set(moveName, DownTheHall);