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

import { CoupleRole, DanceRole } from "../danceCommon.js";
import { LongLines, CircleSide, SemanticPosition, CirclePosition, Facing, PositionKind, HandConnection, HandTo, ShortLinesPosition, handsInLine, BalanceWeight, DancerDistance } from "../interpreterCommon.js";
import { Move } from "../libfigureMapper.js";
import { SemanticAnimationKind } from "../lowLevelMove.js";
import { Hand } from "../rendererConstants.js";
import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";

const moveName: Move["move"] = "swing";

class SwingSingleVariant extends SingleVariantMoveInterpreter<Swing, typeof moveName> {
  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
    // TODO Use variants instead of nextMove
    const nextMove = this.moveInterpreter.nextMove;

    return this.handlePairedMove(this.move.parameters.who, ({ id, startPos, around, withId, withPos }) => {
      // TODO swing can start from non-circle positions.
      // TODO swing end is only in notes / looking at next move.

      // TODO better way to detect swing end?
      // TODO more structured way to do this than enumerating next moves here?
      //      maybe instead of nextMove an optional endPosition for fixing up positions?
      //      ... but then every move would have to handle that...
      const afterTake = startPos.longLines === LongLines.Near || withPos.longLines === LongLines.Near;
      const toShortLines = nextMove.move === "down the hall" || nextMove.move === "up the hall";
      const endFacingAcross = (around === CircleSide.Left || around === CircleSide.Right) && !toShortLines;

      const startWhich = startPos.which;
      const startPosition: SemanticPosition = {
        ...startPos,
        facing: around === CircleSide.Left || CircleSide.Right
          ? (startWhich instanceof CirclePosition
            ? afterTake
              ? startPos.longLines === LongLines.Near ? startWhich.facingOut() : startWhich.facingAcross()
              : (startWhich.topBottomSide() === CircleSide.Bottom ? Facing.Up : Facing.Down)
            : startWhich.facingSide())
          : (startWhich.isLeft() ? Facing.Right : Facing.Left),
      };

      const swingRole = id.danceRole != withId.setIdentity.danceRole
        ? id.danceRole
        // Make some arbitrary choice for same-role swings
        : id.coupleRole !== withId.setIdentity.coupleRole
          ? (id.coupleRole === CoupleRole.Ones ? DanceRole.Lark : DanceRole.Robin)
          : withId.relativeSet !== 0
            ? (withId.relativeSet > 0 ? DanceRole.Lark : DanceRole.Robin)
            : withId.relativeLine !== 0
              ? (withId.relativeLine > 0 ? DanceRole.Lark : DanceRole.Robin)
              : /* should be unreachable as this means withId is equal to id */ DanceRole.Lark;

      // TODO This assumes swing around right/left, not center or top/bottom.
      let endPosition: SemanticPosition;
      if (endFacingAcross) {
        endPosition = {
          ...startPos,
          kind: PositionKind.Circle,
          which: startWhich instanceof CirclePosition
            ? (startWhich.isOnLeftLookingAcross() === (swingRole === DanceRole.Lark)
              ? startWhich
              : startWhich.swapUpAndDown())
            : (startWhich.isLeft()
              ? (swingRole === DanceRole.Lark ? CirclePosition.BottomLeft : CirclePosition.TopLeft)
              : (swingRole === DanceRole.Lark ? CirclePosition.TopRight : CirclePosition.BottomRight)),
          facing: startWhich.leftRightSide() === CircleSide.Left ? Facing.Right : Facing.Left,
          balance: undefined,
          dancerDistance: undefined,
          longLines: undefined,
          hands: new Map<Hand, HandConnection>([swingRole === DanceRole.Lark
            ? [Hand.Right, { to: HandTo.DancerRight, hand: Hand.Left }]
            : [Hand.Left, { to: HandTo.DancerLeft, hand: Hand.Right }]]),
        };
      } else if (toShortLines) {
        const endFacing = nextMove.move === "down the hall" !== (nextMove.parameters.facing === "backward")
          ? Facing.Down
          : Facing.Up;
        const endWhich = startWhich.isLeft()
          ? ((endFacing === Facing.Down) === (swingRole === DanceRole.Lark) ? ShortLinesPosition.FarLeft : ShortLinesPosition.MiddleLeft)
          : ((endFacing === Facing.Down) === (swingRole === DanceRole.Lark) ? ShortLinesPosition.MiddleRight : ShortLinesPosition.FarRight)
        endPosition = {
          ...startPos,
          kind: PositionKind.ShortLines,
          which: endWhich,
          facing: endFacing,
          balance: undefined,
          dancerDistance: undefined,
          longLines: undefined,
          hands: handsInLine({ wavy: false, which: endWhich, facing: endFacing }),
        };
      }
      else {
        // TODO Need to figure out the logic of knowing if this should be facing up or down.
        //  Probably based on knowing Ones vs. Twos? Also then the not-participating-dancers need their
        //  "standing still" to update that they are in a new set...
        //throw new Error("Swing to new circle currently unsupported.");
        endPosition = {
          // end not facing across or in short lines, so transitioning to new circle like in many contra corners dances.
          ...startPos,
        };
      }

      const swingBeats = this.move.parameters.prefix === "none" ? this.move.beats
        : this.move.parameters.prefix === "balance"
          ? this.move.beats > 8 ? 8 : this.move.beats - 4
          : this.move.parameters.prefix === "meltdown"
            ? this.move.beats - 4
            : (() => { throw "Unknown swing prefix: " + this.move.parameters.prefix })();

      const swing: PartialLowLevelMove = {
        beats: swingBeats,
        endPosition: endPosition,
        movementPattern: {
          kind: SemanticAnimationKind.Swing,
          minAmount: 360,
          around,
          endFacing: startWhich.leftRightSide() === CircleSide.Left ? Facing.Right : Facing.Left,
          swingRole,
          afterTake,
        },
      };

      switch (this.move.parameters.prefix) {
        case "none":
          return this.combine([swing,], startPosition);
        case "balance":
          // TODO Right length for balance?
          const balancePartBeats = this.move.beats > 8 ? (this.move.beats - 8) / 2 : 2;
          const startWithBalHands = {
            ...startPosition,
            hands: new Map<Hand, HandConnection>([
              [Hand.Left, { to: HandTo.DancerForward, hand: Hand.Right }],
              [Hand.Right, { to: HandTo.DancerForward, hand: Hand.Left }],
            ]),
          };
          const balForwardPos = startWithBalHands.kind === PositionKind.Circle
            ? {
              ...startWithBalHands,
              balance: BalanceWeight.Forward,
              dancerDistance: DancerDistance.Compact,
            }
            : {
              ...startWithBalHands,
              balance: BalanceWeight.Forward,
            };
          return this.combine([
            {
              beats: balancePartBeats,
              startPosition: startWithBalHands,
              endPosition: balForwardPos,
              movementPattern: { kind: SemanticAnimationKind.Linear, },
            },
            prevEnd => ({
              beats: balancePartBeats,
              endPosition: {
                ...prevEnd,
                balance: BalanceWeight.Backward,
              },
              movementPattern: { kind: SemanticAnimationKind.Linear, },
            }),
            swing,
          ], startPosition);
        case "meltdown":
          const meltdownBeats = 4; // TODO right number here?
          return this.combine([
            prevEnd => ({
              beats: meltdownBeats,
              endPosition: { ...prevEnd, dancerDistance: DancerDistance.Compact },
              movementPattern: {
                kind: SemanticAnimationKind.RotateAround,
                minAmount: 360,
                around,
                byHand: undefined,
                close: true,
              },
            }),
            swing,
          ], startPosition);
      }
    });
  }
}

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

moveInterpreters.set(moveName, Swing);