import {
  AffineTransform,
  getRegionDelta,
  Point,
  Rect,
  Region,
  Size,
  unionRects,
} from "@noya-app/noya-geometry";
import {
  getBestSnapDelta,
  getElementSnapDelta,
  getGridSnapDelta,
  getValuesOnAxis,
} from "./snapUtils";

export type MovingOptions = {
  constrainToSingleAxis?: boolean;
  ignoreSnapping?: boolean;
};

export function getMovingOptionsForEvent({
  shiftKey,
  ctrlKey,
}: {
  shiftKey: boolean;
  ctrlKey: boolean;
}): MovingOptions {
  return {
    constrainToSingleAxis: shiftKey,
    ignoreSnapping: ctrlKey,
  };
}

export function getMoveTransform(
  delta: Point | Region,
  { constrainToSingleAxis }: MovingOptions
) {
  if ("anchor" in delta) {
    delta = getRegionDelta(delta);
  }

  if (constrainToSingleAxis) {
    if (Math.abs(delta.x) > Math.abs(delta.y)) {
      return AffineTransform.translate(delta.x, 0);
    } else {
      return AffineTransform.translate(0, delta.y);
    }
  } else {
    return AffineTransform.translate(delta);
  }
}

export function getMoveSnapDelta({
  movingRects,
  stationaryRects,
  delta,
  gridSize,
  options,
}: {
  movingRects: Rect[];
  stationaryRects: Rect[];
  delta: Point;
  gridSize: Size;
  options: MovingOptions;
}) {
  const movingBoundingBox = unionRects(...movingRects);

  const transform = getMoveTransform(delta, options);
  const transformedMovingRect = transform.applyTo(movingBoundingBox);

  const possibleSnapsX = [
    getElementSnapDelta({
      movingValues: getValuesOnAxis(transformedMovingRect, "x"),
      stationaryValues: getValuesOnAxis(stationaryRects, "x"),
    }),
    getGridSnapDelta({
      value: transformedMovingRect.x,
      gridSize: gridSize.width,
    }),
  ];

  const possibleSnapsY = [
    getElementSnapDelta({
      movingValues: getValuesOnAxis(transformedMovingRect, "y"),
      stationaryValues: getValuesOnAxis(stationaryRects, "y"),
    }),
    getGridSnapDelta({
      value: transformedMovingRect.y,
      gridSize: gridSize.height,
    }),
  ];

  const snapDelta = {
    x: getBestSnapDelta(possibleSnapsX),
    y: getBestSnapDelta(possibleSnapsY),
  };

  return {
    x: delta.x + snapDelta.x,
    y: delta.y + snapDelta.y,
  };
}