import React, { useMemo, useRef, useEffect, useState, useContext } from 'react';
import { useDndContext, getClientRect, useDroppable, useDraggable, closestCorners, getFirstCollision, getScrollableAncestors, KeyboardCode } from '@dnd-kit/core';
import { useUniqueId, useIsomorphicLayoutEffect, CSS, useCombinedRefs, isKeyboardEvent, subtract } from '@dnd-kit/utilities';

/**
 * Move an array item to a different position. Returns a new array with the item moved to the new position.
 */
function arrayMove(array, from, to) {
  const newArray = array.slice();
  newArray.splice(to < 0 ? newArray.length + to : to, 0, newArray.splice(from, 1)[0]);
  return newArray;
}

/**
 * Swap an array item to a different position. Returns a new array with the item swapped to the new position.
 */
function arraySwap(array, from, to) {
  const newArray = array.slice();
  newArray[from] = array[to];
  newArray[to] = array[from];
  return newArray;
}

function getSortedRects(items, rects) {
  return items.reduce((accumulator, id, index) => {
    const rect = rects.get(id);

    if (rect) {
      accumulator[index] = rect;
    }

    return accumulator;
  }, Array(items.length));
}

function isValidIndex(index) {
  return index !== null && index >= 0;
}

function itemsEqual(a, b) {
  if (a === b) {
    return true;
  }

  if (a.length !== b.length) {
    return false;
  }

  for (let i = 0; i < a.length; i++) {
    if (a[i] !== b[i]) {
      return false;
    }
  }

  return true;
}

function normalizeDisabled(disabled) {
  if (typeof disabled === 'boolean') {
    return {
      draggable: disabled,
      droppable: disabled
    };
  }

  return disabled;
}

// To-do: We should be calculating scale transformation
const defaultScale = {
  scaleX: 1,
  scaleY: 1
};
const horizontalListSortingStrategy = _ref => {
  var _rects$activeIndex;

  let {
    rects,
    activeNodeRect: fallbackActiveRect,
    activeIndex,
    overIndex,
    index
  } = _ref;
  const activeNodeRect = (_rects$activeIndex = rects[activeIndex]) != null ? _rects$activeIndex : fallbackActiveRect;

  if (!activeNodeRect) {
    return null;
  }

  const itemGap = getItemGap(rects, index, activeIndex);

  if (index === activeIndex) {
    const newIndexRect = rects[overIndex];

    if (!newIndexRect) {
      return null;
    }

    return {
      x: activeIndex < overIndex ? newIndexRect.left + newIndexRect.width - (activeNodeRect.left + activeNodeRect.width) : newIndexRect.left - activeNodeRect.left,
      y: 0,
      ...defaultScale
    };
  }

  if (index > activeIndex && index <= overIndex) {
    return {
      x: -activeNodeRect.width - itemGap,
      y: 0,
      ...defaultScale
    };
  }

  if (index < activeIndex && index >= overIndex) {
    return {
      x: activeNodeRect.width + itemGap,
      y: 0,
      ...defaultScale
    };
  }

  return {
    x: 0,
    y: 0,
    ...defaultScale
  };
};

function getItemGap(rects, index, activeIndex) {
  const currentRect = rects[index];
  const previousRect = rects[index - 1];
  const nextRect = rects[index + 1];

  if (!currentRect || !previousRect && !nextRect) {
    return 0;
  }

  if (activeIndex < index) {
    return previousRect ? currentRect.left - (previousRect.left + previousRect.width) : nextRect.left - (currentRect.left + currentRect.width);
  }

  return nextRect ? nextRect.left - (currentRect.left + currentRect.width) : currentRect.left - (previousRect.left + previousRect.width);
}

const rectSortingStrategy = _ref => {
  let {
    rects,
    activeIndex,
    overIndex,
    index
  } = _ref;
  const newRects = arrayMove(rects, overIndex, activeIndex);
  const oldRect = rects[index];
  const newRect = newRects[index];

  if (!newRect || !oldRect) {
    return null;
  }

  return {
    x: newRect.left - oldRect.left,
    y: newRect.top - oldRect.top,
    scaleX: newRect.width / oldRect.width,
    scaleY: newRect.height / oldRect.height
  };
};

const rectSwappingStrategy = _ref => {
  let {
    activeIndex,
    index,
    rects,
    overIndex
  } = _ref;
  let oldRect;
  let newRect;

  if (index === activeIndex) {
    oldRect = rects[index];
    newRect = rects[overIndex];
  }

  if (index === overIndex) {
    oldRect = rects[index];
    newRect = rects[activeIndex];
  }

  if (!newRect || !oldRect) {
    return null;
  }

  return {
    x: newRect.left - oldRect.left,
    y: newRect.top - oldRect.top,
    scaleX: newRect.width / oldRect.width,
    scaleY: newRect.height / oldRect.height
  };
};

// To-do: We should be calculating scale transformation
const defaultScale$1 = {
  scaleX: 1,
  scaleY: 1
};
const verticalListSortingStrategy = _ref => {
  var _rects$activeIndex;

  let {
    activeIndex,
    activeNodeRect: fallbackActiveRect,
    index,
    rects,
    overIndex
  } = _ref;
  const activeNodeRect = (_rects$activeIndex = rects[activeIndex]) != null ? _rects$activeIndex : fallbackActiveRect;

  if (!activeNodeRect) {
    return null;
  }

  if (index === activeIndex) {
    const overIndexRect = rects[overIndex];

    if (!overIndexRect) {
      return null;
    }

    return {
      x: 0,
      y: activeIndex < overIndex ? overIndexRect.top + overIndexRect.height - (activeNodeRect.top + activeNodeRect.height) : overIndexRect.top - activeNodeRect.top,
      ...defaultScale$1
    };
  }

  const itemGap = getItemGap$1(rects, index, activeIndex);

  if (index > activeIndex && index <= overIndex) {
    return {
      x: 0,
      y: -activeNodeRect.height - itemGap,
      ...defaultScale$1
    };
  }

  if (index < activeIndex && index >= overIndex) {
    return {
      x: 0,
      y: activeNodeRect.height + itemGap,
      ...defaultScale$1
    };
  }

  return {
    x: 0,
    y: 0,
    ...defaultScale$1
  };
};

function getItemGap$1(clientRects, index, activeIndex) {
  const currentRect = clientRects[index];
  const previousRect = clientRects[index - 1];
  const nextRect = clientRects[index + 1];

  if (!currentRect) {
    return 0;
  }

  if (activeIndex < index) {
    return previousRect ? currentRect.top - (previousRect.top + previousRect.height) : nextRect ? nextRect.top - (currentRect.top + currentRect.height) : 0;
  }

  return nextRect ? nextRect.top - (currentRect.top + currentRect.height) : previousRect ? currentRect.top - (previousRect.top + previousRect.height) : 0;
}

const ID_PREFIX = 'Sortable';
const Context = /*#__PURE__*/React.createContext({
  activeIndex: -1,
  containerId: ID_PREFIX,
  disableTransforms: false,
  items: [],
  overIndex: -1,
  useDragOverlay: false,
  sortedRects: [],
  strategy: rectSortingStrategy,
  disabled: {
    draggable: false,
    droppable: false
  }
});
function SortableContext(_ref) {
  let {
    children,
    id,
    items: userDefinedItems,
    strategy = rectSortingStrategy,
    disabled: disabledProp = false
  } = _ref;
  const {
    active,
    dragOverlay,
    droppableRects,
    over,
    measureDroppableContainers
  } = useDndContext();
  const containerId = useUniqueId(ID_PREFIX, id);
  const useDragOverlay = Boolean(dragOverlay.rect !== null);
  const items = useMemo(() => userDefinedItems.map(item => typeof item === 'object' && 'id' in item ? item.id : item), [userDefinedItems]);
  const isDragging = active != null;
  const activeIndex = active ? items.indexOf(active.id) : -1;
  const overIndex = over ? items.indexOf(over.id) : -1;
  const previousItemsRef = useRef(items);
  const itemsHaveChanged = !itemsEqual(items, previousItemsRef.current);
  const disableTransforms = overIndex !== -1 && activeIndex === -1 || itemsHaveChanged;
  const disabled = normalizeDisabled(disabledProp);
  useIsomorphicLayoutEffect(() => {
    if (itemsHaveChanged && isDragging) {
      measureDroppableContainers(items);
    }
  }, [itemsHaveChanged, items, isDragging, measureDroppableContainers]);
  useEffect(() => {
    previousItemsRef.current = items;
  }, [items]);
  const contextValue = useMemo(() => ({
    activeIndex,
    containerId,
    disabled,
    disableTransforms,
    items,
    overIndex,
    useDragOverlay,
    sortedRects: getSortedRects(items, droppableRects),
    strategy
  }), // eslint-disable-next-line react-hooks/exhaustive-deps
  [activeIndex, containerId, disabled.draggable, disabled.droppable, disableTransforms, items, overIndex, droppableRects, useDragOverlay, strategy]);
  return React.createElement(Context.Provider, {
    value: contextValue
  }, children);
}

const defaultNewIndexGetter = _ref => {
  let {
    id,
    items,
    activeIndex,
    overIndex
  } = _ref;
  return arrayMove(items, activeIndex, overIndex).indexOf(id);
};
const defaultAnimateLayoutChanges = _ref2 => {
  let {
    containerId,
    isSorting,
    wasDragging,
    index,
    items,
    newIndex,
    previousItems,
    previousContainerId,
    transition
  } = _ref2;

  if (!transition || !wasDragging) {
    return false;
  }

  if (previousItems !== items && index === newIndex) {
    return false;
  }

  if (isSorting) {
    return true;
  }

  return newIndex !== index && containerId === previousContainerId;
};
const defaultTransition = {
  duration: 200,
  easing: 'ease'
};
const transitionProperty = 'transform';
const disabledTransition = /*#__PURE__*/CSS.Transition.toString({
  property: transitionProperty,
  duration: 0,
  easing: 'linear'
});
const defaultAttributes = {
  roleDescription: 'sortable'
};

/*
 * When the index of an item changes while sorting,
 * we need to temporarily disable the transforms
 */

function useDerivedTransform(_ref) {
  let {
    disabled,
    index,
    node,
    rect
  } = _ref;
  const [derivedTransform, setDerivedtransform] = useState(null);
  const previousIndex = useRef(index);
  useIsomorphicLayoutEffect(() => {
    if (!disabled && index !== previousIndex.current && node.current) {
      const initial = rect.current;

      if (initial) {
        const current = getClientRect(node.current, {
          ignoreTransform: true
        });
        const delta = {
          x: initial.left - current.left,
          y: initial.top - current.top,
          scaleX: initial.width / current.width,
          scaleY: initial.height / current.height
        };

        if (delta.x || delta.y) {
          setDerivedtransform(delta);
        }
      }
    }

    if (index !== previousIndex.current) {
      previousIndex.current = index;
    }
  }, [disabled, index, node, rect]);
  useEffect(() => {
    if (derivedTransform) {
      setDerivedtransform(null);
    }
  }, [derivedTransform]);
  return derivedTransform;
}

function useSortable(_ref) {
  let {
    animateLayoutChanges = defaultAnimateLayoutChanges,
    attributes: userDefinedAttributes,
    disabled: localDisabled,
    data: customData,
    getNewIndex = defaultNewIndexGetter,
    id,
    strategy: localStrategy,
    resizeObserverConfig,
    transition = defaultTransition
  } = _ref;
  const {
    items,
    containerId,
    activeIndex,
    disabled: globalDisabled,
    disableTransforms,
    sortedRects,
    overIndex,
    useDragOverlay,
    strategy: globalStrategy
  } = useContext(Context);
  const disabled = normalizeLocalDisabled(localDisabled, globalDisabled);
  const index = items.indexOf(id);
  const data = useMemo(() => ({
    sortable: {
      containerId,
      index,
      items
    },
    ...customData
  }), [containerId, customData, index, items]);
  const itemsAfterCurrentSortable = useMemo(() => items.slice(items.indexOf(id)), [items, id]);
  const {
    rect,
    node,
    isOver,
    setNodeRef: setDroppableNodeRef
  } = useDroppable({
    id,
    data,
    disabled: disabled.droppable,
    resizeObserverConfig: {
      updateMeasurementsFor: itemsAfterCurrentSortable,
      ...resizeObserverConfig
    }
  });
  const {
    active,
    activatorEvent,
    activeNodeRect,
    attributes,
    setNodeRef: setDraggableNodeRef,
    listeners,
    isDragging,
    over,
    setActivatorNodeRef,
    transform
  } = useDraggable({
    id,
    data,
    attributes: { ...defaultAttributes,
      ...userDefinedAttributes
    },
    disabled: disabled.draggable
  });
  const setNodeRef = useCombinedRefs(setDroppableNodeRef, setDraggableNodeRef);
  const isSorting = Boolean(active);
  const displaceItem = isSorting && !disableTransforms && isValidIndex(activeIndex) && isValidIndex(overIndex);
  const shouldDisplaceDragSource = !useDragOverlay && isDragging;
  const dragSourceDisplacement = shouldDisplaceDragSource && displaceItem ? transform : null;
  const strategy = localStrategy != null ? localStrategy : globalStrategy;
  const finalTransform = displaceItem ? dragSourceDisplacement != null ? dragSourceDisplacement : strategy({
    rects: sortedRects,
    activeNodeRect,
    activeIndex,
    overIndex,
    index
  }) : null;
  const newIndex = isValidIndex(activeIndex) && isValidIndex(overIndex) ? getNewIndex({
    id,
    items,
    activeIndex,
    overIndex
  }) : index;
  const activeId = active == null ? void 0 : active.id;
  const previous = useRef({
    activeId,
    items,
    newIndex,
    containerId
  });
  const itemsHaveChanged = items !== previous.current.items;
  const shouldAnimateLayoutChanges = animateLayoutChanges({
    active,
    containerId,
    isDragging,
    isSorting,
    id,
    index,
    items,
    newIndex: previous.current.newIndex,
    previousItems: previous.current.items,
    previousContainerId: previous.current.containerId,
    transition,
    wasDragging: previous.current.activeId != null
  });
  const derivedTransform = useDerivedTransform({
    disabled: !shouldAnimateLayoutChanges,
    index,
    node,
    rect
  });
  useEffect(() => {
    if (isSorting && previous.current.newIndex !== newIndex) {
      previous.current.newIndex = newIndex;
    }

    if (containerId !== previous.current.containerId) {
      previous.current.containerId = containerId;
    }

    if (items !== previous.current.items) {
      previous.current.items = items;
    }
  }, [isSorting, newIndex, containerId, items]);
  useEffect(() => {
    if (activeId === previous.current.activeId) {
      return;
    }

    if (activeId != null && previous.current.activeId == null) {
      previous.current.activeId = activeId;
      return;
    }

    const timeoutId = setTimeout(() => {
      previous.current.activeId = activeId;
    }, 50);
    return () => clearTimeout(timeoutId);
  }, [activeId]);
  return {
    active,
    activeIndex,
    attributes,
    data,
    rect,
    index,
    newIndex,
    items,
    isOver,
    isSorting,
    isDragging,
    listeners,
    node,
    overIndex,
    over,
    setNodeRef,
    setActivatorNodeRef,
    setDroppableNodeRef,
    setDraggableNodeRef,
    transform: derivedTransform != null ? derivedTransform : finalTransform,
    transition: getTransition()
  };

  function getTransition() {
    if ( // Temporarily disable transitions for a single frame to set up derived transforms
    derivedTransform || // Or to prevent items jumping to back to their "new" position when items change
    itemsHaveChanged && previous.current.newIndex === index) {
      return disabledTransition;
    }

    if (shouldDisplaceDragSource && !isKeyboardEvent(activatorEvent) || !transition) {
      return undefined;
    }

    if (isSorting || shouldAnimateLayoutChanges) {
      return CSS.Transition.toString({ ...transition,
        property: transitionProperty
      });
    }

    return undefined;
  }
}

function normalizeLocalDisabled(localDisabled, globalDisabled) {
  var _localDisabled$dragga, _localDisabled$droppa;

  if (typeof localDisabled === 'boolean') {
    return {
      draggable: localDisabled,
      // Backwards compatibility
      droppable: false
    };
  }

  return {
    draggable: (_localDisabled$dragga = localDisabled == null ? void 0 : localDisabled.draggable) != null ? _localDisabled$dragga : globalDisabled.draggable,
    droppable: (_localDisabled$droppa = localDisabled == null ? void 0 : localDisabled.droppable) != null ? _localDisabled$droppa : globalDisabled.droppable
  };
}

function hasSortableData(entry) {
  if (!entry) {
    return false;
  }

  const data = entry.data.current;

  if (data && 'sortable' in data && typeof data.sortable === 'object' && 'containerId' in data.sortable && 'items' in data.sortable && 'index' in data.sortable) {
    return true;
  }

  return false;
}

const directions = [KeyboardCode.Down, KeyboardCode.Right, KeyboardCode.Up, KeyboardCode.Left];
const sortableKeyboardCoordinates = (event, _ref) => {
  let {
    context: {
      active,
      collisionRect,
      droppableRects,
      droppableContainers,
      over,
      scrollableAncestors
    }
  } = _ref;

  if (directions.includes(event.code)) {
    event.preventDefault();

    if (!active || !collisionRect) {
      return;
    }

    const filteredContainers = [];
    droppableContainers.getEnabled().forEach(entry => {
      if (!entry || entry != null && entry.disabled) {
        return;
      }

      const rect = droppableRects.get(entry.id);

      if (!rect) {
        return;
      }

      switch (event.code) {
        case KeyboardCode.Down:
          if (collisionRect.top < rect.top) {
            filteredContainers.push(entry);
          }

          break;

        case KeyboardCode.Up:
          if (collisionRect.top > rect.top) {
            filteredContainers.push(entry);
          }

          break;

        case KeyboardCode.Left:
          if (collisionRect.left > rect.left) {
            filteredContainers.push(entry);
          }

          break;

        case KeyboardCode.Right:
          if (collisionRect.left < rect.left) {
            filteredContainers.push(entry);
          }

          break;
      }
    });
    const collisions = closestCorners({
      active,
      collisionRect: collisionRect,
      droppableRects,
      droppableContainers: filteredContainers,
      pointerCoordinates: null
    });
    let closestId = getFirstCollision(collisions, 'id');

    if (closestId === (over == null ? void 0 : over.id) && collisions.length > 1) {
      closestId = collisions[1].id;
    }

    if (closestId != null) {
      const activeDroppable = droppableContainers.get(active.id);
      const newDroppable = droppableContainers.get(closestId);
      const newRect = newDroppable ? droppableRects.get(newDroppable.id) : null;
      const newNode = newDroppable == null ? void 0 : newDroppable.node.current;

      if (newNode && newRect && activeDroppable && newDroppable) {
        const newScrollAncestors = getScrollableAncestors(newNode);
        const hasDifferentScrollAncestors = newScrollAncestors.some((element, index) => scrollableAncestors[index] !== element);
        const hasSameContainer = isSameContainer(activeDroppable, newDroppable);
        const isAfterActive = isAfter(activeDroppable, newDroppable);
        const offset = hasDifferentScrollAncestors || !hasSameContainer ? {
          x: 0,
          y: 0
        } : {
          x: isAfterActive ? collisionRect.width - newRect.width : 0,
          y: isAfterActive ? collisionRect.height - newRect.height : 0
        };
        const rectCoordinates = {
          x: newRect.left,
          y: newRect.top
        };
        const newCoordinates = offset.x && offset.y ? rectCoordinates : subtract(rectCoordinates, offset);
        return newCoordinates;
      }
    }
  }

  return undefined;
};

function isSameContainer(a, b) {
  if (!hasSortableData(a) || !hasSortableData(b)) {
    return false;
  }

  return a.data.current.sortable.containerId === b.data.current.sortable.containerId;
}

function isAfter(a, b) {
  if (!hasSortableData(a) || !hasSortableData(b)) {
    return false;
  }

  if (!isSameContainer(a, b)) {
    return false;
  }

  return a.data.current.sortable.index < b.data.current.sortable.index;
}

export { SortableContext, arrayMove, arraySwap, defaultAnimateLayoutChanges, defaultNewIndexGetter, hasSortableData, horizontalListSortingStrategy, rectSortingStrategy, rectSwappingStrategy, sortableKeyboardCoordinates, useSortable, verticalListSortingStrategy };
//# sourceMappingURL=sortable.esm.js.map
