import { Clip, TimelineClipDropFailureReason, TimelineReadonly, TimelineTrackGeometryOptions, TimelineTrackHitTestResult, Track, TrackHitTestInput } from "@techsquidtv/canvas-timeline-core";
//#region src/hooks/tracks/useTimelineTrackDropTargets.d.ts
/**
 * Context passed to custom clip track-drop guards.
 *
 * @remarks
 *
 * The context contains the clip being moved, the source row captured at drag
 * start, and the candidate target row currently under the pointer. Use it to
 * express app policy such as visual-only tracks, audio-only tracks, locked
 * groups, or modifier-key cross-kind moves.
 *
 * target tracks.
 */
interface TimelineTrackDropContext {
  /** Clip being moved. */
  clip: TimelineReadonly<Clip>;
  /** Track that contained the clip at drag start. */
  sourceTrack: TimelineReadonly<Track>;
  /** Candidate destination track. */
  targetTrack: TimelineReadonly<Track>;
  /** Source track index at drag start. */
  sourceTrackIndex: number;
  /** Candidate destination track index. */
  targetTrackIndex: number;
}
/** Result of resolving whether a clip may drop on a track. */
interface TimelineTrackDropResult {
  /** Whether the target track accepts the clip. */
  canDrop: boolean;
  /** Machine-readable failure reason when `canDrop` is false. */
  reason: TimelineClipDropFailureReason | null;
  /** Whether the engine should permit a cross-kind transfer. */
  allowCrossKindTrackMove: boolean;
}
/**
 * Custom policy for accepting or rejecting track drop targets.
 *
 * target tracks.
 */
type TimelineTrackDropGuard = (context: TimelineTrackDropContext) => boolean | TimelineTrackDropResult;
/**
 * Options accepted by `useTimelineTrackDropTargets`.
 *
 * @remarks
 *
 * Geometry options should match the renderer and interaction layer. The optional
 * guard runs after built-in checks for missing, locked, and same-kind tracks.
 *
 *
 * @see {@link TimelineTrackDropGuard}
 * @see {@link useTimelineClipDrag}
 */
interface UseTimelineTrackDropTargetsOptions extends TimelineTrackGeometryOptions {
  /** Optional app policy for accepting, rejecting, or expanding drop targets. */
  canDropClipOnTrack?: TimelineTrackDropGuard;
}
/**
 * Result returned by `useTimelineTrackDropTargets`.
 *
 * @remarks
 *
 * Use this result to build custom track-row drop previews, or indirectly through
 * {@link useTimelineClipDrag}. `trackTargets` are viewport-space rows in
 * timeline order and `canDropClipOnTrack` applies both engine and app policy.
 *
 */
interface UseTimelineTrackDropTargetsResult {
  /** Viewport-space track rows in timeline order. */
  trackTargets: TimelineTrackHitTestResult[];
  /** Hit-tests timeline tracks in viewport coordinates. */
  getTrackAtViewportPoint: (input: TrackHitTestInput) => TimelineTrackHitTestResult | null;
  /** Resolves whether one clip may drop on one candidate track. */
  canDropClipOnTrack: (clipId: string, targetTrackId: string, sourceTrackId?: string) => TimelineTrackDropResult;
}
/**
 * Builds headless track drop targets for cross-track clip movement.
 *
 * @remarks
 *
 * This hook is a geometry and policy helper for custom clip drag layers. It
 * does not start pointer capture or mutate clips on its own; combine it with
 * {@link useTimelineClipDrag} or your own pointer lifecycle when building custom
 * interaction chrome.
 *
 * @param options - Track geometry and optional drop policy used to resolve compatible tracks.
 * @returns Track hit targets, viewport hit testing, and drop-policy resolution helpers.
 *
 * @example
 * ```tsx
 * import { useTimelineTrackDropTargets } from '@techsquidtv/canvas-timeline-react';
 *
 * export function TrackDropOverlay({ clipId }: { clipId: string }) {
 *   const targets = useTimelineTrackDropTargets({
 *     canDropClipOnTrack: ({ sourceTrack, targetTrack }) => sourceTrack.kind === targetTrack.kind,
 *   });
 *
 *   return targets.trackTargets.map((target) => {
 *     const result = targets.canDropClipOnTrack(clipId, target.track.id);
 *
 *     return (
 *       <div key={target.track.id} data-valid-drop-target={result.canDrop}>
 *         {target.track.name ?? target.track.id}
 *       </div>
 *     );
 *   });
 * }
 * ```
 *
 * @see {@link TimelineTrackDropContext}
 * @see {@link useTimelineClipDrag}
 * @see {@link https://canvastimeline.com/docs/tracks-and-clips | Tracks and clips}
 */
declare function useTimelineTrackDropTargets(options?: UseTimelineTrackDropTargetsOptions): UseTimelineTrackDropTargetsResult;
//#endregion
export { TimelineTrackDropContext, TimelineTrackDropGuard, TimelineTrackDropResult, UseTimelineTrackDropTargetsOptions, UseTimelineTrackDropTargetsResult, useTimelineTrackDropTargets };
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