/**
 * What Ctrl+C takes (#240): a snapshot of placed objects or of a piece of graph, detached from the
 * model so later edits to the originals do not change what is pasted. Ids are the originals'; the
 * paste commands hand out fresh ones.
 */
import {
  type AnnotationKind,
  findAnnotation,
  type Graph,
  type GraphAnnotation,
  type GraphEdge,
  type GraphNode,
} from '../graph/Graph';
import { editorTransform, parentTransform, positionOf } from '../properties/transform';
import { findObject, subtreeIds, subtreeRoots, treeOrder } from './hierarchy';
import { isLiveInstance, isTemplateContent, resolvedHolder, splitInstanceId } from './instance';
import type { CompositionClip, CompositionItem, SpriteAsset } from './Asset';
import { isCompositionSprite } from './composition';
import type { Mat } from './matrix';
import type { Position } from './Properties';
import type { ObjectHolder, Project } from './Project';
import type { SceneObject } from './SceneObject';

/**
 * A copied subtree's top: where the editor showed it, editor offsets included (#263), and the
 * frame its own rows were meant in.
 */
export interface ClipRoot {
  id: string;
  shown: Position;
  parentMatrix: Mat;
}

export interface ObjectClip {
  kind: 'objects';
  /** Parents before children; a root's `parentId` is the one it had where it was copied. */
  objects: SceneObject[];
  roots: ClipRoot[];
  /** Copied out of a composition (#417): the items of the roots that are items, for a paste there. */
  items?: CompositionItem[];
  /** The sprites of a composition's own the objects wear (#419), back for a paste after a cut. */
  sprites?: SpriteAsset[];
}

export interface GraphClip {
  kind: 'graph';
  nodes: GraphNode[];
  /** Only the edges between copied nodes – a link to a node left behind has nowhere to go. */
  edges: GraphEdge[];
  annotations: { kind: AnnotationKind; annotation: GraphAnnotation }[];
}

/** Animation clips of a composition (#417), for a paste into the same one or another. */
export interface CompositionClipsClip {
  kind: 'compositionClips';
  clips: CompositionClip[];
}

export type Clip = ObjectClip | GraphClip | CompositionClipsClip;

/**
 * The selected objects with everything below them. A placed container keeps showing its template,
 * so its resolved content stays behind; content picked out of a placed container is copied as the
 * ordinary objects it is shown as.
 */
export function copyObjects(
  project: Project,
  holder: ObjectHolder,
  ids: readonly string[],
): ObjectClip | null {
  const view = resolvedHolder(project, holder);
  const roots = subtreeRoots(
    view,
    ids.filter((id) => findObject(view, id)),
  );
  if (roots.length === 0) return null;
  const members = subtreeIds(view, roots);
  const instances = new Set(
    view.objects
      .filter(
        (o) => members.has(o.id) && !isTemplateContent(holder, o.id) && isLiveInstance(project, holder, o),
      )
      .map((o) => o.id),
  );
  const shownByInstance = (id: string) =>
    isTemplateContent(holder, id) && instances.has(splitInstanceId(id)?.instanceId ?? '');
  const objects = treeOrder(view)
    .map((entry) => entry.object)
    .filter((o) => members.has(o.id) && !shownByInstance(o.id))
    .map((o) => ({ ...structuredClone(o), editorOffset: { x: 0, y: 0 } }));
  const items = holder.type === 'composition' ? holder.items.filter((i) => roots.includes(i.id)) : [];
  const worn = new Set(objects.map((o) => o.assetId));
  const sprites = project.assets.filter(isCompositionSprite).filter((a) => worn.has(a.id));
  return {
    kind: 'objects',
    objects,
    ...(items.length > 0 && { items: structuredClone(items) }),
    ...(sprites.length > 0 && { sprites: structuredClone(sprites) }),
    roots: roots.map((id) => {
      const object = findObject(view, id)!;
      return {
        id,
        shown: positionOf(editorTransform(project, view, object)),
        parentMatrix: parentTransform(project, view, object.parentId).m,
      };
    }),
  };
}

export function copyGraph(
  graph: Graph,
  nodeIds: readonly string[],
  annotationIds: readonly string[],
): GraphClip | null {
  const ids = new Set(nodeIds);
  const nodes = graph.nodes.filter((n) => ids.has(n.id));
  const annotations = annotationIds.flatMap((id) => {
    const found = findAnnotation(graph, id);
    return found ? [found] : [];
  });
  if (nodes.length === 0 && annotations.length === 0) return null;
  return structuredClone({
    kind: 'graph',
    nodes,
    edges: graph.edges.filter((e) => ids.has(e.from.node) && ids.has(e.to.node)),
    annotations,
  });
}