import type { GraphNodeId, Project, SceneGraphEdge, SceneGraphNode, SceneId } from '../types';

import { reconcileSceneListOrder } from './sceneListOrder';
import {
  buildStoryRootMap,
  getNodeStoryRoot,
  getSideStoryComponentNodeIds,
  isSideStoryRoot,
} from './sceneGraphLineage';

export type ActiveStorylineSceneEntry = {
  sceneId: SceneId;
  graphNodeId: GraphNodeId;
};

/** Узлы графа, принадлежащие активной сюжетной линии текущего положения. */
export function getActiveStorylineGraphNodeIds(
  nodes: SceneGraphNode[],
  edges: SceneGraphEdge[],
  currentGraphNodeId: GraphNodeId,
): Set<GraphNodeId> {
  const root = getNodeStoryRoot(nodes, edges, currentGraphNodeId);
  if (root === 'main') {
    const rootMap = buildStoryRootMap(nodes, edges);
    const ids = new Set<GraphNodeId>();
    for (const [id, r] of rootMap) {
      if (r === 'main') ids.add(id);
    }
    return ids;
  }
  if (isSideStoryRoot(root)) {
    return getSideStoryComponentNodeIds(nodes, edges, root);
  }
  return new Set();
}

function pickGraphNodeForScene(
  sceneId: SceneId,
  storylineNodeIds: Set<GraphNodeId>,
  nodes: SceneGraphNode[],
  currentGraphNodeId: GraphNodeId | null,
): GraphNodeId | null {
  const matching = nodes.filter((n) => storylineNodeIds.has(n.id) && n.sceneId === sceneId);
  if (matching.length === 0) return null;
  if (currentGraphNodeId && matching.some((n) => n.id === currentGraphNodeId)) {
    return currentGraphNodeId;
  }
  return matching[0]?.id ?? null;
}

/**
 * Сцены активной линии в порядке бокового списка редактора; каждая sceneId — один раз.
 */
export function listActiveStorylineScenes(project: Project): ActiveStorylineSceneEntry[] {
  const currentGraphNodeId = project.currentGraphNodeId;
  if (!currentGraphNodeId) return [];

  const storylineNodeIds = getActiveStorylineGraphNodeIds(
    project.sceneGraphNodes,
    project.sceneGraphEdges,
    currentGraphNodeId,
  );
  if (storylineNodeIds.size === 0) return [];

  const order = reconcileSceneListOrder(project.scenes, project.sceneListOrder);
  const out: ActiveStorylineSceneEntry[] = [];
  for (const sceneId of order) {
    const graphNodeId = pickGraphNodeForScene(
      sceneId,
      storylineNodeIds,
      project.sceneGraphNodes,
      currentGraphNodeId,
    );
    if (graphNodeId) out.push({ sceneId, graphNodeId });
  }
  return out;
}