import type { Organization } from '../data/index.js';
import type { OrgChartAutoLayoutOptions, OrgChartAutoLayoutType, OrgChartInteractionOptions } from './types.js';

export function resolveInteractions(options: OrgChartInteractionOptions = {}): Readonly<Required<OrgChartInteractionOptions>> {
  for (const key of ['collapse', 'zoom', 'pan'] as const) {
    if (options[key] !== undefined && typeof options[key] !== 'boolean') throw new TypeError(`interactions.${key} must be boolean`);
  }
  return Object.freeze({ collapse: options.collapse ?? true, zoom: options.zoom ?? true, pan: options.pan ?? true });
}

export interface ResolvedAutoLayout {
  readonly type: OrgChartAutoLayoutType;
  readonly hybridStartDepth: 2 | 3 | 4;
  readonly initialVisibleDepth: 1 | 2 | 3 | 'all';
  readonly hybridOrganizationIds: readonly string[];
}

/** Match installed dabeng 6's mutually exclusive directional/vertical policies. */
export function resolveAutoLayout(options: OrgChartAutoLayoutOptions = {}): ResolvedAutoLayout {
  const type = options.type ?? 'tb';
  const hybridStartDepth = options.hybridStartDepth ?? 3;
  const initialVisibleDepth = options.initialVisibleDepth ?? 'all';
  if (!['tb', 'lr', 'hybrid'].includes(type)) throw new TypeError('autoLayout.type must be tb, lr or hybrid');
  if (![2, 3, 4].includes(hybridStartDepth)) throw new TypeError('autoLayout.hybridStartDepth must be 2, 3 or 4');
  if (![1, 2, 3, 'all'].includes(initialVisibleDepth)) throw new TypeError('autoLayout.initialVisibleDepth must be 1, 2, 3 or all');
  if (options.hybridOrganizationIds !== undefined && (!Array.isArray(options.hybridOrganizationIds) || options.hybridOrganizationIds.some(id => typeof id !== 'string' || !id.trim()))) throw new TypeError('autoLayout.hybridOrganizationIds must contain nonempty organization IDs');
  const hybridOrganizationIds = Object.freeze([...new Set(options.hybridOrganizationIds ?? [])]);
  if (type !== 'tb' && hybridOrganizationIds.length) throw new TypeError('Per-group hybridOrganizationIds are supported only with TB; clear them before selecting LR or Hybrid');
  return Object.freeze({ type, hybridStartDepth, initialVisibleDepth, hybridOrganizationIds });
}

export function autoEngineOptions(layout: ResolvedAutoLayout): { direction: 't2b' | 'l2r'; verticalLevel?: number; visibleLevel: number } {
  // Core owns collapse state and prunes its projection. Upstream visibleLevel
  // would retain hidden descendants that disagree with Core keyboard/state APIs.
  return { direction: layout.type === 'lr' ? 'l2r' : 't2b', visibleLevel: 999,
    ...(layout.type === 'hybrid' ? { verticalLevel: layout.hybridStartDepth } : {}) };
}

/** Apply the visibleLevel policy to new IDs only, keeping user changes stable. */
export function applyInitialVisibility(organizations: readonly Organization[], collapsed: Set<string>, initialized: Set<string>, visibleDepth: ResolvedAutoLayout['initialVisibleDepth'], reset = false): void {
  const valid = new Set(organizations.map(organization => organization.id));
  for (const id of collapsed) if (!valid.has(id) || reset) collapsed.delete(id);
  for (const id of initialized) if (!valid.has(id) || reset) initialized.delete(id);
  const byId = new Map(organizations.map(organization => [organization.id, organization]));
  for (const organization of organizations) {
    if (initialized.has(organization.id)) continue;
    initialized.add(organization.id);
    if (visibleDepth === 'all') continue;
    let depth = 1;
    let current = organization;
    const seen = new Set([current.id]);
    while (current.parentId) {
      const parent = byId.get(current.parentId);
      if (!parent || seen.has(parent.id)) break;
      seen.add(parent.id); current = parent; depth++;
    }
    if (depth >= visibleDepth) collapsed.add(organization.id);
  }
}