"use client";

import { useLayoutEffect, useRef, useState } from 'react';
import { createOrgChart } from '@hm-design/org-chart';
import type { OrgChartAutoLayoutOptions, OrgChartDataSource, OrgChartHandle, OrgChartInteractionOptions, OrgChartOptions } from '@hm-design/org-chart';
import type { OrgChartEmployeeSelection, OrgChartProps } from './types.js';

function annotateEmployeeCards(shadow: ShadowRoot, popup: NonNullable<OrgChartProps['employeePopup']>, customCallback: boolean) {
  const actionable = customCallback || popup !== 'none';
  for (const card of shadow.querySelectorAll<HTMLElement>('.hm-orgchart-employee')) {
    const name = card.querySelector('.hm-orgchart-person-name')?.textContent ?? '';
    const position = card.querySelector('.hm-orgchart-person-role')?.textContent ?? '';
    // Auto cards also provide keyboard movement when the information popup is
    // disabled; popup ownership must not remove that Core keyboard entry point.
    card.tabIndex = 0;
    if (actionable) card.setAttribute('role', 'button');
    else card.removeAttribute('role');
    card.setAttribute('aria-label', `${name} ${position}${actionable ? ' 직원 정보 보기' : ''}`.trim());
    if (actionable && !customCallback) card.setAttribute('aria-haspopup', 'dialog');
    else card.removeAttribute('aria-haspopup');
  }
}

// Core captures option objects by value. Compare them the same way so a parent
// re-render with equal inline literals neither remounts nor re-fits the chart.
const optionKey = (value: unknown) => JSON.stringify(value ?? null);

interface Instance {
  readonly handle: OrgChartHandle;
  readonly generation: number;
  source: OrgChartDataSource;
  autoLayout: OrgChartAutoLayoutOptions | undefined;
  interactions: OrgChartInteractionOptions | undefined;
  selectedCompanyIds: readonly string[] | undefined;
  dragDropEnabled: boolean;
  readonly employeeClick: NonNullable<OrgChartOptions['onEmployeeClick']>;
  employeeCallbackEnabled: boolean;
  popupMode: NonNullable<OrgChartProps['employeePopup']>;
  operation: number;
}

/** A React host for the exact same Core used by Vanilla HTML. */
export function OrgChart({
  dataSource,
  aggregationPolicy,
  stylesheetUrls,
  displayMode,
  layoutMode,
  autoLayout,
  interactions,
  dragDropEnabled = false,
  companyId,
  selectedCompanyIds,
  companyTopNodes,
  employeeConnections,
  zoom,
  presentationMode,
  initialView,
  wheelZoom,
  organizationLinks,
  onEmployeeClick,
  onMove,
  employeePopup = 'core',
  employeePopupAdapter: EmployeePopupAdapter,
  className,
  style,
  onStateChange,
  onLifecycleError,
}: OrgChartProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const instanceRef = useRef<Instance | null>(null);
  const generationRef = useRef(0);
  const [employeeSelection, setEmployeeSelection] = useState<OrgChartEmployeeSelection | null>(null);
  const requestedAdapter = employeePopup === 'hm-dialog' || employeePopup === 'adapter';
  const effectivePopup = requestedAdapter && !EmployeePopupAdapter ? 'core' : employeePopup;
  const committedRef = useRef({ dataSource, onStateChange, onLifecycleError, onEmployeeClick, onMove, employeePopup: effectivePopup });

  // Publish committed values before Core effects run, without letting callback
  // identity changes or abandoned concurrent renders alter Core ownership.
  useLayoutEffect(() => {
    committedRef.current = { dataSource, onStateChange, onLifecycleError, onEmployeeClick, onMove, employeePopup: effectivePopup };
  }, [dataSource, onStateChange, onLifecycleError, onEmployeeClick, onMove, effectivePopup]);

  useLayoutEffect(() => {
    if (layoutMode !== 'auto' || !requestedAdapter || EmployeePopupAdapter || onEmployeeClick) return;
    try {
      committedRef.current.onLifecycleError?.(new Error('OrgChart popup adapter is missing. Use @hm-design/org-chart-react/hm-dialog or supply employeePopupAdapter. Falling back to the Core popup.'));
    } catch { /* Consumer error reporting cannot prevent Core rendering. */ }
  }, [layoutMode, requestedAdapter, EmployeePopupAdapter, Boolean(onEmployeeClick)]);

  const engineStylesheetUrl = stylesheetUrls.engine;
  const coreStylesheetUrl = stylesheetUrls.core;
  const hasEmployeeCallback = typeof onEmployeeClick === 'function';
  const popupMode = layoutMode === 'auto' ? effectivePopup : 'core';
  const adapterOwnsPopup = popupMode !== 'core';
  const hasAdapterCallback = hasEmployeeCallback || popupMode !== 'core';
  const fixedHasEmployeeCallback = layoutMode !== 'auto' && hasEmployeeCallback;

  // Ownership changes are synchronous with the commit: an old request cannot
  // notify between a committed unmount/source change and a passive cleanup.
  useLayoutEffect(() => {
    const container = containerRef.current;
    if (!container) return;
    const generation = ++generationRef.current;
    let handle: OrgChartHandle | undefined;
    let unsubscribe: (() => void) | undefined;
    let popupObserver: MutationObserver | undefined;

    const reportError = (error: unknown) => {
      if (generationRef.current !== generation) return;
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Consumer errors must not leave rejected lifecycle promises. */ }
    };

    try {
      const source = committedRef.current.dataSource;
      const employeeClick: NonNullable<OrgChartOptions['onEmployeeClick']> = (employee, context) => {
        if (generationRef.current !== generation) return;
        const callback = committedRef.current.onEmployeeClick;
        if (callback) callback(employee, context);
        else if (committedRef.current.employeePopup === 'hm-dialog' || committedRef.current.employeePopup === 'adapter') setEmployeeSelection({ employee, context });
      };
      handle = createOrgChart({
        dataSource: source,
        aggregationPolicy,
        stylesheetUrls: { engine: engineStylesheetUrl, core: coreStylesheetUrl },
        displayMode,
        layoutMode,
        autoLayout,
        interactions,
        dragDropEnabled,
        companyId,
        selectedCompanyIds,
        companyTopNodes,
        employeeConnections,
        zoom,
        presentationMode,
        initialView,
        wheelZoom,
        organizationLinks,
        onEmployeeClick: hasAdapterCallback ? employeeClick : undefined,
        onMove: result => {
          if (generationRef.current !== generation) return;
          if (result.moved) setEmployeeSelection(null);
          committedRef.current.onMove?.(result);
        },
      });
      const instance: Instance = { handle, source, autoLayout, interactions, selectedCompanyIds, dragDropEnabled, employeeClick, employeeCallbackEnabled: hasAdapterCallback, popupMode, generation, operation: 1 };
      instanceRef.current = instance;
      unsubscribe = handle.subscribe(state => {
        if (instanceRef.current === instance && generationRef.current === generation) {
          committedRef.current.onStateChange?.(state);
        }
      });
      // Core mount performs the first load. The source effect below compares
      // identity against this record and does not load the initial source again.
      const operation = instance.operation;
      void handle.mount(container).catch(error => {
        if (instanceRef.current === instance && instance.operation === operation) reportError(error);
      });
      const shadow = container.firstElementChild?.shadowRoot;
      if (shadow && layoutMode === 'auto') {
        const annotateCards = () => {
          annotateEmployeeCards(shadow, committedRef.current.employeePopup, Boolean(committedRef.current.onEmployeeClick));
        };
        const Observer = container.ownerDocument.defaultView?.MutationObserver;
        if (Observer) {
          popupObserver = new Observer(annotateCards);
          popupObserver.observe(shadow, { childList: true, subtree: true });
        }
        annotateCards();
      }
    } catch (error) {
      reportError(error);
    }

    return () => {
      // Invalidate callbacks and promise continuations before terminal disposal.
      if (generationRef.current === generation) ++generationRef.current;
      if (instanceRef.current?.generation === generation) instanceRef.current = null;
      popupObserver?.disconnect();
      try { unsubscribe?.(); }
      catch (error) {
        try { committedRef.current.onLifecycleError?.(error); }
        catch { /* A consumer callback cannot prevent terminal Core disposal. */ }
      }
      finally {
        try { handle?.destroy(); }
        catch (error) {
          try { committedRef.current.onLifecycleError?.(error); }
          catch { /* Cleanup still completes when the consumer callback throws. */ }
        }
      }
    };
  }, [optionKey(aggregationPolicy), engineStylesheetUrl, coreStylesheetUrl, displayMode, layoutMode, companyId, optionKey(companyTopNodes), optionKey(employeeConnections), optionKey(zoom), presentationMode, initialView, wheelZoom, optionKey(organizationLinks), fixedHasEmployeeCallback]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    if (!instance || layoutMode !== 'auto' || (instance.employeeCallbackEnabled === hasAdapterCallback && instance.popupMode === popupMode)) return;
    try {
      instance.handle.setEmployeeClickHandler(hasAdapterCallback ? instance.employeeClick : undefined);
      instance.employeeCallbackEnabled = hasAdapterCallback;
      instance.popupMode = popupMode;
    } catch (error) {
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Match Core's callback ownership isolation. */ }
    }
  }, [hasAdapterCallback, popupMode, layoutMode]);

  useLayoutEffect(() => {
    // Close a host-owned popup before committing a changed source/company view;
    // no asynchronous fixture request can leave a stale employee displayed.
    setEmployeeSelection(null);
    const shadow = containerRef.current?.firstElementChild?.shadowRoot;
    if (shadow && layoutMode === 'auto') {
      annotateEmployeeCards(shadow, popupMode, hasEmployeeCallback);
    }
  }, [dataSource, selectedCompanyIds, popupMode, hasEmployeeCallback, layoutMode, adapterOwnsPopup, EmployeePopupAdapter]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    if (!instance || layoutMode !== 'auto' || optionKey(instance.autoLayout) === optionKey(autoLayout)) return;
    instance.autoLayout = autoLayout;
    void instance.handle.setAutoLayout(autoLayout ?? { type: 'tb', hybridStartDepth: 3, initialVisibleDepth: 'all', hybridOrganizationIds: [] }).catch(error => {
      if (instanceRef.current !== instance) return;
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Keep layout setter failures in the lifecycle error contract. */ }
    });
  }, [optionKey(autoLayout), layoutMode]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    if (!instance || layoutMode !== 'auto' || instance.dragDropEnabled === dragDropEnabled) return;
    try {
      instance.handle.setDragDropEnabled(dragDropEnabled);
      instance.dragDropEnabled = dragDropEnabled;
    } catch (error) {
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Keep option changes in the lifecycle error contract. */ }
    }
  }, [dragDropEnabled, layoutMode]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    if (!instance || layoutMode !== 'auto' || optionKey(instance.interactions) === optionKey(interactions)) return;
    instance.interactions = interactions;
    void instance.handle.setInteractions({ collapse: true, zoom: true, pan: true, ...interactions }).catch(error => {
      if (instanceRef.current !== instance) return;
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Interaction controls use the existing lifecycle error contract. */ }
    });
  }, [optionKey(interactions), layoutMode]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    // Mount already passed this selection to Core; only a changed value re-applies.
    if (!instance || layoutMode !== 'auto' || optionKey(instance.selectedCompanyIds) === optionKey(selectedCompanyIds)) return;
    instance.selectedCompanyIds = selectedCompanyIds;
    void instance.handle.setSelectedCompanies(selectedCompanyIds).catch(error => {
      if (instanceRef.current !== instance) return;
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Match other lifecycle callbacks: never leak a rejected Promise. */ }
    });
  }, [optionKey(selectedCompanyIds), layoutMode]);

  useLayoutEffect(() => {
    const instance = instanceRef.current;
    if (!instance || instance.source === dataSource) return;
    instance.source = dataSource;
    const operation = ++instance.operation;
    // Core reload synchronously starts a new revision, aborting/ignoring earlier
    // source requests even when their Promise or engine import is still pending.
    void instance.handle.reload(dataSource).catch(error => {
      if (instanceRef.current !== instance || generationRef.current !== instance.generation || instance.operation !== operation) return;
      try { committedRef.current.onLifecycleError?.(error); }
      catch { /* Consumer errors must not become unhandled Promise rejections. */ }
    });
  }, [dataSource]);

  return <>
    <div ref={containerRef} className={className} style={style} />
    {(popupMode === 'hm-dialog' || popupMode === 'adapter') && EmployeePopupAdapter && !hasEmployeeCallback
      ? <EmployeePopupAdapter selection={employeeSelection} onClose={() => setEmployeeSelection(null)} /> : null}
  </>;
}