/**
 * EditorMenuBar — File / Edit menus for the editor header.
 *
 * The editor grew a single toolbar row where every action, frequent or
 * rare, competed for the same pixels; on small screens the buttons
 * measurably overlapped. The classic fix is the classic desktop split:
 * things you do every minute stay as buttons (Run, Stop, board, Add),
 * things you do a few times per session move into menus. This is those
 * menus.
 *
 * Actions are invoked through the editorCommands registry — their real
 * owners (EditorPage, FileExplorer, EditorToolbar, SimulatorCanvas)
 * register handlers on mount, so nothing here duplicates logic and an
 * item whose owner is not mounted renders disabled. Undo/redo read the
 * canvas history from the store directly, mirroring the canvas buttons.
 *
 * Menubar behaviour follows the desktop convention: click opens, click
 * again closes, hovering a sibling while open switches menus, Escape and
 * outside clicks close.
 */
import React, { useEffect, useRef, useState, useSyncExternalStore } from 'react';
import { useTranslation } from 'react-i18next';
import { useSimulatorStore } from '../../store/useSimulatorStore';
import {
  hasEditorCommand,
  runEditorCommand,
  subscribeEditorCommands,
  getEditorCommandsVersion,
  type EditorCommandId,
} from '../../lib/editorCommands';
import './EditorMenuBar.css';

type Item =
  | { kind: 'command'; id: EditorCommandId; label: string; shortcut?: string }
  | { kind: 'separator' };

export const EditorMenuBar: React.FC = () => {
  const { t } = useTranslation();
  const [open, setOpen] = useState<'file' | 'edit' | null>(null);
  const rootRef = useRef<HTMLDivElement>(null);

  // Re-render when owners (un)register their commands.
  useSyncExternalStore(subscribeEditorCommands, getEditorCommandsVersion);

  const undo = useSimulatorStore((s) => s.undo);
  const redo = useSimulatorStore((s) => s.redo);
  const history = useSimulatorStore((s) => s.history);
  const historyIndex = useSimulatorStore((s) => s.historyIndex);

  useEffect(() => {
    if (!open) return;
    const onDown = (e: MouseEvent): void => {
      if (!rootRef.current?.contains(e.target as Node)) setOpen(null);
    };
    const onKey = (e: KeyboardEvent): void => {
      if (e.key === 'Escape') setOpen(null);
    };
    document.addEventListener('mousedown', onDown);
    document.addEventListener('keydown', onKey);
    return () => {
      document.removeEventListener('mousedown', onDown);
      document.removeEventListener('keydown', onKey);
    };
  }, [open]);

  const fileItems: Item[] = [
    { kind: 'command', id: 'project.new', label: t('editor.menu.newProject', 'New workspace') },
    { kind: 'command', id: 'file.new', label: t('editor.menu.newFile', 'New file') },
    { kind: 'separator' },
    { kind: 'command', id: 'project.open', label: t('editor.menu.open', 'Open project…') },
    {
      kind: 'command',
      id: 'project.save',
      label: t('editor.menu.save', 'Save project'),
      shortcut: 'Ctrl+S',
    },
    { kind: 'separator' },
    { kind: 'command', id: 'project.import', label: t('editor.toolbar.importLabel', 'Import project') },
    { kind: 'command', id: 'project.export', label: t('editor.toolbar.exportLabel', 'Export project (.zip)') },
    { kind: 'command', id: 'project.exportBom', label: t('editor.toolbar.exportBomLabel', 'Bill of Materials (CSV)') },
    {
      kind: 'command',
      id: 'project.exportScreenshot',
      label: t('editor.toolbar.exportScreenshotLabel', 'Schematic image (PNG)'),
    },
  ];

  const editItems: Item[] = [
    { kind: 'separator' }, // placeholder: undo/redo render specially above
    { kind: 'command', id: 'view.reset', label: t('editor.menu.centerView', 'Center canvas view') },
    { kind: 'command', id: 'view.zoomIn', label: t('editor.canvas.zoomIn', 'Zoom in') },
    { kind: 'command', id: 'view.zoomOut', label: t('editor.canvas.zoomOut', 'Zoom out') },
  ];

  const renderCommand = (item: Extract<Item, { kind: 'command' }>): React.ReactNode => (
    <button
      key={item.id}
      role="menuitem"
      className="emb-item"
      disabled={!hasEditorCommand(item.id)}
      onClick={() => {
        setOpen(null);
        runEditorCommand(item.id);
      }}
    >
      <span>{item.label}</span>
      {item.shortcut && <span className="emb-shortcut">{item.shortcut}</span>}
    </button>
  );

  const menu = (which: 'file' | 'edit', label: string, items: Item[]): React.ReactNode => (
    <div className="emb-root" key={which}>
      <button
        className={`emb-trigger${open === which ? ' emb-trigger-open' : ''}`}
        aria-haspopup="menu"
        aria-expanded={open === which}
        onClick={() => setOpen((cur) => (cur === which ? null : which))}
        onMouseEnter={() => setOpen((cur) => (cur && cur !== which ? which : cur))}
      >
        {label}
      </button>
      {open === which && (
        <div className="emb-menu" role="menu">
          {which === 'edit' && (
            <>
              <button
                role="menuitem"
                className="emb-item"
                disabled={historyIndex < 0}
                onClick={() => {
                  setOpen(null);
                  undo();
                }}
              >
                <span>{t('editor.menu.undo', 'Undo')}</span>
                <span className="emb-shortcut">Ctrl+Z</span>
              </button>
              <button
                role="menuitem"
                className="emb-item"
                disabled={historyIndex >= history.length - 1}
                onClick={() => {
                  setOpen(null);
                  redo();
                }}
              >
                <span>{t('editor.menu.redo', 'Redo')}</span>
                <span className="emb-shortcut">Ctrl+Y</span>
              </button>
            </>
          )}
          {items.map((item, i) =>
            item.kind === 'separator' ? (
              <div key={`sep-${i}`} className="emb-separator" />
            ) : (
              renderCommand(item)
            ),
          )}
        </div>
      )}
    </div>
  );

  return (
    <div className="editor-menubar" ref={rootRef}>
      {menu('file', t('editor.menu.file', 'File'), fileItems)}
      {menu('edit', t('editor.menu.edit', 'Edit'), editItems)}
    </div>
  );
};