/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

/**
 * `ExtensionHostProvider` — React context for the viewer's extension
 * host service.
 *
 * Sits inside `<BimProvider>` so it can pull the live `BimContext`
 * out of the existing SDK plumbing. The service is constructed once
 * on mount, initialised lazily (we kick `init()` on the first commit
 * and surface the loaded statuses to listeners), and disposed on
 * unmount — though in practice the viewer lives for the whole tab
 * session so unmount is rare.
 *
 * Components consume the service via `useExtensionHost()` (everything
 * the user can do) or the specialised hooks
 * `useSlotContributions(slot)` and `useInstalledExtensions()`.
 */

import { createContext, useContext, useEffect, useMemo, useState, type ReactNode } from 'react';
import { useBim } from './BimProvider.js';
import { ExtensionHostService } from '@/services/extensions/host.js';
import { isSafeMode } from '@/lib/safe-mode';
import { toast } from '@/components/ui/toast';

const ExtensionHostContext = createContext<ExtensionHostService | null>(null);

interface ExtensionHostProviderProps {
  children: ReactNode;
}

export function ExtensionHostProvider({ children }: ExtensionHostProviderProps) {
  const bim = useBim();
  // Service identity must be stable across renders so subscribers don't
  // tear themselves down on every commit.
  const service = useMemo(() => new ExtensionHostService({ sdk: bim }), [bim]);

  const [, forceRender] = useState(0);
  useEffect(() => {
    if (isSafeMode()) {
      // Safe mode: skip auto-activation. Service still constructs so
      // the user can run uninstall / disable / repair from the UI; we
      // just don't fire onStartup or load extension code.
      console.info('[ExtensionHostProvider] safe mode — skipping init().');
      return service.onChange(() => forceRender((n) => n + 1));
    }
    service.init()
      .then((statuses) => {
        // Partial-failure path: init() succeeded overall but one or
        // more extensions failed to load. Surface a single toast that
        // points at the Repair queue — repeated per-extension toasts
        // would be noisy on a cold boot with many extensions.
        const failed = statuses.filter((s) => !s.ok);
        if (failed.length > 0) {
          const label = failed.length === 1
            ? `Extension "${failed[0].id}" failed to load.`
            : `${failed.length} extensions failed to load.`;
          toast.error(`${label} Open the Extensions panel → Repair queue to retry.`);
        }
      })
      .catch((err) => {
        console.error('[ExtensionHostProvider] init failed:', err);
        const message = err instanceof Error ? err.message : String(err);
        toast.error(
          `Extension system failed to start: ${message}. Installed extensions ` +
          `may be unavailable — open the Extensions panel to recover.`,
        );
      });
    return service.onChange(() => forceRender((n) => n + 1));
  }, [service]);

  useEffect(() => {
    return () => {
      service.dispose().catch((err) => {
        console.error('[ExtensionHostProvider] dispose failed:', err);
      });
    };
  }, [service]);

  return (
    <ExtensionHostContext.Provider value={service}>
      {children}
    </ExtensionHostContext.Provider>
  );
}

/**
 * Access the extension host service. Throws if used outside
 * `<ExtensionHostProvider>`.
 */
export function useExtensionHost(): ExtensionHostService {
  const ctx = useContext(ExtensionHostContext);
  if (!ctx) {
    throw new Error('useExtensionHost() must be used within an <ExtensionHostProvider>');
  }
  return ctx;
}

/** Same as useExtensionHost but returns null instead of throwing. Useful for code paths that may or may not be inside the provider. */
export function useOptionalExtensionHost(): ExtensionHostService | null {
  return useContext(ExtensionHostContext);
}