/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { useState, useCallback, useEffect } from 'react';
import type { LoadedSettings, SettingScope } from '../../config/settings.js';
import type { Config } from '@qwen-code/qwen-code-core';
import {
  AuthType,
  clearCachedCredentialFile,
  getErrorMessage,
  logAuth,
  AuthEvent,
} from '@qwen-code/qwen-code-core';
import { AuthState } from '../types.js';
import { useQwenAuth } from '../hooks/useQwenAuth.js';
import type { OpenAICredentials } from '../components/OpenAIKeyPrompt.js';

export type { QwenAuthState } from '../hooks/useQwenAuth.js';

export const useAuthCommand = (settings: LoadedSettings, config: Config) => {
  const unAuthenticated =
    settings.merged.security?.auth?.selectedType === undefined;

  const [authState, setAuthState] = useState<AuthState>(
    unAuthenticated ? AuthState.Updating : AuthState.Unauthenticated,
  );

  const [authError, setAuthError] = useState<string | null>(null);

  const [isAuthenticating, setIsAuthenticating] = useState(false);
  const [isAuthDialogOpen, setIsAuthDialogOpen] = useState(unAuthenticated);
  const [pendingAuthType, setPendingAuthType] = useState<AuthType | undefined>(
    undefined,
  );

  const { qwenAuthState, cancelQwenAuth } = useQwenAuth(
    pendingAuthType,
    isAuthenticating,
  );

  const onAuthError = useCallback(
    (error: string | null) => {
      setAuthError(error);
      if (error) {
        setAuthState(AuthState.Updating);
        setIsAuthDialogOpen(true);
      }
    },
    [setAuthError, setAuthState],
  );

  const handleAuthFailure = useCallback(
    (error: unknown) => {
      setIsAuthenticating(false);
      const errorMessage = `Failed to authenticate. Message: ${getErrorMessage(error)}`;
      onAuthError(errorMessage);

      // Log authentication failure
      if (pendingAuthType) {
        const authEvent = new AuthEvent(
          pendingAuthType,
          'manual',
          'error',
          errorMessage,
        );
        logAuth(config, authEvent);
      }
    },
    [onAuthError, pendingAuthType, config],
  );

  const handleAuthSuccess = useCallback(
    async (
      authType: AuthType,
      scope: SettingScope,
      credentials?: OpenAICredentials,
    ) => {
      try {
        settings.setValue(scope, 'security.auth.selectedType', authType);

        // Only update credentials if not switching to QWEN_OAUTH,
        // so that OpenAI credentials are preserved when switching to QWEN_OAUTH.
        if (authType !== AuthType.QWEN_OAUTH && credentials) {
          if (credentials?.apiKey != null) {
            settings.setValue(
              scope,
              'security.auth.apiKey',
              credentials.apiKey,
            );
          }
          if (credentials?.baseUrl != null) {
            settings.setValue(
              scope,
              'security.auth.baseUrl',
              credentials.baseUrl,
            );
          }
          if (credentials?.model != null) {
            settings.setValue(scope, 'model.name', credentials.model);
          }
          await clearCachedCredentialFile();
        }
      } catch (error) {
        handleAuthFailure(error);
        return;
      }

      setAuthError(null);
      setAuthState(AuthState.Authenticated);
      setPendingAuthType(undefined);
      setIsAuthDialogOpen(false);
      setIsAuthenticating(false);

      // Log authentication success
      const authEvent = new AuthEvent(authType, 'manual', 'success');
      logAuth(config, authEvent);
    },
    [settings, handleAuthFailure, config],
  );

  const performAuth = useCallback(
    async (
      authType: AuthType,
      scope: SettingScope,
      credentials?: OpenAICredentials,
    ) => {
      try {
        await config.refreshAuth(authType);
        handleAuthSuccess(authType, scope, credentials);
      } catch (e) {
        handleAuthFailure(e);
      }
    },
    [config, handleAuthSuccess, handleAuthFailure],
  );

  const handleAuthSelect = useCallback(
    async (
      authType: AuthType | undefined,
      scope: SettingScope,
      credentials?: OpenAICredentials,
    ) => {
      if (!authType) {
        setIsAuthDialogOpen(false);
        setAuthError(null);
        return;
      }

      setPendingAuthType(authType);
      setAuthError(null);
      setIsAuthDialogOpen(false);
      setIsAuthenticating(true);

      if (authType === AuthType.USE_OPENAI) {
        if (credentials) {
          config.updateCredentials({
            apiKey: credentials.apiKey,
            baseUrl: credentials.baseUrl,
            model: credentials.model,
          });
          await performAuth(authType, scope, credentials);
        }
        return;
      }

      await performAuth(authType, scope);
    },
    [config, performAuth],
  );

  const openAuthDialog = useCallback(() => {
    setIsAuthDialogOpen(true);
  }, []);

  const cancelAuthentication = useCallback(() => {
    if (isAuthenticating && pendingAuthType === AuthType.QWEN_OAUTH) {
      cancelQwenAuth();
    }

    // Log authentication cancellation
    if (isAuthenticating && pendingAuthType) {
      const authEvent = new AuthEvent(pendingAuthType, 'manual', 'cancelled');
      logAuth(config, authEvent);
    }

    // Do not reset pendingAuthType here, persist the previously selected type.
    setIsAuthenticating(false);
    setIsAuthDialogOpen(true);
    setAuthError(null);
  }, [isAuthenticating, pendingAuthType, cancelQwenAuth, config]);

  /**
   /**
    * We previously used a useEffect to trigger authentication automatically when
    * settings.security.auth.selectedType changed. This caused problems: if authentication failed,
    * the UI could get stuck, since settings.json would update before success. Now, we
    * update selectedType in settings only when authentication fully succeeds.
    * Authentication is triggered explicitly—either during initial app startup or when the
    * user switches methods—not reactively through settings changes. This avoids repeated
    * or broken authentication cycles.
    */
  useEffect(() => {
    const defaultAuthType = process.env['QWEN_DEFAULT_AUTH_TYPE'];
    if (
      defaultAuthType &&
      ![AuthType.QWEN_OAUTH, AuthType.USE_OPENAI].includes(
        defaultAuthType as AuthType,
      )
    ) {
      onAuthError(
        `Invalid QWEN_DEFAULT_AUTH_TYPE value: "${defaultAuthType}". Valid values are: ${[AuthType.QWEN_OAUTH, AuthType.USE_OPENAI].join(', ')}`,
      );
    }
  }, [onAuthError]);

  return {
    authState,
    setAuthState,
    authError,
    onAuthError,
    isAuthDialogOpen,
    isAuthenticating,
    pendingAuthType,
    qwenAuthState,
    handleAuthSelect,
    openAuthDialog,
    cancelAuthentication,
  };
};