import { dataService } from "./dataService.js";
import { AdapterError, NotFoundError } from "./utils/errors.js";
import type { GraphQLContext } from "./utils/dataloaders.js";
import { userService } from "./auth/userService.js";
import { logger } from "./monitoring/logger.js";
import type { ContentItem } from "./types/page.js";
import type { User } from "./types/user.js";

/**
 * Fehlerbehandlung für GraphQL Resolver
 */
function handleError(error: unknown): never {
  if (error instanceof NotFoundError) {
    throw error;
  }
  if (error instanceof AdapterError) {
    logger.error("Adapter-Fehler", {
      message: error.message,
      originalError: error.originalError,
    });
    throw new Error(`Datenfehler: ${error.message}`);
  }
  logger.error("Unerwarteter Fehler", { error });
  throw new Error("Ein unerwarteter Fehler ist aufgetreten");
}

/**
 * Wrapper-Funktion für GraphQL Resolver mit automatischem Error Handling
 */
async function withErrorHandling<T>(resolver: () => Promise<T>): Promise<T> {
  try {
    return await resolver();
  } catch (error) {
    handleError(error);
  }
}

/**
 * Formatiert einen User für GraphQL (konvertiert Date zu ISO String)
 */
function formatUserForGraphQL(user: User) {
  return {
    ...user,
    createdAt: user.createdAt.toISOString(),
  };
}

export const resolvers = {
  Query: {
    products: async (
      _: unknown,
      args: { limit?: number },
      context: GraphQLContext
    ) => {
      return withErrorHandling(() => dataService.getProducts(args.limit));
    },
    product: async (
      _: unknown,
      args: { id: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(async () => {
        // Verwende Dataloader für Batch-Loading
        const product = await context.loaders.product.load(args.id);
        if (!product) {
          throw new NotFoundError("Produkt", args.id);
        }
        return product;
      });
    },
    pageSeo: async (
      _: unknown,
      args: { locale?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(() => dataService.getPageSeo(args.locale));
    },
    page: async (
      _: unknown,
      args: { slug: string; locale?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(async () => {
        // Verwende Dataloader für Batch-Loading (mit Locale im Key)
        // Format: "slug:locale" oder "slug" (ohne "page:" Präfix)
        const cacheKey = args.locale
          ? `${args.slug}:${args.locale}`
          : args.slug;
        const page = await context.loaders.page.load(cacheKey);
        if (!page) {
          throw new NotFoundError("Seite", args.slug);
        }
        return page;
      });
    },
    pages: async (
      _: unknown,
      args: { locale?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(() => dataService.getPages(args.locale));
    },
    homepage: async (
      _: unknown,
      args: { locale?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(async () => {
        // Homepage ist immer die Seite mit dem Slug "/"
        const homepage = await dataService.getPage("/", args.locale);
        if (!homepage) {
          throw new NotFoundError("Homepage", "/");
        }
        return homepage;
      });
    },
    navigation: async (
      _: unknown,
      args: { locale?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(() => dataService.getNavigation(args.locale));
    },
    me: async (_: unknown, __: unknown, context: GraphQLContext) => {
      return withErrorHandling(async () => {
        // Gibt aktuellen User zurück (null wenn nicht authentifiziert)
        if (!context.user) {
          return null;
        }
        return formatUserForGraphQL(context.user);
      });
    },
    translations: async (
      _: unknown,
      args: { locale?: string; namespace?: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(() =>
        dataService.getTranslations(args.locale, args.namespace)
      );
    },
  },
  Mutation: {
    register: async (
      _: unknown,
      args: { email: string; password: string; name: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(async () => {
        const result = await userService.register({
          email: args.email,
          password: args.password,
          name: args.name,
        });

        logger.info("User registered via GraphQL", {
          userId: result.user.id,
          email: result.user.email,
        });

        return {
          user: formatUserForGraphQL(result.user),
          token: result.token,
        };
      });
    },
    login: async (
      _: unknown,
      args: { email: string; password: string },
      context: GraphQLContext
    ) => {
      return withErrorHandling(async () => {
        const result = await userService.login({
          email: args.email,
          password: args.password,
        });

        logger.info("User logged in via GraphQL", {
          userId: result.user.id,
          email: result.user.email,
        });

        return {
          user: formatUserForGraphQL(result.user),
          token: result.token,
        };
      });
    },
  },
  ContentItem: {
    __resolveType(obj: ContentItem): string | null {
      // Map für Type-Resolution (Strategy Pattern)
      const typeMap: Record<ContentItem["type"], string> = {
        html: "HTMLContent",
        markdown: "MarkdownContent",
        iframe: "IframeContent",
        imageGallery: "ImageGalleryContent",
        image: "ImageContent",
        quote: "QuoteContent",
        youtubeVideo: "YoutubeVideoContent",
        headline: "HeadlineContent",
      };

      return typeMap[obj.type] || null;
    },
  },
};