import {
  ASTNode,
  GraphQLError,
  GraphQLFormattedError,
  Source,
  SourceLocation,
  printError,
  formatError,
} from 'graphql';

declare module 'graphql' {
  export interface GraphQLErrorExtensions {
    exception?: {
      code?: string;
      stacktrace?: ReadonlyArray<string>;
    };
  }
}

// Note: We'd like to switch to `extends GraphQLError` and look forward to doing so
// as soon as we drop support for `graphql` bellow `v15.7.0`.
export class ApolloError extends Error implements GraphQLError {
  public extensions: Record<string, any>;
  override readonly name!: string;
  readonly locations: ReadonlyArray<SourceLocation> | undefined;
  readonly path: ReadonlyArray<string | number> | undefined;
  readonly source: Source | undefined;
  readonly positions: ReadonlyArray<number> | undefined;
  readonly nodes: ReadonlyArray<ASTNode> | undefined;
  public originalError: Error | undefined;

  [key: string]: any;

  constructor(
    message: string,
    code?: string,
    extensions?: Record<string, any>,
  ) {
    super(message);

    // if no name provided, use the default. defineProperty ensures that it stays non-enumerable
    if (!this.name) {
      Object.defineProperty(this, 'name', { value: 'ApolloError' });
    }

    if (extensions?.extensions) {
      throw Error(
        'Pass extensions directly as the third argument of the ApolloError constructor: `new ' +
          'ApolloError(message, code, {myExt: value})`, not `new ApolloError(message, code, ' +
          '{extensions: {myExt: value}})`',
      );
    }

    this.extensions = { ...extensions, code };
  }

  toJSON(): GraphQLFormattedError {
    return formatError(toGraphQLError(this));
  }

  override toString(): string {
    return printError(toGraphQLError(this));
  }

  get [Symbol.toStringTag](): string {
    return this.name;
  }
}

function toGraphQLError(error: ApolloError): GraphQLError {
  return new GraphQLError(
    error.message,
    error.nodes,
    error.source,
    error.positions,
    error.path,
    error.originalError,
    error.extensions,
  );
}

function enrichError(error: Partial<GraphQLError>, debug: boolean = false) {
  // follows similar structure to https://github.com/graphql/graphql-js/blob/main/src/error/GraphQLError.ts#L127-L176
  // with the addition of name
  const expanded = Object.create(Object.getPrototypeOf(error), {
    name: {
      value: error.name,
    },
    message: {
      value: error.message,
      enumerable: true,
      writable: true,
    },
    locations: {
      value: error.locations || undefined,
      enumerable: true,
    },
    path: {
      value: error.path || undefined,
      enumerable: true,
    },
    nodes: {
      value: error.nodes || undefined,
    },
    source: {
      value: error.source || undefined,
    },
    positions: {
      value: error.positions || undefined,
    },
    originalError: {
      value: error.originalError,
    },
  });

  expanded.extensions = {
    ...error.extensions,
    code: error.extensions?.code || 'INTERNAL_SERVER_ERROR',
    exception: {
      ...error.extensions?.exception,
      ...(error.originalError as any),
    },
  };

  // ensure that extensions is not taken from the originalError
  // graphql-js ensures that the originalError's extensions are hoisted
  // https://github.com/graphql/graphql-js/blob/0bb47b2/src/error/GraphQLError.js#L138
  delete expanded.extensions.exception.extensions;
  if (debug && !expanded.extensions.exception.stacktrace) {
    const stack = error.originalError?.stack || error.stack;
    expanded.extensions.exception.stacktrace = stack?.split('\n');
  }

  if (Object.keys(expanded.extensions.exception).length === 0) {
    // remove from printing an empty object
    delete expanded.extensions.exception;
  }

  return expanded as ApolloError;
}

export function toApolloError(
  error: Error & { extensions?: Record<string, any> },
  code: string = 'INTERNAL_SERVER_ERROR',
): Error & { extensions: Record<string, any> } {
  let err = error;
  if (err.extensions) {
    err.extensions.code = code;
  } else {
    err.extensions = { code };
  }
  return err as Error & { extensions: Record<string, any> };
}

export interface ErrorOptions {
  code?: string;
  // This declaration means it takes any "class" that has a constructor that
  // takes a single string, and should be invoked via the `new` operator.
  errorClass?: new (message: string) => ApolloError;
}

export function fromGraphQLError(error: GraphQLError, options?: ErrorOptions) {
  const copy: ApolloError = options?.errorClass
    ? new options.errorClass(error.message)
    : new ApolloError(error.message);

  // copy enumerable keys
  Object.entries(error).forEach(([key, value]) => {
    if (key === 'extensions') {
      return; // extensions are handled bellow
    }
    copy[key] = value;
  });

  // merge extensions instead of just copying them
  copy.extensions = {
    ...copy.extensions,
    ...error.extensions,
  };

  // Fallback on default for code
  if (!copy.extensions.code) {
    copy.extensions.code = options?.code || 'INTERNAL_SERVER_ERROR';
  }

  // copy the original error, while keeping all values non-enumerable, so they
  // are not printed unless directly referenced
  Object.defineProperty(copy, 'originalError', { value: {} });
  Object.getOwnPropertyNames(error).forEach((key) => {
    Object.defineProperty(copy.originalError, key, {
      value: (error as any)[key],
    });
  });

  return copy;
}

export class SyntaxError extends ApolloError {
  constructor(message: string) {
    super(message, 'GRAPHQL_PARSE_FAILED');

    Object.defineProperty(this, 'name', { value: 'SyntaxError' });
  }
}

export class ValidationError extends ApolloError {
  constructor(message: string) {
    super(message, 'GRAPHQL_VALIDATION_FAILED');

    Object.defineProperty(this, 'name', { value: 'ValidationError' });
  }
}

export class AuthenticationError extends ApolloError {
  constructor(message: string, extensions?: Record<string, any>) {
    super(message, 'UNAUTHENTICATED', extensions);

    Object.defineProperty(this, 'name', { value: 'AuthenticationError' });
  }
}

export class ForbiddenError extends ApolloError {
  constructor(message: string, extensions?: Record<string, any>) {
    super(message, 'FORBIDDEN', extensions);

    Object.defineProperty(this, 'name', { value: 'ForbiddenError' });
  }
}

export class PersistedQueryNotFoundError extends ApolloError {
  constructor() {
    super('PersistedQueryNotFound', 'PERSISTED_QUERY_NOT_FOUND');

    Object.defineProperty(this, 'name', {
      value: 'PersistedQueryNotFoundError',
    });
  }
}

export class PersistedQueryNotSupportedError extends ApolloError {
  constructor() {
    super('PersistedQueryNotSupported', 'PERSISTED_QUERY_NOT_SUPPORTED');

    Object.defineProperty(this, 'name', {
      value: 'PersistedQueryNotSupportedError',
    });
  }
}

export class UserInputError extends ApolloError {
  constructor(message: string, extensions?: Record<string, any>) {
    super(message, 'BAD_USER_INPUT', extensions);

    Object.defineProperty(this, 'name', { value: 'UserInputError' });
  }
}

export function formatApolloErrors(
  errors: ReadonlyArray<Error>,
  options?: {
    formatter?: (error: GraphQLError) => GraphQLFormattedError;
    debug?: boolean;
  },
): Array<ApolloError> {
  if (!options) {
    return errors.map((error) => enrichError(error));
  }
  const { formatter, debug } = options;

  // Errors that occur in graphql-tools can contain an errors array that contains the errors thrown in a merged schema
  // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L104-L107
  //
  // They are are wrapped in an extra GraphQL error
  // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L109-L113
  // which calls:
  // https://github.com/graphql/graphql-js/blob/0a30b62964/src/error/locatedError.js#L18-L37
  // Some processing for these nested errors could be done here:
  //
  // if (Array.isArray((error as any).errors)) {
  //   (error as any).errors.forEach(e => flattenedErrors.push(e));
  // } else if (
  //   (error as any).originalError &&
  //   Array.isArray((error as any).originalError.errors)
  // ) {
  //   (error as any).originalError.errors.forEach(e => flattenedErrors.push(e));
  // } else {
  //   flattenedErrors.push(error);
  // }

  const enrichedErrors = errors.map((error) => enrichError(error, debug));
  const makePrintable = (error: GraphQLFormattedError) => {
    if (error instanceof Error) {
      // Error defines its `message` and other fields as non-enumerable, meaning JSON.stringify does not print them.
      const graphQLError = error as GraphQLFormattedError;
      return {
        message: graphQLError.message,
        ...(graphQLError.locations && { locations: graphQLError.locations }),
        ...(graphQLError.path && { path: graphQLError.path }),
        ...(graphQLError.extensions && { extensions: graphQLError.extensions }),
      };
    }
    return error;
  };

  if (!formatter) {
    return enrichedErrors;
  }

  return enrichedErrors.map((error) => {
    try {
      return makePrintable(formatter(error));
    } catch (err) {
      if (debug) {
        // XXX: This cast is pretty sketchy, as other error types can be thrown!
        return enrichError(err as Partial<GraphQLError>, debug);
      } else {
        // obscure error
        const newError = fromGraphQLError(
          new GraphQLError('Internal server error'),
        );
        return enrichError(newError, debug);
      }
    }
  }) as Array<ApolloError>;
}