import { GraphQLError } from 'graphql';
import { LogStep, LogAction, LogFunction } from './logging';

export class ApolloError extends Error implements GraphQLError {
  public extensions: Record<string, any>;
  readonly name;
  readonly locations;
  readonly path;
  readonly source;
  readonly positions;
  readonly nodes;
  public originalError;

  [key: string]: any;

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

    if (properties) {
      Object.keys(properties).forEach(key => {
        this[key] = properties[key];
      });
    }

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

    //extensions are flattened to be included in the root of GraphQLError's, so
    //don't add properties to extensions
    this.extensions = { code };
  }
}

function enrichError(error: Partial<GraphQLError>, debug: boolean = false) {
  const expanded = {} as any;
  // follows similar structure to https://github.com/graphql/graphql-js/blob/master/src/error/GraphQLError.js#L145-L193
  // with the addition of name
  Object.defineProperties(expanded, {
    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 && error.extensions.code) || 'INTERNAL_SERVER_ERROR',
    exception: {
      ...(error.extensions && 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) {
    expanded.extensions.exception.stacktrace =
      (error.originalError &&
        error.originalError.stack &&
        error.originalError.stack.split('\n')) ||
      (error.stack && error.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;
  errorClass?: typeof ApolloError;
}

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

  //copy enumerable keys
  Object.keys(error).forEach(key => {
    copy[key] = error[key];
  });

  //extensions are non enumerable, so copy them directly
  copy.extensions = {
    ...copy.extensions,
    ...error.extensions,
  };

  //Fallback on default for code
  if (!copy.extensions.code) {
    copy.extensions.code = (options && 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[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) {
    super(message, 'UNAUTHENTICATED');

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

export class ForbiddenError extends ApolloError {
  constructor(message: string) {
    super(message, 'FORBIDDEN');

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

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

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

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

  const flattenedErrors = [];
  errors.forEach(error => {
    // 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
    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 = flattenedErrors.map(error =>
    enrichError(error, debug),
  );

  if (!formatter) {
    return enrichedErrors;
  }

  return enrichedErrors.map(error => {
    try {
      return formatter(error);
    } catch (err) {
      logFunction &&
        logFunction({
          action: LogAction.cleanup,
          step: LogStep.status,
          data: err,
          key: 'error',
        });

      if (debug) {
        return enrichError(err, debug);
      } else {
        //obscure error
        const newError = fromGraphQLError(
          new GraphQLError('Internal server error'),
        );
        return enrichError(newError, debug);
      }
    }
  }) as Array<ApolloError>;
}