// @flow strict

import { GraphQLError } from '../../../error/GraphQLError';

import type { EnumValueNode, FieldNode } from '../../../language/ast';
import type { ASTVisitor } from '../../../language/visitor';

import { getNamedType } from '../../../type/definition';

import type { ValidationContext } from '../../ValidationContext';

/**
 * No deprecated
 *
 * A GraphQL document is only valid if all selected fields and all used enum values have not been
 * deprecated.
 *
 * Note: This rule is optional and is not part of the Validation section of the GraphQL
 * Specification. The main purpose of this rule is detection of deprecated usages and not
 * necessarily to forbid their use when querying a service.
 */
export function NoDeprecatedCustomRule(context: ValidationContext): ASTVisitor {
  return {
    Field(node: FieldNode) {
      const fieldDef = context.getFieldDef();
      const parentType = context.getParentType();
      if (parentType && fieldDef?.deprecationReason != null) {
        context.reportError(
          new GraphQLError(
            `The field ${parentType.name}.${fieldDef.name} is deprecated. ` +
              fieldDef.deprecationReason,
            node,
          ),
        );
      }
    },
    EnumValue(node: EnumValueNode) {
      const type = getNamedType(context.getInputType());
      const enumValue = context.getEnumValue();
      if (type && enumValue?.deprecationReason != null) {
        context.reportError(
          new GraphQLError(
            `The enum value "${type.name}.${enumValue.name}" is deprecated. ` +
              enumValue.deprecationReason,
            node,
          ),
        );
      }
    },
  };
}