import { IRelationMeta } from "../interfaces";
import { FieldDefinitionNode } from "graphql";

export function getRelationMetasFromDefinition(field: FieldDefinitionNode): IRelationMeta {
  if (field.type.kind === "NamedType") {
    return {
      foreignGqlTypeName: field.type.name.value,
      isNonNullType: false,
      isListType: false
    };
  }

  if (field.type.kind === "NonNullType" && field.type.type.kind === "NamedType") {
    return {
      foreignGqlTypeName: field.type.type.name.value,
      isNonNullType: true,
      isListType: false
    };
  }

  if (field.type.kind === "ListType" && field.type.type.kind === "NonNullType" && field.type.type.type.kind === "NamedType") {
    return {
      foreignGqlTypeName: field.type.type.type.name.value,
      isNonNullType: false,
      isListType: true
    };
  }

  if (
    field.type.kind === "NonNullType" &&
    field.type.type.kind === "ListType" &&
    field.type.type.type.kind === "NonNullType" &&
    field.type.type.type.type.kind === "NamedType"
  ) {
    return {
      foreignGqlTypeName: field.type.type.type.type.name.value,
      isNonNullType: true,
      isListType: true
    };
  }

  throw new Error(`Invalid relation for field: ${JSON.stringify(field, null, 2)}`);
}