import { GraphQLError } from '../../error/GraphQLError.mjs';
import {
  isInputObjectType,
  isInterfaceType,
  isObjectType,
} from '../../type/definition.mjs';

/**
 * Unique field definition names
 *
 * A GraphQL complex type is only valid if all its fields are uniquely named.
 */
export function UniqueFieldDefinitionNamesRule(context) {
  const schema = context.getSchema();
  const existingTypeMap = schema ? schema.getTypeMap() : Object.create(null);
  const knownFieldNames = Object.create(null);
  return {
    InputObjectTypeDefinition: checkFieldUniqueness,
    InputObjectTypeExtension: checkFieldUniqueness,
    InterfaceTypeDefinition: checkFieldUniqueness,
    InterfaceTypeExtension: checkFieldUniqueness,
    ObjectTypeDefinition: checkFieldUniqueness,
    ObjectTypeExtension: checkFieldUniqueness,
  };

  function checkFieldUniqueness(node) {
    var _node$fields;

    const typeName = node.name.value;

    if (!knownFieldNames[typeName]) {
      knownFieldNames[typeName] = Object.create(null);
    } // FIXME: https://github.com/graphql/graphql-js/issues/2203

    /* c8 ignore next */

    const fieldNodes =
      (_node$fields = node.fields) !== null && _node$fields !== void 0
        ? _node$fields
        : [];
    const fieldNames = knownFieldNames[typeName];

    for (const fieldDef of fieldNodes) {
      const fieldName = fieldDef.name.value;

      if (hasField(existingTypeMap[typeName], fieldName)) {
        context.reportError(
          new GraphQLError(
            `Field "${typeName}.${fieldName}" already exists in the schema. It cannot also be defined in this type extension.`,
            {
              nodes: fieldDef.name,
            },
          ),
        );
      } else if (fieldNames[fieldName]) {
        context.reportError(
          new GraphQLError(
            `Field "${typeName}.${fieldName}" can only be defined once.`,
            {
              nodes: [fieldNames[fieldName], fieldDef.name],
            },
          ),
        );
      } else {
        fieldNames[fieldName] = fieldDef.name;
      }
    }

    return false;
  }
}

function hasField(type, fieldName) {
  if (isObjectType(type) || isInterfaceType(type) || isInputObjectType(type)) {
    return type.getFields()[fieldName] != null;
  }

  return false;
}