import {
  CreateCompassComponentRelationship,
  CreateCompassRelationshipInput,
  DeleteCompassComponentRelationship,
  DeleteCompassRelationshipInput,
  Relationship,
} from '@atlassian/forge-graphql-types';
import { GqlSegment } from './types';
import constructGqlSegmentFromArray from '../constructGqlSegmentFromArray';
import generateMutationGql from '../generateMutationGql';

function isRelationshipEqual(a: Relationship, b: Relationship) {
  return a.type === b.type && a.nodeId === b.nodeId;
}

function transformIntoDeleteRelationshipInput(
  item: Relationship,
  componentId: string,
): DeleteCompassRelationshipInput {
  const { type, nodeId } = item;
  return {
    type,
    startNodeId: componentId,
    endNodeId: nodeId,
  };
}

function transformIntoCreateRelationshipInput(
  item: Relationship,
  componentId: string,
): CreateCompassRelationshipInput {
  const { type, nodeId } = item;
  return {
    type,
    startNodeId: componentId,
    endNodeId: nodeId,
  };
}

export default function updateRelationshipsSegment(
  componentId: string,
  oldRelationships: Array<Relationship> = [],
  newRelationships: Array<Relationship> = undefined,
): GqlSegment {
  let segmentAcc = {
    mutation: '',
    parameters: [] as Array<string>,
    variables: {} as Record<string, any>,
  };
  // if newRelationships is null, remove existing relationships
  if (newRelationships === undefined) {
    return segmentAcc;
  }
  newRelationships = newRelationships || [];

  console.log(oldRelationships);
  console.log(newRelationships);
  const relationshipsInBoth = oldRelationships.filter((existingRelationship) =>
    newRelationships.some((newRelationship) =>
      isRelationshipEqual(newRelationship, existingRelationship),
    ),
  );

  const toBeCreated = newRelationships.filter(
    (newRelationship) =>
      !relationshipsInBoth.some((overlapRelationship) =>
        isRelationshipEqual(overlapRelationship, newRelationship),
      ),
  );

  const toBeRemoved = oldRelationships.filter(
    (oldRelationship) =>
      !relationshipsInBoth.some((overlapRelationship) =>
        isRelationshipEqual(overlapRelationship, oldRelationship),
      ),
  );

  const createRelationshipGqlSegment = () =>
    generateMutationGql(
      CreateCompassComponentRelationship,
      'createRelationship',
    );
  const deleteRelationshipGqlSegment = () =>
    generateMutationGql(
      DeleteCompassComponentRelationship,
      'deleteRelationship',
    );

  if (toBeRemoved.length > 0) {
    segmentAcc = constructGqlSegmentFromArray<Relationship>(
      toBeRemoved,
      deleteRelationshipGqlSegment,
      transformIntoDeleteRelationshipInput,
      segmentAcc,
      componentId,
    );
  }
  if (toBeCreated.length > 0) {
    segmentAcc = constructGqlSegmentFromArray<Relationship>(
      toBeCreated,
      createRelationshipGqlSegment,
      transformIntoCreateRelationshipInput,
      segmentAcc,
      componentId,
    );
  }
  return segmentAcc;
}