import { Injectable } from '@nestjs/common';

import DataLoader from 'dataloader';
import { type APP_LOCALES, SOURCE_LOCALE } from 'twenty-shared/translations';
import { FieldMetadataType } from 'twenty-shared/types';
import { isDefined } from 'twenty-shared/utils';

import { type IndexMetadataInterface } from 'src/engine/metadata-modules/index-metadata/interfaces/index-metadata.interface';

import { I18nService } from 'src/engine/core-modules/i18n/i18n.service';
import { type IDataloaders } from 'src/engine/dataloaders/dataloader.interface';
import { filterMorphRelationDuplicateFields } from 'src/engine/dataloaders/utils/filter-morph-relation-duplicate-fields.util';
import { FIELD_METADATA_STANDARD_OVERRIDES_PROPERTIES } from 'src/engine/metadata-modules/field-metadata/constants/field-metadata-standard-overrides-properties.constant';
import { type FieldMetadataDTO } from 'src/engine/metadata-modules/field-metadata/dtos/field-metadata.dto';
import { RelationDTO } from 'src/engine/metadata-modules/field-metadata/dtos/relation.dto';
import { type FieldMetadataEntity } from 'src/engine/metadata-modules/field-metadata/field-metadata.entity';
import { resolveFieldMetadataStandardOverride } from 'src/engine/metadata-modules/field-metadata/utils/resolve-field-metadata-standard-override.util';
import { WorkspaceManyOrAllFlatEntityMapsCacheService } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.service';
import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
import { findFlatEntityByIdInFlatEntityMapsOrThrow } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps-or-throw.util';
import { findManyFlatEntityByIdInFlatEntityMapsOrThrow } from 'src/engine/metadata-modules/flat-entity/utils/find-many-flat-entity-by-id-in-flat-entity-maps-or-throw.util';
import { findAllOthersMorphRelationFlatFieldMetadatasOrThrow } from 'src/engine/metadata-modules/flat-field-metadata/utils/find-all-others-morph-relation-flat-field-metadatas-or-throw.util';
import { fromFlatFieldMetadataToFieldMetadataDto } from 'src/engine/metadata-modules/flat-field-metadata/utils/from-flat-field-metadata-to-field-metadata-dto.util';
import { fromMorphOrRelationFlatFieldMetadataToRelationDto } from 'src/engine/metadata-modules/flat-field-metadata/utils/from-morph-or-relation-flat-field-metadata-to-relation-dto.util';
import { isFlatFieldMetadataOfType } from 'src/engine/metadata-modules/flat-field-metadata/utils/is-flat-field-metadata-of-type.util';
import { isMorphOrRelationFlatFieldMetadata } from 'src/engine/metadata-modules/flat-field-metadata/utils/is-morph-or-relation-flat-field-metadata.util';
import { fromFlatObjectMetadataToObjectMetadataDto } from 'src/engine/metadata-modules/flat-object-metadata/utils/from-flat-object-metadata-to-object-metadata-dto.util';
import { getMorphNameFromMorphFieldMetadataName } from 'src/engine/metadata-modules/flat-object-metadata/utils/get-morph-name-from-morph-field-metadata-name.util';
import { type IndexFieldMetadataDTO } from 'src/engine/metadata-modules/index-metadata/dtos/index-field-metadata.dto';
import { type IndexMetadataDTO } from 'src/engine/metadata-modules/index-metadata/dtos/index-metadata.dto';
import { ObjectMetadataDTO } from 'src/engine/metadata-modules/object-metadata/dtos/object-metadata.dto';
import { type ObjectMetadataEntity } from 'src/engine/metadata-modules/object-metadata/object-metadata.entity';

export type RelationMetadataLoaderPayload = {
  workspaceId: string;
  fieldMetadata: Pick<FieldMetadataEntity, 'type' | 'id' | 'objectMetadataId'>;
};

export type RelationLoaderPayload = {
  workspaceId: string;
  fieldMetadataId: string;
  objectMetadataId: string;
};

export type MorphRelationLoaderPayload = {
  workspaceId: string;
  fieldMetadataId: string;
  objectMetadataId: string;
};

export type FieldMetadataLoaderPayload = {
  workspaceId: string;
  objectMetadata: Pick<ObjectMetadataEntity, 'id'>;
  locale?: keyof typeof APP_LOCALES;
};

export type IndexMetadataLoaderPayload = {
  workspaceId: string;
  objectMetadata: Pick<ObjectMetadataEntity, 'id'>;
};

export type IndexFieldMetadataLoaderPayload = {
  workspaceId: string;
  objectMetadata: Pick<ObjectMetadataEntity, 'id'>;
  indexMetadata: Pick<IndexMetadataInterface, 'id'>;
};

export type ObjectMetadataLoaderPayload = {
  workspaceId: string;
  objectMetadataId: string;
};

@Injectable()
export class DataloaderService {
  constructor(
    private readonly i18nService: I18nService,
    private readonly flatEntityMapsCacheService: WorkspaceManyOrAllFlatEntityMapsCacheService,
  ) {}

  createLoaders(): IDataloaders {
    const relationLoader = this.createRelationLoader();
    const morphRelationLoader = this.createMorphRelationLoader();
    const fieldMetadataLoader = this.createFieldMetadataLoader();
    const indexMetadataLoader = this.createIndexMetadataLoader();
    const indexFieldMetadataLoader = this.createIndexFieldMetadataLoader();
    const objectMetadataLoader = this.createObjectMetadataLoader();

    return {
      relationLoader,
      morphRelationLoader,
      fieldMetadataLoader,
      indexMetadataLoader,
      indexFieldMetadataLoader,
      objectMetadataLoader,
    };
  }

  private createRelationLoader() {
    return new DataLoader<RelationLoaderPayload, RelationDTO | null>(
      async (dataLoaderParams: RelationLoaderPayload[]) => {
        const relationDtos: Array<RelationDTO | null> = [];
        const workspaceId = dataLoaderParams[0].workspaceId;
        const { flatFieldMetadataMaps, flatObjectMetadataMaps } =
          await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
            {
              workspaceId,
              flatMapsKeys: ['flatFieldMetadataMaps', 'flatObjectMetadataMaps'],
            },
          );

        for (const { fieldMetadataId } of dataLoaderParams) {
          const sourceFlatFieldMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityId: fieldMetadataId,
              flatEntityMaps: flatFieldMetadataMaps,
            });

          if (
            !isFlatFieldMetadataOfType(
              sourceFlatFieldMetadata,
              FieldMetadataType.RELATION,
            )
          ) {
            relationDtos.push(null);
            continue;
          }

          const sourceFlatObjectMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityId: sourceFlatFieldMetadata.objectMetadataId,
              flatEntityMaps: flatObjectMetadataMaps,
            });

          const targetFlatFieldMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityId:
                sourceFlatFieldMetadata.relationTargetFieldMetadataId,
              flatEntityMaps: flatFieldMetadataMaps,
            });

          if (!isMorphOrRelationFlatFieldMetadata(targetFlatFieldMetadata)) {
            relationDtos.push(null);
            continue;
          }

          const targetFlatObjectMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityId: targetFlatFieldMetadata.objectMetadataId,
              flatEntityMaps: flatObjectMetadataMaps,
            });

          if (
            isFlatFieldMetadataOfType(
              targetFlatFieldMetadata,
              FieldMetadataType.MORPH_RELATION,
            )
          ) {
            const morphNameFromMorphFieldMetadataName =
              getMorphNameFromMorphFieldMetadataName({
                morphRelationFlatFieldMetadata: targetFlatFieldMetadata,
                nameSingular: sourceFlatObjectMetadata.nameSingular,
                namePlural: sourceFlatObjectMetadata.namePlural,
              });

            const allMorphFlatFieldMetadatas = [
              targetFlatFieldMetadata,
              ...findAllOthersMorphRelationFlatFieldMetadatasOrThrow({
                flatFieldMetadata: targetFlatFieldMetadata,
                flatFieldMetadataMaps,
                flatObjectMetadata: targetFlatObjectMetadata,
              }),
            ].sort((a, b) => (a.id > b.id ? 1 : -1));

            relationDtos.push(
              fromMorphOrRelationFlatFieldMetadataToRelationDto({
                sourceFlatFieldMetadata,
                sourceFlatObjectMetadata,
                targetFlatFieldMetadata: {
                  ...allMorphFlatFieldMetadatas[0],
                  name: morphNameFromMorphFieldMetadataName,
                },
                targetFlatObjectMetadata,
              }),
            );
            continue;
          }

          relationDtos.push(
            fromMorphOrRelationFlatFieldMetadataToRelationDto({
              sourceFlatFieldMetadata,
              targetFlatFieldMetadata,
              targetFlatObjectMetadata,
              sourceFlatObjectMetadata,
            }),
          );
        }

        return relationDtos;
      },
    );
  }

  private createMorphRelationLoader() {
    return new DataLoader<MorphRelationLoaderPayload, RelationDTO[] | null>(
      async (dataLoaderParams: MorphRelationLoaderPayload[]) => {
        const workspaceId = dataLoaderParams[0].workspaceId;
        const { flatFieldMetadataMaps, flatObjectMetadataMaps } =
          await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
            {
              workspaceId,
              flatMapsKeys: ['flatFieldMetadataMaps', 'flatObjectMetadataMaps'],
            },
          );
        const relationDtos: Array<RelationDTO[] | null> = [];

        for (const { fieldMetadataId } of dataLoaderParams) {
          const morphFlatFieldMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityId: fieldMetadataId,
              flatEntityMaps: flatFieldMetadataMaps,
            });

          if (
            !isFlatFieldMetadataOfType(
              morphFlatFieldMetadata,
              FieldMetadataType.MORPH_RELATION,
            )
          ) {
            relationDtos.push(null);
            continue;
          }

          const sourceFlatObjectMetadata =
            findFlatEntityByIdInFlatEntityMapsOrThrow({
              flatEntityMaps: flatObjectMetadataMaps,
              flatEntityId: morphFlatFieldMetadata.objectMetadataId,
            });

          const relatedMorphFlatFieldMetadatas =
            findAllOthersMorphRelationFlatFieldMetadatasOrThrow({
              flatFieldMetadata: morphFlatFieldMetadata,
              flatFieldMetadataMaps,
              flatObjectMetadata: sourceFlatObjectMetadata,
            });
          const allMorphFlatFieldMetadatas = [
            morphFlatFieldMetadata,
            ...relatedMorphFlatFieldMetadatas,
          ];

          relationDtos.push(
            allMorphFlatFieldMetadatas.flatMap((sourceFlatFieldMetadata) => {
              const targetFlatFieldMetadata =
                findFlatEntityByIdInFlatEntityMapsOrThrow({
                  flatEntityId:
                    sourceFlatFieldMetadata.relationTargetFieldMetadataId,
                  flatEntityMaps: flatFieldMetadataMaps,
                });

              if (
                !isMorphOrRelationFlatFieldMetadata(targetFlatFieldMetadata)
              ) {
                return [];
              }

              const targetFlatObjectMetadata =
                findFlatEntityByIdInFlatEntityMapsOrThrow({
                  flatEntityId:
                    sourceFlatFieldMetadata.relationTargetObjectMetadataId,
                  flatEntityMaps: flatObjectMetadataMaps,
                });

              const morphNameFromMorphFieldMetadataName =
                getMorphNameFromMorphFieldMetadataName({
                  morphRelationFlatFieldMetadata: sourceFlatFieldMetadata,
                  nameSingular: targetFlatObjectMetadata.nameSingular,
                  namePlural: targetFlatObjectMetadata.namePlural,
                });

              return fromMorphOrRelationFlatFieldMetadataToRelationDto({
                sourceFlatFieldMetadata: {
                  ...sourceFlatFieldMetadata,
                  name: morphNameFromMorphFieldMetadataName,
                },
                targetFlatFieldMetadata,
                targetFlatObjectMetadata,
                sourceFlatObjectMetadata,
              });
            }),
          );
        }

        return relationDtos;
      },
    );
  }

  private createIndexMetadataLoader() {
    return new DataLoader<IndexMetadataLoaderPayload, IndexMetadataDTO[]>(
      async (dataLoaderParams: IndexMetadataLoaderPayload[]) => {
        const workspaceId = dataLoaderParams[0].workspaceId;
        const objectMetadataIds = dataLoaderParams.map(
          (dataLoaderParam) => dataLoaderParam.objectMetadata.id,
        );

        const { flatIndexMaps, flatObjectMetadataMaps } =
          await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
            {
              workspaceId,
              flatMapsKeys: ['flatIndexMaps', 'flatObjectMetadataMaps'],
            },
          );

        const indexMetadataCollection = objectMetadataIds.map(
          (objectMetadataId) => {
            const flatObjectMetadata =
              findFlatEntityByIdInFlatEntityMapsOrThrow({
                flatEntityId: objectMetadataId,
                flatEntityMaps: flatObjectMetadataMaps,
              });

            const indexMetadatas =
              findManyFlatEntityByIdInFlatEntityMapsOrThrow({
                flatEntityIds: flatObjectMetadata.indexMetadataIds,
                flatEntityMaps: flatIndexMaps,
              });

            return indexMetadatas.map((indexMetadata) => ({
              ...indexMetadata,
              indexFieldMetadatas: indexMetadata.flatIndexFieldMetadatas,
              createdAt: new Date(indexMetadata.createdAt),
              updatedAt: new Date(indexMetadata.updatedAt),
              id: indexMetadata.id,
              indexWhereClause: indexMetadata.indexWhereClause ?? undefined,
              objectMetadataId,
              workspaceId,
            }));
          },
        );

        return indexMetadataCollection;
      },
    );
  }

  private createFieldMetadataLoader() {
    return new DataLoader<FieldMetadataLoaderPayload, FieldMetadataDTO[]>(
      async (dataLoaderParams: FieldMetadataLoaderPayload[]) => {
        const locale = dataLoaderParams[0].locale;
        const i18nInstance = this.i18nService.getI18nInstance(
          locale ?? SOURCE_LOCALE,
        );
        const workspaceId = dataLoaderParams[0].workspaceId;
        const objectMetadataIds = dataLoaderParams.map(
          (dataLoaderParam) => dataLoaderParam.objectMetadata.id,
        );

        const { flatFieldMetadataMaps, flatObjectMetadataMaps } =
          await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
            {
              workspaceId,
              flatMapsKeys: ['flatFieldMetadataMaps', 'flatObjectMetadataMaps'],
            },
          );

        const fieldMetadataCollection = objectMetadataIds.map(
          (objectMetadataId) => {
            const flatObjectMetadata =
              findFlatEntityByIdInFlatEntityMapsOrThrow({
                flatEntityId: objectMetadataId,
                flatEntityMaps: flatObjectMetadataMaps,
              });
            const objectFlatFieldMetadatas =
              findManyFlatEntityByIdInFlatEntityMapsOrThrow({
                flatEntityIds: flatObjectMetadata.fieldIds,
                flatEntityMaps: flatFieldMetadataMaps,
              });

            const overriddenFieldMetadataEntities =
              objectFlatFieldMetadatas.map((flatFieldMetadata) => {
                return FIELD_METADATA_STANDARD_OVERRIDES_PROPERTIES.reduce(
                  (acc, property) => ({
                    ...acc,
                    [property]: resolveFieldMetadataStandardOverride(
                      {
                        label: flatFieldMetadata.label,
                        description: flatFieldMetadata.description ?? undefined,
                        icon: flatFieldMetadata.icon ?? undefined,
                        isCustom: flatFieldMetadata.isCustom,
                        standardOverrides:
                          flatFieldMetadata.standardOverrides ?? undefined,
                      },
                      property,
                      dataLoaderParams[0].locale,
                      i18nInstance,
                    ),
                  }),
                  flatFieldMetadata,
                );
              });

            const filteredFieldMetadataEntities =
              filterMorphRelationDuplicateFields(
                overriddenFieldMetadataEntities,
              );

            const filteredFieldMetadataEntitiesWithMorphRenamed =
              filteredFieldMetadataEntities.map((flatFieldMetadata) => {
                if (
                  isFlatFieldMetadataOfType(
                    flatFieldMetadata,
                    FieldMetadataType.MORPH_RELATION,
                  )
                ) {
                  const relationTargetObjectMetadata =
                    findFlatEntityByIdInFlatEntityMapsOrThrow({
                      flatEntityId:
                        flatFieldMetadata.relationTargetObjectMetadataId,
                      flatEntityMaps: flatObjectMetadataMaps,
                    });

                  return {
                    ...flatFieldMetadata,
                    name: getMorphNameFromMorphFieldMetadataName({
                      morphRelationFlatFieldMetadata: flatFieldMetadata,
                      nameSingular: relationTargetObjectMetadata.nameSingular,
                      namePlural: relationTargetObjectMetadata.namePlural,
                    }),
                  };
                }

                return flatFieldMetadata;
              });

            return filteredFieldMetadataEntitiesWithMorphRenamed.map(
              fromFlatFieldMetadataToFieldMetadataDto,
            );
          },
        );

        return fieldMetadataCollection;
      },
    );
  }

  private createIndexFieldMetadataLoader() {
    return new DataLoader<
      IndexFieldMetadataLoaderPayload,
      IndexFieldMetadataDTO[]
    >(async (dataLoaderParams: IndexFieldMetadataLoaderPayload[]) => {
      const workspaceId = dataLoaderParams[0].workspaceId;

      const { flatIndexMaps } =
        await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
          {
            workspaceId,
            flatMapsKeys: ['flatIndexMaps'],
          },
        );

      return dataLoaderParams.map(
        ({ indexMetadata: { id: indexMetadataId } }) => {
          const indexMetadataEntity = findFlatEntityByIdInFlatEntityMaps({
            flatEntityId: indexMetadataId,
            flatEntityMaps: flatIndexMaps,
          });

          if (!isDefined(indexMetadataEntity)) {
            return [];
          }

          return indexMetadataEntity.flatIndexFieldMetadatas.map(
            (indexFieldMetadata) => {
              return {
                id: indexFieldMetadata.id,
                fieldMetadataId: indexFieldMetadata.fieldMetadataId,
                order: indexFieldMetadata.order,
                createdAt: new Date(indexFieldMetadata.createdAt),
                updatedAt: new Date(indexFieldMetadata.updatedAt),
                indexMetadataId,
                workspaceId,
              };
            },
          );
        },
      );
    });
  }

  private createObjectMetadataLoader() {
    return new DataLoader<
      ObjectMetadataLoaderPayload,
      ObjectMetadataDTO | null
    >(async (dataLoaderParams: ObjectMetadataLoaderPayload[]) => {
      const workspaceId = dataLoaderParams[0].workspaceId;

      const { flatObjectMetadataMaps } =
        await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
          {
            workspaceId,
            flatMapsKeys: ['flatObjectMetadataMaps'],
          },
        );

      return dataLoaderParams.map((dataLoaderParam) => {
        const flatObjectMetadata = findFlatEntityByIdInFlatEntityMaps({
          flatEntityId: dataLoaderParam.objectMetadataId,
          flatEntityMaps: flatObjectMetadataMaps,
        });

        if (!isDefined(flatObjectMetadata)) {
          return null;
        }

        return fromFlatObjectMetadataToObjectMetadataDto(flatObjectMetadata);
      });
    });
  }
}