import { DataSource } from "../data-source/DataSource"
import { FindManyOptions } from "../find-options/FindManyOptions"
import { EntityTarget } from "../common/EntityTarget"
import { ObjectType } from "../common/ObjectType"
import { EntityNotFoundError } from "../error/EntityNotFoundError"
import { QueryRunnerProviderAlreadyReleasedError } from "../error/QueryRunnerProviderAlreadyReleasedError"
import { FindOneOptions } from "../find-options/FindOneOptions"
import { DeepPartial } from "../common/DeepPartial"
import { RemoveOptions } from "../repository/RemoveOptions"
import { SaveOptions } from "../repository/SaveOptions"
import { NoNeedToReleaseEntityManagerError } from "../error/NoNeedToReleaseEntityManagerError"
import { MongoRepository } from "../repository/MongoRepository"
import { TreeRepository } from "../repository/TreeRepository"
import { Repository } from "../repository/Repository"
import { FindOptionsUtils } from "../find-options/FindOptionsUtils"
import { PlainObjectToNewEntityTransformer } from "../query-builder/transformer/PlainObjectToNewEntityTransformer"
import { PlainObjectToDatabaseEntityTransformer } from "../query-builder/transformer/PlainObjectToDatabaseEntityTransformer"
import {
    CustomRepositoryCannotInheritRepositoryError,
    CustomRepositoryNotFoundError,
    TreeRepositoryNotSupportedError,
    TypeORMError,
} from "../error"
import { AbstractRepository } from "../repository/AbstractRepository"
import { QueryRunner } from "../query-runner/QueryRunner"
import { SelectQueryBuilder } from "../query-builder/SelectQueryBuilder"
import { QueryDeepPartialEntity } from "../query-builder/QueryPartialEntity"
import { EntityPersistExecutor } from "../persistence/EntityPersistExecutor"
import { ObjectId } from "../driver/mongodb/typings"
import { InsertResult } from "../query-builder/result/InsertResult"
import { UpdateResult } from "../query-builder/result/UpdateResult"
import { DeleteResult } from "../query-builder/result/DeleteResult"
import { FindOptionsWhere } from "../find-options/FindOptionsWhere"
import { IsolationLevel } from "../driver/types/IsolationLevel"
import { ObjectUtils } from "../util/ObjectUtils"
import { getMetadataArgsStorage } from "../globals"
import { UpsertOptions } from "../repository/UpsertOptions"
import { InstanceChecker } from "../util/InstanceChecker"
import { ObjectLiteral } from "../common/ObjectLiteral"
import { PickKeysByType } from "../common/PickKeysByType"

/**
 * Entity manager supposed to work with any entity, automatically find its repository and call its methods,
 * whatever entity type are you passing.
 */
export class EntityManager {
    readonly "@instanceof" = Symbol.for("EntityManager")

    // -------------------------------------------------------------------------
    // Public Properties
    // -------------------------------------------------------------------------

    /**
     * Connection used by this entity manager.
     */
    readonly connection: DataSource

    /**
     * Custom query runner to be used for operations in this entity manager.
     * Used only in non-global entity manager.
     */
    readonly queryRunner?: QueryRunner

    // -------------------------------------------------------------------------
    // Protected Properties
    // -------------------------------------------------------------------------

    /**
     * Once created and then reused by repositories.
     * Created as a future replacement for the #repositories to provide a bit more perf optimization.
     */
    protected repositories = new Map<EntityTarget<any>, Repository<any>>()

    /**
     * Once created and then reused by repositories.
     */
    protected treeRepositories: TreeRepository<any>[] = []

    /**
     * Plain to object transformer used in create and merge operations.
     */
    protected plainObjectToEntityTransformer =
        new PlainObjectToNewEntityTransformer()

    // -------------------------------------------------------------------------
    // Constructor
    // -------------------------------------------------------------------------

    constructor(connection: DataSource, queryRunner?: QueryRunner) {
        this.connection = connection
        if (queryRunner) {
            this.queryRunner = queryRunner
            // dynamic: this.queryRunner = manager;
            ObjectUtils.assign(this.queryRunner, { manager: this })
        }
    }

    // -------------------------------------------------------------------------
    // Public Methods
    // -------------------------------------------------------------------------

    /**
     * Wraps given function execution (and all operations made there) in a transaction.
     * All database operations must be executed using provided entity manager.
     */
    async transaction<T>(
        runInTransaction: (entityManager: EntityManager) => Promise<T>,
    ): Promise<T>

    /**
     * Wraps given function execution (and all operations made there) in a transaction.
     * All database operations must be executed using provided entity manager.
     */
    async transaction<T>(
        isolationLevel: IsolationLevel,
        runInTransaction: (entityManager: EntityManager) => Promise<T>,
    ): Promise<T>

    /**
     * Wraps given function execution (and all operations made there) in a transaction.
     * All database operations must be executed using provided entity manager.
     */
    async transaction<T>(
        isolationOrRunInTransaction:
            | IsolationLevel
            | ((entityManager: EntityManager) => Promise<T>),
        runInTransactionParam?: (entityManager: EntityManager) => Promise<T>,
    ): Promise<T> {
        const isolation =
            typeof isolationOrRunInTransaction === "string"
                ? isolationOrRunInTransaction
                : undefined
        const runInTransaction =
            typeof isolationOrRunInTransaction === "function"
                ? isolationOrRunInTransaction
                : runInTransactionParam

        if (!runInTransaction) {
            throw new TypeORMError(
                `Transaction method requires callback in second parameter if isolation level is supplied.`,
            )
        }

        if (this.queryRunner && this.queryRunner.isReleased)
            throw new QueryRunnerProviderAlreadyReleasedError()

        // if query runner is already defined in this class, it means this entity manager was already created for a single connection
        // if its not defined we create a new query runner - single connection where we'll execute all our operations
        const queryRunner =
            this.queryRunner || this.connection.createQueryRunner()

        try {
            await queryRunner.startTransaction(isolation)
            const result = await runInTransaction(queryRunner.manager)
            await queryRunner.commitTransaction()
            return result
        } catch (err) {
            try {
                // we throw original error even if rollback thrown an error
                await queryRunner.rollbackTransaction()
            } catch (rollbackError) {}
            throw err
        } finally {
            if (!this.queryRunner)
                // if we used a new query runner provider then release it
                await queryRunner.release()
        }
    }

    /**
     * Executes raw SQL query and returns raw database results.
     */
    async query<T = any>(query: string, parameters?: any[]): Promise<T> {
        return this.connection.query(query, parameters, this.queryRunner)
    }

    /**
     * Creates a new query builder that can be used to build a SQL query.
     */
    createQueryBuilder<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        alias: string,
        queryRunner?: QueryRunner,
    ): SelectQueryBuilder<Entity>

    /**
     * Creates a new query builder that can be used to build a SQL query.
     */
    createQueryBuilder(queryRunner?: QueryRunner): SelectQueryBuilder<any>

    /**
     * Creates a new query builder that can be used to build a SQL query.
     */
    createQueryBuilder<Entity extends ObjectLiteral>(
        entityClass?: EntityTarget<Entity> | QueryRunner,
        alias?: string,
        queryRunner?: QueryRunner,
    ): SelectQueryBuilder<Entity> {
        if (alias) {
            return this.connection.createQueryBuilder(
                entityClass as EntityTarget<Entity>,
                alias,
                queryRunner || this.queryRunner,
            )
        } else {
            return this.connection.createQueryBuilder(
                (entityClass as QueryRunner | undefined) ||
                    queryRunner ||
                    this.queryRunner,
            )
        }
    }

    /**
     * Checks if entity has an id.
     */
    hasId(entity: any): boolean

    /**
     * Checks if entity of given schema name has an id.
     */
    hasId(target: Function | string, entity: any): boolean

    /**
     * Checks if entity has an id by its Function type or schema name.
     */
    hasId(targetOrEntity: any | Function | string, maybeEntity?: any): boolean {
        const target =
            arguments.length === 2 ? targetOrEntity : targetOrEntity.constructor
        const entity = arguments.length === 2 ? maybeEntity : targetOrEntity
        const metadata = this.connection.getMetadata(target)
        return metadata.hasId(entity)
    }

    /**
     * Gets entity mixed id.
     */
    getId(entity: any): any

    /**
     * Gets entity mixed id.
     */
    getId(target: EntityTarget<any>, entity: any): any

    /**
     * Gets entity mixed id.
     */
    getId(targetOrEntity: any | EntityTarget<any>, maybeEntity?: any): any {
        const target =
            arguments.length === 2 ? targetOrEntity : targetOrEntity.constructor
        const entity = arguments.length === 2 ? maybeEntity : targetOrEntity
        const metadata = this.connection.getMetadata(target)
        return metadata.getEntityIdMixedMap(entity)
    }

    /**
     * Creates a new entity instance and copies all entity properties from this object into a new entity.
     * Note that it copies only properties that present in entity schema.
     */
    create<Entity>(
        entityClass: EntityTarget<Entity>,
        plainObject?: DeepPartial<Entity>,
    ): Entity

    /**
     * Creates a new entities and copies all entity properties from given objects into their new entities.
     * Note that it copies only properties that present in entity schema.
     */
    create<Entity>(
        entityClass: EntityTarget<Entity>,
        plainObjects?: DeepPartial<Entity>[],
    ): Entity[]

    /**
     * Creates a new entity instance or instances.
     * Can copy properties from the given object into new entities.
     */
    create<Entity>(
        entityClass: EntityTarget<Entity>,
        plainObjectOrObjects?: DeepPartial<Entity> | DeepPartial<Entity>[],
    ): Entity | Entity[] {
        const metadata = this.connection.getMetadata(entityClass)

        if (!plainObjectOrObjects) return metadata.create(this.queryRunner)

        if (Array.isArray(plainObjectOrObjects))
            return (plainObjectOrObjects as DeepPartial<Entity>[]).map(
                (plainEntityLike) => this.create(entityClass, plainEntityLike),
            )

        const mergeIntoEntity = metadata.create(this.queryRunner)
        this.plainObjectToEntityTransformer.transform(
            mergeIntoEntity,
            plainObjectOrObjects,
            metadata,
            true,
        )
        return mergeIntoEntity
    }

    /**
     * Merges two entities into one new entity.
     */
    merge<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        mergeIntoEntity: Entity,
        ...entityLikes: DeepPartial<Entity>[]
    ): Entity {
        // todo: throw exception if entity manager is released
        const metadata = this.connection.getMetadata(entityClass)
        entityLikes.forEach((object) =>
            this.plainObjectToEntityTransformer.transform(
                mergeIntoEntity,
                object,
                metadata,
            ),
        )
        return mergeIntoEntity
    }

    /**
     * Creates a new entity from the given plain javascript object. If entity already exist in the database, then
     * it loads it (and everything related to it), replaces all values with the new ones from the given object
     * and returns this new entity. This new entity is actually a loaded from the db entity with all properties
     * replaced from the new object.
     */
    async preload<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        entityLike: DeepPartial<Entity>,
    ): Promise<Entity | undefined> {
        const metadata = this.connection.getMetadata(entityClass)
        const plainObjectToDatabaseEntityTransformer =
            new PlainObjectToDatabaseEntityTransformer(this.connection.manager)
        const transformedEntity =
            await plainObjectToDatabaseEntityTransformer.transform(
                entityLike,
                metadata,
            )
        if (transformedEntity)
            return this.merge(
                entityClass as any,
                transformedEntity as Entity,
                entityLike,
            )

        return undefined
    }

    /**
     * Saves all given entities in the database.
     * If entities do not exist in the database then inserts, otherwise updates.
     */
    save<Entity>(entities: Entity[], options?: SaveOptions): Promise<Entity[]>

    /**
     * Saves all given entities in the database.
     * If entities do not exist in the database then inserts, otherwise updates.
     */
    save<Entity>(entity: Entity, options?: SaveOptions): Promise<Entity>

    /**
     * Saves all given entities in the database.
     * If entities do not exist in the database then inserts, otherwise updates.
     */
    save<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entities: T[],
        options: SaveOptions & { reload: false },
    ): Promise<T[]>

    /**
     * Saves all given entities in the database.
     * If entities do not exist in the database then inserts, otherwise updates.
     */
    save<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entities: T[],
        options?: SaveOptions,
    ): Promise<(T & Entity)[]>

    /**
     * Saves a given entity in the database.
     * If entity does not exist in the database then inserts, otherwise updates.
     */
    save<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entity: T,
        options: SaveOptions & { reload: false },
    ): Promise<T>

    /**
     * Saves a given entity in the database.
     * If entity does not exist in the database then inserts, otherwise updates.
     */
    save<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entity: T,
        options?: SaveOptions,
    ): Promise<T & Entity>

    /**
     * Saves a given entity in the database.
     */
    save<Entity extends ObjectLiteral, T extends DeepPartial<Entity>>(
        targetOrEntity: (T | T[]) | EntityTarget<Entity>,
        maybeEntityOrOptions?: T | T[],
        maybeOptions?: SaveOptions,
    ): Promise<T | T[]> {
        // normalize mixed parameters
        let target =
            arguments.length > 1 &&
            (typeof targetOrEntity === "function" ||
                InstanceChecker.isEntitySchema(targetOrEntity) ||
                typeof targetOrEntity === "string")
                ? (targetOrEntity as Function | string)
                : undefined
        const entity: T | T[] = target
            ? (maybeEntityOrOptions as T | T[])
            : (targetOrEntity as T | T[])
        const options = target
            ? maybeOptions
            : (maybeEntityOrOptions as SaveOptions)

        if (InstanceChecker.isEntitySchema(target)) target = target.options.name

        // if user passed empty array of entities then we don't need to do anything
        if (Array.isArray(entity) && entity.length === 0)
            return Promise.resolve(entity)

        // execute save operation
        return new EntityPersistExecutor(
            this.connection,
            this.queryRunner,
            "save",
            target,
            entity,
            options,
        )
            .execute()
            .then(() => entity)
    }

    /**
     * Removes a given entity from the database.
     */
    remove<Entity>(entity: Entity, options?: RemoveOptions): Promise<Entity>

    /**
     * Removes a given entity from the database.
     */
    remove<Entity>(
        targetOrEntity: EntityTarget<Entity>,
        entity: Entity,
        options?: RemoveOptions,
    ): Promise<Entity>

    /**
     * Removes a given entity from the database.
     */
    remove<Entity>(entity: Entity[], options?: RemoveOptions): Promise<Entity>

    /**
     * Removes a given entity from the database.
     */
    remove<Entity>(
        targetOrEntity: EntityTarget<Entity>,
        entity: Entity[],
        options?: RemoveOptions,
    ): Promise<Entity[]>

    /**
     * Removes a given entity from the database.
     */
    remove<Entity extends ObjectLiteral>(
        targetOrEntity: (Entity | Entity[]) | EntityTarget<Entity>,
        maybeEntityOrOptions?: Entity | Entity[],
        maybeOptions?: RemoveOptions,
    ): Promise<Entity | Entity[]> {
        // normalize mixed parameters
        const target =
            arguments.length > 1 &&
            (typeof targetOrEntity === "function" ||
                InstanceChecker.isEntitySchema(targetOrEntity) ||
                typeof targetOrEntity === "string")
                ? (targetOrEntity as Function | string)
                : undefined
        const entity: Entity | Entity[] = target
            ? (maybeEntityOrOptions as Entity | Entity[])
            : (targetOrEntity as Entity | Entity[])
        const options = target
            ? maybeOptions
            : (maybeEntityOrOptions as SaveOptions)

        // if user passed empty array of entities then we don't need to do anything
        if (Array.isArray(entity) && entity.length === 0)
            return Promise.resolve(entity)

        // execute save operation
        return new EntityPersistExecutor(
            this.connection,
            this.queryRunner,
            "remove",
            target,
            entity,
            options,
        )
            .execute()
            .then(() => entity)
    }

    /**
     * Records the delete date of all given entities.
     */
    softRemove<Entity>(
        entities: Entity[],
        options?: SaveOptions,
    ): Promise<Entity[]>

    /**
     * Records the delete date of a given entity.
     */
    softRemove<Entity>(entity: Entity, options?: SaveOptions): Promise<Entity>

    /**
     * Records the delete date of all given entities.
     */
    softRemove<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entities: T[],
        options?: SaveOptions,
    ): Promise<T[]>

    /**
     * Records the delete date of a given entity.
     */
    softRemove<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entity: T,
        options?: SaveOptions,
    ): Promise<T>

    /**
     * Records the delete date of one or many given entities.
     */
    softRemove<Entity extends ObjectLiteral, T extends DeepPartial<Entity>>(
        targetOrEntity: (T | T[]) | EntityTarget<Entity>,
        maybeEntityOrOptions?: T | T[],
        maybeOptions?: SaveOptions,
    ): Promise<T | T[]> {
        // normalize mixed parameters
        let target =
            arguments.length > 1 &&
            (typeof targetOrEntity === "function" ||
                InstanceChecker.isEntitySchema(targetOrEntity) ||
                typeof targetOrEntity === "string")
                ? (targetOrEntity as Function | string)
                : undefined
        const entity: T | T[] = target
            ? (maybeEntityOrOptions as T | T[])
            : (targetOrEntity as T | T[])
        const options = target
            ? maybeOptions
            : (maybeEntityOrOptions as SaveOptions)

        if (InstanceChecker.isEntitySchema(target)) target = target.options.name

        // if user passed empty array of entities then we don't need to do anything
        if (Array.isArray(entity) && entity.length === 0)
            return Promise.resolve(entity)

        // execute soft-remove operation
        return new EntityPersistExecutor(
            this.connection,
            this.queryRunner,
            "soft-remove",
            target,
            entity,
            options,
        )
            .execute()
            .then(() => entity)
    }

    /**
     * Recovers all given entities.
     */
    recover<Entity>(
        entities: Entity[],
        options?: SaveOptions,
    ): Promise<Entity[]>

    /**
     * Recovers a given entity.
     */
    recover<Entity>(entity: Entity, options?: SaveOptions): Promise<Entity>

    /**
     * Recovers all given entities.
     */
    recover<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entities: T[],
        options?: SaveOptions,
    ): Promise<T[]>

    /**
     * Recovers a given entity.
     */
    recover<Entity, T extends DeepPartial<Entity>>(
        targetOrEntity: EntityTarget<Entity>,
        entity: T,
        options?: SaveOptions,
    ): Promise<T>

    /**
     * Recovers one or many given entities.
     */
    recover<Entity extends ObjectLiteral, T extends DeepPartial<Entity>>(
        targetOrEntity: (T | T[]) | EntityTarget<Entity>,
        maybeEntityOrOptions?: T | T[],
        maybeOptions?: SaveOptions,
    ): Promise<T | T[]> {
        // normalize mixed parameters
        let target =
            arguments.length > 1 &&
            (typeof targetOrEntity === "function" ||
                InstanceChecker.isEntitySchema(targetOrEntity) ||
                typeof targetOrEntity === "string")
                ? (targetOrEntity as Function | string)
                : undefined
        const entity: T | T[] = target
            ? (maybeEntityOrOptions as T | T[])
            : (targetOrEntity as T | T[])
        const options = target
            ? maybeOptions
            : (maybeEntityOrOptions as SaveOptions)

        if (InstanceChecker.isEntitySchema(target)) target = target.options.name

        // if user passed empty array of entities then we don't need to do anything
        if (Array.isArray(entity) && entity.length === 0)
            return Promise.resolve(entity)

        // execute recover operation
        return new EntityPersistExecutor(
            this.connection,
            this.queryRunner,
            "recover",
            target,
            entity,
            options,
        )
            .execute()
            .then(() => entity)
    }

    /**
     * Inserts a given entity into the database.
     * Unlike save method executes a primitive operation without cascades, relations and other operations included.
     * Executes fast and efficient INSERT query.
     * Does not check if entity exist in the database, so query will fail if duplicate entity is being inserted.
     * You can execute bulk inserts using this method.
     */
    async insert<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
        entity:
            | QueryDeepPartialEntity<Entity>
            | QueryDeepPartialEntity<Entity>[],
    ): Promise<InsertResult> {
        return this.createQueryBuilder()
            .insert()
            .into(target)
            .values(entity)
            .execute()
    }

    async upsert<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
        entityOrEntities:
            | QueryDeepPartialEntity<Entity>
            | QueryDeepPartialEntity<Entity>[],
        conflictPathsOrOptions: string[] | UpsertOptions<Entity>,
    ): Promise<InsertResult> {
        const metadata = this.connection.getMetadata(target)

        let options: UpsertOptions<Entity>

        if (Array.isArray(conflictPathsOrOptions)) {
            options = {
                conflictPaths: conflictPathsOrOptions,
            }
        } else {
            options = conflictPathsOrOptions
        }

        let entities: QueryDeepPartialEntity<Entity>[]

        if (!Array.isArray(entityOrEntities)) {
            entities = [entityOrEntities]
        } else {
            entities = entityOrEntities
        }

        const conflictColumns = metadata.mapPropertyPathsToColumns(
            Array.isArray(options.conflictPaths)
                ? options.conflictPaths
                : Object.keys(options.conflictPaths),
        )

        const overwriteColumns = metadata.columns.filter(
            (col) =>
                !conflictColumns.includes(col) &&
                entities.some(
                    (entity) =>
                        typeof col.getEntityValue(entity) !== "undefined",
                ),
        )

        return this.createQueryBuilder()
            .insert()
            .into(target)
            .values(entities)
            .orUpdate(
                [...conflictColumns, ...overwriteColumns].map(
                    (col) => col.databaseName,
                ),
                conflictColumns.map((col) => col.databaseName),
                {
                    skipUpdateIfNoValuesChanged:
                        options.skipUpdateIfNoValuesChanged,
                    indexPredicate: options.indexPredicate,
                    upsertType:
                        options.upsertType ||
                        this.connection.driver.supportedUpsertTypes[0],
                },
            )
            .execute()
    }

    /**
     * Updates entity partially. Entity can be found by a given condition(s).
     * Unlike save method executes a primitive operation without cascades, relations and other operations included.
     * Executes fast and efficient UPDATE query.
     * Does not check if entity exist in the database.
     * Condition(s) cannot be empty.
     */
    update<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
        criteria:
            | string
            | string[]
            | number
            | number[]
            | Date
            | Date[]
            | ObjectId
            | ObjectId[]
            | any,
        partialEntity: QueryDeepPartialEntity<Entity>,
    ): Promise<UpdateResult> {
        // if user passed empty criteria or empty list of criterias, then throw an error
        if (
            criteria === undefined ||
            criteria === null ||
            criteria === "" ||
            (Array.isArray(criteria) && criteria.length === 0)
        ) {
            return Promise.reject(
                new TypeORMError(
                    `Empty criteria(s) are not allowed for the update method.`,
                ),
            )
        }

        if (
            typeof criteria === "string" ||
            typeof criteria === "number" ||
            criteria instanceof Date ||
            Array.isArray(criteria)
        ) {
            return this.createQueryBuilder()
                .update(target)
                .set(partialEntity)
                .whereInIds(criteria)
                .execute()
        } else {
            return this.createQueryBuilder()
                .update(target)
                .set(partialEntity)
                .where(criteria)
                .execute()
        }
    }

    /**
     * Deletes entities by a given condition(s).
     * Unlike save method executes a primitive operation without cascades, relations and other operations included.
     * Executes fast and efficient DELETE query.
     * Does not check if entity exist in the database.
     * Condition(s) cannot be empty.
     */
    delete<Entity extends ObjectLiteral>(
        targetOrEntity: EntityTarget<Entity>,
        criteria:
            | string
            | string[]
            | number
            | number[]
            | Date
            | Date[]
            | ObjectId
            | ObjectId[]
            | any,
    ): Promise<DeleteResult> {
        // if user passed empty criteria or empty list of criterias, then throw an error
        if (
            criteria === undefined ||
            criteria === null ||
            criteria === "" ||
            (Array.isArray(criteria) && criteria.length === 0)
        ) {
            return Promise.reject(
                new TypeORMError(
                    `Empty criteria(s) are not allowed for the delete method.`,
                ),
            )
        }

        if (
            typeof criteria === "string" ||
            typeof criteria === "number" ||
            criteria instanceof Date ||
            Array.isArray(criteria)
        ) {
            return this.createQueryBuilder()
                .delete()
                .from(targetOrEntity)
                .whereInIds(criteria)
                .execute()
        } else {
            return this.createQueryBuilder()
                .delete()
                .from(targetOrEntity)
                .where(criteria)
                .execute()
        }
    }

    /**
     * Records the delete date of entities by a given condition(s).
     * Unlike save method executes a primitive operation without cascades, relations and other operations included.
     * Executes fast and efficient DELETE query.
     * Does not check if entity exist in the database.
     * Condition(s) cannot be empty.
     */
    softDelete<Entity extends ObjectLiteral>(
        targetOrEntity: EntityTarget<Entity>,
        criteria:
            | string
            | string[]
            | number
            | number[]
            | Date
            | Date[]
            | ObjectId
            | ObjectId[]
            | any,
    ): Promise<UpdateResult> {
        // if user passed empty criteria or empty list of criterias, then throw an error
        if (
            criteria === undefined ||
            criteria === null ||
            criteria === "" ||
            (Array.isArray(criteria) && criteria.length === 0)
        ) {
            return Promise.reject(
                new TypeORMError(
                    `Empty criteria(s) are not allowed for the delete method.`,
                ),
            )
        }

        if (
            typeof criteria === "string" ||
            typeof criteria === "number" ||
            criteria instanceof Date ||
            Array.isArray(criteria)
        ) {
            return this.createQueryBuilder()
                .softDelete()
                .from(targetOrEntity)
                .whereInIds(criteria)
                .execute()
        } else {
            return this.createQueryBuilder()
                .softDelete()
                .from(targetOrEntity)
                .where(criteria)
                .execute()
        }
    }

    /**
     * Restores entities by a given condition(s).
     * Unlike save method executes a primitive operation without cascades, relations and other operations included.
     * Executes fast and efficient DELETE query.
     * Does not check if entity exist in the database.
     * Condition(s) cannot be empty.
     */
    restore<Entity extends ObjectLiteral>(
        targetOrEntity: EntityTarget<Entity>,
        criteria:
            | string
            | string[]
            | number
            | number[]
            | Date
            | Date[]
            | ObjectId
            | ObjectId[]
            | any,
    ): Promise<UpdateResult> {
        // if user passed empty criteria or empty list of criterias, then throw an error
        if (
            criteria === undefined ||
            criteria === null ||
            criteria === "" ||
            (Array.isArray(criteria) && criteria.length === 0)
        ) {
            return Promise.reject(
                new TypeORMError(
                    `Empty criteria(s) are not allowed for the delete method.`,
                ),
            )
        }

        if (
            typeof criteria === "string" ||
            typeof criteria === "number" ||
            criteria instanceof Date ||
            Array.isArray(criteria)
        ) {
            return this.createQueryBuilder()
                .restore()
                .from(targetOrEntity)
                .whereInIds(criteria)
                .execute()
        } else {
            return this.createQueryBuilder()
                .restore()
                .from(targetOrEntity)
                .where(criteria)
                .execute()
        }
    }

    /**
     * Checks whether any entity exists with the given condition
     */
    exists<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options?: FindManyOptions<Entity>,
    ): Promise<boolean> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder(
            entityClass,
            FindOptionsUtils.extractFindManyOptionsAlias(options) ||
                metadata.name,
        )
            .setFindOptions(options || {})
            .getExists()
    }

    /**
     * Counts entities that match given options.
     * Useful for pagination.
     */
    count<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options?: FindManyOptions<Entity>,
    ): Promise<number> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder(
            entityClass,
            FindOptionsUtils.extractFindManyOptionsAlias(options) ||
                metadata.name,
        )
            .setFindOptions(options || {})
            .getCount()
    }

    /**
     * Counts entities that match given conditions.
     * Useful for pagination.
     */
    countBy<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<number> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder(entityClass, metadata.name)
            .setFindOptions({ where })
            .getCount()
    }

    /**
     * Return the SUM of a column
     */
    sum<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        columnName: PickKeysByType<Entity, number>,
        where?: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<number | null> {
        return this.callAggregateFun(entityClass, "SUM", columnName, where)
    }

    /**
     * Return the AVG of a column
     */
    average<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        columnName: PickKeysByType<Entity, number>,
        where?: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<number | null> {
        return this.callAggregateFun(entityClass, "AVG", columnName, where)
    }

    /**
     * Return the MIN of a column
     */
    minimum<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        columnName: PickKeysByType<Entity, number>,
        where?: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<number | null> {
        return this.callAggregateFun(entityClass, "MIN", columnName, where)
    }

    /**
     * Return the MAX of a column
     */
    maximum<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        columnName: PickKeysByType<Entity, number>,
        where?: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<number | null> {
        return this.callAggregateFun(entityClass, "MAX", columnName, where)
    }

    private async callAggregateFun<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        fnName: "SUM" | "AVG" | "MIN" | "MAX",
        columnName: PickKeysByType<Entity, number>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[] = {},
    ): Promise<number | null> {
        const metadata = this.connection.getMetadata(entityClass)
        const result = await this.createQueryBuilder(entityClass, metadata.name)
            .setFindOptions({ where })
            .select(
                `${fnName}(${this.connection.driver.escape(
                    String(columnName),
                )})`,
                fnName,
            )
            .getRawOne()
        return result[fnName] === null ? null : parseFloat(result[fnName])
    }

    /**
     * Finds entities that match given find options.
     */
    async find<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options?: FindManyOptions<Entity>,
    ): Promise<Entity[]> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder<Entity>(
            entityClass as any,
            FindOptionsUtils.extractFindManyOptionsAlias(options) ||
                metadata.name,
        )
            .setFindOptions(options || {})
            .getMany()
    }

    /**
     * Finds entities that match given find options.
     */
    async findBy<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<Entity[]> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder<Entity>(
            entityClass as any,
            metadata.name,
        )
            .setFindOptions({ where: where })
            .getMany()
    }

    /**
     * Finds entities that match given find options.
     * Also counts all entities that match given conditions,
     * but ignores pagination settings (from and take options).
     */
    findAndCount<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options?: FindManyOptions<Entity>,
    ): Promise<[Entity[], number]> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder<Entity>(
            entityClass as any,
            FindOptionsUtils.extractFindManyOptionsAlias(options) ||
                metadata.name,
        )
            .setFindOptions(options || {})
            .getManyAndCount()
    }

    /**
     * Finds entities that match given WHERE conditions.
     * Also counts all entities that match given conditions,
     * but ignores pagination settings (from and take options).
     */
    findAndCountBy<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<[Entity[], number]> {
        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder<Entity>(
            entityClass as any,
            metadata.name,
        )
            .setFindOptions({ where })
            .getManyAndCount()
    }

    /**
     * Finds entities with ids.
     * Optionally find options or conditions can be applied.
     *
     * @deprecated use `findBy` method instead in conjunction with `In` operator, for example:
     *
     * .findBy({
     *     id: In([1, 2, 3])
     * })
     */
    async findByIds<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        ids: any[],
    ): Promise<Entity[]> {
        // if no ids passed, no need to execute a query - just return an empty array of values
        if (!ids.length) return Promise.resolve([])

        const metadata = this.connection.getMetadata(entityClass)
        return this.createQueryBuilder<Entity>(
            entityClass as any,
            metadata.name,
        )
            .andWhereInIds(ids)
            .getMany()
    }

    /**
     * Finds first entity by a given find options.
     * If entity was not found in the database - returns null.
     */
    async findOne<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options: FindOneOptions<Entity>,
    ): Promise<Entity | null> {
        const metadata = this.connection.getMetadata(entityClass)

        // prepare alias for built query
        let alias: string = metadata.name
        if (options && options.join) {
            alias = options.join.alias
        }

        if (!options.where) {
            throw new Error(
                `You must provide selection conditions in order to find a single row.`,
            )
        }

        // create query builder and apply find options
        return this.createQueryBuilder<Entity>(entityClass, alias)
            .setFindOptions({
                ...options,
                take: 1,
            })
            .getOne()
    }

    /**
     * Finds first entity that matches given where condition.
     * If entity was not found in the database - returns null.
     */
    async findOneBy<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<Entity | null> {
        const metadata = this.connection.getMetadata(entityClass)

        // create query builder and apply find options
        return this.createQueryBuilder<Entity>(entityClass, metadata.name)
            .setFindOptions({
                where,
                take: 1,
            })
            .getOne()
    }

    /**
     * Finds first entity that matches given id.
     * If entity was not found in the database - returns null.
     *
     * @deprecated use `findOneBy` method instead in conjunction with `In` operator, for example:
     *
     * .findOneBy({
     *     id: 1 // where "id" is your primary column name
     * })
     */
    async findOneById<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        id: number | string | Date | ObjectId,
    ): Promise<Entity | null> {
        const metadata = this.connection.getMetadata(entityClass)

        // create query builder and apply find options
        return this.createQueryBuilder<Entity>(entityClass, metadata.name)
            .setFindOptions({
                take: 1,
            })
            .whereInIds(metadata.ensureEntityIdMap(id))
            .getOne()
    }

    /**
     * Finds first entity by a given find options.
     * If entity was not found in the database - rejects with error.
     */
    async findOneOrFail<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        options: FindOneOptions<Entity>,
    ): Promise<Entity> {
        return this.findOne<Entity>(entityClass as any, options).then(
            (value) => {
                if (value === null) {
                    return Promise.reject(
                        new EntityNotFoundError(entityClass, options),
                    )
                }
                return Promise.resolve(value)
            },
        )
    }

    /**
     * Finds first entity that matches given where condition.
     * If entity was not found in the database - rejects with error.
     */
    async findOneByOrFail<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        where: FindOptionsWhere<Entity> | FindOptionsWhere<Entity>[],
    ): Promise<Entity> {
        return this.findOneBy<Entity>(entityClass as any, where).then(
            (value) => {
                if (value === null) {
                    return Promise.reject(
                        new EntityNotFoundError(entityClass, where),
                    )
                }
                return Promise.resolve(value)
            },
        )
    }

    /**
     * Clears all the data from the given table (truncates/drops it).
     *
     * Note: this method uses TRUNCATE and may not work as you expect in transactions on some platforms.
     * @see https://stackoverflow.com/a/5972738/925151
     */
    async clear<Entity>(entityClass: EntityTarget<Entity>): Promise<void> {
        const metadata = this.connection.getMetadata(entityClass)
        const queryRunner =
            this.queryRunner || this.connection.createQueryRunner()
        try {
            return await queryRunner.clearTable(metadata.tablePath) // await is needed here because we are using finally
        } finally {
            if (!this.queryRunner) await queryRunner.release()
        }
    }

    /**
     * Increments some column by provided value of the entities matched given conditions.
     */
    async increment<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        conditions: any,
        propertyPath: string,
        value: number | string,
    ): Promise<UpdateResult> {
        const metadata = this.connection.getMetadata(entityClass)
        const column = metadata.findColumnWithPropertyPath(propertyPath)
        if (!column)
            throw new TypeORMError(
                `Column ${propertyPath} was not found in ${metadata.targetName} entity.`,
            )

        if (isNaN(Number(value)))
            throw new TypeORMError(`Value "${value}" is not a number.`)

        // convert possible embeded path "social.likes" into object { social: { like: () => value } }
        const values: QueryDeepPartialEntity<Entity> = propertyPath
            .split(".")
            .reduceRight(
                (value, key) => ({ [key]: value } as any),
                () =>
                    this.connection.driver.escape(column.databaseName) +
                    " + " +
                    value,
            )

        return this.createQueryBuilder<Entity>(entityClass as any, "entity")
            .update(entityClass)
            .set(values)
            .where(conditions)
            .execute()
    }

    /**
     * Decrements some column by provided value of the entities matched given conditions.
     */
    async decrement<Entity extends ObjectLiteral>(
        entityClass: EntityTarget<Entity>,
        conditions: any,
        propertyPath: string,
        value: number | string,
    ): Promise<UpdateResult> {
        const metadata = this.connection.getMetadata(entityClass)
        const column = metadata.findColumnWithPropertyPath(propertyPath)
        if (!column)
            throw new TypeORMError(
                `Column ${propertyPath} was not found in ${metadata.targetName} entity.`,
            )

        if (isNaN(Number(value)))
            throw new TypeORMError(`Value "${value}" is not a number.`)

        // convert possible embeded path "social.likes" into object { social: { like: () => value } }
        const values: QueryDeepPartialEntity<Entity> = propertyPath
            .split(".")
            .reduceRight(
                (value, key) => ({ [key]: value } as any),
                () =>
                    this.connection.driver.escape(column.databaseName) +
                    " - " +
                    value,
            )

        return this.createQueryBuilder<Entity>(entityClass as any, "entity")
            .update(entityClass)
            .set(values)
            .where(conditions)
            .execute()
    }

    /**
     * Gets repository for the given entity class or name.
     * If single database connection mode is used, then repository is obtained from the
     * repository aggregator, where each repository is individually created for this entity manager.
     * When single database connection is not used, repository is being obtained from the connection.
     */
    getRepository<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
    ): Repository<Entity> {
        // find already created repository instance and return it if found
        const repoFromMap = this.repositories.get(target)
        if (repoFromMap) return repoFromMap

        // if repository was not found then create it, store its instance and return it
        if (this.connection.driver.options.type === "mongodb") {
            const newRepository = new MongoRepository(
                target,
                this,
                this.queryRunner,
            )
            this.repositories.set(target, newRepository)
            return newRepository
        } else {
            const newRepository = new Repository<any>(
                target,
                this,
                this.queryRunner,
            )
            this.repositories.set(target, newRepository)
            return newRepository
        }
    }

    /**
     * Gets tree repository for the given entity class or name.
     * If single database connection mode is used, then repository is obtained from the
     * repository aggregator, where each repository is individually created for this entity manager.
     * When single database connection is not used, repository is being obtained from the connection.
     */
    getTreeRepository<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
    ): TreeRepository<Entity> {
        // tree tables aren't supported by some drivers (mongodb)
        if (this.connection.driver.treeSupport === false)
            throw new TreeRepositoryNotSupportedError(this.connection.driver)

        // find already created repository instance and return it if found
        const repository = this.treeRepositories.find(
            (repository) => repository.target === target,
        )
        if (repository) return repository

        // check if repository is real tree repository
        const newRepository = new TreeRepository(target, this, this.queryRunner)
        this.treeRepositories.push(newRepository)
        return newRepository
    }

    /**
     * Gets mongodb repository for the given entity class.
     */
    getMongoRepository<Entity extends ObjectLiteral>(
        target: EntityTarget<Entity>,
    ): MongoRepository<Entity> {
        return this.connection.getMongoRepository<Entity>(target)
    }

    /**
     * Creates a new repository instance out of a given Repository and
     * sets current EntityManager instance to it. Used to work with custom repositories
     * in transactions.
     */
    withRepository<Entity extends ObjectLiteral, R extends Repository<any>>(
        repository: R & Repository<Entity>,
    ): R {
        const repositoryConstructor =
            repository.constructor as typeof Repository
        const { target, manager, queryRunner, ...otherRepositoryProperties } =
            repository
        return Object.assign(
            new repositoryConstructor(repository.target, this) as R,
            {
                ...otherRepositoryProperties,
            },
        )
    }

    /**
     * Gets custom entity repository marked with @EntityRepository decorator.
     *
     * @deprecated use Repository.extend to create custom repositories
     */
    getCustomRepository<T>(customRepository: ObjectType<T>): T {
        const entityRepositoryMetadataArgs =
            getMetadataArgsStorage().entityRepositories.find((repository) => {
                return (
                    repository.target ===
                    (typeof customRepository === "function"
                        ? customRepository
                        : (customRepository as any).constructor)
                )
            })
        if (!entityRepositoryMetadataArgs)
            throw new CustomRepositoryNotFoundError(customRepository)

        const entityMetadata = entityRepositoryMetadataArgs.entity
            ? this.connection.getMetadata(entityRepositoryMetadataArgs.entity)
            : undefined
        const entityRepositoryInstance =
            new (entityRepositoryMetadataArgs.target as any)(
                this,
                entityMetadata,
            )

        // NOTE: dynamic access to protected properties. We need this to prevent unwanted properties in those classes to be exposed,
        // however we need these properties for internal work of the class
        if (entityRepositoryInstance instanceof AbstractRepository) {
            if (!(entityRepositoryInstance as any)["manager"])
                (entityRepositoryInstance as any)["manager"] = this
        } else {
            if (!entityMetadata)
                throw new CustomRepositoryCannotInheritRepositoryError(
                    customRepository,
                )
            ;(entityRepositoryInstance as any)["manager"] = this
            ;(entityRepositoryInstance as any)["metadata"] = entityMetadata
        }

        return entityRepositoryInstance
    }

    /**
     * Releases all resources used by entity manager.
     * This is used when entity manager is created with a single query runner,
     * and this single query runner needs to be released after job with entity manager is done.
     */
    async release(): Promise<void> {
        if (!this.queryRunner) throw new NoNeedToReleaseEntityManagerError()

        return this.queryRunner.release()
    }
}