RelationMetadata.ts

import {RelationType} from "./types/RelationTypes";
import {EntityMetadata} from "./EntityMetadata";
import {ForeignKeyMetadata} from "./ForeignKeyMetadata";
import {ObjectLiteral} from "../common/ObjectLiteral";
import {ColumnMetadata} from "./ColumnMetadata";
import {EmbeddedMetadata} from "./EmbeddedMetadata";
import {RelationMetadataArgs} from "../metadata-args/RelationMetadataArgs";
import {OnDeleteType} from "./types/OnDeleteType";
import {PropertyTypeFactory} from "./types/PropertyTypeInFunction";

/**
 * Contains all information about some entity's relation.
 */
export class RelationMetadata {

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

    /**
     * Entity metadata of the entity where this relation is placed.
     *
     * For example for @ManyToMany(type => Category) in Post, entityMetadata will be metadata of Post entity.
     */
    entityMetadata: EntityMetadata;

    /**
     * Entity metadata of the entity that is targeted by this relation.
     *
     * For example for @ManyToMany(type => Category) in Post, inverseEntityMetadata will be metadata of Category entity.
     */
    inverseEntityMetadata: EntityMetadata;

    /**
     * Entity metadata of the junction table.
     * Junction tables have their own entity metadata objects.
     * Defined only for many-to-many relations.
     */
    junctionEntityMetadata?: EntityMetadata;

    /**
     * Embedded metadata where this relation is.
     * If this relation is not in embed then this property value is undefined.
     */
    embeddedMetadata?: EmbeddedMetadata;

    /**
     * Relation type, e.g. is it one-to-one, one-to-many, many-to-one or many-to-many.
     */
    relationType: RelationType;

    /**
     * Target entity to which this relation is applied.
     * Target IS NOT equal to entityMetadata.target, because relation
     *
     * For example for @ManyToMany(type => Category) in Post, target will be Post.
     * If @ManyToMany(type => Category) is in Counters which is embedded into Post, target will be Counters.
     * If @ManyToMany(type => Category) is in abstract class BaseUser which Post extends, target will be BaseUser.
     * Target can be string if its defined in entity schema instead of class.
     */
    target: Function|string;

    /**
     * Target's property name to which relation decorator is applied.
     */
    propertyName: string;

    /**
     * Gets full path to this column property (including relation name).
     * Full path is relevant when column is used in embeds (one or multiple nested).
     * For example it will return "counters.subcounters.likes".
     * If property is not in embeds then it returns just property name of the column.
     */
    propertyPath: string;

    /**
     * Indicates if this is a parent (can be only many-to-one relation) relation in the tree tables.
     */
    isTreeParent: boolean = false;

    /**
     * Indicates if this is a children (can be only one-to-many relation) relation in the tree tables.
     */
    isTreeChildren: boolean = false;

    /**
     * Indicates if this relation's column is a primary key.
     * Can be used only for many-to-one and owner one-to-one relations.
     */
    isPrimary: boolean = false;

    /**
     * Indicates if this relation is lazily loaded.
     */
    isLazy: boolean = false;

    /**
     * Indicates if this relation is eagerly loaded.
     */
    isEager: boolean = false;

    /**
     * Indicates if persistence is enabled for the relation.
     * By default its enabled, but if you want to avoid any changes in the relation to be reflected in the database you can disable it.
     * If its disabled you can only change a relation from inverse side of a relation or using relation query builder functionality.
     * This is useful for performance optimization since its disabling avoid multiple extra queries during entity save.
     */
    persistenceEnabled: boolean = true;

    /**
     * If set to true then related objects are allowed to be inserted to the database.
     */
    isCascadeInsert: boolean = false;

    /**
     * If set to true then related objects are allowed to be updated in the database.
     */
    isCascadeUpdate: boolean = false;

    /**
     * If set to true then related objects are allowed to be remove from the database.
     */
    isCascadeRemove: boolean = false;

    /**
     * Indicates if relation column value can be nullable or not.
     */
    isNullable: boolean = true;

    /**
     * What to do with a relation on deletion of the row containing a foreign key.
     */
    onDelete?: OnDeleteType;

    /**
     * Gets the property's type to which this relation is applied.
     *
     * For example for @ManyToMany(type => Category) in Post, target will be Category.
     */
    type: Function|string;

    /**
     * Indicates if this side is an owner of this relation.
     */
    isOwning: boolean = false;

    /**
     * Checks if this relation's type is "one-to-one".
     */
    isOneToOne: boolean = false;

    /**
     * Checks if this relation is owner side of the "one-to-one" relation.
     * Owner side means this side of relation has a join column in the table.
     */
    isOneToOneOwner: boolean = false;

    /**
     * Checks if this relation has a join column (e.g. is it many-to-one or one-to-one owner side).
     */
    isWithJoinColumn: boolean = false;

    /**
     * Checks if this relation is NOT owner side of the "one-to-one" relation.
     * NOT owner side means this side of relation does not have a join column in the table.
     */
    isOneToOneNotOwner: boolean = false;

    /**
     * Checks if this relation's type is "one-to-many".
     */
    isOneToMany: boolean = false;

    /**
     * Checks if this relation's type is "many-to-one".
     */
    isManyToOne: boolean = false;

    /**
     * Checks if this relation's type is "many-to-many".
     */
    isManyToMany: boolean = false;

    /**
     * Checks if this relation's type is "many-to-many", and is owner side of the relationship.
     * Owner side means this side of relation has a join table.
     */
    isManyToManyOwner: boolean = false;

    /**
     * Checks if this relation's type is "many-to-many", and is NOT owner side of the relationship.
     * Not owner side means this side of relation does not have a join table.
     */
    isManyToManyNotOwner: boolean = false;

    /**
     * Gets the property path of the inverse side of the relation.
     */
    inverseSidePropertyPath: string;

    /**
     * Inverse side of the relation set by user.
     *
     * Inverse side set in the relation can be either string - property name of the column on inverse side,
     * either can be a function that accepts a map of properties with the object and returns one of them.
     * Second approach is used to achieve type-safety.
     */
    givenInverseSidePropertyFactory: PropertyTypeFactory<any>;

    /**
     * Gets the relation metadata of the inverse side of this relation.
     */
    inverseRelation?: RelationMetadata;

    /**
     * Join table name.
     */
    joinTableName: string;

    /**
     * Foreign keys created for this relation.
     */
    foreignKeys: ForeignKeyMetadata[] = [];

    /**
     * Join table columns.
     * Join columns can be obtained only from owner side of the relation.
     * From non-owner side of the relation join columns will be empty.
     * If this relation is a many-to-one/one-to-one then it takes join columns from the current entity.
     * If this relation is many-to-many then it takes all owner join columns from the junction entity.
     */
    joinColumns: ColumnMetadata[] = [];

    /**
     * Inverse join table columns.
     * Inverse join columns are supported only for many-to-many relations
     * and can be obtained only from owner side of the relation.
     * From non-owner side of the relation join columns will be undefined.
     */
    inverseJoinColumns: ColumnMetadata[] = [];

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

    constructor(options: {
        entityMetadata: EntityMetadata,
        embeddedMetadata?: EmbeddedMetadata,
        args: RelationMetadataArgs
    }) {
        this.entityMetadata = options.entityMetadata;
        this.embeddedMetadata = options.embeddedMetadata!;
        const args = options.args;
        this.target = args.target;
        this.propertyName = args.propertyName;
        this.relationType = args.relationType;

        if (args.inverseSideProperty)
            this.givenInverseSidePropertyFactory = args.inverseSideProperty;

        this.isLazy = args.isLazy || false;
        this.isCascadeInsert = args.options.cascade === true || (args.options.cascade instanceof Array && args.options.cascade.indexOf("insert") !== -1);
        this.isCascadeUpdate = args.options.cascade === true || (args.options.cascade instanceof Array && args.options.cascade.indexOf("update") !== -1);
        this.isCascadeRemove = args.options.cascade === true || (args.options.cascade instanceof Array && args.options.cascade.indexOf("remove") !== -1);
        this.isPrimary = args.options.primary || false;
        this.isNullable = args.options.nullable === false || this.isPrimary ? false : true;
        this.onDelete = args.options.onDelete;
        this.isEager = args.options.eager || false;
        this.persistenceEnabled = args.options.persistence === false ? false : true;
        this.isTreeParent = args.isTreeParent || false;
        this.isTreeChildren = args.isTreeChildren || false;
        this.type = args.type instanceof Function ? (args.type as () => any)() : args.type;

        this.isOneToOne = this.relationType === "one-to-one";
        this.isOneToMany = this.relationType === "one-to-many";
        this.isManyToOne = this.relationType === "many-to-one";
        this.isManyToMany = this.relationType === "many-to-many";
        this.isOneToOneNotOwner = this.isOneToOne ? true : false;
        this.isManyToManyNotOwner = this.isManyToMany ? true : false;
    }

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

    /**
     * Creates join column ids map from the given related entity ids array.
     */
    getRelationIdMap(entity: ObjectLiteral): ObjectLiteral|undefined {
        const joinColumns = this.isOwning ? this.joinColumns : this.inverseRelation!.joinColumns;
        const referencedColumns = joinColumns.map(joinColumn => joinColumn.referencedColumn!);
        // console.log("entity", entity);
        // console.log("referencedColumns", referencedColumns);
        return EntityMetadata.getValueMap(entity, referencedColumns);
    }

    /**
     * Ensures that given object is an entity id map.
     * If given id is an object then it means its already id map.
     * If given id isn't an object then it means its a value of the id column
     * and it creates a new id map with this value and name of the primary column.
     */
    ensureRelationIdMap(id: any): ObjectLiteral {
        if (id instanceof Object)
            return id;

        const joinColumns = this.isOwning ? this.joinColumns : this.inverseRelation!.joinColumns;
        const referencedColumns = joinColumns.map(joinColumn => joinColumn.referencedColumn!);

        if (referencedColumns.length > 1)
            throw new Error(`Cannot create relation id map for a single value because relation contains multiple referenced columns.`);

        return referencedColumns[0].createValueMap(id);
    }

    /**
     * Extracts column value from the given entity.
     * If column is in embedded (or recursive embedded) it extracts its value from there.
     */
    getEntityValue(entity: ObjectLiteral, getLazyRelationsPromiseValue: boolean = false): any|undefined {

        // extract column value from embeddeds of entity if column is in embedded
        if (this.embeddedMetadata) {

            // example: post[data][information][counters].id where "data", "information" and "counters" are embeddeds
            // we need to get value of "id" column from the post real entity object

            // first step - we extract all parent properties of the entity relative to this column, e.g. [data, information, counters]
            const propertyNames = [...this.embeddedMetadata.parentPropertyNames];

            // next we need to access post[data][information][counters][this.propertyName] to get column value from the counters
            // this recursive function takes array of generated property names and gets the post[data][information][counters] embed
            const extractEmbeddedColumnValue = (propertyNames: string[], value: ObjectLiteral): any => {
                const propertyName = propertyNames.shift();
                if (propertyName) {
                    if (value[propertyName]) {
                        return extractEmbeddedColumnValue(propertyNames, value[propertyName]);
                    }
                    return undefined;
                }
                return value;
            };

            // once we get nested embed object we get its column, e.g. post[data][information][counters][this.propertyName]
            const embeddedObject = extractEmbeddedColumnValue(propertyNames, entity);

            if (this.isLazy) {
                if (embeddedObject["__" + this.propertyName + "__"] !== undefined)
                    return embeddedObject["__" + this.propertyName + "__"];

                if (entity["__dirty_" + this.propertyName + "__"] || getLazyRelationsPromiseValue === true)
                    return embeddedObject[this.propertyName];

                return undefined;
            }
            return embeddedObject ? embeddedObject[this.isLazy ? "__" + this.propertyName + "__" : this.propertyName] : undefined;

        } else { // no embeds - no problems. Simply return column name by property name of the entity
            if (this.isLazy) {
                if (entity["__" + this.propertyName + "__"] !== undefined)
                    return entity["__" + this.propertyName + "__"];

                if (entity["__dirty_" + this.propertyName + "__"] || getLazyRelationsPromiseValue === true)
                    return entity[this.propertyName];

                return undefined;
            }
            return entity[this.propertyName];
        }
    }

    /**
     * Sets given entity's relation's value.
     * Using of this method helps to set entity relation's value of the lazy and non-lazy relations.
     *
     * If merge is set to true, it merges given value into currently
     */
    setEntityValue(entity: ObjectLiteral, value: any): void {
        const propertyName = (this.isLazy && !(value instanceof Promise)) ? "__" + this.propertyName + "__" : this.propertyName;

        if (this.embeddedMetadata) {

            // first step - we extract all parent properties of the entity relative to this column, e.g. [data, information, counters]
            const extractEmbeddedColumnValue = (embeddedMetadatas: EmbeddedMetadata[], map: ObjectLiteral): any => {
                // if (!object[embeddedMetadata.propertyName])
                //     object[embeddedMetadata.propertyName] = embeddedMetadata.create();

                const embeddedMetadata = embeddedMetadatas.shift();
                if (embeddedMetadata) {
                    if (!map[embeddedMetadata.propertyName])
                        map[embeddedMetadata.propertyName] = embeddedMetadata.create();

                    extractEmbeddedColumnValue(embeddedMetadatas, map[embeddedMetadata.propertyName]);
                    return map;
                }
                map[propertyName] = value;
                return map;
            };
            return extractEmbeddedColumnValue([...this.embeddedMetadata.embeddedMetadataTree], entity);

        } else {
            entity[propertyName] = value;
        }
    }

    /**
     * Creates entity id map from the given entity ids array.
     */
    createValueMap(value: any) {

        // extract column value from embeds of entity if column is in embedded
        if (this.embeddedMetadata) {

            // example: post[data][information][counters].id where "data", "information" and "counters" are embeddeds
            // we need to get value of "id" column from the post real entity object and return it in a
            // { data: { information: { counters: { id: ... } } } } format

            // first step - we extract all parent properties of the entity relative to this column, e.g. [data, information, counters]
            const propertyNames = [...this.embeddedMetadata.parentPropertyNames];

            // now need to access post[data][information][counters] to get column value from the counters
            // and on each step we need to create complex literal object, e.g. first { data },
            // then { data: { information } }, then { data: { information: { counters } } },
            // then { data: { information: { counters: [this.propertyName]: entity[data][information][counters][this.propertyName] } } }
            // this recursive function helps doing that
            const extractEmbeddedColumnValue = (propertyNames: string[], map: ObjectLiteral): any => {
                const propertyName = propertyNames.shift();
                if (propertyName) {
                    map[propertyName] = {};
                    extractEmbeddedColumnValue(propertyNames, map[propertyName]);
                    return map;
                }
                map[this.propertyName] = value;
                return map;
            };
            return extractEmbeddedColumnValue(propertyNames, {});

        } else { // no embeds - no problems. Simply return column property name and its value of the entity
            return { [this.propertyName]: value };
        }
    }

    // ---------------------------------------------------------------------
    // Builder Methods
    // ---------------------------------------------------------------------

    /**
     * Builds some depend relation metadata properties.
     * This builder method should be used only after embedded metadata tree was build.
     */
    build() {
        this.propertyPath = this.buildPropertyPath();
    }

    /**
     * Registers given foreign keys in the relation.
     * This builder method should be used to register foreign key in the relation.
     */
    registerForeignKeys(...foreignKeys: ForeignKeyMetadata[]) {
        this.foreignKeys.push(...foreignKeys);
        this.joinColumns = this.foreignKeys[0] ? this.foreignKeys[0].columns : [];
        this.inverseJoinColumns = this.foreignKeys[1] ? this.foreignKeys[1].columns : [];
        this.isOwning = this.isManyToOne || ((this.isManyToMany || this.isOneToOne) && this.joinColumns.length > 0);
        this.isOneToOneOwner = this.isOneToOne && this.isOwning;
        this.isOneToOneNotOwner = this.isOneToOne && !this.isOwning;
        this.isManyToManyOwner = this.isManyToMany && this.isOwning;
        this.isManyToManyNotOwner = this.isManyToMany && !this.isOwning;
        this.isWithJoinColumn = this.isManyToOne || this.isOneToOneOwner;
    }

    /**
     * Registers a given junction entity metadata.
     * This builder method can be called after junction entity metadata for the many-to-many relation was created.
     */
    registerJunctionEntityMetadata(junctionEntityMetadata: EntityMetadata) {
        this.junctionEntityMetadata = junctionEntityMetadata;
        this.joinTableName = junctionEntityMetadata.tableName;
        if (this.inverseRelation) {
            this.inverseRelation.junctionEntityMetadata = junctionEntityMetadata;
            this.joinTableName = junctionEntityMetadata.tableName;
        }
    }

    /**
     * Builds inverse side property path based on given inverse side property factory.
     * This builder method should be used only after properties map of the inverse entity metadata was build.
     */
    buildInverseSidePropertyPath(): string {

        if (this.givenInverseSidePropertyFactory) {
            const ownerEntityPropertiesMap = this.inverseEntityMetadata.propertiesMap;
            if (typeof this.givenInverseSidePropertyFactory === "function")
                return this.givenInverseSidePropertyFactory(ownerEntityPropertiesMap);

            if (typeof this.givenInverseSidePropertyFactory === "string")
                return this.givenInverseSidePropertyFactory;

        } else if (this.isTreeParent && this.entityMetadata.treeChildrenRelation) {
            return this.entityMetadata.treeChildrenRelation.propertyName;

        } else if (this.isTreeChildren && this.entityMetadata.treeParentRelation) {
            return this.entityMetadata.treeParentRelation.propertyName;
        }

        return "";
    }

    /**
     * Builds relation's property path based on its embedded tree.
     */
    buildPropertyPath(): string {
        if (!this.embeddedMetadata || !this.embeddedMetadata.parentPropertyNames.length)
            return this.propertyName;

        return this.embeddedMetadata.parentPropertyNames.join(".") + "." + this.propertyName;
    }

}