From 9e38b003f96af477ee1918dc5c36180e09d01316 Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Sat, 5 Sep 2020 14:55:19 +0200
Subject: [PATCH] Model relations:  add recursive query and recursive relation

---
 package.json            |   2 +-
 src/db/ModelQuery.ts    |  32 ++++++--
 src/db/ModelRelation.ts | 167 +++++++++++++++++-----------------------
 test/ModelQuery.test.ts |  13 +++-
 4 files changed, 107 insertions(+), 107 deletions(-)

diff --git a/package.json b/package.json
index 5223c12..8eb3efd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "wms-core",
-  "version": "0.21.12",
+  "version": "0.21.13-rc.1",
   "description": "Node web application framework and toolbelt.",
   "repository": "https://gitlab.com/ArisuOngaku/wms-core",
   "author": "Alice Gaudon <alice@gaudon.pro>",
diff --git a/src/db/ModelQuery.ts b/src/db/ModelQuery.ts
index c104f66..d02e601 100644
--- a/src/db/ModelQuery.ts
+++ b/src/db/ModelQuery.ts
@@ -2,7 +2,7 @@ import {query, QueryResult} from "./MysqlConnectionManager";
 import {Connection} from "mysql";
 import Model from "./Model";
 import Pagination from "../Pagination";
-import ModelRelation from "./ModelRelation";
+import ModelRelation, {RelationDatabaseProperties} from "./ModelRelation";
 import ModelFactory from "./ModelFactory";
 
 
@@ -40,6 +40,7 @@ export default class ModelQuery<M extends Model> implements WhereFieldConsumer<M
     private _sortDirection?: 'ASC' | 'DESC';
     private readonly relations: string[] = [];
     private _pivot?: string[];
+    private _recursiveRelation?: RelationDatabaseProperties;
 
     private constructor(type: QueryType, factory: ModelFactory<M>, fields?: (string | SelectFieldValue | UpdateFieldValue)[]) {
         this.type = type;
@@ -54,7 +55,7 @@ export default class ModelQuery<M extends Model> implements WhereFieldConsumer<M
     }
 
     public on(field1: string, field2: string, test: WhereTest = WhereTest.EQ, operator: WhereOperator = WhereOperator.AND): this {
-        this._leftJoinOn.push(new WhereFieldValue(field1, field2, true, test, operator));
+        this._leftJoinOn.push(new WhereFieldValue(field1, field2.split('.').map(v => `\`${v}\``).join('.'), true, test, operator));
         return this;
     }
 
@@ -109,6 +110,12 @@ export default class ModelQuery<M extends Model> implements WhereFieldConsumer<M
         return this;
     }
 
+    public recursive(relation: RelationDatabaseProperties): this {
+        if (this.type !== QueryType.SELECT) throw new Error('Recursive queries are only implemented with SELECT.');
+        this._recursiveRelation = relation;
+        return this;
+    }
+
     public toString(final: boolean = false): string {
         let query = '';
 
@@ -124,7 +131,7 @@ export default class ModelQuery<M extends Model> implements WhereFieldConsumer<M
 
         let join = '';
         if (this._leftJoin) {
-            join = `LEFT JOIN ${this._leftJoin} ON ${this._leftJoinOn[0]}`;
+            join = `LEFT JOIN \`${this._leftJoin}\` ON ${this._leftJoinOn[0]}`;
             for (let i = 1; i < this._leftJoinOn.length; i++) {
                 join += this._leftJoinOn[i].toString(false);
             }
@@ -148,18 +155,29 @@ export default class ModelQuery<M extends Model> implements WhereFieldConsumer<M
 
         let orderBy = '';
         if (typeof this._sortBy === 'string') {
-            orderBy = `ORDER BY ${this._sortBy} ${this._sortDirection}`;
+            orderBy = `ORDER BY \`${this._sortBy}\` ${this._sortDirection}`;
         }
 
+        const table = `\`${this.table}\``;
+
         switch (this.type) {
             case QueryType.SELECT:
-                query = `SELECT ${fields} FROM ${this.table} ${join} ${where} ${orderBy} ${limit}`;
+                if (this._recursiveRelation) {
+                    const cteFields = fields.replace(RegExp(`${table}`, 'g'), 'o');
+                    query = `WITH RECURSIVE cte AS (`
+                        + `SELECT ${fields} FROM ${table} ${where}`
+                        + ` UNION `
+                        + `SELECT ${cteFields} FROM ${table} AS o, cte AS c WHERE o.\`${this._recursiveRelation.foreignKey}\`=c.\`${this._recursiveRelation.localKey}\``
+                        + `) SELECT * FROM cte ${join} ${orderBy} ${limit}`;
+                } else {
+                    query = `SELECT ${fields} FROM ${table} ${join} ${where} ${orderBy} ${limit}`;
+                }
                 break;
             case QueryType.UPDATE:
-                query = `UPDATE ${this.table} SET ${fields} ${where} ${orderBy} ${limit}`;
+                query = `UPDATE ${table} SET ${fields} ${where} ${orderBy} ${limit}`;
                 break;
             case QueryType.DELETE:
-                query = `DELETE FROM ${this.table} ${where} ${orderBy} ${limit}`;
+                query = `DELETE FROM ${table} ${where} ${orderBy} ${limit}`;
                 break;
 
         }
diff --git a/src/db/ModelRelation.ts b/src/db/ModelRelation.ts
index ff42085..c6ea22e 100644
--- a/src/db/ModelRelation.ts
+++ b/src/db/ModelRelation.ts
@@ -5,13 +5,15 @@ import ModelFactory from "./ModelFactory";
 export default abstract class ModelRelation<S extends Model, O extends Model, R extends O | O[] | null> {
     protected readonly model: S;
     protected readonly foreignFactory: ModelFactory<O>;
+    protected readonly dbProperties: RelationDatabaseProperties;
     protected readonly queryModifiers: QueryModifier<O>[] = [];
     protected readonly filters: ModelFilter<O>[] = [];
-    protected cachedModels?: R;
+    protected cachedModels?: O[];
 
-    protected constructor(model: S, foreignFactory: ModelFactory<O>) {
+    protected constructor(model: S, foreignFactory: ModelFactory<O>, dbProperties: RelationDatabaseProperties) {
         this.model = model;
         this.foreignFactory = foreignFactory;
+        this.dbProperties = dbProperties;
     }
 
     public abstract clone(): ModelRelation<S, O, R>;
@@ -32,29 +34,53 @@ export default abstract class ModelRelation<S extends Model, O extends Model, R
         return query;
     }
 
-    public abstract getModelID(): any;
+    public getModelID(): any {
+        return this.model[this.dbProperties.localKey];
+    }
 
-    protected abstract async compute(query: ModelQuery<O>): Promise<R>;
-
-    protected abstract applyRegularConstraints(query: ModelQuery<O>): void;
+    protected applyRegularConstraints(query: ModelQuery<O>): void {
+        query.where(this.dbProperties.foreignKey, this.getModelID());
+    }
 
     public async get(): Promise<R> {
         if (this.cachedModels === undefined) {
             const query = this.makeQuery();
             this.applyRegularConstraints(query);
-            this.cachedModels = await this.compute(query);
+            this.cachedModels = await query.get();
         }
-        return this.cachedModels;
+
+        let models = this.cachedModels;
+        for (const filter of this.filters) {
+            const newModels = [];
+            for (const model of models) {
+                if (await filter(model)) {
+                    newModels.push(model);
+                }
+            }
+            models = newModels;
+        }
+        return this.collectionToOutput(models);
     }
 
     public getOrFail(): R {
         if (this.cachedModels === undefined) throw new Error('Models were not fetched');
-        return this.cachedModels;
+        return this.collectionToOutput(this.cachedModels);
     }
 
-    public abstract async eagerLoad(relations: ModelRelation<S, O, R>[]): Promise<ModelQueryResult<O>>;
+    protected abstract collectionToOutput(models: O[]): R;
 
-    public abstract async populate(models: ModelQueryResult<O>): Promise<void>;
+    public async eagerLoad(relations: ModelRelation<S, O, R>[]): Promise<ModelQueryResult<O>> {
+        const ids = relations.map(r => r.getModelID()).filter(id => id !== null && id !== undefined);
+        if (ids.length === 0) return [];
+
+        const query = this.makeQuery();
+        query.where(this.dbProperties.foreignKey, ids, WhereTest.IN);
+        return await query.get();
+    }
+
+    public async populate(models: ModelQueryResult<O>): Promise<void> {
+        this.cachedModels = models.filter(m => m[this.dbProperties.foreignKey] === this.getModelID());
+    }
 
     public async count(): Promise<number> {
         const models = await this.get();
@@ -70,52 +96,16 @@ export default abstract class ModelRelation<S extends Model, O extends Model, R
 }
 
 export class OneModelRelation<S extends Model, O extends Model> extends ModelRelation<S, O, O | null> {
-    protected readonly dbProperties: RelationDatabaseProperties;
-
-    constructor(model: S, foreignFactory: ModelFactory<O>, dbProperties: RelationDatabaseProperties) {
-        super(model, foreignFactory);
-        this.dbProperties = dbProperties;
+    public constructor(model: S, foreignFactory: ModelFactory<O>, dbProperties: RelationDatabaseProperties) {
+        super(model, foreignFactory, dbProperties);
     }
 
     public clone(): OneModelRelation<S, O> {
         return new OneModelRelation(this.model, this.foreignFactory, this.dbProperties);
     }
 
-    public getModelID() {
-        return this.model[this.dbProperties.localKey];
-    }
-
-    protected async compute(query: ModelQuery<O>): Promise<O | null> {
-        return await query.first();
-    }
-
-    protected applyRegularConstraints(query: ModelQuery<O>): void {
-        query.where(this.dbProperties.foreignKey, this.getModelID());
-    }
-
-    public async get(): Promise<O | null> {
-        const model = await super.get();
-        if (model) {
-            for (const filter of this.filters) {
-                if (!(await filter(model))) {
-                    return null;
-                }
-            }
-        }
-        return model;
-    }
-
-    public async eagerLoad(relations: ModelRelation<S, O, O | null>[]): Promise<ModelQueryResult<O>> {
-        const ids = relations.map(r => r.getModelID()).filter(id => id !== null && id !== undefined);
-        if (ids.length === 0) return [];
-
-        const query = this.makeQuery();
-        query.where(this.dbProperties.foreignKey, ids, WhereTest.IN);
-        return await query.get();
-    }
-
-    public async populate(models: ModelQueryResult<O>): Promise<void> {
-        this.cachedModels = models.filter(m => m[this.dbProperties.foreignKey] === this.getModelID())[0] || null;
+    protected collectionToOutput(models: O[]): O | null {
+        return models[0] || null;
     }
 
     public async set(model: O): Promise<void> {
@@ -128,12 +118,10 @@ export class OneModelRelation<S extends Model, O extends Model> extends ModelRel
 }
 
 export class ManyModelRelation<S extends Model, O extends Model> extends ModelRelation<S, O, O[]> {
-    protected readonly dbProperties: RelationDatabaseProperties;
     protected readonly paginatedCache: { [perPage: number]: { [pageNumber: number]: ModelQueryResult<O> } } = {};
 
     constructor(model: S, foreignFactory: ModelFactory<O>, dbProperties: RelationDatabaseProperties) {
-        super(model, foreignFactory);
-        this.dbProperties = dbProperties;
+        super(model, foreignFactory, dbProperties);
     }
 
     public clone(): ManyModelRelation<S, O> {
@@ -144,29 +132,7 @@ export class ManyModelRelation<S extends Model, O extends Model> extends ModelRe
         return new OneModelRelation<S, O>(this.model, this.foreignFactory, this.dbProperties);
     }
 
-    public getModelID(): any {
-        return this.model[this.dbProperties.localKey];
-    }
-
-    protected async compute(query: ModelQuery<O>): Promise<O[]> {
-        return await query.get();
-    }
-
-    protected applyRegularConstraints(query: ModelQuery<O>): void {
-        query.where(this.dbProperties.foreignKey, this.getModelID());
-    }
-
-    public async get(): Promise<O[]> {
-        let models = await super.get();
-        for (const filter of this.filters) {
-            const newModels = [];
-            for (const model of models) {
-                if (await filter(model)) {
-                    newModels.push(model);
-                }
-            }
-            models = newModels;
-        }
+    protected collectionToOutput(models: O[]): O[] {
         return models;
     }
 
@@ -183,19 +149,6 @@ export class ManyModelRelation<S extends Model, O extends Model> extends ModelRe
 
         return cache[page];
     }
-
-    public async eagerLoad(relations: ModelRelation<S, O, O[]>[]): Promise<ModelQueryResult<O>> {
-        const ids = relations.map(r => r.getModelID()).filter(id => id !== null && id !== undefined);
-        if (ids.length === 0) return [];
-
-        const query = this.makeQuery();
-        query.where(this.dbProperties.foreignKey, ids, WhereTest.IN);
-        return await query.get();
-    }
-
-    public async populate(models: ModelQueryResult<O>): Promise<void> {
-        this.cachedModels = models.filter(m => m[this.dbProperties.foreignKey] === this.getModelID());
-    }
 }
 
 export class ManyThroughModelRelation<S extends Model, O extends Model> extends ManyModelRelation<S, O> {
@@ -218,14 +171,6 @@ export class ManyThroughModelRelation<S extends Model, O extends Model> extends
         throw new Error('Cannot reduce many through relation to one model.');
     }
 
-    public getModelID(): any {
-        return this.model[this.dbProperties.localKey];
-    }
-
-    protected async compute(query: ModelQuery<O>): Promise<O[]> {
-        return await query.get();
-    }
-
     protected applyRegularConstraints(query: ModelQuery<O>): void {
         query.where(`pivot.${this.dbProperties.localPivotKey}`, this.getModelID());
     }
@@ -248,6 +193,32 @@ export class ManyThroughModelRelation<S extends Model, O extends Model> extends
     }
 }
 
+export class RecursiveModelRelation<M extends Model> extends ManyModelRelation<M, M> {
+    public constructor(model: M, foreignFactory: ModelFactory<M>, dbProperties: RelationDatabaseProperties) {
+        super(model, foreignFactory, dbProperties);
+        this.constraint(query => query.recursive(this.dbProperties));
+    }
+
+    public clone(): RecursiveModelRelation<M> {
+        return new RecursiveModelRelation(this.model, this.foreignFactory, this.dbProperties);
+    }
+
+    public async populate(models: ModelQueryResult<M>): Promise<void> {
+        await super.populate(models);
+        if (this.cachedModels) {
+            let count;
+            do {
+                count = this.cachedModels.length;
+                this.cachedModels.push(...models.filter(model =>
+                    !this.cachedModels!.find(cached => cached.equals(model)) &&
+                    this.cachedModels!.find(cached => cached[this.dbProperties.localKey] === model[this.dbProperties.foreignKey])
+                ));
+            } while (count !== this.cachedModels.length);
+        }
+    }
+
+}
+
 export type QueryModifier<M extends Model> = (query: ModelQuery<M>) => ModelQuery<M>;
 
 export type ModelFilter<O extends Model> = (model: O) => boolean | Promise<boolean>;
diff --git a/test/ModelQuery.test.ts b/test/ModelQuery.test.ts
index 8f0bab9..44d667d 100644
--- a/test/ModelQuery.test.ts
+++ b/test/ModelQuery.test.ts
@@ -10,7 +10,18 @@ describe('Test ModelQuery', () => {
             .groupWhere(q => q.where('f4', 'v4'), WhereOperator.OR))
             .where('f5', 'v5');
 
-        expect(query.toString(true)).toBe('SELECT * FROM model  WHERE `f1`=? AND (`f2`=? AND `f3`=? OR (`f4`=?)) AND `f5`=?  ');
+        expect(query.toString(true)).toBe('SELECT * FROM `model`  WHERE `f1`=? AND (`f2`=? AND `f3`=? OR (`f4`=?)) AND `f5`=?  ');
         expect(query.variables.length).toBe(5);
     });
+
+    test('recursive queries', () => {
+        const query = ModelQuery.select({table: 'model'} as unknown as ModelFactory<Model>, '*');
+        query.where('f1', 'v1');
+        query.leftJoin('test').on('model.j1', 'test.j2');
+        query.recursive({localKey: 'local', foreignKey: 'foreign'});
+        query.sortBy('f2', 'ASC').limit(8);
+
+        expect(query.toString(true)).toBe("WITH RECURSIVE cte AS (SELECT `model`.* FROM `model` WHERE `f1`=? UNION SELECT o.* FROM `model` AS o, cte AS c WHERE o.`foreign`=c.`local`) SELECT * FROM cte LEFT JOIN `test` ON `model`.`j1`=`test`.`j2` ORDER BY `f2` ASC LIMIT 8");
+        expect(query.variables.length).toBe(1);
+    });
 });