From 0d90703827aa18e587b7cf7c38d063bd43b98d73 Mon Sep 17 00:00:00 2001
From: Mahdi <mahdi.banilohi@gmail.com>
Date: Mon, 1 Jun 2026 13:26:25 +0330
Subject: [PATCH] update concurrentCapacity

---
 src/common/utils/booking-schedule.util.ts     | 10 +++++++---
 ...046300000-AddBusinessConcurrentCapacity.ts | 20 +++++++++++++++++++
 src/entities/business.entity.ts               |  4 ++++
 src/modules/bookings/bookings.service.ts      | 13 ++++++++++++
 .../businesses/dto/update-business.dto.ts     | 15 ++++++++++++++
 5 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 src/database/migrations/1789046300000-AddBusinessConcurrentCapacity.ts

diff --git a/src/common/utils/booking-schedule.util.ts b/src/common/utils/booking-schedule.util.ts
index 928069f..6d65ed8 100644
--- a/src/common/utils/booking-schedule.util.ts
+++ b/src/common/utils/booking-schedule.util.ts
@@ -154,6 +154,7 @@ export function generateAvailableSlotStarts(params: {
   slotStepMinutes: number;
   windows: AvailabilityWindow[];
   busy: BusyInterval[];
+  concurrentCapacity?: number;
   now?: Date;
 }): string[] {
   const {
@@ -163,9 +164,12 @@ export function generateAvailableSlotStarts(params: {
     slotStepMinutes,
     windows,
     busy,
+    concurrentCapacity = 1,
     now = new Date(),
   } = params;
 
+  const capacity = Math.max(1, concurrentCapacity);
+
   const dayAnchor = tehranDateTime(dateYmd, 12, 0);
   const dow = tehranDayOfWeek(dayAnchor);
   const dayWindows = windows.filter((w) => w.dayOfWeek === dow);
@@ -205,10 +209,10 @@ export function generateAvailableSlotStarts(params: {
         continue;
       }
 
-      const blocked = busy.some((b) =>
+      const overlapCount = busy.filter((b) =>
         intervalsOverlap(startMs, endMs, b.startMs, b.endMs),
-      );
-      if (blocked) {
+      ).length;
+      if (overlapCount >= capacity) {
         continue;
       }
 
diff --git a/src/database/migrations/1789046300000-AddBusinessConcurrentCapacity.ts b/src/database/migrations/1789046300000-AddBusinessConcurrentCapacity.ts
new file mode 100644
index 0000000..5980be7
--- /dev/null
+++ b/src/database/migrations/1789046300000-AddBusinessConcurrentCapacity.ts
@@ -0,0 +1,20 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddBusinessConcurrentCapacity1789046300000
+  implements MigrationInterface
+{
+  name = 'AddBusinessConcurrentCapacity1789046300000';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE "businesses"
+      ADD COLUMN IF NOT EXISTS "concurrentCapacity" integer NOT NULL DEFAULT 1
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE "businesses" DROP COLUMN IF EXISTS "concurrentCapacity"
+    `);
+  }
+}
diff --git a/src/entities/business.entity.ts b/src/entities/business.entity.ts
index 2cbfca6..1d12f39 100644
--- a/src/entities/business.entity.ts
+++ b/src/entities/business.entity.ts
@@ -49,6 +49,10 @@ export class BusinessEntity {
   @Column({ default: false })
   serviceClassesEnabled!: boolean;
 
+  /** Max simultaneous bookings per overlapping time window */
+  @Column({ type: 'int', default: 1 })
+  concurrentCapacity!: number;
+
   @ManyToOne(() => BusinessCategoryEntity, (category) => category.businesses, {
     onDelete: 'RESTRICT',
   })
diff --git a/src/modules/bookings/bookings.service.ts b/src/modules/bookings/bookings.service.ts
index 974d80a..d228b55 100644
--- a/src/modules/bookings/bookings.service.ts
+++ b/src/modules/bookings/bookings.service.ts
@@ -388,6 +388,7 @@ export class BookingsService {
 
     const windows = await this.loadAvailabilityWindows(businessId);
     const busy = await this.loadBusyIntervals(businessId, dateYmd);
+    const concurrentCapacity = await this.getConcurrentCapacity(businessId);
 
     const slots = generateAvailableSlotStarts({
       dateYmd,
@@ -396,11 +397,21 @@ export class BookingsService {
       slotStepMinutes: 15,
       windows,
       busy,
+      concurrentCapacity,
     });
 
     return { date: dateYmd, slots, totalDurationMinutes };
   }
 
+  private async getConcurrentCapacity(businessId: string): Promise<number> {
+    const business = await this.businessRepo.findOne({
+      where: { id: businessId },
+      select: ['id', 'concurrentCapacity'],
+    });
+    const value = business?.concurrentCapacity ?? 1;
+    return Math.max(1, value);
+  }
+
   private async loadAvailabilityWindows(
     businessId: string,
   ): Promise<AvailabilityWindow[]> {
@@ -647,6 +658,7 @@ export class BookingsService {
       );
     }
 
+    const concurrentCapacity = await this.getConcurrentCapacity(businessId);
     const slots = generateAvailableSlotStarts({
       dateYmd,
       durationMinutes,
@@ -657,6 +669,7 @@ export class BookingsService {
         excludeBookingId,
         excludeBookingGroupId,
       }),
+      concurrentCapacity,
     });
 
     const scheduledMs = scheduledAt.getTime();
diff --git a/src/modules/businesses/dto/update-business.dto.ts b/src/modules/businesses/dto/update-business.dto.ts
index 436d698..6c3f59f 100644
--- a/src/modules/businesses/dto/update-business.dto.ts
+++ b/src/modules/businesses/dto/update-business.dto.ts
@@ -1,13 +1,16 @@
 import { ApiPropertyOptional } from '@nestjs/swagger';
 import {
   IsBoolean,
+  IsInt,
   IsLatitude,
   IsLongitude,
   IsOptional,
   IsString,
   IsUUID,
   Matches,
+  Max,
   MaxLength,
+  Min,
 } from 'class-validator';
 
 export class UpdateBusinessDto {
@@ -76,4 +79,16 @@ export class UpdateBusinessDto {
   @IsOptional()
   @IsBoolean()
   serviceClassesEnabled?: boolean;
+
+  @ApiPropertyOptional({
+    example: 1,
+    description: 'How many customers can be served at the same time',
+    minimum: 1,
+    maximum: 20,
+  })
+  @IsOptional()
+  @IsInt()
+  @Min(1)
+  @Max(20)
+  concurrentCapacity?: number;
 }