feat(dashboard): add classroom utilization stats endpoint and UI

apps/server/src/dashboard/dashboard.controller.ts

@@ -48,4 +48,9 @@ export class DashboardController {
   getClassroomOccupancy() {
     return this.service.getClassroomOccupancy();
   }
+
+  @Get('classroom-utilization')
+  async getClassroomUtilization() {
+    return this.service.getClassroomUtilizationStats();
+  }
  }

apps/server/src/dashboard/dashboard.service.ts

@@ -383,4 +383,72 @@ export class DashboardService {
       occupancy: Math.min(((sMap[c.id] || 0) + (rMap[c.id] || 0) * 3) / 7, 1),
     }));
   }
+
+  async getClassroomUtilizationStats() {
+    const scopeIds = await this.scope.getScopeDepartmentIds();
+    const totalClassrooms = await this.classroomRepo.count({
+      where: await this.scope.filter({ status: Not('archived') }),
+    });
+
+    const today = new Date().toISOString().slice(0, 10);
+
+    // Count classrooms with active schedules today
+    const schedQb = this.scheduleRepo
+      .createQueryBuilder('s')
+      .select('COUNT(DISTINCT s.classroomId)', 'cnt')
+      .where('s.status = :active', { active: 'active' })
+      .andWhere('s.scheduleType = :type', { type: 'INTERNAL' })
+      .andWhere('s.startDate <= :today AND s.endDate >= :today', { today });
+    if (scopeIds) schedQb.andWhere('s.departmentId IN (:...scopeIds)', { scopeIds });
+    const schedResult = await schedQb.getRawOne();
+
+    // Count classrooms with active rentals today
+    const rentalQb = this.rentalRepo
+      .createQueryBuilder('r')
+      .select('COUNT(DISTINCT r.classroomId)', 'cnt')
+      .where('r.status != :cancelled', { cancelled: 'cancelled' })
+      .andWhere('r.startDate <= :today AND r.endDate >= :today', { today });
+    if (scopeIds) rentalQb.andWhere('r.departmentId IN (:...scopeIds)', { scopeIds });
+    const rentalResult = await rentalQb.getRawOne();
+
+    // Combine: use Set merge of both
+    const combinedQb = this.scheduleRepo
+      .createQueryBuilder('s')
+      .select('s.classroomId')
+      .where('s.status = :active', { active: 'active' })
+      .andWhere('s.scheduleType = :type', { type: 'INTERNAL' })
+      .andWhere('s.startDate <= :today AND s.endDate >= :today', { today })
+      .groupBy('s.classroomId');
+    if (scopeIds) combinedQb.andWhere('s.departmentId IN (:...scopeIds)', { scopeIds });
+    const schedIds = await combinedQb.getRawMany();
+
+    const combinedRentalQb = this.rentalRepo
+      .createQueryBuilder('r')
+      .select('r.classroomId')
+      .where('r.status != :cancelled', { cancelled: 'cancelled' })
+      .andWhere('r.startDate <= :today AND r.endDate >= :today', { today })
+      .groupBy('r.classroomId');
+    if (scopeIds) combinedRentalQb.andWhere('r.departmentId IN (:...scopeIds)', { scopeIds });
+    const rentalIds = await combinedRentalQb.getRawMany();
+
+    const allInUseIds = new Set([
+      ...schedIds.map((s) => s.classroomId),
+      ...rentalIds.map((r) => r.classroomId),
+    ]);
+
+    const scheduleCount = parseInt(schedResult?.cnt || '0', 10);
+    const rentalCount = parseInt(rentalResult?.cnt || '0', 10);
+    const inUseCount = allInUseIds.size;
+    const utilizationRate = totalClassrooms > 0
+      ? ((inUseCount / totalClassrooms) * 100).toFixed(1)
+      : '0';
+
+    return {
+      totalClassrooms,
+      inUseCount,
+      utilizationRate,
+      scheduleCount,
+      rentalCount,
+    };
+  }
  }