feat(observations): add observations.service

src/observations/observations.service.ts

@@ -0,0 +1,47 @@
+import { Injectable } from '@nestjs/common';
+import { and, desc, eq } from 'drizzle-orm';
+import { db } from '../db/client';
+import { observations } from '../db/schema';
+import { AuditService } from '../audit/audit.service';
+import type { AuthenticatedSession } from '../auth/tenant.guard';
+import type { CreateObservationDto } from './dto';
+
+@Injectable()
+export class ObservationsService {
+  constructor(private readonly audit: AuditService) {}
+
+  async list(session: AuthenticatedSession, subjectType?: string, subjectId?: string) {
+    return db.query.observations.findMany({
+      where: and(
+        eq(observations.tenantId, session.tenantId),
+        ...(subjectType ? [eq(observations.subjectType, subjectType)] : []),
+        ...(subjectId ? [eq(observations.subjectId, subjectId)] : []),
+      ),
+      orderBy: desc(observations.observedAt),
+    });
+  }
+
+  async create(session: AuthenticatedSession, dto: CreateObservationDto) {
+    const [row] = await db
+      .insert(observations)
+      .values({
+        tenantId: session.tenantId,
+        subjectType: dto.subjectType,
+        subjectId: dto.subjectId,
+        metric: dto.metric,
+        value: dto.value,
+        unit: dto.unit,
+        source: dto.source,
+        observedAt: dto.observedAt ? new Date(dto.observedAt) : new Date(),
+        confidence: dto.confidence !== undefined ? String(dto.confidence) : undefined,
+      })
+      .returning();
+    await this.audit.record(null, {
+      tenantId: session.tenantId,
+      actorId: session.userId,
+      action: 'observation.created',
+      resource: `observation:${row.id}:${dto.subjectType}/${dto.subjectId}`,
+    });
+    return row;
+  }
+}