MSA Shop

flowchart TB
    Client["Web / App"]
    Gateway["API Gateway (8080)<br/>routing / JWT / Rate Limit / Swagger"]
    subgraph Monitoring["Monitoring"]
      Prometheus["Prometheus"]
      Grafana["Grafana"]
      Zipkin["Zipkin"]
    end
    subgraph Services["Microservices"]
      User["user-service (8081)<br/>user / login / JWT"]
      Product["product-service (8082)<br/>product / stock / cache"]
      Order["order-service (8083)<br/>order / cart / SAGA / Outbox"]
      Payment["payment-service (8084)<br/>payment / cancel"]
      Settlement["settlement-service (8085)<br/>daily / monthly settlement"]
      Rabbit["RabbitMQ<br/>payment.events"]
    end
    subgraph Storage["Data Storage (independent DB per service)"]
      UserDb[("userdb")]
      ProductDb[("productdb")]
      Redis[("Redis<br/>product cache")]
      OrderDb[("orderdb")]
      PaymentDb[("paymentdb")]
      SettlementDb[("settlementdb")]
    end

    Client -->|HTTP Bearer JWT| Gateway
    Gateway -->|/users /auth| User
    Gateway -->|/products| Product
    Gateway -->|/orders /cart| Order
    Gateway -->|/settlements| Settlement
    Order -->|REST payment / cancel| Payment
    Order -->|REST stock reserve / release| Product
    Payment -->|payment.completed event| Rabbit
    Rabbit -->|subscription| Settlement
    User --> UserDb
    Product --> ProductDb
    Product --> Redis
    Order --> OrderDb
    Payment --> PaymentDb
    Settlement --> SettlementDb
    Services -. traces .-> Zipkin
    Services -. metrics .-> Prometheus
    Prometheus --> Grafana

erDiagram
    users ||--o{ cart_items : "owns"
    users ||--o{ orders : "places"
    users ||--o{ payments : "makes"
    products ||--o{ cart_items : "contains"
    products ||--o{ orders : "contains"
    orders ||--|| payments : "associated_with"

    users {
      bigint id PK
      string email UK
      string password
      string name
    }
    products {
      bigint id PK
      string name
      string category
      int price
      int stock_quantity
    }
    cart_items {
      bigint id PK
      bigint user_id FK
      bigint product_id FK
      int quantity
    }
    orders {
      bigint id PK
      bigint user_id FK
      bigint product_id FK
      int quantity
      int total_amount
      string status
      bigint payment_id
      datetime created_at
    }
    payments {
      bigint id PK
      bigint user_id FK
      int amount
      string payment_method
      string status
      datetime created_at
    }
    outbox_events {
      bigint id PK
      string event_type
      text payload
      string status
      datetime created_at
      datetime processed_at
    }
    daily_settlements {
      bigint id PK
      date report_date UK
      bigint total_amount
      int payment_count
    }
    monthly_settlements {
      bigint id PK
      string settlement_year_month UK
      bigint total_amount
      int payment_count
    }

sequenceDiagram
    actor Client
    participant Gateway
    participant OrderController
    participant OrderService
    participant ProductService
    participant ProductRepository
    participant PaymentService
    participant PaymentRepository
    participant OrderRepository

    Client->>Gateway: POST /orders (productId, quantity, paymentMethod)
    Gateway->>OrderController: X-User-Id + Request
    OrderController->>OrderService: createOrder(userId, request)
    OrderService->>ProductService: GET /products/{id} (price lookup)
    ProductService->>ProductRepository: findById
    ProductRepository-->>ProductService: Product
    ProductService-->>OrderService: Product (price)
    OrderService->>ProductService: POST /internal/stocks/reserve
    ProductService->>ProductRepository: stock lookup, decrease
    ProductRepository-->>ProductService: success
    ProductService-->>OrderService: { success: true }
    OrderService->>PaymentService: POST /payments (userId, amount, method)
    PaymentService->>PaymentRepository: save
    PaymentRepository-->>PaymentService: Payment
    PaymentService-->>OrderService: { paymentId, success: true }
    OrderService->>OrderRepository: save(order)
    OrderRepository-->>OrderService: Order
    OrderService-->>OrderController: OrderResponse
    OrderController-->>Gateway: 201
    Gateway-->>Client: OrderResponse
    Note over OrderService,ProductService: On failure: SAGA compensation / stock release / outbox recovery