add diagram

Backlogs.md

@@ -410,6 +410,25 @@ CREATE TABLE IF NOT EXISTS cart (
 ]
 ```
 
+Diagram:
+```mermaid
+sequenceDiagram
+    participant Admin as Admin
+    participant BFF as BFF API (Backend-for-Frontend)
+    participant API as REST API (SpringBoot)
+    participant DB as Postgres SQL Database
+
+    Admin->>BFF: GET /carts
+    BFF->>API: GET /carts
+    API-->>DB: Query cart and cart_item tables
+    DB-->>API: Cart and Cart Item Data
+    API-->>API: Sum items price to subtotal
+    API-->>API: Compute cart grandTotal price
+    API-->>API: Build Cart Response
+    API-->>BFF: List of Carts with Cart Items
+    BFF-->>Admin: List of Carts with Cart Items
+```
+
 3. Add Product to Cart (POST /carts/{username}/items):
 
 ```sql
@@ -468,6 +487,30 @@ CREATE TABLE IF NOT EXISTS cart_item (
 }
 ```
 
+Diagram:
+```mermaid
+sequenceDiagram
+    participant App as Mobile App
+    participant BFF as BFF API (Backend-for-Frontend)
+    participant API as REST API (SpringBoot)
+    participant DB as Postgres SQL Database
+
+    App->>BFF: POST /carts/{username}/items with product sku
+    BFF->>API: GET /product/{sku}
+    API-->>BFF: Product Information
+    BFF->>API: POST /carts/{username}/items with product info
+    API-->>DB: Query cart by {username}
+    DB-->>API: Cart details
+    API-->>DB: Query cart_items by {username}
+    DB-->>API: Cart Items details
+    API-->>API: sum items price to subtotal
+    API-->>API: compute cart grandTotal price
+    API-->>API: build Cart Response
+    API-->>BFF: Cart Response details
+    BFF-->>App: Cart Response details
+```
+
+
 4. Apply Promotion Code to Specific Product in Cart (POST /carts/{username}/promotions):
 
 - Description: Applies a promotion code discount to a specific product in the user's cart.
@@ -516,7 +559,26 @@ CREATE TABLE IF NOT EXISTS cart_item (
 }
 ```
 
-
+Diagram:
+```mermaid
+sequenceDiagram
+    participant Shopper as Shopper
+    participant BFF as BFF API (Backend-for-Frontend)
+    participant API as REST API (SpringBoot)
+    participant DB as Postgres SQL Database
+
+    Shopper->>BFF: POST /carts/{username}/promotions with promotion code
+    BFF->>API: POST /carts/{username}/promotions with promotion code
+    API-->>DB: Query cart and cart items
+    DB-->>API: Cart and cart items
+    API-->>API: Apply promotion code discount to specific product in cart
+    API-->>API: Update cart with discount
+    API-->>API: Sum items price to subtotal
+    API-->>API: Compute cart grandTotal price
+    API-->>API: Build Cart Response
+    API-->>BFF: Cart with applied promotion code discount
+    BFF-->>Shopper: Cart with applied promotion code discount
+```
 
 4. Apply Promotion Code to Cart (POST /carts/{username}/promotions):
 
@@ -566,6 +628,26 @@ CREATE TABLE IF NOT EXISTS cart_item (
 }
 ```
 
+Diagram:
+```mermaid
+sequenceDiagram
+    participant Shopper as Shopper
+    participant BFF as BFF API (Backend-for-Frontend)
+    participant API as REST API (SpringBoot)
+    participant DB as Postgres SQL Database
+
+    Shopper->>BFF: POST /carts/{username}/promotions with promotion code
+    BFF->>API: POST /carts/{username}/promotions with promotion code
+    API-->>DB: Query cart table
+    DB-->>API: Cart Data
+    API-->>API: Apply promotion code discount to cart
+    API-->>API: Update cart with discount
+    API-->>API: Compute cart grandTotal price
+    API-->>API: Build Cart Response
+    API-->>BFF: Cart with applied promotion code discount
+    BFF-->>Shopper: Cart with applied promotion code discount
+```
+
 6. Paginate Products (GET /products):
 
 - Description: Retrieves a list of all products with pagination.