...

herodb/aiprompts/builderparadigm.md

@@ -0,0 +1,156 @@
+
+
+please refactor each of the objects in the the chosen folder to use builder paradigm, see below for an example
+we always start from root object, each file e.g. product.rs corresponds to a root object, the rootobject is what is stored in the DB, the rest are sub objects which are children of the root object
+
+---
+
+### ✅ Step 1: Define your struct
+```rust
+#[derive(Debug)]
+pub enum ProductType {
+    Service,
+    // Other variants...
+}
+
+#[derive(Debug)]
+pub enum ProductStatus {
+    Available,
+    Unavailable,
+    // Other variants...
+}
+
+#[derive(Debug)]
+pub struct Product {
+    id: u32,
+    name: String,
+    description: String,
+    price: f64,
+    product_type: ProductType,
+    category: String,
+    status: ProductStatus,
+    max_amount: u32,
+    validity_days: u32,
+}
+```
+
+---
+
+### ✅ Step 2: Create a builder
+
+```rust
+pub struct ProductBuilder {
+    id: Option<u32>,
+    name: Option<String>,
+    description: Option<String>,
+    price: Option<f64>,
+    product_type: Option<ProductType>,
+    category: Option<String>,
+    status: Option<ProductStatus>,
+    max_amount: Option<u32>,
+    validity_days: Option<u32>,
+}
+
+impl ProductBuilder {
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            name: None,
+            description: None,
+            price: None,
+            product_type: None,
+            category: None,
+            status: None,
+            max_amount: None,
+            validity_days: None,
+        }
+    }
+
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    pub fn name<S: Into<String>>(mut self, name: S) -> Self {
+        self.name = Some(name.into());
+        self
+    }
+
+    pub fn description<S: Into<String>>(mut self, description: S) -> Self {
+        self.description = Some(description.into());
+        self
+    }
+
+    pub fn price(mut self, price: f64) -> Self {
+        self.price = Some(price);
+        self
+    }
+
+    pub fn product_type(mut self, product_type: ProductType) -> Self {
+        self.product_type = Some(product_type);
+        self
+    }
+
+    pub fn category<S: Into<String>>(mut self, category: S) -> Self {
+        self.category = Some(category.into());
+        self
+    }
+
+    pub fn status(mut self, status: ProductStatus) -> Self {
+        self.status = Some(status);
+        self
+    }
+
+    pub fn max_amount(mut self, max_amount: u32) -> Self {
+        self.max_amount = Some(max_amount);
+        self
+    }
+
+    pub fn validity_days(mut self, validity_days: u32) -> Self {
+        self.validity_days = Some(validity_days);
+        self
+    }
+
+    pub fn build(self) -> Result<Product, &'static str> {
+        Ok(Product {
+            id: self.id.ok_or("id is required")?,
+            name: self.name.ok_or("name is required")?,
+            description: self.description.ok_or("description is required")?,
+            price: self.price.ok_or("price is required")?,
+            product_type: self.product_type.ok_or("type is required")?,
+            category: self.category.ok_or("category is required")?,
+            status: self.status.ok_or("status is required")?,
+            max_amount: self.max_amount.ok_or("max_amount is required")?,
+            validity_days: self.validity_days.ok_or("validity_days is required")?,
+        })
+    }
+}
+```
+
+---
+
+### ✅ Step 3: Use it like this
+
+```rust
+let product = ProductBuilder::new()
+    .id(1)
+    .name("Premium Service")
+    .description("Our premium service offering")
+    .price(99.99)
+    .product_type(ProductType::Service)
+    .category("Services")
+    .status(ProductStatus::Available)
+    .max_amount(100)
+    .validity_days(30)
+    .build()
+    .expect("Failed to build product");
+```
+
+---
+
+This way:
+- You don’t need to remember the order of parameters.
+- You get readable, self-documenting code.
+- It’s easier to provide defaults or optional values if you want later.
+
+Want help generating this automatically via a macro or just want it shorter? I can show you a derive macro to do that too.

herodb/aiprompts/moduledocu.md

@@ -0,0 +1,9 @@
+
+make a readme for the chosen folder (module)
+
+make a dense representation of the objects and how to use them
+explain what the rootobjects are
+
+we always start from root object, each file e.g. product.rs corresponds to a root object, the rootobject is what is stored in the DB, the rest are sub objects which are children of the root object
+
+don't explain the low level implementation details like sled, ...

herodb/src/models/biz/README.md

@@ -14,15 +14,23 @@ The business models are implemented as Rust structs and enums with serialization
 └─────────────┘     └─────────────┘     └──────┬──────┘
                           ▲                    │
                           │                    │
-                    ┌─────┴───────┐            │
+                    ┌─────┴──────────┐         │
                     │ProductComponent│         │
-                    └─────────────┘            │
+                    └────────────────┘         │
                                                ▼
                                         ┌─────────────┐
                                         │    Sale     │
                                         └─────────────┘
 ```
 
+## Root Objects
+
+- root objects are the one who are stored in the DB
+- Root Objects are
+  - currency
+  - product
+  - Sale
+
 ## Models
 
 ### Currency (Root Object)
@@ -33,8 +41,8 @@ Represents a monetary value with an amount and currency code.
 - `amount`: f64 - The monetary amount
 - `currency_code`: String - The currency code (e.g., "USD", "EUR")
 
-**Methods:**
+**Builder:**
-- `new()` - Creates a new Currency instance
+- `CurrencyBuilder` - Provides a fluent interface for creating Currency instances
 
 ### Product
 
@@ -59,8 +67,8 @@ Represents a component part of a product.
 - `created_at`: DateTime<Utc> - Creation timestamp
 - `updated_at`: DateTime<Utc> - Last update timestamp
 
-**Methods:**
+**Builder:**
-- `new()` - Creates a new ProductComponent with default timestamps
+- `ProductComponentBuilder` - Provides a fluent interface for creating ProductComponent instances
 
 #### Product  (Root Object)
 Represents a product or service offered.
@@ -81,13 +89,15 @@ Represents a product or service offered.
 - `components`: Vec<ProductComponent> - List of product components
 
 **Methods:**
-- `new()` - Creates a new Product with default timestamps
 - `add_component()` - Adds a component to this product
 - `set_purchase_period()` - Updates purchase availability timeframe
 - `set_active_period()` - Updates active timeframe
 - `is_purchasable()` - Checks if product is available for purchase
 - `is_active()` - Checks if product is still active
 
+**Builder:**
+- `ProductBuilder` - Provides a fluent interface for creating Product instances
+
 **Database Implementation:**
 - Implements `Storable` trait for serialization
 - Implements `SledModel` trait with:
@@ -115,8 +125,8 @@ Represents an item within a sale.
 - `subtotal`: Currency - Total price for this item (calculated)
 - `active_till`: DateTime<Utc> - When item/service expires
 
-**Methods:**
+**Builder:**
-- `new()` - Creates a new SaleItem with calculated subtotal
+- `SaleItemBuilder` - Provides a fluent interface for creating SaleItem instances
 
 #### Sale (Root Object)
 Represents a complete sale transaction.
@@ -134,10 +144,12 @@ Represents a complete sale transaction.
 - `items`: Vec<SaleItem> - List of items in the sale
 
 **Methods:**
-- `new()` - Creates a new Sale with default timestamps
 - `add_item()` - Adds an item to the sale and updates total
 - `update_status()` - Updates the status of the sale
 
+**Builder:**
+- `SaleBuilder` - Provides a fluent interface for creating Sale instances
+
 **Database Implementation:**
 - Implements `Storable` trait for serialization
 - Implements `SledModel` trait with:
@@ -146,62 +158,94 @@ Represents a complete sale transaction.
 
 ## Usage Examples
 
+### Creating a Currency
+
+```rust
+let price = CurrencyBuilder::new()
+    .amount(29.99)
+    .currency_code("USD")
+    .build()
+    .expect("Failed to build currency");
+```
+
 ### Creating a Product
 
 ```rust
-// Create a currency
+// Create a currency using the builder
-let price = Currency::new(29.99, "USD".to_string());
+let price = CurrencyBuilder::new()
+    .amount(29.99)
+    .currency_code("USD")
+    .build()
+    .expect("Failed to build currency");
 
-// Create a product
+// Create a component using the builder
-let mut product = Product::new(
+let component = ProductComponentBuilder::new()
-    1,                        // id
+    .id(1)
-    "Premium Service".to_string(),  // name
+    .name("Basic Support")
-    "Our premium service offering".to_string(),  // description
+    .description("24/7 email support")
-    price,                    // price
+    .quantity(1)
-    ProductType::Service,     // type
+    .build()
-    "Services".to_string(),   // category
+    .expect("Failed to build product component");
-    ProductStatus::Available, // status
-    100,                      // max_amount
-    30,                       // validity_days (service valid for 30 days)
-);
 
-// Add a component
+// Create a product using the builder
-let component = ProductComponent::new(
+let product = ProductBuilder::new()
-    1,                          // id
+    .id(1)
-    "Basic Support".to_string(),      // name
+    .name("Premium Service")
-    "24/7 email support".to_string(), // description
+    .description("Our premium service offering")
-    1,                          // quantity
+    .price(price)
-);
+    .type_(ProductType::Service)
-product.add_component(component);
+    .category("Services")
+    .status(ProductStatus::Available)
+    .max_amount(100)
+    .validity_days(30)
+    .add_component(component)
+    .build()
+    .expect("Failed to build product");
 ```
 
 ### Creating a Sale
 
 ```rust
-// Create a new sale
-let mut sale = Sale::new(
-    1,                           // id
-    101,                         // company_id
-    "John Doe".to_string(),      // buyer_name
-    "john.doe@example.com".to_string(),  // buyer_email
-    "USD".to_string(),           // currency_code
-    SaleStatus::Pending,         // status
-);
-
-// Create a sale item
 let now = Utc::now();
-let item = SaleItem::new(
-    1,                           // id
-    1,                           // sale_id
-    1,                           // product_id
-    "Premium Service".to_string(),     // name
-    1,                           // quantity
-    Currency::new(29.99, "USD".to_string()),  // unit_price
-    now + Duration::days(30),    // active_till
-);
 
-// Add the item to the sale
+// Create a currency using the builder
-sale.add_item(item);
+let unit_price = CurrencyBuilder::new()
+    .amount(29.99)
+    .currency_code("USD")
+    .build()
+    .expect("Failed to build currency");
 
-// Complete the sale
+// Create a sale item using the builder
-sale.update_status(SaleStatus::Completed);
+let item = SaleItemBuilder::new()
+    .id(1)
+    .sale_id(1)
+    .product_id(1)
+    .name("Premium Service")
+    .quantity(1)
+    .unit_price(unit_price)
+    .active_till(now + Duration::days(30))
+    .build()
+    .expect("Failed to build sale item");
+
+// Create a sale using the builder
+let mut sale = SaleBuilder::new()
+    .id(1)
+    .company_id(101)
+    .buyer_name("John Doe")
+    .buyer_email("john.doe@example.com")
+    .currency_code("USD")
+    .status(SaleStatus::Pending)
+    .add_item(item)
+    .build()
+    .expect("Failed to build sale");
+
+// Update the sale status
+sale.update_status(SaleStatus::Completed);
+```
+
+## Benefits of the Builder Pattern
+
+- You don't need to remember the order of parameters.
+- You get readable, self-documenting code.
+- It's easier to provide defaults or optional values.
+- Validation happens at build time, ensuring all required fields are provided.

herodb/src/models/biz/currency.rs

@@ -18,3 +18,39 @@ impl Currency {
         }
     }
 }
+
+/// Builder for Currency
+pub struct CurrencyBuilder {
+    amount: Option<f64>,
+    currency_code: Option<String>,
+}
+
+impl CurrencyBuilder {
+    /// Create a new CurrencyBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            amount: None,
+            currency_code: None,
+        }
+    }
+
+    /// Set the amount
+    pub fn amount(mut self, amount: f64) -> Self {
+        self.amount = Some(amount);
+        self
+    }
+
+    /// Set the currency code
+    pub fn currency_code<S: Into<String>>(mut self, currency_code: S) -> Self {
+        self.currency_code = Some(currency_code.into());
+        self
+    }
+
+    /// Build the Currency object
+    pub fn build(self) -> Result<Currency, &'static str> {
+        Ok(Currency {
+            amount: self.amount.ok_or("amount is required")?,
+            currency_code: self.currency_code.ok_or("currency_code is required")?,
+        })
+    }
+}

herodb/src/models/biz/lib.rs

@@ -13,10 +13,18 @@ pub use user::User;
 pub use vote::{Vote, VoteOption, Ballot, VoteStatus};
 pub use company::{Company, CompanyStatus, BusinessType};
 pub use meeting::Meeting;
-pub use product::{Product, Currency, ProductComponent, ProductType, ProductStatus};
+pub use product::{Product, ProductComponent, ProductType, ProductStatus};
 pub use sale::Sale;
 pub use shareholder::Shareholder;
 
+// Re-export builder types
+pub use product::{ProductBuilder, ProductComponentBuilder};
+pub use sale::{SaleBuilder, SaleItemBuilder};
+
+// Re-export Currency and its builder
+pub use product::Currency;
+pub use currency::CurrencyBuilder;
+
 // Re-export database components
 // Re-export from core module
 pub use crate::core::{SledDB, SledDBError, SledDBResult, Storable, SledModel, DB};

herodb/src/models/biz/product.rs

@@ -43,6 +43,79 @@ impl ProductComponent {
     }
 }
 
+/// Builder for ProductComponent
+pub struct ProductComponentBuilder {
+    id: Option<u32>,
+    name: Option<String>,
+    description: Option<String>,
+    quantity: Option<i32>,
+    created_at: Option<DateTime<Utc>>,
+    updated_at: Option<DateTime<Utc>>,
+}
+
+impl ProductComponentBuilder {
+    /// Create a new ProductComponentBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            name: None,
+            description: None,
+            quantity: None,
+            created_at: None,
+            updated_at: None,
+        }
+    }
+
+    /// Set the id
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    /// Set the name
+    pub fn name<S: Into<String>>(mut self, name: S) -> Self {
+        self.name = Some(name.into());
+        self
+    }
+
+    /// Set the description
+    pub fn description<S: Into<String>>(mut self, description: S) -> Self {
+        self.description = Some(description.into());
+        self
+    }
+
+    /// Set the quantity
+    pub fn quantity(mut self, quantity: i32) -> Self {
+        self.quantity = Some(quantity);
+        self
+    }
+
+    /// Set the created_at timestamp
+    pub fn created_at(mut self, created_at: DateTime<Utc>) -> Self {
+        self.created_at = Some(created_at);
+        self
+    }
+
+    /// Set the updated_at timestamp
+    pub fn updated_at(mut self, updated_at: DateTime<Utc>) -> Self {
+        self.updated_at = Some(updated_at);
+        self
+    }
+
+    /// Build the ProductComponent object
+    pub fn build(self) -> Result<ProductComponent, &'static str> {
+        let now = Utc::now();
+        Ok(ProductComponent {
+            id: self.id.ok_or("id is required")?,
+            name: self.name.ok_or("name is required")?,
+            description: self.description.ok_or("description is required")?,
+            quantity: self.quantity.ok_or("quantity is required")?,
+            created_at: self.created_at.unwrap_or(now),
+            updated_at: self.updated_at.unwrap_or(now),
+        })
+    }
+}
+
 /// Product represents a product or service offered by the Freezone
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Product {
@@ -124,6 +197,149 @@ impl Product {
     }
 }
 
+/// Builder for Product
+pub struct ProductBuilder {
+    id: Option<u32>,
+    name: Option<String>,
+    description: Option<String>,
+    price: Option<Currency>,
+    type_: Option<ProductType>,
+    category: Option<String>,
+    status: Option<ProductStatus>,
+    created_at: Option<DateTime<Utc>>,
+    updated_at: Option<DateTime<Utc>>,
+    max_amount: Option<u16>,
+    purchase_till: Option<DateTime<Utc>>,
+    active_till: Option<DateTime<Utc>>,
+    components: Vec<ProductComponent>,
+    validity_days: Option<i64>,
+}
+
+impl ProductBuilder {
+    /// Create a new ProductBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            name: None,
+            description: None,
+            price: None,
+            type_: None,
+            category: None,
+            status: None,
+            created_at: None,
+            updated_at: None,
+            max_amount: None,
+            purchase_till: None,
+            active_till: None,
+            components: Vec::new(),
+            validity_days: None,
+        }
+    }
+
+    /// Set the id
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    /// Set the name
+    pub fn name<S: Into<String>>(mut self, name: S) -> Self {
+        self.name = Some(name.into());
+        self
+    }
+
+    /// Set the description
+    pub fn description<S: Into<String>>(mut self, description: S) -> Self {
+        self.description = Some(description.into());
+        self
+    }
+
+    /// Set the price
+    pub fn price(mut self, price: Currency) -> Self {
+        self.price = Some(price);
+        self
+    }
+
+    /// Set the product type
+    pub fn type_(mut self, type_: ProductType) -> Self {
+        self.type_ = Some(type_);
+        self
+    }
+
+    /// Set the category
+    pub fn category<S: Into<String>>(mut self, category: S) -> Self {
+        self.category = Some(category.into());
+        self
+    }
+
+    /// Set the status
+    pub fn status(mut self, status: ProductStatus) -> Self {
+        self.status = Some(status);
+        self
+    }
+
+    /// Set the max amount
+    pub fn max_amount(mut self, max_amount: u16) -> Self {
+        self.max_amount = Some(max_amount);
+        self
+    }
+
+    /// Set the validity days
+    pub fn validity_days(mut self, validity_days: i64) -> Self {
+        self.validity_days = Some(validity_days);
+        self
+    }
+
+    /// Set the purchase_till date directly
+    pub fn purchase_till(mut self, purchase_till: DateTime<Utc>) -> Self {
+        self.purchase_till = Some(purchase_till);
+        self
+    }
+
+    /// Set the active_till date directly
+    pub fn active_till(mut self, active_till: DateTime<Utc>) -> Self {
+        self.active_till = Some(active_till);
+        self
+    }
+
+    /// Add a component to the product
+    pub fn add_component(mut self, component: ProductComponent) -> Self {
+        self.components.push(component);
+        self
+    }
+
+    /// Build the Product object
+    pub fn build(self) -> Result<Product, &'static str> {
+        let now = Utc::now();
+        let created_at = self.created_at.unwrap_or(now);
+        let updated_at = self.updated_at.unwrap_or(now);
+        
+        // Calculate purchase_till and active_till based on validity_days if not set directly
+        let purchase_till = self.purchase_till.unwrap_or(now + Duration::days(365));
+        let active_till = if let Some(validity_days) = self.validity_days {
+            self.active_till.unwrap_or(now + Duration::days(validity_days))
+        } else {
+            self.active_till.ok_or("Either active_till or validity_days must be provided")?
+        };
+
+        Ok(Product {
+            id: self.id.ok_or("id is required")?,
+            name: self.name.ok_or("name is required")?,
+            description: self.description.ok_or("description is required")?,
+            price: self.price.ok_or("price is required")?,
+            type_: self.type_.ok_or("type_ is required")?,
+            category: self.category.ok_or("category is required")?,
+            status: self.status.ok_or("status is required")?,
+            created_at,
+            updated_at,
+            max_amount: self.max_amount.ok_or("max_amount is required")?,
+            purchase_till,
+            active_till,
+            components: self.components,
+        })
+    }
+}
+
 // Implement Storable trait (provides default dump/load)
 impl Storable for Product {}
 
@@ -137,3 +353,6 @@ impl SledModel for Product {
         "product"
     }
 }
+
+// Import Currency from the currency module
+use super::Currency;

herodb/src/models/biz/sale.rs

@@ -57,6 +57,100 @@ impl SaleItem {
     }
 }
 
+/// Builder for SaleItem
+pub struct SaleItemBuilder {
+    id: Option<u32>,
+    sale_id: Option<u32>,
+    product_id: Option<u32>,
+    name: Option<String>,
+    quantity: Option<i32>,
+    unit_price: Option<Currency>,
+    subtotal: Option<Currency>,
+    active_till: Option<DateTime<Utc>>,
+}
+
+impl SaleItemBuilder {
+    /// Create a new SaleItemBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            sale_id: None,
+            product_id: None,
+            name: None,
+            quantity: None,
+            unit_price: None,
+            subtotal: None,
+            active_till: None,
+        }
+    }
+
+    /// Set the id
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    /// Set the sale_id
+    pub fn sale_id(mut self, sale_id: u32) -> Self {
+        self.sale_id = Some(sale_id);
+        self
+    }
+
+    /// Set the product_id
+    pub fn product_id(mut self, product_id: u32) -> Self {
+        self.product_id = Some(product_id);
+        self
+    }
+
+    /// Set the name
+    pub fn name<S: Into<String>>(mut self, name: S) -> Self {
+        self.name = Some(name.into());
+        self
+    }
+
+    /// Set the quantity
+    pub fn quantity(mut self, quantity: i32) -> Self {
+        self.quantity = Some(quantity);
+        self
+    }
+
+    /// Set the unit_price
+    pub fn unit_price(mut self, unit_price: Currency) -> Self {
+        self.unit_price = Some(unit_price);
+        self
+    }
+
+    /// Set the active_till
+    pub fn active_till(mut self, active_till: DateTime<Utc>) -> Self {
+        self.active_till = Some(active_till);
+        self
+    }
+
+    /// Build the SaleItem object
+    pub fn build(self) -> Result<SaleItem, &'static str> {
+        let unit_price = self.unit_price.ok_or("unit_price is required")?;
+        let quantity = self.quantity.ok_or("quantity is required")?;
+        
+        // Calculate subtotal
+        let amount = unit_price.amount * quantity as f64;
+        let subtotal = Currency {
+            amount,
+            currency_code: unit_price.currency_code.clone(),
+        };
+
+        Ok(SaleItem {
+            id: self.id.ok_or("id is required")?,
+            sale_id: self.sale_id.ok_or("sale_id is required")?,
+            product_id: self.product_id.ok_or("product_id is required")?,
+            name: self.name.ok_or("name is required")?,
+            quantity,
+            unit_price,
+            subtotal,
+            active_till: self.active_till.ok_or("active_till is required")?,
+        })
+    }
+}
+
 /// Sale represents a sale of products or services
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Sale {
@@ -131,6 +225,134 @@ impl Sale {
     }
 }
 
+/// Builder for Sale
+pub struct SaleBuilder {
+    id: Option<u32>,
+    company_id: Option<u32>,
+    buyer_name: Option<String>,
+    buyer_email: Option<String>,
+    total_amount: Option<Currency>,
+    status: Option<SaleStatus>,
+    sale_date: Option<DateTime<Utc>>,
+    created_at: Option<DateTime<Utc>>,
+    updated_at: Option<DateTime<Utc>>,
+    items: Vec<SaleItem>,
+    currency_code: Option<String>,
+}
+
+impl SaleBuilder {
+    /// Create a new SaleBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            company_id: None,
+            buyer_name: None,
+            buyer_email: None,
+            total_amount: None,
+            status: None,
+            sale_date: None,
+            created_at: None,
+            updated_at: None,
+            items: Vec::new(),
+            currency_code: None,
+        }
+    }
+
+    /// Set the id
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    /// Set the company_id
+    pub fn company_id(mut self, company_id: u32) -> Self {
+        self.company_id = Some(company_id);
+        self
+    }
+
+    /// Set the buyer_name
+    pub fn buyer_name<S: Into<String>>(mut self, buyer_name: S) -> Self {
+        self.buyer_name = Some(buyer_name.into());
+        self
+    }
+
+    /// Set the buyer_email
+    pub fn buyer_email<S: Into<String>>(mut self, buyer_email: S) -> Self {
+        self.buyer_email = Some(buyer_email.into());
+        self
+    }
+
+    /// Set the currency_code
+    pub fn currency_code<S: Into<String>>(mut self, currency_code: S) -> Self {
+        self.currency_code = Some(currency_code.into());
+        self
+    }
+
+    /// Set the status
+    pub fn status(mut self, status: SaleStatus) -> Self {
+        self.status = Some(status);
+        self
+    }
+
+    /// Set the sale_date
+    pub fn sale_date(mut self, sale_date: DateTime<Utc>) -> Self {
+        self.sale_date = Some(sale_date);
+        self
+    }
+
+    /// Add an item to the sale
+    pub fn add_item(mut self, item: SaleItem) -> Self {
+        self.items.push(item);
+        self
+    }
+
+    /// Build the Sale object
+    pub fn build(self) -> Result<Sale, &'static str> {
+        let now = Utc::now();
+        let id = self.id.ok_or("id is required")?;
+        let currency_code = self.currency_code.ok_or("currency_code is required")?;
+        
+        // Initialize with empty total amount
+        let mut total_amount = Currency {
+            amount: 0.0,
+            currency_code: currency_code.clone(),
+        };
+        
+        // Calculate total amount from items
+        for item in &self.items {
+            // Make sure the item's sale_id matches this sale
+            if item.sale_id != id {
+                return Err("Item sale_id must match sale id");
+            }
+            
+            if total_amount.amount == 0.0 {
+                // First item, initialize the total amount with the same currency
+                total_amount = Currency {
+                    amount: item.subtotal.amount,
+                    currency_code: item.subtotal.currency_code.clone(),
+                };
+            } else {
+                // Add to the existing total
+                // (Assumes all items have the same currency)
+                total_amount.amount += item.subtotal.amount;
+            }
+        }
+
+        Ok(Sale {
+            id,
+            company_id: self.company_id.ok_or("company_id is required")?,
+            buyer_name: self.buyer_name.ok_or("buyer_name is required")?,
+            buyer_email: self.buyer_email.ok_or("buyer_email is required")?,
+            total_amount: self.total_amount.unwrap_or(total_amount),
+            status: self.status.ok_or("status is required")?,
+            sale_date: self.sale_date.unwrap_or(now),
+            created_at: self.created_at.unwrap_or(now),
+            updated_at: self.updated_at.unwrap_or(now),
+            items: self.items,
+        })
+    }
+}
+
 // Implement Storable trait (provides default dump/load)
 impl Storable for Sale {}