Files
apskel-pos-backend/internal/contract/product_contract.go
efrilmandClaude Opus 5 992bb04816 feat(order): support weight-based products
Products like fish are sold per weighing (4.2 ons, 5.6 ons), which the
order line could not represent: quantity is INTEGER and prices are always
computed as quantity * unit_price.

Model one weighing as one order line. quantity stays INTEGER and keeps
meaning "how many items"; the measured amount goes into a new nullable
order_items.weight, and the line is priced weight * unit_price. Two
weighings of the same product are two lines, never merged into one.

Keeping quantity integral avoids float comparisons in void, refund and
split bill, where accumulated rounding error would silently misbehave —
"1.4 + 1.4 + 1.4" is not 4.2 in float64, which would leave a fully paid
split-bill item marked unpaid.

BillableQuantity() is now the single place that decides between weight
and count; every price and cost calculation goes through it. Missing one
would bill a 4.2 ons fish as a single ons — wrong money, no error.

Two database constraints back the design: a weighed line always carries a
positive weight, and its quantity is pinned to 1. The latter also makes
void all-or-nothing for weighed lines, so the row-splitting branch can
never produce a zero-weight remainder row.

Also wires product.unit_id through the API, which was previously not
settable at all, and corrects the misleading comment on the request's
unit_price field — that value has never been used; price always comes
from the database.

Design notes and the audit of every price multiplication site are in
docs/rfc-weight-based-products.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-09-06 17:14:42 +07:00

122 lines
6.8 KiB
Go

package contract
import (
"time"
"github.com/google/uuid"
)
type CreateProductRequest struct {
CategoryID uuid.UUID `json:"category_id" validate:"required"`
OutletID *uuid.UUID `json:"outlet_id,omitempty"`
SKU *string `json:"sku,omitempty"`
Name string `json:"name" validate:"required,min=1,max=255"`
Description *string `json:"description,omitempty"`
Price float64 `json:"price" validate:"required,min=0"`
Cost *float64 `json:"cost,omitempty" validate:"omitempty,min=0"`
BusinessType *string `json:"business_type,omitempty"`
ImageURL *string `json:"image_url,omitempty" validate:"omitempty,max=500"`
PrinterType *string `json:"printer_type,omitempty" validate:"omitempty,max=50"`
PrintToChecker *bool `json:"print_to_checker,omitempty"`
UnitID *uuid.UUID `json:"unit_id,omitempty"`
SellBy *string `json:"sell_by,omitempty" validate:"omitempty,oneof=unit weight"`
Metadata map[string]interface{} `json:"metadata,omitempty"`
IsActive *bool `json:"is_active,omitempty"`
Variants []CreateProductVariantRequest `json:"variants,omitempty"`
InitialStock *int `json:"initial_stock,omitempty" validate:"omitempty,min=0"`
ReorderLevel *int `json:"reorder_level,omitempty" validate:"omitempty,min=0"`
CreateInventory bool `json:"create_inventory,omitempty"`
}
type UpdateProductRequest struct {
OutletID *uuid.UUID `json:"outlet_id,omitempty"`
CategoryID *uuid.UUID `json:"category_id,omitempty"`
SKU *string `json:"sku,omitempty"`
Name *string `json:"name,omitempty" validate:"omitempty,min=1,max=255"`
Description *string `json:"description,omitempty"`
Price *float64 `json:"price,omitempty" validate:"omitempty,min=0"`
Cost *float64 `json:"cost,omitempty" validate:"omitempty,min=0"`
BusinessType *string `json:"business_type,omitempty"`
ImageURL *string `json:"image_url,omitempty" validate:"omitempty,max=500"`
PrinterType *string `json:"printer_type,omitempty" validate:"omitempty,max=50"`
PrintToChecker *bool `json:"print_to_checker,omitempty"`
UnitID *uuid.UUID `json:"unit_id,omitempty"`
SellBy *string `json:"sell_by,omitempty" validate:"omitempty,oneof=unit weight"`
Metadata map[string]interface{} `json:"metadata,omitempty"`
IsActive *bool `json:"is_active,omitempty"`
ReorderLevel *int `json:"reorder_level,omitempty" validate:"omitempty,min=0"`
}
type CreateProductVariantRequest struct {
ProductID uuid.UUID `json:"product_id" validate:"required"`
Name string `json:"name" validate:"required,min=1,max=255"`
PriceModifier float64 `json:"price_modifier" validate:"required"`
Cost float64 `json:"cost" validate:"min=0"`
Metadata map[string]interface{} `json:"metadata,omitempty"`
}
type UpdateProductVariantRequest struct {
Name *string `json:"name,omitempty" validate:"omitempty,min=1,max=255"`
PriceModifier *float64 `json:"price_modifier,omitempty"`
Cost *float64 `json:"cost,omitempty" validate:"omitempty,min=0"`
Metadata map[string]interface{} `json:"metadata,omitempty"`
}
type ProductResponse struct {
ID uuid.UUID `json:"id"`
OrganizationID uuid.UUID `json:"organization_id"`
CategoryID uuid.UUID `json:"category_id"`
CategoryName string `json:"category_name"`
SKU *string `json:"sku"`
Name string `json:"name"`
Description *string `json:"description"`
Price float64 `json:"price"`
OutletPrice *float64 `json:"outlet_price,omitempty"`
OutletPrices []ProductOutletPriceResponse `json:"outlet_prices,omitempty"`
Cost float64 `json:"cost"`
BusinessType string `json:"business_type"`
ImageURL *string `json:"image_url"`
PrinterType string `json:"printer_type"`
UnitID *uuid.UUID `json:"unit_id,omitempty"`
SellBy string `json:"sell_by"`
PrintToChecker bool `json:"print_to_checker"`
Metadata map[string]interface{} `json:"metadata"`
IsActive bool `json:"is_active"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
Category *CategoryResponse `json:"category,omitempty"`
Variants []ProductVariantResponse `json:"variants,omitempty"`
}
type ProductVariantResponse struct {
ID uuid.UUID `json:"id"`
ProductID uuid.UUID `json:"product_id"`
Name string `json:"name"`
PriceModifier float64 `json:"price_modifier"`
Cost float64 `json:"cost"`
Metadata map[string]interface{} `json:"metadata"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
}
type ListProductsRequest struct {
OrganizationID *uuid.UUID `json:"organization_id,omitempty"`
OutletID *uuid.UUID `json:"outlet_id,omitempty"`
CategoryID *uuid.UUID `json:"category_id,omitempty"`
BusinessType string `json:"business_type,omitempty"`
IsActive *bool `json:"is_active,omitempty"`
Search string `json:"search,omitempty"`
MinPrice *float64 `json:"min_price,omitempty" validate:"omitempty,min=0"`
MaxPrice *float64 `json:"max_price,omitempty" validate:"omitempty,min=0"`
Page int `json:"page" validate:"required,min=1"`
Limit int `json:"limit" validate:"required,min=1,max=100"`
}
type ListProductsResponse struct {
Products []ProductResponse `json:"products"`
TotalCount int `json:"total_count"`
Page int `json:"page"`
Limit int `json:"limit"`
TotalPages int `json:"total_pages"`
}