# Product Migration - Database Changes Plan

## Overview

This document details the database schema changes required for Phase 1 of the Multi-Marketplace Product Architecture. It serves as the implementation guide for the Alembic migrations.

**Related Documents:**
- [Multi-Marketplace Product Architecture](./multi-marketplace-product-architecture.md) - Full architecture design
- [Marketplace Integration Architecture](../../architecture/marketplace-integration.md) - System-wide integration plan

---

## Current State Analysis

### Existing Tables

#### `marketplace_products` (Current)

| Column | Type | Constraints | Notes |
|--------|------|-------------|-------|
| id | Integer | PK, Index | |
| marketplace_product_id | String | Unique, Index, NOT NULL | Feed product ID |
| title | String | NOT NULL | Single language only |
| description | String | | Single language only |
| link | String | | |
| image_link | String | | |
| availability | String | Index | |
| price | String | | Raw price string "19.99 EUR" |
| sale_price | String | | Raw price string |
| brand | String | Index | |
| gtin | String | Index | |
| mpn | String | | |
| condition | String | | |
| adult | String | | |
| multipack | Integer | | |
| is_bundle | String | | |
| age_group | String | | |
| color | String | | |
| gender | String | | |
| material | String | | |
| pattern | String | | |
| size | String | | |
| size_type | String | | |
| size_system | String | | |
| item_group_id | String | | |
| google_product_category | String | Index | |
| product_type | String | | Raw feed value |
| custom_label_0-4 | String | | |
| additional_image_link | String | | Single string, not array |
| unit_pricing_measure | String | | |
| unit_pricing_base_measure | String | | |
| identifier_exists | String | | |
| shipping | String | | |
| currency | String | | |
| marketplace | String | Index, Default='Letzshop' | |
| vendor_name | String | Index | |
| created_at | DateTime | | TimestampMixin |
| updated_at | DateTime | | TimestampMixin |

**Indexes:**
- `idx_marketplace_vendor` (marketplace, vendor_name)
- `idx_marketplace_brand` (marketplace, brand)

#### `products` (Current)

| Column | Type | Constraints | Notes |
|--------|------|-------------|-------|
| id | Integer | PK, Index | |
| vendor_id | Integer | FK → vendors.id, NOT NULL | |
| marketplace_product_id | Integer | FK → marketplace_products.id, NOT NULL | |
| product_id | String | | Vendor's internal SKU |
| price | Float | | Override |
| sale_price | Float | | Override |
| currency | String | | Override |
| availability | String | | Override |
| condition | String | | Override |
| is_featured | Boolean | Default=False | |
| is_active | Boolean | Default=True | |
| display_order | Integer | Default=0 | |
| min_quantity | Integer | Default=1 | |
| max_quantity | Integer | | |
| created_at | DateTime | | TimestampMixin |
| updated_at | DateTime | | TimestampMixin |

**Constraints:**
- `uq_product` UNIQUE (vendor_id, marketplace_product_id)

**Indexes:**
- `idx_product_active` (vendor_id, is_active)
- `idx_product_featured` (vendor_id, is_featured)

### Issues with Current Schema

| Issue | Impact | Solution |
|-------|--------|----------|
| No translation support | Cannot support multi-language feeds | Add translation tables |
| No product type distinction | Cannot differentiate physical/digital | Add product_type enum |
| No digital product fields | Cannot support game keys, downloads | Add digital-specific columns |
| Price as String | Harder to filter/sort by price | Add parsed numeric price |
| Single additional_image_link | Can't store multiple images properly | Add JSON array column |
| No override pattern properties | No `effective_*` helpers | Add to model layer |
| One-to-one relationship | Same product can't exist for multiple vendors | Fix to one-to-many |

---

## Target Schema

### Visual Diagram

```
┌─────────────────────────────────┐
│      marketplace_products       │
├─────────────────────────────────┤
│ id (PK)                         │
│ marketplace_product_id (UNIQUE) │
│ marketplace                     │
│ vendor_name                     │
│                                 │
│ # Product Type (NEW)            │
│ product_type (ENUM)             │
│ is_digital                      │
│ digital_delivery_method (ENUM)  │
│ platform                        │
│ region_restrictions (JSON)      │
│ license_type                    │
│                                 │
│ # Pricing (ENHANCED)            │
│ price (String) [raw]            │
│ price_numeric (Float) [NEW]     │
│ sale_price (String) [raw]       │
│ sale_price_numeric (Float) [NEW]│
│ currency                        │
│                                 │
│ # Media (ENHANCED)              │
│ image_link                      │
│ additional_image_link [legacy]  │
│ additional_images (JSON) [NEW]  │
│                                 │
│ # Attributes (NEW)              │
│ attributes (JSON)               │
│                                 │
│ # Status (NEW)                  │
│ is_active                       │
│                                 │
│ # Renamed                       │
│ product_type_raw [was product_type] │
│                                 │
│ # Preserved Google Shopping     │
│ brand, gtin, mpn, condition...  │
│ google_product_category...      │
│ custom_label_0-4...             │
└─────────────────────────────────┘
           │
           │ 1:N
           ▼
┌─────────────────────────────────┐
│ marketplace_product_translations │
├─────────────────────────────────┤
│ id (PK)                         │
│ marketplace_product_id (FK)     │
│ language ('en','fr','de','lb')  │
│                                 │
│ # Localized Content             │
│ title (NOT NULL)                │
│ description                     │
│ short_description               │
│                                 │
│ # SEO                           │
│ meta_title                      │
│ meta_description                │
│ url_slug                        │
│                                 │
│ # Source Tracking               │
│ source_import_id                │
│ source_file                     │
│                                 │
│ created_at, updated_at          │
├─────────────────────────────────┤
│ UNIQUE(marketplace_product_id,  │
│        language)                │
└─────────────────────────────────┘

┌─────────────────────────────────┐
│           products              │
├─────────────────────────────────┤
│ id (PK)                         │
│ vendor_id (FK)                  │
│ marketplace_product_id (FK)     │
│                                 │
│ # Renamed                       │
│ vendor_sku [was product_id]     │
│                                 │
│ # Existing Overrides            │
│ price                           │
│ sale_price                      │
│ currency                        │
│ availability                    │
│ condition                       │
│                                 │
│ # New Overrides                 │
│ brand (NEW)                     │
│ primary_image_url (NEW)         │
│ additional_images (JSON) (NEW)  │
│ download_url (NEW)              │
│ license_type (NEW)              │
│ fulfillment_email_template (NEW)│
│                                 │
│ # Vendor-Specific               │
│ is_featured                     │
│ is_active                       │
│ display_order                   │
│ min_quantity                    │
│ max_quantity                    │
│                                 │
│ created_at, updated_at          │
├─────────────────────────────────┤
│ UNIQUE(vendor_id,               │
│        marketplace_product_id)  │
└─────────────────────────────────┘
           │
           │ 1:N
           ▼
┌─────────────────────────────────┐
│      product_translations       │
├─────────────────────────────────┤
│ id (PK)                         │
│ product_id (FK)                 │
│ language                        │
│                                 │
│ # Overridable (NULL = inherit)  │
│ title                           │
│ description                     │
│ short_description               │
│ meta_title                      │
│ meta_description                │
│ url_slug                        │
│                                 │
│ created_at, updated_at          │
├─────────────────────────────────┤
│ UNIQUE(product_id, language)    │
└─────────────────────────────────┘
```

---

## Migration Plan

### Migration 1: Add Product Type and Digital Fields

**File:** `alembic/versions/xxxx_add_product_type_digital_fields.py`

**Changes:**

```sql
-- Create ENUMs
CREATE TYPE product_type_enum AS ENUM ('physical', 'digital', 'service', 'subscription');
CREATE TYPE digital_delivery_enum AS ENUM ('download', 'email', 'in_app', 'streaming', 'license_key');

-- Add columns to marketplace_products
ALTER TABLE marketplace_products ADD COLUMN product_type product_type_enum NOT NULL DEFAULT 'physical';
ALTER TABLE marketplace_products ADD COLUMN is_digital BOOLEAN NOT NULL DEFAULT false;
ALTER TABLE marketplace_products ADD COLUMN digital_delivery_method digital_delivery_enum;
ALTER TABLE marketplace_products ADD COLUMN platform VARCHAR;
ALTER TABLE marketplace_products ADD COLUMN region_restrictions JSON;
ALTER TABLE marketplace_products ADD COLUMN license_type VARCHAR;
ALTER TABLE marketplace_products ADD COLUMN source_url VARCHAR;
ALTER TABLE marketplace_products ADD COLUMN attributes JSON;
ALTER TABLE marketplace_products ADD COLUMN additional_images JSON;
ALTER TABLE marketplace_products ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT true;
ALTER TABLE marketplace_products ADD COLUMN price_numeric FLOAT;
ALTER TABLE marketplace_products ADD COLUMN sale_price_numeric FLOAT;

-- Rename product_type to product_type_raw (keep original feed value)
ALTER TABLE marketplace_products RENAME COLUMN product_type TO product_type_raw;

-- Add index
CREATE INDEX idx_mp_product_type ON marketplace_products (product_type, is_digital);
```

**Rollback:**

```sql
DROP INDEX idx_mp_product_type;
ALTER TABLE marketplace_products RENAME COLUMN product_type_raw TO product_type;
ALTER TABLE marketplace_products DROP COLUMN sale_price_numeric;
ALTER TABLE marketplace_products DROP COLUMN price_numeric;
ALTER TABLE marketplace_products DROP COLUMN is_active;
ALTER TABLE marketplace_products DROP COLUMN additional_images;
ALTER TABLE marketplace_products DROP COLUMN attributes;
ALTER TABLE marketplace_products DROP COLUMN source_url;
ALTER TABLE marketplace_products DROP COLUMN license_type;
ALTER TABLE marketplace_products DROP COLUMN region_restrictions;
ALTER TABLE marketplace_products DROP COLUMN platform;
ALTER TABLE marketplace_products DROP COLUMN digital_delivery_method;
ALTER TABLE marketplace_products DROP COLUMN is_digital;
ALTER TABLE marketplace_products DROP COLUMN product_type;
DROP TYPE digital_delivery_enum;
DROP TYPE product_type_enum;
```

---

### Migration 2: Create Translation Tables

**File:** `alembic/versions/xxxx_create_translation_tables.py`

**Changes:**

```sql
-- Create marketplace_product_translations
CREATE TABLE marketplace_product_translations (
    id SERIAL PRIMARY KEY,
    marketplace_product_id INTEGER NOT NULL REFERENCES marketplace_products(id) ON DELETE CASCADE,
    language VARCHAR(5) NOT NULL,
    title VARCHAR NOT NULL,
    description TEXT,
    short_description VARCHAR(500),
    meta_title VARCHAR(70),
    meta_description VARCHAR(160),
    url_slug VARCHAR(255),
    source_import_id INTEGER,
    source_file VARCHAR,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT uq_marketplace_product_translation UNIQUE (marketplace_product_id, language)
);

CREATE INDEX idx_mpt_language ON marketplace_product_translations (language);
CREATE INDEX idx_mpt_mp_id ON marketplace_product_translations (marketplace_product_id);

-- Create product_translations
CREATE TABLE product_translations (
    id SERIAL PRIMARY KEY,
    product_id INTEGER NOT NULL REFERENCES products(id) ON DELETE CASCADE,
    language VARCHAR(5) NOT NULL,
    title VARCHAR,
    description TEXT,
    short_description VARCHAR(500),
    meta_title VARCHAR(70),
    meta_description VARCHAR(160),
    url_slug VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT uq_product_translation UNIQUE (product_id, language)
);

CREATE INDEX idx_pt_product_language ON product_translations (product_id, language);
```

**Rollback:**

```sql
DROP TABLE product_translations;
DROP TABLE marketplace_product_translations;
```

---

### Migration 3: Add Override Fields to Products

**File:** `alembic/versions/xxxx_add_product_override_fields.py`

**Changes:**

```sql
-- Rename product_id to vendor_sku
ALTER TABLE products RENAME COLUMN product_id TO vendor_sku;

-- Add new override columns
ALTER TABLE products ADD COLUMN brand VARCHAR;
ALTER TABLE products ADD COLUMN primary_image_url VARCHAR;
ALTER TABLE products ADD COLUMN additional_images JSON;
ALTER TABLE products ADD COLUMN download_url VARCHAR;
ALTER TABLE products ADD COLUMN license_type VARCHAR;
ALTER TABLE products ADD COLUMN fulfillment_email_template VARCHAR;

-- Add index for vendor_sku
CREATE INDEX idx_product_vendor_sku ON products (vendor_id, vendor_sku);
```

**Rollback:**

```sql
DROP INDEX idx_product_vendor_sku;
ALTER TABLE products DROP COLUMN fulfillment_email_template;
ALTER TABLE products DROP COLUMN license_type;
ALTER TABLE products DROP COLUMN download_url;
ALTER TABLE products DROP COLUMN additional_images;
ALTER TABLE products DROP COLUMN primary_image_url;
ALTER TABLE products DROP COLUMN brand;
ALTER TABLE products RENAME COLUMN vendor_sku TO product_id;
```

---

### Migration 4: Data Migration

**File:** `alembic/versions/xxxx_migrate_product_data.py`

**Changes:**

```sql
-- Migrate existing title/description to translations table (default language: 'en')
INSERT INTO marketplace_product_translations (
    marketplace_product_id,
    language,
    title,
    description,
    created_at,
    updated_at
)
SELECT
    id,
    'en',
    title,
    description,
    created_at,
    updated_at
FROM marketplace_products
WHERE title IS NOT NULL
ON CONFLICT (marketplace_product_id, language) DO NOTHING;

-- Parse prices to numeric (handled in Python for complex parsing)
-- This will be done via a Python data migration function
```

**Python Migration Function:**

```python
def parse_and_update_prices(connection):
    """Parse price strings to numeric values."""
    import re

    # Get all marketplace products
    result = connection.execute(
        text("SELECT id, price, sale_price FROM marketplace_products")
    )

    for row in result:
        price_numeric = parse_price(row.price)
        sale_price_numeric = parse_price(row.sale_price)

        connection.execute(
            text("""
                UPDATE marketplace_products
                SET price_numeric = :price, sale_price_numeric = :sale_price
                WHERE id = :id
            """),
            {"id": row.id, "price": price_numeric, "sale_price": sale_price_numeric}
        )

def parse_price(price_str: str) -> float | None:
    """Parse price string like '19.99 EUR' to float."""
    if not price_str:
        return None

    # Extract numeric value
    numbers = re.findall(r'[\d.,]+', str(price_str))
    if numbers:
        num_str = numbers[0].replace(',', '.')
        try:
            return float(num_str)
        except ValueError:
            pass
    return None
```

**Rollback:**

```sql
-- Data migration is one-way, original columns preserved
-- No rollback needed for data
```

---

## Migration Execution Order

| Order | Migration | Risk Level | Notes |
|-------|-----------|------------|-------|
| 1 | Add product type & digital fields | Low | All columns nullable or have defaults |
| 2 | Create translation tables | Low | New tables, no existing data affected |
| 3 | Add product override fields | Low | All columns nullable |
| 4 | Data migration | Medium | Copies data, original preserved |

---

## Model Layer Updates Required

### MarketplaceProduct Model

```python
# Add to models/database/marketplace_product.py

class ProductType(str, Enum):
    PHYSICAL = "physical"
    DIGITAL = "digital"
    SERVICE = "service"
    SUBSCRIPTION = "subscription"

class DigitalDeliveryMethod(str, Enum):
    DOWNLOAD = "download"
    EMAIL = "email"
    IN_APP = "in_app"
    STREAMING = "streaming"
    LICENSE_KEY = "license_key"

class MarketplaceProduct(Base, TimestampMixin):
    # ... existing fields ...

    # NEW FIELDS
    product_type = Column(SQLEnum(ProductType), default=ProductType.PHYSICAL, nullable=False)
    is_digital = Column(Boolean, default=False, nullable=False)
    digital_delivery_method = Column(SQLEnum(DigitalDeliveryMethod), nullable=True)
    platform = Column(String, nullable=True)
    region_restrictions = Column(JSON, nullable=True)
    license_type = Column(String, nullable=True)
    source_url = Column(String, nullable=True)
    attributes = Column(JSON, nullable=True)
    additional_images = Column(JSON, nullable=True)
    is_active = Column(Boolean, default=True, nullable=False)
    price_numeric = Column(Float, nullable=True)
    sale_price_numeric = Column(Float, nullable=True)
    product_type_raw = Column(String)  # Renamed from product_type

    # NEW RELATIONSHIP
    translations = relationship(
        "MarketplaceProductTranslation",
        back_populates="marketplace_product",
        cascade="all, delete-orphan"
    )

    # Change to one-to-many
    vendor_products = relationship("Product", back_populates="marketplace_product")
```

### MarketplaceProductTranslation Model (NEW)

```python
# models/database/marketplace_product_translation.py

class MarketplaceProductTranslation(Base, TimestampMixin):
    __tablename__ = "marketplace_product_translations"

    id = Column(Integer, primary_key=True)
    marketplace_product_id = Column(
        Integer,
        ForeignKey("marketplace_products.id", ondelete="CASCADE"),
        nullable=False
    )
    language = Column(String(5), nullable=False)
    title = Column(String, nullable=False)
    description = Column(Text, nullable=True)
    short_description = Column(String(500), nullable=True)
    meta_title = Column(String(70), nullable=True)
    meta_description = Column(String(160), nullable=True)
    url_slug = Column(String(255), nullable=True)
    source_import_id = Column(Integer, nullable=True)
    source_file = Column(String, nullable=True)

    marketplace_product = relationship(
        "MarketplaceProduct",
        back_populates="translations"
    )

    __table_args__ = (
        UniqueConstraint("marketplace_product_id", "language", name="uq_marketplace_product_translation"),
        Index("idx_mpt_language", "language"),
    )
```

### Product Model Updates

```python
# Update models/database/product.py

class Product(Base, TimestampMixin):
    # ... existing fields ...

    # RENAMED
    vendor_sku = Column(String)  # Was: product_id

    # NEW OVERRIDE FIELDS
    brand = Column(String, nullable=True)
    primary_image_url = Column(String, nullable=True)
    additional_images = Column(JSON, nullable=True)
    download_url = Column(String, nullable=True)
    license_type = Column(String, nullable=True)
    fulfillment_email_template = Column(String, nullable=True)

    # NEW RELATIONSHIP
    translations = relationship(
        "ProductTranslation",
        back_populates="product",
        cascade="all, delete-orphan"
    )

    # OVERRIDABLE FIELDS LIST
    OVERRIDABLE_FIELDS = [
        "price", "sale_price", "currency", "brand", "condition",
        "availability", "primary_image_url", "additional_images",
        "download_url", "license_type"
    ]

    # EFFECTIVE PROPERTIES
    @property
    def effective_price(self) -> float | None:
        if self.price is not None:
            return self.price
        return self.marketplace_product.price_numeric if self.marketplace_product else None

    @property
    def effective_brand(self) -> str | None:
        if self.brand is not None:
            return self.brand
        return self.marketplace_product.brand if self.marketplace_product else None

    # ... other effective_* properties ...

    def get_override_info(self) -> dict:
        """Get all fields with inheritance flags."""
        mp = self.marketplace_product
        return {
            "price": self.effective_price,
            "price_overridden": self.price is not None,
            "price_source": mp.price_numeric if mp else None,
            # ... other fields ...
        }

    def reset_field_to_source(self, field_name: str) -> bool:
        """Reset a field to inherit from marketplace product."""
        if field_name in self.OVERRIDABLE_FIELDS:
            setattr(self, field_name, None)
            return True
        return False
```

### ProductTranslation Model (NEW)

```python
# models/database/product_translation.py

class ProductTranslation(Base, TimestampMixin):
    __tablename__ = "product_translations"

    id = Column(Integer, primary_key=True)
    product_id = Column(
        Integer,
        ForeignKey("products.id", ondelete="CASCADE"),
        nullable=False
    )
    language = Column(String(5), nullable=False)
    title = Column(String, nullable=True)  # NULL = inherit
    description = Column(Text, nullable=True)
    short_description = Column(String(500), nullable=True)
    meta_title = Column(String(70), nullable=True)
    meta_description = Column(String(160), nullable=True)
    url_slug = Column(String(255), nullable=True)

    product = relationship("Product", back_populates="translations")

    OVERRIDABLE_FIELDS = [
        "title", "description", "short_description",
        "meta_title", "meta_description", "url_slug"
    ]

    def get_effective_title(self) -> str | None:
        if self.title is not None:
            return self.title
        return self._get_marketplace_translation_field("title")

    def _get_marketplace_translation_field(self, field: str) -> str | None:
        mp = self.product.marketplace_product
        if mp:
            for t in mp.translations:
                if t.language == self.language:
                    return getattr(t, field, None)
        return None

    __table_args__ = (
        UniqueConstraint("product_id", "language", name="uq_product_translation"),
        Index("idx_pt_product_language", "product_id", "language"),
    )
```

---

## Code Updates Required

### Files to Update

| File | Changes |
|------|---------|
| `models/database/__init__.py` | Export new models |
| `models/database/marketplace_product.py` | Add new fields, enums, relationship |
| `models/database/product.py` | Rename column, add override fields/properties |
| `models/schema/product.py` | Update Pydantic schemas |
| `app/services/product_service.py` | Add reset logic, translation support |
| `app/utils/csv_processor.py` | Update to use translations |
| `tests/` | Update all product-related tests |

### Import Service Updates

The CSV processor needs to:
1. Accept language parameter
2. Create/update translations instead of direct title/description
3. Parse prices to numeric
4. Detect digital products

---

## Open Questions (Requires Decision)

### 1. Keep Original Title/Description Columns?

**Option A: Keep as cache/fallback**
- Pros: Simpler migration, backward compatible
- Cons: Data duplication

**Option B: Remove after migration**
- Pros: Cleaner schema
- Cons: Breaking change, requires code updates

**Recommendation:** Option A for Phase 1, deprecate later

---

### 2. Default Language for Existing Data?

Current data appears to be English. Confirm before migration.

**Default:** `'en'`

---

### 3. Price Parsing Strategy?

**Option A: Parse during migration**
- Run Python migration to parse all existing prices

**Option B: Parse on next import only**
- Leave existing data, parse going forward

**Recommendation:** Option A - parse during migration for consistency

---

## Testing Checklist

Before running migrations in production:

- [ ] Run migrations on local database
- [ ] Run migrations on staging/test database with production data copy
- [ ] Verify data integrity after migration
- [ ] Run full test suite
- [ ] Test import with multi-language CSV
- [ ] Test override pattern (set override, reset to source)
- [ ] Test translation inheritance
- [ ] Performance test with large dataset

---

## Rollback Plan

If issues occur:

1. Migrations are designed to be reversible
2. Each migration has explicit downgrade function
3. Original data is preserved (title/description columns kept)
4. Run `alembic downgrade -1` for each migration in reverse order

---

## Next Steps

1. [ ] Confirm open questions above
2. [ ] Create Alembic migration files
3. [ ] Update SQLAlchemy models
4. [ ] Update Pydantic schemas
5. [ ] Update services
6. [ ] Update tests
7. [ ] Run on staging environment
8. [ ] Deploy to production
