# PhoneHub Changes Summary

## Changes Made Based on Feedback

### 1. Removed User Ownership from PhoneNumber ✅

**Before:**
```python
class PhoneNumber:
    user = ForeignKey("account.User")  # ❌ Tied to specific user
    group = ForeignKey("account.Group")
```

**After:**
```python
class PhoneNumber:
    # No user or group fields ✅
    # Pure cache - shared across entire system
```

**Reason**: PhoneNumber is a lookup cache, not user data. Sharing cached lookups across the system minimizes Twilio API charges.

### 2. Removed Group Ownership from PhoneNumber ✅

**Before:**
```python
phone_number = unique_together with group  # Different cache per org
```

**After:**
```python
phone_number = unique=True  # One cache entry system-wide
```

**Reason**: To maximize cache hits and minimize costs. If the same number is looked up by different organizations, they share the cached data.

### 3. Added Caller Name Verification ✅

**New Fields:**
- `caller_name`: Registered owner/subscriber name from carrier
- `caller_type`: BUSINESS or CONSUMER
- `address_line1`, `address_city`, `address_state`, `address_zip`, `address_country`

**Twilio Integration:**
```python
lookup = client.lookups.v2.phone_numbers(phone_number).fetch(
    fields='line_type_intelligence,caller_name'  # ✅ Added caller_name
)
```

**Usage:**
```python
phone = phonehub.lookup('+14155551234')
print(f"Registered to: {phone.caller_name}")  # "ACME Corp" or "John Smith"
print(f"Type: {phone.caller_type}")  # "BUSINESS" or "CONSUMER"
```

## Architecture Decision

### Shared Cache Strategy

```
PhoneConfig (per-org) ──► Lookup API Credentials
                          │
                          ▼
                     Twilio API
                          │
                          ▼
PhoneNumber (shared) ──► Global Cache
     ▲
     │ (reference only)
     │
SMS (per-org) ──────► Message Records
```

**Benefits:**
1. ✅ Minimize API charges (share cache across system)
2. ✅ Simple architecture (one number = one cache entry)
3. ✅ Per-org configs (credentials, settings)
4. ✅ Per-org SMS tracking (audit trail)

## Updated Models

### PhoneNumber (Pure Cache)
```python
class PhoneNumber(models.Model, MojoModel):
    """
    Pure cache - shared across entire system to minimize Twilio API charges.
    """
    phone_number = CharField(unique=True)  # One entry per number
    
    # Carrier/Line Type
    carrier = CharField()
    line_type = CharField()
    is_mobile = BooleanField()
    is_voip = BooleanField()
    
    # Caller Identity (NEW)
    caller_name = CharField()      # ✅ Registered owner
    caller_type = CharField()      # ✅ BUSINESS/CONSUMER
    address_* = CharField()        # ✅ Address fields
    
    # Cache Management
    lookup_expires_at = DateTimeField()
    lookup_count = IntegerField()
    last_lookup_at = DateTimeField()
```

### PhoneConfig (Per-Organization)
```python
class PhoneConfig(MojoSecrets, MojoModel):
    """
    Provider configuration - can be system-wide or per-organization.
    """
    group = OneToOneField("account.Group", null=True)  # Optional
    provider = CharField()  # twilio or aws
    
    # Credentials stored in mojo_secrets (encrypted)
    # - twilio_account_sid
    # - twilio_auth_token
    # - aws_access_key_id
    # - aws_secret_access_key
```

### SMS (Per-Organization)
```python
class SMS(models.Model, MojoModel):
    """
    Message records - tracked per user/organization for audit trail.
    """
    user = ForeignKey("account.User", null=True)   # Who sent it
    group = ForeignKey("account.Group", null=True)  # Which org
    
    direction = CharField()  # outbound/inbound
    from_number = CharField()
    to_number = CharField()
    body = TextField()
    status = CharField()
```

## API Remains Unchanged

The simple API still works exactly the same:

```python
from mojo.apps import phonehub

# Normalize
num = phonehub.normalize('415-555-1234')

# Lookup (now includes caller name)
phone = phonehub.lookup('+14155551234')
print(phone.caller_name)  # ✅ NEW: Registered owner

# Send SMS
sms = phonehub.send_sms('+14155551234', 'Hello!')
```

## Cost Implications

### Caller Name Lookup
- **Base lookup**: ~$0.005
- **Caller name add-on**: ~$0.010
- **Total**: ~$0.015 per lookup

### Cache Savings Example

**Scenario**: 5 different users lookup same number in 30 days

**Without cache (per-user storage)**:
- 5 lookups × $0.015 = $0.075

**With shared cache**:
- 1 lookup × $0.015 = $0.015
- 4 cache hits × $0.00 = $0.00
- **Total: $0.015 (80% savings)**

## Migration Required

⚠️ **Database changes required**:

```bash
# You'll need to run migrations
python manage.py makemigrations phonehub
python manage.py migrate phonehub
```

**Changes:**
- Remove `user` field from PhoneNumber
- Remove `group` field from PhoneNumber
- Change `phone_number` to unique (remove unique_together)
- Add `caller_name`, `caller_type`, address fields

## Documentation Added

1. **CALLER_NAME_INFO.md** - Everything about caller name lookups
2. **ARCHITECTURE.md** - Design decisions and cache strategy
3. **CHANGES_SUMMARY.md** - This file

## Key Takeaways

✅ **PhoneNumber = Pure Cache**: No user/group ownership, shared system-wide  
✅ **Caller Name Verification**: New feature via Twilio CNAM lookup  
✅ **Cost Optimization**: Shared cache minimizes duplicate lookups  
✅ **Simple API**: No changes to public API  
✅ **Per-Org Configs**: PhoneConfig still supports multi-tenancy  
✅ **Per-Org SMS**: SMS records still tracked per organization  

## Next Steps

1. Run migrations to update database schema
2. Test caller name lookups with your Twilio account
3. Monitor `lookup_count` to track API usage and costs
4. Adjust `lookup_cache_days` if needed for your use case
