from typing import Any, Dict, Optional


class CBFRecord(Dict[str, Any]):
    """CloudZero Billing Format (CBF) record structure.
    
    This class represents a CBF record that is created from LiteLLM usage data 
    for CloudZero integration. Since CBF field names contain forward slashes 
    (e.g., 'time/usage_start', 'cost/cost'), we use a Dict base class rather 
    than TypedDict to accommodate the special characters in field names.
    
    Expected CBF fields:
    - time/usage_start: ISO-formatted UTC datetime (Optional[str])
    - cost/cost: Billed cost (float)
    - resource/id: CloudZero Resource Name (CZRN) (str)
    - usage/amount: Numeric value of tokens consumed (int)
    - usage/units: Description of units, e.g., 'tokens' (str)
    - resource/service: Maps to CZRN service-type, e.g., 'litellm' (str)
    - resource/account: Maps to CZRN owner-account-id (entity_id) (str)
    - resource/region: Maps to CZRN region, e.g., 'cross-region' (str)
    - resource/usage_family: Maps to CZRN resource-type, e.g., 'llm-usage' (str)
    - lineitem/type: Standard usage line item, e.g., 'Usage' (str)
    - resource/tag:provider: CZRN provider component (str)
    - resource/tag:model: CZRN cloud-local-id component (model) (str)
    - resource/tag:{key}: Various resource tags for dimensions and metrics (Optional[str])
    """
    pass


# Type alias for better readability in function signatures
CBFRecordDict = Dict[str, Any]