package message

// Usage tracks token consumption for a single API turn.
type Usage struct {
	InputTokens         int64 `json:"input_tokens"`
	OutputTokens        int64 `json:"output_tokens"`
	CacheReadTokens     int64 `json:"cache_read_tokens,omitempty"`
	CacheCreationTokens int64 `json:"cache_creation_tokens,omitempty"`
}

func (u Usage) TotalTokens() int64 {
	return u.InputTokens + u.OutputTokens
}

func (u *Usage) Add(other Usage) {
	u.InputTokens += other.InputTokens
	u.OutputTokens += other.OutputTokens
	u.CacheReadTokens += other.CacheReadTokens
	u.CacheCreationTokens += other.CacheCreationTokens
}