langfuse

type AgentUsageStats struct {
	// AgentName is the trace name (i.e. the agent identifier) in Langfuse.
	AgentName string `json:"agent_name"`
	// TotalCost is the total cost in USD for all observations belonging to
	// this agent's traces within the queried time window.
	TotalCost float64 `json:"total_cost"`
	// InputTokens is the sum of input tokens consumed across all observations.
	InputTokens float64 `json:"input_tokens"`
	// OutputTokens is the sum of output tokens produced across all observations.
	OutputTokens float64 `json:"output_tokens"`
	// TotalTokens is the sum of all tokens consumed across all observations.
	TotalTokens float64 `json:"total_tokens"`
	// Count is the total number of observations for this agent.
	Count float64 `json:"count"`
}

type Client interface {
	// GetPrompt returns the prompt template by name, or the default if not found/disabled.
	GetPrompt(ctx context.Context, name, defaultPrompt string) string

	// GetAgentStats returns aggregated token usage and cost statistics per
	// agent (trace name) for the duration specified in the request. Without
	// this method, consumers would need to call the Langfuse metrics API
	// directly, duplicating auth and parsing logic.
	GetAgentStats(ctx context.Context, req GetAgentStatsRequest) ([]AgentUsageStats, error)
}

type Config struct {
	PublicKey     string `json:"public_key" toml:"public_key,omitempty" yaml:"public_key,omitempty"`
	SecretKey     string `json:"secret_key" toml:"secret_key,omitempty" yaml:"secret_key,omitempty"`
	Host          string `json:"host" toml:"host,omitempty" yaml:"host,omitempty"`
	EnablePrompts bool   `json:"enable_prompts" toml:"enable_prompts,omitempty" yaml:"enable_prompts,omitempty"`
}

type GetAgentStatsRequest struct {
	// Duration is the lookback period from now (e.g. 24h, 7*24h).
	Duration time.Duration
	// AgentName optionally restricts the query to a single agent.
	// When empty, stats for all agents are returned.
	AgentName string
}