llm

type Codec interface {
	// DecomposeRequest breaks a request body into policy calls.
	// Returns the calls and an opaque handle for ReassembleRequest.
	DecomposeRequest(body []byte, scope string, cfg DecomposeConfig) ([]keep.Call, any, error)

	// DecomposeResponse breaks a response body into policy calls.
	// Returns the calls and an opaque handle for ReassembleResponse.
	DecomposeResponse(body []byte, scope string, cfg DecomposeConfig) ([]keep.Call, any, error)

	// ReassembleRequest patches mutations into the request using the
	// handle from DecomposeRequest. Returns original body if no mutations.
	ReassembleRequest(handle any, results []keep.EvalResult) ([]byte, error)

	// ReassembleResponse patches mutations into the response.
	ReassembleResponse(handle any, results []keep.EvalResult) ([]byte, error)

	// ReassembleStream reassembles provider-specific SSE events into a
	// complete response body suitable for DecomposeResponse.
	ReassembleStream(events []sse.Event) (body []byte, err error)

	// SynthesizeEvents creates replacement SSE events from a patched
	// response body (the output of ReassembleResponse after redaction).
	SynthesizeEvents(patchedBody []byte) ([]sse.Event, error)
}

type DecomposeConfig struct {
	// ToolResult decomposes tool_result blocks (default: true).
	ToolResult *bool
	// ToolUse decomposes tool_use blocks (default: true).
	ToolUse *bool
	// Text decomposes text content blocks (default: false).
	Text *bool
	// RequestSummary emits an llm.request summary call (default: true).
	RequestSummary *bool
	// ResponseSummary emits an llm.response summary call (default: true).
	ResponseSummary *bool
}

type Result struct {
	// Decision is the aggregate policy decision: Allow, Deny, or Redact.
	Decision keep.Decision
	// Rule is the name of the rule that triggered a Deny or the first Redact.
	// Empty for Allow decisions.
	Rule string
	// Message is the deny message from the triggering rule.
	Message string
	// Body is the (possibly redacted) request or response JSON.
	// For Allow decisions, this is the original body unchanged.
	// For Redact decisions, mutations have been applied.
	// For Deny decisions, this is nil.
	Body []byte
	// Audits contains one AuditEntry per decomposed call that was evaluated.
	Audits []keep.AuditEntry
}

type StreamResult struct {
	// Decision is the aggregate policy decision.
	Decision keep.Decision
	// Rule is the name of the triggering rule.
	Rule string
	// Message is the deny message.
	Message string
	// Events contains the SSE events to send to the client.
	// For Allow decisions, these are the original events.
	// For Redact decisions, these are synthesized from the patched response.
	// For Deny decisions, this is nil.
	Events []sse.Event
	// Body is the reassembled (and possibly redacted) response JSON.
	// Useful for logging/debugging the complete response after policy.
	// For Deny decisions, this is nil.
	Body []byte
	// RawBody is the reassembled response JSON before policy evaluation.
	// Consumers can use this for pre-policy logging without re-reassembling
	// the stream. For Deny decisions, this is still populated.
	RawBody []byte
	// Audits contains one AuditEntry per decomposed call that was evaluated.
	Audits []keep.AuditEntry
}