package daemon

import "strings"

// FailureReason values for tasks that "completed" with output but the
// output is actually a known agent fallback marker — i.e. the agent gave
// up and emitted a meta message instead of a real result. Listed here so
// the server-side query GetLastTaskSession can filter them out and a
// rerun starts from a fresh agent session instead of resuming the same
// poisoned conversation.
const (
	FailureReasonIterationLimit   = "iteration_limit"
	FailureReasonAgentFallbackMsg = "agent_fallback_message"
)

// poisonedOutputMaxLen caps how long an output can be and still be
// classified as a poisoned fallback. Real fallback messages are short,
// one-sentence affairs; a long output that happens to mention a marker
// is almost certainly a real conclusion (e.g. a code-review reply
// quoting these strings, like the one currently quoting them in
// MUL-1630). The cap intentionally errs on the side of NOT classifying
// — a missed poisoned task gets retried by user action, but a
// false-positive turns a successful task into a failure and a system
// comment.
const poisonedOutputMaxLen = 320

// poisonedMarkers maps a substring fingerprint of a known agent fallback
// terminal message to its failure_reason classifier. Match is case-
// insensitive and substring-based; the cap above prevents long outputs
// that quote a marker from being misclassified.
var poisonedMarkers = []struct {
	Substring string
	Reason    string
}{
	{"i reached the iteration limit", FailureReasonIterationLimit},
	{"put your final update inside the content string", FailureReasonAgentFallbackMsg},
}

// classifyPoisonedOutput reports whether output matches a known agent
// fallback terminal message and, if so, returns the failure_reason that
// should be persisted on the task row. Long outputs are never
// classified: a real fallback is the agent's only utterance for the
// turn, so anything beyond ~one paragraph is treated as a real result
// even if it contains a marker substring.
func classifyPoisonedOutput(output string) (string, bool) {
	trimmed := strings.TrimSpace(output)
	if trimmed == "" || len(trimmed) > poisonedOutputMaxLen {
		return "", false
	}
	lowered := strings.ToLower(trimmed)
	for _, m := range poisonedMarkers {
		if strings.Contains(lowered, m.Substring) {
			return m.Reason, true
		}
	}
	return "", false
}