package main

import (
	"context"
	"log"
	"math/rand"
	"strings"
	"time"
	"unicode/utf8"

	"github.com/kami/maven/internal/dialogue"
	"github.com/kami/maven/internal/router"
)

// clarifyTTL — how long a parked question stays answerable. Same 90s as the
// confirm gate, for the same reason: an answer is a same-breath gesture, and a
// stale question must not eat an unrelated later utterance.
const clarifyTTL = 90 * time.Second

// wantedSlots — what each intent needs before she can act on it. First entry is
// the one she asks about this turn; the rest are asked about on later turns, one
// per turn, as each answer lands (see askRemainingGap).
//
// Intents not listed here are never worth a question: note and query act on the
// raw utterance, chat and system have nothing to fill in. For those a clarify
// decision keeps the canned "не поняла" reply — inventing a question for noise
// is worse than admitting she missed it.
// A reminder wants BOTH what to remind about and when. Subject first: "напомни
// в 11" has a time and nothing to say at 11, and a reminder with no subject is
// not worth setting. Order here is the order she asks in.
var wantedSlots = map[router.Intent][]dialogue.Slot{
	router.IntentReminder: {dialogue.SlotText, dialogue.SlotTime},
	router.IntentFact:     {dialogue.SlotKey},
	router.IntentAct:      {dialogue.SlotFn},
}

// The questions themselves live in clarifytemplates.go, one list per slot,
// picked by attempt (Vikunja #457). The first ask is the short one this map
// used to hold; a re-ask says it differently, because a question he already
// failed to answer is the worst one to repeat unchanged.

// clarifyGaveUp — she is out of questions and still does not have the slot. She
// says so out loud: dropping the request in silence would leave him thinking it
// landed. Feminine self-reference ("поняла"), as everywhere.
const clarifyGaveUp = "Прости, я не поняла. Скажи, пожалуйста, по-другому."

// clarifyExpiredVariants — his answer came after the TTL, so the parked request
// is already gone. Same tone as clarifyGaveUp, different reason: too much time
// passed, not "I did not understand". Feminine self-reference ("ждала",
// "отпустила"); he is addressed with a plain imperative.
//
// Five phrasings, not one. This is the line he hears whenever he walks off
// mid-request, so it is the line that repeats most — and the same sentence every
// time is what makes a house assistant sound like a kiosk. They all carry the
// same two facts (the old request is gone; say it again if it still matters),
// because the wording may vary and the meaning may not.
//
// Fixed templates rather than model output, for the same reason as
// clarifyQuestions: this text has to be right every time, and it is not worth a
// generation to say something this small.
var clarifyExpiredVariants = []string{
	"Прости, я слишком долго ждала ответа и отпустила прошлую просьбу. Если она ещё нужна, скажи заново.",
	"Кажется, прошлая просьба уже не важна — я её отпустила. Если я ошибаюсь, повтори.",
	"Ты как-то резко замолчал, и я не стала ждать дальше. Если та просьба ещё нужна, скажи заново.",
	"Я не дождалась ответа и убрала прошлую просьбу. Повтори, если она всё ещё нужна.",
	"Столько времени прошло, что я отпустила прошлую просьбу. Скажи заново, если она в силе.",
}

// clarifyExpiredPluralVariants — the same notice when TWO parked requests died
// together (Vikunja #561). Since a side query suspends the flow instead of
// dropping it, the stack can hold both the flow and the thing he interrupted it
// with, and TakeExpired drops the whole stack when the top times out. "Прошлую
// просьбу" would then be a lie about the count: he loses two and hears about
// one.
//
// Two phrasings only, against five for the singular. This fires when he walks
// off in the middle of an interrupted exchange, which is rarer than walking off
// in the middle of a plain one, so it repeats less and needs less variety.
var clarifyExpiredPluralVariants = []string{
	"Прости, я слишком долго ждала и отпустила обе прошлые просьбы. Если они ещё нужны, скажи заново.",
	"Я не дождалась ответа и убрала обе прошлые просьбы. Повтори, если они всё ещё нужны.",
}

// clarifyExpiredLine picks one of them at random. n is how many requests died;
// anything above one gets the plural wording, because the bound is two today and
// a third would still be "обе" short of the truth only if MaxStackDepth grew.
func clarifyExpiredLine(n int) string {
	if n > 1 {
		return clarifyExpiredPluralVariants[rand.Intn(len(clarifyExpiredPluralVariants))]
	}
	return clarifyExpiredVariants[rand.Intn(len(clarifyExpiredVariants))]
}

// isClarifyExpired reports whether s opens with any of the expiry lines. The
// notice is glued in front of this turn's reply (see withNotice), so a caller
// checking for it has to match a prefix, not the whole string.
func isClarifyExpired(s string) bool {
	_, ok := cutClarifyExpired(s)
	return ok
}

// trimClarifyExpired strips a leading expiry notice, leaving this turn's actual
// reply. "" ⇒ the notice was the whole thing.
func trimClarifyExpired(s string) string {
	rest, ok := cutClarifyExpired(s)
	if !ok {
		return strings.TrimSpace(s)
	}
	return rest
}

// cutClarifyExpired matches either expiry deck as a prefix and returns what
// follows it. Both decks, since V-561 added the plural line: a caller asking
// "did she say a request timed out" means the fact, not which wording carried
// it, and a helper that knew only the singular would read the two-request
// notice as ordinary reply text.
func cutClarifyExpired(s string) (string, bool) {
	for _, deck := range [][]string{clarifyExpiredVariants, clarifyExpiredPluralVariants} {
		for _, v := range deck {
			if strings.HasPrefix(s, v) {
				return strings.TrimSpace(strings.TrimPrefix(s, v)), true
			}
		}
	}
	return "", false
}

// clarifyExpiredNotice returns that line when a parked question had just timed
// out, and "" when nothing was parked. Call it right after
// resolveClarifyAnswer: a live question is answered there, an expired one is
// only reported here — the words themselves still go on to be routed fresh.
func (h *reactiveHandler) clarifyExpiredNotice(ctx context.Context) string {
	if h.clarifyStore == nil {
		return ""
	}
	n := h.clarifyStore.TakeExpired(dialogueIDOf(ctx), h.now())
	if n == 0 {
		return ""
	}
	log.Printf("voice: clarify — %d parked question(s) expired, telling him and routing the words fresh", n)
	return clarifyExpiredLine(n)
}

// withNotice glues the expiry notice in front of this turn's reply. One turn
// carries one reply on the wire, so the notice cannot be a message of its own —
// but neither the notice nor the fresh answer may be dropped.
func withNotice(notice, reply string) string {
	if notice == "" {
		return reply
	}
	if reply == "" {
		return notice
	}
	return notice + " " + reply
}

// withResumed puts the resumed question on the END of this turn's reply, where
// withNotice puts the expiry notice on the front (Vikunja #561).
//
// The order is the owner's: "в Риме сейчас ..., на какое время поставить
// напоминание?" — answer first, then the open question. A question in front of
// its own answer would read as ignoring what he asked.
//
// Two sentences, not one (V-654). This used to fold the answer's full stop into
// a comma, on the strength of the owner having written it that way once. Spliced
// onto a real answer it reads as one run-on thought — "вот что я нашла: вайфай
// пароль лежит в ящике стола, на какое время поставить напоминание?" — and the
// question disappears into the tail of a sentence about something else. A reply
// with no terminator of its own is given one, so the join never depends on how
// the phraser chose to end.
//
// A resume with no answer in front of it is just the question.
func withResumed(reply, resumed string) string {
	if resumed == "" {
		return reply
	}
	reply = strings.TrimSpace(reply)
	if reply == "" {
		return resumed
	}
	if !endsSentence(reply) {
		reply += "."
	}
	return reply + " " + resumed
}

// endsSentence reports whether s already closes itself. The ellipsis counts: a
// trailing "…" is a deliberate end, and a full stop after it reads as a typo.
func endsSentence(s string) bool {
	r, _ := utf8.DecodeLastRuneInString(s)
	return strings.ContainsRune(".!?…", r)
}

// missingFor returns the slots a decision still needs, most important first.
// Empty ⇒ there is nothing identifiable to ask about.
func missingFor(dec router.Decision) []dialogue.Slot {
	return stillMissingFor(dec.Intent, dec.Utterance, toDialogueSlots(dec.Slots))
}

// clarifyQuestion picks the one question to ask for a clarify decision. Returns
// ("", false) when she has no idea what is missing.
//
// One question about one thing: if two slots are missing she asks about the
// first only. Two questions in one breath is an interrogation. The second gap
// is picked up on the turn after the first one is answered (askRemainingGap).
func (h *reactiveHandler) clarifyQuestion(dec router.Decision) (dialogue.Slot, string, bool) {
	missing := missingFor(dec)
	if len(missing) == 0 {
		return "", "", false
	}
	q, ok := h.questionFor(missing[0], 1, dec.Utterance, toDialogueSlots(dec.Slots), "")
	if !ok {
		return "", "", false
	}
	return missing[0], q, true
}

// questionFor picks the wording for one gap. Every slot but the reminder's time
// reads its deck by attempt; the time asks about whichever of the hour, the half
// of the day and the day he has not said, and states the clock while it does
// (V-579).
//
// taken is the acknowledgement of what his last turn added, empty when it added
// nothing and empty for a first ask, which has no turn behind it (V-593).
func (h *reactiveHandler) questionFor(slot dialogue.Slot, attempt int, utterance string, s dialogue.Slots, taken string) (string, bool) {
	if slot != dialogue.SlotTime {
		return clarifyQuestionFor(slot, attempt)
	}
	return whenQuestion(whenGapOf(utterance, s.HasTime), attempt, h.now(), taken)
}

// askClarify parks the request and returns the question to ask instead of the
// canned "не поняла". Returns ("", false) when there is nothing to ask about, so
// the caller falls back to the canned reply.
func (h *reactiveHandler) askClarify(ctx context.Context, dec router.Decision) (string, bool) {
	if h.clarifyStore == nil {
		return "", false
	}
	slot, question, ok := h.clarifyQuestion(dec)
	if !ok {
		return "", false
	}
	// An act she could not resolve is a refusal, not a question (Vikunja #556).
	if slot == dialogue.SlotFn {
		log.Printf("voice: clarify — act %q matched no capability; saying so instead of asking", dec.Utterance)
		return actNotRecognized, true
	}
	q := &dialogue.PendingQuestion{
		Intent:      dialogue.Intent(dec.Intent),
		Slots:       toDialogueSlots(dec.Slots),
		Missing:     []dialogue.Slot{slot},
		Utterance:   dec.Utterance,
		Asked:       h.now(),
		TTL:         clarifyTTL,
		Attempts:    1, // this ask
		MaxAttempts: h.clarifyMaxAttempts,
	}
	// Push, not Put, when this turn suspended a flow (Vikunja #561): the side
	// query needs clarifying of ITS own, and Put would replace the top of the
	// stack — which is the very question the side query was allowed to interrupt
	// rather than kill. Push keeps both.
	//
	// Push returns whatever the depth bound forced out, and that one has to be
	// spoken: MaxStackDepth is a promise that every level she keeps is a level
	// she can name when it dies. It is glued in front, like every other notice
	// about something let go.
	rt := turnRouteFrom(ctx)
	if rt != nil && rt.suspended {
		if evicted := h.clarifyStore.Push(dialogueIDOf(ctx), q); evicted != nil {
			log.Printf("voice: clarify — stack full at %d, letting go of the request behind %q", dialogue.MaxStackDepth, evicted.Utterance)
			rt.dropped = withNotice(rt.dropped, clarifyDropped)
		}
		// One question per breath still holds. The side query turned out to need
		// a question of its own, so THAT is the one she asks; resuming as well
		// would put two questions in one reply, which is the interrogation
		// askRemainingGap already refuses to run. The suspended flow keeps its
		// place underneath and is not lost — if it is never reached it dies on
		// the TTL, and the expiry notice (now plural-aware) says so.
		rt.resume = ""
		log.Printf("voice: clarify — asked about %s for intent=%s, stacked on a suspended flow", slot, dec.Intent)
		return question, true
	}
	h.clarifyStore.Put(dialogueIDOf(ctx), q)
	log.Printf("voice: clarify — asked about %s for intent=%s", slot, dec.Intent)
	return question, true
}

// clarifyCancelled — he called the half-built request off. Said out loud, like
// every other way it can end: a silent drop reads as "done". Feminine
// self-reference ("отменила"), as everywhere.
const clarifyCancelled = "Хорошо, отменила."

// clarifyDropped — he asked for something ELSE instead, so the parked request
// is gone. Glued in front of the answer to what he actually asked, because
// nothing may be dropped in silence.
//
// Only new_request and cancel reach this since V-561. A side query used to as
// well, and the owner rejected it on sight: he asks about the weather in the
// middle of setting a reminder, and hearing "прошлую просьбу отпускаю" tells him
// a thing he did not ask to lose has been lost. It had not been — there was
// simply nowhere to put it. Now there is (ClarifyStore's stack), so a side query
// suspends and resumes, and apologising for a drop that did not happen is worse
// than saying nothing.
const clarifyDropped = "Прошлую просьбу отпускаю."

// resolveClarifyAnswer reads an utterance against the parked question and
// decides what it IS before deciding what to do with it. Returns ("", false)
// when the turn is not this resolver's — nothing parked, or the utterance turned
// out to be a request of its own — so the caller dispatches it normally.
//
// The order is the point (Vikunja #560). The utterance is ROUTED first, and the
// role is read off that decision: a routed decision that stands on its own is
// not an answer, whatever the extractor found inside it. Before this the
// extractor decided, so "какая сейчас погода в Риме?" became the time of a
// reminder on the strength of the word "сейчас".
//
// The answer itself is parsed with the same extractor the router uses, for the
// intent she parked — no second parser. If it still does not fill the gap she
// asks again, up to MaxAttempts; after that she says out loud that she did not
// understand. She never drops the request in silence.
func (h *reactiveHandler) resolveClarifyAnswer(ctx context.Context, text string) (string, bool) {
	if h.clarifyStore == nil {
		return "", false
	}
	q := h.clarifyStore.Get(dialogueIDOf(ctx), h.now())
	if q == nil {
		return "", false // not_applicable: nothing is pending
	}

	intent := router.Intent(q.Intent)
	answer := h.extractor.Extract(ctx, intent, text, h.now())

	var (
		routed   router.Decision
		routedOK bool
	)
	if needsRoute(text) {
		routed, routedOK = h.routeForRole(ctx, text)
	}
	role := classifyTurnRole(q, text, toDialogueSlots(answer), routed, routedOK)
	log.Printf("voice: clarify — %q is a %s against %s (routed=%v)", text, role, dialogue.CapabilityFor(q.Intent), routedOK)

	switch role {
	case roleCancel:
		h.clarifyStore.Delete(dialogueIDOf(ctx))
		return clarifyCancelled, true
	case roleSideQuery:
		// He asked something of his own WITHOUT leaving the flow. The question
		// stays exactly where it is — same slot, same attempt, same parked
		// utterance — and these words go on to be answered as themselves. The
		// resumed question is then glued onto the back of that answer, so one
		// reply carries both acts (Vikunja #561).
		//
		// No attempt is spent. He answered the side query, not the parked
		// question, and charging a retry for a turn that was never an answer is
		// the V-554 shape.
		h.noteSuspended(ctx, q)
		return "", false
	case roleAside:
		// He stated something in the middle of the flow. Same machinery as a
		// side query and for the same reason: the words are answered as
		// themselves, so the note or the fact is stored, and the question comes
		// back on the end of the same reply (V-577 shape 2). Storing it in
		// silence and dropping it in silence are both wrong, and dropping it is
		// what she did.
		h.noteSuspended(ctx, q)
		return "", false
	case roleNewRequest:
		// He moved on. A parked question used to swallow whatever came next, so
		// one act she could not fulfil ate the following three turns (Vikunja
		// #554) and a world question set a reminder for a time nobody asked for
		// (#558). Drop the question, say so, and let these words be themselves.
		h.clarifyStore.Delete(dialogueIDOf(ctx))
		h.noteDropped(ctx)
		return "", false
	}

	// He is answering, so the run of step-asides is over (V-654). Reset here
	// rather than where a gap is FILLED: "позвонить маме" against a question
	// about the time gives her nothing she asked for and still means he is in
	// the exchange, and the retry it costs is bound enough on its own. The
	// counter is for the case the bounds miss — he asked for other things and
	// never came back.
	q.Suspends = 0

	merged := q.Answer(text, toDialogueSlots(answer))
	// Fold a newly answered subject into the raw utterance. Downstream actions
	// phrase from Utterance, not from the text slot — actionReminder stores it
	// as the reminder payload — so a reminder clarified out of a bare "напомни"
	// would fire at 11:00 saying "напомни" and nothing else.
	q.Utterance = foldAnswerIntoUtterance(q.Utterance, merged.Text)
	// A fact answers with a key and a value and fills no Text slot at all, so
	// the fold above leaves the utterance at the bare "запиши" — and that is
	// what the confirmation now reads back to him (V-592). His raw words are the
	// only record of what he said, so they are what is folded. Never for a time
	// question: what he says about when is kept apart in WhenText on purpose,
	// or the reminder would read the day back at him when it fires.
	if merged.Text == "" && !asksAboutTime(q.Missing) {
		q.Utterance = foldAnswerIntoUtterance(q.Utterance, text)
	}
	// An answer about the time joins everything else he has said about the time,
	// and the whole of it is re-read as one request (V-579). "завтра" names the
	// day of an hour she is already holding, and read alone it names no hour at
	// all, so the parser would have nothing and she would ask for ever.
	// What he had already said about the time, read BEFORE this answer joins it.
	// A re-ask that cannot tell the two apart is the one that repeats itself
	// byte for byte (V-593).
	var taken string
	if asksAboutTime(q.Missing) {
		before := whenKnownOf(whenTextOf(q), q.Slots.HasTime)
		q.WhenText = strings.TrimSpace(q.WhenText + " " + text)
		if t, ok := h.readWhen(ctx, intent, q, text); ok {
			merged.Time, merged.HasTime = t, true
		}
		if before.movedForward(whenKnownOf(whenTextOf(q), merged.HasTime)) {
			taken = whenTakenLine(text)
		}
	}
	if stillOpen(q.Missing, whenTextOf(q), merged) {
		return h.reaskOrGiveUp(ctx, q, merged, text, taken), true
	}
	h.clarifyStore.Delete(dialogueIDOf(ctx))

	// One gap filled is not the same as a complete request. askClarify parks
	// only the first gap, because one question per turn is the rule, but a
	// reminder wants both a subject and a time. "напомни" with neither used to
	// ask "О чём напомнить?", accept "позвонить маме", and then hand applyAction
	// a reminder with no time, which answered "не получилось разобрать время
	// напоминания." — an error for a request she never finished asking about.
	// Re-enter the loop instead, one question at a time as before.
	if reply, asked := h.askRemainingGap(ctx, q, intent, merged); asked {
		return reply, true
	}

	// Rebuild the decision as if it had routed cleanly, then run it down the
	// normal path. Clarify is deliberately false and the intent is unchanged:
	// filling in an argument never grants authority, so the completed decision
	// still meets the allowlist and the destructive-act confirm gate in
	// applyAction exactly like any other decision.
	dec := router.Decision{
		Utterance: q.Utterance,
		Stage:     2,
		Intent:    intent,
		Slots:     applyDialogueSlots(answer, merged),
	}
	return h.finishClarified(ctx, dec), true
}

// noteDropped records that the parked request was let go this turn, so runTurn
// can say it in front of whatever these words are answered with. Nothing to
// record outside runTurn — a unit test calling one resolver has no turn to glue
// a notice onto.
func (h *reactiveHandler) noteDropped(ctx context.Context) {
	if rt := turnRouteFrom(ctx); rt != nil {
		rt.dropped = clarifyDropped
	}
}

// noteSuspended keeps the parked question alive across a side query and records
// the words that bring it back, so runTurn can put them after this turn's answer
// (Vikunja #561).
//
// Two things happen to the question and neither is an attempt. Its clock is
// restarted, because she is about to ask it again and the 90s TTL measures the
// pause since she last spoke it — leaving Asked at the original ask would let a
// flow he is actively working through die of a wait he did not take. And the
// stack is left exactly as it is: the question is already on top, so suspending
// it is not a write.
//
// A slot with no resumed wording (clarifyResumedFor says so) resumes nothing and
// says nothing. She must not claim to be holding a question she cannot re-ask.
//
// Suspension is bounded, since V-654. Neither of the two things above is a
// limit: no attempt is spent, and restarting the clock means the TTL cannot
// arrive while he keeps talking. So the count is the only thing that ends it,
// and past MaxSuspends she lets the request go and says so with the same line
// every other drop uses. The rule is unchanged — a question ends by being
// answered or by being let go out loud — this only recognises three unrelated
// requests in a row as the second of those.
func (h *reactiveHandler) noteSuspended(ctx context.Context, q *dialogue.PendingQuestion) {
	rt := turnRouteFrom(ctx)
	if rt == nil || len(q.Missing) == 0 {
		return
	}
	question, ok := clarifyResumedFor(q.Missing[0])
	if !ok {
		return
	}
	if !q.CanResume() {
		h.clarifyStore.Delete(dialogueIDOf(ctx))
		h.noteDropped(ctx)
		log.Printf("voice: clarify — the question about %s stepped aside %d times; letting the request go", q.Missing[0], q.Suspends)
		return
	}
	q.Suspends++
	q.Asked = h.now()
	h.clarifyStore.Put(dialogueIDOf(ctx), q)
	rt.resume = question
	rt.suspended = true
	log.Printf("voice: clarify — is its own request; suspending the question about %s and resuming it in the same reply (suspend %d of %d)", q.Missing[0], q.Suspends, dialogue.MaxSuspends)
}

// foldAnswerIntoUtterance appends an answered subject to the original words,
// unless they already carry it. "напомни" + "позвонить маме" reads as the
// request he would have made in one breath. Nothing is appended when the
// subject is empty or already present, so re-asking the same question twice
// cannot grow the utterance.
func foldAnswerIntoUtterance(utterance, subject string) string {
	subject = strings.TrimSpace(subject)
	if subject == "" || strings.Contains(utterance, subject) {
		return utterance
	}
	if strings.TrimSpace(utterance) == "" {
		return subject
	}
	return strings.TrimSpace(utterance) + " " + subject
}

// askRemainingGap re-parks the request when the answer closed one gap and
// wantedSlots still names another. Returns ("", false) when the request is
// complete, when there is no question for what is left, or when she is out of
// attempts — in all three the caller runs the decision as it stands, which for
// the out-of-attempts case is the old behaviour and is the right one: she has
// already asked enough.
//
// The attempt budget is shared with the re-ask path on purpose. A second gap
// costs a question exactly like a second try at the first one does, so the cap
// still bounds how many times she can speak before acting or letting go.
func (h *reactiveHandler) askRemainingGap(ctx context.Context, q *dialogue.PendingQuestion, intent router.Intent, merged dialogue.Slots) (string, bool) {
	remaining := stillMissingFor(intent, whenTextOf(q), merged)
	if len(remaining) == 0 {
		return "", false
	}
	// Attempts+1 is the question she is about to ask, and the budget is shared
	// with the re-ask path, so the second gap is worded like a second try.
	question, ok := h.questionFor(remaining[0], q.Attempts+1, whenTextOf(q), merged, "")
	if !ok || !q.CanAsk() {
		return "", false
	}
	// Suspends is not carried, and by this point it is already zero: the answer
	// path resets it (V-654). Left off the literal so the zero is stated where
	// the struct is built, rather than inherited from a field nobody names.
	h.clarifyStore.Put(dialogueIDOf(ctx), &dialogue.PendingQuestion{
		Intent:      q.Intent,
		Slots:       merged,
		Missing:     []dialogue.Slot{remaining[0]},
		Utterance:   q.Utterance,
		WhenText:    q.WhenText,
		Asked:       h.now(),
		TTL:         clarifyTTL,
		Attempts:    q.Attempts + 1,
		MaxAttempts: q.MaxAttempts,
	})
	log.Printf("voice: clarify — one gap filled, still missing %s for intent=%s, asking again (attempt %d)", remaining[0], intent, q.Attempts+1)
	return question, true
}

// reaskOrGiveUp handles an answer that left the gap open: ask the same question
// again while she has attempts left, otherwise say she did not understand and
// let the request go. Never returns "" — a mute give-up reads as "done".
// taken is the acknowledgement of what this answer DID give, empty when it gave
// nothing (V-593). The give-up line never carries it: it is not another ask.
func (h *reactiveHandler) reaskOrGiveUp(ctx context.Context, q *dialogue.PendingQuestion, merged dialogue.Slots, text, taken string) string {
	question := ""
	if len(q.Missing) > 0 {
		question, _ = h.questionFor(q.Missing[0], q.Attempts+1, whenTextOf(q), merged, taken)
	}
	if question == "" || !q.CanAsk() {
		h.clarifyStore.Delete(dialogueIDOf(ctx))
		log.Printf("voice: clarify — gave up on %v after %d question(s), answer was %q", q.Missing, q.Attempts, text)
		return clarifyGaveUp
	}
	// Re-park with whatever the answer DID give, the clock restarted and one
	// more question spent.
	q.Slots = merged
	q.Attempts++
	q.Asked = h.now()
	h.clarifyStore.Put(dialogueIDOf(ctx), q)
	log.Printf("voice: clarify — answer %q did not fill %v, asking again (attempt %d)", text, q.Missing, q.Attempts)
	return question
}

// finishClarified runs a completed decision through the same steps a freshly
// routed one takes: remember the turn, act, then phrase.
func (h *reactiveHandler) finishClarified(ctx context.Context, dec router.Decision) string {
	if h.dialogueSessions != nil {
		now := h.now()
		prev := h.dialogueSessions.Get(dialogueIDOf(ctx), now)
		dec = followUpMerge(prev, dec, now)
		h.rememberTurn(ctx, prev, dec, now)
	}
	reply := h.applyAction(ctx, dec)
	if reply == "" {
		reply = h.replier.Reply(ctx, dec)
	}
	if reply == "" {
		// Belt: an empty reply here would be a silent drop.
		reply = clarifyGaveUp
	}
	return reply
}

// maxCarriedHistory — how many turns of PRIOR history (beyond the immediate
// last turn) rememberTurn carries forward. The session ends up holding this
// many plus the one just-finished turn, so callers describing the total
// depth (chatHistory's doc comment, this one) say "up to 4".
const maxCarriedHistory = 3

// rememberTurn stores this turn as the dialogue session the next follow-up
// inherits from, carrying up to 4 prior turns of history for anaphora. Capped so
// one long conversation can't grow the session unboundedly.
func (h *reactiveHandler) rememberTurn(ctx context.Context, prev *dialogue.Session, dec router.Decision, now time.Time) {
	var history []dialogue.Turn
	if prev != nil {
		history = append(history, sessionAsTurn(prev))
		maxHist := len(prev.History)
		if maxHist > maxCarriedHistory {
			maxHist = maxCarriedHistory
		}
		history = append(history, prev.History[:maxHist]...)
	}
	ttl := time.Duration(0) // use the store default (2 min)
	if dec.Intent == router.IntentChat {
		ttl = 15 * time.Minute // conversational turns should last longer
	}
	// A system or query turn often carries no Text slot at all — a stage-0
	// grammar fills none. The next turn may be an ellipsis ("а завтра?"),
	// which knows the day but not what was asked ABOUT, so keep the raw
	// utterance where continuation.go can find it. Only these two intents:
	// everywhere else Text is a payload and must stay what the router put in.
	//
	// Overwritten, not filled: rememberTurn runs AFTER followUpMerge, which
	// has already inherited a Text from the previous same-intent turn, so a
	// fill-if-empty rule keeps the OLD topic for ever. Seen on the deployed
	// daemon 01-08-2026 — "во сколько у меня встреча" then "какие у меня
	// планы" then "а завтра?" continued the meeting, two turns stale.
	//
	// A continuation is the exception and keeps what it inherited: its
	// utterance is the ellipsis, and the topic it carries is the real one.
	slots := toDialogueSlots(dec.Slots)
	if !dec.Continued && (dec.Intent == router.IntentSystem || dec.Intent == router.IntentQuery) {
		slots.Text = dec.Utterance
	}
	h.dialogueSessions.Put(dialogueIDOf(ctx), &dialogue.Session{
		Intent:    dialogue.Intent(dec.Intent),
		Slots:     slots,
		Timestamp: now,
		TTL:       ttl,
		History:   history,
	})
}