package main

import (
	"testing"
	"time"

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

var contNow = time.Date(2026, 8, 1, 12, 0, 0, 0, time.UTC)

func contSession(intent dialogue.Intent, key string) *dialogue.Session {
	return &dialogue.Session{
		Intent:    intent,
		Slots:     dialogue.Slots{Key: key, HasKey: key != "", Text: "какие напоминания на сегодня"},
		Timestamp: contNow.Add(-30 * time.Second),
		TTL:       2 * time.Minute,
	}
}

func TestContinuationInheritsTheQuestion(t *testing.T) {
	prev := contSession(dialogue.IntentQuery, "water")
	dec, ok := continuationDecision(prev, "а завтра?", contNow)
	if !ok {
		t.Fatal("continuationDecision returned false, want a decision")
	}
	if dec.Intent != router.IntentQuery {
		t.Errorf("intent = %q, want query", dec.Intent)
	}
	if dec.Slots.Key != "water" || !dec.Slots.HasKey {
		t.Errorf("key = %q, want water carried over", dec.Slots.Key)
	}
	if !dec.Slots.HasTime {
		t.Fatal("no time slot; the whole point is re-aiming the day")
	}
	if got, want := dec.Slots.Time.Format("2006-01-02"), "2026-08-02"; got != want {
		t.Errorf("time = %s, want %s", got, want)
	}
}

func TestContinuationAcceptsABareDate(t *testing.T) {
	prev := contSession(dialogue.IntentQuery, "water")
	for _, s := range []string{"завтра?", "вчера", "а вчера?", "и завтра"} {
		if _, ok := continuationDecision(prev, s, contNow); !ok {
			t.Errorf("continuationDecision(%q) = false, want true", s)
		}
	}
}

func TestContinuationDeclinesWhatIsNotAnEllipsis(t *testing.T) {
	prev := contSession(dialogue.IntentQuery, "water")
	for _, s := range []string{
		// No date to re-aim at — an ordinary short utterance, the router's job.
		"а что там", "а бэкап?", "привет", "",
		// Content of its own: the verb is not an ellipsis.
		"напомни завтра позвонить маме",
		// Too long to be an ellipsis even with a date in it.
		"а что у меня стоит в календаре на завтра",
	} {
		if _, ok := continuationDecision(prev, s, contNow); ok {
			t.Errorf("continuationDecision(%q) = true, want false", s)
		}
	}
}

func TestContinuationDeclinesUncontinuableIntents(t *testing.T) {
	// act is the one that matters: inheriting an allowlisted fn from a
	// two-word utterance would be a way to run a destructive command.
	// reminder is here because its payload is its Text, and the Text embeds
	// the day word it was created with — see continuableIntents.
	for _, in := range []dialogue.Intent{
		dialogue.IntentAct, dialogue.IntentFact, dialogue.IntentNote,
		dialogue.IntentChat, dialogue.IntentReminder,
	} {
		if _, ok := continuationDecision(contSession(in, "water"), "а завтра?", contNow); ok {
			t.Errorf("continuationDecision inherited intent %q, want refusal", in)
		}
	}
}

func TestContinuationDeclinesWithoutALiveSession(t *testing.T) {
	if _, ok := continuationDecision(nil, "а завтра?", contNow); ok {
		t.Error("continued with no previous turn")
	}
	stale := contSession(dialogue.IntentQuery, "water")
	stale.Timestamp = contNow.Add(-10 * time.Minute)
	if _, ok := continuationDecision(stale, "а завтра?", contNow); ok {
		t.Error("continued an expired session")
	}
}

func TestContinuationNeverCarriesAnFn(t *testing.T) {
	prev := contSession(dialogue.IntentQuery, "water")
	prev.Slots.Fn, prev.Slots.HasFn = "restart", true
	dec, ok := continuationDecision(prev, "а завтра?", contNow)
	if !ok {
		t.Fatal("want a decision")
	}
	if dec.Slots.HasFn || dec.Slots.Fn != "" {
		t.Fatalf("carried fn %q into a continuation", dec.Slots.Fn)
	}
}

// TestContinuationCarriesTheTopic — the ellipsis names the day; what he is
// asking ABOUT has to come from the previous turn, or replySystem keyword-
// matches "а завтра?" and finds nothing. Caught on the deployed daemon.
func TestContinuationCarriesTheTopic(t *testing.T) {
	prev := contSession(dialogue.IntentSystem, "")
	prev.Slots.Text = "какой сегодня день"
	dec, ok := continuationDecision(prev, "а завтра?", contNow)
	if !ok {
		t.Fatal("want a decision")
	}
	if dec.Slots.Text != "какой сегодня день" {
		t.Fatalf("Slots.Text = %q, want the previous turn's topic", dec.Slots.Text)
	}
}

// TestReplySystemIgnoresAnInheritedTopic — the regression the deployed daemon
// showed on 01-08-2026: followUpMerge fills an empty Text from the previous
// same-intent turn, so a plain "привет" after "какой сегодня день" arrived at
// replySystem carrying the old topic and was answered with the date. Only a
// continuation may widen the keyword match.
func TestReplySystemIgnoresAnInheritedTopic(t *testing.T) {
	h := &reactiveHandler{now: func() time.Time { return contNow }}
	inherited := router.Decision{
		Utterance: "привет",
		Intent:    router.IntentSystem,
		Slots:     router.Slots{Text: "какой сегодня день"},
	}
	if got := h.replySystem(nil, inherited); got != "пока не умею отвечать на этот вопрос." {
		t.Fatalf("replySystem answered %q on an inherited topic", got)
	}
	cont := inherited
	cont.Utterance, cont.Continued = "а завтра?", true
	if got := h.replySystem(nil, cont); got == "пока не умею отвечать на этот вопрос." {
		t.Fatalf("replySystem refused a real continuation")
	}
}

// TestRememberTurnRefreshesTheTopic — rememberTurn runs after followUpMerge,
// which has already inherited a Text from the previous same-intent turn. A
// fill-if-empty rule therefore pins the FIRST topic of a run of query turns
// and never lets go, so a later "а завтра?" continues a question two turns
// old. Seen on the deployed daemon, 01-08-2026.
func TestRememberTurnRefreshesTheTopic(t *testing.T) {
	h := &reactiveHandler{
		now:              func() time.Time { return contNow },
		dialogueSessions: dialogue.NewSessionStore(2 * time.Minute),
	}
	h.rememberTurn(nil, router.Decision{
		Intent: router.IntentQuery, Utterance: "во сколько у меня встреча",
	}, contNow)
	// The second turn arrives with the first turn's Text already merged in.
	prev := h.dialogueSessions.Get(voiceDialogueID, contNow)
	h.rememberTurn(prev, router.Decision{
		Intent:    router.IntentQuery,
		Utterance: "какие у меня планы",
		Slots:     router.Slots{Text: "во сколько у меня встреча"},
	}, contNow)
	got := h.dialogueSessions.Get(voiceDialogueID, contNow)
	if got == nil {
		t.Fatal("no session")
	}
	if got.Slots.Text != "какие у меня планы" {
		t.Fatalf("topic = %q, want the latest turn's", got.Slots.Text)
	}
}