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.
	for _, in := range []dialogue.Intent{
		dialogue.IntentAct, dialogue.IntentFact, dialogue.IntentNote, dialogue.IntentChat,
	} {
		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)
	}
}