package main

import (
	"testing"
	"time"

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

func TestFollowUpMerge(t *testing.T) {
	base := time.Date(2026, 7, 6, 12, 0, 0, 0, time.UTC)
	fireAt := base.Add(24 * time.Hour)

	// prior turn: a reminder that resolved a fire time.
	prev := &dialogue.Session{
		Intent:    dialogue.IntentReminder,
		Slots:     dialogue.Slots{Time: fireAt, HasTime: true, Text: "старый текст"},
		Timestamp: base,
		TTL:       2 * time.Minute,
	}

	t.Run("same intent inherits the missing time", func(t *testing.T) {
		// follow-up reminder with text but no parsed time.
		cur := router.Decision{
			Intent: router.IntentReminder,
			Slots:  router.Slots{Text: "позвонить маме"},
		}
		got := followUpMerge(prev, cur, base.Add(30*time.Second))
		if !got.Slots.HasTime || !got.Slots.Time.Equal(fireAt) {
			t.Errorf("time not inherited: HasTime=%v Time=%v", got.Slots.HasTime, got.Slots.Time)
		}
		if got.Slots.Text != "позвонить маме" {
			t.Errorf("current text was overwritten: %q", got.Slots.Text)
		}
	})

	t.Run("current slot wins over prior (gaps only)", func(t *testing.T) {
		own := base.Add(48 * time.Hour)
		cur := router.Decision{
			Intent: router.IntentReminder,
			Slots:  router.Slots{Time: own, HasTime: true},
		}
		got := followUpMerge(prev, cur, base.Add(30*time.Second))
		if !got.Slots.Time.Equal(own) {
			t.Errorf("current time clobbered by prior: %v", got.Slots.Time)
		}
	})

	t.Run("different intent does not inherit", func(t *testing.T) {
		cur := router.Decision{Intent: router.IntentFact, Slots: router.Slots{Key: "water", HasKey: true}}
		got := followUpMerge(prev, cur, base.Add(30*time.Second))
		if got.Slots.HasTime {
			t.Error("time bled across a different intent")
		}
	})

	t.Run("clarify turn does not inherit", func(t *testing.T) {
		cur := router.Decision{Intent: router.IntentReminder, Clarify: true}
		got := followUpMerge(prev, cur, base.Add(30*time.Second))
		if got.Slots.HasTime {
			t.Error("clarify turn inherited slots")
		}
	})

	t.Run("expired prior does not inherit", func(t *testing.T) {
		cur := router.Decision{Intent: router.IntentReminder, Slots: router.Slots{Text: "x"}}
		got := followUpMerge(prev, cur, base.Add(3*time.Minute)) // past the 2-min TTL
		if got.Slots.HasTime {
			t.Error("expired session still inherited")
		}
	})

	t.Run("nil prior is a no-op", func(t *testing.T) {
		cur := router.Decision{Intent: router.IntentReminder, Slots: router.Slots{Text: "x"}}
		got := followUpMerge(nil, cur, base)
		if got.Slots.HasTime {
			t.Error("nil prior produced inheritance")
		}
	})

	t.Run("router-only Value survives the round-trip", func(t *testing.T) {
		cur := router.Decision{
			Intent: router.IntentFact,
			Slots:  router.Slots{Key: "sleep", HasKey: true, Value: "6h"},
		}
		factPrev := &dialogue.Session{
			Intent:    dialogue.IntentFact,
			Slots:     dialogue.Slots{Text: "спал"},
			Timestamp: base,
			TTL:       2 * time.Minute,
		}
		got := followUpMerge(factPrev, cur, base.Add(10*time.Second))
		if got.Slots.Value != "6h" {
			t.Errorf("Value lost through dialogue conversion: %q", got.Slots.Value)
		}
	})
}