package main

import (
	"time"

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

// voiceDialogueID — the single dialogue-session key. This is a single-user box
// (ponytail), so one slot suffices; a second speaker would need per-speaker ids,
// which waits on voice-print attribution (see PROGRESS multi-user deferral).
const voiceDialogueID = "voice"

// toDialogueSlots projects the router's slots onto the dialogue layer's subset
// (everything except the fact Value, which the dialogue layer doesn't carry).
func toDialogueSlots(s router.Slots) dialogue.Slots {
	return dialogue.Slots{
		Time:    s.Time,
		HasTime: s.HasTime,
		Key:     s.Key,
		HasKey:  s.HasKey,
		Text:    s.Text,
		Fn:      s.Fn,
		Args:    s.Args,
		HasFn:   s.HasFn,
	}
}

// applyDialogueSlots writes inherited dialogue slots back onto router slots,
// preserving router-only fields (Value) the dialogue layer never touched.
func applyDialogueSlots(base router.Slots, d dialogue.Slots) router.Slots {
	base.Time, base.HasTime = d.Time, d.HasTime
	base.Key, base.HasKey = d.Key, d.HasKey
	base.Text = d.Text
	base.Fn, base.Args, base.HasFn = d.Fn, d.Args, d.HasFn
	return base
}

// followUpMerge fills the current turn's missing slots from a prior same-intent,
// non-expired session — the multi-turn seam. A different intent is a fresh
// command, not a follow-up, so it's returned untouched; a clarify turn resolved
// nothing, so it never inherits. InheritSlots only fills gaps, so a fully-slotted
// current turn is unaffected.
func followUpMerge(prev *dialogue.Session, dec router.Decision, now time.Time) router.Decision {
	if prev == nil || dec.Clarify || prev.IsExpired(now) {
		return dec
	}
	if prev.Intent != dialogue.Intent(dec.Intent) {
		return dec
	}
	merged := dialogue.InheritSlots(prev.Slots, toDialogueSlots(dec.Slots))
	dec.Slots = applyDialogueSlots(dec.Slots, merged)
	return dec
}