package domain

import (
	"sort"
	"strings"

	"git.cin.su/m/Assistant/contracts/interaction"
)

// PersonalMemory is a rebuildable context projection. Its source of truth is
// the append-only human utterance history; it is deliberately not a second
// canonical store. Each fact retains the source utterance and confidence so a
// later cognitive or capability route can distinguish a human statement from
// an externally verified fact.
type PersonalMemory struct {
	Facts []PersonalMemoryFact
}

type PersonalMemoryFact struct {
	Kind                 string
	Value                string
	ConfidenceMillis     int64
	SourceUtteranceID    interaction.HumanUtteranceID
	ObservedAtUnixMillis int64
}

const personalMemoryCurrentLocation = "CURRENT_LOCATION"

// CompilePersonalMemory turns direct, first-person human statements into a
// small typed context. It deliberately preserves preferences as statements
// rather than pretending that an arbitrary preference is a verified fact.
func CompilePersonalMemory(history []interaction.HumanUtterance) PersonalMemory {
	latestLocation := PersonalMemoryFact{}
	preferences := make([]PersonalMemoryFact, 0, 4)
	for _, utterance := range history {
		if location := personalCurrentLocation(utterance.Content); location != "" {
			fact := PersonalMemoryFact{
				Kind:                 personalMemoryCurrentLocation,
				Value:                location,
				ConfidenceMillis:     950,
				SourceUtteranceID:    utterance.ID,
				ObservedAtUnixMillis: utterance.ReceivedAtUnixMillis,
			}
			if fact.ObservedAtUnixMillis >= latestLocation.ObservedAtUnixMillis {
				latestLocation = fact
			}
		}
		if preference := personalPreference(utterance.Content); preference != "" {
			preferences = append(preferences, PersonalMemoryFact{
				Kind:                 "PREFERENCE",
				Value:                preference,
				ConfidenceMillis:     900,
				SourceUtteranceID:    utterance.ID,
				ObservedAtUnixMillis: utterance.ReceivedAtUnixMillis,
			})
		}
	}
	result := PersonalMemory{Facts: make([]PersonalMemoryFact, 0, 1+len(preferences))}
	if latestLocation.Kind != "" {
		result.Facts = append(result.Facts, latestLocation)
	}
	sort.SliceStable(preferences, func(left, right int) bool {
		return preferences[left].ObservedAtUnixMillis > preferences[right].ObservedAtUnixMillis
	})
	if len(preferences) > 8 {
		preferences = preferences[:8]
	}
	result.Facts = append(result.Facts, preferences...)
	return result
}

func (m PersonalMemory) CurrentLocation() string {
	for _, fact := range m.Facts {
		if fact.Kind == personalMemoryCurrentLocation {
			return fact.Value
		}
	}
	return ""
}

// ContextText is compact, source-aware context for a cognitive or skill
// request. It contains facts rather than a copied chat transcript.
func (m PersonalMemory) ContextText() string {
	lines := make([]string, 0, len(m.Facts))
	for _, fact := range m.Facts {
		value := strings.TrimSpace(fact.Value)
		if value == "" {
			continue
		}
		switch fact.Kind {
		case personalMemoryCurrentLocation:
			lines = append(lines, "Текущее место пользователя (его сообщение): "+value)
		case "PREFERENCE":
			lines = append(lines, "Предпочтение пользователя (его сообщение): "+value)
		}
	}
	return strings.Join(lines, "\n")
}

func personalCurrentLocation(message string) string {
	tokens := semanticTokens(message)
	if len(tokens) < 4 || tokens[0] != "я" || !containsStemInTokens(tokens, "сейчас", "нахож", "жив") {
		return ""
	}
	for index, token := range tokens {
		if (token == "в" || token == "на") && index+1 < len(tokens) {
			return capitalizeWord(tokens[index+1])
		}
	}
	return ""
}

func personalPreference(message string) string {
	lower := strings.ToLower(strings.TrimSpace(message))
	for _, cue := range []string{"мне нравится", "я люблю"} {
		index := strings.Index(lower, cue)
		if index < 0 {
			continue
		}
		value := strings.TrimSpace(lower[index+len(cue):])
		value = strings.Trim(value, " .,!?:;—-")
		if len([]rune(value)) >= 2 {
			return value
		}
	}
	return ""
}