package domain

import (
	"strings"
	"time"

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

// TravelSearchQuery carries the implicit current-day meaning of a nearest
// flight request into the research adapter.
func TravelSearchQuery(message string, now time.Time) string {
	cleaned := normalizedTravelSearchText(message)
	tokens := semanticTokens(cleaned)
	if !travelCue(tokens) || !containsStemInTokens(tokens, "ближ") || isTravelDateSpecified(tokens) {
		return cleaned
	}
	if now.IsZero() {
		return cleaned + " сегодня"
	}
	return cleaned + " сегодня " + now.Format("02.01.2006")
}

// normalizedTravelSearchText corrects only a near-unambiguous typo in a
// capability word before an external query. The original utterance is kept by
// Conversation; this is a replaceable search-skill normalization, not a fact
// about a user, city or provider.
func normalizedTravelSearchText(message string) string {
	tokens := semanticTokens(StripAssistantVocative(message))
	changed := false
	for index, token := range tokens {
		if nearToken(token, "самолет", 2) || nearToken(token, "самолёт", 2) {
			tokens[index] = "самолёт"
			changed = true
		}
	}
	if !changed {
		return strings.TrimSpace(StripAssistantVocative(message))
	}
	return strings.Join(tokens, " ")
}

// TravelResearchQuery keeps route and distance questions tied to a known
// origin before they reach a generic web search. The history is semantic
// context, not a list of example-specific answers.
func TravelResearchQuery(message string, history []interaction.HumanUtterance, now time.Time) string {
	query := TravelSearchQuery(message, now)
	tokens := semanticTokens(StripAssistantVocative(message))
	if localPlaceSearchRequest(tokens) {
		return localPlaceResearchQuery(tokens)
	} else if containsStemInTokens(tokens, "расстоян", "километр") {
		origin := travelContextOrigin(history)
		destination := travelContextDestinationFromTokens(tokens)
		if origin != "" && destination != "" {
			return "расстояние между " + origin + " и " + destination + " в километрах по прямой и по дороге"
		}
		if origin != "" && !containsStemInTokens(tokens, "из", "откуда", "от") {
			query += " точка отправления: " + origin
		}
		query += " расстояние по прямой и по дороге"
	} else if containsStemInTokens(tokens, "добрат", "маршрут") {
		origin := travelContextOrigin(history)
		destination := travelContextDestinationFromTokens(tokens)
		if origin != "" && destination != "" {
			return "способы добраться из " + origin + " в " + destination + ": самолет поезд автобус автомобиль"
		}
		if origin != "" && !containsStemInTokens(tokens, "из", "откуда", "от") {
			query += " отправление из " + origin
		}
	} else if trainScheduleRequest(tokens) {
		origin := travelContextOrigin(history)
		destination := travelContextDestinationFromTokens(tokens)
		if origin != "" && destination != "" {
			return trainScheduleResearchQuery(origin, destination, now, containsStemInTokens(tokens, "ближ"))
		}
	} else if travelCue(tokens) && !containsStemInTokens(tokens, "из", "откуда", "от") {
		origin := travelContextOrigin(history)
		destination := travelContextDestinationFromTokens(tokens)
		if nearestAirTravelRequest(tokens) && origin != "" && destination != "" {
			return nearestAirTravelSearchQuery(origin, destination, now)
		}
		if origin != "" {
			// Preserve the remembered location as an explicit search parameter
			// instead of guessing its grammatical form in the user's language.
			query += " пункт отправления: " + origin
		}
	}
	return query
}

// localPlaceSearchRequest recognizes a proximity search as a local-search
// capability, keeping it separate from travel-route compilation.
func localPlaceSearchRequest(tokens []string) bool {
	return containsStemInTokens(tokens, "ресторан", "кафе") && containsStemInTokens(tokens, "ближ", "рядом")
}

func localPlaceResearchQuery(tokens []string) string {
	parts := make([]string, 0, len(tokens))
	for _, token := range tokens {
		if containsStem(token, "найд", "покаж", "ближ", "рядом") {
			continue
		}
		parts = append(parts, token)
	}
	return "места " + strings.Join(parts, " ") + " адрес отзывы меню"
}

// trainScheduleResearchQuery formulates an observed schedule request from the
// user's route and remembered origin. It contains no city, provider or answer
// catalogue: actual departure data remains evidence from the selected source.
func trainScheduleResearchQuery(origin, destination string, now time.Time, nearest bool) string {
	prefix := "расписание поездов"
	if nearest {
		prefix = "ближайшие поезда"
	}
	query := prefix + " из " + origin + " в " + destination + " время отправления"
	if !now.IsZero() {
		query += " сегодня " + now.Format("02.01.2006")
	}
	return query
}

// nearestAirTravelSearchQuery is a capability-local search formulation, not a
// provider or place lookup. It removes conversational imperatives while
// preserving the two user-derived route endpoints and the implicit current-day
// meaning of "ближайший".
func nearestAirTravelSearchQuery(origin, destination string, now time.Time) string {
	query := "ближайшие авиарейсы " + origin + " " + destination + " сегодня"
	if !now.IsZero() {
		query += " " + now.Format("02.01.2006")
	}
	return query
}

// StripAssistantVocative removes a leading assistant name used as an address.
// The original utterance remains the historical source; this value is only for
// interpretation, cognitive prompts and external queries.
func StripAssistantVocative(message string) string {
	trimmed := strings.TrimSpace(message)
	lower := strings.ToLower(trimmed)
	for _, name := range []string{"дед", "домовой"} {
		if !strings.HasPrefix(lower, name) {
			continue
		}
		rest := trimmed[len(name):]
		if rest == "" || !strings.ContainsRune(" \t,;:!?—-", []rune(rest)[0]) {
			continue
		}
		return strings.TrimSpace(strings.TrimLeft(rest, " \t,;:!?—-"))
	}
	return trimmed
}

// IndependentRequestParts keeps separate user actions visible to the
// orchestrator. It is intentionally limited to the ordinary coordinating
// conjunction; the cognitive route remains responsible for ambiguous prose.
func IndependentRequestParts(message string) []string {
	cleaned := StripAssistantVocative(message)
	if containsToken(semanticTokens(cleaned), "между") {
		return []string{cleaned}
	}
	parts := strings.Split(cleaned, " и ")
	if len(parts) < 2 {
		return []string{cleaned}
	}
	result := make([]string, 0, len(parts))
	for _, part := range parts {
		part = strings.TrimSpace(part)
		if part != "" {
			result = append(result, part)
		}
	}
	if len(result) < 2 {
		return []string{cleaned}
	}
	return result
}

// LocalSearchClarification prevents a proximity search from silently using a
// default city when the user did not provide a place.
func LocalSearchClarification(message string) string {
	tokens := semanticTokens(StripAssistantVocative(message))
	if !containsStemInTokens(tokens, "ресторан", "кафе") || !containsStemInTokens(tokens, "ближ", "рядом") {
		return ""
	}
	for index, token := range tokens {
		if token != "в" && token != "на" && token != "около" && !containsStem(token, "район", "город") {
			continue
		}
		if index+1 < len(tokens) || containsStem(token, "район", "город") {
			return ""
		}
	}
	return "В каком городе или районе искать ресторан?"
}

// ContinueLocalSearch turns a location-only follow-up into the previous local
// search request, but only when that request is present in this conversation.
func ContinueLocalSearch(message string, history []interaction.HumanUtterance) string {
	current := strings.TrimSpace(StripAssistantVocative(message))
	tokens := semanticTokens(current)
	if len(tokens) == 0 || len(tokens) > 3 || (tokens[0] != "в" && tokens[0] != "на" && tokens[0] != "около") {
		return ""
	}
	var latest *interaction.HumanUtterance
	for index := range history {
		candidate := history[index]
		candidateText := strings.TrimSpace(StripAssistantVocative(candidate.Content))
		candidateTokens := semanticTokens(candidateText)
		if !containsStemInTokens(candidateTokens, "ресторан", "кафе") || !containsStemInTokens(candidateTokens, "ближ", "рядом") {
			continue
		}
		if latest == nil || candidate.ReceivedAtUnixMillis > latest.ReceivedAtUnixMillis {
			latest = &candidate
		}
	}
	if latest != nil {
		previous := strings.TrimSpace(StripAssistantVocative(latest.Content))
		return strings.TrimSpace(previous + " " + current)
	}
	return ""
}

// ContinueTravelOrigin turns a short location answer into the previous travel
// task. The original utterance remains history; only the effective task is
// completed for routing and research.
func ContinueTravelOrigin(message string, history []interaction.HumanUtterance) string {
	current := semanticTokens(StripAssistantVocative(message))
	if len(current) == 0 || len(current) > 6 {
		return ""
	}
	location := ""
	if current[0] == "я" {
		if len(current) < 3 {
			return ""
		}
		for index, token := range current {
			if (token == "в" || token == "из") && index+1 < len(current) {
				location = capitalizeWord(current[index+1])
				break
			}
		}
	} else if len(current) <= 2 && !isTravelDateWord(current[0]) && len([]rune(current[0])) >= 3 {
		location = capitalizeWord(current[0])
	}
	if location == "" {
		return ""
	}
	var latest *interaction.HumanUtterance
	for index := range history {
		candidate := history[index]
		if !travelContextCue(semanticTokens(candidate.Content)) {
			continue
		}
		if latest == nil || candidate.ReceivedAtUnixMillis > latest.ReceivedAtUnixMillis {
			latest = &candidate
		}
	}
	if latest == nil {
		return ""
	}
	previous := strings.TrimRight(strings.TrimSpace(StripAssistantVocative(latest.Content)), "?!.,;:")
	preposition := " из "
	if current[0] != "я" {
		preposition = " из города "
	}
	return strings.TrimSpace(previous + preposition + location)
}

// ContinueTravelDate completes the most recent unfinished ticket search with
// a short date answer. The date is still the human's original wording, so the
// later route and research stages retain its provenance and can interpret it
// relative to the current time.
func ContinueTravelDate(message string, history []interaction.HumanUtterance) string {
	current := strings.TrimSpace(StripAssistantVocative(message))
	currentTokens := semanticTokens(current)
	if len(currentTokens) == 0 || len(currentTokens) > 6 || !isTravelDateSpecified(currentTokens) {
		return ""
	}
	latestAt := int64(-1)
	latest := ""
	for _, utterance := range history {
		tokens := semanticTokens(utterance.Content)
		if !travelCue(tokens) || isTravelDateSpecified(tokens) || containsStemInTokens(tokens, "ближ") {
			continue
		}
		if utterance.ReceivedAtUnixMillis >= latestAt {
			latestAt = utterance.ReceivedAtUnixMillis
			latest = strings.TrimSpace(StripAssistantVocative(utterance.Content))
		}
	}
	if latest == "" {
		return ""
	}
	return strings.TrimSpace(latest + " " + current)
}

// TicketSearchDestination extracts the destination from a ticket request
// without assigning any city or travel-provider meaning in core code.
func TicketSearchDestination(message string) string {
	tokens := semanticTokens(StripAssistantVocative(message))
	if !containsStemInTokens(tokens, "билет") {
		return ""
	}
	return travelContextDestinationFromTokens(tokens)
}

// TravelSearchClarification keeps an incomplete travel request in dialogue
// instead of reducing it to an unrelated generic web search.
func TravelSearchClarification(message string, history []interaction.HumanUtterance) string {
	current := semanticTokens(StripAssistantVocative(message))
	travel := travelCue(current)
	if !travel {
		travel = containsStemInTokens(current, "добрат", "передвиг", "поех", "дорог")
	}
	if !travel && travelFollowUpCue(current) {
		for index := len(history) - 1; index >= 0; index-- {
			if travelCue(semanticTokens(history[index].Content)) {
				travel = true
				break
			}
		}
	}
	if !travel {
		return ""
	}
	origin := containsStemInTokens(current, "из", "откуда", "от")
	destination := containsStemInTokens(current, "в", "куда", "до")
	date := isTravelDateSpecified(current)
	if containsStemInTokens(current, "ближ") {
		date = true
	}
	if !date {
		for _, token := range current {
			if hasDigit(token) {
				date = true
				break
			}
		}
	}
	ticketRequest := containsStemInTokens(current, "билет", "рейс", "самолет", "самолёт", "вылет")
	if !destination {
		if contextDestination := travelContextDestination(history); contextDestination != "" {
			destination = true
			if !origin && !date {
				return "Из какого города вылетать в " + contextDestination + " и на какую дату?"
			}
			if !origin {
				return "Из какого города вылетать в " + contextDestination + "?"
			}
		}
	}
	if !origin {
		if contextOrigin := travelContextOrigin(history); contextOrigin != "" {
			origin = true
		}
	}
	if origin && destination && (date || !ticketRequest) {
		return ""
	}
	if destination && !origin && !date {
		if !ticketRequest {
			return "Из какого города выезжать в " + destinationLabel(current, history) + "? Подберу самолёт, поезд, автобус или машину."
		}
		return "Из какого города вылетать и на какую дату?"
	}
	if destination && !origin {
		return "Из какого города вылетать?"
	}
	if destination && !date {
		if !ticketRequest {
			return ""
		}
		return "На какую дату нужны билеты?"
	}
	return "Уточните маршрут и дату: откуда, куда и на какой день нужны билеты?"
}

func isTravelDateSpecified(tokens []string) bool {
	if containsStemInTokens(tokens, "сегодня", "завтра", "послезавтр", "январ", "феврал", "март", "апрел", "мая", "июн", "июл", "август", "сентябр", "октябр", "ноябр", "декабр") {
		return true
	}
	for _, token := range tokens {
		if hasDigit(token) {
			return true
		}
	}
	return false
}

func isTravelDateWord(value string) bool {
	return containsStem(value, "сегодня", "завтра", "послезавтр", "январ", "феврал", "март", "апрел", "мая", "июн", "июл", "август", "сентябр", "октябр", "ноябр", "декабр")
}

func destinationLabel(current []string, history []interaction.HumanUtterance) string {
	for index, token := range current {
		if (token == "в" || token == "до") && index+1 < len(current) {
			return capitalizeWord(current[index+1])
		}
	}
	if destination := travelContextDestination(history); destination != "" {
		return destination
	}
	return "пункт назначения"
}

func travelContextDestinationFromTokens(tokens []string) string {
	for index, token := range tokens {
		if token != "до" && token != "в" && token != "к" {
			continue
		}
		if index+1 < len(tokens) && len([]rune(tokens[index+1])) >= 3 {
			return capitalizeWord(tokens[index+1])
		}
	}
	return ""
}

func travelContextDestination(history []interaction.HumanUtterance) string {
	latestAt := int64(-1)
	latest := ""
	for _, utterance := range history {
		tokens := semanticTokens(utterance.Content)
		if !travelContextCue(tokens) {
			continue
		}
		for tokenIndex, token := range tokens {
			if token != "в" && token != "до" {
				continue
			}
			if tokenIndex+1 < len(tokens) && len([]rune(tokens[tokenIndex+1])) >= 3 {
				if utterance.ReceivedAtUnixMillis >= latestAt {
					latestAt = utterance.ReceivedAtUnixMillis
					latest = capitalizeWord(tokens[tokenIndex+1])
				}
				break
			}
		}
	}
	return latest
}

func travelContextOrigin(history []interaction.HumanUtterance) string {
	return CompilePersonalMemory(history).CurrentLocation()
}

func travelContextCue(tokens []string) bool {
	return travelCue(tokens) || containsStemInTokens(tokens, "добрат", "передвиг", "ехать", "едем", "лететь", "поездк")
}

func capitalizeWord(value string) string {
	runes := []rune(value)
	if len(runes) == 0 {
		return value
	}
	return strings.ToUpper(string(runes[0])) + string(runes[1:])
}

func travelCue(tokens []string) bool {
	return containsStemInTokens(tokens, "билет", "рейс", "самолет", "самолёт", "вылет", "поезд", "автобус", "перелет", "перелёт") || approximateToken(tokens, "самолет", 2) || approximateToken(tokens, "самолёт", 2)
}

func trainScheduleRequest(tokens []string) bool {
	return containsStemInTokens(tokens, "поезд") &&
		(containsStemInTokens(tokens, "найд", "ближ", "расписан", "отправ", "прибуд", "едет", "едут") || len(tokens) > 1)
}

func nearestAirTravelRequest(tokens []string) bool {
	return containsStemInTokens(tokens, "ближ") && containsStemInTokens(tokens, "самолет", "самолёт", "авиарейс", "перелет", "перелёт")
}

func travelFollowUpCue(tokens []string) bool {
	return containsStemInTokens(tokens, "куда", "откуда", "маршрут", "летим", "дата", "число")
}

func hasDigit(value string) bool {
	for _, runeValue := range value {
		if runeValue >= '0' && runeValue <= '9' {
			return true
		}
	}
	return false
}