package domain

import (
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"time"

	"git.cin.su/m/Assistant/contracts/authority"
	contract "git.cin.su/m/Assistant/contracts/continuity"
	"git.cin.su/m/Assistant/contracts/identity"
)

var ErrInvalidHumanResponse = errors.New("invalid human response")

type ResponseCandidate struct {
	Attention   contract.AttentionItem
	Prospective contract.ProspectiveItem
}

func InterpretHumanResponse(request contract.HumanResponseRequest, owner identity.PrincipalID, scope authority.ScopeID, id contract.HumanResponseID, candidates []ResponseCandidate, now time.Time) (contract.HumanResponseResult, error) {
	message := strings.TrimSpace(request.Message)
	if id == "" || owner == "" || scope == "" || request.SourceUtteranceID == "" || request.SourceIntentID == "" || message == "" || request.RequestedAtUnixMillis < 1 {
		return contract.HumanResponseResult{}, ErrInvalidHumanResponse
	}
	operation, snoozeUntil := detectResponseOperation(message, now)
	response := contract.HumanResponse{
		ID:                      id,
		OwnerPrincipalID:        owner,
		ScopeID:                 scope,
		SourceUtteranceID:       strings.TrimSpace(request.SourceUtteranceID),
		SourceIntentID:          strings.TrimSpace(request.SourceIntentID),
		Operation:               operation,
		TargetKind:              contract.ResponseTargetUnknown,
		ResolutionState:         contract.ResponseNoop,
		Outcome:                 contract.ResponseOutcomeNoop,
		SnoozeUntilUnixMillis:   snoozeUntil.UnixMilli(),
		RecordedAtUnixMillis:    now.UnixMilli(),
		Revision:                1,
		UserReportedNotVerified: false,
	}
	if operation == contract.ResponseUnknown {
		return contract.HumanResponseResult{Response: response, Handled: false}, nil
	}
	if len(candidates) == 0 {
		response.ResolutionState = contract.ResponseNoTarget
		response.Outcome = contract.ResponseOutcomeClarificationNeeded
		response.Clarification = "Я не вижу активного ожидания, к которому это относится."
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: response.Clarification}, nil
	}
	if len(candidates) > 1 {
		matched := matchingCandidates(message, candidates)
		if len(matched) == 1 {
			candidates = matched
		}
	}
	if len(candidates) > 1 {
		response.ResolutionState = contract.ResponseAmbiguous
		response.Outcome = contract.ResponseOutcomeClarificationNeeded
		response.Clarification = "У меня есть несколько возможных ожиданий. Уточните, о каком именно речь: " + candidateSummary(candidates)
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: response.Clarification}, nil
	}
	candidate := candidates[0]
	if candidate.Attention.ID != "" {
		response.TargetKind = contract.ResponseTargetAttentionItem
		response.TargetAttentionID = candidate.Attention.ID
		response.TargetProspectiveID = candidate.Attention.SourceProspectiveID
		response.TargetExternalRef = candidate.Attention.SourceExternalRef
	} else {
		response.TargetKind = contract.ResponseTargetProspectiveItem
		response.TargetProspectiveID = candidate.Prospective.ID
	}
	response.ResolutionState = contract.ResponseResolved
	if response.TargetExternalRef != "" && candidate.Attention.SourceKind == contract.AttentionSourceAgentDelegation {
		switch operation {
		case contract.ResponseContinue:
			response.Outcome = contract.ResponseOutcomeContinued
			return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Принял. Продолжаю работу по этой задаче."}, nil
		case contract.ResponseReject:
			response.Outcome = contract.ResponseOutcomeRejected
			return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Понял. Зафиксировал, что здесь нужно другое решение."}, nil
		}
	}
	switch operation {
	case contract.ResponseComplete:
		response.Outcome = contract.ResponseOutcomeUserReportedComplete
		response.UserReportedNotVerified = true
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Готово, я закрыл это напоминание. Записал как «сообщено человеком», без внешней проверки."}, nil
	case contract.ResponseSnooze:
		if response.SnoozeUntilUnixMillis <= now.UnixMilli() {
			response.ResolutionState = contract.ResponseNoop
			response.Outcome = contract.ResponseOutcomeClarificationNeeded
			response.Clarification = "На сколько отложить? Например: «Отложи на 10 минут»."
			return contract.HumanResponseResult{Response: response, Handled: true, Reply: response.Clarification}, nil
		}
		response.Outcome = contract.ResponseOutcomeSnoozed
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Отложил. Напомню " + humanResponseTime(snoozeUntil) + "."}, nil
	case contract.ResponseCancel:
		response.Outcome = contract.ResponseOutcomeCancelled
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Отменил. Больше не буду напоминать об этом."}, nil
	case contract.ResponseAcknowledge, contract.ResponseDismiss:
		response.Outcome = contract.ResponseOutcomeDismissed
		return contract.HumanResponseResult{Response: response, Handled: true, Reply: "Принял, убрал это из текущего внимания."}, nil
	default:
		response.ResolutionState = contract.ResponseNoop
		response.Outcome = contract.ResponseOutcomeNoop
		return contract.HumanResponseResult{Response: response, Handled: false}, nil
	}
}

func detectResponseOperation(message string, now time.Time) (contract.HumanResponseOperation, time.Time) {
	lower := strings.ToLower(strings.TrimSpace(message))
	if containsAny(lower, "отложи", "перенеси", "позже", "потом") {
		if until, ok := parseSnoozeUntil(lower, now); ok {
			return contract.ResponseSnooze, until
		}
		return contract.ResponseSnooze, time.Time{}
	}
	if containsAny(lower, "отмени", "отменить", "не надо", "не нужно", "больше не напоминай") {
		return contract.ResponseCancel, time.Time{}
	}
	if containsAny(lower, "готово", "сделал", "сделала", "выполнено", "закрыл", "закрыла") {
		return contract.ResponseComplete, time.Time{}
	}
	if lower == "ок" || lower == "понял" || lower == "поняла" || lower == "принято" {
		return contract.ResponseAcknowledge, time.Time{}
	}
	if containsAny(lower, "продолжай", "дальше") {
		return contract.ResponseContinue, time.Time{}
	}
	if containsAny(lower, "отклоняю", "нет", "не согласен", "не согласна") {
		return contract.ResponseReject, time.Time{}
	}
	return contract.ResponseUnknown, time.Time{}
}

func parseSnoozeUntil(lower string, now time.Time) (time.Time, bool) {
	relative := regexp.MustCompile(`(?:через|на)\s+(\d{1,3})\s*(минуту|минуты|минут|час|часа|часов)`)
	if match := relative.FindStringSubmatch(lower); len(match) > 0 {
		value, err := strconv.Atoi(match[1])
		if err != nil || value < 1 {
			return time.Time{}, false
		}
		if strings.HasPrefix(match[2], "час") {
			if value > 72 {
				return time.Time{}, false
			}
			return now.Add(time.Duration(value) * time.Hour), true
		}
		if value > 24*60 {
			return time.Time{}, false
		}
		return now.Add(time.Duration(value) * time.Minute), true
	}
	if strings.Contains(lower, "позже") || strings.Contains(lower, "потом") {
		return now.Add(time.Hour), true
	}
	return time.Time{}, false
}

func candidateSummary(candidates []ResponseCandidate) string {
	parts := make([]string, 0, len(candidates))
	for _, candidate := range candidates {
		text := strings.TrimSpace(candidate.Attention.Summary)
		if text == "" {
			text = strings.TrimSpace(candidate.Prospective.Summary)
		}
		if text == "" {
			text = "ожидание"
		}
		parts = append(parts, text)
	}
	if len(parts) > 3 {
		parts = parts[:3]
	}
	return strings.Join(parts, "; ")
}

func matchingCandidates(message string, candidates []ResponseCandidate) []ResponseCandidate {
	lower := strings.ToLower(message)
	var matched []ResponseCandidate
	for _, candidate := range candidates {
		summary := candidate.Attention.Summary
		if summary == "" {
			summary = candidate.Prospective.Summary
		}
		if summaryMatches(lower, summary) {
			matched = append(matched, candidate)
		}
	}
	return matched
}

func summaryMatches(lowerMessage string, summary string) bool {
	for _, token := range strings.Fields(strings.ToLower(summary)) {
		token = strings.Trim(token, ".,!?:;()[]«»\"'")
		if len([]rune(token)) < 4 {
			continue
		}
		if strings.Contains(lowerMessage, token) {
			return true
		}
	}
	return false
}

func humanResponseTime(value time.Time) string {
	if value.IsZero() {
		return "позже"
	}
	return fmt.Sprintf("%02d.%02d в %02d:%02d", value.Day(), value.Month(), value.Hour(), value.Minute())
}

func containsAny(value string, needles ...string) bool {
	for _, needle := range needles {
		if strings.Contains(value, needle) {
			return true
		}
	}
	return false
}