using System.Globalization;
using System.Text.Json;
using Deal.Contracts.Integrations.Abstractions;
using Deal.Contracts.Integrations.Models;
using Deal.Modules.Cards.Application.Models;
using Deal.Modules.Kanban.Application.Abstractions;
using Deal.Modules.Kanban.Application.Models;
using Deal.Modules.Kanban.Application.Services;
using Deal.Modules.Settings.Application.Abstractions;
using Deal.Modules.Settings.Application.Models;
// Алиас: статический класс ColumnRules лежит в одноимённом пространстве имён (см. CardsService) —
// внутри Deal.Modules.Kanban.Application имя ColumnRules резолвится в пространство.
using KanbanColumnRules = Deal.Modules.Kanban.Application.ColumnRules.ColumnRules;

namespace Deal.Infrastructure.Integrations.Services;

/// <summary>
/// Адаптер ИИ-предложений колонок/ключей — детерминированная эвристика.
/// </summary>
/// <param name="store">Порт хранилища (карточки «Неразобранного», переносы в колонки-доски).</param>
/// <param name="settings">KV-хранилище настроек тенанта.</param>
/// <param name="containersService">Сервис контейнеров: список существующих и создание suggested-колонок с дефолтами.</param>
public sealed class LocalColumnSuggester(
ICardStore store,
ISettingsStore settings,
ContainersService containersService) : IColumnSuggester
{

    private const long CooldownSeconds = 20 * 60;


    private const string CooldownReason = "недавно предлагали — подождите";

    private const string TooFewCardsReasonFormat = "мало карточек в «Неразобранном» (нужно от {0})";

    private const string NothingGroupedReason = "похожие колонки уже есть или нечего сгруппировать";

    private const string KeywordsTooFewReason = "мало карточек — сначала накопите заявки (нужно хотя бы 3)";

    private const string KeywordsEmptyReason = "ИИ не смог выделить ключи — попробуйте ещё раз";

    /// <inheritdoc />
    public async Task<SuggestColumnsResultDto> SuggestColumnsAsync(CancellationToken ct)
    {
        if (await WithinCooldownAsync(ct))
        {
            return new SuggestColumnsResultDto(Ok: false, Created: 0, Reason: CooldownReason, Cooldown: true);
        }

        IReadOnlyList<CardDto> inbox = await store.ListInboxWithSourceAsync(ct);
        if (inbox.Count < SuggestHeuristics.MinInbox)
        {
            return new SuggestColumnsResultDto(
                Ok: false,
                Created: 0,
                Reason: string.Format(TooFewCardsReasonFormat, SuggestHeuristics.MinInbox),
                Cooldown: false);
        }

        IReadOnlyList<ContainerDto> containers = await containersService.ListAsync(ContainerSpaces.Dashboard, ct);
        IReadOnlyList<string> existingNames = containers
            .Where(container => !container.Suggested)
            .Select(container => container.Name)
            .ToList();

        IReadOnlyList<SuggestedColumnPlan> plans = SuggestHeuristics.PlanColumns(inbox, existingNames);
        if (plans.Count == 0)
        {
            return new SuggestColumnsResultDto(Ok: false, Created: 0, Reason: NothingGroupedReason, Cooldown: false);
        }

        int created = await StoreSuggestedColumnsAsync(inbox, plans, ct);
        if (created == 0)
        {
            return new SuggestColumnsResultDto(Ok: false, Created: 0, Reason: NothingGroupedReason, Cooldown: false);
        }

        await WriteLastSuggestAtAsync(ct);
        return new SuggestColumnsResultDto(Ok: true, Created: created, Reason: null, Cooldown: false);
    }

    /// <inheritdoc />
    public async Task<SuggestKeywordsResultDto> SuggestKeywordsAsync(CancellationToken ct)
    {
        IReadOnlyList<CardDto> cards = await store.ListCardsAsync(new CardsQuery(null), ct);
        List<string> texts = cards
            .Where(card => card.Col != CardIds.Trash
                && card.Col != CardIds.Archive
                && (card.Content.Text ?? string.Empty).Trim().Length > 0)
            .Take(SuggestHeuristics.KeywordsSampleLimit)
            .Select(card => (card.Content.Text ?? string.Empty).Trim())
            .ToList();
        if (texts.Count < SuggestHeuristics.MinKeywordsSample)
        {
            return new SuggestKeywordsResultDto(Ok: false, Keywords: null, Reason: KeywordsTooFewReason);
        }

        IReadOnlyList<string> keywords = SuggestHeuristics.SuggestDomainKeywords(texts);
        if (keywords.Count == 0)
        {
            return new SuggestKeywordsResultDto(Ok: false, Keywords: null, Reason: KeywordsEmptyReason);
        }

        return new SuggestKeywordsResultDto(Ok: true, Keywords: keywords, Reason: null);
    }

    private async Task<int> StoreSuggestedColumnsAsync(
        IReadOnlyList<CardDto> inbox,
        IReadOnlyList<SuggestedColumnPlan> plans,
        CancellationToken ct)
    {
        HashSet<string> inboxIds = (await store.ListInboxWithSourceAsync(ct))
            .Select(card => card.Id)
            .ToHashSet(StringComparer.Ordinal);
        Dictionary<string, string> textByCardId = inbox
            .ToDictionary(card => card.Id, card => card.Content.Text ?? string.Empty, StringComparer.Ordinal);

        int created = 0;
        foreach (SuggestedColumnPlan plan in plans)
        {
            var rules = new ContainerRulesDto(
                Mode: ColumnRuleModes.Any,
                Direction: Array.Empty<string>(),
                Keywords: [plan.Word],
                Stack: Array.Empty<string>(),
                Grade: Array.Empty<string>(),
                Exclude: Array.Empty<string>(),
                Budget: null);
            ContainerDto container = await containersService.CreateAsync(new ContainerCreateDto(
                Name: plan.Name,
                Description: string.Empty,
                Color: null,
                Space: ContainerSpaces.Dashboard,
                Kind: ContainerKinds.Board,
                Suggested: true,
                Rules: rules,
                Note: plan.Note), ct);

            int placed = 0;
            foreach (string cardId in plan.CardIds)
            {
                if (!inboxIds.Contains(cardId))
                {
                    continue; // карточка уже разобрана другим предложением/пользователем (L231–233)
                }

                IReadOnlyList<MatchHitDto> hits = KanbanColumnRules.ComputeHits(rules, textByCardId[cardId]);
                await store.UpdateColumnAsync(new CardColumnUpdateDto(
                    CardId: cardId,
                    Col: container.Id,
                    IsNew: true,
                    PrevCol: CardIds.Inbox,
                    ArchivedAt: null,
                    MatchHits: hits), ct);
                placed++;
            }

            if (placed == 0)
            {
                await containersService.DeleteAsync(container.Id, ct);
                continue;
            }

            created++;
        }

        return created;
    }

    private async Task<bool> WithinCooldownAsync(CancellationToken ct)
    {
        SettingValue? row = await settings.GetAsync(SettingsKeys.LastSuggestAt, ct);
        if (row is null)
        {
            return false;
        }

        try
        {
            using JsonDocument document = JsonDocument.Parse(row.ValueJson);
            if (document.RootElement.ValueKind != JsonValueKind.Number)
            {
                return false;
            }

            long lastSuggestAt = document.RootElement.GetInt64();
            return DateTimeOffset.UtcNow.ToUnixTimeSeconds() - lastSuggestAt < CooldownSeconds;
        }
        catch (JsonException)
        {
            return false; // повреждённое значение не должно блокировать предложения
        }
    }

    private Task WriteLastSuggestAtAsync(CancellationToken ct) =>
        settings.SetAsync(
            SettingsKeys.LastSuggestAt,
            DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString(CultureInfo.InvariantCulture),
            ct);
}