using System;
using System.Linq;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.UI;
using Vanguard.Api;
using Vanguard.Api.Contracts;
using Vanguard.Auth;
using Vanguard.Meta;

namespace Vanguard.UI
{
    /// <summary>Первый вход: выбор одной из двух бесплатных триал-дек.</summary>
    public sealed class OnboardingView
    {
        private readonly AuthService _auth;
        private readonly MetaService _meta;
        private readonly Action _onCompleted;
        private readonly Action _onLoggedOut;

        private readonly RectTransform _root;
        private readonly RectTransform _deckRow;
        private readonly Text _status;
        private readonly Button _retry;
        private readonly Button _logout;
        private bool _loading;

        public OnboardingView(
            Transform parent,
            AuthService auth,
            MetaService meta,
            Action onCompleted,
            Action onLoggedOut)
        {
            _auth = auth;
            _meta = meta;
            _onCompleted = onCompleted;
            _onLoggedOut = onLoggedOut;

            _root = UiKit.CreatePanel(parent, "OnboardingScreen", new Color(0.035f, 0.045f, 0.065f, 1f));
            var card = UiKit.CreateCenteredCard(
                _root,
                "OnboardingCard",
                new Vector2(1320f, 900f),
                new Color(0.07f, 0.085f, 0.115f, 1f));
            UiKit.AddVerticalLayout(card, 34, 12);

            var title = UiKit.CreateText(
                card, "Title", "Стартовый набор", 46, Color.white);
            title.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(title, 58f);

            var subtitle = UiKit.CreateText(
                card,
                "Subtitle",
                "Выберите одну триал-деку. 50 карт попадут в коллекцию, плюс 5 токенов на бустеры.",
                20,
                new Color(0.68f, 0.74f, 0.88f));
            UiKit.SetPreferredHeight(subtitle, 54f);

            _deckRow = UiKit.CreatePanel(
                card,
                "DeckRow",
                new Color(0.05f, 0.06f, 0.085f, 1f));
            UiKit.SetPreferredHeight(_deckRow, 500f);
            UiKit.AddHorizontalLayout(_deckRow, 16, 18);

            _status = UiKit.CreateText(
                card, "Status", string.Empty, 18,
                new Color(0.68f, 0.74f, 0.88f),
                TextAnchor.MiddleCenter);
            UiKit.SetPreferredHeight(_status, 38f);

            _retry = UiKit.CreateButton(card, "Retry", "Повторить загрузку", OnRetryClicked, 18);
            UiKit.SetPreferredHeight(_retry, 42f);
            _retry.gameObject.SetActive(false);

            _logout = UiKit.CreateButton(card, "Logout", "Выйти из аккаунта", OnLogoutClicked, 18);
            UiKit.SetPreferredHeight(_logout, 42f);

            _root.gameObject.SetActive(false);
        }

        public void Show()
        {
            UiKit.SetActive(_root, true);
            _ = LoadAsync();
        }

        public void Hide() => UiKit.SetActive(_root, false);

        private async Task LoadAsync()
        {
            if (_loading)
                return;

            _loading = true;
            _retry.gameObject.SetActive(false);
            _logout.interactable = false;
            ClearDeckRow();
            SetStatus("Загружаем триал-деки…", new Color(0.68f, 0.74f, 0.88f));

            try
            {
                var store = await _meta.GetStoreAsync();
                BuildDecks(store);
                SetStatus("Выберите деку — выбор делается один раз.", new Color(0.68f, 0.74f, 0.88f));
            }
            catch (ApiException exception)
            {
                SetStatus(exception.Message, new Color(1f, 0.55f, 0.45f));
                _retry.gameObject.SetActive(true);
            }
            catch (Exception exception)
            {
                Debug.LogException(exception);
                SetStatus("Не удалось загрузить триал-деки. Сервер недоступен?", new Color(1f, 0.55f, 0.45f));
                _retry.gameObject.SetActive(true);
            }
            finally
            {
                _loading = false;
                _logout.interactable = true;
            }
        }

        private void BuildDecks(StoreResponse store)
        {
            if (store.TrialDecks == null || store.TrialDecks.Count == 0)
            {
                SetStatus("Сервер не вернул ни одной триал-деки.", new Color(1f, 0.55f, 0.45f));
                return;
            }

            foreach (var deck in store.TrialDecks)
                BuildDeck(deck);
        }

        private void BuildDeck(StoreTrialDeckDto deck)
        {
            var card = UiKit.CreatePanel(
                _deckRow,
                "Trial_" + deck.Id,
                new Color(0.09f, 0.11f, 0.15f, 1f));
            var element = card.gameObject.AddComponent<LayoutElement>();
            element.flexibleWidth = 1f;
            element.preferredHeight = 460f;
            UiKit.AddVerticalLayout(card, 24, 10);

            var name = UiKit.CreateText(card, "Name", deck.Name, 30, Color.white, TextAnchor.MiddleLeft);
            UiKit.MakeLiteral(name);
            name.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(name, 42f);

            var clan = UiKit.CreateText(
                card, "Clan", "Клан: " + (string.IsNullOrEmpty(deck.Clan) ? "—" : deck.Clan),
                20, new Color(0.68f, 0.74f, 0.88f), TextAnchor.MiddleLeft);
            UiKit.SetPreferredHeight(clan, 30f);

            var count = UiKit.CreateText(
                card, "Count", deck.CardCount + " карт · " + deck.Cards.Count + " уникальных",
                18, new Color(0.60f, 0.67f, 0.80f), TextAnchor.MiddleLeft);
            UiKit.SetPreferredHeight(count, 28f);

            var preview = UiKit.CreateText(
                card,
                "Preview",
                BuildPreview(deck),
                16,
                new Color(0.52f, 0.60f, 0.74f),
                TextAnchor.UpperLeft);
            preview.horizontalOverflow = HorizontalWrapMode.Wrap;
            UiKit.SetPreferredHeight(preview, 150f, 1f);

            if (deck.Owned)
            {
                var owned = UiKit.CreateText(
                    card, "Owned", "Уже в коллекции", 18,
                    new Color(0.45f, 0.85f, 0.55f));
                UiKit.SetPreferredHeight(owned, 28f);
            }

            var choose = UiKit.CreateButton(
                card,
                "Choose",
                deck.Owned ? "Дека уже получена" : "Выбрать бесплатно",
                () => OnChooseClicked(deck),
                21);
            choose.interactable = !deck.Owned;
            UiKit.SetPreferredHeight(choose, 54f);
        }

        private static string BuildPreview(StoreTrialDeckDto deck)
        {
            if (deck.Cards == null || deck.Cards.Count == 0)
                return "Состав появится после выбора.";

            var lines = deck.Cards
                .Take(8)
                .Select(card => "• " + card.PrintingId + " ×" + card.Count);

            return string.Join("\n", lines);
        }

        private async void OnChooseClicked(StoreTrialDeckDto deck)
        {
            if (_loading)
                return;

            _loading = true;
            _retry.gameObject.SetActive(false);
            SetStatus("Активируем " + deck.Name + "…", new Color(0.68f, 0.74f, 0.88f));

            try
            {
                await _meta.OnboardAsync(deck.Id);
                _onCompleted();
            }
            catch (ApiException exception)
            {
                SetStatus(exception.Message, new Color(1f, 0.55f, 0.45f));
            }
            catch (Exception exception)
            {
                Debug.LogException(exception);
                SetStatus("Не удалось завершить онбординг.", new Color(1f, 0.55f, 0.45f));
            }
            finally
            {
                _loading = false;
            }
        }

        private void OnRetryClicked()
        {
            _ = LoadAsync();
        }

        private async void OnLogoutClicked()
        {
            _logout.interactable = false;
            await _auth.LogoutAsync();
            _onLoggedOut();
        }

        private void ClearDeckRow()
        {
            for (var i = _deckRow.childCount - 1; i >= 0; i--)
                UnityEngine.Object.Destroy(_deckRow.GetChild(i).gameObject);
        }

        private void SetStatus(string text, Color color)
        {
            _status.text = text ?? string.Empty;
            _status.color = color;
        }
    }
}