using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.UI;
using Vanguard.Api;
using Vanguard.Api.Contracts;
using Vanguard.Meta;
using Vanguard.State;

namespace Vanguard.UI
{
    /// <summary>Коллекция игрока и разбор карт в пыль.</summary>
    public sealed class CollectionView : IDisposable
    {
        private readonly MetaService _meta;
        private readonly PlayerState _player;
        private readonly Action _onBack;
        private bool _disposed;

        private readonly RectTransform _root;
        private readonly Text _balances;
        private readonly Text _status;
        private readonly RectTransform _confirm;
        private Text _confirmText;
        private RectTransform _content;
        private CollectionItemDto _pending;
        private bool _loading;

        public CollectionView(
            Transform parent,
            MetaService meta,
            PlayerState player,
            Action onBack)
        {
            _meta = meta;
            _player = player;
            _onBack = onBack;

            _root = UiKit.CreatePanel(parent, "CollectionScreen", new Color(0.035f, 0.045f, 0.065f, 1f));

            var top = UiKit.CreatePanel(_root, "TopBar", new Color(0.07f, 0.085f, 0.115f, 1f));
            top.anchorMin = new Vector2(0f, 1f);
            top.anchorMax = new Vector2(1f, 1f);
            top.pivot = new Vector2(0.5f, 1f);
            top.anchoredPosition = Vector2.zero;
            top.sizeDelta = new Vector2(0f, 88f);
            UiKit.AddHorizontalLayout(top, 22, 16);

            var back = UiKit.CreateButton(top, "Back", "← Назад", () => _onBack(), 18);
            UiKit.SetPreferredHeight(back, 44f, 0f);

            var title = UiKit.CreateText(top, "Title", "Коллекция", 32, Color.white, TextAnchor.MiddleLeft);
            title.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(title, 46f);

            _balances = UiKit.CreateText(
                top, "Balances", string.Empty, 18,
                new Color(0.70f, 0.76f, 0.90f), TextAnchor.MiddleRight);
            UiKit.SetPreferredHeight(_balances, 36f);

            var body = UiKit.CreatePanel(_root, "Body", new Color(0.035f, 0.045f, 0.065f, 0f));
            body.anchorMin = Vector2.zero;
            body.anchorMax = Vector2.one;
            body.offsetMin = new Vector2(40f, 28f);
            body.offsetMax = new Vector2(-40f, -110f);
            UiKit.AddVerticalLayout(body, 8, 10);

            var hint = UiKit.CreateText(
                body,
                "Hint",
                "Разбор даёт пыль: C 5 · R 10 · RR 25 · RRR 100. SP не разбирается.",
                17,
                new Color(0.58f, 0.65f, 0.78f),
                TextAnchor.MiddleLeft);
            UiKit.SetPreferredHeight(hint, 26f);

            var scroll = UiKit.CreateScrollView(body, "CollectionScroll", out _content, 8f);
            var scrollElement = scroll.gameObject.AddComponent<LayoutElement>();
            scrollElement.flexibleHeight = 1f;
            scrollElement.minHeight = 200f;

            _status = UiKit.CreateText(
                body, "Status", string.Empty, 18,
                new Color(0.62f, 0.68f, 0.82f), TextAnchor.MiddleLeft);
            UiKit.SetPreferredHeight(_status, 34f);

            _confirm = BuildConfirm(parent);
            _confirm.gameObject.SetActive(false);

            _root.gameObject.SetActive(false);
            _player.Changed += OnPlayerChanged;
        }

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

        public void Hide()
        {
            UiKit.SetActive(_root, false);
            _confirm.gameObject.SetActive(false);
        }

        public void Dispose()
        {
            if (_disposed)
                return;

            _disposed = true;
            _player.Changed -= OnPlayerChanged;
        }

        private RectTransform BuildConfirm(Transform parent)
        {
            var overlay = UiKit.CreatePanel(parent, "DismantleConfirm", new Color(0f, 0f, 0f, 0.72f));
            var card = UiKit.CreateCenteredCard(
                overlay, "ConfirmCard", new Vector2(620f, 300f),
                new Color(0.08f, 0.10f, 0.14f, 1f));
            UiKit.AddVerticalLayout(card, 30, 12);

            var title = UiKit.CreateText(card, "Title", "Разобрать карту?", 28, Color.white);
            title.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(title, 42f);

            _confirmText = UiKit.CreateText(
                card, "Text", string.Empty, 19,
                new Color(0.72f, 0.78f, 0.92f),
                TextAnchor.MiddleCenter);
            UiKit.SetPreferredHeight(_confirmText, 110f);

            var yes = UiKit.CreateButton(card, "Yes", "Разобрать", OnConfirmDismantle, 20);
            UiKit.SetPreferredHeight(yes, 48f);

            var no = UiKit.CreateButton(card, "No", "Отмена", HideConfirm, 20);
            UiKit.SetPreferredHeight(no, 44f);

            overlay.gameObject.SetActive(false);
            return overlay;
        }

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

            _loading = true;
            SetStatus("Загружаем коллекцию…", new Color(0.62f, 0.68f, 0.82f));

            try
            {
                var collection = await _meta.GetCollectionAsync();
                if (_disposed)
                    return;

                Rebuild(collection.Items ?? new List<CollectionItemDto>());
                SetStatus(
                    collection.Items == null || collection.Items.Count == 0
                        ? "Коллекция пуста. Пройдите онбординг."
                        : "Карт в коллекции: " + collection.Items.Sum(item => item.Count) + ".",
                    new Color(0.62f, 0.68f, 0.82f));
            }
            catch (ApiException exception)
            {
                SetStatus(exception.Message, new Color(1f, 0.55f, 0.45f));
            }
            catch (Exception exception)
            {
                Debug.LogException(exception);
                SetStatus("Не удалось загрузить коллекцию.", new Color(1f, 0.55f, 0.45f));
            }
            finally
            {
                _loading = false;
            }
        }

        private void Rebuild(IReadOnlyList<CollectionItemDto> items)
        {
            for (var i = _content.childCount - 1; i >= 0; i--)
                UnityEngine.Object.Destroy(_content.GetChild(i).gameObject);

            if (items.Count == 0)
                return;

            foreach (var item in items)
                AddRow(item);
        }

        private void AddRow(CollectionItemDto item)
        {
            var row = UiKit.CreatePanel(_content, "Item_" + item.PrintingId, new Color(0.07f, 0.085f, 0.115f, 1f));
            var rowElement = row.gameObject.AddComponent<LayoutElement>();
            rowElement.preferredHeight = 64f;
            UiKit.AddHorizontalLayout(row, 10, 10);

            var name = UiKit.CreateText(
                row, "Name", item.NameEn, 19, Color.white, TextAnchor.MiddleLeft);
            var nameElement = name.gameObject.AddComponent<LayoutElement>();
            nameElement.flexibleWidth = 1f;
            nameElement.preferredHeight = 40f;

            var printing = UiKit.CreateText(
                row, "Printing", item.PrintingId, 16,
                new Color(0.58f, 0.65f, 0.78f), TextAnchor.MiddleLeft);
            var printingElement = printing.gameObject.AddComponent<LayoutElement>();
            printingElement.preferredWidth = 190f;
            printingElement.preferredHeight = 40f;

            var rarity = UiKit.CreateText(
                row, "Rarity", item.Rarity, 17,
                new Color(0.78f, 0.82f, 0.95f));
            var rarityElement = rarity.gameObject.AddComponent<LayoutElement>();
            rarityElement.preferredWidth = 64f;
            rarityElement.preferredHeight = 40f;

            var count = UiKit.CreateText(
                row, "Count", "×" + item.Count, 18,
                new Color(0.78f, 0.82f, 0.95f));
            var countElement = count.gameObject.AddComponent<LayoutElement>();
            countElement.preferredWidth = 54f;
            countElement.preferredHeight = 40f;

            var canDismantle = item.Rarity != "SP" && item.Count > 0;
            var dismantle = UiKit.CreateButton(
                row,
                "Dismantle",
                canDismantle ? "Разобрать 1" : "SP",
                () => ShowConfirm(item),
                16);
            dismantle.interactable = canDismantle;
            var dismantleElement = dismantle.gameObject.AddComponent<LayoutElement>();
            dismantleElement.preferredWidth = 150f;
            dismantleElement.preferredHeight = 44f;
            dismantleElement.flexibleWidth = 0f;
        }

        private void ShowConfirm(CollectionItemDto item)
        {
            _pending = item;
            _confirmText.text = "«" + item.NameEn + "» (" + item.PrintingId + ")\n"
                + "Вы получите " + DustFor(item.Rarity) + " пыли. Осталось: " + item.Count + ".";
            _confirm.SetAsLastSibling();
            _confirm.gameObject.SetActive(true);
        }

        private void HideConfirm()
        {
            _pending = null;
            _confirm.gameObject.SetActive(false);
        }

        private async void OnConfirmDismantle()
        {
            if (_pending == null)
                return;

            var item = _pending;
            _confirm.gameObject.SetActive(false);
            SetStatus("Разбираем " + item.PrintingId + "…", new Color(0.62f, 0.68f, 0.82f));

            try
            {
                await _meta.DismantleAsync(item.PrintingId, 1);
                SetStatus("Разобрано: " + item.PrintingId + ".", new Color(0.45f, 0.85f, 0.55f));
                await LoadAsync();
            }
            catch (ApiException exception)
            {
                SetStatus(exception.Message, new Color(1f, 0.55f, 0.45f));
            }
            catch (Exception exception)
            {
                Debug.LogException(exception);
                SetStatus("Не удалось разобрать карту.", new Color(1f, 0.55f, 0.45f));
            }
            finally
            {
                _pending = null;
            }
        }

        private static int DustFor(string rarity)
        {
            switch (rarity)
            {
                case "C": return 5;
                case "R": return 10;
                case "RR": return 25;
                case "RRR": return 100;
                default: return 0;
            }
        }

        private void OnPlayerChanged()
        {
            if (_disposed || _balances == null)
                return;

            _balances.text = "Gold " + _player.Gold + "   ·   Пыль " + _player.Dust
                + "   ·   Токены " + _player.Tokens;
        }

        private void SetStatus(string text, Color color)
        {
            if (_disposed || _status == null)
                return;

            _status.text = text ?? string.Empty;
            _status.color = color;
        }
    }
}