using System;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.UI;
using Vanguard.Api;
using Vanguard.Api.Contracts;
using Vanguard.Meta;
using Vanguard.Shared.Protocol;

namespace Vanguard.UI
{
    /// <summary>Просмотр реплея: события и кадры состояния, собранные сервером.</summary>
    public sealed class ReplayView
    {
        private readonly MetaService _meta;
        private readonly Action _onClose;

        private readonly RectTransform _root;
        private readonly Text _title;
        private readonly Text _result;
        private readonly Text _frameLabel;
        private readonly Text _summary;
        private readonly Text _status;
        private readonly RectTransform _events;
        private ReplayResponseDto _replay;
        private int _frameIndex;
        private bool _loading;

        public ReplayView(Transform parent, MetaService meta, Action onClose)
        {
            _meta = meta;
            _onClose = onClose;

            _root = UiKit.CreatePanel(parent, "ReplayScreen", new Color(0.015f, 0.025f, 0.05f, 0.97f));

            var top = UiKit.CreatePanel(_root, "TopBar", new Color(0.06f, 0.08f, 0.13f, 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", "← К истории", () => _onClose(), 18);
            UiKit.SetPreferredHeight(back, 44f, 0f);

            _title = UiKit.CreateText(top, "Title", "Реплей", 30, Color.white, TextAnchor.MiddleLeft);
            _title.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(_title, 46f);

            _result = UiKit.CreateText(top, "Result", string.Empty, 20,
                new Color(0.85f, 0.90f, 1f), TextAnchor.MiddleRight);
            UiKit.SetPreferredHeight(_result, 36f);

            var body = UiKit.CreatePanel(_root, "Body", new Color(0f, 0f, 0f, 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 summaryPanel = UiKit.CreatePanel(body, "SummaryPanel", new Color(0.06f, 0.08f, 0.13f, 1f));
            UiKit.SetPreferredHeight(summaryPanel, 250f);
            UiKit.AddVerticalLayout(summaryPanel, 18, 8);

            _frameLabel = UiKit.CreateText(
                summaryPanel, "Frame", "Кадр", 19, Color.white, TextAnchor.MiddleLeft);
            _frameLabel.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(_frameLabel, 28f);

            _summary = UiKit.CreateText(
                summaryPanel, "Summary", string.Empty, 16,
                new Color(0.72f, 0.78f, 0.92f), TextAnchor.UpperLeft);
            _summary.horizontalOverflow = HorizontalWrapMode.Wrap;
            UiKit.SetPreferredHeight(_summary, 170f);

            var controls = UiKit.CreatePanel(body, "Controls", new Color(0f, 0f, 0f, 0f));
            UiKit.SetPreferredHeight(controls, 52f);
            UiKit.AddHorizontalLayout(controls, 0, 12);

            var prev = UiKit.CreateButton(controls, "Prev", "◀ Кадр", OnPrev, 18);
            UiKit.SetPreferredHeight(prev, 46f);
            var next = UiKit.CreateButton(controls, "Next", "Кадр ▶", OnNext, 18);
            UiKit.SetPreferredHeight(next, 46f);

            var eventsTitle = UiKit.CreateText(
                body, "EventsTitle", "События", 22, Color.white, TextAnchor.MiddleLeft);
            eventsTitle.fontStyle = FontStyle.Bold;
            UiKit.SetPreferredHeight(eventsTitle, 30f);

            var scroll = UiKit.CreateScrollView(body, "EventsScroll", out _events, 4f);
            var scrollElement = scroll.gameObject.AddComponent<LayoutElement>();
            scrollElement.flexibleHeight = 1f;
            scrollElement.minHeight = 160f;

            _status = UiKit.CreateText(
                body, "Status", string.Empty, 17,
                new Color(0.62f, 0.68f, 0.82f), TextAnchor.MiddleLeft);
            UiKit.SetPreferredHeight(_status, 30f);

            _root.gameObject.SetActive(false);
        }

        public void Show(string matchId)
        {
            UiKit.SetActive(_root, true);
            _replay = null;
            _frameIndex = 0;
            SetStatus("Загружаем реплей…", new Color(0.62f, 0.68f, 0.82f));
            _ = LoadAsync(matchId);
        }

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

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

            _loading = true;
            try
            {
                _replay = await _meta.GetReplayAsync(matchId);
                if (_root == null || !_root.gameObject.activeSelf)
                    return;

                _title.text = "Реплей · " + _replay.MatchId;
                _result.text = _replay.Winner == _replay.ViewerSeat
                    ? "Победа"
                    : _replay.Winner < 0 ? "Ничья" : "Поражение";
                _result.color = _replay.Winner == _replay.ViewerSeat
                    ? new Color(0.45f, 0.85f, 0.55f)
                    : new Color(1f, 0.58f, 0.45f);

                _frameIndex = Math.Max(0, (_replay.Frames?.Count ?? 0) - 1);
                RebuildEvents();
                UpdateFrame();
                SetStatus(
                    "Кадров: " + (_replay.Frames?.Count ?? 0) + " · событий: "
                    + (_replay.Events?.Count ?? 0),
                    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 реплей.", new Color(1f, 0.55f, 0.45f));
            }
            finally
            {
                _loading = false;
            }
        }

        private void RebuildEvents()
        {
            ClearChildren(_events);
            if (_replay?.Events == null || _replay.Events.Count == 0)
            {
                var empty = UiKit.CreateText(
                    _events, "Empty", "Событий нет.", 16,
                    new Color(0.62f, 0.68f, 0.82f));
                UiKit.SetPreferredHeight(empty, 60f);
                return;
            }

            foreach (var item in _replay.Events)
            {
                var line = UiKit.CreateText(
                    _events,
                    "Event",
                    "#" + item.Seq + "  " + item.Kind,
                    15,
                    new Color(0.72f, 0.78f, 0.92f),
                    TextAnchor.MiddleLeft);
                UiKit.SetPreferredHeight(line, 22f);
            }
        }

        private void OnPrev()
        {
            if (_replay?.Frames == null || _replay.Frames.Count == 0)
                return;

            _frameIndex = Math.Max(0, _frameIndex - 1);
            UpdateFrame();
        }

        private void OnNext()
        {
            if (_replay?.Frames == null || _replay.Frames.Count == 0)
                return;

            _frameIndex = Math.Min(_replay.Frames.Count - 1, _frameIndex + 1);
            UpdateFrame();
        }

        private void UpdateFrame()
        {
            if (_replay?.Frames == null || _replay.Frames.Count == 0)
            {
                _frameLabel.text = "Кадров нет";
                _summary.text = string.Empty;
                return;
            }

            var frame = _replay.Frames[Mathf.Clamp(_frameIndex, 0, _replay.Frames.Count - 1)];
            _frameLabel.text = "Кадр " + (_frameIndex + 1) + " / " + _replay.Frames.Count
                + "   ·   eventSeq " + frame.EventSeq;

            var view = frame.View;
            if (view == null)
            {
                _summary.text = "Состояние кадра недоступно.";
                return;
            }

            var text = "Фаза: " + view.Phase + " · шаг: " + view.Step
                + " · ход " + view.TurnNumber
                + " · решает: " + (view.ActivePlayer == view.You ? "вы" : "противник")
                + "\n";

            var opponent = view.You == 0 ? 1 : 0;
            foreach (var index in new[] { view.You, opponent })
            {
                if (view.Players == null || index >= view.Players.Count)
                    continue;

                var player = view.Players[index];
                text += (index == view.You ? "Вы: " : "Противник: ") + player.Name
                    + " · рука " + player.HandCount
                    + " · колода " + player.DeckCount
                    + " · урон " + (player.FaceDownDamage + player.FaceUpDamage.Count)
                    + " · Vanguard " + (player.Vanguard?.PrintingId ?? "—")
                    + "\n   RG: " + RearGuards(player) + "\n";
            }

            _summary.text = text;
        }

        private static string RearGuards(PlayerView player)
        {
            if (player.RearGuards == null)
                return "—";

            var parts = new System.Collections.Generic.List<string>();
            for (var i = 0; i < player.RearGuards.Length; i++)
            {
                var card = player.RearGuards[i];
                parts.Add("R" + (i + 1) + ":" + (card?.PrintingId ?? "—"));
            }

            return string.Join(" · ", parts);
        }

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

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

        private static void ClearChildren(Transform parent)
        {
            for (var i = parent.childCount - 1; i >= 0; i--)
                UnityEngine.Object.Destroy(parent.GetChild(i).gameObject);
        }
    }
}