using System.Collections.Generic;
using ProjectM.Simulation;
using Unity.Entities;
using Unity.NetCode;
using Unity.Transforms;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.UIElements;

namespace ProjectM.Client
{
    /// <summary>
    /// The choice-of-3 boon modal (RoomReward) — extracted from <see cref="HudSystem"/> into its own client-only,
    /// observe-only presentation <see cref="SystemBase"/> in <see cref="PresentationSystemGroup"/>. Owns its own
    /// runtime UIDocument sharing <see cref="MenuUi.LoadPanelSettings"/> (sortingOrder 55) so it composes into the
    /// same UITK panel + event dispatcher as the HUD (50) / markers (48) / onboarding (60). Reads the local player's
    /// replicated <see cref="BoonOffer"/> + the <see cref="BoonCatalog"/> blob; card clicks enqueue through
    /// <see cref="BoonSendSystem.PickBoon"/>. Built lazily on first show.
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation)]
    [UpdateInGroup(typeof(PresentationSystemGroup))]
    public partial class BoonModalHudSystem : SystemBase
    {
        GameObject _go;
        UIDocument _doc;
        bool _built;

        VisualElement _boonModal, _boonCardRow;
        int _boonShownFor;    // last exact (Option0|Option1<<8|Option2<<16)+1 signature the modal was built for
        bool _boonModalBuilt;

        protected override void OnStartRunning()
        {
            if (_go != null) return;
            MenuUi.EnsureEventSystem();
            _go = new GameObject("~HUDBoonModal");
            _doc = _go.AddComponent<UIDocument>();
            _doc.panelSettings = MenuUi.LoadPanelSettings();
            _doc.sortingOrder = 55;
        }

        protected override void OnDestroy()
        {
            if (_go != null) Object.Destroy(_go);
        }

        protected override void OnUpdate()
        {
            if (_doc == null) return;
            var root = _doc.rootVisualElement;
            if (root == null) return; // panel not initialised yet (next frame)
            if (!_built)
            {
                root.style.position = Position.Absolute;
                root.style.left = 0; root.style.right = 0; root.style.top = 0; root.style.bottom = 0;
                root.pickingMode = PickingMode.Ignore; // never eat game-world clicks
                _built = true;
            }

            bool haveRun = SystemAPI.TryGetSingleton<RunInfo>(out var runInfo);

            BoonOffer localOffer = default;
            bool hasOffer = false;
            foreach (var off in SystemAPI.Query<RefRO<BoonOffer>>().WithAll<PlayerTag, GhostOwnerIsLocal>())
            {
                localOffer = off.ValueRO;
                hasOffer = true;
                break;
            }
            BlobAssetReference<BoonCatalogBlob> boonPool = default;
            if (SystemAPI.TryGetSingleton<BoonCatalog>(out var bcat))
                boonPool = bcat.Value;
            // Lifecycle gate (post-impl review): even a stale replicated Pending never shows the modal outside
            // the reward window.
            UpdateBoonModal(localOffer, hasOffer && localOffer.Pending == 1
                && haveRun && runInfo.Lifecycle == RunLifecycle.RoomReward, boonPool);
        }

        void UpdateBoonModal(BoonOffer offer, bool show, BlobAssetReference<BoonCatalogBlob> pool)
        {
            if (!show || !pool.IsCreated)
            {
                if (_boonModal != null) _boonModal.style.display = DisplayStyle.None;
                _boonShownFor = 0;
                return;
            }
            var root = _doc != null ? _doc.rootVisualElement : null;
            if (root == null) return;
            if (!_boonModalBuilt)
            {
                BuildBoonModal(root);
                _boonModalBuilt = true;
            }

            // Rebuild the three cards only when the offer actually changes (a new room's deal).
            // Exact signature (post-impl review): the old lossy byte XOR could collide across consecutive
            // rooms and leave stale card labels. +1 keeps 0 as the hidden/reset sentinel.
            int sig = 1 + (offer.Option0 | (offer.Option1 << 8) | (offer.Option2 << 16));
            if (_boonShownFor != sig)
            {
                _boonCardRow.Clear();
                ref var defs = ref pool.Value;
                for (byte k = 0; k < 3; k++)
                {
                    byte id = k == 2 ? offer.Option2 : k == 1 ? offer.Option1 : offer.Option0;
                    int idx = BoonMath.FindDef(ref defs, id);
                    string title = idx >= 0 ? defs.Defs[idx].Name.ToString() : ("BOON " + id);
                    string desc = idx >= 0 ? defs.Defs[idx].Desc.ToString() : "";
                    byte weight = idx >= 0 ? defs.Defs[idx].Weight : (byte)100;
                    byte pick = k; // capture a COPY into the closure, never the loop variable
                    var card = MenuUi.Button(title + "\n" + desc, () => BoonSendSystem.PickBoon(pick));
                    card.style.width = 200;
                    card.style.height = StyleKeyword.Auto; // long descs grow the card
                    card.style.minHeight = 96;
                    // Rarity from the draw weight (100 common / 60 uncommon / 30 rare / 10 epic).
                    var rare = weight <= 10 ? new Color(1f, 0.82f, 0.30f)
                        : weight <= 30 ? new Color(0.65f, 0.50f, 1f)
                        : weight <= 60 ? new Color(0.45f, 0.95f, 0.55f)
                        : new Color(1f, 1f, 1f, 0.30f);
                    MenuUi.Border(card, rare, weight <= 30 ? 2.5f : 1.5f);
                    card.style.marginLeft = 8;
                    card.style.marginRight = 8;
                    card.style.whiteSpace = WhiteSpace.Normal;
                    _boonCardRow.Add(card);
                }
                _boonShownFor = sig;
            }
            _boonModal.style.display = DisplayStyle.Flex;
        }

        void BuildBoonModal(VisualElement root)
        {
            _boonModal = new VisualElement { pickingMode = PickingMode.Ignore };
            _boonModal.style.position = Position.Absolute;
            _boonModal.style.left = 0; _boonModal.style.right = 0;
            _boonModal.style.top = 0; _boonModal.style.bottom = 0;
            _boonModal.style.alignItems = Align.Center;
            _boonModal.style.justifyContent = Justify.Center;
            _boonModal.style.display = DisplayStyle.None;

            var box = new VisualElement();
            box.style.backgroundColor = new Color(0.07f, 0.09f, 0.12f, 0.96f);
            box.style.borderTopLeftRadius = 10; box.style.borderTopRightRadius = 10;
            box.style.borderBottomLeftRadius = 10; box.style.borderBottomRightRadius = 10;
            box.style.paddingLeft = 18; box.style.paddingRight = 18;
            box.style.paddingTop = 14; box.style.paddingBottom = 16;
            box.style.alignItems = Align.Center;

            var title = new Label("ROOM CLEARED  —  CHOOSE A BOON");
            title.style.color = new Color(0.6f, 1f, 0.7f);
            title.style.fontSize = 18;
            title.style.unityFontStyleAndWeight = FontStyle.Bold;
            title.style.marginBottom = 12;
            box.Add(title);

            _boonCardRow = new VisualElement();
            _boonCardRow.style.flexDirection = FlexDirection.Row;
            box.Add(_boonCardRow);

            _boonModal.Add(box);
            root.Add(_boonModal);
        }
    }
}