using System.Collections.Generic;
using ProjectM.Simulation;
using Unity.Entities;
using Unity.Mathematics;
using Unity.NetCode;
using Unity.Transforms;
using UnityEngine;
using static ProjectM.Client.FeedbackFx;

namespace ProjectM.Client
{
    /// <summary>
    /// MC-3/MC-4/A7 — client-only enemy attack TELEGRAPHS. Observe-only presentation <see cref="SystemBase"/> in
    /// <see cref="PresentationSystemGroup"/> that reads replicated state and never mutates the sim. While an enemy's
    /// <see cref="AttackWindup"/> counts down (or a Charger is mid-lunge) it paints a red ground danger shape in the
    /// enemy's facing — a melee cone, a Spitter aim LANE, or the boss's radial SLAM ring / lunge wedge — brightening +
    /// scaling as the strike nears so the player reads WHERE and WHEN to dodge. Also plays a near-impact "dodge NOW"
    /// strike beep once per windup for enemies near the local player. SELF-DETECTS the windup-onset edge via its own
    /// <c>_prevWindup</c> map (a 0 -&gt; nonzero <c>WindUpUntilTick</c> transition arms the anticipation scale-pulse —
    /// this was formerly written by CombatFeedbackSystem's health-scan loop). One pooled mesh per winding-up enemy,
    /// pruned each frame; the tracking maps are pruned against a full enemy-seen set. Extracted from CombatFeedbackSystem;
    /// owns its own FX-root + danger material + beep clip.
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation)]
    [UpdateInGroup(typeof(PresentationSystemGroup))]
    public partial class EnemyDangerTelegraphSystem : SystemBase
    {
        Transform _fxRoot;
        Material _dangerMat;
        readonly Dictionary<Entity, GameObject> _dangerZones = new();
        readonly HashSet<Entity> _dangerSeen = new();          // telegraph-ACTIVE enemies (zone lifecycle: a zone vanishes when its enemy stops winding up)
        readonly List<Entity> _dangerStale = new();            // scratch list reused by every prune
        readonly Dictionary<Entity, float> _pulseStart = new();  // per-enemy windup-onset time (anticipation scale-pulse)
        readonly Dictionary<Entity, uint> _strikeBeeped = new(); // entity -> the WindUpUntilTick it last beeped for (once/windup)
        readonly Dictionary<Entity, uint> _prevWindup = new();   // self-detect the windup-onset edge (was the core _cache.Windup)
        readonly HashSet<Entity> _enemySeen = new();           // ALL enemies this frame (prunes _pulseStart/_strikeBeeped/_prevWindup)
        AudioClip _strikeBeepClip;                             // near-impact "dodge NOW" beep
        AudioClip[] _kindGrowls;                               // per-kind windup voice (attack distinctness)
        Material[] _kindMats;                                  // per-kind telegraph colours (attack distinctness)
        Entity _localPlayer = Entity.Null;

        protected override void OnCreate()
        {
            _strikeBeepClip = MakeClip("strike", 1150f, 1500f, 0.05f, 0.30f, noise: false); // near-impact beep
            // Attack-distinctness: per-kind windup VOICES so kinds read by EAR at onset (0 grunt thud,
            // 1 charger rising roar, 2 spitter wet hiss, 3 swarmer chitter).
            _kindGrowls = new AudioClip[]
            {
                MakeClip("growl_grunt", 180f, 110f, 0.14f, 0.30f, noise: false),
                MakeClip("growl_charger", 90f, 420f, 0.32f, 0.34f, noise: false),
                MakeClip("growl_spitter", 1900f, 500f, 0.18f, 0.26f, noise: true),
                MakeClip("growl_swarmer", 1500f, 2100f, 0.07f, 0.22f, noise: false),
            };
        }

        protected override void OnStartRunning()
        {
            if (_fxRoot != null) return;
            _fxRoot = new GameObject("~EnemyDangerFX").transform;
            _dangerMat = MakeParticleMaterial();
            _dangerMat.name = "EnemyDanger";
            _dangerMat.color = new Color(3.2f, 0.28f, 0.18f, 1f); // HDR red fallback (per-zone intensity in vertex alpha)
            // Attack-distinctness: per-kind telegraph COLORS (0 grunt orange, 1 charger crimson,
            // 2 spitter toxic green, 3 swarmer yellow; the boss shares the charger crimson — shapes differ).
            _kindMats = new Material[4];
            var kindColors = new Color[]
            {
                new Color(3.2f, 0.85f, 0.15f, 1f),
                new Color(3.2f, 0.18f, 0.12f, 1f),
                new Color(0.55f, 2.9f, 0.35f, 1f),
                new Color(2.9f, 2.3f, 0.22f, 1f),
            };
            for (int i = 0; i < 4; i++)
            {
                _kindMats[i] = MakeParticleMaterial();
                _kindMats[i].name = "EnemyDanger_K" + i;
                _kindMats[i].color = kindColors[i];
            }
        }

        protected override void OnDestroy()
        {
            if (_fxRoot != null) Object.Destroy(_fxRoot.gameObject);
            if (_dangerMat != null) Object.Destroy(_dangerMat);
            if (_kindMats != null)
                for (int i = 0; i < _kindMats.Length; i++)
                    if (_kindMats[i] != null) Object.Destroy(_kindMats[i]);
            foreach (var kv in _dangerZones)
                if (kv.Value != null) { var mf = kv.Value.GetComponent<MeshFilter>(); if (mf != null && mf.sharedMesh != null) Object.Destroy(mf.sharedMesh); }
        }

        protected override void OnUpdate()
        {
            if (_fxRoot == null || _dangerMat == null) return;

            // Predicted/physics jobs writing these must finish before this main-thread read.
            EntityManager.CompleteDependencyBeforeRO<LocalTransform>();
            EntityManager.CompleteDependencyBeforeRO<AttackWindup>();
            EntityManager.CompleteDependencyBeforeRO<EnemyStats>();
            EntityManager.CompleteDependencyBeforeRO<EnemyTelegraph>();

            // Local player (strike-beep proximity gate).
            _localPlayer = Entity.Null;
            float3 localPos = default;
            foreach (var (xf, entity) in SystemAPI.Query<RefRO<LocalTransform>>()
                         .WithAll<GhostOwnerIsLocal, PlayerTag>().WithEntityAccess())
            {
                _localPlayer = entity;
                localPos = xf.ValueRO.Position;
            }

            UpdateEnemyDanger(localPos);
        }

        // Enemy attack TELEGRAPH (MC-4 clarity): while an enemy's AttackWindup counts down, paint a red ground danger
        // cone in its facing out to its reach, brightening + scaling as the strike nears -> the player reads WHERE +
        // WHEN to dodge. Client-only, observe-only; one pooled mesh per winding-up enemy, pruned each frame.
        void UpdateEnemyDanger(float3 localPos)
        {
            if (_fxRoot == null || _dangerMat == null) return;
            // Enemies are ownerless INTERPOLATED ghosts, so their replicated AttackWindup arrives on the
            // INTERPOLATION timeline. Timing the danger cone against the PREDICTED ServerTick makes the cue
            // finish ~RTT/2 + interp-buffer ticks EARLY over a real connection — the dodge tell lies. Invisible on
            // loopback, which is exactly why it survived (audit finding M1). Same idiom as ZoneTelegraphSystem.
            Unity.NetCode.NetworkTick serverTick = default;
            if (SystemAPI.TryGetSingleton<NetworkTime>(out var nt))
                serverTick = nt.InterpolationTick.IsValid ? nt.InterpolationTick : nt.ServerTick;
            _dangerSeen.Clear();
            _enemySeen.Clear();

            if (serverTick.IsValid)
            {
                foreach (var (xf, stats, windup, tele, entity) in
                         SystemAPI.Query<RefRO<LocalTransform>, RefRO<EnemyStats>, RefRO<AttackWindup>, RefRO<EnemyTelegraph>>()
                             .WithAll<EnemyTag>().WithEntityAccess())
                {
                    _enemySeen.Add(entity);
                    uint until = windup.ValueRO.WindUpUntilTick;

                    // Self-detect the windup-onset edge (formerly written by the core's health-scan loop): a 0 -> nonzero
                    // transition of WindUpUntilTick arms the anticipation scale-pulse (Feature C). Requires a prior 0
                    // record so a mid-windup relevancy re-entry doesn't spuriously pulse (matches the old prev.Windup==0).
                    bool hadPrev = _prevWindup.TryGetValue(entity, out var pw);
                    if (until != 0u && hadPrev && pw == 0u)
                    {
                        _pulseStart[entity] = (float)SystemAPI.Time.ElapsedTime;
                        // Attack-distinctness: the per-kind windup VOICE at onset (same gate family as the strike beep).
                        if (FeelConfig.StrikeBeepEnabled && _localPlayer != Entity.Null && _kindGrowls != null
                            && math.distancesq(xf.ValueRO.Position, localPos) <= FeelConfig.StrikeBeepMaxDistSq)
                        {
                            byte gk = tele.ValueRO.Kind;
                            if (gk < _kindGrowls.Length && _kindGrowls[gk] != null)
                                PlayClip(_kindGrowls[gk], (Vector3)xf.ValueRO.Position, 0.22f);
                        }
                    }
                    _prevWindup[entity] = until;

                    if (until == 0u) continue;

                    var untilTick = new Unity.NetCode.NetworkTick(until);
                    if (!untilTick.IsValid || !untilTick.IsNewerThan(serverTick)) continue; // windup already elapsed
                    int remaining = untilTick.TicksSince(serverTick);
                    // Feature C: per-enemy windup duration (baked, client-safe) -> ramps 0->1 ending AT impact for
                    // any windup length.
                    float windupDur = math.max(1f, tele.ValueRO.WindupTicks);
                    float intensity = math.saturate(1f - remaining / windupDur);
                    {;

                        // Near-impact strike beep (deferred-items pass): a "dodge NOW" cue once per windup, gated to
                        // enemies near the local player (the danger cone already proves it's winding up to strike).
                        if (FeelConfig.StrikeBeepEnabled && _localPlayer != Entity.Null && remaining <= FeelConfig.StrikeBeepLeadTicks
                            && (!_strikeBeeped.TryGetValue(entity, out var beepedUntil) || beepedUntil != until))
                        {
                            float3 ep = xf.ValueRO.Position;
                            if (math.distancesq(ep, localPos) <= FeelConfig.StrikeBeepMaxDistSq)
                            {
                                PlayClip(_strikeBeepClip, (Vector3)ep, FeelConfig.StrikeBeepVolume);
                                _strikeBeeped[entity] = until;
                            }
                        }

                    }

                    // Feature C: a short anticipation scale-pulse folded into the client-owned cone (never the ghost).
                    float pulse = 0f;
                    if (_pulseStart.TryGetValue(entity, out var t0))
                    {
                        float age = (float)SystemAPI.Time.ElapsedTime - t0;
                        const float PulseLife = 0.18f;
                        if (age < PulseLife) pulse = (1f - age / PulseLife) * 0.35f;
                        else _pulseStart.Remove(entity);
                    }

                    _dangerSeen.Add(entity);
                    if (!_dangerZones.TryGetValue(entity, out var go) || go == null)
                    {
                        go = new GameObject("EnemyDanger");
                        go.transform.SetParent(_fxRoot, false);
                        go.AddComponent<MeshFilter>().sharedMesh = new Mesh { name = "EnemyDanger" };
                        var mr = go.AddComponent<MeshRenderer>();
                        mr.sharedMaterial = _kindMats != null && tele.ValueRO.Kind < _kindMats.Length && _kindMats[tele.ValueRO.Kind] != null
                            ? _kindMats[tele.ValueRO.Kind] : _dangerMat; // per-kind telegraph colour (kind is fixed per entity)
                        mr.shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.Off;
                        mr.receiveShadows = false;
                        _dangerZones[entity] = go;
                    }
                    float coneRange = math.max(1f, stats.ValueRO.AttackRange + 0.6f);
                    // 2026-08-07 audit purge: the boss radial-slam ring, the boss lunge wedge and the Spitter aim
                    // lane are gone with BossState / IsLunging / SpitterState. One enemy kind, one melee wedge.
                    BuildDangerMesh(go.GetComponent<MeshFilter>().sharedMesh, coneRange, 0.7f, intensity);
                    float2 fwd = AnimParamMath.PlanarForward(xf.ValueRO.Rotation);
                    var tr = go.transform;
                    tr.position = (Vector3)xf.ValueRO.Position + Vector3.up * 0.06f;
                    tr.rotation = Quaternion.LookRotation(new Vector3(fwd.x, 0f, fwd.y), Vector3.up);
                    tr.localScale = Vector3.one * (0.92f + 0.12f * intensity + pulse);
                }
            }

            // Zone lifecycle: a zone vanishes the moment its enemy stops winding up (not in _dangerSeen) or despawns.
            if (_dangerZones.Count != _dangerSeen.Count)
            {
                _dangerStale.Clear();
                foreach (var kv in _dangerZones) if (!_dangerSeen.Contains(kv.Key)) _dangerStale.Add(kv.Key);
                for (int i = 0; i < _dangerStale.Count; i++)
                {
                    var g = _dangerZones[_dangerStale[i]];
                    if (g != null) { var mf = g.GetComponent<MeshFilter>(); if (mf != null && mf.sharedMesh != null) Object.Destroy(mf.sharedMesh); Object.Destroy(g); }
                    _dangerZones.Remove(_dangerStale[i]);
                }
            }

            // Prune the tracking maps against the FULL enemy-seen set (a despawned enemy drops its pulse/beep/windup state).
            PruneTracking(_pulseStart);
            PruneTracking(_strikeBeeped);
            PruneTracking(_prevWindup);
        }

        // Remove entries whose enemy wasn't seen this frame (keyed on the full enemy-seen set); reuses _dangerStale.
        void PruneTracking<T>(Dictionary<Entity, T> dict)
        {
            if (dict.Count == 0) return;
            _dangerStale.Clear();
            foreach (var kv in dict) if (!_enemySeen.Contains(kv.Key)) _dangerStale.Add(kv.Key);
            for (int i = 0; i < _dangerStale.Count; i++) dict.Remove(_dangerStale[i]);
        }

        // Filled forward wedge (pizza-slice) from the enemy out to `range`, vertex-alpha ramped by `intensity`.
        static void BuildDangerMesh(Mesh mesh, float range, float halfAngle, float intensity)
        {
            const int seg = 14;
            var verts = new Vector3[seg + 2];
            var cols = new Color[seg + 2];
            var uvs = new Vector2[seg + 2];
            var tris = new int[seg * 3];
            float aCenter = 0.18f + 0.62f * intensity;
            verts[0] = Vector3.zero; cols[0] = new Color(1f, 1f, 1f, aCenter); uvs[0] = new Vector2(0.5f, 0.5f);
            for (int i = 0; i <= seg; i++)
            {
                float a = Mathf.Lerp(-halfAngle, halfAngle, i / (float)seg);
                verts[i + 1] = new Vector3(Mathf.Sin(a) * range, 0f, Mathf.Cos(a) * range);
                cols[i + 1] = new Color(1f, 1f, 1f, aCenter * 0.22f);
                uvs[i + 1] = new Vector2(0.5f, 0.5f);
            }
            for (int i = 0; i < seg; i++) { tris[i * 3] = 0; tris[i * 3 + 1] = i + 1; tris[i * 3 + 2] = i + 2; }
            mesh.Clear();
            mesh.vertices = verts; mesh.colors = cols; mesh.uv = uvs; mesh.triangles = tris;
            mesh.RecalculateBounds();
        }

        // MC-3: a thin forward LANE (filled quad in local +Z) for a Spitter's ranged aim telegraph, vertex-alpha
        // ramped by `intensity` (brightening toward the shot). Built into the same pooled danger mesh; the GO is
        // already rotated to the enemy facing, so +Z is "toward the locked target".
        static void BuildLaneMesh(Mesh mesh, float length, float halfWidth, float intensity)
        {
            float a = 0.18f + 0.62f * intensity;
            var verts = new Vector3[4]
            {
                new Vector3(-halfWidth, 0f, 0.2f),
                new Vector3( halfWidth, 0f, 0.2f),
                new Vector3(-halfWidth, 0f, length),
                new Vector3( halfWidth, 0f, length),
            };
            var cols = new Color[4]
            {
                new Color(1f, 1f, 1f, a),
                new Color(1f, 1f, 1f, a),
                new Color(1f, 1f, 1f, a * 0.12f),
                new Color(1f, 1f, 1f, a * 0.12f),
            };
            var uvs = new Vector2[4] { new Vector2(0.5f, 0.5f), new Vector2(0.5f, 0.5f), new Vector2(0.5f, 0.5f), new Vector2(0.5f, 0.5f) };
            var tris = new int[6] { 0, 2, 1, 1, 2, 3 };
            mesh.Clear();
            mesh.vertices = verts; mesh.colors = cols; mesh.uv = uvs; mesh.triangles = tris;
            mesh.RecalculateBounds();
        }
    }
}