using System;
using Luneraria.Core;
using UnityEngine;

namespace Luneraria.View
{
    /// <summary>
    /// Visual twin of one LuneUnit (port of scripts/luneraria/view/lune_unit_view.gd). Reads the
    /// authoritative state and never writes back: position between the last two fixed steps,
    /// facing, clips from real combat events (attack and ability serials), team ring, health bar,
    /// and for a deployed boss the wide owner ring of its team (G3: round for Blau, diamond for Rot).
    /// </summary>
    public sealed class LuneUnitView : MonoBehaviour
    {
        public LuneUnit Unit { get; private set; }

        LuneGround _ground;
        Transform _model;
        Animator _animator;
        bool _skeletal;
        float _height = 1.6f;
        Transform _ring;
        Transform _ownerRing;
        Transform _bars;
        Transform _fill;
        int _lastAttack;
        int _lastAbility;
        float _attackFlash;
        float _time;
        Vector3 _lastVisual;
        string _clip = "";
        bool _attackB;
        bool _deathShown;
        Renderer[] _renderers;
        /// <summary>Base colour and emission of every material slot per renderer: a flash tints them instead of replacing them.</summary>
        Color[][] _baseColors;
        Color[][] _emissions;
        bool _flashing;
        /// <summary>Last applied flash state (strength and warmth in 16 steps each); unchanged steps skip the blocks.</summary>
        int _flashKey = -1;
        MaterialPropertyBlock _flashBlock;

        public void Bind(LuneUnit unit, LuneUnitLibrary library)
        {
            Unit = unit;
            _ground = library.Ground;
            name = "Unit_" + unit.Id + "_" + unit.Kind;
            GameObject prefab = library.PrefabFor(unit, out RuntimeAnimatorController controller);
            _model = Instantiate(prefab, transform, false).transform;
            _model.name = "Model";
            _model.gameObject.SetActive(true);
            float scale = (float)Math.Max(.1, unit.Def.ViewScale);
            _model.localScale = Vector3.one * scale;
            library.Materials.Dress(_model.gameObject, unit.Team);
            _renderers = _model.GetComponentsInChildren<Renderer>();
            _baseColors = new Color[_renderers.Length][];
            _emissions = new Color[_renderers.Length][];
            for (int r = 0; r < _renderers.Length; r++)
            {
                Material[] slots = _renderers[r].sharedMaterials;
                _baseColors[r] = new Color[slots.Length];
                _emissions[r] = new Color[slots.Length];
                for (int i = 0; i < slots.Length; i++)
                {
                    _baseColors[r][i] = slots[i] != null && slots[i].HasProperty("_BaseColor") ? slots[i].GetColor("_BaseColor") : Color.white;
                    _emissions[r][i] = slots[i] != null && slots[i].HasProperty("_EmissionColor") ? slots[i].GetColor("_EmissionColor") : Color.black;
                }
            }
            _flashBlock = new MaterialPropertyBlock();
            _animator = _model.GetComponentInChildren<Animator>();
            _skeletal = controller != null && _animator != null;
            if (_skeletal)
            {
                _animator.runtimeAnimatorController = controller;
                _animator.applyRootMotion = false;
                _animator.gameObject.AddComponent<LuneContactReceiver>();
            }
            var bounds = new Bounds(transform.position, Vector3.zero);
            foreach (Renderer renderer in _model.GetComponentsInChildren<Renderer>())
                bounds.Encapsulate(renderer.bounds);
            _height = Mathf.Max(1f, bounds.max.y - transform.position.y);

            int team = Mathf.Clamp(unit.Team, 0, 2);
            _ring = Marker("Ring", team == 0 ? library.RingRound : team == 1 ? library.RingDiamond : library.RingHexagon,
                unit.Kind == "hero" ? library.HeroRing : library.TeamRing[team]);
            _ring.localScale = new Vector3(scale, 1f, scale);
            _ring.localPosition = new Vector3(0f, .05f, 0f);
            if (unit.Kind == "boss" && unit.Team <= 1 && library.OwnerRingRound != null)
            {
                _ownerRing = Marker("OwnerRing", unit.Team == 0 ? library.OwnerRingRound : library.OwnerRingDiamond, library.OwnerRing[unit.Team]);
                _ownerRing.localScale = new Vector3(scale, 1f, scale);
                _ownerRing.localPosition = new Vector3(0f, .07f, 0f);
            }
            _bars = new GameObject("Bars").transform;
            _bars.SetParent(transform, false);
            _bars.localPosition = new Vector3(0f, _height + .25f, 0f);
            Transform back = Marker("Back", library.Quad, library.BarBack);
            back.SetParent(_bars, false);
            back.localScale = new Vector3(.9f, .1f, 1f);
            _fill = Marker("Fill", library.Quad, library.BarFill[team]);
            _fill.SetParent(_bars, false);
            _fill.localScale = new Vector3(.86f, .07f, 1f);
            _fill.localPosition = new Vector3(0f, 0f, -.001f);
            _lastAttack = unit.AttackSerial;
            _lastAbility = unit.AbilitySerial;
            transform.position = Ground(unit.Position);
            transform.rotation = LuneSpace.Facing(unit.Facing);
            _lastVisual = transform.position;
            Play("idle");
        }

        Transform Marker(string label, Mesh mesh, Material material)
        {
            var go = new GameObject(label);
            go.transform.SetParent(transform, false);
            go.AddComponent<MeshFilter>().sharedMesh = mesh;
            var renderer = go.AddComponent<MeshRenderer>();
            renderer.sharedMaterial = material;
            renderer.shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.Off;
            renderer.receiveShadows = false;
            return go.transform;
        }

        Vector3 Ground(Vec2 at)
        {
            return LuneSpace.World(at, (_ground != null ? _ground.StandHeight(at) : 0f) + .03f);
        }

        /// <summary>Where tower bolts hit this figure (upper body).</summary>
        public Vector3 AimPoint { get { return transform.position + Vector3.up * _height * .55f; } }

        /// <summary>Anchor of the name tag above the head (Godot tag.position.y = height + .55).</summary>
        public Vector3 TagPoint { get { return transform.position + Vector3.up * (_height + .55f); } }

        public void Sync(float alpha, float dt, Transform camera)
        {
            _time += dt;
            Vec2 at = Unit.PreviousPosition.Lerp(Unit.Position, Mathf.Clamp01(alpha));
            transform.position = Ground(at);
            transform.rotation = Quaternion.Slerp(transform.rotation, LuneSpace.Facing(Unit.Facing), Mathf.Min(1f, dt * 12f));
            float moved = Vector2.Distance(new Vector2(transform.position.x, transform.position.z), new Vector2(_lastVisual.x, _lastVisual.z));
            _lastVisual = transform.position;
            bool attacked = Unit.AttackSerial != _lastAttack;
            bool ability = Unit.AbilitySerial != _lastAbility;
            _lastAttack = Unit.AttackSerial;
            _lastAbility = Unit.AbilitySerial;
            if (attacked || ability)
                _attackFlash = .28f;
            _attackFlash = Mathf.Max(0f, _attackFlash - dt);
            HitFlashGlow();
            if (_skeletal)
                AnimateSkeletal(moved, attacked, ability);
            else
                AnimateRigid(moved);
            float fraction = Mathf.Clamp01((float)(Unit.Hp / Math.Max(1.0, Unit.MaxHp)));
            _fill.localScale = new Vector3(.86f * Mathf.Max(.001f, fraction), .07f, 1f);
            _fill.localPosition = new Vector3(-.43f * (1f - fraction), 0f, -.001f);
            _bars.gameObject.SetActive(Unit.Alive && fraction < .999f);
            if (camera != null)
                _bars.rotation = camera.rotation;
            _ring.gameObject.SetActive(Unit.Alive);
            if (_ownerRing != null)
                _ownerRing.gameObject.SetActive(Unit.Alive);
            // Rigid figures have no death clip; skeletal ones stay down in their death pose.
            if (!_skeletal)
                _model.gameObject.SetActive(Unit.Alive);
        }

        /// <summary>Share of the flash colour in a slot's base colour at full flash.</summary>
        public const float FlashTint = .3f;
        /// <summary>Emission the flash adds at full strength (on materials that emit).</summary>
        public const float FlashEmission = .15f;

        /// <summary>
        /// U5: white hit flash of the core's HitFlash (0.18 s on Take) plus a short warm attack
        /// glow. A MaterialPropertyBlock per material slot keeps the shared team materials
        /// untouched. U5.3: the flash tints each slot's own base colour and adds a little to its
        /// own emission. U5 set one near-white base colour and a strong emission for all slots,
        /// so in a melee, where nearly every figure attacks or is hit, the armies turned white,
        /// the boss glowed yellow and its crystals lost their team colour.
        /// </summary>
        void HitFlashGlow()
        {
            if (_renderers == null || _renderers.Length == 0)
                return;
            float hit = (float)Unit.HitFlash;
            float glow = Mathf.Clamp01(Mathf.Max(hit / .18f, _attackFlash / .28f));
            if (glow <= .001f)
            {
                if (!_flashing)
                    return;
                _flashing = false;
                _flashKey = -1;
                for (int r = 0; r < _renderers.Length; r++)
                {
                    if (_renderers[r] == null)
                        continue;
                    for (int i = 0; i < _baseColors[r].Length; i++)
                        _renderers[r].SetPropertyBlock(null, i);
                }
                return;
            }
            // Attack flash is warm (the figure lunges); a taken hit is white-hot. The flash
            // fades over 0.18–0.28 s; 16 steps of strength and warmth are enough for the eye and
            // save most per-slot block updates of a melee.
            int level = Mathf.CeilToInt(glow * 16f);
            int warmth = Mathf.RoundToInt(Mathf.Clamp01(hit / .18f) * 16f);
            int key = level * 17 + warmth;
            if (key == _flashKey)
                return;
            _flashKey = key;
            glow = level / 16f;
            float white = warmth / 16f;
            Color color = Color.Lerp(new Color(1f, .72f, .35f), Color.white, white);
            _flashing = true;
            for (int r = 0; r < _renderers.Length; r++)
            {
                if (_renderers[r] == null)
                    continue;
                for (int i = 0; i < _baseColors[r].Length; i++)
                {
                    _flashBlock.Clear();
                    _flashBlock.SetColor("_BaseColor", Color.Lerp(_baseColors[r][i], color, glow * FlashTint));
                    _flashBlock.SetColor("_EmissionColor", _emissions[r][i] + color * (glow * FlashEmission));
                    _renderers[r].SetPropertyBlock(_flashBlock, i);
                }
            }
        }

        void AnimateSkeletal(float moved, bool attacked, bool ability)
        {
            if (!Unit.Alive)
            {
                if (!_deathShown)
                    Play("death");
                _deathShown = true;
                return;
            }
            if (ability)
                Play("ability", true);
            else if (attacked)
            {
                Play(_attackB ? "attack_b" : "attack_a", true);
                _attackB = !_attackB;
            }
            else if (IsPlaying("attack_a") || IsPlaying("attack_b") || IsPlaying("ability"))
                return;
            else
                Play(moved > .002f ? "walk" : "idle");
        }

        bool IsPlaying(string state)
        {
            AnimatorStateInfo info = _animator.GetCurrentAnimatorStateInfo(0);
            return info.IsName(state) && info.normalizedTime < .95f;
        }

        void Play(string state, bool restart = false)
        {
            if (!_skeletal || (_clip == state && !restart))
                return;
            // Figures have the clips they were built with (the worker has no combat clips).
            if (!_animator.HasState(0, Animator.StringToHash(state)))
                return;
            _clip = state;
            _animator.CrossFadeInFixedTime(state, .12f, 0, 0f);
        }

        /// <summary>Rigid figures: a stride bob while walking and a short lunge on attacks.</summary>
        void AnimateRigid(float moved)
        {
            float bob = moved > .002f ? Mathf.Abs(Mathf.Sin((_time + Unit.Id * .23f) * 9f)) * .08f : 0f;
            float lunge = Mathf.Sin(Mathf.Clamp01(_attackFlash / .28f) * Mathf.PI) * .25f;
            _model.localPosition = new Vector3(0f, bob, lunge);
        }
    }
}