using System.Collections.Generic;
using UnityEngine;

namespace TKS
{
    /// <summary>
    /// 조준 미리보기(PD #1097 §6 + #1098 §3): 이 슬링샷을 가상 실행(Sim · 연출 없음 · 숨은 함정 모름)해 그 결과를 그린다 —
    /// 행동 유닛 실제 경로(튕김·연쇄·창병 반작용·빙판 미끄러짐 = 점선) · 밀릴 유닛 궤적(상대 = 주황 · 같은 편 = 하늘 점선) ·
    /// 장애물에 닿는 지점 = 붉게 끊김 + 결과 글자(내구 −n · 파괴 · 굴림 · 밀림 · 폭발 · 튕김) · 지나는 지대 = 색 띠(늪 갈색 · 독 보라 · 불 주황 · 빙판 하늘 · 고지 황토 · 안개 흰색).
    /// </summary>
    public class GimmickPreview
    {
        static readonly Color MoverColor = new Color(1f, 0.95f, 0.5f, 0.95f);
        static readonly Color FoeTrackColor = new Color(1f, 0.6f, 0.15f, 0.9f);
        static readonly Color AllyTrackColor = new Color(0.45f, 0.8f, 1f, 0.9f);
        static readonly Color CutColor = new Color(1f, 0.15f, 0.15f, 0.9f);
        static readonly Color IconColor = new Color(1f, 0.85f, 0.35f);

        readonly GimmickLayer layer;
        readonly Transform root;
        readonly List<LineRenderer> dashes = new List<LineRenderer>();
        readonly List<LineRenderer> bands = new List<LineRenderer>();
        readonly List<TextMesh> icons = new List<TextMesh>();
        LineRenderer cut;
        static Material dashMaterial;
        static Material solidMaterial;
        int usedDash, usedBand, usedIcon;

        /// <summary>마지막 미리보기 결과(테스트 확인용).</summary>
        public readonly List<string> LastIcons = new List<string>();
        public readonly List<Color> LastBandColors = new List<Color>();
        public int LastTracks;
        public bool LastCut;
        public Vector2 LastMoverEnd;

        public GimmickPreview(GimmickLayer l)
        {
            layer = l;
            var go = new GameObject("AimPreview");
            go.transform.SetParent(l.transform, false);
            root = go.transform;
        }

        public static Color BandColor(GimmickZone z)
        {
            switch (z)
            {
                case GimmickZone.Slow: return new Color(0.55f, 0.38f, 0.15f, 0.75f);
                case GimmickZone.Poison: return new Color(0.7f, 0.35f, 0.95f, 0.75f);
                case GimmickZone.Burn: return new Color(1f, 0.5f, 0.1f, 0.75f);
                case GimmickZone.Slide: return new Color(0.55f, 0.9f, 1f, 0.75f);
                case GimmickZone.High: return new Color(0.85f, 0.7f, 0.35f, 0.7f);
                case GimmickZone.Fog: return new Color(0.95f, 0.95f, 1f, 0.6f);
                case GimmickZone.River: return new Color(0.25f, 0.5f, 0.95f, 0.75f);
            }
            return new Color(1f, 1f, 1f, 0f);
        }

        public bool Visible
        {
            get { return usedDash + usedBand + usedIcon > 0 || (cut != null && cut.enabled); }
        }

        public void Hide()
        {
            usedDash = usedBand = usedIcon = 0;
            Flush();
            if (cut != null) cut.enabled = false;
        }

        /// <summary>조준 중 1회(드래그 프레임마다). shot = 궁·책 사격 계획(있으면 막힘·폭발 글자).</summary>
        public void Show(Unit u, Vector2 target, bool moveOnly, ActionResolver.ShotPlan shot)
        {
            usedDash = usedBand = usedIcon = 0;
            LastIcons.Clear();
            LastBandColors.Clear();
            LastTracks = 0;
            LastCut = false;
            if (cut != null) cut.enabled = false;
            var bm = layer.Battle;
            if (u == null || bm == null || !u.IsAlive)
            {
                Flush();
                return;
            }

            // 가상 실행(연출 없음 · 숨은 함정 모름 · 상태는 되돌린다)
            var snap = Sim.Take(bm);
            var gBefore = new List<KeyValuePair<GimmickInstance, int>>();
            var gPos = new List<Vector2>();
            foreach (var g in layer.Items)
            {
                gBefore.Add(new KeyValuePair<GimmickInstance, int>(g, g.Hp * 4 + (g.Broken ? 1 : 0) + (g.Removed ? 2 : 0)));
                gPos.Add(g.Shape.Center);
            }
            var o = new ActionOutcome();
            var events = new List<string>();
            var moverPath = new List<Vector2>();
            var tracks = new List<KeyValuePair<Unit, Displacement>>();
            Sim.Active = true;
            GimmickLayer.PreviewMode = true;
            try
            {
                var resolver = new ActionResolver(bm.Config, bm, new System.Random(7));
                Sim.Run(resolver.Resolve(u, target, moveOnly, o));
                moverPath.AddRange(o.Path);
                foreach (var d in o.Displaced) tracks.Add(new KeyValuePair<Unit, Displacement>(d.Unit, d));
                for (int i = 0; i < gBefore.Count && i < layer.Items.Count; i++)
                {
                    var g = gBefore[i].Key;
                    int before = gBefore[i].Value;
                    int beforeHp = before / 4;
                    if (g.Broken && (before & 1) == 0) events.Add(g.Def.projectile == GimmickProjectile.Destroy ? g.Def.nameKo + " 폭발" : g.Def.nameKo + " 파괴");
                    else if (g.Hp < beforeHp) events.Add(g.Def.nameKo + " −" + (beforeHp - g.Hp));
                    if (g.Removed && (before & 2) == 0 && g.Zone != GimmickZone.Trap) events.Add(g.Def.nameKo + " 제거");
                    if ((g.Shape.Center - gPos[i]).sqrMagnitude > 1e-4f) events.Add(g.Def.nameKo + (g.Rolls ? " 굴림" : " 밀림"));
                }
                if (o.Chains > 0) events.Add("연쇄 " + o.Chains);
                foreach (var n in o.Notes)
                {
                    if (n.Contains("미끄러짐")) events.Add("미끄러짐");
                    if (n.Contains("강에 빠짐")) events.Add("강에 빠짐");
                    if (n.Contains("안개 걷힘")) events.Add("안개 걷힘");
                    int k = n.IndexOf("자기 −");
                    if (k >= 0) events.Add(n.Substring(k)); // 튕김 자기 피해(bounce_pct · cav_self_pct)
                }
            }
            finally
            {
                Sim.Active = false;
                GimmickLayer.PreviewMode = false;
                Sim.Restore(bm, snap);
            }

            // 행동 유닛 = 첫 접촉 뒤 궤적(튕김·연쇄·반작용·미끄러짐)만 점선(첫 구간은 조준선) · 첫 구간이 장애물에서 끝났으면 그 뒤(조준점까지)를 붉게 끊는다
            if (moverPath.Count >= 2)
            {
                LastMoverEnd = moverPath[moverPath.Count - 1];
                if (moverPath.Count > 2)
                {
                    Dash(moverPath.GetRange(1, moverPath.Count - 1), MoverColor);
                    LastTracks++;
                }
                Vector2 aimEnd = bm.Resolver.ReachPoint(u, target);
                Vector2 firstEnd = moverPath[1];
                if (!UnitTypeInfo.IsRanged(u.Type) && Vector2.Distance(firstEnd, aimEnd) > 0.15f && BlockNear(firstEnd, u.Radius))
                {
                    Cut(firstEnd, aimEnd);
                    if (o.Path.Count > 2 && !events.Contains("미끄러짐")) events.Add("튕김");
                }
                Bands(moverPath, u.Faction == Faction.Player);
            }
            foreach (var kv in tracks)
            {
                if (kv.Key == null || Vector2.Distance(kv.Value.From, kv.Value.To) < 0.05f) continue;
                Dash(new List<Vector2> { kv.Value.From, kv.Value.To }, kv.Key.Faction == u.Faction ? AllyTrackColor : FoeTrackColor);
                LastTracks++;
            }
            if (shot != null && shot.HitGimmick != null && shot.Hit == null)
            {
                string t = shot.HitGimmick.Def.projectile == GimmickProjectile.Destroy ? shot.HitGimmick.Def.nameKo + " 폭발" : shot.HitGimmick.Def.nameKo + "에 막힘";
                if (!events.Contains(t)) events.Add(t);
            }
            if (events.Count > 0)
            {
                Vector2 at = shot != null && shot.Fires ? shot.To : (moverPath.Count >= 2 ? moverPath[1] : u.Position);
                Icon(at, string.Join(" · ", events.ToArray()));
            }
            Flush();
        }

        /// <summary>그 지점에서 장애물 콜라이더(강 = 다리 구간을 뺀 조각)에 닿아 있는가.</summary>
        static bool BlockNear(Vector2 p, float r)
        {
            Physics2D.SyncTransforms();
            foreach (var c in Physics2D.OverlapCircleAll(p, r * Combat.CastRadiusScale + 0.08f))
            {
                if (GimmickLayer.BlocksMove(c)) return true;
            }
            return false;
        }

        void Bands(List<Vector2> path, bool player)
        {
            foreach (var g in layer.Items)
            {
                if (!g.ZoneActive || g.Zone == GimmickZone.Trap || g.Zone == GimmickZone.Capture || g.Zone == GimmickZone.None) continue;
                Color c = BandColor(g.Zone);
                for (int i = 0; i + 1 < path.Count; i++)
                {
                    Vector2 a = path[i], b = path[i + 1];
                    float len = Vector2.Distance(a, b);
                    if (len < 0.05f) continue;
                    int n = Mathf.Max(1, Mathf.CeilToInt(len / GimmickShape.SweepStep));
                    int start = -1;
                    for (int k = 0; k <= n; k++)
                    {
                        bool inside = Inside(g, Vector2.Lerp(a, b, (float)k / n));
                        if (inside && start < 0) start = k;
                        if ((!inside || k == n) && start >= 0)
                        {
                            int end = inside ? k : k - 1;
                            if (end > start)
                            {
                                Band(Vector2.Lerp(a, b, (float)start / n), Vector2.Lerp(a, b, (float)end / n), c);
                                LastBandColors.Add(c);
                            }
                            start = -1;
                        }
                    }
                }
            }
        }

        /// <summary>띠를 그릴 자리: 강 = 다리 구간 제외 · 안개 = 걷힌 자리 제외.</summary>
        bool Inside(GimmickInstance g, Vector2 p)
        {
            if (!g.Shape.Contains(p)) return false;
            if (g.Zone == GimmickZone.River) return layer.RiverAt(p) != null;
            if (g.Zone == GimmickZone.Fog) return layer.FogAt(p) != null;
            return true;
        }

        // ---------- 그리기(풀) ----------

        static Material DashMaterial
        {
            get
            {
                if (dashMaterial == null)
                {
                    var tex = new Texture2D(8, 2, TextureFormat.RGBA32, false);
                    var px = new Color[16];
                    for (int y = 0; y < 2; y++)
                        for (int x = 0; x < 8; x++)
                            px[y * 8 + x] = x < 5 ? Color.white : new Color(1f, 1f, 1f, 0f);
                    tex.SetPixels(px);
                    tex.wrapMode = TextureWrapMode.Repeat;
                    tex.filterMode = FilterMode.Point;
                    tex.Apply();
                    tex.hideFlags = HideFlags.DontSave;
                    dashMaterial = new Material(Shader.Find("Sprites/Default")) { mainTexture = tex };
                    dashMaterial.mainTextureScale = new Vector2(4f, 1f);
                    dashMaterial.hideFlags = HideFlags.DontSave;
                }
                return dashMaterial;
            }
        }

        static Material SolidMaterial
        {
            get
            {
                if (solidMaterial == null) solidMaterial = new Material(Shader.Find("Sprites/Default")) { hideFlags = HideFlags.DontSave };
                return solidMaterial;
            }
        }

        LineRenderer NewLine(string name, Material m, float width, int order, bool tile)
        {
            var go = new GameObject(name);
            go.transform.SetParent(root, false);
            var lr = go.AddComponent<LineRenderer>();
            lr.useWorldSpace = true;
            lr.sharedMaterial = m;
            lr.startWidth = lr.endWidth = width;
            lr.sortingOrder = order;
            lr.numCapVertices = tile ? 0 : 3;
            lr.textureMode = tile ? LineTextureMode.Tile : LineTextureMode.Stretch;
            return lr;
        }

        void Dash(List<Vector2> pts, Color c)
        {
            if (usedDash >= dashes.Count) dashes.Add(NewLine("Track", DashMaterial, 0.06f, 9, true));
            var lr = dashes[usedDash++];
            lr.positionCount = pts.Count;
            for (int i = 0; i < pts.Count; i++) lr.SetPosition(i, new Vector3(pts[i].x, pts[i].y, 0f));
            lr.startColor = lr.endColor = c;
            lr.enabled = true;
        }

        void Band(Vector2 a, Vector2 b, Color c)
        {
            if (usedBand >= bands.Count) bands.Add(NewLine("ZoneBand", SolidMaterial, 0.22f, 8, false));
            var lr = bands[usedBand++];
            lr.positionCount = 2;
            lr.SetPosition(0, new Vector3(a.x, a.y, 0f));
            lr.SetPosition(1, new Vector3(b.x, b.y, 0f));
            lr.startColor = lr.endColor = c;
            lr.enabled = true;
        }

        void Cut(Vector2 a, Vector2 b)
        {
            if (cut == null) cut = NewLine("BlockedCut", SolidMaterial, 0.13f, 11, false); // 조준선(10) 위
            cut.positionCount = 2;
            cut.SetPosition(0, new Vector3(a.x, a.y, 0f));
            cut.SetPosition(1, new Vector3(b.x, b.y, 0f));
            cut.startColor = cut.endColor = CutColor;
            cut.enabled = true;
            LastCut = true;
        }

        void Icon(Vector2 at, string text)
        {
            if (usedIcon >= icons.Count)
            {
                var tm = TextUtil.CreateWorldText(root, "", 0.3f, IconColor, 12, TextAnchor.MiddleLeft);
                tm.gameObject.name = "PreviewIcon";
                icons.Add(tm);
            }
            var t = icons[usedIcon++];
            t.text = text;
            t.transform.position = new Vector3(at.x + 0.4f, at.y - 0.3f, 0f); // 접점 오른쪽 아래(기믹 이름·조준선과 겹치지 않게)
            t.gameObject.SetActive(true);
            LastIcons.Add(text);
        }

        void Flush()
        {
            for (int i = usedDash; i < dashes.Count; i++) dashes[i].enabled = false;
            for (int i = usedBand; i < bands.Count; i++) bands[i].enabled = false;
            for (int i = usedIcon; i < icons.Count; i++) icons[i].gameObject.SetActive(false);
        }
    }
}