using System.Collections.Generic;
using UnityEngine;

namespace TKS
{
    /// <summary>
    /// 슬링샷 조작: 아군 유닛을 잡고(누름) 뒤로 당긴 뒤(드래그) 놓으면(드롭) 반대 방향으로 이동·공격.
    /// 유닛 탭(아군·적군) = 그 유닛의 사거리 표시(RangeIndicator) · 빈 곳 드래그 = 전장 스크롤 · 휠 = 줌 · 미니맵 탭 = 그 지점으로 이동.
    /// 버튼 없음. 결과 화면에서는 탭으로 계속. 추가 이동만 남았을 때 빈 곳 탭 = 건너뛰기.
    /// 궁병도 다른 병종과 같이 놓으면 바로 행동한다(조준 방향에 적이 없으면 목표점까지 이동 · PD 2026-11-04 2차 지시).
    /// </summary>
    public class SlingshotInput : MonoBehaviour
    {
        static readonly Color TargetFreeColor = Color.white;
        static readonly Color TargetHitColor = new Color(1f, 0.6f, 0.1f);
        static readonly Color ShotLineColor = new Color(1f, 0.92f, 0.6f, 0.95f);
        static readonly Color ShotLineFriendlyColor = new Color(1f, 0.2f, 0.2f, 0.95f);
        static readonly Color SplashAreaColor = new Color(0.7f, 0.45f, 1f, 0.22f);
        static readonly Color SplashAreaFriendlyColor = new Color(1f, 0.25f, 0.25f, 0.26f);

        BattleManager battle;
        Camera cam;
        BattleHUD hud;
        CameraController camCtrl;
        RangeIndicator range;

        Unit selected;
        bool dragging;
        bool panning;
        bool emptyPress;
        bool previewValid;
        Vector2 lastScreen;
        float panPixels;
        Vector2 currentTarget;

        LineRenderer aimLine;
        LineRenderer pullLine;
        LineRenderer shotLine;      // 궁병·책사 투사체 경로(쏘는 위치 → 첫 피격 지점 · PD 2026-11-05 #1087 ⑥)
        SpriteRenderer targetRing;
        SpriteRenderer splashArea;  // 책사 광역 원(중심 = 첫 피격 유닛 · #1087 ⑤)
        readonly List<Unit> highlighted = new List<Unit>();

        public Unit Selected
        {
            get { return selected; }
        }

        public bool ShotLineVisible
        {
            get { return shotLine != null && shotLine.enabled; }
        }

        public bool SplashVisible
        {
            get { return splashArea != null && splashArea.gameObject.activeSelf; }
        }

        /// <summary>책사 광역 원의 지름(월드) = strategistSplashRadius × 2 · 중심 = SplashCenter.</summary>
        public float SplashDiameter
        {
            get { return splashArea != null ? splashArea.transform.localScale.x : 0f; }
        }

        public Vector2 SplashCenter
        {
            get { return splashArea != null ? (Vector2)splashArea.transform.position : Vector2.zero; }
        }

        public RangeIndicator Range
        {
            get { return range; }
        }

        float TapPixels
        {
            get { return Mathf.Max(8f, Screen.height * 0.012f); }
        }

        public void Init(BattleManager b, Camera c, BattleHUD h, CameraController cc)
        {
            battle = b;
            cam = c;
            hud = h;
            camCtrl = cc;
            aimLine = MakeLine("AimLine", 0.08f, new Color(1f, 1f, 1f, 0.9f), 10);
            pullLine = MakeLine("PullLine", 0.035f, new Color(1f, 1f, 1f, 0.35f), 9);
            shotLine = MakeLine("ShotLine", 0.05f, ShotLineColor, 10);
            targetRing = ProceduralSprites.NewSprite(transform, "TargetRing", ProceduralSprites.Ring, Color.white, 0.7f, 11);
            targetRing.enabled = false;
            splashArea = ProceduralSprites.NewSprite(transform, "SplashArea", ProceduralSprites.Circle, SplashAreaColor, 1f, -8);
            splashArea.gameObject.SetActive(false);

            var rgo = new GameObject("RangeIndicator");
            rgo.transform.SetParent(transform, false);
            range = rgo.AddComponent<RangeIndicator>();
            range.Init(b.Config.archerRangeRatio);
        }

        LineRenderer MakeLine(string name, float width, Color color, int order)
        {
            var go = new GameObject(name);
            go.transform.SetParent(transform, false);
            var lr = go.AddComponent<LineRenderer>();
            lr.useWorldSpace = true;
            lr.positionCount = 2;
            lr.startWidth = width;
            lr.endWidth = width;
            lr.material = new Material(Shader.Find("Sprites/Default"));
            lr.startColor = color;
            lr.endColor = color;
            lr.sortingOrder = order;
            lr.numCapVertices = 4;
            lr.enabled = false;
            return lr;
        }

        Vector2 ScreenToWorld(Vector2 screen)
        {
            Vector3 p = screen;
            p.z = -cam.transform.position.z;
            return cam.ScreenToWorldPoint(p);
        }

        void Update()
        {
            if (battle == null || battle.Config == null) return;
            var phase = battle.Phase;
            if (phase == BattlePhase.StageClear || phase == BattlePhase.Defeat)
            {
                if (Input.GetMouseButtonDown(0)) battle.ContinueAfterResult();
                return;
            }

            Vector2 screen = Input.mousePosition;
            if (Input.GetMouseButtonDown(0)) OnPress(screen);
            else if (Input.GetMouseButton(0))
            {
                if (dragging) OnDrag(ScreenToWorld(screen));
                else if (panning) OnPan(screen);
            }
            if (Input.GetMouseButtonUp(0)) OnRelease(screen);

            float wheel = Input.mouseScrollDelta.y;
            if (Mathf.Abs(wheel) > 0.01f && camCtrl != null) camCtrl.Zoom(1f - wheel * 0.1f);
        }

        void OnPress(Vector2 screen)
        {
            lastScreen = screen;
            panPixels = 0f;
            dragging = false;
            panning = false;
            emptyPress = false;
            previewValid = false;

            Vector2 mapWorld;
            if (hud != null && camCtrl != null && hud.TryMinimapTap(screen, out mapWorld))
            {
                camCtrl.FocusOn(mapWorld);
                return;
            }

            Vector2 w = ScreenToWorld(screen);
            var u = battle.UnitNear(w, Faction.Player);
            if (u == null) u = battle.UnitNear(w, null); // 적 유닛 터치 = 적의 사거리 표시
            Select(u);
            if (u != null && battle.CanAct(u))
            {
                dragging = true;
                if (u.View != null) u.View.SetAiming(true);
            }
            else if (u == null)
            {
                panning = true;
                emptyPress = true;
            }
        }

        void OnPan(Vector2 screen)
        {
            Vector2 d = screen - lastScreen;
            lastScreen = screen;
            panPixels += d.magnitude;
            if (panPixels > TapPixels && camCtrl != null)
            {
                camCtrl.PanBy(-d * camCtrl.WorldUnitsPerPixel);
            }
        }

        void OnDrag(Vector2 w)
        {
            if (selected == null) return;
            Vector2 pull = w - selected.Position;
            Vector2 launch = -pull;
            float mag = launch.magnitude;
            if (mag < battle.Config.minDragDistance)
            {
                HidePreview();
                previewValid = false;
                return;
            }
            if (mag > selected.SlingMaxDistance) launch = launch / mag * selected.SlingMaxDistance;
            currentTarget = battle.Board.ClampInside(selected.Position + launch, selected.Radius);
            previewValid = true;
            ShowPreview(selected, currentTarget, w);
        }

        void OnRelease(Vector2 screen)
        {
            if (dragging && selected != null && previewValid && battle.CanAct(selected))
            {
                var t = currentTarget;
                var u = selected;
                HidePreview();
                if (u.View != null) u.View.SetAiming(false);
                Select(null);
                battle.RequestPlayerAction(u, t);
            }
            else if (emptyPress && panPixels <= TapPixels)
            {
                battle.OnEmptyTap();
            }
            else
            {
                HidePreview();
                if (dragging && selected != null && selected.View != null) selected.View.SetAiming(false);
            }
            dragging = false;
            panning = false;
            emptyPress = false;
            previewValid = false;
        }

        /// <summary>유닛 선택(아군·적군 · null = 해제): 선택 링 + HUD 정보 + 사거리 표시(궁병은 도넛 · 범위 안 적 유무로 색).</summary>
        public void Select(Unit u)
        {
            if (selected != null && selected.View != null)
            {
                selected.View.SetSelected(false);
                selected.View.SetAiming(false);
            }
            selected = u;
            if (u != null && u.View != null) u.View.SetSelected(true);
            if (hud != null) hud.SetSelected(u);
            if (range != null)
            {
                range.Show(u);
                if (u != null && UnitTypeInfo.IsRanged(u.Type)) range.SetArcherReachable(battle.AnyEnemyWithinArcherReach(u));
            }
        }

        /// <summary>조준 표시(자동 플레이 캡처에서도 호출). 반환 = 공격 예정 적 수.</summary>
        public int ShowPreview(Unit u, Vector2 target, Vector2? pointer)
        {
            aimLine.enabled = true;
            aimLine.SetPosition(0, new Vector3(u.Position.x, u.Position.y, 0f));
            aimLine.SetPosition(1, new Vector3(target.x, target.y, 0f));
            if (pointer.HasValue)
            {
                pullLine.enabled = true;
                pullLine.SetPosition(0, new Vector3(u.Position.x, u.Position.y, 0f));
                pullLine.SetPosition(1, new Vector3(pointer.Value.x, pointer.Value.y, 0f));
            }
            else
            {
                pullLine.enabled = false;
            }
            targetRing.enabled = true;
            targetRing.transform.position = new Vector3(target.x, target.y, 0f);

            bool moveOnly = u.BonusMoveAvailable;
            var finalHit = moveOnly ? null : Combat.EnemyAtPoint(u, target, battle.Config.finalHitTolerance);
            targetRing.color = finalHit != null ? TargetHitColor : TargetFreeColor;
            targetRing.transform.localScale = finalHit != null ? new Vector3(0.9f, 0.9f, 1f) : new Vector3(0.7f, 0.7f, 1f);

            ClearHighlights();
            var shot = battle.Resolver.PreviewShot(u, target, moveOnly);
            if (shot != null)
            {
                return ShowShot(u, shot);
            }
            HideShot();
            foreach (var e in battle.Resolver.PredictTargets(u, target, moveOnly)) Highlight(e, false);
            return highlighted.Count;
        }

        /// <summary>
        /// 궁병·책사 조준(PD 2026-11-05 #1087 ⑤⑥): 화살 경로선(쏘는 위치 → 첫 피격 지점) + 첫 피격 유닛 강조(같은 편이면 붉게)
        /// · 책사 = 맞을 자리 광역 원 + 휩쓸릴 유닛 강조(같은 편 붉게). 반환 = 맞을 상대 유닛 수.
        /// </summary>
        int ShowShot(Unit u, ActionResolver.ShotPlan shot)
        {
            if (!shot.Fires)
            {
                HideShot();
                return 0;
            }
            bool friendlyCenter = shot.Hit != null && shot.Hit.Faction == u.Faction;
            shotLine.enabled = true;
            shotLine.startColor = shotLine.endColor = friendlyCenter ? ShotLineFriendlyColor : ShotLineColor;
            shotLine.SetPosition(0, new Vector3(shot.From.x, shot.From.y, 0f));
            shotLine.SetPosition(1, new Vector3(shot.To.x, shot.To.y, 0f));
            int foes = 0;
            if (shot.Hit != null)
            {
                Highlight(shot.Hit, friendlyCenter);
                if (!friendlyCenter) foes++;
            }

            bool splash = u.Type == UnitType.Strategist && shot.Hit != null;
            if (splash)
            {
                bool anyFriendly = friendlyCenter;
                foreach (var s in shot.Splash)
                {
                    bool friendly = s.Faction == u.Faction;
                    Highlight(s, friendly);
                    if (friendly) anyFriendly = true;
                    else foes++;
                }
                float d = battle.Config.strategistSplashRadius * 2f;
                splashArea.transform.position = new Vector3(shot.Hit.Position.x, shot.Hit.Position.y, 0f);
                splashArea.transform.localScale = new Vector3(d, d, 1f);
                splashArea.color = anyFriendly ? SplashAreaFriendlyColor : SplashAreaColor;
            }
            if (splashArea.gameObject.activeSelf != splash) splashArea.gameObject.SetActive(splash);
            return foes;
        }

        void HideShot()
        {
            shotLine.enabled = false;
            splashArea.gameObject.SetActive(false);
        }

        void Highlight(Unit e, bool friendly)
        {
            if (e == null || highlighted.Contains(e)) return;
            if (e.View != null) e.View.SetHighlight(true, friendly);
            highlighted.Add(e);
        }

        public void HidePreview()
        {
            aimLine.enabled = false;
            pullLine.enabled = false;
            targetRing.enabled = false;
            HideShot();
            ClearHighlights();
        }

        void ClearHighlights()
        {
            foreach (var h in highlighted)
            {
                if (h != null && h.View != null) h.View.SetHighlight(false);
            }
            highlighted.Clear();
        }
    }
}