using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using CounterDrone.Core.Algorithms;
using CounterDrone.Core.Models;
using CounterDrone.Core.Services;
using SQLite;

namespace CounterDrone.Core.Simulation
{
    /// <summary>仿真引擎 — 纯执行器，接收发射计划按时间表执行</summary>
    public class SimulationEngine
    {
        private readonly IScenarioService _scenarioService;
        private readonly FrameDataStore _frameStore;
        private readonly IDamageModel _damageModel;
        private readonly IPathProvider _paths;

        public SimulationState State { get; private set; } = SimulationState.Idle;
        public int FrameIndex { get; private set; }
        public float SimulationTime { get; private set; }
        public float TimeScale { get; set; } = 1f;
        private float _tickInterval;

        public IReadOnlyList<DroneEntity> Drones => _drones;
        public IReadOnlyList<CloudEntity> Clouds => _clouds;
        public IReadOnlyList<MunitionEntity> Munitions => _munitions;
        public IReadOnlyList<SimEvent> Events => _allEvents;

        public event Action<MunitionEntity> OnMunitionLaunched;
        public event Action<CloudEntity> OnCloudGenerated;
        public event Action<DroneEntity> OnDroneDestroyed;
        public event Action<DroneEntity> OnDroneReachedTarget;
        public event Action<DroneEntity, ControlZoneEntity> OnZoneIntruded;
        public event Action OnSimulationEnded;

        private List<DroneEntity> _drones = new();
        private List<PlatformEntity> _platforms = new();
        private List<MunitionEntity> _munitions = new();
        private List<CloudEntity> _clouds = new();
        private List<ControlZoneEntity> _zones = new();
        private CombatScene _scene = new();
        private float _disperseHeight;
        private AmmunitionSpec _ammoSpec = new();
        private int _tickRate = 20;
        private readonly List<FireEvent> _fireSchedule = new();
        private int _nextFireIndex;
        private readonly List<SimEvent> _allEvents = new();
        private SQLiteConnection _frameDb = null!;
        private string _taskId = string.Empty;
        private readonly IDefensePlanner _planner;
        private int _entityCounter;

        public SimulationEngine(IScenarioService scenarioService, FrameDataStore frameStore,
            IDamageModel damageModel, IPathProvider paths, IDefensePlanner? planner = null)
        {
            _scenarioService = scenarioService;
            _frameStore = frameStore;
            _damageModel = damageModel;
            _paths = paths;
            _planner = planner ?? new DefaultDefensePlanner(new List<AmmunitionSpec>());
        }

        public void SetFireSchedule(List<FireEvent> schedule)
        {
            _fireSchedule.Clear();
            _fireSchedule.AddRange(schedule.OrderBy(f => f.FireTime));
            _nextFireIndex = 0;
        }

        public void Initialize(string taskId)
        {
            _taskId = taskId;
            var config = _scenarioService.GetTaskDetail(taskId);
            if (config == null) throw new InvalidOperationException("Task not found");

            _scene = config.Scene;
            _disperseHeight = (float)config.Cloud.DisperseHeight;
            _tickRate = config.Task.TickRate;
            _tickInterval = 1.0f / _tickRate;

            using (var ammoDb = new SQLiteConnection(_paths.GetMainDbPath()))
                _ammoSpec = ammoDb.Table<AmmunitionSpec>()
                    .FirstOrDefault(a => a.AerosolType == config.Cloud.AerosolType)
                    ?? DefaultAmmunition.GetByType((AerosolType)config.Cloud.AerosolType);

            _drones.Clear();
            foreach (var target in config.Targets)
            {
                var route = config.Routes.FirstOrDefault(r => r.GroupId == target.GroupId);
                var wps = config.WaypointGroups.GetValueOrDefault(target.GroupId, new List<Waypoint>());
                if (route == null || wps.Count == 0) continue;
                var mode = (FormationMode)route.FormationMode;
                var spacing = (float)route.FormationSpacing;
                for (int i = 0; i < target.Quantity; i++)
                    _drones.Add(new DroneEntity($"drone_{++_entityCounter}", target.GroupId,
                        target, wps, i, spacing, mode));
            }

            _platforms.Clear();
            foreach (var equip in config.Equipment)
                if (equip.EquipmentRole != (int)EquipmentRole.Detection)
                    for (int i = 0; i < equip.Quantity; i++)
                        _platforms.Add(new PlatformEntity($"plat_{++_entityCounter}", equip));

            _zones.Clear();
            foreach (var z in config.ControlZones)
                _zones.Add(new ControlZoneEntity(z.Id, z.Name, z.VerticesJson,
                    (float)z.MinAltitude, (float)z.MaxAltitude));

            _munitions.Clear();
            _clouds.Clear();
            _allEvents.Clear();
            FrameIndex = 0;
            SimulationTime = 0;
            _entityCounter = 0;
            _nextFireIndex = 0;

            // 自动从 Planner 生成发射计划
            if (_fireSchedule.Count == 0)
            {
                var fireUnits = BuildFireUnits(config);
                var threats = BuildDroneGroups(config);
                if (fireUnits.Count > 0 && threats.Count > 0)
                {
                    using (var ammoDb = new SQLiteConnection(_paths.GetMainDbPath()))
                    {
                        var catalog = new List<AmmunitionSpec>(ammoDb.Table<AmmunitionSpec>().ToList());
                        if (catalog.Count == 0)
                            catalog = DefaultAmmunition.GetAll();
                        var planner = new DefaultDefensePlanner(catalog);
                        var result = planner.Plan(fireUnits, threats, _scene);
                        SetFireSchedule(result.Best.MergedSchedule);
                    }
                }
            }

            _frameDb = _frameStore.CreateOrOpen(_taskId);
            State = SimulationState.Running;
        }

        public SimulationFrameResult Tick(float deltaTime)
        {
            if (State != SimulationState.Running)
                return new SimulationFrameResult { State = State, FrameIndex = FrameIndex, SimulationTime = SimulationTime };

            var scaledDt = deltaTime * TimeScale;
            SimulationTime += scaledDt;
            FrameIndex++;
            var frameEvents = new List<SimEvent>();

            // 1. 按发射计划执行
            while (_nextFireIndex < _fireSchedule.Count && _fireSchedule[_nextFireIndex].FireTime <= SimulationTime)
            {
                var fe = _fireSchedule[_nextFireIndex++];
                var platform = _platforms.Count > fe.PlatformIndex ? _platforms[fe.PlatformIndex] : null;
                if (platform == null) continue;

                if (platform.PlatformType == Models.PlatformType.AirBased && platform.Ready)
                {
                    // 空基：下令飞往投放点（投放点 = 目标正上方，ReleaseAltitude 高度）
                    var releaseAlt = platform.ReleaseAltitude > 0 ? platform.ReleaseAltitude : _disperseHeight;
                    platform.CommandFlyTo(fe.TargetX, releaseAlt, fe.TargetZ);
                }
                else if (platform.Ready)
                {
                    // 地基：直接发射
                    platform.Release();
                    var m = new MunitionEntity($"mun_{++_entityCounter}",
                        platform.PlatformType ?? Models.PlatformType.GroundBased,
                        platform.AerosolType ?? Models.AerosolType.InertGas,
                        platform.PosX, platform.PosY, platform.PosZ,
                        fe.TargetX, fe.TargetY, fe.TargetZ, fe.MuzzleVelocity, _disperseHeight);
                    _munitions.Add(m);
                    OnMunitionLaunched?.Invoke(m);
                    frameEvents.Add(new SimEvent { Type = SimEventType.MunitionLaunched, OccurredAt = SimulationTime, SourceId = platform.Id, Description = $"计划发射 {m.Id}" });
                }
            }

            // 1b. 空基平台到达投放点 → 投弹
            foreach (var platform in _platforms.Where(p => p.CanRelease))
            {
                var (cvx, cvy, cvz) = platform.CurrentVelocity;
                platform.Release();
                var m = new MunitionEntity($"mun_{++_entityCounter}",
                    Models.PlatformType.AirBased,
                    platform.AerosolType ?? Models.AerosolType.InertGas,
                    platform.PosX, platform.PosY, platform.PosZ,
                    platform.PosX, _disperseHeight, platform.PosZ,
                    0f, _disperseHeight,
                    cvx, cvy, cvz);
                _munitions.Add(m);
                OnMunitionLaunched?.Invoke(m);
                frameEvents.Add(new SimEvent { Type = SimEventType.MunitionLaunched, OccurredAt = SimulationTime, SourceId = platform.Id, Description = $"空基投放 {m.Id}" });
            }

            // 2. 弹药飞行 → 云团生成
            foreach (var m in _munitions.ToList())
            {
                m.Update(scaledDt);
                if (m.HasArrived)
                {
                    var disp = AlgorithmFactory.Create<ICloudDispersionModel>();
                    disp.Initialize(_ammoSpec, _scene, new Algorithms.Vector3(m.TargetX, m.TargetY, m.TargetZ), SimulationTime);
                    var cloud = new CloudEntity($"cloud_{++_entityCounter}", m.AerosolType, disp, SimulationTime);
                    _clouds.Add(cloud);
                    _munitions.Remove(m);
                    OnCloudGenerated?.Invoke(cloud);
                    frameEvents.Add(new SimEvent { Type = SimEventType.CloudGenerated, OccurredAt = SimulationTime, Description = "云团生成" });
                }
            }

            // 3. 云团演化
            foreach (var c in _clouds.ToList())
            {
                c.Tick(scaledDt, (float)_scene.WindSpeed, (WindDirection)_scene.WindDirection);
                if (c.IsDissipated) _clouds.Remove(c);
            }

            // 4. 毁伤判定
            foreach (var drone in _drones.Where(d => d.Status == DroneStatus.Flying))
            {
                foreach (var cloud in _clouds)
                {
                    if (cloud.ContainsPoint(drone.PosX, drone.PosY, drone.PosZ))
                    {
                        drone.ExposureTime += scaledDt;
                        var dmg = _damageModel.CalculateDamage(drone.TargetType, drone.PowerType, cloud.AerosolType, cloud.Dispersion.CoreDensity, drone.ExposureTime, scaledDt);
                        drone.ApplyDamage(dmg);
                        if (drone.Status == DroneStatus.Destroyed)
                        {
                            OnDroneDestroyed?.Invoke(drone);
                            frameEvents.Add(new SimEvent { Type = SimEventType.DroneDestroyed, OccurredAt = SimulationTime, TargetId = drone.Id, Description = $"无人机 {drone.Id} 被摧毁" });
                        }
                    }
                }
            }

            // 5. 无人机移动
            foreach (var drone in _drones.Where(d => d.Status == DroneStatus.Flying))
            {
                drone.Update(scaledDt, (float)_scene.WindSpeed, (WindDirection)_scene.WindDirection);
                if (drone.Status == DroneStatus.ReachedTarget)
                {
                    OnDroneReachedTarget?.Invoke(drone);
                    frameEvents.Add(new SimEvent { Type = SimEventType.DroneReachedTarget, OccurredAt = SimulationTime, SourceId = drone.Id, Description = "到达攻击目标" });
                }
            }

            // 6. 平台冷却
            foreach (var p in _platforms) p.Update(scaledDt);

            // 7. 管控区域
            foreach (var drone in _drones.Where(d => d.Status == DroneStatus.Flying))
            {
                foreach (var zone in _zones)
                {
                    if (zone.ContainsPoint(drone.PosX, drone.PosY, drone.PosZ))
                    {
                        drone.MarkZoneIntruded();
                        OnZoneIntruded?.Invoke(drone, zone);
                        frameEvents.Add(new SimEvent { Type = SimEventType.ZoneIntruded, OccurredAt = SimulationTime, SourceId = drone.Id, TargetId = zone.Id, Description = $"侵入 {zone.Name}" });
                    }
                }
            }

            // 8. 结束判定
            if (_drones.All(d => d.Status != DroneStatus.Flying))
            {
                State = SimulationState.Completed;
                OnSimulationEnded?.Invoke();
                frameEvents.Add(new SimEvent { Type = SimEventType.SimulationEnd, OccurredAt = SimulationTime });
            }

            _allEvents.AddRange(frameEvents);

            var snapshots = CollectSnapshots();
            _frameStore.WriteFrame(_frameDb, _taskId, FrameIndex, SimulationTime, snapshots);
            _frameDb.Commit();

            return new SimulationFrameResult { EntitySnapshots = snapshots, NewEvents = frameEvents, State = State, FrameIndex = FrameIndex, SimulationTime = SimulationTime };
        }

        public void Pause() { if (State == SimulationState.Running) State = SimulationState.Paused; }
        public void Resume() { if (State == SimulationState.Paused) State = SimulationState.Running; }
        public void Stop() { State = SimulationState.Stopped; _frameDb?.Close(); }

        private static List<FireUnit> BuildFireUnits(TaskFullConfig config)
        {
            var units = new List<FireUnit>();
            int idx = 0;
            foreach (var eq in config.Equipment.Where(e => e.EquipmentRole == (int)EquipmentRole.LaunchPlatform))
            {
                int qty = Math.Max(1, eq.Quantity);
                for (int i = 0; i < qty; i++)
                {
                    units.Add(new FireUnit
                    {
                        Id = $"fu{idx++}",
                        Type = (PlatformType)(eq.PlatformType ?? (int)PlatformType.GroundBased),
                        Position = new Algorithms.Vector3((float)eq.PositionX + i * 50, (float)eq.PositionY, (float)eq.PositionZ),
                        CruiseSpeed = (float)(eq.CruiseSpeed ?? 55f),
                        ReleaseAltitude = (float)(eq.ReleaseAltitude ?? 1000f),
                        MuzzleVelocity = (float)(eq.MuzzleVelocity ?? 800f),
                        TotalMunitions = eq.MunitionCount ?? 1,
                        AmmoTypes = new List<AerosolType> { (AerosolType)(eq.AerosolType ?? 0) },
                        Cooldown = (float)eq.Cooldown,
                    });
                }
            }
            return units;
        }

        private static List<DroneGroup> BuildDroneGroups(TaskFullConfig config)
        {
            var groups = new List<DroneGroup>();
            foreach (var t in config.Targets)
            {
                var route = config.Routes.FirstOrDefault(r => r.GroupId == t.GroupId);
                var wps = config.WaypointGroups.GetValueOrDefault(t.GroupId, new List<Waypoint>());
                groups.Add(new DroneGroup
                {
                    GroupId = t.GroupId,
                    Target = t,
                    Route = route ?? new RoutePlan(),
                    Waypoints = wps,
                });
            }
            return groups;
        }

        private List<EntitySnapshot> CollectSnapshots()
        {
            var list = new List<EntitySnapshot>();
            foreach (var d in _drones)
                list.Add(new EntitySnapshot { EntityId = d.Id, EntityType = Models.EntityType.Drone, PosX = d.PosX, PosY = d.PosY, PosZ = d.PosZ, StateData = JsonSerializer.Serialize(new { damageStage = (int)_damageModel.GetDamageStage(1 - d.Hp), hp = d.Hp }) });
            foreach (var p in _platforms.Where(p => p.PlatformType == Models.PlatformType.AirBased))
                list.Add(new EntitySnapshot { EntityId = p.Id, EntityType = Models.EntityType.Platform, PosX = p.PosX, PosY = p.PosY, PosZ = p.PosZ, StateData = JsonSerializer.Serialize(new { state = p.State.ToString() }) });
            foreach (var c in _clouds)
                list.Add(new EntitySnapshot { EntityId = c.Id, EntityType = Models.EntityType.Cloud, PosX = c.Dispersion.Center.X, PosY = c.Dispersion.Center.Y, PosZ = c.Dispersion.Center.Z, StateData = JsonSerializer.Serialize(new { radius = c.Dispersion.Radius, opacity = c.Dispersion.Particles.Opacity, phase = c.Dispersion.Phase, elapsed = c.Dispersion.Elapsed }) });
            return list;
        }
    }
}