using System;
using System.Collections.Generic;
using System.Linq;
using CounterDrone.Core.Models;

namespace CounterDrone.Core.Algorithms
{
    public class DefaultDefenseAdvisor : IDefenseAdvisor
    {
        private readonly List<AmmunitionSpec> _ammoCatalog;

        public DefaultDefenseAdvisor(List<AmmunitionSpec> ammoCatalog)
        {
            _ammoCatalog = ammoCatalog ?? new List<AmmunitionSpec>();
        }

        private static readonly Dictionary<PowerType, AerosolType> MatchTable = new()
        {
            { PowerType.Electric, AerosolType.InertGas },
            { PowerType.Piston,   AerosolType.InertGas },
            { PowerType.Jet,      AerosolType.ActiveMaterial },
        };

        public DefenseRecommendation Recommend(ThreatProfile threat)
        {
            var result = new DefenseRecommendation
            {
                Best = new DefenseSolution(),
                Critical = new DefenseSolution(),
            };

            // ===== 输入校验 =====
            if (threat.Targets.Count == 0)
            {
                result.Best.SummaryRationale = "失败：未配置威胁目标";
                return result;
            }
            if (threat.Waypoints.Count < 2)
            {
                result.Best.SummaryRationale = "失败：需要至少两个航路点";
                return result;
            }

            var target = threat.Targets[0];
            if (target.TypicalSpeed <= 0)
            {
                result.Best.SummaryRationale = "失败：目标速度为 0";
                return result;
            }

            // ===== Step A：气溶胶选型 =====
            var powerType = (PowerType)target.PowerType;
            var aerosolType = MatchTable.TryGetValue(powerType, out var match)
                ? match : AerosolType.InertGas;

            var ammo = _ammoCatalog.FirstOrDefault(a => a.AerosolType == (int)aerosolType);
            if (ammo == null)
            {
                result.Best.SummaryRationale = $"失败：弹药库中未找到 {aerosolType} 类型的弹药规格";
                return result;
            }

            var rationale = powerType switch
            {
                PowerType.Electric or PowerType.Piston =>
                    $"{powerType}发动机依赖氧气，推荐惰性气体窒息方案",
                PowerType.Jet =>
                    $"{powerType}发动机高温表面可触发活性材料爆燃反应",
                _ => "默认推荐惰性气体方案",
            };

            // ===== Step B：时空交汇优化 =====
            var start = ToV3(threat.Waypoints[0]);
            var end = ToV3(threat.Waypoints[^1]);
            var mid = new Vector3((start.X + end.X) / 2f, (start.Y + end.Y) / 2f, (start.Z + end.Z) / 2f);
            var routeLength = start.DistanceTo(end);
            var avgSpeed = (float)target.TypicalSpeed / 3.6f;
            var totalFlightTime = routeLength / avgSpeed;

            if (routeLength < 100)
            {
                result.Best.SummaryRationale = "失败：航路太短（<100m）";
                return result;
            }

            // 弹药参数
            var initialR = (float)ammo.InitialRadius;
            var maxDur = (float)ammo.MaxDuration;

            // 无人机穿过单个云团的时间
            var crossTime = (2f * initialR) / avgSpeed;
            var neededExposure = aerosolType == AerosolType.ActiveMaterial ? 2f : 6f;
            var spacing = initialR * 1.5f; // 云团间隔

            // 有效覆盖距离 = 间距×(N-1) + 直径，需 ≥ 所需暴露时间 × 速度
            var requiredCoverage = neededExposure * avgSpeed;
            var roundsNeeded = Math.Max(1,
                (int)Math.Ceiling((requiredCoverage - 2f * initialR) / spacing) + 1);

            // 实际有效暴露时间
            var actualCoverage = spacing * (roundsNeeded - 1) + 2f * initialR;
            var actualExposure = actualCoverage / avgSpeed;
            var prob = Math.Min(0.95f, actualExposure / neededExposure);

            // 多轮次云团：沿航路等距分布
            var cloudSalvo = new List<CloudDispersal>();
            for (int i = 0; i < roundsNeeded; i++)
            {
                var offset = (i - (roundsNeeded - 1) / 2f) * spacing;
                cloudSalvo.Add(new CloudDispersal
                {
                    AerosolType = (int)aerosolType,
                    PositionX = mid.X + offset,
                    PositionY = mid.Y,
                    PositionZ = mid.Z,
                    DisperseHeight = (float)target.TypicalAltitude,
                    TriggerMode = (int)TriggerMode.Time,
                    Duration = (int)maxDur,
                    InitialScale = ammo.InitialVolume,
                    ReleaseMode = (int)ReleaseMode.Single,
                    Source = "Algorithm",
                    PositionMode = (int)PositionMode.AlgorithmRecommended,
                    RecommendedTiming = totalFlightTime / 2f,
                });
            }

            // 平台部署：假设齐射（同时发射），每门炮打一发后冷却 5s
            // 需要 roundsNeeded 门炮同时发射
            var gunCount = roundsNeeded;
            var platforms = new List<RecommendedPlatform>();
            for (int i = 0; i < gunCount; i++)
                platforms.Add(new RecommendedPlatform
                {
                    Type = PlatformType.GroundBased,
                    Position = new Vector3(mid.X + i * 50, 0, 50),
                    Quantity = 1,
                    MunitionCount = 1,
                    CoverageVolume = (float)ammo.InitialVolume,
                    Cooldown = 5f,
                    MuzzleVelocity = 800f,
                });

            result.Best = new DefenseSolution
            {
                RecommendedAerosolType = aerosolType,
                AerosolRationale = rationale,
                RecommendedCloud = cloudSalvo[0],
                CloudSalvo = cloudSalvo,
                Platforms = platforms,
                Detections = new List<RecommendedDetection>
                {
                    new RecommendedDetection
                    {
                        Position = new Vector3(mid.X, mid.Y, 0),
                        DetectionRadius = Math.Max(3000f, routeLength * 0.4f),
                        Quantity = 1,
                    }
                },
                InterceptProbability = prob,
                SummaryRationale = $"{aerosolType}方案，{roundsNeeded}发，预计拦截概率 {prob:P0}",
            };

            result.Critical = new DefenseSolution
            {
                RecommendedAerosolType = aerosolType,
                RecommendedCloud = new CloudDispersal
                {
                    AerosolType = (int)aerosolType,
                    PositionX = start.X + (end.X - start.X) * 0.25f,
                    PositionY = start.Y,
                    PositionZ = start.Z,
                    DisperseHeight = (float)target.TypicalAltitude,
                    Duration = (int)maxDur,
                    Source = "Algorithm",
                    PositionMode = (int)PositionMode.AlgorithmRecommended,
                    RecommendedTiming = totalFlightTime * 0.25f,
                },
                Platforms = platforms,
                InterceptProbability = prob * 0.3f,
                SummaryRationale = $"临界方案：拦截概率仅 {prob * 0.3f:P0}",
            };

            return result;
        }

        private static Vector3 ToV3(Waypoint wp) => new((float)wp.PosX, (float)wp.PosY, (float)wp.PosZ);
    }
}