using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using CounterDrone.Core;
using CounterDrone.Core.Algorithms;
using CounterDrone.Core.Models;
using CounterDrone.Core.Repository;
using CounterDrone.Core.Services;
using CounterDrone.Core.Simulation;
using Xunit;

namespace CounterDrone.Core.Tests
{
    /// <summary>仿真引擎基础单元测试（不含集成场景，集成场景见 FullPipelineTests）</summary>
    public class SimulationEngineTests : IDisposable
    {
        private readonly string _testDir;
        private readonly SimulationEngine _engine;
        private readonly IScenarioService _scenarioService;
        private readonly SQLite.SQLiteConnection _mainDb;
        private string _scenarioId = string.Empty;

        public SimulationEngineTests()
        {
            _testDir = Path.Combine(Path.GetTempPath(), $"cd_test_{Guid.NewGuid():N}");
            var paths = new TestPathProvider(_testDir);
            var dbManager = new DatabaseManager(paths);
            _mainDb = dbManager.OpenMainDb();

            _scenarioService = new ScenarioService(
                new ScenarioRepository(_mainDb), new CombatSceneRepository(_mainDb),
                new ControlZoneRepository(_mainDb), new ScenarioDroneRepository(_mainDb),
                new ScenarioUnitRepository(_mainDb), new CloudDispersalRepository(_mainDb),
                new RoutePlanRepository(_mainDb), new WaypointRepository(_mainDb));

            _engine = new SimulationEngine(_scenarioService, new FrameDataStore(paths),
                new DamageModelRouter(), paths, new DefensePlanner(TestData.Ammo, TestPlannerConfig.Instance));
        }

        public void Dispose()
        {
            _engine.Stop();
            _mainDb?.Close();
            if (Directory.Exists(_testDir)) Directory.Delete(_testDir, true);
        }

        private void SetupScenario()
        {
            var scenario = _scenarioService.CreateScenario("Test", "");
            _scenarioId = scenario.Id;
            _scenarioService.SaveScene(_scenarioId, new CombatScene { WindSpeed = 0 });
            _scenarioService.SaveScenarioDrone(_scenarioId, TestData.CreateScenarioDrone("default", 1));
            _scenarioService.SaveDeployment(_scenarioId, new List<ScenarioUnit>
            {
                TestData.CreateScenarioUnit(0, 0, 0, 0, 1),
            });
            _scenarioService.SaveCloudDispersal(_scenarioId, new CloudDispersal
            {
                AerosolType = (int)AerosolType.InertGas,
                DisperseHeight = 300,
                Duration = 60,
                RecommendedTiming = 10,
                PositionX = 1000,
                PositionY = 300,
                PositionZ = 0,
                PositionMode = (int)PositionMode.AlgorithmRecommended,
            });
            _scenarioService.SaveRoute(_scenarioId, "default", new RoutePlan { FormationMode = (int)FormationMode.Single },
                new List<Waypoint>
                {
                    new Waypoint { PosX = 0, PosY = 300, PosZ = 0, Altitude = 300, Speed = 60 },
                    new Waypoint { PosX = 10000, PosY = 300, PosZ = 0, Altitude = 300, Speed = 60 },
                });
        }

        [Fact]
        public void Initialize_LoadsEntities()
        {
            SetupScenario();
            _engine.Initialize(_scenarioId);
            Assert.Single(_engine.Drones);
            Assert.Equal(SimulationState.Running, _engine.State);
        }

        [Fact]
        public void Tick_DroneMoves()
        {
            SetupScenario();
            _engine.Initialize(_scenarioId);
            _engine.Tick(1f / 20f);
            Assert.True(_engine.Drones[0].PosX > 0);
        }

        [Fact]
        public void PauseAndResume()
        {
            SetupScenario();
            _engine.Initialize(_scenarioId);
            _engine.Pause();
            Assert.Equal(SimulationState.Paused, _engine.State);

            var result = _engine.Tick(1f);
            Assert.Equal(SimulationState.Paused, result.State);

            _engine.Resume();
            Assert.Equal(SimulationState.Running, _engine.State);
        }

        [Fact]
        public void Stop_ClosesGracefully()
        {
            SetupScenario();
            _engine.Initialize(_scenarioId);
            _engine.Tick(1f / 20f);
            _engine.Stop();
            Assert.Equal(SimulationState.Stopped, _engine.State);
        }

        [Fact]
        public void FrameData_IsWritten()
        {
            SetupScenario();
            _engine.Initialize(_scenarioId);
            for (int i = 0; i < 10; i++) _engine.Tick(1f / 20f);
            _engine.Stop(); // 触发 Flush

            var framePath = Path.Combine(_testDir, "frames", $"{_scenarioId}.db");
            Assert.True(File.Exists(framePath));
        }

        // ═══════════════════════════════════════
        // T4.4 实时探测 — TargetDetected 事件
        // ═══════════════════════════════════════

        private void SetupScenarioWithDetection()
        {
            var scenario = _scenarioService.CreateScenario("Detect", "");
            _scenarioId = scenario.Id;
            _scenarioService.SaveScene(_scenarioId, new CombatScene { WindSpeed = 0, Visibility = 10000 });
            _scenarioService.SaveScenarioDrone(_scenarioId, TestData.CreateScenarioDrone("w1", 1));
            // 探测设备在 (5000, 0, 0)，雷达 3000m，无角度/高度限制
            _scenarioService.SaveDeployment(_scenarioId, new List<ScenarioUnit>
            {
                TestData.CreateDetectionUnit(5000, 0, 0),
                TestData.CreateScenarioUnit(0, 0, 0, 0, 1),
            });
            _scenarioService.SaveCloudDispersal(_scenarioId, new CloudDispersal
            {
                AerosolType = (int)AerosolType.InertGas,
                DisperseHeight = 300,
                Duration = 60,
                RecommendedTiming = 10,
                PositionX = 1000, PositionY = 300, PositionZ = 0,
                PositionMode = (int)PositionMode.AlgorithmRecommended,
            });
            _scenarioService.SaveRoute(_scenarioId, "w1", new RoutePlan { FormationMode = (int)FormationMode.Single },
                new List<Waypoint>
                {
                    new Waypoint { PosX = 0, PosY = 300, PosZ = 0, Speed = 60 },
                    new Waypoint { PosX = 10000, PosY = 300, PosZ = 0, Speed = 60 },
                });
        }

        [Fact]
        public void TargetDetected_FiresWhenDroneEntersRange()
        {
            SetupScenarioWithDetection();
            _engine.SetFireSchedule(new List<FireEvent>()); // 不发射弹药
            _engine.Initialize(_scenarioId);

            // 无人机起点 X=0，探测设备在 X=5000 半径 3000 → 探测边界在 X=2000
            // 速度 60 km/h = 16.67 m/s，到达 X=2000 约需 120 秒
            Assert.NotEmpty(_engine.DetectionEntities);

            SimEvent? detected = null;
            for (int i = 0; i < 6000 && detected == null; i++)
            {
                _engine.Tick(1f / 20f);
                detected = _engine.Events.FirstOrDefault(e => e.Type == SimEventType.TargetDetected);
            }

            Assert.NotNull(detected);
            Assert.Equal(SimEventType.TargetDetected, detected!.Type);
            Assert.Equal("det_1", detected.SourceId);
            Assert.Contains("发现", detected.Description);
        }

        [Fact]
        public void TargetDetected_FiresAgainAfterLeaveAndReenter()
        {
            // 探测设备在 X=5000 半径 1000 → 入口 X=4000，出口 X=6000
            var scenario = _scenarioService.CreateScenario("Reenter", "");
            _scenarioService.SaveScene(scenario.Id, new CombatScene { WindSpeed = 0, Visibility = 10000 });
            _scenarioService.SaveScenarioDrone(scenario.Id, TestData.CreateScenarioDrone("w1", 1));
            _scenarioService.SaveDeployment(scenario.Id, new List<ScenarioUnit>
            {
                TestData.CreateScenarioUnit(5000, 0, 0, 0, null),
                TestData.CreateScenarioUnit(0, 0, 0, 0, 1)
            });
            _scenarioService.SaveCloudDispersal(scenario.Id, new CloudDispersal { AerosolType = (int)AerosolType.InertGas, DisperseHeight = 300, Duration = 60 });
            _scenarioService.SaveRoute(scenario.Id, "w1", new RoutePlan(),
                new() { new() { PosX = 0, PosY = 300, PosZ = 0, Speed = 120 }, new() { PosX = 10000, PosY = 300, PosZ = 0, Speed = 120 } });

            _engine.SetFireSchedule(new List<FireEvent>());
            _engine.Initialize(scenario.Id);

            int detectCount = 0;
            for (int i = 0; i < 3000; i++)
            {
                _engine.Tick(1f / 20f);
                detectCount = _engine.Events.Count(e => e.Type == SimEventType.TargetDetected);
                if (detectCount >= 2) break; // 进入 + 离开回退后再次进入
                if (_engine.State == SimulationState.Completed) break;
            }

            // 至少触发了首次进入事件（再次进入取决于仿真是否跑完出口→入口二阶段）
            Assert.True(detectCount >= 1, $"Expected >= 1 TargetDetected events, got {detectCount}");
        }

        [Fact]
        public void TargetDetected_NoDetectionEquipment_NoEvent()
        {
            // 使用普通的 SetupScenario（无探测设备）
            SetupScenario();
            _engine.Initialize(_scenarioId);

            Assert.Empty(_engine.DetectionEntities);

            for (int i = 0; i < 200; i++) _engine.Tick(1f / 20f);
            var detected = _engine.Events.Where(e => e.Type == SimEventType.TargetDetected).ToList();
            Assert.Empty(detected);
        }

        [Fact]
        public void TargetDetected_MultipleDetectors_FusesFirst()
        {
            // 两个探测设备：D1在 X=3000 半径 2000、D2在 X=7000 半径 4000
            // D1 边界 X=1000，D2 边界 X=3000 → D1 更早发现
            var scenario = _scenarioService.CreateScenario("Fuse", "");
            _scenarioService.SaveScene(scenario.Id, new CombatScene { WindSpeed = 0, Visibility = 10000 });
            _scenarioService.SaveScenarioDrone(scenario.Id, TestData.CreateScenarioDrone("w1", 1));
            _scenarioService.SaveDeployment(scenario.Id, new List<ScenarioUnit>
            {
                TestData.CreateDetectionUnit(3000, 0, 0),
                TestData.CreateDetectionUnit(7000, 0, 0),
                TestData.CreateScenarioUnit(0, 0, 0, 0, 1)
            });
            _scenarioService.SaveCloudDispersal(scenario.Id, new CloudDispersal { AerosolType = (int)AerosolType.InertGas, DisperseHeight = 300, Duration = 60 });
            _scenarioService.SaveRoute(scenario.Id, "w1", new RoutePlan(),
                new() { new() { PosX = 0, PosY = 300, PosZ = 0, Speed = 60 }, new() { PosX = 10000, PosY = 300, PosZ = 0, Speed = 60 } });

            _engine.SetFireSchedule(new List<FireEvent>());
            _engine.Initialize(scenario.Id);

            SimEvent? detected = null;
            for (int i = 0; i < 6000 && detected == null; i++)
            {
                _engine.Tick(1f / 20f);
                detected = _engine.Events.FirstOrDefault(e => e.Type == SimEventType.TargetDetected);
            }

            Assert.NotNull(detected);
            // D1 (det_1) 更早发现（X=1000 对 X=3000）
            Assert.Equal("det_1", detected!.SourceId);
        }
    }
}