using System.Collections.Generic;
using CounterDrone.Core.Algorithms;
using CounterDrone.Core.Models;
using CounterDrone.Core.Simulation;
using Xunit;

namespace CounterDrone.Core.Tests
{
    public class DroneEntityTests
    {
        private TargetConfig CreateConfig(float speed = 120, float altitude = 300)
        {
            return new TargetConfig
            {
                TargetType = (int)TargetType.Piston,
                PowerType = (int)PowerType.Piston,
                TypicalSpeed = speed,
                TypicalAltitude = altitude,
                Wingspan = 2.5,
                Quantity = 1,
            };
        }

        private List<Waypoint> CreateRoute(float fromX, float toX, float alt, float speed)
        {
            return new List<Waypoint>
            {
                new() { PosX = fromX, PosY = alt, PosZ = 0, Altitude = alt, Speed = speed },
                new() { PosX = toX, PosY = alt, PosZ = 0, Altitude = alt, Speed = speed },
            };
        }

        [Fact]
        public void InitialPosition_IsFirstWaypoint()
        {
            var drone = new DroneEntity("d1", "g1", CreateConfig(),
                CreateRoute(100, 500, 300, 120), 0, 50, 0, 0, FormationMode.Single);
            Assert.Equal(100, drone.PosX, 1);
            Assert.Equal(300, drone.PosY, 1);
        }

        [Fact]
        public void Update_MovesTowardTarget()
        {
            var drone = new DroneEntity("d1", "g1", CreateConfig(),
                CreateRoute(0, 1000, 300, 120), 0, 50, 0, 0, FormationMode.Single);
            float prevX = drone.PosX;
            drone.Update(1f);
            Assert.True(drone.PosX > prevX);
        }

        [Fact]
        public void Update_ReachesTarget_StatusChanges()
        {
            var drone = new DroneEntity("d1", "g1", CreateConfig(360),
                CreateRoute(0, 100, 300, 360), 0, 50, 0, 0, FormationMode.Single);
            drone.Update(2f);
            Assert.Equal(DroneStatus.ReachedTarget, drone.Status);
        }

        [Fact]
        public void Damage_ReducesHp()
        {
            var drone = new DroneEntity("d1", "g1", CreateConfig(),
                CreateRoute(0, 100, 300, 60), 0, 50, 0, 0, FormationMode.Single);
            drone.ApplyDamage(0.4f);
            Assert.Equal(0.6f, drone.Hp, 0.01f);
        }

        [Fact]
        public void Damage_ExceedingHp_Destroys()
        {
            var drone = new DroneEntity("d1", "g1", CreateConfig(),
                CreateRoute(0, 100, 300, 60), 0, 50, 0, 0, FormationMode.Single);
            drone.ApplyDamage(1.5f);
            Assert.True(drone.Hp <= 0);
            Assert.Equal(DroneStatus.Destroyed, drone.Status);
        }

        [Fact]
        public void Formation_Lateral_ZOffsetsDiffer()
        {
            var route = CreateRoute(0, 100, 300, 60);
            var d0 = new DroneEntity("d0", "g1", CreateConfig(), route, 0, 50, 0, 0, FormationMode.Formation);
            var d1 = new DroneEntity("d1", "g1", CreateConfig(), route, 1, 50, 0, 0, FormationMode.Formation);
            var d2 = new DroneEntity("d2", "g1", CreateConfig(), route, 2, 50, 0, 0, FormationMode.Formation);
            // 起始Z不同
            Assert.NotEqual(d0.PosZ, d1.PosZ);
            Assert.NotEqual(d1.PosZ, d2.PosZ);
            // 航点Z不同（偏移持久化到航点）
            Assert.NotEqual(d0.Route[0].PosZ, d1.Route[0].PosZ);
            Assert.NotEqual(d0.Route[1].PosZ, d1.Route[1].PosZ);
        }

        [Fact]
        public void Formation_Longitudinal_XOffsetsDiffer()
        {
            var route = CreateRoute(0, 100, 300, 60);
            var d0 = new DroneEntity("d0", "g1", CreateConfig(), route, 0, 0, 0, 100, FormationMode.Formation);
            var d1 = new DroneEntity("d1", "g1", CreateConfig(), route, 0, 0, 1, 100, FormationMode.Formation);
            Assert.NotEqual(d0.PosX, d1.PosX);
        }

        [Fact]
        public void Formation_Mixed_2x2()
        {
            var route = CreateRoute(0, 100, 300, 60);
            var d0 = new DroneEntity("d0", "g1", CreateConfig(), route, 0, 50, 0, 100, FormationMode.Formation);
            var d1 = new DroneEntity("d1", "g1", CreateConfig(), route, 1, 50, 0, 100, FormationMode.Formation);
            var d2 = new DroneEntity("d2", "g1", CreateConfig(), route, 0, 50, 1, 100, FormationMode.Formation);
            var d3 = new DroneEntity("d3", "g1", CreateConfig(), route, 1, 50, 1, 100, FormationMode.Formation);
            Assert.NotEqual(d0.PosZ, d1.PosZ); // lateral
            Assert.NotEqual(d0.PosX, d2.PosX); // longitudinal
        }

        [Fact]
        public void Swarm_ProducesRandomOffsets()
        {
            var route = CreateRoute(0, 100, 300, 60);
            var d0 = new DroneEntity("d0", "g1", CreateConfig(), route, 0, 30, 0, 0, FormationMode.Swarm);
            var d1 = new DroneEntity("d1", "g1", CreateConfig(), route, 1, 30, 0, 0, FormationMode.Swarm);
            Assert.True(d0.PosX != d1.PosX || d0.PosZ != d1.PosZ);
        }

        // ═══════════════════════════════════════
        // RouteGeometry 驱动的多 waypoint 折线运动
        //   验证无人机沿 L 形航路（X 段→Z 段）正确移动并最终到达终点
        // ═══════════════════════════════════════

        [Fact]
        public void MultiWaypoint_LShape_MovesAlongBothSegments()
        {
            // L 形航路：(0,0) → (100,0) → (100,100)，总长 200m，速度 60km/h≈16.67m/s
            var route = new List<Waypoint>
            {
                new() { PosX = 0,   PosY = 300, PosZ = 0,   Altitude = 300, Speed = 60 },
                new() { PosX = 100, PosY = 300, PosZ = 0,   Altitude = 300, Speed = 60 },
                new() { PosX = 100, PosY = 300, PosZ = 100, Altitude = 300, Speed = 60 },
            };
            var drone = new DroneEntity("d1", "g1", CreateConfig(speed: 60), route,
                0, 0, 0, 0, FormationMode.Single);

            // 推进到第一段中点（弧长 50）：应在 X=50, Z=0
            drone.Update(50f / (60f / 3.6f));
            Assert.Equal(50f, drone.PosX, 1);
            Assert.Equal(0f, drone.PosZ, 1);
            Assert.Equal(DroneStatus.Flying, drone.Status);

            // 推进到拐点（弧长 100）：应在 X=100, Z=0
            drone.Update(50f / (60f / 3.6f));
            Assert.Equal(100f, drone.PosX, 1);
            Assert.Equal(0f, drone.PosZ, 1);
            Assert.Equal(DroneStatus.Flying, drone.Status);

            // 推进到第二段中点（弧长 150）：应在 X=100, Z=50
            drone.Update(50f / (60f / 3.6f));
            Assert.Equal(100f, drone.PosX, 1);
            Assert.Equal(50f, drone.PosZ, 1);
            Assert.Equal(DroneStatus.Flying, drone.Status);

            // 推进到终点（弧长 200）：应在 X=100, Z=100，状态 ReachedTarget
            drone.Update(50f / (60f / 3.6f));
            Assert.Equal(100f, drone.PosX, 1);
            Assert.Equal(100f, drone.PosZ, 1);
            Assert.Equal(DroneStatus.ReachedTarget, drone.Status);
        }

        // ═══════════════════════════════════════
        // 弧长缓存一致性：多段航路上非整段边界处的位置必须与 RouteGeometry.PositionAt 精确一致
        //   防止 Update() 内段长缓存引入的数值偏差
        // ═══════════════════════════════════════

        [Fact]
        public void MultiWaypoint_SubSegmentPositions_MatchGeometry()
        {
            // 不规则三段折线，段长各异（50, 120, 80），避免整段边界凑巧对齐
            var route = new List<Waypoint>
            {
                new() { PosX = 0,   PosY = 300, PosZ = 0,   Altitude = 300, Speed = 60 },
                new() { PosX = 50,  PosY = 300, PosZ = 0,   Altitude = 300, Speed = 60 },  // 段1: 50m
                new() { PosX = 50,  PosY = 300, PosZ = 120, Altitude = 300, Speed = 60 },  // 段2: 120m
                new() { PosX = 130, PosY = 300, PosZ = 120, Altitude = 300, Speed = 60 },  // 段3: 80m
            };
            const float speed = 60f;
            float speedMs = speed / 3.6f;

            // 取若干非整段边界的弧长采样点，验证每一步位置 = RouteGeometry.PositionAt
            float[] sampleArcs = { 17f, 50f, 73f, 170f, 200f, 249f };
            foreach (var arc in sampleArcs)
            {
                var drone = new DroneEntity("d", "g", CreateConfig(speed), route,
                    0, 0, 0, 0, FormationMode.Single);
                drone.Update(arc / speedMs);
                var (ex, ey, ez) = RouteGeometry.PositionAt(route, arc);
                Assert.True(System.Math.Abs(drone.PosX - ex) < 0.5f, $"arc={arc}: X {drone.PosX} vs {ex}");
                Assert.True(System.Math.Abs(drone.PosY - ey) < 0.5f, $"arc={arc}: Y {drone.PosY} vs {ey}");
                Assert.True(System.Math.Abs(drone.PosZ - ez) < 0.5f, $"arc={arc}: Z {drone.PosZ} vs {ez}");
            }
        }
    }
}