using System;
using MinecraftClient.Mapping;
using MinecraftClient.Pathing.Core;
using MinecraftClient.Pathing.Execution;
using MinecraftClient.Pathing.Execution.Templates;
using MinecraftClient.Physics;
using Xunit;

namespace MinecraftClient.Tests.Pathing.Execution;

public sealed class GroundedTemplateConvergenceTests
{
    [Fact]
    public void WalkTemplate_FinalStop_Completes_WhenFootprintStaysInsideTargetBlock()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor();
        var segment = new PathSegment
        {
            Start = new Location(0.5, 80, 0.5),
            End = new Location(1.5, 80, 0.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.FinalStop
        };

        var template = new WalkTemplate(segment, null);
        var physics = TemplateSimulationRunner.CreateGroundedPhysics(segment.Start, yaw: 270f);

        TemplateState state = TemplateSimulationRunner.Run(template, physics, world, maxTicks: 160, out Location finalPos);

        Assert.True(state == TemplateState.Complete, $"state={state} finalPos={finalPos} vel={physics.DeltaMovement}");
        Assert.True(TemplateFootingHelper.IsFootprintInsideTargetBlock(finalPos, segment.End));
    }

    [Fact]
    public void WalkTemplate_FinalStop_Completes_WhenCenterStopsInsideTargetBlockNearEdge()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor();
        var segment = new PathSegment
        {
            Start = new Location(2.5, 80, 0.5),
            End = new Location(3.5, 80, 0.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.FinalStop
        };

        var template = new WalkTemplate(segment, null);
        var physics = new PlayerPhysics
        {
            Position = new Vec3d(3.2897, 80.0, 0.5),
            DeltaMovement = Vec3d.Zero,
            OnGround = true,
            MovementSpeed = 0.1f,
            Yaw = 270f
        };

        var input = new MovementInput();
        TemplateState state = template.Tick(new Location(physics.Position.X, physics.Position.Y, physics.Position.Z), physics, input, world);

        Assert.Equal(TemplateState.Complete, state);
    }

    [Fact]
    public void WalkTemplate_FinalStop_Completes_FromLiveNearGoalState_WithoutFailure()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor(min: 95, max: 115);
        var segment = new PathSegment
        {
            Start = new Location(102.5, 80, 100.5),
            End = new Location(103.5, 80, 100.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.FinalStop
        };

        var template = new WalkTemplate(segment, null);
        var physics = new PlayerPhysics
        {
            Position = new Vec3d(103.36, 80.0, 100.50),
            DeltaMovement = new Vec3d(0.0346, 0.0, 0.0),
            OnGround = true,
            MovementSpeed = 0.1f,
            Yaw = 270f
        };

        TemplateState state = TemplateSimulationRunner.Run(template, physics, world, maxTicks: 40, out _);

        Assert.Equal(TemplateState.Complete, state);
    }

    [Fact]
    public void WalkTemplate_PrepareJump_CompletesWithoutSettlingOnRunUpBlock()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor();
        var current = new PathSegment
        {
            Start = new Location(0.5, 80, 0.5),
            End = new Location(1.5, 80, 0.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.PrepareJump,
            PreserveSprint = true
        };
        var next = new PathSegment
        {
            Start = new Location(1.5, 80, 0.5),
            End = new Location(3.5, 80, 0.5),
            MoveType = MoveType.Parkour,
            ExitTransition = PathTransitionType.FinalStop
        };

        var template = new WalkTemplate(current, next);
        var physics = TemplateSimulationRunner.CreateGroundedPhysics(current.Start, yaw: 270f);

        TemplateState state = TemplateSimulationRunner.Run(template, physics, world, maxTicks: 60, out _);

        Assert.Equal(TemplateState.Complete, state);
        Assert.True(physics.DeltaMovement.X > 0.02);
    }

    [Fact]
    public void WalkTemplate_TurnIntoParkour_CompletesOnlyWhenTurnEntryIsSlowAndJumpReady()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor(min: 108, max: 128);

        var current = new PathSegment
        {
            Start = new Location(120.5, 80, 110.5),
            End = new Location(121.5, 80, 110.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.Turn,
            ExitHints = new PathTransitionHints(0, 1, 0.08, 0.16, false, true, true, true, 12)
        };
        var next = new PathSegment
        {
            Start = new Location(121.5, 80, 110.5),
            End = new Location(121.5, 80, 111.5),
            MoveType = MoveType.Traverse,
            ExitTransition = PathTransitionType.PrepareJump,
            ExitHints = new PathTransitionHints(0, 1, 0.12, double.PositiveInfinity, false, true, true, false, 10),
            PreserveSprint = true
        };

        var template = new WalkTemplate(current, next);
        var physics = TemplateSimulationRunner.CreateGroundedPhysics(current.Start, yaw: 270f);

        TemplateState state = TemplateSimulationRunner.Run(template, physics, world, maxTicks: 140, out Location finalPos);
        double horizontalSpeed = Math.Sqrt(physics.DeltaMovement.X * physics.DeltaMovement.X + physics.DeltaMovement.Z * physics.DeltaMovement.Z);

        Assert.Equal(TemplateState.Complete, state);
        Assert.True(
            TemplateFootingHelper.IsCenterInsideSupportStrip(finalPos, current.End, next.End),
            $"finalPos={finalPos} vel={physics.DeltaMovement}");
        Assert.InRange(horizontalSpeed, 0.08, 0.20);
    }

    [Fact]
    public void DescendTemplate_LandingRecovery_CompletesOnLandingBlock()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor();
        FlatWorldTestBuilder.ClearBox(world, 1, 79, 0, 1, 79, 0);
        FlatWorldTestBuilder.SetSolid(world, 1, 78, 0);

        var segment = new PathSegment
        {
            Start = new Location(0.5, 80, 0.5),
            End = new Location(1.5, 79, 0.5),
            MoveType = MoveType.Descend,
            ExitTransition = PathTransitionType.LandingRecovery
        };

        var template = new DescendTemplate(segment, null);
        var physics = TemplateSimulationRunner.CreateGroundedPhysics(segment.Start, yaw: 270f);

        TemplateState state = TemplateSimulationRunner.Run(template, physics, world, maxTicks: 240, out Location finalPos);

        Assert.True(state == TemplateState.Complete, $"state={state} finalPos={finalPos} vel={physics.DeltaMovement}");
        Assert.True(TemplateFootingHelper.IsFootprintInsideTargetBlock(finalPos, segment.End));
    }

    [Fact]
    public void DescendTemplate_FinalStop_WithWallAndMisalignedYaw_CompletesOnLandingBlock()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor(min: 198, max: 204);
        FlatWorldTestBuilder.ClearBox(world, 198, 79, 198, 204, 84, 202);
        FlatWorldTestBuilder.FillSolid(world, 201, 79, 199, 203, 79, 201);
        FlatWorldTestBuilder.SetSolid(world, 200, 80, 200);
        FlatWorldTestBuilder.SetSolid(world, 200, 80, 199);
        FlatWorldTestBuilder.SetSolid(world, 201, 80, 199);
        FlatWorldTestBuilder.SetSolid(world, 202, 80, 199);
        FlatWorldTestBuilder.SetSolid(world, 201, 81, 199);
        FlatWorldTestBuilder.SetSolid(world, 202, 81, 199);

        var segment = new PathSegment
        {
            Start = new Location(200.5, 81, 200.5),
            End = new Location(201.5, 80, 200.5),
            MoveType = MoveType.Descend,
            ExitTransition = PathTransitionType.FinalStop
        };

        var template = new DescendTemplate(segment, null);
        var physics = TemplateSimulationRunner.CreateGroundedPhysics(segment.Start, yaw: 0f);

        var input = new MovementInput();
        var trace = new List<string>();
        TemplateState state = TemplateState.InProgress;
        Location finalPos = segment.Start;
        for (int tick = 0; tick < 240; tick++)
        {
            input.Reset();
            Location pos = new(physics.Position.X, physics.Position.Y, physics.Position.Z);
            state = template.Tick(pos, physics, input, world);
            if (tick < 20 || state != TemplateState.InProgress || !physics.OnGround)
            {
                trace.Add($"tick={tick} state={state} pos={pos} vel={physics.DeltaMovement} onGround={physics.OnGround} input(F={input.Forward},B={input.Back},S={input.Sprint})");
            }

            if (state != TemplateState.InProgress)
            {
                finalPos = new Location(physics.Position.X, physics.Position.Y, physics.Position.Z);
                break;
            }

            physics.ApplyInput(input);
            physics.Tick(world);
            finalPos = new Location(physics.Position.X, physics.Position.Y, physics.Position.Z);
        }

        Assert.True(state == TemplateState.Complete, $"state={state} finalPos={finalPos} vel={physics.DeltaMovement}\n{string.Join('\n', trace)}");
        Assert.True(TemplateFootingHelper.IsFootprintInsideTargetBlock(finalPos, segment.End));
    }

    [Fact]
    public void DescendTemplate_AppliesAirBrake_WhenPlannerRequiresBrake()
    {
        World world = FlatWorldTestBuilder.CreateStoneFloor(min: -2, max: 4);
        FlatWorldTestBuilder.ClearBox(world, -2, 79, -2, 4, 84, 2);
        FlatWorldTestBuilder.SetSolid(world, 1, 79, 0);

        var segment = new PathSegment
        {
            Start = new Location(0.5, 81, 0.5),
            End = new Location(1.5, 80, 0.5),
            MoveType = MoveType.Descend,
            ExitTransition = PathTransitionType.LandingRecovery,
            ExitHints = new PathTransitionHints(1, 0, 0.0, 0.0, true, true, false, true, 12)
        };

        var template = new DescendTemplate(segment, null);
        var physics = new PlayerPhysics
        {
            Position = new Vec3d(1.38, 80.56, 0.5),
            DeltaMovement = new Vec3d(0.42, -0.22, 0.0),
            OnGround = false,
            MovementSpeed = 0.1f,
            Yaw = 270f
        };

        Location pos = new(physics.Position.X, physics.Position.Y, physics.Position.Z);
        TransitionBrakingDecision decision = TransitionBrakingPlanner.Plan(segment, null, pos, physics, world);
        var input = new MovementInput();
        template.Tick(pos, physics, input, world);

        Assert.Equal(TransitionBrakingDecision.Brake, decision);
        Assert.True(input.Back, $"decision={decision} input(F={input.Forward},B={input.Back},S={input.Sprint})");
        Assert.False(input.Forward, $"decision={decision} input(F={input.Forward},B={input.Back},S={input.Sprint})");
    }
}