using System;
using NUnit.Framework;
using TrueCraft.Core.TerrainGen;
using TrueCraft.API;
using TrueCraft.Core.AI;
using TrueCraft.API.World;
using TrueCraft.Core.World;
using System.Linq;

namespace TrueCraft.Core.Test.AI
{
    [TestFixture]
    public class PathFindingTest
    {
        private void DrawGrid(PathResult path, IWorld world)
        {
            for (int z = -8; z < 8; z++)
            {
                for (int x = -8; x < 8; x++)
                {
                    var coords = new Coordinates3D(x, 4, z);
                    if (path.Waypoints.Contains(coords))
                        Console.Write("o");
                    else
                    {
                        var id = world.GetBlockID(coords);
                        if (id != 0)
                            Console.Write("x");
                        else
                            Console.Write("_");
                    }
                }
                Console.WriteLine();
            }
        }

        [Test]
        public void TestAStarLinearPath()
        {
            var world = new TrueCraft.Core.World.World("default", new FlatlandGenerator());
            var astar = new AStarPathFinder();
            var path = astar.FindPath(world, new BoundingBox(),
               new Coordinates3D(0, 4, 0), new Coordinates3D(5, 4, 0));
            DrawGrid(path, world);
            var expected = new[]
            {
                new Coordinates3D(0, 4, 0),
                new Coordinates3D(1, 4, 0),
                new Coordinates3D(2, 4, 0),
                new Coordinates3D(3, 4, 0),
                new Coordinates3D(4, 4, 0),
                new Coordinates3D(5, 4, 0)
            };
            for (int i = 0; i < path.Waypoints.Count; i++)
                Assert.AreEqual(expected[i], path.Waypoints[i]);
        }

        [Test]
        public void TestAStarDiagonalPath()
        {
            var world = new TrueCraft.Core.World.World("default", new FlatlandGenerator());
            var astar = new AStarPathFinder();
            var start = new Coordinates3D(0, 4, 0);
            var end = new Coordinates3D(5, 4, 5);
            var path = astar.FindPath(world, new BoundingBox(), start, end);
            DrawGrid(path, world);
            // Just test the start and end, the exact results need to be eyeballed
            Assert.AreEqual(start, path.Waypoints[0]);
            Assert.AreEqual(end, path.Waypoints[path.Waypoints.Count - 1]);
        }

        [Test]
        public void TestAStarObstacle()
        {
            var world = new TrueCraft.Core.World.World("default", new FlatlandGenerator());
            var astar = new AStarPathFinder();
            var start = new Coordinates3D(0, 4, 0);
            var end = new Coordinates3D(5, 4, 0);
            world.SetBlockID(new Coordinates3D(3, 4, 0), 1); // Obstacle
            var path = astar.FindPath(world, new BoundingBox(), start, end);
            DrawGrid(path, world);
            // Just test the start and end, the exact results need to be eyeballed
            Assert.AreEqual(start, path.Waypoints[0]);
            Assert.AreEqual(end, path.Waypoints[path.Waypoints.Count - 1]);
            Assert.IsFalse(path.Waypoints.Contains(new Coordinates3D(3, 4, 0)));
        }

        [Test]
        public void TestAStarImpossible()
        {
            var world = new TrueCraft.Core.World.World("default", new FlatlandGenerator());
            var astar = new AStarPathFinder();
            var start = new Coordinates3D(0, 4, 0);
            var end = new Coordinates3D(5, 4, 0);

            world.SetBlockID(start + Coordinates3D.East, 1);
            world.SetBlockID(start + Coordinates3D.West, 1);
            world.SetBlockID(start + Coordinates3D.North, 1);
            world.SetBlockID(start + Coordinates3D.South, 1);

            var path = astar.FindPath(world, new BoundingBox(), start, end);
            Assert.IsNull(path);
        }
    }
}