namespace Digger
{
    public class Terrain : ICreature
    {
        public CreatureCommand Act(int x, int y) => new CreatureCommand {DeltaX = 0, DeltaY = 0};

        public bool DeadInConflict(ICreature conflictedObject) => true;

        public int GetDrawingPriority() => 2;

        public string GetImageFileName() => "Terrain.png";
    }

    public class Player : ICreature
    {
        public CreatureCommand Act(int x, int y)
        {
            switch (Game.KeyPressed)
            {
                case System.Windows.Forms.Keys.Left:
                    if (IsStepPossible(x - 1, y))
                        return new CreatureCommand {DeltaX = -1, DeltaY = 0};
                    break;

                case System.Windows.Forms.Keys.Up:
                    if (IsStepPossible(x, y - 1))
                        return new CreatureCommand {DeltaX = 0, DeltaY = -1};
                    break;

                case System.Windows.Forms.Keys.Right:
                    if (IsStepPossible(x + 1, y))
                        return new CreatureCommand {DeltaX = 1, DeltaY = 0};
                    break;

                case System.Windows.Forms.Keys.Down:
                    if (IsStepPossible(x, y + 1))
                        return new CreatureCommand {DeltaX = 0, DeltaY = 1};
                    break;
            }

            return new CreatureCommand();
        }

        public bool DeadInConflict(ICreature conflictedObject)
        {
            if (conflictedObject is Gold)
            {
                Game.Scores += 10;
                return false;
            }

            return conflictedObject is Sack;
        }

        public int GetDrawingPriority() => 1;

        public string GetImageFileName() => "Digger.png";

        private bool IsStepPossible(int x, int y)
        {
            if (!(x >= 0 && x < Game.MapWidth && y >= 0 && y < Game.MapHeight))
                return false;

            return Game.Map[x, y] == null || !(Game.Map[x, y] is Sack);
        }
    }

    public class Sack : ICreature
    {
        private int counter;

        public CreatureCommand Act(int x, int y)
        {
            if (y < Game.MapHeight - 1)
            {
                var map = Game.Map[x, y + 1];

                if (map == null || counter > 0 && map is Player)
                {
                    counter++;
                    return new CreatureCommand {DeltaX = 0, DeltaY = 1};
                }
            }

            if (counter > 1)
                return new CreatureCommand {DeltaX = 0, DeltaY = 0, TransformTo = new Gold()};

            counter = 0;
            return new CreatureCommand {DeltaX = 0, DeltaY = 0};
        }

        public bool DeadInConflict(ICreature conflictedObject) => false;

        public int GetDrawingPriority() => 5;

        public string GetImageFileName() => "Sack.png";
    }

    public class Gold : ICreature
    {
        public CreatureCommand Act(int x, int y) => new CreatureCommand {DeltaX = 0, DeltaY = 0};

        public bool DeadInConflict(ICreature conflictedObject) => conflictedObject is Player;

        public int GetDrawingPriority() => 3;

        public string GetImageFileName() => "Gold.png";
    }
}