FileTime/src/Core/FileTime.Core/Timeline/ParallelCommands.cs

using FileTime.Core.Command;

namespace FileTime.Core.Timeline
{
    public class ParallelCommands
    {
        private static ushort _idCounter;
        public List<CommandTimeState> _commands;
        public ushort Id { get; }
        public IReadOnlyList<CommandTimeState> Commands { get; }
        public PointInTime? Result { get; private set; }

        public ParallelCommands(PointInTime? result)
            : this(new List<CommandTimeState>(), result) { }

        private ParallelCommands(List<CommandTimeState> commands, PointInTime? result)
        {
            Id = _idCounter++;

            _commands = commands;
            Commands = _commands.AsReadOnly();

            Result = result;
        }

        public static async Task<ParallelCommands> Create(PointInTime? startTime, IEnumerable<ICommand> commands)
        {
            var commandStates = new List<CommandTimeState>();
            var currentTime = startTime;
            foreach (var command in commands)
            {
                CommandTimeState commandTimeState = new(command, currentTime);
                if (currentTime != null)
                {
                    var canRun = await command.CanRun(currentTime);
                    if (canRun == CanCommandRun.True)
                    {
                        currentTime = await command.SimulateCommand(currentTime);
                    }
                    else
                    {
                        currentTime = null;
                    }
                }

                commandStates.Add(commandTimeState);
            }

            return new ParallelCommands(commandStates, currentTime);
        }

        public async Task AddCommand(ICommand command)
        {
            _commands.Add(new CommandTimeState(command, Result));
            if (Result != null)
            {
                Result = await command.SimulateCommand(Result);
            }
        }

        public async Task<PointInTime?> RefreshResult(PointInTime? startPoint)
        {
            var result = startPoint;
            foreach (var command in _commands)
            {
                await command.UpdateState(result);
                if (result != null)
                {
                    var canRun = await command.Command.CanRun(result);
                    if (canRun == CanCommandRun.True || (canRun == CanCommandRun.Forceable && command.ForceRun))
                    {
                        result = await command.Command.SimulateCommand(result);
                    }
                    else
                    {
                        result = null;
                    }
                }
            }

            Result = result;
            return Result;
        }

        public void RemoveAt(int number) => _commands.RemoveAt(number);

        internal void Remove(CommandTimeState command) => _commands.Remove(command);
    }
}