using System;

namespace etoy
{
    abstract class Command : IContextSetter, ICommand
    {
        bool _completed;
        bool _running;
        float _progress;
        Exception _exception;

        void IContextSetter.SetContext(Context context) => Context = context;
        bool ICommand.Start => _running;
        bool ICommand.Done => _completed;
        float ICommand.Progress => _progress;
        Exception ICommand.Exception => _exception;



        void ICommand.Execute()
        {
            if (!_running)
            {
                _running = true;

                OnProcess();
            }
        }

        /// <summary>
        /// 上下文
        /// </summary>
        protected Context Context { get; private set; }

        /// <summary>
        /// 异步完成
        /// </summary>
        protected void Completed()
        {
            _progress = 1.0f;
            _completed = true;
        }


        protected void SetException(Exception e)
        {
            _exception = e;
        }

        /// <summary>
        /// 设置进度
        /// </summary>
        /// <param name="progress"></param>
        protected void SetProgress(float progress)
        {
            if (progress >= 1.0f)
                _progress = 1.0f;
            else if (progress < 0.0f)
                _progress = 0.0f;
            else
                _progress = progress;
        }

        /// <summary>
        /// 处理回调
        /// </summary>
        protected abstract void OnProcess();

        /// <summary>
        /// 命令描述, 用于显示在控制台上
        /// </summary>
        public abstract string Description { get; }
    }
}