using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Downloader
{
	/// <summary>
	/// 下载任务管理器
	/// </summary>
	class DownTaskManager
	{
		private Dictionary<string, DownTask> DownTasks = new Dictionary<string, DownTask>();

		/// <summary>
		/// 创建下载任务
		/// </summary>
		/// <returns>任务</returns>
		public DownTask MakeDownTask(string URL, string path, int threadNum)
		{
			// 简单工厂策略
			return new DownTask(URL, path, threadNum);
		}

		/// <summary>
		/// 添加到任务队列
		/// </summary>
		/// <param name="name">任务名</param>
		/// <param name="downTask">任务对象</param>
		/// <returns>成功与否，false表示任务名已存在</returns>
		public bool Add(string name, DownTask downTask)
		{
			if (this.DownTasks.ContainsKey(name))
			{
				// 存在则返回false
				return false;
			}
			else
			{
				// 不存在则添加后放回true
				this.DownTasks.Add(name, downTask);
				return true;
			}
		}

		/// <summary>
		/// 通过任务名开始任务
		/// </summary>
		/// <param name="taskName">任务名</param>
		/// <returns>成功与否，false代表不存在此任务</returns>
		public bool StartsByName(string taskName)
		{
			if (this.DownTasks.ContainsKey(taskName))
			{
				// 存在则返回false
				return false;
			}
			else
			{
				// 不存在则做事后放回true
				this.DownTasks[taskName].StartAsync();
				return true;
			}
		}

		/// <summary>
		/// 通过任务名暂停任务
		/// </summary>
		/// <param name="taskName">任务名</param>
		/// <returns>成功与否，false代表不存在此任务</returns>
		public bool PauseByName(string taskName)
		{
			if (this.DownTasks.ContainsKey(taskName))
			{
				// 存在则返回false
				return false;
			}
			else
			{
				// 不存在则做事后放回true
				this.DownTasks[taskName].Pause();
				return true;
			}
		}

		/// <summary>
		/// 通过任务名停止任务
		/// </summary>
		/// <param name="taskName">任务名</param>
		/// <returns>成功与否，false代表不存在此任务</returns>
		public bool StopByName(string taskName)
		{
			if (this.DownTasks.ContainsKey(taskName))
			{
				// 存在则返回false
				return false;
			}
			else
			{
				// 不存在则做事后放回true
				this.DownTasks[taskName].Stop();
				return true;
			}
		}

		/// <summary>
		/// 开始所有任务
		/// </summary>
		public void StartAll()
		{
			foreach (var item in this.DownTasks.Values)
			{
				item.StartAsync();
			}
		}

		/// <summary>
		/// 暂停所有任务
		/// </summary>
		public void PauseAll()
		{
			foreach (var item in this.DownTasks.Values)
			{
				item.Pause();
			}
		}

		/// <summary>
		/// 停止所有任务
		/// </summary>
		public void StopAll()
		{
			foreach (var item in this.DownTasks.Values)
			{
				item.Stop();
			}
		}

		/// <summary>
		/// 获取所有任务的信息
		/// </summary>
		/// <returns>任务信息数组</returns>
		public string[] GetAllTaskNews()
		{
			string[] names = new string[this.DownTasks.Count];
			for (int i = 0; i < this.DownTasks.Count; i++)
			{
				string key = this.DownTasks.ElementAt(i).Key;
				names[i] = $"{i} - {key}，下载速度：{this.DownTasks[key].Speed}\\s，下载进度：{this.DownTasks[key].Progress}%";
			}
			return names;
		}
	}
}