建立一個HotelDialogSet

首先建立出一個class叫做HotelDialogSet，然後讓這個class繼承DialogSet，透過這個方式讓邏輯整合到這個class就好。

由於之後會使用到Accessor來取得儲存的值，因此會用建構子傳入來，最後整個class：

public class HotelDialogSet : DialogSet
{
	private EchoBotAccessors _accessors;

	public HotelDialogSet(IStatePropertyAccessor<DialogState> dialogState,
		EchoBotAccessors accessors) 
		: base(dialogState)
	{
		_accessors = accessors;
	}
}

完成詢問姓名的waterfall

首先來完成詢問姓名的waterfall，整個的邏輯和之前篇幅看到的一樣，定義出一個WaterfallDialog，用來取得使用者姓名：

public class HotelDialogSet : DialogSet
{
	....
	
	public string askNameWaterfall { get; } = "askNameWaterfall";

	public HotelDialogSet
		(IStatePropertyAccessor<DialogState> dialogState, EchoBotAccessors accessors) 
		: base(dialogState)
	{
		...
		
		var askNameDialogSet = new WaterfallStep[]
		{
			StartPromptName,
			ProcessPromptName,
		};

		Add(new WaterfallDialog(askNameWaterfall, askNameDialogSet));

		Add(new TextPrompt("textPrompt"));
	}

	private async Task<DialogTurnResult> ProcessPromptName
		(WaterfallStepContext stepContext, CancellationToken cancellationToken)
	{
		var userInfo = await _accessors.UserInfo.GetAsync
			(stepContext.Context, () => new Model.UserInfo());

		userInfo.Name = stepContext.Result.ToString();

		await _accessors.UserInfo.SetAsync(stepContext.Context, userInfo);
		await _accessors.UserState.SaveChangesAsync(stepContext.Context);

		await stepContext.Context.SendActivityAsync($"{userInfo.Name} 您好");

		return await stepContext.EndDialogAsync(cancellationToken: cancellationToken);
	}

	private async Task<DialogTurnResult> StartPromptName
		(WaterfallStepContext stepContext, CancellationToken cancellationToken)
	{
		return await stepContext.PromptAsync("textPrompt", new PromptOptions()
		{
			Prompt = MessageFactory.Text("請問尊姓大名？"),
		}, 
		cancellationToken);
	}
}

上面程式碼應該不太需要介紹，定義了了一個Waterfall，裡面有兩個step用來取得姓名以及儲存在Accessor。

完成訂房的waterfall

看過了上面詢問名字的部分，相信對於訂房的做法也就很清楚了 - 一樣是建立一個waterfall，裡面定義出完成訂房需要的step。

首先是在建構子的時候建立出waterfall的step：

public HotelDialogSet
	(IStatePropertyAccessor<DialogState> dialogState, EchoBotAccessors accessors) 
	: base(dialogState)
{
	...
	
	var waterfallSteps = new WaterfallStep[]
	{
		GetStartStayDateAsync,
		GetStayDayAsync,
		GetNumberOfOccupantAsync,
		GetBedSizeAsync,
		GetConfirmAsync,
		GetSummaryAsync,
	};

	Add(new WaterfallDialog("bookRoom", waterfallSteps));
	Add(new DateTimePrompt("dateTime"));
	Add(new NumberPrompt<int>("number"));
	Add(new ChoicePrompt("choice"));
	Add(new ConfirmPrompt("confirm"));
}

再來就是看看每一個step的實際動作：

...

#region bookRoom
private async Task<DialogTurnResult> GetSummaryAsync
  (WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	if ((bool)stepContext.Result)
	{
		await stepContext.Context.SendActivityAsync
			($"訂單下定完成，訂單號：{DateTime.Now.Ticks}");
	}
	else
	{
		await stepContext.Context.SendActivityAsync("已經取消訂單");
	}

	return await stepContext.EndDialogAsync(cancellationToken: cancellationToken);
}

private async Task<DialogTurnResult> GetConfirmAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	var roomReservation = (await GetCounterState(stepContext.Context))
		.RoomReservation;

	roomReservation.BedSize = ((FoundChoice)stepContext.Result).Value;

	return await stepContext.PromptAsync("confirm", new PromptOptions()
	{
		Prompt = MessageFactory.Text($"請確認您的訂房條件：{Environment.NewLine}" +
		$"{roomReservation}")
	});
}

private async Task<DialogTurnResult> GetBedSizeAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	(await GetCounterState(stepContext.Context))
		.RoomReservation.NumberOfPepole = (int)stepContext.Result;

	var choices = new List<Choice>()
	{
		new Choice("單人床"),
		new Choice("雙人床"),
	};

	return await stepContext.PromptAsync("choice",
		new PromptOptions()
		{
			Prompt = MessageFactory.Text("請選擇床型"),
			Choices = choices,
		},
		cancellationToken);
}

private async Task<DialogTurnResult> GetNumberOfOccupantAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	(await GetCounterState(stepContext.Context))
		.RoomReservation.NumberOfNightToStay = (int)stepContext.Result - 1;

	return await stepContext.PromptAsync("number",
		new PromptOptions()
		{
			Prompt = MessageFactory.Text("幾人入住"),
		},
		cancellationToken);
}

private async Task<DialogTurnResult> GetStayDayAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	(await GetCounterState(stepContext.Context))
		.RoomReservation.StartDate =
		DateTime.Parse(((List<DateTimeResolution>)stepContext.Result).First().Value);

	return await stepContext.PromptAsync("number", new PromptOptions()
	{
		Prompt = MessageFactory.Text("請輸入要住幾天"),
	},
	cancellationToken);
}

private async Task<DialogTurnResult> GetStartStayDateAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	return await stepContext.PromptAsync("dateTime",
		new PromptOptions()
		{
			Prompt = MessageFactory.Text("請輸入入住日期"),
		},
		cancellationToken);
}
#endregion

完成root waterfall

剩下最後一個waterfall了，也就是所有的起點，root的waterfall。

一樣就是先在建構子定義出這個waterfall的step：

...
var rootSteps = new WaterfallStep[]
{
	StartRootAsync,
	ProcessRootAsync,
	LoopRootAsync,
};

Add(new WaterfallDialog("root", rootSteps));

再來看看實際step裡面執行的内容：

private async Task<DialogTurnResult> LoopRootAsync
	(WaterfallStepContext stepContext, CancellationToken cancellationToken)
{
	return await stepContext.ReplaceDialogAsync("root", null, cancellationToken);
}

private async Task<DialogTurnResult> ProcessRootAsync(WaterfallStepContext stepContext,
 CancellationToken cancellationToken)
{
	var userInfo = await _accessors.UserInfo.GetAsync(
		stepContext.Context, () => new Model.UserInfo());

	if (string.IsNullOrEmpty(userInfo.Name))
	{
		return await stepContext.BeginDialogAsync(
			askNameWaterfall, null, cancellationToken);
	}
	else if (stepContext.Result.ToString() == "訂房")
	{
		return await stepContext.BeginDialogAsync(
			"bookRoom", null, cancellationToken);
	}
	else
	{
		CounterState state = await GetCounterState(stepContext.Context);

		state.TurnCount++;

		// Set the property using the accessor.
		await _accessors.CounterState.SetAsync(stepContext.Context, state);

		// Save the new turn count into the conversation state.

		// Echo back to the user whatever they typed.
		var responseMessage = $"Name: {userInfo.Name} Turn {state.TurnCount}: You sent '{stepContext.Result}'\n";
		await stepContext.Context.SendActivityAsync(responseMessage);

		return await stepContext.ContinueDialogAsync(cancellationToken);
	}
}

private async Task<DialogTurnResult> StartRootAsync(WaterfallStepContext stepContext,
 CancellationToken cancellationToken)
{
	return await stepContext.PromptAsync("textPrompt", new PromptOptions()
	{
		Prompt = MessageFactory.Text("您好，能夠幫到您什麽？"),
	},
	cancellationToken);
}

這邊最重要的就是ProcessRootAsync以及LoopRootAsync。

在ProcessRootAsync裡面，透過呼叫BeginDialogAsync來做到branching - 依照輸入内容不同branch到不同的waterfall。

然後在LoopRootAsunc裡面呼叫ReplaceDialogAsync來做到looping。

整合到bot呼叫HotelDialogSet

最後切換到EchoWithCounterBot來設定把整個流程啓動起來。

首先把HotelDialogSet在建構子的時候建立出來：

public class EchoWithCounterBot : IBot
{
	private readonly HotelDialogSet _dialogs;
	
	public EchoWithCounterBot(EchoBotAccessors accessors,
		ILoggerFactory loggerFactory)
	{
		...

		_dialogs = new HotelDialogSet(_accessors.DialogState, accessors);
	}
}

最後要把整個啓動起來：

public async Task OnTurnAsync(ITurnContext turnContext, 
	CancellationToken cancellationToken = default(CancellationToken))
{
	if (turnContext.Activity.Type == ActivityTypes.Message)
	{
		var dc = await _dialogs.CreateContextAsync(
			turnContext, cancellationToken);

		await dc.ContinueDialogAsync(cancellationToken);

		if (!turnContext.Responded)
		{
			await dc.BeginDialogAsync
				("root", null, cancellationToken);
		}
	}
	else
	{
		await turnContext.SendActivityAsync
			($"{turnContext.Activity.Type} event detected");
	}

	await _accessors.ConversationState.SaveChangesAsync(turnContext);
}

測試結果

首先是看取得姓名的部分：

再來使用關鍵字訂房：

最後如果輸入其他任何内容，都變成echo模式：