// Licensed to the .NET Foundation under one or more agreements.

// The .NET Foundation licenses this file to you under the MIT license.

// See the LICENSE file in the project root for more information.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

namespace Cake.Core

{

/// <summary>

/// A <see cref="CakeTask"/> represents a unit of work.

/// </summary>

public sealed class CakeTask : ICakeTaskInfo

{

/// <inheritdoc/>

public string Name { get; }

/// <inheritdoc/>

public string Description { get; set; }

/// <summary>

/// Gets the task's dependencies.

/// </summary>

/// <value>The task's dependencies.</value>

public List<CakeTaskDependency> Dependencies { get; }

/// <summary>

/// Gets the tasks that the task want to be a dependency of.

/// </summary>

/// <value>The tasks that the task want to be a dependency of.</value>

public List<CakeTaskDependency> Dependees { get; }

/// <summary>

/// Gets the task's criterias.

/// </summary>

/// <value>The task's criterias.</value>

public List<CakeTaskCriteria> Criterias { get; }

/// <summary>

/// Gets or sets the error handler.

/// </summary>

/// <value>The error handler.</value>

public Func<Exception, ICakeContext, Task> ErrorHandler { get; set; }

/// <summary>

/// Gets or sets the error reporter.

/// </summary>

public Func<Exception, Task> ErrorReporter { get; set; }

/// <summary>

/// Gets or sets the finally handler.

/// </summary>

public Func<ICakeContext, Task> FinallyHandler { get; set; }

/// <summary>

/// Gets the task's actions.

/// </summary>

/// <value>The task's actions.</value>

public List<Func<ICakeContext, Task>> Actions { get; }

/// <summary>

/// Gets the task's actions that are run at execution time to additionally populate <see cref="Actions"/>.

/// </summary>

/// <value>The task's delayed actions actions.</value>

public Queue<Action<ICakeContext>> DelayedActions { get; }

/// <summary>

/// Gets or sets a value indicating whether gets the task's state if it will defer exceptions until the end of the task.

/// </summary>

/// <value>The task's defer exceptions state.</value>

public bool DeferExceptions { get; set; }

IReadOnlyList<CakeTaskDependency> ICakeTaskInfo.Dependencies => Dependencies;

IReadOnlyList<CakeTaskDependency> ICakeTaskInfo.Dependees => Dependees;

/// <summary>

/// Initializes a new instance of the <see cref="CakeTask"/> class.

/// </summary>

/// <param name="name">The name of the task.</param>

public CakeTask(string name)

{

ArgumentNullException.ThrowIfNull(name);

if (string.IsNullOrWhiteSpace(name))

{

throw new ArgumentException("Task name cannot be empty.");

}

Name = name;

Dependencies = new List<CakeTaskDependency>();

Dependees = new List<CakeTaskDependency>();

Criterias = new List<CakeTaskCriteria>();

Actions = new List<Func<ICakeContext, Task>>();

DelayedActions = new Queue<Action<ICakeContext>>();

}

/// <summary>

/// Executes the task using the specified context.

/// </summary>

/// <param name="context">The context.</param>

/// <returns>Returned Task.</returns>

public async Task Execute(ICakeContext context)

{

while (DelayedActions.Count > 0)

{

var delayedDelegate = DelayedActions.Dequeue();

delayedDelegate(context);

}

var exceptions = new List<Exception>();

foreach (var action in Actions)

{

try

{

await action(context).ConfigureAwait(false);

}

catch (Exception e) when (DeferExceptions)

{

exceptions.Add(e);

}

}

if (exceptions.Any())

{

if (exceptions.Count == 1)

{

throw exceptions.Single();

}

throw new AggregateException("Task failed with following exceptions", exceptions);

}

}

}

}