// Copyright Epic Games, Inc. All Rights Reserved.

using AutomationTool;
using AutomationTool.Tasks;
using EpicGames.BuildGraph;
using EpicGames.Core;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using UnrealBuildBase;

namespace AutomationTool.Tasks
{
	/// <summary>
	/// Parameters for a DotNet task
	/// </summary>
	public class DotNetTaskParameters
	{
		/// <summary>
		/// Docker command line arguments
		/// </summary>
		[TaskParameter(Optional = true)]
		public string Arguments;

		/// <summary>
		/// Base directory for running the command
		/// </summary>
		[TaskParameter(Optional = true)]
		public string BaseDir;

		/// <summary>
		/// Environment variables to set
		/// </summary>
		[TaskParameter(Optional = true)]
		public string Environment;

		/// <summary>
		/// File to read environment variables from
		/// </summary>
		[TaskParameter(Optional = true)]
		public string EnvironmentFile;

		/// <summary>
		/// The minimum exit code, which is treated as an error.
		/// </summary>
		[TaskParameter(Optional = true)]
		public int ErrorLevel = 1;

		/// <summary>
		/// Override path to dotnet executable
		/// </summary>
		[TaskParameter(Optional = true)]
		public FileReference DotNetPath;
	}

	/// <summary>
	/// Spawns Docker and waits for it to complete.
	/// </summary>
	[TaskElement("DotNet", typeof(DotNetTaskParameters))]
	public class DotNetTask : SpawnTaskBase
	{
		/// <summary>
		/// Parameters for this task
		/// </summary>
		DotNetTaskParameters Parameters;

		/// <summary>
		/// Construct a Docker task
		/// </summary>
		/// <param name="InParameters">Parameters for the task</param>
		public DotNetTask(DotNetTaskParameters InParameters)
		{
			Parameters = InParameters;
		}

		/// <summary>
		/// Execute the task.
		/// </summary>
		/// <param name="Job">Information about the current job</param>
		/// <param name="BuildProducts">Set of build products produced by this node.</param>
		/// <param name="TagNameToFileSet">Mapping from tag names to the set of files they include</param>
		public override async Task ExecuteAsync(JobContext Job, HashSet<FileReference> BuildProducts, Dictionary<string, HashSet<FileReference>> TagNameToFileSet)
		{
			FileReference DotNetFile = Parameters.DotNetPath == null ? Unreal.DotnetPath : Parameters.DotNetPath;
			if(!FileReference.Exists(DotNetFile))
			{
				throw new AutomationException("DotNet is missing from {0}", DotNetFile);
			}

			IProcessResult Result = await ExecuteAsync(DotNetFile.FullName, Parameters.Arguments, WorkingDir: Parameters.BaseDir, EnvVars: ParseEnvVars(Parameters.Environment, Parameters.EnvironmentFile));
			if (Result.ExitCode < 0 || Result.ExitCode >= Parameters.ErrorLevel)
			{
				throw new AutomationException("Docker terminated with an exit code indicating an error ({0})", Result.ExitCode);
			}
		}

		/// <summary>
		/// Output this task out to an XML writer.
		/// </summary>
		public override void Write(XmlWriter Writer)
		{
			Write(Writer, Parameters);
		}

		/// <summary>
		/// Find all the tags which are used as inputs to this task
		/// </summary>
		/// <returns>The tag names which are read by this task</returns>
		public override IEnumerable<string> FindConsumedTagNames()
		{
			yield break;
		}

		/// <summary>
		/// Find all the tags which are modified by this task
		/// </summary>
		/// <returns>The tag names which are modified by this task</returns>
		public override IEnumerable<string> FindProducedTagNames()
		{
			yield break;
		}
	}

	public static partial class StandardTasks
	{
		/// <summary>
		/// Runs a command using dotnet.
		/// </summary>
		/// <param name="Arguments">Command-line arguments.</param>
		/// <param name="BaseDir">Base directory for running the command.</param>
		/// <param name="Environment">Environment variables to set.</param>
		/// <param name="EnvironmentFile">File to read environment variables from.</param>
		/// <param name="ErrorLevel">The minimum exit code, which is treated as an error.</param>
		/// <param name="DotNetPath">Override path to dotnet executable.</param>
		public static async Task DotNetAsync(string Arguments = null, DirectoryReference BaseDir = null, string Environment = null, FileReference EnvironmentFile = null, int ErrorLevel = 1, FileReference DotNetPath = null)
		{
			DotNetTaskParameters Parameters = new DotNetTaskParameters();
			Parameters.Arguments = Arguments;
			Parameters.BaseDir = BaseDir?.FullName;
			Parameters.Environment = Environment;
			Parameters.EnvironmentFile = EnvironmentFile?.FullName;
			Parameters.ErrorLevel = ErrorLevel;
			Parameters.DotNetPath = DotNetPath;
			
			await ExecuteAsync(new DotNetTask(Parameters));
		}
	}
}