//-----------------------------------------------------------------------
// <copyright file="NuGetPack.cs" company="Andrew Arnott">
//     Copyright (c) Andrew Arnott. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------

namespace DotNetOpenAuth.BuildTasks {
	using System;
	using System.Collections.Generic;
	using System.IO;
	using System.Linq;
	using System.Text;
	using System.Xml.Linq;
	using Microsoft.Build.Framework;
	using Microsoft.Build.Utilities;

	/// <summary>
	/// Creates a .nupkg archive from a .nuspec file and content files.
	/// </summary>
	public class NuGetPack : ToolTask {
		/// <summary>
		/// Gets or sets the path to the .nuspec file.
		/// </summary>
		[Required]
		public ITaskItem NuSpec { get; set; }

		/// <summary>
		/// Gets or sets the base directory, the contents of which gets included in the .nupkg archive.
		/// </summary>
		public ITaskItem BaseDirectory { get; set; }

		/// <summary>
		/// Gets or sets the path to the directory that will contain the generated .nupkg archive.
		/// </summary>
		public ITaskItem OutputPackageDirectory { get; set; }

		/// <summary>
		/// Returns the fully qualified path to the executable file.
		/// </summary>
		/// <returns>
		/// The fully qualified path to the executable file.
		/// </returns>
		protected override string GenerateFullPathToTool() {
			return this.ToolPath;
		}

		/// <summary>
		/// Gets the name of the executable file to run.
		/// </summary>
		/// <returns>The name of the executable file to run.</returns>
		protected override string ToolName {
			get { return "NuGet.exe"; }
		}

		/// <summary>
		/// Runs the exectuable file with the specified task parameters.
		/// </summary>
		/// <returns>
		/// true if the task runs successfully; otherwise, false.
		/// </returns>
		public override bool Execute() {
			if (this.OutputPackageDirectory != null && Path.GetDirectoryName(this.OutputPackageDirectory.ItemSpec).Length > 0) {
				Directory.CreateDirectory(Path.GetDirectoryName(this.OutputPackageDirectory.ItemSpec));
			}

			string fullPackagePath = this.DeriveFullPackagePath();
			this.Log.LogMessage("Creating NuGet package '{0}'.", fullPackagePath);

			bool result = base.Execute();

			if (result) {
				this.Log.LogMessage(MessageImportance.High, "Successfully created package '{0}'.", fullPackagePath);
			}

			return result;
		}

		/// <summary>
		/// Returns a string value containing the command line arguments to pass directly to the executable file.
		/// </summary>
		/// <returns>
		/// A string value containing the command line arguments to pass directly to the executable file.
		/// </returns>
		protected override string GenerateCommandLineCommands() {
			var args = new CommandLineBuilder();

			args.AppendSwitch("pack");
			args.AppendFileNameIfNotNull(this.NuSpec);
			args.AppendSwitchIfNotNull("-b ", this.BaseDirectory);
			args.AppendSwitchIfNotNull("-o ", this.OutputPackageDirectory);

			return args.ToString();
		}

		/// <summary>
		/// Derives the path to the generated .nupkg file.
		/// </summary>
		/// <returns>A relative path.</returns>
		private string DeriveFullPackagePath() {
			var spec = XDocument.Load(this.NuSpec.ItemSpec);
			var metadata = spec.Element("package").Element("metadata");
			string id = metadata.Element("id").Value;
			string version = metadata.Element("version").Value;
			string baseDirectory = this.OutputPackageDirectory != null ? this.OutputPackageDirectory.ItemSpec : String.Empty;
			return Path.Combine(baseDirectory, String.Format("{0}.{1}.nupkg", id, version));
		}
	}
}