using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Runtime.InteropServices;

using Microsoft.Build.Framework;
using Microsoft.Build.BuildEngine;
using Microsoft.Build.Utilities;

namespace Elsinore.Engine.MSBuild.Web
{
	public class BuildHandler : IHttpHandler
	{
		public const string BuildFileKey = "BuildFile";
		public const string TargetParam = "__Target";

		public bool IsReusable
		{
			get { return true; }
		}

		public void ProcessRequest(HttpContext context)
		{
			context.Response.ContentType = "text/plain";

			string[] targets = null;
			BuildPropertyGroup buildPropertyGroup = new BuildPropertyGroup();

			foreach (string key in context.Request.Params.AllKeys)
			{
				string value = context.Request.Params[key];

				if (string.Equals(key, BuildHandler.TargetParam, StringComparison.InvariantCultureIgnoreCase))
				{
					targets = new string[] { value };
				}
				else
				{
					buildPropertyGroup.SetProperty(key, value);
				}
			}

			string buildFileVirtualPath = ConfigurationManager.AppSettings[BuildHandler.BuildFileKey];
			Assert.NonNull(buildFileVirtualPath, BuildHandler.BuildFileKey, "Must be set in appSettings");

			string buildFilePhysicalPath = context.Request.MapPath(buildFileVirtualPath);
			Assert.True(File.Exists(buildFilePhysicalPath), BuildHandler.BuildFileKey, "File must exist");

			ILogger logger = new MessageLogger(context.Response.Output);

			Microsoft.Build.BuildEngine.Engine engine = new Microsoft.Build.BuildEngine.Engine();
			engine.BinPath = RuntimeEnvironment.GetRuntimeDirectory();
			engine.RegisterLogger(logger);

			if (!engine.BuildProjectFile(buildFilePhysicalPath, targets, buildPropertyGroup))
			{
				context.Response.StatusCode = 500;
			}

			engine.UnregisterAllLoggers();
		}

		private class MessageLogger : Logger
		{
			private static readonly MessageImportance[] IgnoreMessageImportance = { MessageImportance.Low };
			private static readonly string[] IgnoreWarningCodes = { "MSB4056" };
			private TextWriter writer;

			public MessageLogger(TextWriter writer)
			{
				Assert.ArgumentNonNull(this.writer = writer, "writer");
			}

			public override void Initialize(IEventSource eventSource)
			{
				eventSource.ErrorRaised += delegate(object sender, BuildErrorEventArgs e) { this.writer.WriteLine(e.Message); };
				eventSource.MessageRaised += delegate(object sender, BuildMessageEventArgs e) { if (Array.IndexOf(MessageLogger.IgnoreMessageImportance, e.Importance) == -1) this.writer.WriteLine(e.Message); };
				eventSource.WarningRaised += delegate(object sender, BuildWarningEventArgs e) { if (Array.IndexOf(MessageLogger.IgnoreWarningCodes, e.Code) == -1) this.writer.WriteLine(e.Message); };
			}
		}
	}
}