using System;
using System.Collections.Generic;
using Mono.Fuse;
using System.Reflection;
using Mono.Unix.Native;
using System.Runtime.InteropServices;

class TypeNavigator : FileSystem
{
	Dictionary<string,Assembly> assemblies;
	Dictionary<string,IEnumerable<FileSystemEntry>> assembly_results = new Dictionary<string,IEnumerable<FileSystemEntry>>();
	
	public TypeNavigator ()
	{
		assemblies = new Dictionary<string,Assembly> ();

		Assembly a = Assembly.Load ("mscorlib");
		assemblies [a.GetName().Name] = a;
	}

	protected override Errno OnReadDirectory (string path, OpenedPathInfo fi, out IEnumerable<FileSystemEntry> paths)
	{
		if (path == "/"){
			paths = GetRootEntries ();

			return 0;
		}
		path = path.Substring (1);
		string [] elements = path.Split (new char [] { '/' });

		try {
			if (elements.Length == 1){
				string key = elements [0];
				Assembly ass = assemblies [key];
				if (ass == null){
					paths = null;
					return Errno.ENOENT;
				}
				if (assembly_results.ContainsKey (key))
					paths = assembly_results [key];
				else {
					paths = assembly_results [key] = GetTypes (ass);
				}
				return 0;
			}
			if (elements.Length == 2){
				Assembly ass = assemblies [elements [0]];
				if (ass != null){
					Type t = ass.GetType (elements [1]);
					if (t != null){
						paths = GetTypeMembers (t);
						return 0;
					}
				}
			}
			
		} catch (Exception e) {
			Console.WriteLine ("Exception: {0}", e.ToString ());
		}
		paths = null;
		return Errno.ENOENT;
	}

	private IEnumerable<FileSystemEntry> GetRootEntries ()
	{
		yield return ".";
		yield return "..";
		foreach (string val in assemblies.Keys){
			Console.WriteLine ("  {0}", val);
			yield return val;
		}
	}

	private IEnumerable<FileSystemEntry> GetTypes (Assembly ass)
	{
		yield return ".";
		yield return "..";
		foreach (Type t in ass.GetTypes())
			yield return t.FullName;
	}

	private IEnumerable<FileSystemEntry> GetTypeMembers (Type t)
	{
		yield return ".";
		yield return "..";
		
		MemberInfo [] mi = t.GetMembers ();
		foreach (MemberInfo m in mi)
			yield return m.Name;
	}
	
	protected override Errno OnGetPathStatus (string path, ref Stat stbuf)
	{
		int sep = 0;
		
		foreach (char c in path){
			if (c == '/')
				sep++;
		}
		
		stbuf = new Stat ();

		if (sep < 3){
			stbuf.st_mode = FilePermissions.S_IFDIR | NativeConvert.FromOctalPermissionString ("0755");
			stbuf.st_nlink = 1;
		} else {
			stbuf.st_mode = FilePermissions.S_IFREG | NativeConvert.FromOctalPermissionString ("0444");
			stbuf.st_nlink = 1;
		}
		stbuf.st_size = 0;

		return 0;
	}
	
	public static void Main (string [] args)
	{
		if (args.Length < 1){
			Console.WriteLine ("Error: must specify a directory to mount at");
			return;
		}
		
		using (TypeNavigator t = new TypeNavigator ()){
			t.MountPoint = args [0];
			t.Start ();
		}
	}
}