using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml;
using System.Xml.Linq;

using Mono.Cecil;

namespace Mono.Documentation.Updater.Frameworks
{

	public class FrameworkIndex
	{
		List<FrameworkEntry> frameworks = new List<FrameworkEntry> ();
        IList<FrameworkEntry> cachedFrameworks;

		string path;

		public FrameworkIndex (string pathToFrameworks, int fxCount, IList<FrameworkEntry> cachedfx) 
		{
			path = pathToFrameworks;
            FrameworksCount = fxCount;
            cachedFrameworks = cachedfx ?? frameworks;
		}

        public int FrameworksCount {
            get; private set;
        }

		public IList<FrameworkEntry> Frameworks {
			get {
				return this.frameworks;
			}
		}

        public FrameworkEntry StartProcessingAssembly (AssemblySet set, AssemblyDefinition assembly, IEnumerable<DocumentationImporter> importers, string Id, string Version)
        {
            if (string.IsNullOrWhiteSpace (this.path))
            {
                set.Framework = FrameworkEntry.Empty;
                return FrameworkEntry.Empty;
            }

            string assemblyPath = assembly.MainModule.FileName;
            string shortPath = GetFrameworkNameFromPath (this.path, assemblyPath);

            var entry = frameworks.FirstOrDefault (f => f.Name.Equals (shortPath));
            if (entry == null)
            {
                entry = new FrameworkEntry (frameworks, FrameworksCount, cachedFrameworks) { Name = shortPath, Importers = importers, Id = Id, Version = Version };
                frameworks.Add (entry);
            }

            set.Framework = entry;
            entry.AddProcessedAssembly (assembly);

            return entry;
        }

        public static string GetFrameworkNameFromPath (string rootpath, string assemblyPath)
        {
            char otherSepChar = '/';
            if (Path.DirectorySeparatorChar == '/')
                otherSepChar = '\\';

            if (rootpath.Contains(otherSepChar))
                rootpath = rootpath.Replace(otherSepChar, Path.DirectorySeparatorChar);

            if (assemblyPath.Contains(otherSepChar))
                assemblyPath = assemblyPath.Replace(otherSepChar, Path.DirectorySeparatorChar);

            var frameworksDirectory = rootpath.EndsWith ("frameworks.xml", StringComparison.OrdinalIgnoreCase)
                                                        ? Path.GetDirectoryName (rootpath) : rootpath;
            string relativePath = assemblyPath.Replace (frameworksDirectory, string.Empty);
            string shortPath = Path.GetDirectoryName (relativePath);
            if (shortPath.StartsWith (Path.DirectorySeparatorChar.ToString (), StringComparison.InvariantCultureIgnoreCase))
                shortPath = shortPath.Substring (1, shortPath.Length - 1);
            return shortPath;
        }

        /// <summary>Writes the framework indices to disk.</summary>
        /// <param name="path">The folder where one file for every FrameworkEntry will be written.</param>
        public void WriteToDisk (string path) 
		{
			if (string.IsNullOrWhiteSpace (this.path))
				return;
			
      string outputPath = Path.Combine (path, Consts.FrameworksIndex);

			if (!Directory.Exists (outputPath))
				Directory.CreateDirectory (outputPath);

			foreach (var fx in this.frameworks)
			{
				XElement frameworkElement = new XElement("Framework", new XAttribute("Name", fx.Name));
				XDocument doc = new XDocument(
					frameworkElement
					);
				if (fx.Version!=null && fx.Id!= null)
				{
					frameworkElement.Add(new XElement("package", new XAttribute("Id", fx.Id),
						new XAttribute("Version", fx.Version)
						));
				}
                if (fx.AssemblyNames.Any())
                {
                    frameworkElement.Add (
                        new XElement (
                            "Assemblies",
                            fx.AssemblyNames.Distinct().Select(an => 
                                                               new XElement("Assembly",
                                                                            new XAttribute("Name", an.Item1),
                                                                            new XAttribute("Version", an.Item2)
                                                                          ))
                                    ));
                }

				frameworkElement.Add(fx.Types.GroupBy(t => t.Namespace)
					.Select(g => new XElement("Namespace",
						new XAttribute("Name", g.Key),
						g.Select(t => new XElement("Type",
							new XAttribute("Name", t.Name),
							new XAttribute("Id", t.Id),
							t.Members.Select(m =>
								new XElement("Member",
									new XAttribute("Id", m))))))));
				// now save the document
				string filePath = Path.Combine (outputPath, fx.Name + ".xml");

				MdocFile.DeleteFile (filePath);

				var settings = new XmlWriterSettings { Indent = true };
				using (var writer = XmlWriter.Create (filePath, settings)) {
					doc.WriteTo (writer);
				}
			}
		}
	}
}