#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2014 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Core.Networks;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Scripting;
using Microsoft.CSharp;
using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;

namespace HeuristicLab.Networks.Programmable {
  [Item("ProgrammableNetworkItem", "Abstract base class for programmable items of a network.")]
  [StorableClass]
  public abstract class ProgrammableNetworkItem : Item, IProgrammableNetworkItem {
    public static new Image StaticItemImage {
      get { return HeuristicLab.Common.Resources.VSImageLibrary.Class; }
    }

    #region Item Members
    public override string ItemName {
      get { return CompiledNetworkItem.ItemName; }
    }
    public override string ItemDescription {
      get { return CompiledNetworkItem.ItemDescription; }
    }
    public override Image ItemImage {
      get { return CompiledNetworkItem.ItemImage; }
    }
    #endregion

    #region NamedItem Members
    [Storable]
    private string name;
    public string Name {
      get { return CompiledNetworkItem.Name; }
      set { CompiledNetworkItem.Name = value; }
    }
    public bool CanChangeName {
      get { return CompiledNetworkItem.CanChangeName; }
    }
    [Storable]
    private string description;
    public string Description {
      get { return CompiledNetworkItem.Description; }
      set { CompiledNetworkItem.Description = value; }
    }
    public virtual bool CanChangeDescription {
      get { return CompiledNetworkItem.CanChangeDescription; }
    }
    public event EventHandler<CancelEventArgs<string>> NameChanging;
    private void OnNameChanging(CancelEventArgs<string> e) {
      var handler = NameChanging;
      if (handler != null) handler(this, e);
    }
    public event EventHandler NameChanged;
    private void OnNameChanged() {
      var handler = NameChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler DescriptionChanged;
    private void OnDescriptionChanged() {
      var handler = DescriptionChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    #endregion

    #region NetworkItem Members
    public INetworkItem Parent {
      get { return CompiledNetworkItem.Parent; }
    }
    public IEnumerable<INetworkItem> Children {
      get { return CompiledNetworkItem.Children; }
    }
    #endregion

    protected virtual string CodeTemplate {
      get { return ReadCodeTemplate("HeuristicLab.Networks.Programmable.ProgrammableNetworkItemCode.cs"); }
    }
    [Storable]
    private string code;
    public string Code {
      get { return code; }
      set {
        if (!CanChangeCode) throw new NotSupportedException("Code cannot be changed.");
        if (value != code) {
          code = value;
          OnCodeChanged();
        }
      }
    }
    private CompilerErrorCollection compileErrors;
    public CompilerErrorCollection CompileErrors {
      get { return compileErrors; }
      protected set {
        compileErrors = value;
        OnCompileErrorsChanged();
      }
    }
    public virtual bool CanChangeCode {
      get { return false; }
    }
    [Storable]
    private VariableStore variableStore;
    public VariableStore VariableStore {
      get { return variableStore; }
    }

    private Type compiledNetworkItemType;
    private CompiledProgrammableNetworkItem compiledNetworkItem;
    protected CompiledProgrammableNetworkItem CompiledNetworkItem {
      get {
        if (compiledNetworkItem == null)
          CompiledNetworkItem = (CompiledProgrammableNetworkItem)Activator.CreateInstance(compiledNetworkItemType, this);
        return compiledNetworkItem;
      }
      private set {
        if (compiledNetworkItem != value) {
          if (compiledNetworkItem != null) {
            DeregisterCompiledNetworkItemEvents();
            compiledNetworkItem.DeregisterEvents();
          }
          compiledNetworkItem = value;
          if (compiledNetworkItem != null) {
            RegisterCompiledNetworkItemEvents();
            compiledNetworkItem.RegisterEvents();
          }
          OnToStringChanged();
          OnItemImageChanged();
          OnNameChanged();
          OnDescriptionChanged();
        }
      }
    }

    [StorableConstructor]
    protected ProgrammableNetworkItem(bool deserializing) : base(deserializing) { }
    protected ProgrammableNetworkItem(ProgrammableNetworkItem original, Cloner cloner)
      : base(original, cloner) {
      // name and description are cloned in CompiledProgrammableNetworkItem
      code = original.code;
      if (original.compileErrors != null)
        compileErrors = new CompilerErrorCollection(original.compileErrors);
      variableStore = cloner.Clone(original.variableStore);
      CompiledNetworkItem = cloner.Clone(original.compiledNetworkItem);
    }
    protected ProgrammableNetworkItem()
      : base() {
      name = "ProgrammableNetworkItem";
      description = string.Empty;
      code = CodeTemplate;
      variableStore = new VariableStore();
      Compile();
    }
    protected ProgrammableNetworkItem(string name)
      : base() {
      this.name = string.IsNullOrEmpty(name) ? string.Empty : name;
      description = string.Empty;
      code = CodeTemplate;
      variableStore = new VariableStore();
      Compile();
    }
    protected ProgrammableNetworkItem(string name, string description)
      : base() {
      this.name = string.IsNullOrEmpty(name) ? string.Empty : name;
      this.description = string.IsNullOrEmpty(description) ? string.Empty : description;
      code = CodeTemplate;
      variableStore = new VariableStore();
      Compile();
    }

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      Compile();
    }

    public override string ToString() {
      return CompiledNetworkItem.ToString();
    }

    #region Compilation
    public virtual void Compile() {
      var codeProvider = new CSharpCodeProvider(
        new Dictionary<string, string> {
          {"CompilerVersion", "v4.0"}, // support C# 4.0 syntax
        }
      );
      var compilerParams = new CompilerParameters {
        GenerateExecutable = false,
        GenerateInMemory = true,
        IncludeDebugInformation = true,
        WarningLevel = 4
      };
      compilerParams.ReferencedAssemblies.AddRange(
        GetAssemblies().Select(a => a.Location).ToArray()
      );
      var results = codeProvider.CompileAssemblyFromSource(compilerParams, code);
      CompileErrors = results.Errors;
      if (results.Errors.HasErrors) {
        var sb = new StringBuilder();
        foreach (CompilerError error in results.Errors) {
          sb.Append(error.Line).Append(':')
            .Append(error.Column).Append(": ")
            .AppendLine(error.ErrorText);
        }
        throw new InvalidOperationException(string.Format("Compilation of \"{0}\" failed:{1}{2}",
          Name, Environment.NewLine, sb.ToString()));
      }
      compiledNetworkItemType = results.CompiledAssembly.GetTypes()
          .Single(x => typeof(CompiledProgrammableNetworkItem).IsAssignableFrom(x));
      CompiledNetworkItem = null;
    }
    public virtual IEnumerable<Assembly> GetAssemblies() {
      var assemblies = AppDomain.CurrentDomain.GetAssemblies()
        .Where(a => !a.IsDynamic && File.Exists(a.Location))
        .ToList();
      assemblies.Add(typeof(Microsoft.CSharp.RuntimeBinder.Binder).Assembly);  // for dlr functionality
      return assemblies;
    }
    #endregion

    public event EventHandler CodeChanged;
    protected virtual void OnCodeChanged() {
      var handler = CodeChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler CompileErrorsChanged;
    protected virtual void OnCompileErrorsChanged() {
      var handler = CompileErrorsChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    #region CompiledNetworkItem Events
    protected virtual void RegisterCompiledNetworkItemEvents() {
      CompiledNetworkItem.ToStringChanged += CompiledNetworkItem_ToStringChanged;
      CompiledNetworkItem.ItemImageChanged += CompiledNetworkItem_ItemImageChanged;
      CompiledNetworkItem.NameChanging += CompiledNetworkItem_NameChanging;
      CompiledNetworkItem.NameChanged += CompiledNetworkItem_NameChanged;
      CompiledNetworkItem.DescriptionChanged += CompiledNetworkItem_DescriptionChanged;
    }
    protected virtual void DeregisterCompiledNetworkItemEvents() {
      CompiledNetworkItem.ToStringChanged -= CompiledNetworkItem_ToStringChanged;
      CompiledNetworkItem.ItemImageChanged -= CompiledNetworkItem_ItemImageChanged;
      CompiledNetworkItem.NameChanging -= CompiledNetworkItem_NameChanging;
      CompiledNetworkItem.NameChanged -= CompiledNetworkItem_NameChanged;
      CompiledNetworkItem.DescriptionChanged -= CompiledNetworkItem_DescriptionChanged;
    }
    private void CompiledNetworkItem_ToStringChanged(object sender, EventArgs e) {
      OnToStringChanged();
    }
    private void CompiledNetworkItem_ItemImageChanged(object sender, EventArgs e) {
      OnItemImageChanged();
    }
    private void CompiledNetworkItem_NameChanging(object sender, CancelEventArgs<string> e) {
      OnNameChanging(e);
    }
    private void CompiledNetworkItem_NameChanged(object sender, EventArgs e) {
      OnNameChanged();
    }
    private void CompiledNetworkItem_DescriptionChanged(object sender, EventArgs e) {
      OnDescriptionChanged();
    }
    #endregion

    #region CompiledProgrammableNetworkItem
    [Item("CompiledProgrammableNetworkItem", "Abstract base class for compiled programmable items of a network.")]
    public abstract class CompiledProgrammableNetworkItem : Item, INetworkItem {
      public static new Image StaticItemImage {
        get { return HeuristicLab.Common.Resources.VSImageLibrary.Class; }
      }

      #region NamedItem Members
      public string Name {
        get { return Context.name; }
        set {
          if (!CanChangeName) throw new NotSupportedException("Name cannot be changed.");
          if (!(Context.name.Equals(value) || (value == null) && (Context.name == string.Empty))) {
            CancelEventArgs<string> e = value == null ? new CancelEventArgs<string>(string.Empty) : new CancelEventArgs<string>(value);
            OnNameChanging(e);
            if (!e.Cancel) {
              Context.name = value == null ? string.Empty : value;
              OnNameChanged();
            }
          }
        }
      }
      public virtual bool CanChangeName {
        get { return true; }
      }
      public string Description {
        get { return Context.description; }
        set {
          if (!CanChangeDescription) throw new NotSupportedException("Description cannot be changed.");
          if (!(Context.description.Equals(value) || (value == null) && (Context.description == string.Empty))) {
            Context.description = value == null ? string.Empty : value;
            OnDescriptionChanged();
          }
        }
      }
      public virtual bool CanChangeDescription {
        get { return true; }
      }

      public event EventHandler<CancelEventArgs<string>> NameChanging;
      protected virtual void OnNameChanging(CancelEventArgs<string> e) {
        var handler = NameChanging;
        if (handler != null) handler(this, e);
      }
      public event EventHandler NameChanged;
      protected virtual void OnNameChanged() {
        var handler = NameChanged;
        if (handler != null) handler(this, EventArgs.Empty);
        OnToStringChanged();
      }
      public event EventHandler DescriptionChanged;
      protected virtual void OnDescriptionChanged() {
        var handler = DescriptionChanged;
        if (handler != null) handler(this, EventArgs.Empty);
      }
      #endregion

      #region NetworkItem Members
      private INetworkItem parent;
      public INetworkItem Parent {
        get { return parent; }
        protected set {
          if (value != parent) {
            parent = value;
          }
        }
      }
      public virtual IEnumerable<INetworkItem> Children {
        get { return Enumerable.Empty<INetworkItem>(); }
      }
      #endregion

      protected ProgrammableNetworkItem Context { get; private set; }
      private Variables variables;
      protected Variables Variables {
        get {
          if (variables == null) variables = new Variables(Context.variableStore);
          return variables;
        }
      }
      protected dynamic Vars {
        get { return Variables; }
      }

      protected CompiledProgrammableNetworkItem(CompiledProgrammableNetworkItem original, Cloner cloner)
        : base(original, cloner) {
        Context = cloner.Clone(original.Context);
        Context.name = original.Context.name;
        Context.description = original.Context.description;
      }
      protected CompiledProgrammableNetworkItem(ProgrammableNetworkItem context)
        : base() {
        Context = context;
      }

      public virtual void Initialize() {
        Variables.Clear();
      }

      public override string ToString() {
        return Name;
      }

      #region Events
      public virtual void RegisterEvents() { }
      public virtual void DeregisterEvents() { }
      #endregion
    }
    #endregion

    #region Helpers
    protected virtual string ReadCodeTemplate(string templateName) {
      using (var stream = Assembly.GetAssembly(this.GetType()).GetManifestResourceStream(templateName))
      using (var reader = new StreamReader(stream)) {
        return reader.ReadToEnd();
      }
    }
    #endregion
  }
}