#region License Information
// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

/* HeuristicLab
 * Copyright (C) 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 System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Media;
using ICSharpCode.AvalonEdit.Highlighting;
using ICSharpCode.AvalonEdit.Utils;
using ICSharpCode.NRefactory.Editor;
using ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.Xml;

namespace HeuristicLab.CodeEditor {
  /// <summary>
  /// Builds a FlowDocument for XML documentation.
  /// </summary>
  public class CSharpDocumentationBuilder {
    const string SyntaxHighlighting = "C#";
    const string FontFamily = "Consolas";
    const double FontSize = 13.0;
    const string MsdnLibraryUrl = "http://msdn.microsoft.com/library/";
    readonly FlowDocument flowDocument;
    readonly IAmbience ambience;
    BlockCollection blockCollection;
    InlineCollection inlineCollection;

    public CSharpDocumentationBuilder(IAmbience ambience) {
      this.ambience = ambience;
      this.flowDocument = new FlowDocument();
      this.blockCollection = flowDocument.Blocks;

      this.ShowSummary = true;
      this.ShowAllParameters = true;
      this.ShowReturns = true;
      this.ShowThreadSafety = true;
      this.ShowExceptions = true;
      this.ShowTypeParameters = true;

      this.ShowExample = true;
      this.ShowPreliminary = true;
      this.ShowSeeAlso = true;
      this.ShowValue = true;
      this.ShowPermissions = true;
      this.ShowRemarks = true;
    }

    public FlowDocument CreateFlowDocument() {
      FlushAddedText(true);
      flowDocument.FontSize = FontSize;
      return flowDocument;
    }

    public bool ShowExceptions { get; set; }
    public bool ShowPermissions { get; set; }
    public bool ShowExample { get; set; }
    public bool ShowPreliminary { get; set; }
    public bool ShowRemarks { get; set; }
    public bool ShowSummary { get; set; }
    public bool ShowReturns { get; set; }
    public bool ShowSeeAlso { get; set; }
    public bool ShowThreadSafety { get; set; }
    public bool ShowTypeParameters { get; set; }
    public bool ShowValue { get; set; }
    public bool ShowAllParameters { get; set; }

    /// <summary>
    /// Gets/Sets the name of the parameter that should be shown.
    /// </summary>
    public string ParameterName { get; set; }

    public void AddDocumentationElement(XmlDocumentationElement element) {
      if (element == null)
        throw new ArgumentNullException("element");
      if (element.IsTextNode) {
        AddText(element.TextContent);
        return;
      }
      switch (element.Name) {
        case "b":
          AddSpan(new Bold(), element.Children);
          break;
        case "i":
          AddSpan(new Italic(), element.Children);
          break;
        case "c":
          AddSpan(new Span { FontFamily = GetCodeFont() }, element.Children);
          break;
        case "code":
          AddCodeBlock(element.TextContent);
          break;
        case "example":
          if (ShowExample)
            AddSection("Example: ", element.Children);
          break;
        case "exception":
          if (ShowExceptions)
            AddException(element.ReferencedEntity, element.Children);
          break;
        case "list":
          AddList(element.GetAttribute("type"), element.Children);
          break;
        //case "note":
        //	throw new NotImplementedException();
        case "para":
          AddParagraph(new Paragraph { Margin = new Thickness(0, 5, 0, 5) }, element.Children);
          break;
        case "param":
          if (ShowAllParameters || (ParameterName != null && ParameterName == element.GetAttribute("name")))
            AddParam(element.GetAttribute("name"), element.Children);
          break;
        case "paramref":
          AddParamRef(element.GetAttribute("name"));
          break;
        case "permission":
          if (ShowPermissions)
            AddPermission(element.ReferencedEntity, element.Children);
          break;
        case "preliminary":
          if (ShowPreliminary)
            AddPreliminary(element.Children);
          break;
        case "remarks":
          if (ShowRemarks)
            AddSection("Remarks: ", element.Children);
          break;
        case "returns":
          if (ShowReturns)
            AddSection("Returns: ", element.Children);
          break;
        case "see":
          AddSee(element);
          break;
        case "seealso":
          if (inlineCollection != null)
            AddSee(element);
          else if (ShowSeeAlso)
            AddSection(new Run("See also: "), () => AddSee(element));
          break;
        case "summary":
          if (ShowSummary)
            AddSection("Summary: ", element.Children);
          break;
        case "threadsafety":
          if (ShowThreadSafety)
            AddThreadSafety(ParseBool(element.GetAttribute("static")), ParseBool(element.GetAttribute("instance")), element.Children);
          break;
        case "typeparam":
          if (ShowTypeParameters)
            AddSection("Type parameter " + element.GetAttribute("name") + ": ", element.Children);
          break;
        case "typeparamref":
          AddText(element.GetAttribute("name"));
          break;
        case "value":
          if (ShowValue)
            AddSection("Value: ", element.Children);
          break;
        case "exclude":
        case "filterpriority":
        case "overloads":
          // ignore children
          break;
        case "br":
          AddLineBreak();
          break;
        default:
          foreach (var child in element.Children)
            AddDocumentationElement(child);
          break;
      }
    }

    void AddList(string type, IEnumerable<XmlDocumentationElement> items) {
      List list = new List();
      AddBlock(list);
      list.Margin = new Thickness(0, 5, 0, 5);
      if (type == "number")
        list.MarkerStyle = TextMarkerStyle.Decimal;
      else if (type == "bullet")
        list.MarkerStyle = TextMarkerStyle.Disc;
      var oldBlockCollection = blockCollection;
      try {
        foreach (var itemElement in items) {
          if (itemElement.Name == "listheader" || itemElement.Name == "item") {
            ListItem item = new ListItem();
            blockCollection = item.Blocks;
            inlineCollection = null;
            foreach (var prop in itemElement.Children) {
              AddDocumentationElement(prop);
            }
            FlushAddedText(false);
            list.ListItems.Add(item);
          }
        }
      } finally {
        blockCollection = oldBlockCollection;
      }
    }

    public void AddCodeBlock(string textContent, bool keepLargeMargin = false) {
      var document = new ReadOnlyDocument(textContent);
      var highlightingDefinition = HighlightingManager.Instance.GetDefinition(SyntaxHighlighting);

      var block = DocumentPrinter.ConvertTextDocumentToBlock(document, highlightingDefinition);
      block.FontFamily = GetCodeFont();
      if (!keepLargeMargin)
        block.Margin = new Thickness(0, 6, 0, 6);
      AddBlock(block);
    }

    public void AddSignatureBlock(string signature, int currentParameterOffset, int currentParameterLength, string currentParameterName) {
      ParameterName = currentParameterName;
      var document = new ReadOnlyDocument(signature);
      var highlightingDefinition = HighlightingManager.Instance.GetDefinition(SyntaxHighlighting);

      var richText = DocumentPrinter.ConvertTextDocumentToRichText(document, highlightingDefinition).ToRichTextModel();
      richText.SetFontWeight(currentParameterOffset, currentParameterLength, FontWeights.Bold);
      var block = new Paragraph();
      block.Inlines.AddRange(richText.CreateRuns(document));
      block.FontFamily = GetCodeFont();
      block.TextAlignment = TextAlignment.Left;
      AddBlock(block);
    }

    bool? ParseBool(string input) {
      bool result;
      if (bool.TryParse(input, out result))
        return result;
      else
        return null;
    }

    void AddThreadSafety(bool? staticThreadSafe, bool? instanceThreadSafe, IEnumerable<XmlDocumentationElement> children) {
      AddSection(
        new Run("Thread-safety: "),
        delegate {
          if (staticThreadSafe == true)
            AddText("Any public static members of this type are thread safe. ");
          else if (staticThreadSafe == false)
            AddText("The static members of this type are not thread safe. ");

          if (instanceThreadSafe == true)
            AddText("Any public instance members of this type are thread safe. ");
          else if (instanceThreadSafe == false)
            AddText("Any instance members are not guaranteed to be thread safe. ");

          foreach (var child in children)
            AddDocumentationElement(child);
        });
    }

    FontFamily GetCodeFont() {
      return new FontFamily(FontFamily);
    }

    void AddException(IEntity referencedEntity, IList<XmlDocumentationElement> children) {
      Span span = new Span();
      if (referencedEntity != null)
        span.Inlines.Add(ConvertReference(referencedEntity));
      else
        span.Inlines.Add("Exception");
      span.Inlines.Add(": ");
      AddSection(span, children);
    }


    void AddPermission(IEntity referencedEntity, IList<XmlDocumentationElement> children) {
      Span span = new Span();
      span.Inlines.Add("Permission");
      if (referencedEntity != null) {
        span.Inlines.Add(" ");
        span.Inlines.Add(ConvertReference(referencedEntity));
      }
      span.Inlines.Add(": ");
      AddSection(span, children);
    }

    Inline ConvertReference(IEntity referencedEntity) {
      var h = new Hyperlink(new Run(ambience.ConvertSymbol(referencedEntity)));
      h.Click += CreateNavigateOnClickHandler(referencedEntity);
      return h;
    }

    void AddParam(string name, IEnumerable<XmlDocumentationElement> children) {
      Span span = new Span();
      span.Inlines.Add(new Run(name ?? string.Empty) { FontStyle = FontStyles.Italic });
      span.Inlines.Add(": ");
      AddSection(span, children);
    }

    void AddParamRef(string name) {
      if (name != null) {
        AddInline(new Run(name) { FontStyle = FontStyles.Italic });
      }
    }

    void AddPreliminary(IEnumerable<XmlDocumentationElement> children) {
      if (children.Any()) {
        foreach (var child in children)
          AddDocumentationElement(child);
      } else {
        AddText("[This is preliminary documentation and subject to change.]");
      }
    }

    void AddSee(XmlDocumentationElement element) {
      IEntity referencedEntity = element.ReferencedEntity;
      if (referencedEntity != null) {
        if (element.Children.Any()) {
          Hyperlink link = new Hyperlink();
          link.Click += CreateNavigateOnClickHandler(referencedEntity);
          AddSpan(link, element.Children);
        } else {
          AddInline(ConvertReference(referencedEntity));
        }
      } else if (element.GetAttribute("langword") != null) {
        AddInline(new Run(element.GetAttribute("langword")) { FontFamily = GetCodeFont() });
      } else if (element.GetAttribute("href") != null) {
        Uri uri;
        if (Uri.TryCreate(element.GetAttribute("href"), UriKind.Absolute, out uri)) {
          if (element.Children.Any()) {
            AddSpan(new Hyperlink { NavigateUri = uri }, element.Children);
          } else {
            AddInline(new Hyperlink(new Run(element.GetAttribute("href"))) { NavigateUri = uri });
          }
        }
      } else {
        // Invalid reference: print the cref value
        AddText(element.GetAttribute("cref"));
      }
    }

    RoutedEventHandler CreateNavigateOnClickHandler(IEntity referencedEntity) {
      return delegate(object sender, RoutedEventArgs e) {
        Process.Start(MsdnLibraryUrl + referencedEntity.FullName);
        e.Handled = true;
      };
    }

    void AddSection(string title, IEnumerable<XmlDocumentationElement> children) {
      AddSection(new Run(title), children);
    }

    void AddSection(Inline title, IEnumerable<XmlDocumentationElement> children) {
      AddSection(
        title, delegate {
        foreach (var child in children)
          AddDocumentationElement(child);
      });
    }

    void AddSection(Inline title, Action addChildren) {
      var section = new Section();
      AddBlock(section);
      var oldBlockCollection = blockCollection;
      try {
        blockCollection = section.Blocks;
        inlineCollection = null;

        if (title != null)
          AddInline(new Bold(title));

        addChildren();
        FlushAddedText(false);
      } finally {
        blockCollection = oldBlockCollection;
        inlineCollection = null;
      }
    }

    void AddParagraph(Paragraph para, IEnumerable<XmlDocumentationElement> children) {
      AddBlock(para);
      try {
        inlineCollection = para.Inlines;

        foreach (var child in children)
          AddDocumentationElement(child);
        FlushAddedText(false);
      } finally {
        inlineCollection = null;
      }
    }

    void AddSpan(Span span, IEnumerable<XmlDocumentationElement> children) {
      AddInline(span);
      var oldInlineCollection = inlineCollection;
      try {
        inlineCollection = span.Inlines;
        foreach (var child in children)
          AddDocumentationElement(child);
        FlushAddedText(false);
      } finally {
        inlineCollection = oldInlineCollection;
      }
    }

    public void AddInline(Inline inline) {
      FlushAddedText(false);
      if (inlineCollection == null) {
        var para = new Paragraph();
        para.Margin = new Thickness(0, 0, 0, 5);
        inlineCollection = para.Inlines;
        AddBlock(para);
      }
      inlineCollection.Add(inline);
      ignoreWhitespace = false;
    }

    public void AddBlock(Block block) {
      FlushAddedText(true);
      blockCollection.Add(block);
    }

    StringBuilder addedText = new StringBuilder();
    bool ignoreWhitespace;

    public void AddLineBreak() {
      TrimEndOfAddedText();
      addedText.AppendLine();
      ignoreWhitespace = true;
    }

    public void AddText(string textContent) {
      if (string.IsNullOrEmpty(textContent))
        return;
      for (int i = 0; i < textContent.Length; i++) {
        char c = textContent[i];
        if (c == '\n' && IsEmptyLineBefore(textContent, i)) {
          AddLineBreak(); // empty line -> line break
        } else if (char.IsWhiteSpace(c)) {
          // any whitespace sequence gets converted to a single space (like HTML)
          if (!ignoreWhitespace) {
            addedText.Append(' ');
            ignoreWhitespace = true;
          }
        } else {
          addedText.Append(c);
          ignoreWhitespace = false;
        }
      }
    }

    bool IsEmptyLineBefore(string text, int i) {
      // Skip previous whitespace
      do {
        i--;
      } while (i >= 0 && (text[i] == ' ' || text[i] == '\r'));
      // Check if previous non-whitespace char is \n
      return i >= 0 && text[i] == '\n';
    }

    void TrimEndOfAddedText() {
      while (addedText.Length > 0 && addedText[addedText.Length - 1] == ' ') {
        addedText.Length--;
      }
    }

    void FlushAddedText(bool trim) {
      if (trim) // trim end of current text element
        TrimEndOfAddedText();
      if (addedText.Length == 0)
        return;
      string text = addedText.ToString();
      addedText.Length = 0;
      AddInline(new Run(text));
      ignoreWhitespace = trim; // trim start of next text element
    }
  }
}