// ------------------------------------------------------------------------------------------------
// <copyright file="InheritDocumentationComponent.cs" company="Microsoft">
//      Copyright © Microsoft Corporation.
//      This source file is subject to the Microsoft Permissive License.
//      See http://www.microsoft.com/resources/sharedsource/licensingbasics/sharedsourcelicenses.mspx.
//      All other rights reserved.
// </copyright>
// <summary>Contains code that indexes XML comments files for <inheritdoc /> tags, reflection files
// for API information and produces a new XML comments file containing the inherited documentation
// for use by Sandcastle.
// </summary>
// ------------------------------------------------------------------------------------------------
namespace Microsoft.Ddue.Tools
{
    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Xml;
    using System.Xml.XPath;
    using System.Configuration;
    using System.Globalization;
    using Microsoft.Ddue.Tools.CommandLine;
   
    /// <summary>
    /// InheritDocumentationComponent class.
    /// </summary>
    public class InheritDocumentationComponent : CopyComponent
    {
        #region private members
        /// <summary>
        /// XPathExpression for API name.
        /// </summary>
        private static XPathExpression apiNameExpression = XPathExpression.Compile("string(apidata/@name)");

        /// <summary>
        /// XPathExpression for API group.
        /// </summary>
        private static XPathExpression apiGroupExpression = XPathExpression.Compile("string(apidata/@group)");
        
        /// <summary>
        /// XPathExpression for API subgroup.
        /// </summary>
        private static XPathExpression apiSubgroupExpression = XPathExpression.Compile("string(apidata/@subgroup)");

        /// <summary>
        /// XPathExpression for API ancestors.
        /// </summary>
        private static XPathExpression typeExpression = XPathExpression.Compile("family/ancestors/type/@api");

        /// <summary>
        /// XPathExpression for API type interface implementations.
        /// </summary>
        private static XPathExpression interfaceImplementationExpression = XPathExpression.Compile("implements/type/@api");

        /// <summary>
        /// XPathExpression for API containers.
        /// </summary>
        private static XPathExpression containerTypeExpression = XPathExpression.Compile("string(containers/type/@api)");

        /// <summary>
        /// XPathExpression for override members.
        /// </summary>
        private static XPathExpression overrideMemberExpression = XPathExpression.Compile("overrides/member/@api");

        /// <summary>
        /// XPathExpression for API member interface implementaions.
        /// </summary>
        private static XPathExpression interfaceImplementationMemberExpression = XPathExpression.Compile("implements/member/@api");

        /// <summary>
        /// XPathExpression for <inheritdoc /> nodes.
        /// </summary>
        private static XPathExpression inheritDocExpression = XPathExpression.Compile("//inheritdoc");

        /// <summary>
        /// XPathExpression that looks for example, filterpriority, preliminary, remarks, returns, summary, threadsafety and value nodes.
        /// </summary>
        private static XPathExpression tagsExpression = XPathExpression.Compile("example|filterpriority|preliminary|remarks|returns|summary|threadsafety|value");

        /// <summary>
        /// XPathExpression for source nodes.
        /// </summary>
        private static XPathExpression sourceExpression;

        /// <summary>
        /// Document to be parsed.
        /// </summary>
        private XmlDocument sourceDocument;

        /// <summary>
        /// A cache for comment files.
        /// </summary>
        private IndexedDocumentCache index;

        /// <summary>
        /// A cache for reflection files.
        /// </summary>
        private IndexedDocumentCache reflectionIndex;
        #endregion

        #region constructor
        /// <summary>
        /// Creates an instance of InheritDocumentationComponent class.
        /// </summary>
        /// <param name="configuration">Configuration section to be parsed.</param>
        /// <param name="data">A dictionary object with string as key and object as value.</param>
        public InheritDocumentationComponent(XPathNavigator configuration, Dictionary<string, object> data)
            : base(configuration, data)
        {
            // get the copy commands
            XPathNodeIterator copy_nodes = configuration.Select("copy");
            foreach (XPathNavigator copy_node in copy_nodes)
            {
                // get the comments info
                string source_name = copy_node.GetAttribute("name", string.Empty);
		        if (String.IsNullOrEmpty(source_name))
                {
                    throw new ConfigurationErrorsException("Each copy command must specify an index to copy from.");
                }

                // get the reflection info
                string reflection_name = copy_node.GetAttribute("use", String.Empty);
                if (String.IsNullOrEmpty(reflection_name))
                {
                    throw new ConfigurationErrorsException("Each copy command must specify an index to get reflection information from.");
                }
                               
                this.index = (IndexedDocumentCache)data[source_name];
                this.reflectionIndex = (IndexedDocumentCache)data[reflection_name];
             }
        }
        #endregion

        #region methods
        /// <summary>
        /// Deletes the specified node and logs the message.
        /// </summary>
        /// <param name="inheritDocNodeNavigator">navigator for inheritdoc node</param>
        /// <param name="key">Id of the topic specified</param>
        public static void DeleteNode(XPathNavigator inheritDocNodeNavigator, string key)
        {
            ConsoleApplication.WriteMessage(LogLevel.Info, string.Format(CultureInfo.InvariantCulture, "Comments are not found for topic:{0}", key));
            inheritDocNodeNavigator.DeleteSelf();
        }

        /// <summary>
        /// Implement inheritDocumentation.
        /// </summary>
        /// <param name="document">document to be parsed</param>
        /// <param name="key">Id pf the topic specified</param>
        public override void Apply(XmlDocument document, string key) 
        {
            // default selection filter set not to inherit <overloads>.
            sourceExpression = XPathExpression.Compile("*[not(local-name()='overloads')]");
            this.sourceDocument = document;
            this.InheritDocumentation(key);
        }

        /// <summary>
        /// Inherit the documentation.
        /// </summary>
        /// <param name="key">Id of the topic specified</param>
        public void InheritDocumentation(string key)
        {
            foreach (XPathNavigator inheritDocNodeNavigator in this.sourceDocument.CreateNavigator().Select(inheritDocExpression))
            {
                inheritDocNodeNavigator.MoveToParent();

                XPathNodeIterator iterator = (XPathNodeIterator) inheritDocNodeNavigator.CreateNavigator().Evaluate(tagsExpression);
                
                // do not inherit the comments if the tags specified in tagsExpression are already present.
                if (iterator.Count != 0) 
                {
                    inheritDocNodeNavigator.MoveTo(this.sourceDocument.CreateNavigator().SelectSingleNode(inheritDocExpression));
                    inheritDocNodeNavigator.DeleteSelf();
                    continue; 
                }
                     
                inheritDocNodeNavigator.MoveTo(this.sourceDocument.CreateNavigator().SelectSingleNode(inheritDocExpression));

                // Inherit from the specified API [id=cref].
                string cref = inheritDocNodeNavigator.GetAttribute("cref", string.Empty);

                if (!string.IsNullOrEmpty(cref))
                {
                    XPathNavigator contentNodeNavigator = this.index.GetContent(cref);

                    // if no comments were found for the specified api, delete the <inheritdoc /> node,
                    // otherwise update the <inheritdoc /> node with the comments from the specified api.
                    if (contentNodeNavigator == null)
                    {
                        DeleteNode(inheritDocNodeNavigator, cref);
                    }
                    else
                    {
                        this.UpdateNode(inheritDocNodeNavigator, contentNodeNavigator);
                        if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count != 0)
                        {
                            this.InheritDocumentation(cref);
                        }
                    }
                }
                else
                {
                    XPathNavigator reflectionNodeNavigator = this.reflectionIndex.GetContent(key);

                    // no reflection information was found for the api, so delete <inheritdoc /> node.
                    if (reflectionNodeNavigator == null)
                    {
                        DeleteNode(inheritDocNodeNavigator, key);
                        continue;
                    }

                    string group = (string)reflectionNodeNavigator.Evaluate(apiGroupExpression);
                    string subgroup = (string)reflectionNodeNavigator.Evaluate(apiSubgroupExpression);
                                     
                    if (group == "type")
                    {
                        // Inherit from base types
                        XPathNodeIterator typeNodeIterator = (XPathNodeIterator)reflectionNodeNavigator.Evaluate(typeExpression);
                        this.GetComments(typeNodeIterator, inheritDocNodeNavigator);

                        // no <inheritdoc /> nodes were found, so continue with next iteration. Otherwise inherit from interface implementation types.
                        if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count == 0)
                        {
                            continue;
                        }

                        // Inherit from interface implementation types
                        XPathNodeIterator interfaceNodeIterator = (XPathNodeIterator)reflectionNodeNavigator.Evaluate(interfaceImplementationExpression);
                        this.GetComments(interfaceNodeIterator, inheritDocNodeNavigator);
                    }
                    else if (group == "member")
                    {
                        // constructors do not have override member information in reflection files, so search all the base types for a matching signature.
                        if (subgroup == "constructor")
                        {
                            string name = (string)reflectionNodeNavigator.Evaluate(apiNameExpression);
                            string typeApi = (string) reflectionNodeNavigator.Evaluate(containerTypeExpression);

                            // no container type api was found, so delete <inheritdoc /> node.
                            if (string.IsNullOrEmpty(typeApi))
                            {
                                DeleteNode(inheritDocNodeNavigator, key);
                                continue;
                            }

                            reflectionNodeNavigator = this.reflectionIndex.GetContent(typeApi);
                            
                            // no reflection information for container type api was found, so delete <inheritdoc /> node.
                            if (reflectionNodeNavigator == null)
                            {
                                DeleteNode(inheritDocNodeNavigator, key);
                                continue;
                            }

                            XPathNodeIterator containerIterator = reflectionNodeNavigator.Select(typeExpression);
                                                    
                            foreach (XPathNavigator containerNavigator in containerIterator)
                            {
                                string constructorId = string.Format(CultureInfo.InvariantCulture, "M:{0}.{1}", containerNavigator.Value.Substring(2), name.Replace('.', '#'));
                                XPathNavigator contentNodeNavigator = this.index.GetContent(constructorId);

                                if (contentNodeNavigator == null)
                                {
                                    continue;
                                }

                                this.UpdateNode(inheritDocNodeNavigator, contentNodeNavigator);

                                if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count == 0)
                                {
                                    break;
                                }
                                else
                                {
                                    inheritDocNodeNavigator.MoveTo(this.sourceDocument.CreateNavigator().SelectSingleNode(inheritDocExpression));
                                }
                            }
                        }
                        else
                        {
                            // Inherit from override members.
                            XPathNodeIterator memberNodeIterator = (XPathNodeIterator)reflectionNodeNavigator.Evaluate(overrideMemberExpression);
                            this.GetComments(memberNodeIterator, inheritDocNodeNavigator);

                            if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count == 0)
                            {
                                continue;
                            }

                            // Inherit from interface implementations members.
                            XPathNodeIterator interfaceNodeIterator = (XPathNodeIterator)reflectionNodeNavigator.Evaluate(interfaceImplementationMemberExpression);
                            this.GetComments(interfaceNodeIterator, inheritDocNodeNavigator);
                        }
                    }

                    // no comments were found, so delete <iheritdoc /> node.
                    if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count != 0)
                    {
                        DeleteNode(inheritDocNodeNavigator, key);
                    }
                }
            }
        }

        /// <summary>
        /// Updates the node replacing inheritdoc node with comments found.
        /// </summary>
        /// <param name="inheritDocNodeNavigator">Navigator for inheritdoc node</param>
        /// <param name="contentNodeNavigator">Navigator for content</param>
        public void UpdateNode(XPathNavigator inheritDocNodeNavigator, XPathNavigator contentNodeNavigator)
        {
            // retrieve the selection filter if specified.
            string selectValue = inheritDocNodeNavigator.GetAttribute("select", string.Empty);
                        
            if (!string.IsNullOrEmpty(selectValue))
            {
                sourceExpression = XPathExpression.Compile(selectValue);
            }
            
            inheritDocNodeNavigator.MoveToParent();
                        
            if (inheritDocNodeNavigator.LocalName != "comments" && inheritDocNodeNavigator.LocalName != "element")
            {
                sourceExpression = XPathExpression.Compile(inheritDocNodeNavigator.LocalName);
            }
            else 
            {
                inheritDocNodeNavigator.MoveTo(this.sourceDocument.CreateNavigator().SelectSingleNode(inheritDocExpression)); 
            }
           
            XPathNodeIterator sources = (XPathNodeIterator) contentNodeNavigator.CreateNavigator().Evaluate(sourceExpression);
            inheritDocNodeNavigator.DeleteSelf();

            // append the source nodes to the target node
            foreach (XPathNavigator source in sources)
            {
               inheritDocNodeNavigator.AppendChild(source);
            }
        }

        /// <summary>
        /// Gets the comments for inheritdoc node.
        /// </summary>
        /// <param name="iterator">Iterator for API information</param>
        /// <param name="inheritDocNodeNavigator">Navigator for inheritdoc node</param>
        public void GetComments(XPathNodeIterator iterator, XPathNavigator inheritDocNodeNavigator)
        {
            foreach (XPathNavigator navigator in iterator)
            {
                XPathNavigator contentNodeNavigator = this.index.GetContent(navigator.Value);

                if (contentNodeNavigator == null)
                {
                    continue;
                }

                this.UpdateNode(inheritDocNodeNavigator, contentNodeNavigator);

                if (this.sourceDocument.CreateNavigator().Select(inheritDocExpression).Count == 0)
                {
                    break;
                }
                else
                {
                    inheritDocNodeNavigator.MoveTo(this.sourceDocument.CreateNavigator().SelectSingleNode(inheritDocExpression));
                }
            }
        }
        #endregion
    }
}