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

namespace Help.HelpSystem
{
    static class HelpManager
    {
        public static List<HelpChapter> Chapters = new List<HelpChapter>();

        public static string DocumentationPath = "";

        public static string GetFullPath(string relative)
        {
            return System.IO.Path.Combine(DocumentationPath, relative);
        }

        public static void Load(string indexfile)
        {
            XmlTextReader reader = new XmlTextReader(indexfile);

            HelpChapter currentChapter = new HelpChapter();
            HelpTopic currentTopic = new HelpTopic();
            bool isTopic = false;

            while (reader.Read())
            {
                switch (reader.NodeType)
                {
                    case XmlNodeType.Element:
                        if (reader.Name == "chapter")
                        {
                            isTopic = false;
                            currentChapter = new HelpChapter();
                        }

                        else if (reader.Name == "topic")
                        {
                            isTopic = true;
                            currentTopic = new HelpTopic();
                        }


                        while (reader.MoveToNextAttribute())
                        {
                            switch (reader.Name)
                            {
                                case "application": if (!isTopic) currentChapter.Application = reader.Value; break;
                                case "title":
                                    if (isTopic) currentTopic.Title = reader.Value;
                                    else currentChapter.Title = reader.Value;
                                    break;

                                case "filename":
                                    if (isTopic) currentTopic.Filename = reader.Value;
                                    else currentChapter.Filename = reader.Value;
                                    break;
                            }
                        }

                        if (isTopic) currentChapter.Topics.Add(currentTopic);

                        break;

                    case XmlNodeType.EndElement:
                        if (reader.Name == "topic") currentChapter.Topics.Add(currentTopic);
                        else if (reader.Name == "chapter") Chapters.Add(currentChapter);

                        break;
                }

            }

            reader.Close();
            DocumentationPath = System.IO.Path.GetDirectoryName(indexfile);
        }

        private static string[] FindInFile(string file, string q)
        {
            int min, max;
            string text = System.IO.File.ReadAllText(file);
            List<string> ret = new List<string>();

            // Remove html tags
            min = text.IndexOf('<');
            max = text.IndexOf('>');
            while (min != -1 && max != -1 && min < max)
            {
                text = text.Remove(min, max - min + 1);
                min = text.IndexOf('<');
                max = text.IndexOf('>');
            }

            // Search each line
            foreach (var line in text.Split('\n', '\r'))
                if (line.ToLower().Contains(q.ToLower())) ret.Add(line.TrimStart(' ', '\t', '\n', '\r'));

            return ret.ToArray();
        }

        public static HelpTopic[] SearchText(string text, HelpChapter chapter)
        {
            var list = new List<HelpTopic>();

            // Make a list of files to be checked
            var temp = new List<HelpTopic>();
            temp.Add(new HelpTopic(chapter.Title, chapter.Filename));
            temp.AddRange(chapter.Topics);

            // Search
            foreach (var top in temp)
            {
                string[] f = FindInFile(GetFullPath(top.Filename), text);
                foreach (var i in f)
                    list.Add(new HelpTopic()
                    {
                        Title = top.Title,
                        Filename = top.Filename,
                        Context = i,
                        IsSearchResult = true
                    });
            }

            return list.ToArray();
        }

        public static HelpTopic[] SearchTitle(string text, HelpChapter chapter)
        {
            return chapter.Topics.Where(x => x.Title.ToLower().Contains(text.ToLower())).ToArray();
        }
    }
}