using System;
using System.Text.RegularExpressions;
using MediaBrowser.Controller.IO;

namespace MediaBrowser.TV
{
    public static class TVUtils
    {
        /// <summary>
        /// A season folder must contain one of these somewhere in the name
        /// </summary>
        private static string[] SeasonFolderNames = new string[] { 
            "season",
            "sæson",
            "temporada",
            "saison",
            "staffel"
        };

        /// <summary>
        /// Used to detect paths that represent episodes, need to make sure they don't also
        /// match movie titles like "2001 A Space..."
        /// Currently we limit the numbers here to 2 digits to try and avoid this
        /// </summary>
        /// <remarks>
        /// The order here is important, if the order is changed some of the later
        /// ones might incorrectly match things that higher ones would have caught.
        /// The most restrictive expressions should appear first
        /// </remarks>
        private static readonly Regex[] episodeExpressions = new Regex[] {
                        new Regex(@".*\\[s|S]?(?<seasonnumber>\d{1,2})[x|X](?<epnumber>\d{1,3})[^\\]*$", RegexOptions.Compiled),   // 01x02 blah.avi S01x01 balh.avi
                        new Regex(@".*\\[s|S](?<seasonnumber>\d{1,2})x?[e|E](?<epnumber>\d{1,3})[^\\]*$", RegexOptions.Compiled), // S01E02 blah.avi, S01xE01 blah.avi
                        new Regex(@".*\\(?<seriesname>[^\\]*)[s|S]?(?<seasonnumber>\d{1,2})[x|X](?<epnumber>\d{1,3})[^\\]*$", RegexOptions.Compiled),   // 01x02 blah.avi S01x01 balh.avi
                        new Regex(@".*\\(?<seriesname>[^\\]*)[s|S](?<seasonnumber>\d{1,2})[x|X|\.]?[e|E](?<epnumber>\d{1,3})[^\\]*$", RegexOptions.Compiled) // S01E02 blah.avi, S01xE01 blah.avi
        };
        /// <summary>
        /// To avoid the following matching movies they are only valid when contained in a folder which has been matched as a being season
        /// </summary>
        private static readonly Regex[] episodeExpressionsInASeasonFolder = new Regex[] {
                        new Regex(@".*\\(?<epnumber>\d{1,2})\s?-\s?[^\\]*$", RegexOptions.Compiled), // 01 - blah.avi, 01-blah.avi
                        new Regex(@".*\\(?<epnumber>\d{1,2})[^\d\\]*[^\\]*$", RegexOptions.Compiled), // 01.avi, 01.blah.avi "01 - 22 blah.avi" 
                        new Regex(@".*\\(?<seasonnumber>\d)(?<epnumber>\d{1,2})[^\d\\]+[^\\]*$", RegexOptions.Compiled), // 01.avi, 01.blah.avi
                        new Regex(@".*\\\D*\d+(?<epnumber>\d{2})", RegexOptions.Compiled) // hell0 - 101 -  hello.avi

        };

        public static int? GetSeasonNumberFromPath(string path)
        {
            // Look for one of the season folder names
            foreach (string name in SeasonFolderNames)
            {
                int index = path.IndexOf(name, StringComparison.OrdinalIgnoreCase);

                if (index != -1)
                {
                    return GetSeasonNumberFromPathSubstring(path.Substring(index + name.Length));
                }
            }

            return null;
        }

        /// <summary>
        /// Extracts the season number from the second half of the Season folder name (everything after "Season", or "Staffel")
        /// </summary>
        private static int? GetSeasonNumberFromPathSubstring(string path)
        {
            int numericStart = -1;
            int length = 0;

            // Find out where the numbers start, and then keep going until they end
            for (int i = 0; i < path.Length; i++)
            {
                if (char.IsNumber(path, i))
                {
                    if (numericStart == -1)
                    {
                        numericStart = i;
                    }
                    length++;
                }
                else if (numericStart != -1)
                {
                    break;
                }
            }

            if (numericStart == -1)
            {
                return null;
            }

            return int.Parse(path.Substring(numericStart, length));
        }

        public static bool IsSeasonFolder(string path)
        {
            return GetSeasonNumberFromPath(path) != null;
        }

        public static bool IsSeriesFolder(string path, WIN32_FIND_DATA[] fileSystemChildren)
        {
            // A folder with more than 3 non-season folders in will not becounted as a series
            int nonSeriesFolders = 0;

            for (int i = 0; i < fileSystemChildren.Length; i++)
            {
                var child = fileSystemChildren[i];

                if (child.IsHidden || child.IsSystemFile)
                {
                    continue;
                }

                if (child.IsDirectory)
                {
                    if (IsSeasonFolder(child.Path))
                    {
                        return true;
                    }
                    else
                    {
                        nonSeriesFolders++;

                        if (nonSeriesFolders >= 3)
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    if (!string.IsNullOrEmpty(EpisodeNumberFromFile(child.Path, false)))
                    {
                        return true;
                    }
                }
            }

            return false;
        }

        public static string EpisodeNumberFromFile(string fullPath, bool isInSeason)
        {
            string fl = fullPath.ToLower();
            foreach (Regex r in episodeExpressions)
            {
                Match m = r.Match(fl);
                if (m.Success)
                    return m.Groups["epnumber"].Value;
            }
            if (isInSeason)
            {
                foreach (Regex r in episodeExpressionsInASeasonFolder)
                {
                    Match m = r.Match(fl);
                    if (m.Success)
                        return m.Groups["epnumber"].Value;
                }

            }

            return null;
        }
    }
}