using System.Collections.Generic;
using System.IO;
using System.Linq;
using NLog;
using NzbDrone.Common.Extensions;
using NzbDrone.Core.Profiles.Releases;
using NzbDrone.Core.Tv;

namespace NzbDrone.Core.MediaFiles
{
    public interface IEpisodeFilePreferredWordCalculator
    {
        int Calculate(Series series, EpisodeFile episodeFile);
    }

    public class EpisodeFilePreferredWordCalculator : IEpisodeFilePreferredWordCalculator
    {
        private readonly IPreferredWordService _preferredWordService;
        private readonly Logger _logger;

        public EpisodeFilePreferredWordCalculator(IPreferredWordService preferredWordService, Logger logger)
        {
            _preferredWordService = preferredWordService;
            _logger = logger;
        }

        public int Calculate(Series series, EpisodeFile episodeFile)
        {
            var scores = new List<int>();

            if (episodeFile.SceneName.IsNotNullOrWhiteSpace())
            {
                AddScoreIfApplicable(series, episodeFile.SceneName, scores);
            }
            else
            {
                _logger.Trace("No stored scene name for {0}", episodeFile);
            }

            // The file may not have a screen name if the file/folder name contained spaces, but the original path is still store and valuable.
            if (episodeFile.OriginalFilePath.IsNotNullOrWhiteSpace())
            {
                var segments = episodeFile.OriginalFilePath.Split(Path.DirectorySeparatorChar).ToList();

                for (int i = 0; i < segments.Count; i++)
                {
                    var isLast = i == segments.Count - 1;
                    var segment = isLast ? Path.GetFileNameWithoutExtension(segments[i]) : segments[i];

                    AddScoreIfApplicable(series, segment, scores);
                }
            }
            else
            {
                _logger.Trace("No stored scene name for {0}", episodeFile);
            }

            // Calculate using RelativePath or Path, but not both
            if (episodeFile.RelativePath.IsNotNullOrWhiteSpace())
            {
                AddScoreIfApplicable(series, episodeFile.RelativePath, scores);
            }
            else if (episodeFile.Path.IsNotNullOrWhiteSpace())
            {
                AddScoreIfApplicable(series, episodeFile.Path, scores);
            }

            // Return the highest score, this will allow media info in file names to be used to improve preferred word scoring.
            // TODO: A full map of preferred words should be de-duped and used to create an aggregated score using the scene name and the file name.

            return scores.MaxOrDefault();
        }

        private void AddScoreIfApplicable(Series series, string title, List<int> scores)
        {
            var score = 0;
            _logger.Trace("Calculating preferred word score for '{0}'", title);

            var matchingPairs = _preferredWordService.GetMatchingPreferredWordsAndScores(series, title, 0);

            // Only add the score if there are matching terms 
            if (matchingPairs.Any())
            {
                score = matchingPairs.Sum(p => p.Value);
                scores.Add(score);
            }

            _logger.Trace("Calculated preferred word score for '{0}': {1} ({2} match(es))", title, score, matchingPairs.Count);
        }
    }
}