using System;
using System.Collections.Generic;
using System.Globalization;

namespace Jellyfin.Plugin.RecentlyAddedGuard.Core;

/// <summary>
/// Builds the alias keys that identify a logical medium independent of its file path.
/// </summary>
/// <remarks>
/// Keys are compared case-insensitively by the ledger, so provider ids are only trimmed.
/// </remarks>
public static class MediaKeys
{
    /// <summary>
    /// Builds the keys of a movie from its provider ids.
    /// </summary>
    /// <param name="tmdbId">The TMDb id, if known.</param>
    /// <param name="imdbId">The IMDb id, if known.</param>
    /// <param name="tvdbId">The TVDb id, if known.</param>
    /// <returns>The keys; empty if the movie has no provider id yet.</returns>
    public static IReadOnlyList<string> ForMovie(string? tmdbId, string? imdbId, string? tvdbId)
    {
        var keys = new List<string>(3);
        AddIfPresent(keys, "movie:tmdb:", tmdbId, string.Empty);
        AddIfPresent(keys, "movie:imdb:", imdbId, string.Empty);
        AddIfPresent(keys, "movie:tvdb:", tvdbId, string.Empty);
        return keys;
    }

    /// <summary>
    /// Builds the episode part of an episode key, e.g. <c>s1e5</c> or <c>s1e5-6</c> for a double episode.
    /// </summary>
    /// <param name="seasonNumber">The season number (<c>ParentIndexNumber</c>).</param>
    /// <param name="episodeNumber">The episode number (<c>IndexNumber</c>).</param>
    /// <param name="episodeNumberEnd">The last episode number of a multi-episode file (<c>IndexNumberEnd</c>).</param>
    /// <returns>The episode part, or <c>null</c> if season or episode number is missing.</returns>
    public static string? EpisodePart(int? seasonNumber, int? episodeNumber, int? episodeNumberEnd)
    {
        if (seasonNumber is not { } season || episodeNumber is not { } episode)
        {
            return null;
        }

        return episodeNumberEnd is { } end && end > episode
            ? string.Create(CultureInfo.InvariantCulture, $"s{season}e{episode}-{end}")
            : string.Create(CultureInfo.InvariantCulture, $"s{season}e{episode}");
    }

    /// <summary>
    /// Builds the keys of an episode.
    /// </summary>
    /// <param name="episodePart">The episode part from <see cref="EpisodePart"/>.</param>
    /// <param name="seriesTvdbId">The series' TVDb id, if known.</param>
    /// <param name="seriesTmdbId">The series' TMDb id, if known.</param>
    /// <param name="seriesImdbId">The series' IMDb id, if known.</param>
    /// <param name="seriesId">The Jellyfin id of the series; <see cref="Guid.Empty"/> if unknown.</param>
    /// <returns>The keys; contains the series-guid key whenever the series id is known.</returns>
    public static IReadOnlyList<string> ForEpisode(
        string episodePart,
        string? seriesTvdbId,
        string? seriesTmdbId,
        string? seriesImdbId,
        Guid seriesId)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(episodePart);

        var suffix = ":" + episodePart;
        var keys = new List<string>(4);
        AddIfPresent(keys, "ep:tvdb:", seriesTvdbId, suffix);
        AddIfPresent(keys, "ep:tmdb:", seriesTmdbId, suffix);
        AddIfPresent(keys, "ep:imdb:", seriesImdbId, suffix);
        if (seriesId != Guid.Empty)
        {
            keys.Add("ep:series-guid:" + seriesId.ToString("N", CultureInfo.InvariantCulture) + suffix);
        }

        return keys;
    }

    private static void AddIfPresent(List<string> keys, string prefix, string? id, string suffix)
    {
        if (!string.IsNullOrWhiteSpace(id))
        {
            keys.Add(prefix + id.Trim() + suffix);
        }
    }
}