using EmbyToolbox.Models;

namespace EmbyToolbox.Services;

public sealed class BulkTrackSettingsService
{
    private readonly TrackStructureComparer _comparer = new();

    public BulkTrackSelectionAnalysis Analyze(IReadOnlyList<ConversionQueueItem> selected)
    {
        var candidates = selected
            .Where(i => i.MediaAnalysis is not null && i.TaskOverride.TrackOverrides.Count > 0)
            .ToList();

        if (candidates.Count < 2)
        {
            return BulkTrackSelectionAnalysis.Empty;
        }

        var groups = candidates
            .GroupBy(i => _comparer.BuildSignature(i.TaskOverride.TrackOverrides))
            .Select(g => new { Signature = g.Key, Items = g.OrderBy(i => i.OrderNumber).ToList() })
            .OrderByDescending(g => g.Items.Count)
            .ThenBy(g => g.Items[0].OrderNumber)
            .ToList();

        if (groups.Count == 0)
        {
            return BulkTrackSelectionAnalysis.Empty;
        }

        var top = groups[0];
        if (groups.Count > 1 && groups[1].Items.Count == top.Items.Count)
        {
            return new BulkTrackSelectionAnalysis(null, [], candidates.OrderBy(i => i.OrderNumber).ToList(), false);
        }

        var skipped = candidates.Except(top.Items).OrderBy(i => i.OrderNumber).ToList();
        return new BulkTrackSelectionAnalysis(top.Signature, top.Items, skipped, true);
    }

    public void ApplyBulkEdits(
        IReadOnlyList<ConversionQueueItem> targets,
        IReadOnlyList<TrackOverrideEntry> editedTemplateTracks)
    {
        foreach (var item in targets)
        {
            if (item.TaskOverride.TrackOverrides.Count != editedTemplateTracks.Count)
            {
                continue;
            }

            for (var i = 0; i < editedTemplateTracks.Count; i++)
            {
                var dst = item.TaskOverride.TrackOverrides[i];
                var src = editedTemplateTracks[i];
                dst.Action = src.Action;
                dst.AudioBitrateKbps = src.AudioBitrateKbps;
                dst.Default = src.Default;
                dst.Language = src.Language;
                dst.Title = src.Title;
            }
        }
    }
}

public sealed record BulkTrackSelectionAnalysis(
    string? MajoritySignature,
    IReadOnlyList<ConversionQueueItem> MajorityItems,
    IReadOnlyList<ConversionQueueItem> SkippedItems,
    bool HasMajority)
{
    public static BulkTrackSelectionAnalysis Empty { get; } = new(null, [], [], false);
}