#pragma warning disable RS0030 // Do not use banned APIs
#pragma warning disable CA1304 // Specify CultureInfo
#pragma warning disable CA1311 // Specify a culture or use an invariant version
#pragma warning disable CA1862 // Use the 'StringComparison' method overloads to perform case-insensitive string comparisons

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Jellyfin.Data.Enums;
using Jellyfin.Database.Implementations;
using Jellyfin.Database.Implementations.Entities;
using Jellyfin.Database.Implementations.Enums;
using Jellyfin.Extensions;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.Querying;
using Microsoft.EntityFrameworkCore;
using BaseItemEntity = Jellyfin.Database.Implementations.Entities.BaseItemEntity;

namespace Jellyfin.Server.Implementations.Item;

public sealed partial class BaseItemRepository
{
    /// <inheritdoc />
    public IQueryable<BaseItemEntity> PrepareItemQuery(JellyfinDbContext context, InternalItemsQuery filter)
    {
        IQueryable<BaseItemEntity> dbQuery = context.BaseItems.AsNoTracking();
        dbQuery = dbQuery.AsSingleQuery();

        return dbQuery;
    }

    private IQueryable<BaseItemEntity> ApplyQueryFilter(IQueryable<BaseItemEntity> dbQuery, JellyfinDbContext context, InternalItemsQuery filter)
    {
        dbQuery = TranslateQuery(dbQuery, context, filter);
        dbQuery = ApplyGroupingFilter(context, dbQuery, filter);
        dbQuery = ApplyQueryPaging(dbQuery, filter);
        dbQuery = ApplyNavigations(dbQuery, filter);
        return dbQuery;
    }

    private IQueryable<BaseItemEntity> ApplyQueryPaging(IQueryable<BaseItemEntity> dbQuery, InternalItemsQuery filter)
    {
        if (filter.Limit.HasValue || filter.StartIndex.HasValue)
        {
            var offset = filter.StartIndex ?? 0;

            if (offset > 0)
            {
                dbQuery = dbQuery.Skip(offset);
            }

            if (filter.Limit.HasValue)
            {
                dbQuery = dbQuery.Take(filter.Limit.Value);
            }
        }

        return dbQuery;
    }

    private IQueryable<BaseItemEntity> ApplyGroupingFilter(JellyfinDbContext context, IQueryable<BaseItemEntity> dbQuery, InternalItemsQuery filter)
    {
        // This whole block is needed to filter duplicate entries on request
        // for the time being it cannot be used because it would destroy the ordering
        // this results in "duplicate" responses for queries that try to lookup individual series or multiple versions but
        // for that case the invoker has to run a DistinctBy(e => e.PresentationUniqueKey) on their own

        var enableGroupByPresentationUniqueKey = EnableGroupByPresentationUniqueKey(filter);
        if (enableGroupByPresentationUniqueKey && filter.GroupBySeriesPresentationUniqueKey)
        {
            var tempQuery = dbQuery.GroupBy(e => new { e.PresentationUniqueKey, e.SeriesPresentationUniqueKey }).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id);
            dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id));
        }
        else if (enableGroupByPresentationUniqueKey)
        {
            var tempQuery = dbQuery.GroupBy(e => e.PresentationUniqueKey).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id);
            dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id));
        }
        else if (filter.GroupBySeriesPresentationUniqueKey)
        {
            var tempQuery = dbQuery.GroupBy(e => e.SeriesPresentationUniqueKey).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id);
            dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id));
        }
        else
        {
            dbQuery = dbQuery.Distinct();
        }

        if (filter.CollapseBoxSetItems == true)
        {
            dbQuery = ApplyBoxSetCollapsing(context, dbQuery, filter.CollapseBoxSetItemTypes);

            // Apply name-range filters after collapse so BoxSets are filtered by their own name,
            // not by their children's names.
            dbQuery = ApplyNameFilters(dbQuery, filter);
        }

        dbQuery = ApplyOrder(dbQuery, filter, context);

        return dbQuery;
    }

    private IQueryable<BaseItemEntity> ApplyBoxSetCollapsing(
        JellyfinDbContext context,
        IQueryable<BaseItemEntity> dbQuery,
        BaseItemKind[] collapsibleTypes)
    {
        var boxSetTypeName = _itemTypeLookup.BaseItemKindNames[BaseItemKind.BoxSet];

        var currentIds = dbQuery.Select(e => e.Id);

        if (collapsibleTypes.Length == 0)
        {
            // Collapse all item types into box sets
            return ApplyBoxSetCollapsingAll(context, currentIds, boxSetTypeName);
        }

        // Only collapse specific item types, keep others untouched
        var collapsibleTypeNames = collapsibleTypes.Select(t => _itemTypeLookup.BaseItemKindNames[t]).ToList();

        // Items whose type is NOT collapsible (always kept in results)
        var nonCollapsibleIds = currentIds
            .Where(id => !context.BaseItems.Any(bi => bi.Id == id && collapsibleTypeNames.Contains(bi.Type)));

        // Collapsible items that are NOT in any box set (kept in results)
        var collapsibleNotInBoxSet = currentIds
            .Where(id =>
                context.BaseItems.Any(bi => bi.Id == id && collapsibleTypeNames.Contains(bi.Type))
                && !context.BaseItems.Any(bs => bs.Id == id && bs.Type == boxSetTypeName)
                && !context.LinkedChildren.Any(lc =>
                    lc.ChildId == id
                    && lc.ChildType == Jellyfin.Database.Implementations.Entities.LinkedChildType.Manual
                    && context.BaseItems.Any(bs => bs.Id == lc.ParentId && bs.Type == boxSetTypeName)));

        // Box set IDs containing at least one accessible collapsible child item
        var boxSetIds = context.LinkedChildren
            .Where(lc =>
                lc.ChildType == Jellyfin.Database.Implementations.Entities.LinkedChildType.Manual
                && currentIds.Contains(lc.ChildId)
                && context.BaseItems.Any(bi => bi.Id == lc.ChildId && collapsibleTypeNames.Contains(bi.Type))
                && context.BaseItems.Any(bs => bs.Id == lc.ParentId && bs.Type == boxSetTypeName))
            .Select(lc => lc.ParentId)
            .Distinct();

        var collapsedIds = nonCollapsibleIds.Union(collapsibleNotInBoxSet).Union(boxSetIds);
        return context.BaseItems.Where(e => collapsedIds.Contains(e.Id));
    }

    private static IQueryable<BaseItemEntity> ApplyBoxSetCollapsingAll(
        JellyfinDbContext context,
        IQueryable<Guid> currentIds,
        string boxSetTypeName)
    {
        // Items that are NOT box sets and NOT in any box set
        var notInBoxSet = currentIds
            .Where(id =>
                !context.BaseItems.Any(bs => bs.Id == id && bs.Type == boxSetTypeName)
                && !context.LinkedChildren.Any(lc =>
                    lc.ChildId == id
                    && lc.ChildType == Jellyfin.Database.Implementations.Entities.LinkedChildType.Manual
                    && context.BaseItems.Any(bs => bs.Id == lc.ParentId && bs.Type == boxSetTypeName)));

        // Box set IDs containing at least one accessible child item
        var boxSetIds = context.LinkedChildren
            .Where(lc =>
                lc.ChildType == Jellyfin.Database.Implementations.Entities.LinkedChildType.Manual
                && currentIds.Contains(lc.ChildId)
                && context.BaseItems.Any(bs => bs.Id == lc.ParentId && bs.Type == boxSetTypeName))
            .Select(lc => lc.ParentId)
            .Distinct();

        var collapsedIds = notInBoxSet.Union(boxSetIds);
        return context.BaseItems.Where(e => collapsedIds.Contains(e.Id));
    }

    private static IQueryable<BaseItemEntity> ApplyNameFilters(IQueryable<BaseItemEntity> dbQuery, InternalItemsQuery filter)
    {
        if (!string.IsNullOrWhiteSpace(filter.NameStartsWith))
        {
            var nameStartsWithLower = filter.NameStartsWith.ToLowerInvariant();
            dbQuery = dbQuery.Where(e => e.SortName!.ToLower().StartsWith(nameStartsWithLower));
        }

        if (!string.IsNullOrWhiteSpace(filter.NameStartsWithOrGreater))
        {
            var startsOrGreaterLower = filter.NameStartsWithOrGreater.ToLowerInvariant();
            dbQuery = dbQuery.Where(e => e.SortName!.ToLower().CompareTo(startsOrGreaterLower) >= 0);
        }

        if (!string.IsNullOrWhiteSpace(filter.NameLessThan))
        {
            var lessThanLower = filter.NameLessThan.ToLowerInvariant();
            dbQuery = dbQuery.Where(e => e.SortName!.ToLower().CompareTo(lessThanLower) < 0);
        }

        return dbQuery;
    }

    /// <inheritdoc />
    public IQueryable<BaseItemEntity> ApplyNavigations(IQueryable<BaseItemEntity> dbQuery, InternalItemsQuery filter)
    {
        if (filter.TrailerTypes.Length > 0 || filter.IncludeItemTypes.Contains(BaseItemKind.Trailer))
        {
            dbQuery = dbQuery.Include(e => e.TrailerTypes);
        }

        if (filter.DtoOptions.ContainsField(ItemFields.ProviderIds))
        {
            dbQuery = dbQuery.Include(e => e.Provider);
        }

        if (filter.DtoOptions.ContainsField(ItemFields.Settings))
        {
            dbQuery = dbQuery.Include(e => e.LockedFields);
        }

        if (filter.DtoOptions.EnableUserData)
        {
            dbQuery = dbQuery.Include(e => e.UserData);
        }

        if (filter.DtoOptions.EnableImages)
        {
            dbQuery = dbQuery.Include(e => e.Images);
        }

        // Include LinkedChildEntities for container types and videos that use them
        // (BoxSet, Playlist, CollectionFolder for manual linking; Video, Movie for alternate versions).
        // When IncludeItemTypes is empty (any type may be returned), always include them to ensure
        // LinkedChildren are loaded before items are saved back, preventing accidental deletion.
        var linkedChildTypes = new[]
        {
            BaseItemKind.BoxSet,
            BaseItemKind.Playlist,
            BaseItemKind.CollectionFolder,
            BaseItemKind.Video,
            BaseItemKind.Movie
        };
        if (filter.IncludeItemTypes.Length == 0 || filter.IncludeItemTypes.Any(linkedChildTypes.Contains))
        {
            dbQuery = dbQuery.Include(e => e.LinkedChildEntities);
        }

        if (filter.IncludeExtras)
        {
            dbQuery = dbQuery.Include(e => e.Extras);
        }

        return dbQuery;
    }

    /// <inheritdoc />
    public IQueryable<BaseItemEntity> ApplyOrder(IQueryable<BaseItemEntity> query, InternalItemsQuery filter, JellyfinDbContext context)
    {
        var orderBy = filter.OrderBy.Where(e => e.OrderBy != ItemSortBy.Default).ToArray();
        var hasSearch = !string.IsNullOrEmpty(filter.SearchTerm);

        // SeriesDatePlayed requires special handling to avoid correlated subqueries.
        // Instead of running a MAX() subquery per-row in ORDER BY, we pre-aggregate
        // max played dates per series in one query and left-join it.
        if (!hasSearch && orderBy.Any(o => o.OrderBy == ItemSortBy.SeriesDatePlayed))
        {
            return ApplySeriesDatePlayedOrder(query, filter, context, orderBy);
        }

        IOrderedQueryable<BaseItemEntity>? orderedQuery = null;

        if (hasSearch)
        {
            var relevanceExpression = OrderMapper.MapSearchRelevanceOrder(filter.SearchTerm!);
            orderedQuery = query.OrderBy(relevanceExpression);
        }

        if (orderBy.Length > 0)
        {
            var firstOrdering = orderBy[0];
            var expression = OrderMapper.MapOrderByField(firstOrdering.OrderBy, filter, context);

            if (orderedQuery is null)
            {
                orderedQuery = firstOrdering.SortOrder == SortOrder.Ascending
                    ? query.OrderBy(expression)
                    : query.OrderByDescending(expression);
            }
            else
            {
                orderedQuery = firstOrdering.SortOrder == SortOrder.Ascending
                    ? orderedQuery.ThenBy(expression)
                    : orderedQuery.ThenByDescending(expression);
            }

            if (firstOrdering.OrderBy is ItemSortBy.Default or ItemSortBy.SortName)
            {
                orderedQuery = firstOrdering.SortOrder == SortOrder.Ascending
                    ? orderedQuery.ThenBy(e => e.Name)
                    : orderedQuery.ThenByDescending(e => e.Name);
            }

            foreach (var item in orderBy.Skip(1))
            {
                expression = OrderMapper.MapOrderByField(item.OrderBy, filter, context);
                orderedQuery = item.SortOrder == SortOrder.Ascending
                    ? orderedQuery.ThenBy(expression)
                    : orderedQuery.ThenByDescending(expression);
            }
        }

        if (orderedQuery is null)
        {
            return query.OrderBy(e => e.SortName);
        }

        // Add SortName as final tiebreaker
        if (!hasSearch && (orderBy.Length == 0 || orderBy.All(o => o.OrderBy is not ItemSortBy.SortName and not ItemSortBy.Name)))
        {
            orderedQuery = orderedQuery.ThenBy(e => e.SortName);
        }

        return orderedQuery;
    }

    private IQueryable<BaseItemEntity> ApplySeriesDatePlayedOrder(
        IQueryable<BaseItemEntity> query,
        InternalItemsQuery filter,
        JellyfinDbContext context,
        (ItemSortBy OrderBy, SortOrder SortOrder)[] orderBy)
    {
        // Pre-aggregate max played date per series key in ONE query.
        // This generates a single: SELECT SeriesPresentationUniqueKey, MAX(LastPlayedDate) ... GROUP BY
        // instead of a correlated subquery per outer row.
        IQueryable<UserData> userDataQuery = filter.User is not null
            ? context.UserData.Where(ud => ud.UserId == filter.User.Id && ud.Played)
            : context.UserData.Where(ud => ud.Played);

        var seriesMaxDates = userDataQuery
            .Join(
                context.BaseItems,
                ud => ud.ItemId,
                bi => bi.Id,
                (ud, bi) => new { bi.SeriesPresentationUniqueKey, ud.LastPlayedDate })
            .Where(x => x.SeriesPresentationUniqueKey != null)
            .GroupBy(x => x.SeriesPresentationUniqueKey)
            .Select(g => new { SeriesKey = g.Key!, MaxDate = g.Max(x => x.LastPlayedDate) });

        var joined = query.LeftJoin(
            seriesMaxDates,
            e => e.PresentationUniqueKey,
            s => s.SeriesKey,
            (e, s) => new { Item = e, MaxDate = s != null ? s.MaxDate : (DateTime?)null });

        var seriesSort = orderBy.First(o => o.OrderBy == ItemSortBy.SeriesDatePlayed);

        return seriesSort.SortOrder == SortOrder.Ascending
            ? joined.OrderBy(x => x.MaxDate).ThenBy(x => x.Item.SortName).Select(x => x.Item)
            : joined.OrderByDescending(x => x.MaxDate).ThenBy(x => x.Item.SortName).Select(x => x.Item);
    }

    /// <summary>
    /// Builds a query for descendants of an ancestor with user access filtering applied.
    /// Uses recursive CTE to traverse both hierarchical (AncestorIds) and linked (LinkedChildren) relationships.
    /// </summary>
    /// <inheritdoc />
    public IQueryable<BaseItemEntity> BuildAccessFilteredDescendantsQuery(
        JellyfinDbContext context,
        InternalItemsQuery filter,
        Guid ancestorId)
    {
        // Use recursive CTE to get all descendants (hierarchical and linked)
        var allDescendantIds = DescendantQueryHelper.GetAllDescendantIds(context, ancestorId);

        var baseQuery = context.BaseItems
            .Where(b => allDescendantIds.Contains(b.Id) && !b.IsFolder && !b.IsVirtualItem);

        return ApplyAccessFiltering(context, baseQuery, filter);
    }

    /// <summary>
    /// Applies user access filtering to a query.
    /// Includes TopParentIds, parental rating, and tag filtering.
    /// </summary>
    /// <inheritdoc />
    public IQueryable<BaseItemEntity> ApplyAccessFiltering(
        JellyfinDbContext context,
        IQueryable<BaseItemEntity> baseQuery,
        InternalItemsQuery filter)
    {
        // Apply TopParentIds filtering (library folder access)
        if (filter.TopParentIds.Length > 0)
        {
            var topParentIds = filter.TopParentIds;
            baseQuery = baseQuery.Where(e => topParentIds.Contains(e.TopParentId!.Value));
        }

        // Apply parental rating filtering
        if (filter.MaxParentalRating is not null)
        {
            baseQuery = baseQuery.Where(BuildMaxParentalRatingFilter(context, filter.MaxParentalRating));
        }

        // Apply block unrated items filtering
        if (filter.BlockUnratedItems.Length > 0)
        {
            var unratedItemTypes = filter.BlockUnratedItems.Select(f => f.ToString()).ToArray();
            baseQuery = baseQuery.Where(e =>
                e.InheritedParentalRatingValue != null || !unratedItemTypes.Contains(e.UnratedType));
        }

        // Apply excluded tags filtering (blocked tags)
        if (filter.ExcludeInheritedTags.Length > 0)
        {
            var excludedTags = filter.ExcludeInheritedTags.Select(e => e.GetCleanValue()).ToArray();
            baseQuery = baseQuery.Where(e =>
                !context.ItemValuesMap.Any(f =>
                    f.ItemValue.Type == ItemValueType.Tags
                    && excludedTags.Contains(f.ItemValue.CleanValue)
                    && (f.ItemId == e.Id
                        || (e.SeriesId.HasValue && f.ItemId == e.SeriesId.Value)
                        || e.Parents!.Any(p => f.ItemId == p.ParentItemId)
                        || (e.TopParentId.HasValue && f.ItemId == e.TopParentId.Value))));
        }

        // Apply included tags filtering (allowed tags - item must have at least one)
        if (filter.IncludeInheritedTags.Length > 0)
        {
            var includeTags = filter.IncludeInheritedTags.Select(e => e.GetCleanValue()).ToArray();
            baseQuery = baseQuery.Where(e =>
                context.ItemValuesMap.Any(f =>
                    f.ItemValue.Type == ItemValueType.Tags
                    && includeTags.Contains(f.ItemValue.CleanValue)
                    && (f.ItemId == e.Id
                        || (e.SeriesId.HasValue && f.ItemId == e.SeriesId.Value)
                        || e.Parents!.Any(p => f.ItemId == p.ParentItemId)
                        || (e.TopParentId.HasValue && f.ItemId == e.TopParentId.Value))));
        }

        return baseQuery;
    }

    /// <summary>
    /// Builds a filter expression for max parental rating that handles both rated items
    /// and unrated BoxSets/Playlists (which check linked children's ratings).
    /// </summary>
    private static Expression<Func<BaseItemEntity, bool>> BuildMaxParentalRatingFilter(
        JellyfinDbContext context,
        ParentalRatingScore maxRating)
    {
        var maxScore = maxRating.Score;
        var maxSubScore = maxRating.SubScore ?? 0;
        var linkedChildren = context.LinkedChildren;

        return e =>
            // Item has a rating: check against limit
            (e.InheritedParentalRatingValue != null
                && (e.InheritedParentalRatingValue < maxScore
                    || (e.InheritedParentalRatingValue == maxScore && (e.InheritedParentalRatingSubValue ?? 0) <= maxSubScore)))
            // Item has no rating
            || (e.InheritedParentalRatingValue == null
                && (
                    // No linked children (not a BoxSet/Playlist): pass as unrated
                    !linkedChildren.Any(lc => lc.ParentId == e.Id)
                    // Has linked children: at least one child must be within limits
                    || linkedChildren.Any(lc => lc.ParentId == e.Id
                        && (lc.Child!.InheritedParentalRatingValue == null
                            || lc.Child.InheritedParentalRatingValue < maxScore
                            || (lc.Child.InheritedParentalRatingValue == maxScore
                                && (lc.Child.InheritedParentalRatingSubValue ?? 0) <= maxSubScore)))));
    }

    private Dictionary<Guid, (int Played, int Total)> GetPlayedAndTotalCountBatch(IReadOnlyList<Guid> folderIds, User user)
    {
        ArgumentNullException.ThrowIfNull(folderIds);
        ArgumentNullException.ThrowIfNull(user);

        if (folderIds.Count == 0)
        {
            return new Dictionary<Guid, (int Played, int Total)>();
        }

        using var dbContext = _dbProvider.CreateDbContext();
        var folderIdsArray = folderIds.ToArray();
        var filter = new InternalItemsQuery(user);
        var userId = user.Id;

        var leafItems = dbContext.BaseItems
            .Where(b => !b.IsFolder && !b.IsVirtualItem);
        leafItems = ApplyAccessFiltering(dbContext, leafItems, filter);

        var playedLeafItems = leafItems
            .Select(b => new { b.Id, Played = b.UserData!.Any(ud => ud.UserId == userId && ud.Played) });

        var ancestorLeaves = dbContext.AncestorIds
            .WhereOneOrMany(folderIdsArray, a => a.ParentItemId)
            .Join(
                playedLeafItems,
                a => a.ItemId,
                b => b.Id,
                (a, b) => new { FolderId = a.ParentItemId, b.Id, b.Played });

        var linkedLeaves = dbContext.LinkedChildren
            .WhereOneOrMany(folderIdsArray, lc => lc.ParentId)
            .Join(
                playedLeafItems,
                lc => lc.ChildId,
                b => b.Id,
                (lc, b) => new { FolderId = lc.ParentId, b.Id, b.Played });

        var linkedFolderLeaves = dbContext.LinkedChildren
            .WhereOneOrMany(folderIdsArray, lc => lc.ParentId)
            .Join(
                dbContext.BaseItems.Where(b => b.IsFolder),
                lc => lc.ChildId,
                b => b.Id,
                (lc, b) => new { lc.ParentId, FolderChildId = b.Id })
            .Join(
                dbContext.AncestorIds,
                x => x.FolderChildId,
                a => a.ParentItemId,
                (x, a) => new { x.ParentId, DescendantId = a.ItemId })
            .Join(
                playedLeafItems,
                x => x.DescendantId,
                b => b.Id,
                (x, b) => new { FolderId = x.ParentId, b.Id, b.Played });

        var results = ancestorLeaves
            .Union(linkedLeaves)
            .Union(linkedFolderLeaves)
            .GroupBy(x => x.FolderId)
            .Select(g => new
            {
                FolderId = g.Key,
                Total = g.Select(x => x.Id).Distinct().Count(),
                Played = g.Where(x => x.Played).Select(x => x.Id).Distinct().Count()
            })
            .ToDictionary(x => x.FolderId, x => (x.Played, x.Total));

        return results;
    }
}