using LiteDB;

namespace Campus_live_rewrite.api.dbs
{
    /// <summary>
    /// Item wishlists (POST /api/itemWishlists/v1/wishlist/add|remove). The client's add 405'd
    /// (only the reads existed); the row is recorded here so the add answers and the panel can
    /// read it back. The wishlist DTO the client renders is not pinned yet, so the reads stay
    /// empty until it is (see the wishlist routes) - nothing is lost, the rows are here.
    /// </summary>
    public static class WishlistDB
    {
        private static readonly Lazy<LiteDatabase> _db = new(() => new LiteDatabase(Path.Combine("Data", "DBs", "Wishlists.db")));

        public class Row
        {
            [BsonId] public string Key { get; set; } = "";   // "{account}|{storefront}|{item}"
            public ulong AccountId { get; set; }
            public int StorefrontType { get; set; }
            public int PurchasableItemId { get; set; }
            // A UGC (custom avatar item) wish: PurchasableItemId is -1 and this is the item's GUID.
            public string? CustomAvatarItemId { get; set; }
            public string RawBody { get; set; } = "";
            public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
        }

        private static ILiteCollection<Row> Col()
        {
            var c = _db.Value.GetCollection<Row>("items");
            c.EnsureIndex(x => x.AccountId);
            return c;
        }

        private static string KeyFor(ulong account, int item, string? custom) =>
            string.IsNullOrWhiteSpace(custom) ? $"{account}|{item}" : $"{account}|ugc|{custom.ToLowerInvariant()}";

        /// <summary>Record a wish; returns the row (existing or new) so the add can answer it.</summary>
        public static Row Add(ulong account, int storefront, int item, string? custom, string raw)
        {
            var key = KeyFor(account, item, custom);
            try
            {
                var existing = Col().FindById(key);
                if (existing != null) return existing;
                var row = new Row { Key = key, AccountId = account, StorefrontType = storefront, PurchasableItemId = item, CustomAvatarItemId = string.IsNullOrWhiteSpace(custom) ? null : custom, RawBody = raw };
                Col().Upsert(row);
                return row;
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[wishlist] add failed: {ex.Message}");
                return new Row { Key = key, AccountId = account, StorefrontType = storefront, PurchasableItemId = item, CustomAvatarItemId = custom };
            }
        }

        public static void Remove(ulong account, int item, string? custom = null)
        {
            try
            {
                if (!string.IsNullOrWhiteSpace(custom))
                {
                    string c = custom.ToLowerInvariant();
                    Col().DeleteMany(x => x.AccountId == account && x.CustomAvatarItemId != null && x.CustomAvatarItemId.ToLower() == c);
                }
                else Col().DeleteMany(x => x.AccountId == account && x.PurchasableItemId == item && x.CustomAvatarItemId == null);
            }
            catch (Exception ex) { Console.WriteLine($"[wishlist] remove failed: {ex.Message}"); }
        }

        /// <summary>The wire entry (real RecNet: WishlistItemId guid, AccountId, PurchasableItemId, CreatedAt;
        /// the 2025 client adds CustomAvatarItemId for UGC wishes). The guid is derived from the key so it is stable.</summary>
        public static Guid WireId(Row r)
        {
            using var md5 = System.Security.Cryptography.MD5.Create();
            return new Guid(md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes("wish|" + r.Key)));
        }

        public static object ToWire(Row r)
        {
            Guid id = WireId(r);
            return new
            {
                WishlistItemId = id,
                AccountId = r.AccountId,
                PurchasableItemId = r.PurchasableItemId,
                CustomAvatarItemId = r.CustomAvatarItemId,
                CreatedAt = r.CreatedAt
            };
        }
        public static List<object> WireFor(ulong account) => For(account).Select(ToWire).ToList();

        public static List<Row> For(ulong account) => Col().Find(x => x.AccountId == account).OrderBy(x => x.CreatedAt).ToList();
    }
}