using Microsoft.EntityFrameworkCore;
using RadicadeServer.API.Storefront;
using RadicadeServer.DB;
using RadicadeServer.Extensions;
using RadicadeServer.RecNet.Avatar;
using RadicadeServer.RecNet.Enums.Store;
using RadicadeServer.RecNet.Progression;

namespace RadicadeServer.Utils
{
    public static class GameRewardRedemption
    {
        public static async Task<Gift?> TakeOutstandingAsync(
            RecDBContext db, long playerId, GiftContext context, string? message = null, Action<string>? trace = null)
        {
            var data = await db.Progression.FirstOrDefaultAsync(x => x.PlayerId == playerId);
            var json = data?.GetProgressionJson();
            var pending = json?.PendingGameRewards;

            var outstanding = pending?.Where(r => !r.Consumed).ToList() ?? new List<RecNet.Storefront.GameReward>();
            trace?.Invoke($"stage=OutstandingReward claimed={RewardTrace.Context(context)} " +
                $"rewards={pending?.Count ?? 0} outstanding={outstanding.Count}");

            if (data == null || json == null || outstanding.Count == 0) return null;

            foreach (var candidate in outstanding)
            {
                var held = candidate.GiftDrop1 ?? candidate.GiftDrop2 ?? candidate.GiftDrop3;
                trace?.Invoke($"stage=OutstandingCandidate selectionId={candidate.RewardSelectionId} " +
                    $"rewardType={candidate.RewardType} context={RewardTrace.Context(candidate.GiftContext)} " +
                    $"box={RewardTrace.Box(held)}");
            }

            var reward = outstanding.FirstOrDefault(r => r.GiftContext == context);
            var matchedBy = reward == null ? null : "context";

            if (reward == null && RroRewardPools.RoomForContext(context) is { } room)
            {
                reward = outstanding.FirstOrDefault(r => RroRewardPools.RoomForContext(r.GiftContext) == room);
                matchedBy = reward == null ? null : $"room={room}";
            }

            if (reward == null)
            {
                reward = outstanding[0];
                matchedBy = "oldest outstanding";
            }

            var drop = reward.GiftDrop1 ?? reward.GiftDrop2 ?? reward.GiftDrop3;
            if (drop == null)
            {
                trace?.Invoke($"stage=OutstandingRewardUnusable selectionId={reward.RewardSelectionId} " +
                    "has no gift drop at all; nothing can be handed over from it.");
                return null;
            }

            var gift = drop.Clone();
            if (!string.IsNullOrWhiteSpace(message)) gift.Tooltip = message;
            if (gift.GiftDropId == 0) gift.GiftDropId = StorefrontShared.NewGiftDropId();

            reward.Consumed = true;
            reward.ConsumedGiftDropId = gift.GiftDropId;
            reward.ConsumedAt = DateTime.UtcNow;

            data.Progress = json.ToJson();
            await db.SaveChangesAsync();

            trace?.Invoke($"stage=OutstandingRewardMatched by={matchedBy} selectionId={reward.RewardSelectionId} " +
                $"rewardType={reward.RewardType} context={RewardTrace.Context(reward.GiftContext)} " +
                $"box={RewardTrace.Box(gift)}");

            return gift;
        }

        public static async Task<Gift?> BuildRoomRewardAsync(
            RecDBContext db, long playerId, GiftContext context, string? message = null,
            Action<string>? trace = null, string? catalogueJson = null)
        {
            var room = RroRewardPools.RoomForContext(context);
            if (room == null) return null;

            var owned = await LevelUpGiftService.CollectOwnedKeysAsync(db, playerId, context);

            Gift? box = RroRewardPools.BuildGift(context, owned, catalogueJson: catalogueJson);
            var paidFrom = context;

            if (box == null)
            {
                foreach (var weaker in RroRewardPools.LowerRanksOf(context))
                {
                    box = RroRewardPools.BuildGift(weaker, owned, catalogueJson: catalogueJson);
                    if (box == null) continue;

                    paidFrom = weaker;
                    trace?.Invoke($"stage=RoomBoxFallbackRank context={RewardTrace.Context(context)} " +
                        $"nothing left unowned, so the same quest's {RewardTrace.Context(weaker)} is what it pays.");
                    break;
                }
            }

            if (box == null)
            {
                box = RroRewardPools.BuildFallbackDrops(selection: false, owned: owned).FirstOrDefault();
                if (box != null)
                {
                    paidFrom = RroRewardPools.ReacquisitionContext;
                    trace?.Invoke($"stage=RoomBoxFallbackItem context={RewardTrace.Context(context)} " +
                        "every reward the activity pays is owned; paying the non-exclusive item pool.");
                }
            }

            if (box == null) return null;

            box.GiftDropId = StorefrontShared.NewGiftDropId();
            if (!string.IsNullOrWhiteSpace(message)) box.Tooltip = message;

            trace?.Invoke($"stage=RoomBox activity={room} context={RewardTrace.Context(context)} " +
                $"paidFrom={RewardTrace.Context(paidFrom)} box={RewardTrace.Box(box)}");

            await RememberHandoverAsync(db, playerId, context, box, trace);
            return box;
        }

        public static async Task RememberHandoverAsync(
            RecDBContext db, long playerId, GiftContext context, Gift box, Action<string>? trace = null)
        {
            var data = await db.Progression.FirstOrDefaultAsync(x => x.PlayerId == playerId);
            if (data == null)
            {
                data = new ProgressionData { PlayerId = playerId };
                db.Progression.Add(data);
            }

            var json = data.GetProgressionJson() ?? new ProgressionJson();
            json.PendingGameRewards ??= new List<RecNet.Storefront.GameReward>();
            json.PendingGameRewards.Add(new RecNet.Storefront.GameReward
            {
                RewardSelectionId = StorefrontShared.NewGiftDropId(),
                Message = box.Tooltip ?? string.Empty,
                GiftContext = context,
                RewardType = RroRewardPools.IsQuestContext(context)
                    ? RewardType.PostQuestActivity
                    : RewardType.PostGameActivity,
                GiftDrop1 = box.Clone(),
                CreatedAt = DateTime.UtcNow,
                Consumed = true,
                ConsumedGiftDropId = box.GiftDropId,
                ConsumedAt = DateTime.UtcNow
            });

            data.Progress = json.ToJson();
            await db.SaveChangesAsync();

            trace?.Invoke($"stage=HandoverRecorded context={RewardTrace.Context(context)} " +
                $"box={RewardTrace.Box(box)} the completion is recorded as delivered, so a later request " +
                "for it cannot pay a second box.");
        }

        public static async Task<Gift?> TakePendingBoxAsync(
            RecDBContext db, long playerId, GiftContext context, Action<string>? trace = null)
        {
            var room = RroRewardPools.RoomForContext(context);
            if (room == null || !RroRewardPools.IsRewardActivity(room)) return null;

            var boxes = await StorefrontShared.GetPendingGiftsAsync(db, playerId);
            var box = boxes.FirstOrDefault(b => b.Context == context)
                ?? boxes.FirstOrDefault(b => RroRewardPools.RoomForContext(b.Context) == room);

            trace?.Invoke($"stage=PendingBox claimed={RewardTrace.Context(context)} room={room} " +
                $"held={boxes.Count} match={RewardTrace.Box(box)}");

            if (box == null) return null;

            var gift = box.Clone();
            if (gift.GiftDropId == 0) gift.GiftDropId = StorefrontShared.NewGiftDropId();
            return gift;
        }

        public static async Task<Gift?> TakeRecentlyHandedOverAsync(
            RecDBContext db, long playerId, GiftContext context, TimeSpan within, Action<string>? trace = null)
        {
            var data = await db.Progression.FirstOrDefaultAsync(x => x.PlayerId == playerId);
            var json = data?.GetProgressionJson();
            var pending = json?.PendingGameRewards;
            if (pending == null || pending.Count == 0) return null;

            var cutoff = DateTime.UtcNow - within;
            var taken = pending
                .Where(r => r.Consumed && r.ConsumedAt is { } at && at >= cutoff)
                .Where(r => r.GiftContext == context
                    || (RroRewardPools.RoomForContext(context) is { } room
                        && RroRewardPools.RoomForContext(r.GiftContext) == room))
                .OrderByDescending(r => r.ConsumedAt)
                .FirstOrDefault();

            if (taken == null)
            {
                trace?.Invoke($"stage=HandedOver claimed={RewardTrace.Context(context)} none within {within}.");
                return null;
            }

            var drop = taken.GiftDrop1 ?? taken.GiftDrop2 ?? taken.GiftDrop3;
            if (drop == null) return null;

            var gift = drop.Clone();
            gift.GiftDropId = taken.ConsumedGiftDropId != 0 ? taken.ConsumedGiftDropId : gift.GiftDropId;
            trace?.Invoke($"stage=HandedOver claimed={RewardTrace.Context(context)} " +
                $"selectionId={taken.RewardSelectionId} box={RewardTrace.Box(gift)} - answering the retry " +
                "with the box it was given.");
            return gift;
        }
    }
}