using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;
using SharedKernel.Storage;
using Domain.Entities.Store;

namespace Application.Features.Admin.Store.Game.Update;

public sealed class Handler(IAppDbContext db, IFileStorage fileStorage) : ICommandHandler<Command, Result>
{
    private static readonly string[] AllowedImageExt = [".jpg", ".jpeg", ".png", ".gif", ".webp"];

    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        if (request.CommissionRate < 0 || request.CommissionRate > 100)
        {
            return Result.Failure(Error.Problem("Game.InvalidCommissionRate", "게임사 수익률은 0~100% 사이여야 합니다."));
        }

        var game = await db.Game.FirstOrDefaultAsync(c => c.ID == request.ID, ct);

        if (game is null)
        {
            return Result.Failure(Error.NotFound("Game.NotFound", "게임을 찾을 수 없습니다."));
        }

        var code = NormalizeOptional(request.Code);
        var engName = NormalizeOptional(request.EngName);
        var link = NormalizeOptional(request.Link);

        // 한글명 중복 (본인 제외)
        if (await db.Game.AnyAsync(c => c.ID != request.ID && c.KorName == request.KorName, ct))
        {
            return Result.Failure(Error.Conflict("Game.DuplicateKorName", "이미 같은 한글명의 게임이 등록되어 있습니다."));
        }

        // 게임 코드 중복 (본인 제외, 입력 시에만)
        if (code is not null && await db.Game.AnyAsync(c => c.ID != request.ID && c.Code == code, ct))
        {
            return Result.Failure(Error.Conflict("Game.DuplicateCode", "이미 같은 코드의 게임이 등록되어 있습니다."));
        }

        // 작은 이미지 처리
        string? newThumbnail = game.Thumbnail;

        if (request.RemoveThumbnail)
        {
            newThumbnail = null;
        }

        if (request.ThumbnailFile is not null)
        {
            var uploadPath = new FileStoragePath(UploadTarget.Upload, UploadFolder.StoreGame, game.ID);
            var saved = await fileStorage.SaveFileAsync(request.ThumbnailFile, uploadPath, AllowedImageExt, ct);

            if (saved is not null)
            {
                newThumbnail = saved.Url;
            }
        }

        // 큰 이미지 처리
        string? newBigImage = game.BigImage;

        if (request.RemoveBigImage)
        {
            newBigImage = null;
        }

        if (request.BigImageFile is not null)
        {
            var uploadPath = new FileStoragePath(UploadTarget.Upload, UploadFolder.StoreGame, game.ID);
            var saved = await fileStorage.SaveFileAsync(request.BigImageFile, uploadPath, AllowedImageExt, ct);

            if (saved is not null)
            {
                newBigImage = saved.Url;
            }
        }

        game.Update(
            korName: request.KorName,
            publisher: request.Publisher,
            commissionRate: request.CommissionRate,
            code: code,
            engName: engName,
            thumbnail: newThumbnail,
            bigImage: newBigImage,
            description: request.Description,
            link: link,
            order: request.Order,
            isActive: request.IsActive
        );

        if (request.ApiCommissionRate < 0 || request.ApiCommissionRate > 100)
        {
            return Result.Failure(Error.Problem("Game.InvalidApiCommissionRate", "API 수수료율은 0~100% 사이여야 합니다."));
        }

        game.SetApiCommissionRate(request.ApiCommissionRate);
        game.SetDetail(request.TrailerUrl, request.MinSpec, request.RecommendedSpec, request.ReleaseDate);

        var urlsToDelete = await SyncDetailAsync(game.ID, request, ct);

        await db.SaveChangesAsync(ct);

        // 물리 파일 삭제는 DB 커밋 성공 후에만 (실패 시 고아 파일/행 방지)
        foreach (var url in urlsToDelete)
        {
            fileStorage.DeleteByUrl(url);
        }

        return Result.Success();
    }

    private async Task<List<string>> SyncDetailAsync(int gameID, Command request, CancellationToken ct)
    {
        var urlsToDelete = new List<string>();

        // 장르 맵 재동기화 (선택분과 비교해 추가/삭제만 — 복합키 재추가 식별자 충돌 방지)
        var existingGenres = await db.GameGenreMap.Where(m => m.GameID == gameID).ToListAsync(ct);
        var selectedGenreIds = request.GenreIDs is { Count: > 0 } genreIds
            ? (await db.GameGenre.Where(g => genreIds.Contains(g.ID)).Select(g => g.ID).ToListAsync(ct)).ToHashSet()
            : new HashSet<int>();
        var existingGenreIds = existingGenres.Select(m => m.GameGenreID).ToHashSet();

        foreach (var m in existingGenres)
        {
            if (!selectedGenreIds.Contains(m.GameGenreID))
            {
                db.GameGenreMap.Remove(m);
            }
        }
        foreach (var id in selectedGenreIds)
        {
            if (!existingGenreIds.Contains(id))
            {
                db.GameGenreMap.Add(GameGenreMap.Create(gameID, id));
            }
        }

        // 카테고리 맵 재동기화 (동일 패턴)
        var existingCategories = await db.GameCategoryMap.Where(m => m.GameID == gameID).ToListAsync(ct);
        var selectedCategoryIds = request.CategoryIDs is { Count: > 0 } categoryIds
            ? (await db.GameCategory.Where(c => categoryIds.Contains(c.ID)).Select(c => c.ID).ToListAsync(ct)).ToHashSet()
            : new HashSet<int>();
        var existingCategoryIds = existingCategories.Select(m => m.GameCategoryID).ToHashSet();

        foreach (var m in existingCategories)
        {
            if (!selectedCategoryIds.Contains(m.GameCategoryID))
            {
                db.GameCategoryMap.Remove(m);
            }
        }
        foreach (var id in selectedCategoryIds)
        {
            if (!existingCategoryIds.Contains(id))
            {
                db.GameCategoryMap.Add(GameCategoryMap.Create(gameID, id));
            }
        }

        // 기존 이미지 삭제 (물리 파일은 커밋 후 삭제하도록 URL 수집)
        if (request.RemoveImageIDs is { Count: > 0 } removeIds)
        {
            var toRemove = await db.GameImage.Where(i => i.GameID == gameID && removeIds.Contains(i.ID)).ToListAsync(ct);
            foreach (var img in toRemove)
            {
                urlsToDelete.Add(img.Url);
            }
            db.GameImage.RemoveRange(toRemove);
        }

        // 기존 이미지 순서 재지정 (드래그 정렬)
        var nextOrder = 0;
        if (request.ImageOrder is { Count: > 0 } orderIds)
        {
            var imgs = await db.GameImage.Where(i => i.GameID == gameID && orderIds.Contains(i.ID)).ToListAsync(ct);
            var byId = imgs.ToDictionary(i => i.ID);
            var pos = 0;
            foreach (var id in orderIds)
            {
                if (byId.TryGetValue(id, out var img))
                {
                    img.Order = pos++;
                }
            }
            nextOrder = pos;
        }
        else
        {
            nextOrder = (await db.GameImage.Where(i => i.GameID == gameID).Select(i => (int?)i.Order).MaxAsync(ct) ?? -1) + 1;
        }

        // 신규 이미지 업로드 (재지정된 순서 뒤에 추가)
        if (request.DetailImages is { Count: > 0 })
        {
            var uploadPath = new FileStoragePath(UploadTarget.Upload, UploadFolder.StoreGameDetail, gameID);
            var order = nextOrder;

            foreach (var image in request.DetailImages)
            {
                var saved = await fileStorage.SaveFileAsync(image, uploadPath, AllowedImageExt, ct);
                if (saved is null)
                {
                    continue;
                }

                db.GameImage.Add(new GameImage
                {
                    GameID = gameID,
                    FileName = image.FileName,
                    HashedName = saved.FileName,
                    Path = uploadPath.ToRelativePath(),
                    Url = saved.Url,
                    Extension = saved.Extension,
                    ContentType = image.ContentType,
                    Size = saved.Size,
                    Width = saved.Width,
                    Height = saved.Height,
                    Order = order++
                });
            }
        }

        // 언어 지원 재동기화 (기존과 비교: 추가/수정/삭제. 활성 언어만, 중복 ID 정리, 셋 다 미체크면 미저장)
        var existingLangs = await db.GameLanguageSupport.Where(s => s.GameID == gameID).ToListAsync(ct);
        var existingByLangId = existingLangs.ToDictionary(s => s.GameLanguageID);

        var submitted = new Dictionary<int, Command.LanguageRow>();
        if (request.Languages is { Count: > 0 } langs)
        {
            var reqIds = langs.Select(x => x.GameLanguageID).ToList();
            var validIds = (await db.GameLanguage.Where(l => reqIds.Contains(l.ID) && l.IsActive).Select(l => l.ID).ToListAsync(ct)).ToHashSet();

            foreach (var row in langs)
            {
                if (!validIds.Contains(row.GameLanguageID))
                {
                    continue;
                }
                if (!row.Interface && !row.FullAudio && !row.Subtitles)
                {
                    continue;
                }
                submitted[row.GameLanguageID] = row;
            }
        }

        foreach (var s in existingLangs)
        {
            if (!submitted.ContainsKey(s.GameLanguageID))
            {
                db.GameLanguageSupport.Remove(s);
            }
        }
        foreach (var (langId, row) in submitted)
        {
            if (existingByLangId.TryGetValue(langId, out var existing))
            {
                existing.SetSupport(row.Interface, row.FullAudio, row.Subtitles);
            }
            else
            {
                db.GameLanguageSupport.Add(GameLanguageSupport.Create(gameID, langId, row.Interface, row.FullAudio, row.Subtitles));
            }
        }

        return urlsToDelete;
    }

    private static string? NormalizeOptional(string? value)
    {
        return string.IsNullOrWhiteSpace(value) ? null : value.Trim();
    }
}