#nullable disable
using NadekoBot.Services.Database;
using NadekoBot.Services.Database.Models;
using NadekoBot.Db;
using NadekoBot.Modules.Gambling.Services;

namespace NadekoBot.Services;

public class CurrencyService : ICurrencyService, INService
{
    private readonly DbService _db;
    private readonly GamblingConfigService _gss;
    private readonly IEmbedBuilderService _eb;
    private readonly IUser _bot;

    public CurrencyService(DbService db, DiscordSocketClient c, GamblingConfigService gss, IEmbedBuilderService eb)
    {
        _db = db;
        _gss = gss;
        _eb = eb;
        _bot = c.CurrentUser;
    }

    private CurrencyTransaction GetCurrencyTransaction(ulong userId, string reason, long amount) =>
        new()
        {
            Amount = amount,
            UserId = userId,
            Reason = reason ?? "-",
        };

    private bool InternalChange(ulong userId, string userName, string discrim, string avatar,
        string reason, long amount, bool gamble, NadekoContext uow)
    {
        var result = uow.TryUpdateCurrencyState(userId, userName, discrim, avatar, amount);
        if (result)
        {
            var t = GetCurrencyTransaction(userId, reason, amount);
            uow.CurrencyTransactions.Add(t);

            if (gamble)
            {
                var t2 = GetCurrencyTransaction(_bot.Id, reason, -amount);
                uow.CurrencyTransactions.Add(t2);
                uow.TryUpdateCurrencyState(_bot.Id, _bot.Username, _bot.Discriminator, _bot.AvatarId, -amount, true);
            }
        }
        return result;
    }

    private async Task InternalAddAsync(ulong userId, string userName, string discrim, string avatar, string reason, long amount, bool gamble)
    {
        if (amount < 0)
        {
            throw new ArgumentException("You can't add negative amounts. Use RemoveAsync method for that.", nameof(amount));
        }

        await using var uow = _db.GetDbContext();
        InternalChange(userId, userName, discrim, avatar, reason, amount, gamble, uow);
        await uow.SaveChangesAsync();
    }

    public Task AddAsync(ulong userId, string reason, long amount, bool gamble = false)
        => InternalAddAsync(userId, null, null, null, reason, amount, gamble);

    public async Task AddAsync(IUser user, string reason, long amount, bool sendMessage = false, bool gamble = false)
    {
        await InternalAddAsync(user.Id, user.Username, user.Discriminator, user.AvatarId, reason, amount, gamble);
        if (sendMessage)
        {
            try
            {
                var sign = _gss.Data.Currency.Sign;
                await user
                    .EmbedAsync(_eb.Create()
                        .WithOkColor()
                        .WithTitle($"Received Currency")
                        .AddField("Amount", amount + sign)
                        .AddField("Reason", reason));
            }
            catch
            {
                // ignored
            }
        }
    }

    public async Task AddBulkAsync(IEnumerable<ulong> userIds, IEnumerable<string> reasons, IEnumerable<long> amounts, bool gamble = false)
    {
        var idArray = userIds as ulong[] ?? userIds.ToArray();
        var reasonArray = reasons as string[] ?? reasons.ToArray();
        var amountArray = amounts as long[] ?? amounts.ToArray();

        if (idArray.Length != reasonArray.Length || reasonArray.Length != amountArray.Length)
            throw new ArgumentException("Cannot perform bulk operation. Arrays are not of equal length.");

        var userIdHashSet = new HashSet<ulong>(idArray.Length);
        await using var uow = _db.GetDbContext();
        for (var i = 0; i < idArray.Length; i++)
        {
            // i have to prevent same user changing more than once as it will cause db error
            if (userIdHashSet.Add(idArray[i]))
                InternalChange(idArray[i], null, null, null, reasonArray[i], amountArray[i], gamble, uow);
        }
        await uow.SaveChangesAsync();
    }
        
    public async Task RemoveBulkAsync(IEnumerable<ulong> userIds, IEnumerable<string> reasons, IEnumerable<long> amounts, bool gamble = false)
    {
        var idArray = userIds as ulong[] ?? userIds.ToArray();
        var reasonArray = reasons as string[] ?? reasons.ToArray();
        var amountArray = amounts as long[] ?? amounts.ToArray();

        if (idArray.Length != reasonArray.Length || reasonArray.Length != amountArray.Length)
            throw new ArgumentException("Cannot perform bulk operation. Arrays are not of equal length.");

        var userIdHashSet = new HashSet<ulong>(idArray.Length);
        await using var uow = _db.GetDbContext();
        for (var i = 0; i < idArray.Length; i++)
        {
            // i have to prevent same user changing more than once as it will cause db error
            if (userIdHashSet.Add(idArray[i]))
                InternalChange(idArray[i], null, null, null, reasonArray[i], -amountArray[i], gamble, uow);
        }
        await uow.SaveChangesAsync();
    }

    private async Task<bool> InternalRemoveAsync(ulong userId, string userName, string userDiscrim, string avatar, string reason, long amount, bool gamble = false)
    {
        if (amount < 0)
        {
            throw new ArgumentException("You can't remove negative amounts. Use AddAsync method for that.", nameof(amount));
        }

        bool result;
        await using var uow = _db.GetDbContext();
        result = InternalChange(userId, userName, userDiscrim, avatar, reason, -amount, gamble, uow);
        await uow.SaveChangesAsync();
        return result;
    }

    public Task<bool> RemoveAsync(ulong userId, string reason, long amount, bool gamble = false)
        => InternalRemoveAsync(userId, null, null, null, reason, amount, gamble);

    public Task<bool> RemoveAsync(IUser user, string reason, long amount, bool sendMessage = false, bool gamble = false)
        => InternalRemoveAsync(user.Id, user.Username, user.Discriminator, user.AvatarId, reason, amount, gamble);
}