using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using BTCPayServer.Data;
using Microsoft.EntityFrameworkCore;

namespace BTCPayServer.Services
{
    public class WalletRepository
    {
        private readonly ApplicationDbContextFactory _ContextFactory;

        public WalletRepository(ApplicationDbContextFactory contextFactory)
        {
            _ContextFactory = contextFactory ?? throw new ArgumentNullException(nameof(contextFactory));
        }

        public async Task SetWalletInfo(WalletId walletId, WalletBlobInfo blob)
        {
            ArgumentNullException.ThrowIfNull(walletId);
            using var ctx = _ContextFactory.CreateContext();
            var walletData = new WalletData() { Id = walletId.ToString() };
            walletData.SetBlobInfo(blob);
            var entity = await ctx.Wallets.AddAsync(walletData);
            entity.State = EntityState.Modified;
            try
            {
                await ctx.SaveChangesAsync();
            }
            catch (DbUpdateException) // Does not exists
            {
                entity.State = EntityState.Added;
                await ctx.SaveChangesAsync();
            }
        }

        public async Task<Dictionary<string, WalletTransactionInfo>> GetWalletTransactionsInfo(WalletId walletId, string[] transactionIds = null)
        {
            ArgumentNullException.ThrowIfNull(walletId);
            using var ctx = _ContextFactory.CreateContext();
            return (await ctx.WalletTransactions
                            .Where(w => w.WalletDataId == walletId.ToString())
                            .Where(data => transactionIds == null || transactionIds.Contains(data.TransactionId))
                            .Select(w => w)
                            .ToArrayAsync())
                            .ToDictionary(w => w.TransactionId, w => w.GetBlobInfo());
        }

        public async Task<WalletBlobInfo> GetWalletInfo(WalletId walletId)
        {
            ArgumentNullException.ThrowIfNull(walletId);
            using var ctx = _ContextFactory.CreateContext();
            var data = await ctx.Wallets
                 .Where(w => w.Id == walletId.ToString())
                 .Select(w => w)
                 .FirstOrDefaultAsync();
            return data?.GetBlobInfo() ?? new WalletBlobInfo();
        }

        public async Task SetWalletTransactionInfo(WalletId walletId, string transactionId, WalletTransactionInfo walletTransactionInfo)
        {
            ArgumentNullException.ThrowIfNull(walletId);
            ArgumentNullException.ThrowIfNull(transactionId);
            using var ctx = _ContextFactory.CreateContext();
            var walletData = new WalletTransactionData() { WalletDataId = walletId.ToString(), TransactionId = transactionId };
            walletData.SetBlobInfo(walletTransactionInfo);
            var entity = await ctx.WalletTransactions.AddAsync(walletData);
            entity.State = EntityState.Modified;
            try
            {
                await ctx.SaveChangesAsync();
            }
            catch (DbUpdateException) // Does not exists
            {
                entity.State = EntityState.Added;
                try
                {
                    await ctx.SaveChangesAsync();
                }
                catch (DbUpdateException) // the Wallet does not exists in the DB
                {
                    await SetWalletInfo(walletId, new WalletBlobInfo());
                    await ctx.SaveChangesAsync();
                }
            }
        }
    }
}