using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Transactions;
using BlueWest.Collections;
using MessagePack;

namespace BlueWest.Data
{
    [MessagePackObject]
    public class UserList: DataObject
    {
        [Key(9)] public readonly FastDictionary<int, User> Users;

        [IgnoreMember] public int Length = 0;

        public UserList(FastDictionary<int, User> users)
        {
            Users = users;
        }

        private int GetIndexById(int userId)
        {
            var keys = Users.Keys;

            foreach (var key in keys)
            {
                if (key == userId) return key;
            }

            return -1;
        }

        public DataQueryResult<User> GetUserById(int id)
        {
            if (Users.ContainsKey(id)) return new DataQueryResult<User>(Users[id], true);
            return new DataQueryResult<User>(null, false, "Can't find a user with the provided id.");
        }

        public bool RemoveUser(int userId)
        {
            if (Users.ContainsKey(userId))
            {
                Users.Remove(userId);
                return true;
            }

            return false;
        }

        internal bool HasUser(int userId)
        {
            return Users.Contains(userId);
        }

        public DataQueryResult<User> UpdateUser(int userId, UserUpdateDto userUpdate)
        {
            if (Users.ContainsKey(userId))
            {
                Users[userId].Update(userUpdate);
                return new DataQueryResult<User>(Users[userId], true);
            }
            
            return new DataQueryResult<User>(null, false);
        }


        internal bool UserHasTransaction(int userId, int transactionId) => HasUser(userId) && Users[userId].FinanceTransactions.Contains(transactionId);

        public DataQueryResult<FinanceTransaction> GetTransactionById(int userId, int transactionId)
        {
            if(!HasUser(userId)) return new DataQueryResult<FinanceTransaction>(new FinanceTransaction(), false, "Can't find a user with the provided id.");

            if (UserHasTransaction(userId, transactionId)) return new DataQueryResult<FinanceTransaction>(Users[userId].FinanceTransactions[transactionId]);

            return new DataQueryResult<FinanceTransaction>(new FinanceTransaction(), false, "Can't find a transaction with the provided id.");
        }

        public User AddUser(int userId, UserUpdateDto userUpdateDto)
        {
            if (Users.ContainsKey(userId))
            {
                Users[userId].Update(userUpdateDto);
                return Users[userId];
            }
            
            var id = userId != -1 ? userId : Length + 1;

            var newUser = new User(userUpdateDto);

            Users.Add(Length, newUser);

            Length++;

            return newUser;
        }

        const string NoIdError = "No transaction was found with the specified id";

        public DataQueryResult<FinanceTransaction> AddFinanceTransaction(int userId, FinanceTransactionInsertDto financeTransactionDto)
        {
            if (Users.ContainsKey(userId))
            {
                var now = TimeSpan.FromTicks(DateTime.Now.Ticks);
                var financeTransaction = new FinanceTransaction(financeTransactionDto, now, Users[userId].Id);
                Users[userId].AddTransaction(financeTransaction);
                return new DataQueryResult<FinanceTransaction>(financeTransaction);
            }

            return new DataQueryResult<FinanceTransaction>(new FinanceTransaction(), false,
                "no transaction with the provided id");
        }


        public ImmutableArray<FinanceTransaction> GetUserTransactions(int userId)
        {
            if (Users.ContainsKey(userId))
            {
                return Users[userId].FinanceTransactions.Values.ToImmutableArray();
            }

            return new ImmutableArray<FinanceTransaction>();
        }

    }
}