using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using Dapper;
using MySql.Data.MySqlClient;

namespace JetKarmaBot
{
    public class Db
    {
        Dictionary<long, Chat> m_Chats;
        public IReadOnlyDictionary<long, Chat> Chats => m_Chats;
        public void AddChat(Chat chat)
        {
            lock (m_SyncRoot)
            if (!m_Chats.ContainsKey(chat.ChatId))
            {
                Conn.Execute(@"INSERT INTO chat
                            (chatid)
                            VALUES
                            (@ChatId)",
                            chat);
                m_Chats.Add(chat.ChatId, chat);
            }
        }
        
        Dictionary<long, User> m_Users;
        public IReadOnlyDictionary<long, User> Users => m_Users;
        public void AddUser(User user)
        {
            lock (m_SyncRoot)
                if (!m_Users.ContainsKey(user.UserId))
                {
                    Conn.Execute(@"INSERT INTO user
                            (userid)
                            VALUES
                            (@UserId)",
                                user);
                    m_Users.Add(user.UserId, user);
                }
        }
        Dictionary<byte, AwardType> m_AwardTypes;
        public byte DefaultAwardTypeId { get; } = 1;
        public IReadOnlyDictionary<byte, AwardType> AwardTypes => m_AwardTypes;
        public IReadOnlyDictionary<string, AwardType> AwardTypesByCommandName { get; private set; }

        public int CountAwards(long userId, byte awardTypeId)
        {
            return Conn.QuerySingle<int?>
            (
                "SELECT SUM(amount) FROM award WHERE toid = @userId AND awardtypeid = @awardTypeId",
                new { userId, awardTypeId }
            ) ?? 0;
        }

        public byte GetAwardTypeId(string name)
            => AwardTypesByCommandName.GetOrDefault(name)?.AwardTypeId ?? DefaultAwardTypeId;

        public bool AddAward(byte awardTypeId, long fromId, long toId, long chatId)
        {
            AddChat(new Chat() {  ChatId = chatId });
            AddUser(new User() {  UserId = fromId});
            AddUser(new User() {  UserId = toId });

            int affected = Conn.ExecuteScalar<int>(
                @"INSERT INTO award
                (chatid, fromid, toid, awardtypeid, amount)
                VALUES
                (@chatId, @fromId, @toId, @awardTypeId, 1)",
                new { awardTypeId, fromId, toId, chatId });
            return affected == 1;
        }

        #region types
        public class Chat
        {
            public long ChatId { get; set; }
        }

        public class User
        {
            public long UserId { get; set; }
        }

        public class AwardType
        {
            public byte AwardTypeId { get; set; }
            public string CommandName { get; set; }
            public string Name { get; set; }
            public string Symbol { get; set; }
            public string Description { get; set; }
        }

        public class Award
        {
            public int AwardId { get; set; }
            public byte AwardTypeId { get; set; }
            public long FromId { get; set; }
            public long ToId { get; set; }
            public long ChatId { get; set; }
            public byte Amount { get; set; }
        }

        #endregion

        #region service
        public Db(Config cfg)
        {
            Log("Initializing...");
            Conn = new MySqlConnection(cfg.ConnectionString);
            Conn.ExecuteScalar("select 1");
            Load();
            Log("Initialized!");
        }

        object m_SyncRoot = new object();

        IDbConnection Conn { get; }
        void Load()
        {
            Log("Populating cache...");
            m_Chats = Conn.Query<Chat>("SELECT * FROM chat").ToDictionary(u => u.ChatId);
            m_Users = Conn.Query<User>("SELECT * FROM user").ToDictionary(s => s.UserId);
            m_AwardTypes = Conn.Query<AwardType>("SELECT * FROM awardtype").ToDictionary(c => c.AwardTypeId);
            AwardTypesByCommandName = m_AwardTypes.Values.ToDictionary(kvp => kvp.CommandName);
            Log("Cache populated!");
        }
        #endregion

        void Log (string Message) => Console.WriteLine($"[{nameof(Db)}]: {Message}");
    }
}