using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using DeukBot4.Database;
using DeukBot4.MessageHandlers.CommandHandler.RequestStructure;
using DeukBot4.MessageHandlers.Permissions;
using DeukBot4.Utilities;
using Discord;
using Npgsql;

namespace DeukBot4.MessageHandlers.CommandHandler
{
    public static class TagStorage
    {
        public class ServerTags
        {
            private readonly Dictionary<string, string> Tags = new Dictionary<string, string>();
            private ulong ServerId { get; }

            public ServerTags(ulong serverId)
            {
                ServerId = serverId;
            }

            public ServerTags(ulong serverId, Dictionary<string, string> tags)
                :this(serverId)
            {
                Tags = tags;
            }

            private static string CleanKey(string key)
            {
                return key.ToLowerInvariant();
            }

            public static readonly string[] ReservedTags = new[] {"create", "delete", "remove"};
            public (bool success, string result) AddTag(string key, string value)
            {
                var parsedTag = CleanKey(key);
                if (ReservedTags.Contains(parsedTag))
                {
                    return (false, $"You can't use keyword {parsedTag}, that's a reserved tag");
                }
                if (Tags.ContainsKey(parsedTag))
                {
                    return (false, "A tag with that name already exists");
                }
                Tags.Add(parsedTag, value);
                using (var db = new DatabaseConnection())
                {
                    using (var command = new NpgsqlCommand())
                    {
                        command.Connection = db;
                        command.CommandText = "INSERT INTO tags (server_id, key, value) VALUES (@id, @key, @value)";
                        command.Parameters.AddWithValue("@id", ServerId.ToLong());
                        command.Parameters.AddWithValue("@key", parsedTag);
                        command.Parameters.AddWithValue("@value", value);
                        command.ExecuteNonQuery();
                    }
                }
                return (true, "");
            }

            public (bool success, string result) RemoveTag(string key)
            {
                var parsedTag = CleanKey(key);
                if (!Tags.ContainsKey(parsedTag))
                {
                    return (false, "No tag with that name exists");
                }
                Tags.Remove(parsedTag);
                using (var db = new DatabaseConnection())
                {
                    using (var command = new NpgsqlCommand())
                    {
                        command.Connection  = db;
                        command.CommandText = "DELETE FROM tags WHERE server_id = @id AND key = @key";
                        command.Parameters.AddWithValue("@id", ServerId.ToLong());
                        command.Parameters.AddWithValue("@key", parsedTag);
                        var res = command.ExecuteNonQuery();
                    }
                }

                return (true, "");
            }

            public string GetTag(string key)
            {
                var parsedTag = CleanKey(key);
                if (!Tags.TryGetValue(parsedTag, out var value))
                {
                    return "No tag by that name exists";
                }

                return value;
            }

            public List<string> TagList()
            {
                return Tags.Keys.OrderBy(x => x).ToList();
            }
        }

        private static readonly Dictionary<ulong, ServerTags> ServerCache = new Dictionary<ulong, ServerTags>();

        public static void BuildTags()
        {
            using (var conn = new DatabaseConnection())
            {
                using (var command = new NpgsqlCommand())
                {
                    command.Connection = conn;
                    command.CommandText = "SELECT server_id, key, value FROM tags";
                    var reader = command.ExecuteReader();
                    var res = new Dictionary<ulong, Dictionary<string, string>>();
                    while (reader.Read())
                    {
                        var id = reader.GetInt64(0).ToUlong();
                        var key = reader.GetString(1);
                        var value = reader.GetString(2);
                        if (!res.TryGetValue(id, out var dic))
                        {
                            dic = new Dictionary<string, string>();
                            res.Add(id, dic);
                        }
                        dic.Add(key, value);
                    }

                    foreach (var dic in res)
                    {
                        ServerCache.Add(dic.Key, new ServerTags(dic.Key, dic.Value));
                    }
                }
            }
        }

        public static async Task AddTag(CommandRequest cmd)
        {
            var channel = cmd.OriginalMessage.Channel as IGuildChannel;
            if (channel == null)
                return;
            var serverId = channel.GuildId;
            if (!ServerCache.TryGetValue(serverId, out var serverTags))
            {
                serverTags = new ServerTags(serverId);
                ServerCache.Add(serverId, serverTags);
            }

            var key   = cmd.Parameters[0].AsString();
            var value = cmd.Parameters[1].AsString();
            var result = serverTags.AddTag(key, value);
            if (!result.success)
            {
                cmd.SendSimpleEmbed("Tag Creation", "Something went wrong: " + result.result);
            }
            else
            {
                cmd.SendSimpleEmbed("Tag Creation","Success! Added tag with key: " + key);
            }
        }

        public static async Task RemoveTag(CommandRequest cmd)
        {
            var channel = cmd.OriginalMessage.Channel as IGuildChannel;
            if (channel == null)
                return;
            var serverId = channel.GuildId;
            if (!ServerCache.TryGetValue(serverId, out var serverTags))
            {
                serverTags = new ServerTags(serverId);
                ServerCache.Add(serverId, serverTags);
            }

            var key    = cmd.Parameters[0].AsString();
            var result = serverTags.RemoveTag(key);
            if (!result.success)
            {
                cmd.SendSimpleEmbed("Tag Deletion","Something went wrong: " + result.result);
            }
            else
            {
                cmd.SendSimpleEmbed("Tag Deletion","Success! Removed tag with key: " + key);
            }

        }

        public static async Task GetTag(CommandRequest cmd)
        {
            var channel = cmd.OriginalMessage.Channel as IGuildChannel;
            if (channel == null)
                return;
            var serverId = channel.GuildId;
            if (!ServerCache.TryGetValue(serverId, out var serverTags))
            {
                serverTags = new ServerTags(serverId);
                ServerCache.Add(serverId, serverTags);
            }

            var split = cmd.Parameters[0].AsString().Split(" ");
            var first = split[0].ToLowerInvariant();
            if (first == "create")
            {
                var perms = await PermissionValidator.GetUserPermissionLevel(cmd.OriginalMessage);
                if (perms < PermissionLevel.Helper)
                    return;
                var keyword = split[1];
                var rest = split.Skip(2).ToArray().Join(" ");
                var result = serverTags.AddTag(keyword, rest);
                if (!result.success)
                {
                    cmd.SendSimpleEmbed("Tag Creation", "Something went wrong: " + result.result);
                }
                else
                {
                    cmd.SendSimpleEmbed("Tag Creation","Success! Added tag with key: " + keyword);
                }
                return;
            }
            if (first == "remove" || first == "delete")
            {
                var perms = await PermissionValidator.GetUserPermissionLevel(cmd.OriginalMessage);
                if (perms < PermissionLevel.Helper)
                    return;

                var keyword = split[1];
                var result  = serverTags.RemoveTag(keyword);
                if (!result.success)
                {
                    cmd.SendSimpleEmbed("Tag Deletion","Something went wrong: " + result.result);
                }
                else
                {
                    cmd.SendSimpleEmbed("Tag Deletion","Success! Removed tag with key: " + keyword);
                }
                return;
            }

            cmd.SendMessageAsync(serverTags.GetTag(first));
        }

        public static async Task GetTags(CommandRequest cmd)
        {
            var channel = cmd.OriginalMessage.Channel as IGuildChannel;
            if (channel == null)
                return;
            var serverId = channel.GuildId;
            if (!ServerCache.TryGetValue(serverId, out var serverTags))
            {
                return;
            }
            var tags = serverTags.TagList();
            var eb = EmbedFactory.GetStandardEmbedBuilder();
            eb.Title = "This Server Has The Following Tags";
            eb.Description = tags.Join("\n");
            cmd.OriginalMessage.Channel.SendMessageAsync("", embed: eb.Build());
        }

    }
}