using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Threading.Tasks;
using CompatBot.Database;

namespace CompatBot.Providers
{
    internal static class ModProvider
    {
        private static readonly Dictionary<ulong, Moderator> mods;
        public static ReadOnlyDictionary<ulong, Moderator> Mods => new ReadOnlyDictionary<ulong, Moderator>(mods);

        static ModProvider()
        {
            mods = BotDb.Instance.Moderator.ToDictionary(m => m.DiscordId, m => m);
        }

        public static bool IsMod(ulong userId) => mods.ContainsKey(userId);

        public static bool IsSudoer(ulong userId) => mods.TryGetValue(userId, out var mod) && mod.Sudoer;

        public static async Task<bool> AddAsync(ulong userId)
        {
            if (IsMod(userId))
                return false;

            var db = BotDb.Instance;
            var result = await db.Moderator.AddAsync(new Moderator {DiscordId = userId}).ConfigureAwait(false);
            await db.SaveChangesAsync().ConfigureAwait(false);
            lock (mods)
            {
                if (IsMod(userId))
                    return false;
                mods[userId] = result.Entity;
            }
            return true;
        }

        public static async Task<bool> RemoveAsync(ulong userId)
        {
            if (!mods.TryGetValue(userId, out var mod))
                return false;

            var db = BotDb.Instance;
            db.Moderator.Remove(mod);
            await db.SaveChangesAsync().ConfigureAwait(false);
            lock (mods)
            {
                if (IsMod(userId))
                    mods.Remove(userId);
                else
                    return false;
            }
            return true;
        }

        public static async Task<bool> MakeSudoerAsync(ulong userId)
        {
            if (!mods.TryGetValue(userId, out var mod) || mod.Sudoer)
                return false;

            mod.Sudoer = true;
            await BotDb.Instance.SaveChangesAsync().ConfigureAwait(false);
            return true;
        }

        public static async Task<bool> UnmakeSudoerAsync(ulong userId)
        {
            if (!mods.TryGetValue(userId, out var mod) || !mod.Sudoer)
                return false;

            mod.Sudoer = false;
            await BotDb.Instance.SaveChangesAsync().ConfigureAwait(false);
            return true;
        }
    }
}