using Microsoft.Extensions.Localization;

using MongoDB.Entities;

using PrivaPub.ClientModels;
using PrivaPub.ClientModels.User;
using PrivaPub.ClientModels.User.Avatar;
using PrivaPub.Models.User;
using PrivaPub.Resources;
using PrivaPub.Services.Federation;
using PrivaPub.StaticServices;

namespace PrivaPub.Services.ClientToServer.Private
{
	public interface IPrivateAvatarUsersService
	{
		Task<WebResult> UpdateAvatar(UpdateAvatarForm form);
		Task<WebResult> InsertAvatar(InsertAvatarForm form);
		Task<WebResult> GetRootAvatars(string rootUserId, CancellationToken token);
	}

	public class PrivateAvatarUsersService : IPrivateAvatarUsersService
	{
		readonly ILocalActorService _localActors;
		readonly DbEntities _dbEntities;
		readonly IStringLocalizer<GenericRes> _localizer;
		readonly ILogger<PrivateAvatarUsersService> _logger;

		public PrivateAvatarUsersService(ILocalActorService localActors,
			DbEntities dbEntities,
			IStringLocalizer<GenericRes> localizer,
			ILogger<PrivateAvatarUsersService> logger)
		{
			_localActors = localActors;
			_dbEntities = dbEntities;
			_localizer = localizer;
			_logger = logger;
		}

		public async Task<WebResult> InsertAvatar(InsertAvatarForm form)
		{
			var result = new WebResult();
			try
			{
				var userName = form.UserName?.Trim().ToLowerInvariant();
				if (string.IsNullOrEmpty(userName) || !userName.All(c => char.IsAsciiLetterOrDigit(c) || c == '_'))
					return result.Invalidate(_localizer["The username may contain only letters, digits and underscores."]);

				if (await _localActors.IsUserNameTaken(userName, default))
					return result.Invalidate(_localizer["The username '{0}' is already take.", userName]);

				if (!await IsValidRootUser(form.RootId))
					return result.Invalidate(_localizer["You can't do this action because of your account status."]);

				var (privateKey, publicKey) = Keys.NewKeyPair();
				var newAvatar = new Avatar
				{
					Name = form.Name,
					UserName = userName,
					Biography = form.Biography,
					Fields = form.Fields,
					PersonalNote = form.PersonalNote,
					PrivateKey = privateKey,
					PublicKey = publicKey,
					Domain = _localActors.BaseAddress
				};
				if (form.Settings is { IsDefault: false })
					newAvatar.Settings = ToSettings(form.Settings);

				var actor = _localActors.FromAvatar(newAvatar);
				newAvatar.Url = actor.Uri;
				newAvatar.InboxURL = actor.Inbox;
				newAvatar.OutboxURL = actor.Outbox;

				await DB.Default.SaveAsync(newAvatar);
				await DB.Default.SaveAsync(new RootToAvatar { RootId = form.RootId, AvatarId = newAvatar.ID });

				result.Data = ToView(newAvatar);
				return result;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(InsertAvatar)}");
				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
			}
		}

		public async Task<WebResult> UpdateAvatar(UpdateAvatarForm form)
		{
			var result = new WebResult();
			try
			{
				if (!await IsValidRootUser(form.RootId))
					return result.Invalidate(_localizer["You can't do this action because of your account status."]);

				var owns = await _dbEntities.RootToAvatars
					.Match(ra => ra.RootId == form.RootId && ra.AvatarId == form.AvatarId)
					.ExecuteAnyAsync();
				if (!owns)
					return result.Invalidate(_localizer["Avatar not found."], StatusCodes.Status404NotFound);

				var avatar = await _dbEntities.Avatars.MatchID(form.AvatarId).ExecuteFirstAsync();
				if (avatar == default || avatar.DeletionAt.HasValue)
					return result.Invalidate(_localizer["Avatar not found."], StatusCodes.Status404NotFound);

				avatar.Name = form.Name;
				avatar.Biography = form.Biography;
				avatar.Fields = form.Fields ?? new();
				avatar.PersonalNote = form.PersonalNote;
				if (form.Settings != default)
					avatar.Settings = ToSettings(form.Settings);
				avatar.UpdatedAt = DateTime.UtcNow;
				await DB.Default.SaveAsync(avatar);

				result.Data = ToView(avatar);
				return result;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(UpdateAvatar)}");
				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
			}
		}

		public async Task<WebResult> GetRootAvatars(string rootUserId, CancellationToken token)
		{
			var result = new WebResult();
			try
			{
				var avatarIds = (await _dbEntities.RootToAvatars.Match(ra => ra.RootId == rootUserId).ExecuteAsync(token))
					.Select(ra => ra.AvatarId)
					.ToList();
				var avatars = avatarIds.Count == 0
					? new List<Avatar>()
					: await _dbEntities.Avatars.Match(a => avatarIds.Contains(a.ID) && !a.DeletionAt.HasValue).ExecuteAsync(token);
				result.Data = avatars.Select(ToView).ToList();
				return result;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(GetRootAvatars)}");
				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
			}
		}

		async ValueTask<bool> IsValidRootUser(string rootUserId) =>
			!string.IsNullOrEmpty(rootUserId)
			&& await _dbEntities.RootUsers.MatchID(rootUserId)
				.Match(ru => !ru.DeletedAt.HasValue && !ru.IsBanned)
				.ExecuteAnyAsync();

		static AvatarSettings ToSettings(ViewAvatarSettings settings) => new()
		{
			IsDefault = settings.IsDefault,
			DarkThemeIndexColour = settings.DarkThemeIndexColour,
			IconsThemeIndexColour = settings.IconsThemeIndexColour,
			LanguageCode = settings.LanguageCode,
			LightThemeIndexColour = settings.LightThemeIndexColour,
			PreferSystemTheming = settings.PreferSystemTheming,
			ThemeIsDarkGray = settings.ThemeIsDarkGray,
			ThemeIsDarkMode = settings.ThemeIsDarkMode,
			ThemeIsLightGray = settings.ThemeIsLightGray
		};

		ViewAvatar ToView(Avatar avatar) => new()
		{
			Id = avatar.ID,
			Url = avatar.Url,
			Handle = _localActors.FromAvatar(avatar).Handle,
			Name = avatar.Name,
			UserName = avatar.UserName,
			Biography = avatar.Biography,
			Fields = avatar.Fields,
			PictureURL = avatar.PictureURL,
			ThumbnailURL = avatar.ThumbnailURL,
			SharedPersonalContacts = avatar.SharedPersonalContacts,
			AccountState = (ViewAvatarState)(int)avatar.AccountState,
			ServerType = ViewAvatarServer.PrivaPub,
			Settings = new()
			{
				IsDefault = avatar.Settings.IsDefault,
				LanguageCode = avatar.Settings.LanguageCode,
				IconsThemeIndexColour = avatar.Settings.IconsThemeIndexColour,
				LightThemeIndexColour = avatar.Settings.LightThemeIndexColour,
				DarkThemeIndexColour = avatar.Settings.DarkThemeIndexColour,
				PreferSystemTheming = avatar.Settings.PreferSystemTheming,
				ThemeIsDarkMode = avatar.Settings.ThemeIsDarkMode,
				ThemeIsDarkGray = avatar.Settings.ThemeIsDarkGray,
				ThemeIsLightGray = avatar.Settings.ThemeIsLightGray
			},
			UpdatedAt = avatar.UpdatedAt,
			CreatedAt = avatar.CreatedAt
		};
	}
}