using Microsoft.Extensions.Localization;

using PrivaPub.ClientModels;
using PrivaPub.Models.User;
using PrivaPub.Resources;
using PrivaPub.StaticServices;

namespace PrivaPub.Services.ClientToServer.Public
{
	public interface IPublicAvatarUsersService
	{
		Task<WebResult> GetLocalAvatar(UserPolicyType userPolicyType, string actor, CancellationToken token);
		Task<IEnumerable<Avatar>> GetLocalAvatars(UserPolicyType userPolicyType, CancellationToken token);

		Task<WebResult> GetForeignAvatar(UserPolicyType userPolicyType, string actor, CancellationToken token);
		Task<IEnumerable<ForeignAvatar>> GetForeignAvatars(UserPolicyType userPolicyType, CancellationToken token);

		Task<IEnumerable<Avatar>> GetRootAvatars(string rootUserId, CancellationToken token);
	}

	public class PublicAvatarUsersService : IPublicAvatarUsersService
	{
		readonly DbEntities _dbEntities;
		readonly IStringLocalizer<GenericRes> _localizer;
		readonly ILogger<PublicAvatarUsersService> _logger;

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

		public async Task<WebResult> GetLocalAvatar(UserPolicyType userPolicyType, string actor, CancellationToken token)
		{
			var result = new WebResult();
			try
			{
				var query = _dbEntities.Avatars;
				switch (userPolicyType)
				{
					case UserPolicyType.IsUser:
						query.Match(a => !a.DeletionAt.HasValue && a.UserName == actor);
						break;
					case UserPolicyType.IsModerator:
						query.Match(a => !a.DeletionAt.HasValue && a.UserName == actor);
						break;
					case UserPolicyType.IsAdmin:
						query.Match(a => a.UserName == actor);
						break;
				}
				var avatar = await query.ExecuteFirstAsync(token);
				if (avatar == default)
					return result.Invalidate(_localizer["User '{0}' not found.", actor], StatusCodes.Status404NotFound);
				result.Data = avatar;
				return result;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PublicAvatarUsersService)}.{nameof(GetLocalAvatar)}");
				return result.Invalidate(_localizer["Error: {0}", ex.ToString()], exception: ex);
			}
		}

		public async Task<IEnumerable<Avatar>> GetLocalAvatars(UserPolicyType userPolicyType, CancellationToken token)
		{
			try
			{
				var query = _dbEntities.Avatars;
				switch (userPolicyType)
				{
					case UserPolicyType.IsUser:
						query.Match(a => !a.DeletionAt.HasValue);
						break;
					case UserPolicyType.IsModerator:
						query.Match(a => !a.DeletionAt.HasValue);
						break;
					case UserPolicyType.IsAdmin:
						break;
				}
				var avatars = await query.ExecuteAsync(token);
				return avatars;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PublicAvatarUsersService)}.{nameof(GetLocalAvatars)}");
				return Enumerable.Empty<Avatar>();
			}
		}

		public async Task<WebResult> GetForeignAvatar(UserPolicyType userPolicyType, string actor, CancellationToken token)
		{
			var result = new WebResult();
			try
			{
				var query = _dbEntities.ForeignAvatars;
				switch (userPolicyType)
				{
					case UserPolicyType.IsUser:
						query.Match(a => !a.DeletionAt.HasValue && a.UserName == actor);
						break;
					case UserPolicyType.IsModerator:
						query.Match(a => !a.DeletionAt.HasValue && a.UserName == actor);
						break;
					case UserPolicyType.IsAdmin:
						query.Match(a => a.UserName == actor);
						break;
				}
				var avatar = await query.ExecuteFirstAsync(token);
				if (avatar == default)
					return result.Invalidate(_localizer["User '{0}' not found.", actor], StatusCodes.Status404NotFound);
				result.Data = avatar;
				return result;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PublicAvatarUsersService)}.{nameof(GetForeignAvatar)}");
				return result.Invalidate(_localizer["Error: {0}", ex.ToString()], exception: ex);
			}
		}

		public async Task<IEnumerable<ForeignAvatar>> GetForeignAvatars(UserPolicyType userPolicyType, CancellationToken token)
		{
			try
			{
				var query = _dbEntities.ForeignAvatars;
				switch (userPolicyType)
				{
					case UserPolicyType.IsUser:
						query.Match(a => !a.DeletionAt.HasValue);
						break;
					case UserPolicyType.IsModerator:
						query.Match(a => !a.DeletionAt.HasValue);
						break;
					case UserPolicyType.IsAdmin:
						break;
				}
				var foreignAvatars = await query.ExecuteAsync(token);
				return foreignAvatars;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PublicAvatarUsersService)}.{nameof(GetForeignAvatars)}");
				return Enumerable.Empty<ForeignAvatar>();
			}
		}

		public async Task<IEnumerable<Avatar>> GetRootAvatars(string rootUserId, CancellationToken token)
		{
			try
			{
				var rootUser = _dbEntities.RootUsers.MatchID(rootUserId).ExecuteFirstAsync(token);
				if (rootUser == default)
					return Enumerable.Empty<Avatar>();
				var rootToAvatars = await _dbEntities.RootToAvatars.Match(ra => ra.RootId == rootUserId).ExecuteAsync(token);
				if (rootToAvatars.Count == 0)
					return Enumerable.Empty<Avatar>();
				var avatarIds = rootToAvatars.Select(ra => ra.AvatarId).ToArray();
				var avatars = await _dbEntities.Avatars
					.Match(a => avatarIds.Contains(a.ID))
					.ProjectExcluding(a => a.Settings)
					.ExecuteAsync(token);
				return avatars;
			}
			catch (Exception ex)
			{
				_logger.LogError(ex, $"{nameof(PublicAvatarUsersService)}.{nameof(GetRootAvatars)}");
				return Enumerable.Empty<Avatar>();
			}
		}
	}
}