Govor/Govor.Application/Services/Friends/FriendRequestCommandService.cs

using Govor.Application.Exceptions.FriendsService;
using Govor.Application.Interfaces.Friends;
using Govor.Core.Models;
using Govor.Core.Repositories.Friendships;
using Govor.Data.Repositories.Exceptions;

namespace Govor.Application.Services.Friends;

public class FriendRequestCommandService : IFriendRequestCommandService
{
    private readonly IFriendshipsRepository _friendshipsRepository;

    public FriendRequestCommandService(IFriendshipsRepository friendshipsRepository)
    {
        _friendshipsRepository = friendshipsRepository;
    }
    
    public async Task<Friendship> SendAsync(Guid fromUserId, Guid toUserId)
    {
        if (fromUserId == toUserId)
            throw new InvalidOperationException("Cannot send a request to self user");
        
        var friendship = await _friendshipsRepository.GetFriendshipAsync(fromUserId, toUserId);

        if (friendship is null)
        {
            friendship = new Friendship
            {
                Id = Guid.NewGuid(),
                RequesterId = fromUserId,
                AddresseeId = toUserId,
                Status = FriendshipStatus.Pending
            };
            await _friendshipsRepository.AddAsync(friendship);
        }
        else
        {
            if (friendship.Status == FriendshipStatus.Pending || friendship.Status == FriendshipStatus.Accepted
                                                              || friendship.Status == FriendshipStatus.Blocked)
            {
                throw new RequestAlreadySentException(fromUserId, toUserId);
            }
            
            friendship.RequesterId = fromUserId;
            friendship.AddresseeId = toUserId;
            friendship.Status = FriendshipStatus.Pending;
        
            await _friendshipsRepository.UpdateAsync(friendship);
        }

        return friendship;
    }

    public async Task<Friendship> AcceptAsync(Guid requestId, Guid currentUserId)
    {
        try
        {
            var friendship = await _friendshipsRepository.GetByIdAsync(requestId);

            if (friendship.AddresseeId != currentUserId)
                throw new UnauthorizedAccessException("You cannot accept this request");

            if (friendship.Status != FriendshipStatus.Pending)
                throw new InvalidOperationException("Request is already accepted");

            friendship.Status = FriendshipStatus.Accepted;
            await _friendshipsRepository.UpdateAsync(friendship);
            
            return friendship;
        }
        catch (NotFoundByKeyException<Guid> ex)
        {
            throw new InvalidOperationException("Friendship not found! You cant accept request!", ex);
        }
    }

    public async Task<Friendship> RejectAsync(Guid requestId, Guid currentUserId)
    {
        try
        {
            var friendship = await _friendshipsRepository.GetByIdAsync(requestId);

            if (friendship.AddresseeId != currentUserId)
                throw new UnauthorizedAccessException("You cannot accept this request");

            if (friendship.Status != FriendshipStatus.Pending && friendship.Status != FriendshipStatus.Rejected)
                throw new InvalidOperationException($"Request is already {friendship.Status}");

            friendship.Status = FriendshipStatus.Rejected;
            await _friendshipsRepository.UpdateAsync(friendship);
            return friendship;
        }
        catch (NotFoundByKeyException<Guid> ex)
        {
            throw new InvalidOperationException("Friendship not found! You cant reject request!", ex);
        }
    }
}