using Azaion.Common;
using Azaion.Common.Database;
using Azaion.Common.Entities;
using Azaion.Common.Requests;
using LinqToDB;

namespace Azaion.Services;

public interface IUserService
{
    Task RegisterUser(RegisterUserRequest request, CancellationToken cancellationToken = default);
    Task<User?> ValidateUser(GetResourceRequest request, CancellationToken cancellationToken = default);
}

public class UserService(IDbFactory dbFactory) : IUserService
{
    public async Task RegisterUser(RegisterUserRequest request, CancellationToken cancellationToken = default)
    {
        await dbFactory.Run(async db =>
        {
            var existingUser = await db.Users.FirstOrDefaultAsync(u => u.Username == request.Email, token: cancellationToken);
            if (existingUser != null)
                throw new BusinessException(ExceptionEnum.UserExists, "User already exists");

            await db.InsertAsync(new User
            {
                Username = request.Email,
                PasswordHash = request.Password.ToHash(),
                Role = request.Role
            }, token: cancellationToken);
        });
    }

    public async Task<User?> ValidateUser(GetResourceRequest request, CancellationToken cancellationToken = default) =>
        await dbFactory.Run(async db =>
        {
            var user = await db.Users.FirstOrDefaultAsync(x => x.Username == request.Username, token: cancellationToken);
            if (user == null)
                throw new BusinessException(ExceptionEnum.NoUserFound, "No user found");

            if (request.Password.ToHash() != user.PasswordHash)
                throw new BusinessException(ExceptionEnum.PasswordIncorrect, "Passwords do not match");

            //If user's hardware Id is empty (usually on the first time login), then write down user
            if (string.IsNullOrEmpty(user.HardwareId))
                await db.Users.UpdateAsync(x => x.Username == request.Username, u => new User{HardwareId = request.HardwareId}, token: cancellationToken);
            else
            {
                //But if hardware Id exists, it should match with request
                if (user.HardwareId != request.HardwareId)
                    throw new BusinessException(ExceptionEnum.HardwareIdMismatch, "Hardware id mismatch");
            }

            return user;
        });
}