using Azaion.Common;
using Azaion.Common.Database;
using Azaion.Common.Entities;
using Azaion.Common.Extensions;
using Azaion.Common.Requests;
using LinqToDB;
using Newtonsoft.Json;

namespace Azaion.Services;

public interface IUserService
{
    Task RegisterUser(RegisterUserRequest request, CancellationToken cancellationToken = default);
    Task<User> ValidateUser(LoginRequest request, CancellationToken cancellationToken = default);
    Task<User?> GetByEmail(string? email, CancellationToken cancellationToken = default);
    Task UpdateHardware(string email, HardwareInfo? hardwareInfo = null, CancellationToken cancellationToken = default);
    Task UpdateQueueOffsets(string email, UserQueueOffsets queueOffsets, CancellationToken cancellationToken = default);
    Task<IEnumerable<User>> GetUsers(string? searchEmail, RoleEnum? searchRole, CancellationToken cancellationToken);
    Task<string> CheckHardwareHash(User user, GetResourceRequest request);
}

public class UserService(IDbFactory dbFactory, ICache cache) : IUserService
{
    public async Task RegisterUser(RegisterUserRequest request, CancellationToken cancellationToken = default)
    {
        await dbFactory.RunAdmin(async db =>
        {
            var existingUser = await db.Users.FirstOrDefaultAsync(u => u.Email == request.Email, token: cancellationToken);
            if (existingUser != null)
                throw new BusinessException(ExceptionEnum.EmailExists);

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

    public async Task<User?> GetByEmail(string? email, CancellationToken cancellationToken = default) =>
        await cache.GetFromCacheAsync(User.GetCacheKey(email),
            async () => await dbFactory.Run(async db =>
                await db.Users.FirstOrDefaultAsync(x => x.Email == email, cancellationToken)));

    public async Task<User> ValidateUser(LoginRequest request, CancellationToken cancellationToken = default) =>
        await dbFactory.Run(async db =>
        {
            var user = await db.Users.FirstOrDefaultAsync(x => x.Email == request.Email, token: cancellationToken);
            if (user == null)
                throw new BusinessException(ExceptionEnum.NoEmailFound);

            if (request.Password.ToHash() != user.PasswordHash)
                throw new BusinessException(ExceptionEnum.WrongPassword);

            return user;
        });


    public async Task UpdateHardware(string email, HardwareInfo? hardware = null, CancellationToken cancellationToken = default)
    {
        await dbFactory.RunAdmin(async db =>
        {
            var hardwareStr = hardware == null ? "" : JsonConvert.SerializeObject(hardware);

            await db.Users.UpdateAsync(x => x.Email == email,
                u => new User
                {
                    Hardware = hardwareStr
                }, token: cancellationToken);
        });
        cache.Invalidate(User.GetCacheKey(email));
    }

    public async Task UpdateQueueOffsets(string email, UserQueueOffsets queueOffsets, CancellationToken cancellationToken = default)
    {
        await dbFactory.RunAdmin(async db =>
        {
            var userConfig = await db.Users.Where(x => x.Email == email).Select(x => x.UserConfig).FirstOrDefaultAsync(token: cancellationToken);
            userConfig ??= new UserConfig();
            userConfig.QueueOffsets = queueOffsets;

            await db.Users.UpdateAsync(x => x.Email == email,
                u => new User
                {
                    UserConfig = userConfig
                }, token: cancellationToken);
        });
        cache.Invalidate(User.GetCacheKey(email));
    }

    public async Task<IEnumerable<User>> GetUsers(string? searchEmail, RoleEnum? searchRole, CancellationToken cancellationToken) =>
        await dbFactory.Run(async db =>
            await db.Users
                .WhereIf(!string.IsNullOrEmpty(searchEmail),
                    u => u.Email.ToLower().Contains(searchEmail!.ToLower()))
                .WhereIf(searchRole != null,
                    u => u.Role == searchRole)
                .ToListAsync(token: cancellationToken));

    public async Task<string> CheckHardwareHash(User user, GetResourceRequest request)
    {
        var requestHWHash = Security.GetHWHash(request.Hardware);

        //For the new users Hardware would be empty, fill it with actual hardware on the very first request
        if (string.IsNullOrEmpty(user.Hardware))
        {
            await UpdateHardware(user.Email, request.Hardware);
            cache.Invalidate(User.GetCacheKey(user.Email));
            return requestHWHash;
        }

        var userHW = JsonConvert.DeserializeObject<HardwareInfo>(user.Hardware);
        var userHWHash = Security.GetHWHash(userHW!);
        if (userHWHash != requestHWHash)
            throw new BusinessException(ExceptionEnum.HardwareIdMismatch);
        return userHWHash;
    }
}