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

namespace Azaion.Services;

public interface IUserService
{
    Task RegisterUser(RegisterUserRequest request, CancellationToken ct = default);
    Task<User> ValidateUser(LoginRequest request, CancellationToken ct = default);
    Task<User?> GetByEmail(string? email, CancellationToken ct = default);
    Task UpdateHardware(string email, string? hardware = null, CancellationToken ct = default);
    Task UpdateQueueOffsets(string email, UserQueueOffsets queueOffsets, CancellationToken ct = default);
    Task<IEnumerable<User>> GetUsers(string? searchEmail, RoleEnum? searchRole, CancellationToken ct = default);
    Task<string> CheckHardwareHash(User user, string hardware, CancellationToken ct = default);
    Task ChangeRole(string email, RoleEnum newRole, CancellationToken ct = default);
    Task SetEnableStatus(string email, bool isEnabled, CancellationToken ct = default);
    Task RemoveUser(string email, CancellationToken ct = default);
}

public class UserService(IDbFactory dbFactory, ICache cache) : IUserService
{
    public async Task RegisterUser(RegisterUserRequest request, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
        {
            var existingUser = await db.Users.FirstOrDefaultAsync(u => u.Email == request.Email, token: ct);
            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,
                CreatedAt = DateTime.UtcNow,
                IsEnabled = true
            }, token: ct);
        });
    }

    public async Task<User?> GetByEmail(string? email, CancellationToken ct = default)
    {
        if (string.IsNullOrWhiteSpace(email)) throw new ArgumentNullException(nameof(email));

        return await cache.GetFromCacheAsync(User.GetCacheKey(email),
            async () => await dbFactory.Run(async db =>
                await db.Users.FirstOrDefaultAsync(x => x.Email == email, ct)));
    }


    public async Task<User> ValidateUser(LoginRequest request, CancellationToken ct = default) =>
        await dbFactory.Run(async db =>
        {
            var user = await db.Users.FirstOrDefaultAsync(x => x.Email == request.Email, token: ct);
            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, string? hardware = null, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
        {
            await db.Users.UpdateAsync(x => x.Email == email,
                u => new User { Hardware = hardware }, token: ct);
        });
        cache.Invalidate(User.GetCacheKey(email));
    }

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

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

    public async Task<IEnumerable<User>> GetUsers(string? searchEmail, RoleEnum? searchRole, CancellationToken ct) =>
        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: ct));

    public async Task<string> CheckHardwareHash(User user, string hardware, CancellationToken ct = default)
    {
        var requestHWHash = Security.GetHWHash(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, hardware, ct);
            cache.Invalidate(User.GetCacheKey(user.Email));
            await UpdateLastLoginDate(user, ct);
            return requestHWHash;
        }

        var userHWHash = Security.GetHWHash(user.Hardware);
        if (userHWHash != requestHWHash)
            throw new BusinessException(ExceptionEnum.HardwareIdMismatch);
        await UpdateLastLoginDate(user, ct);
        return userHWHash;
    }

    private async Task UpdateLastLoginDate(User user, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
            await db.Users.UpdateAsync(x => x.Email == user.Email, u => new User
            {
                LastLogin = DateTime.UtcNow
            }, ct));
    }

    public async Task ChangeRole(string email, RoleEnum newRole, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
            await db.Users.UpdateAsync(x => x.Email == email, u => new User
            {
                Role = newRole
            }, ct));
    }

    public async Task SetEnableStatus(string email, bool isEnabled, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
            await db.Users.UpdateAsync(x => x.Email == email, u => new User
            {
                IsEnabled = isEnabled
            }, ct));
    }


    public async Task RemoveUser(string email, CancellationToken ct = default)
    {
        await dbFactory.RunAdmin(async db =>
            await db.Users.DeleteAsync(x => x.Email == email, ct));
    }
}