using DysonNetwork.Sphere.Auth.Proto;
using Grpc.Core;
using Google.Protobuf.WellKnownTypes;
using DysonNetwork.Sphere.Account;
using Microsoft.EntityFrameworkCore;
using NodaTime;
using System.Text.Json;
using DysonNetwork.Shared.Models;
using Challenge = DysonNetwork.Sphere.Auth.Proto.Challenge;
using Session = DysonNetwork.Sphere.Auth.Proto.Session;

namespace DysonNetwork.Sphere.Auth;

public class AuthGrpcService : DysonNetwork.Sphere.Auth.Proto.AuthService.AuthServiceBase
{
    private readonly AppDatabase _db;
    private readonly AccountService _accounts;
    private readonly AuthService _auth;

    public AuthGrpcService(AppDatabase db, AccountService accounts, AuthService auth)
    {
        _db = db;
        _accounts = accounts;
        _auth = auth;
    }

    public override async Task<LoginResponse> Login(LoginRequest request, ServerCallContext context)
    {
        var account = await _accounts.LookupAccount(request.Username);
        if (account == null)
        {
            throw new RpcException(new Grpc.Core.Status(StatusCode.NotFound, "Account not found."));
        }

        var factor = await _db.AccountAuthFactors.FirstOrDefaultAsync(f => f.AccountId == account.Id && f.Type == AccountAuthFactorType.Password);
        if (factor == null || !factor.VerifyPassword(request.Password))
        {
            throw new RpcException(new Grpc.Core.Status(StatusCode.Unauthenticated, "Invalid credentials."));
        }

        var session = new Session
        {
            LastGrantedAt = Instant.FromDateTimeUtc(DateTime.UtcNow),
            ExpiredAt = Instant.FromDateTimeUtc(DateTime.UtcNow.AddDays(30)),
            Account = account,
            Challenge = new Challenge() // Create a dummy challenge
        };

        _db.AuthSessions.Add(session);
        await _db.SaveChangesAsync();

        var token = _auth.CreateToken(session);

        return new LoginResponse
        {
            AccessToken = token,
            ExpiresIn = (long)(session.ExpiredAt.Value - session.LastGrantedAt.Value).TotalSeconds
        };
    }

    public override async Task<IntrospectionResponse> IntrospectToken(IntrospectTokenRequest request, ServerCallContext context)
    {
        if (_auth.ValidateToken(request.Token, out var sessionId))
        {
            var session = await _db.AuthSessions
                .Include(s => s.Account)
                .Include(s => s.Challenge)
                .FirstOrDefaultAsync(s => s.Id == sessionId);

            if (session != null)
            {
                return new IntrospectionResponse
                {
                    Active = true,
                    Claims = JsonSerializer.Serialize(new { sub = session.AccountId }),
                    ClientId = session.AppId?.ToString() ?? "",
                    Username = session.Account.Name,
                    Scope = string.Join(" ", session.Challenge.Scopes),
                    Iat = Timestamp.FromDateTime(session.CreatedAt.ToDateTimeUtc()),
                    Exp = Timestamp.FromDateTime(session.ExpiredAt?.ToDateTimeUtc() ?? DateTime.MaxValue)
                };
            }
        }

        return new IntrospectionResponse { Active = false };
    }

    public override async Task<Empty> Logout(Empty request, ServerCallContext context)
    {
        var authorizationHeader = context.RequestHeaders.FirstOrDefault(h => h.Key == "authorization");
        if (authorizationHeader != null)
        {
            var token = authorizationHeader.Value.Replace("Bearer ", "");
            if (_auth.ValidateToken(token, out var sessionId))
            {
                var session = await _db.AuthSessions.FindAsync(sessionId);
                if (session != null)
                {
                    _db.AuthSessions.Remove(session);
                    await _db.SaveChangesAsync();
                }
            }
        }
        return new Empty();
    }
}