using System.Security.Cryptography;
using GameAuthApi.Models;
using MongoDB.Driver;
using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;

namespace GameAuthApi.Services;

public class PasswordResetService
{
    private readonly IMongoCollection<PasswordResetChallenge> _challenges;

    public PasswordResetService(IConfiguration config)
    {
        var client = new MongoClient(config["MongoDB:ConnectionString"]);
        var database = client.GetDatabase(config["MongoDB:DatabaseName"]);
        _challenges = database.GetCollection<PasswordResetChallenge>("PasswordResetChallenges");
    }

    public virtual async Task<string> CreateAsync(string userId)
    {
        await _challenges.UpdateManyAsync(x => x.UserId == userId && !x.Used,
            Builders<PasswordResetChallenge>.Update.Set(x => x.Used, true));
        var code = RandomNumberGenerator.GetInt32(0, 1_000_000).ToString("D6");
        await _challenges.InsertOneAsync(new PasswordResetChallenge
        {
            UserId = userId,
            CodeHash = BCrypt.Net.BCrypt.HashPassword(code),
            CreatedUtc = DateTime.UtcNow,
            ExpiresUtc = DateTime.UtcNow.AddMinutes(15)
        });
        return code;
    }

    public virtual async Task<bool> ConsumeAsync(string userId, string code)
    {
        var challenge = await _challenges.Find(x => x.UserId == userId && !x.Used && x.ExpiresUtc > DateTime.UtcNow)
            .SortByDescending(x => x.CreatedUtc).FirstOrDefaultAsync();
        if (challenge == null || challenge.FailedAttempts >= 5)
            return false;
        if (!BCrypt.Net.BCrypt.Verify(code, challenge.CodeHash))
        {
            await _challenges.UpdateOneAsync(x => x.Id == challenge.Id,
                Builders<PasswordResetChallenge>.Update.Inc(x => x.FailedAttempts, 1));
            return false;
        }
        await _challenges.UpdateOneAsync(x => x.Id == challenge.Id,
            Builders<PasswordResetChallenge>.Update.Set(x => x.Used, true));
        return true;
    }

    public async Task EnsureIndexesAsync() => await _challenges.Indexes.CreateOneAsync(
        new CreateIndexModel<PasswordResetChallenge>(
            Builders<PasswordResetChallenge>.IndexKeys.Ascending(x => x.ExpiresUtc),
            new CreateIndexOptions { ExpireAfter = TimeSpan.Zero, Name = "password_reset_ttl" }));
}