using System.ComponentModel.DataAnnotations;
using DysonNetwork.Sphere.Account;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using NodaTime;
using Microsoft.EntityFrameworkCore;
using System.IdentityModel.Tokens.Jwt;
using System.Text.Json;

namespace DysonNetwork.Sphere.Auth;

[ApiController]
[Route("/auth")]
public class AuthController(
    AppDatabase db,
    AccountService accounts,
    AuthService auth,
    IConfiguration configuration,
    IHttpClientFactory httpClientFactory
) : ControllerBase
{
    public class ChallengeRequest
    {
        [Required] [MaxLength(256)] public string Account { get; set; } = string.Empty;
        [MaxLength(512)] public string? DeviceId { get; set; }
        public List<string> Audiences { get; set; } = new();
        public List<string> Scopes { get; set; } = new();
    }

    [HttpPost("challenge")]
    public async Task<ActionResult<Challenge>> StartChallenge([FromBody] ChallengeRequest request)
    {
        var account = await accounts.LookupAccount(request.Account);
        if (account is null) return NotFound("Account was not found.");

        var ipAddress = HttpContext.Connection.RemoteIpAddress?.ToString();
        var userAgent = HttpContext.Request.Headers.UserAgent.ToString();

        var now = Instant.FromDateTimeUtc(DateTime.UtcNow);

        // Trying to pick up challenges from the same IP address and user agent
        var existingChallenge = await db.AuthChallenges
            .Where(e => e.Account == account)
            .Where(e => e.IpAddress == ipAddress)
            .Where(e => e.UserAgent == userAgent)
            .Where(e => e.StepRemain > 0)
            .Where(e => e.ExpiredAt != null && now < e.ExpiredAt)
            .FirstOrDefaultAsync();
        if (existingChallenge is not null) return existingChallenge;

        var challenge = new Challenge
        {
            Account = account,
            ExpiredAt = Instant.FromDateTimeUtc(DateTime.UtcNow.AddHours(1)),
            StepTotal = 1,
            Audiences = request.Audiences,
            Scopes = request.Scopes,
            IpAddress = ipAddress,
            UserAgent = userAgent,
            DeviceId = request.DeviceId,
        }.Normalize();

        await db.AuthChallenges.AddAsync(challenge);
        await db.SaveChangesAsync();
        return challenge;
    }

    [HttpGet("challenge/{id}/factors")]
    public async Task<ActionResult<List<AccountAuthFactor>>> GetChallengeFactors([FromRoute] Guid id)
    {
        var challenge = await db.AuthChallenges
            .Include(e => e.Account)
            .Include(e => e.Account.AuthFactors)
            .Where(e => e.Id == id).FirstOrDefaultAsync();
        return challenge is null
            ? NotFound("Auth challenge was not found.")
            : challenge.Account.AuthFactors.ToList();
    }

    [HttpPost("challenge/{id}/factors/{factorId:long}")]
    public async Task<ActionResult> RequestFactorCode([FromRoute] Guid id, [FromRoute] long factorId)
    {
        var challenge = await db.AuthChallenges
            .Include(e => e.Account)
            .Where(e => e.Id == id).FirstOrDefaultAsync();
        if (challenge is null) return NotFound("Auth challenge was not found.");
        var factor = await db.AccountAuthFactors
            .Where(e => e.Id == factorId)
            .Where(e => e.Account == challenge.Account).FirstOrDefaultAsync();
        if (factor is null) return NotFound("Auth factor was not found.");

        // TODO do the logic here

        return Ok();
    }

    public class PerformChallengeRequest
    {
        [Required] public long FactorId { get; set; }
        [Required] public string Password { get; set; } = string.Empty;
    }

    [HttpPatch("challenge/{id}")]
    public async Task<ActionResult<Challenge>> DoChallenge(
        [FromRoute] Guid id,
        [FromBody] PerformChallengeRequest request
    )
    {
        var challenge = await db.AuthChallenges.FindAsync(id);
        if (challenge is null) return NotFound("Auth challenge was not found.");

        var factor = await db.AccountAuthFactors.FindAsync(request.FactorId);
        if (factor is null) return NotFound("Auth factor was not found.");

        if (challenge.StepRemain == 0) return challenge;
        if (challenge.ExpiredAt.HasValue && challenge.ExpiredAt.Value < Instant.FromDateTimeUtc(DateTime.UtcNow))
            return BadRequest();

        try
        {
            if (factor.VerifyPassword(request.Password))
            {
                challenge.StepRemain--;
                challenge.BlacklistFactors.Add(factor.Id);
            }
        }
        catch
        {
            return BadRequest();
        }

        await db.SaveChangesAsync();
        return challenge;
    }

    public class TokenExchangeRequest
    {
        public string GrantType { get; set; } = string.Empty;
        public string? RefreshToken { get; set; }
        public string? Code { get; set; }
    }

    [HttpPost("token")]
    public async Task<ActionResult<SignedTokenPair>> ExchangeToken([FromBody] TokenExchangeRequest request)
    {
        Session? session;
        switch (request.GrantType)
        {
            case "authorization_code":
                var code = Guid.TryParse(request.Code, out var codeId) ? codeId : Guid.Empty;
                if (code == Guid.Empty)
                    return BadRequest("Invalid or missing authorization code.");
                var challenge = await db.AuthChallenges
                    .Include(e => e.Account)
                    .Where(e => e.Id == code)
                    .FirstOrDefaultAsync();
                if (challenge is null)
                    return BadRequest("Authorization code not found or expired.");
                if (challenge.StepRemain != 0)
                    return BadRequest("Challenge not yet completed.");

                session = await db.AuthSessions
                    .Where(e => e.Challenge == challenge)
                    .FirstOrDefaultAsync();
                if (session is not null)
                    return BadRequest("Session already exists for this challenge.");

                session = new Session
                {
                    LastGrantedAt = Instant.FromDateTimeUtc(DateTime.UtcNow),
                    ExpiredAt = Instant.FromDateTimeUtc(DateTime.UtcNow.AddDays(30)),
                    Account = challenge.Account,
                    Challenge = challenge,
                };

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

                return auth.CreateToken(session);
            case "refresh_token":
                var handler = new JwtSecurityTokenHandler();
                var token = handler.ReadJwtToken(request.RefreshToken);
                var sessionIdClaim = token.Claims.FirstOrDefault(c => c.Type == "session_id")?.Value;

                if (!Guid.TryParse(sessionIdClaim, out var sessionId))
                    return Unauthorized("Invalid or missing session_id claim in refresh token.");

                session = await db.AuthSessions
                    .Include(e => e.Account)
                    .Include(e => e.Challenge)
                    .FirstOrDefaultAsync(s => s.Id == sessionId);
                if (session is null)
                    return NotFound("Session not found or expired.");

                session.LastGrantedAt = Instant.FromDateTimeUtc(DateTime.UtcNow);
                await db.SaveChangesAsync();

                return auth.CreateToken(session);
            default:
                return BadRequest("Unsupported grant type.");
        }
    }

    [Authorize]
    [HttpGet("test")]
    public async Task<ActionResult> Test()
    {
        var sessionIdClaim = HttpContext.User.FindFirst("session_id")?.Value;
        if (!Guid.TryParse(sessionIdClaim, out var sessionId))
            return Unauthorized();

        var session = await db.AuthSessions.FirstOrDefaultAsync(s => s.Id == sessionId);
        if (session is null) return NotFound();

        return Ok(session);
    }

    [HttpPost("captcha")]
    public async Task<ActionResult> ValidateCaptcha([FromBody] string token)
    {
        var provider = configuration.GetSection("Captcha")["Provider"]?.ToLower();
        var apiKey = configuration.GetSection("Captcha")["ApiKey"];
        var apiSecret = configuration.GetSection("Captcha")["ApiSecret"];

        var client = httpClientFactory.CreateClient();

        switch (provider)
        {
            case "cloudflare":
                var content = new StringContent($"secret={apiSecret}&response={token}", System.Text.Encoding.UTF8,
                    "application/x-www-form-urlencoded");
                var response = await client.PostAsync("https://challenges.cloudflare.com/turnstile/v0/siteverify",
                    content);
                response.EnsureSuccessStatusCode();

                var json = await response.Content.ReadAsStringAsync();
                var cfResult = JsonSerializer.Deserialize<CloudflareVerificationResponse>(json);

                if (cfResult?.Success == true)
                    return Ok(new { success = true });

                return BadRequest(new { success = false, errors = cfResult?.ErrorCodes });
            case "google":
                var secretKey = configuration.GetSection("CaptchaSettings")["GoogleRecaptchaSecretKey"];
                if (string.IsNullOrEmpty(secretKey))
                {
                    return StatusCode(500, "Google reCaptcha secret key is not configured.");
                }

                content = new StringContent($"secret={secretKey}&response={token}", System.Text.Encoding.UTF8,
                    "application/x-www-form-urlencoded");
                response = await client.PostAsync("https://www.google.com/recaptcha/api/siteverify", content);
                response.EnsureSuccessStatusCode();

                json = await response.Content.ReadAsStringAsync();
                var capResult = JsonSerializer.Deserialize<GoogleVerificationResponse>(json);

                if (capResult?.Success == true)
                    return Ok(new { success = true });

                return BadRequest(new { success = false, errors = capResult?.ErrorCodes });
            default:
                return StatusCode(500, "The server misconfigured for the captcha.");
        }
    }
}