using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using eprintServer.Entities;
using eprintServer.Data; // Assuming your User entity is here

namespace eprintServer.Services;

public class TokenService
{
    private readonly IConfiguration _config;
      private readonly DataContext _context;

    public TokenService(IConfiguration config)
    {
        _config = config;
    }

    public string CreateToken(User user)
    {
        var userRole = user.Role.ToString().Replace("ROLE_", "");

        var claims = new List<Claim>
        {
            new Claim(ClaimTypes.Name, user.Username),
            new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
            new Claim(ClaimTypes.Email, user.Email),
            new Claim(ClaimTypes.Role, userRole)
        };

        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]!));
        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha512Signature);

        var tokenDescriptor = new SecurityTokenDescriptor
        {
            Subject = new ClaimsIdentity(claims),
            Expires = DateTime.Now.AddDays(7),
            SigningCredentials = creds,
            Issuer = _config["Jwt:Issuer"],
            Audience = _config["Jwt:Audience"]
        };

        var tokenHandler = new JwtSecurityTokenHandler();
        var token = tokenHandler.CreateToken(tokenDescriptor);

        return tokenHandler.WriteToken(token);
    }
    public async Task RevokeTokenAsync(string token)
{
    try
    {
        // Option 1: Add to a blacklist/revoked tokens table
        var revokedToken = new RevokedToken
        {
            Token = token,
            RevokedAt = DateTime.UtcNow,
            ExpiresAt = GetTokenExpiration(token) // You'd need to extract expiration from token
        };
        
        await _context.RevokedTokens.AddAsync(revokedToken);
        await _context.SaveChangesAsync();
        
        // Option 2: If you're using a distributed cache
        // await _cache.SetStringAsync($"revoked_token:{token}", "revoked", new DistributedCacheEntryOptions
        // {
        //     AbsoluteExpirationRelativeToNow = TimeSpan.FromDays(7)
        // });
    }
    catch (Exception ex)
    {
        // Log the exception but don't throw - logout should succeed even if token revocation fails
        Console.WriteLine($"Failed to revoke token: {ex.Message}");
    }
}

private DateTime? GetTokenExpiration(string token)
{
    try
    {
        var handler = new System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler();
        var jwtToken = handler.ReadJwtToken(token);
        return jwtToken.ValidTo;
    }
    catch
    {
        return DateTime.UtcNow.AddDays(7); // Default expiration
    }
}
}