using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.SelfService.Portal.Core.API.Context;
using Microsoft.SelfService.Portal.Core.API.Dto.Auth;
using Microsoft.SelfService.Portal.Core.API.Models;
using Microsoft.SelfService.Portal.Core.API.Services;
using System.Text.Json;

namespace Microsoft.SelfService.Portal.Core.API.Controllers
{
    [Route("api/auth")]
    [ApiController]
    public class AuthController : Controller
    {
        private readonly DataContext _context;
        private readonly ApiTokenService _tokenService;

        public AuthController(DataContext context, ApiTokenService tokenService)
        {
            _context = context;
            _tokenService = tokenService;
        }

        [HttpPost("token")]
        [AllowAnonymous]
        [ProducesResponseType(200, Type = typeof(TokenResponseDto))]
        [ProducesResponseType(400)]
        [ProducesResponseType(401)]
        public IActionResult CreateToken([FromBody] TokenRequestDto request)
        {
            if (request == null
                || string.IsNullOrWhiteSpace(request.ClientId)
                || string.IsNullOrWhiteSpace(request.ClientSecret))
            {
                return BadRequest(new { message = "ClientId and ClientSecret are required." });
            }

            var client = _context.ApiClients
                .FirstOrDefault(existing => existing.ClientId == request.ClientId);

            if (client == null
                || !client.IsEnabled
                || (client.ExpiresAt.HasValue && client.ExpiresAt.Value <= DateTime.UtcNow)
                || !ApiClientSecretHasher.VerifySecret(request.ClientSecret, client.SecretHash))
            {
                return Unauthorized(new { message = "Invalid client credentials." });
            }

            IReadOnlyCollection<string> scopes;
            try
            {
                scopes = _tokenService.ResolveRequestedScopes(client, request.Scope);
            }
            catch (InvalidOperationException ex)
            {
                return Unauthorized(new { message = ex.Message });
            }

            var token = _tokenService.CreateAccessToken(client, scopes);
            var now = DateTime.UtcNow;

            client.LastUsedAt = now;
            client.Modified = now;
            client.ModifiedBy = client.ClientId;

            _context.ApiTokens.Add(new ApiTokenModel
            {
                Id = Guid.NewGuid(),
                Jti = token.Jti,
                Subject = client.ClientId,
                SubjectType = "ApiClient",
                ApiClientId = client.Id,
                Name = $"Client credentials token for {client.Name}",
                ScopesJson = JsonSerializer.Serialize(scopes),
                IssuedAt = token.IssuedAt,
                ExpiresAt = token.ExpiresAt,
                Created = now,
                CreatedBy = client.ClientId,
                Modified = now,
                ModifiedBy = client.ClientId
            });

            _context.SaveChanges();

            return Ok(new TokenResponseDto
            {
                AccessToken = token.AccessToken,
                ExpiresIn = _tokenService.TokenLifetimeSeconds,
                Scope = string.Join(' ', scopes)
            });
        }
    }
}