using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using line_gestao_api.Dtos;
using line_gestao_api.Models;
using line_gestao_api.Services;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;

namespace line_gestao_api.Controllers;

[ApiController]
[Route("auth")]
public class AuthController : ControllerBase
{
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly ITenantProvider _tenantProvider;
    private readonly IConfiguration _config;

    public AuthController(
        UserManager<ApplicationUser> userManager,
        ITenantProvider tenantProvider,
        IConfiguration config)
    {
        _userManager = userManager;
        _tenantProvider = tenantProvider;
        _config = config;
    }

    [HttpPost("register")]
    [Authorize(Roles = "admin")]
    public async Task<IActionResult> Register(RegisterRequest req)
    {
        if (req.Password != req.ConfirmPassword)
            return BadRequest("As senhas não conferem.");

        var tenantId = _tenantProvider.TenantId;
        if (tenantId == null)
            return Unauthorized("Tenant inválido.");

        var email = req.Email.Trim().ToLowerInvariant();
        var normalizedEmail = _userManager.NormalizeEmail(email);

        var exists = await _userManager.Users
            .AnyAsync(u => u.NormalizedEmail == normalizedEmail && u.TenantId == tenantId);

        if (exists) return BadRequest("E-mail já cadastrado.");

        var user = new ApplicationUser
        {
            Name = req.Name.Trim(),
            Email = email,
            UserName = email,
            TenantId = tenantId.Value,
            IsActive = true,
            EmailConfirmed = true
        };

        var createResult = await _userManager.CreateAsync(user, req.Password);
        if (!createResult.Succeeded)
            return BadRequest(createResult.Errors.Select(e => e.Description).ToList());

        await _userManager.AddToRoleAsync(user, "leitura");

        var token = await GenerateJwtAsync(user);
        return Ok(new AuthResponse(token));
    }

    [HttpPost("login")]
    public async Task<IActionResult> Login(LoginRequest req)
    {
        var email = (req.Email ?? "").Trim().ToLowerInvariant();
        var password = req.Password ?? "";
        var normalizedEmail = _userManager.NormalizeEmail(email);

        var tenantId = ResolveTenantId(req);
        ApplicationUser? user;

        if (tenantId == null)
        {
            var users = await _userManager.Users
                .IgnoreQueryFilters()
                .Where(u => u.NormalizedEmail == normalizedEmail)
                .ToListAsync();

            if (users.Count == 0)
                return Unauthorized("Credenciais inválidas.");

            if (users.Count > 1)
                return BadRequest("Informe o tenant para realizar o login.");

            user = users[0];
        }
        else
        {
            user = await _userManager.Users
                .IgnoreQueryFilters()
                .FirstOrDefaultAsync(u => u.NormalizedEmail == normalizedEmail && u.TenantId == tenantId);
        }

        if (user == null)
            return Unauthorized("Credenciais inválidas.");

        if (!user.IsActive)
            return Unauthorized("Usuário desativado.");

        var valid = await _userManager.CheckPasswordAsync(user, password);
        if (!valid)
            return Unauthorized("Credenciais inválidas.");

        var token = await GenerateJwtAsync(user);
        return Ok(new AuthResponse(token));
    }

    private Guid? ResolveTenantId(LoginRequest req)
    {
        if (req.TenantId.HasValue)
            return req.TenantId.Value;

        var headerValue = Request.Headers["X-Tenant-Id"].FirstOrDefault();
        return Guid.TryParse(headerValue, out var parsed) ? parsed : null;
    }

    private async Task<string> GenerateJwtAsync(ApplicationUser user)
    {
        var key = _config["Jwt:Key"]!;
        var issuer = _config["Jwt:Issuer"]!;
        var audience = _config["Jwt:Audience"]!;
        var expiresMinutes = int.Parse(_config["Jwt:ExpiresMinutes"]!);

        var roles = await _userManager.GetRolesAsync(user);

        var claims = new List<Claim>
        {
            new(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
            new(JwtRegisteredClaimNames.Email, user.Email ?? string.Empty),
            new("name", user.Name),
            new("tenantId", user.TenantId.ToString())
        };

        claims.AddRange(roles.Select(r => new Claim(ClaimTypes.Role, r)));

        var signingKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(key));
        var creds = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256);

        var token = new JwtSecurityToken(
            issuer: issuer,
            audience: audience,
            claims: claims,
            expires: DateTime.UtcNow.AddMinutes(expiresMinutes),
            signingCredentials: creds
        );

        return new JwtSecurityTokenHandler().WriteToken(token);
    }
}