using line_gestao_api.Data;
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;

namespace line_gestao_api.Controllers;

[ApiController]
[Route("api/system/tenants/{tenantId:guid}/users")]
[Authorize(Policy = "SystemAdmin")]
public class SystemTenantUsersController : ControllerBase
{
    private readonly AppDbContext _db;
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly RoleManager<IdentityRole<Guid>> _roleManager;
    private readonly ISystemAuditService _systemAuditService;

    public SystemTenantUsersController(
        AppDbContext db,
        UserManager<ApplicationUser> userManager,
        RoleManager<IdentityRole<Guid>> roleManager,
        ISystemAuditService systemAuditService)
    {
        _db = db;
        _userManager = userManager;
        _roleManager = roleManager;
        _systemAuditService = systemAuditService;
    }

    [HttpPost]
    public async Task<ActionResult<SystemTenantUserCreatedDto>> CreateUserForTenant(
        [FromRoute] Guid tenantId,
        [FromBody] CreateSystemTenantUserRequest request)
    {
        if (tenantId == Guid.Empty)
        {
            return await RejectAsync(tenantId, StatusCodes.Status400BadRequest, "TenantId inválido.", "invalid_tenant_id");
        }

        var tenant = await _db.Tenants.AsNoTracking().FirstOrDefaultAsync(t => t.Id == tenantId);
        if (tenant == null)
        {
            return await RejectAsync(tenantId, StatusCodes.Status404NotFound, "Tenant não encontrado.", "tenant_not_found");
        }

        if (string.IsNullOrWhiteSpace(request.Email))
        {
            return await RejectAsync(tenantId, StatusCodes.Status400BadRequest, "Email é obrigatório.", "missing_email");
        }

        if (string.IsNullOrWhiteSpace(request.Password))
        {
            return await RejectAsync(tenantId, StatusCodes.Status400BadRequest, "Password é obrigatória.", "missing_password");
        }

        if (request.Roles == null || request.Roles.Count == 0)
        {
            return await RejectAsync(tenantId, StatusCodes.Status400BadRequest, "Informe ao menos uma role.", "missing_roles");
        }

        var normalizedRoles = request.Roles
            .Where(r => !string.IsNullOrWhiteSpace(r))
            .Select(r => r.Trim().ToLowerInvariant())
            .Distinct(StringComparer.OrdinalIgnoreCase)
            .ToList();

        if (normalizedRoles.Count == 0)
        {
            return await RejectAsync(tenantId, StatusCodes.Status400BadRequest, "Roles inválidas.", "invalid_roles");
        }

        var unsupportedRoles = normalizedRoles
            .Where(role => !AppRoles.All.Contains(role, StringComparer.OrdinalIgnoreCase))
            .ToList();
        if (unsupportedRoles.Count > 0)
        {
            return await RejectAsync(
                tenantId,
                StatusCodes.Status400BadRequest,
                $"Roles não suportadas: {string.Join(", ", unsupportedRoles)}. Use apenas: {string.Join(", ", AppRoles.All)}.",
                "unsupported_roles");
        }

        if (!tenant.IsSystem && normalizedRoles.Contains(SystemTenantConstants.SystemRole))
        {
            return await RejectAsync(
                tenantId,
                StatusCodes.Status400BadRequest,
                "A role sysadmin só pode ser usada no SystemTenant.",
                "invalid_sysadmin_outside_system_tenant");
        }

        if (tenant.IsSystem && normalizedRoles.Any(r => r != SystemTenantConstants.SystemRole))
        {
            return await RejectAsync(
                tenantId,
                StatusCodes.Status400BadRequest,
                "No SystemTenant é permitido apenas a role sysadmin.",
                "invalid_non_system_role_for_system_tenant");
        }

        foreach (var role in normalizedRoles)
        {
            if (!await _roleManager.RoleExistsAsync(role))
            {
                return await RejectAsync(
                    tenantId,
                    StatusCodes.Status400BadRequest,
                    $"Role inexistente: {role}",
                    "role_not_found");
            }
        }

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

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

        if (alreadyExists)
        {
            return await RejectAsync(tenantId, StatusCodes.Status409Conflict, "Já existe usuário com este email neste tenant.", "email_exists");
        }

        var name = string.IsNullOrWhiteSpace(request.Name)
            ? email
            : request.Name.Trim();

        var user = new ApplicationUser
        {
            Name = name,
            Email = email,
            UserName = email,
            TenantId = tenantId,
            EmailConfirmed = true,
            IsActive = true,
            LockoutEnabled = true
        };

        IdentityResult createResult;
        try
        {
            createResult = await _userManager.CreateAsync(user, request.Password);
        }
        catch (DbUpdateException)
        {
            return await RejectAsync(
                tenantId,
                StatusCodes.Status409Conflict,
                "Não foi possível criar usuário. Email/username já em uso.",
                "db_conflict");
        }

        if (!createResult.Succeeded)
        {
            await _systemAuditService.LogAsync(
                action: SystemAuditActions.CreateTenantUserRejected,
                targetTenantId: tenantId,
                metadata: new
                {
                    reason = "identity_create_failed",
                    email,
                    errors = createResult.Errors.Select(e => e.Description).ToList()
                });

            return BadRequest(createResult.Errors.Select(e => e.Description).ToList());
        }

        var addRolesResult = await _userManager.AddToRolesAsync(user, normalizedRoles);
        if (!addRolesResult.Succeeded)
        {
            await _userManager.DeleteAsync(user);
            await _systemAuditService.LogAsync(
                action: SystemAuditActions.CreateTenantUserRejected,
                targetTenantId: tenantId,
                metadata: new
                {
                    reason = "identity_add_roles_failed",
                    email,
                    roles = normalizedRoles,
                    errors = addRolesResult.Errors.Select(e => e.Description).ToList()
                });

            return BadRequest(addRolesResult.Errors.Select(e => e.Description).ToList());
        }

        await _systemAuditService.LogAsync(
            action: SystemAuditActions.CreateTenantUser,
            targetTenantId: tenantId,
            metadata: new
            {
                createdUserId = user.Id,
                email,
                roles = normalizedRoles
            });

        var response = new SystemTenantUserCreatedDto
        {
            UserId = user.Id,
            TenantId = tenantId,
            Email = email,
            Roles = normalizedRoles
        };

        return StatusCode(StatusCodes.Status201Created, response);
    }

    private async Task<ActionResult<SystemTenantUserCreatedDto>> RejectAsync(
        Guid targetTenantId,
        int statusCode,
        string message,
        string reason)
    {
        await _systemAuditService.LogAsync(
            action: SystemAuditActions.CreateTenantUserRejected,
            targetTenantId: targetTenantId,
            metadata: new { reason, message });

        return StatusCode(statusCode, message);
    }
}