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;
using System.Globalization;
using System.Text;

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 (request.ClientCredentialsOnly)
        {
            if (tenant.IsSystem)
            {
                return await RejectAsync(
                    tenantId,
                    StatusCodes.Status400BadRequest,
                    "Credenciais de cliente não podem ser criadas no SystemTenant.",
                    "invalid_client_credentials_on_system_tenant");
            }

            if (normalizedRoles.Count != 1 || !normalizedRoles.Contains(AppRoles.Cliente, StringComparer.OrdinalIgnoreCase))
            {
                return await RejectAsync(
                    tenantId,
                    StatusCodes.Status400BadRequest,
                    "Neste fluxo, somente a role cliente é permitida.",
                    "invalid_roles_for_client_credentials_flow");
            }
        }

        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());
        }

        var linesReassigned = 0;
        if (request.ClientCredentialsOnly)
        {
            linesReassigned = await RebindMobileLinesToTenantBySourceKeyAsync(tenant);
        }

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

        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);
    }

    private async Task<int> RebindMobileLinesToTenantBySourceKeyAsync(Tenant tenant)
    {
        if (tenant.Id == Guid.Empty)
        {
            return 0;
        }

        if (!string.Equals(
                tenant.SourceType,
                SystemTenantConstants.MobileLinesClienteSourceType,
                StringComparison.OrdinalIgnoreCase))
        {
            return 0;
        }

        var normalizedKeys = new HashSet<string>(StringComparer.Ordinal);
        AddNormalizedTenantKey(normalizedKeys, tenant.SourceKey);
        AddNormalizedTenantKey(normalizedKeys, tenant.NomeOficial);

        if (normalizedKeys.Count == 0)
        {
            return 0;
        }

        var candidates = await _db.MobileLines
            .IgnoreQueryFilters()
            .Where(x => x.TenantId != tenant.Id)
            .Where(x => x.Cliente != null && x.Cliente != string.Empty)
            .ToListAsync();

        if (candidates.Count == 0)
        {
            return 0;
        }

        var hasAnyTenantLine = await _db.MobileLines
            .IgnoreQueryFilters()
            .AsNoTracking()
            .AnyAsync(x => x.TenantId == tenant.Id);

        var now = DateTime.UtcNow;
        var reassigned = ReassignByMatcher(
            candidates,
            normalizedKeys,
            tenant.Id,
            now,
            isRelaxedMatch: false);

        if (reassigned == 0 && !hasAnyTenantLine)
        {
            reassigned = ReassignByMatcher(
                candidates,
                normalizedKeys,
                tenant.Id,
                now,
                isRelaxedMatch: true);
        }

        if (reassigned > 0)
        {
            await _db.SaveChangesAsync();
        }

        return reassigned;
    }

    private static int ReassignByMatcher(
        IReadOnlyList<MobileLine> candidates,
        IReadOnlyCollection<string> normalizedKeys,
        Guid tenantId,
        DateTime now,
        bool isRelaxedMatch)
    {
        if (normalizedKeys.Count == 0)
        {
            return 0;
        }

        var keys = isRelaxedMatch
            ? normalizedKeys.Where(k => k.Length >= 6).ToList()
            : normalizedKeys.ToList();

        if (keys.Count == 0)
        {
            return 0;
        }

        var reassigned = 0;

        foreach (var line in candidates)
        {
            var normalizedClient = NormalizeTenantKey(line.Cliente ?? string.Empty);
            if (string.IsNullOrWhiteSpace(normalizedClient) ||
                string.Equals(normalizedClient, "RESERVA", StringComparison.Ordinal))
            {
                continue;
            }

            var matches = !isRelaxedMatch
                ? keys.Contains(normalizedClient, StringComparer.Ordinal)
                : keys.Any(k =>
                    normalizedClient.Contains(k, StringComparison.Ordinal) ||
                    k.Contains(normalizedClient, StringComparison.Ordinal));

            if (!matches)
            {
                continue;
            }

            line.TenantId = tenantId;
            line.UpdatedAt = now;
            reassigned++;
        }

        return reassigned;
    }

    private static void AddNormalizedTenantKey(ISet<string> keys, string? rawKey)
    {
        var normalized = NormalizeTenantKey(rawKey ?? string.Empty);
        if (string.IsNullOrWhiteSpace(normalized))
        {
            return;
        }

        if (string.Equals(normalized, "RESERVA", StringComparison.Ordinal))
        {
            return;
        }

        keys.Add(normalized);
    }

    private static string NormalizeTenantKey(string value)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return string.Empty;
        }

        var normalized = value.Trim().Normalize(NormalizationForm.FormD);
        var sb = new StringBuilder(normalized.Length);
        var previousWasSpace = false;
        foreach (var ch in normalized)
        {
            var category = CharUnicodeInfo.GetUnicodeCategory(ch);
            if (category == UnicodeCategory.NonSpacingMark)
            {
                continue;
            }

            if (char.IsWhiteSpace(ch))
            {
                if (!previousWasSpace)
                {
                    sb.Append(' ');
                    previousWasSpace = true;
                }
                continue;
            }

            sb.Append(char.ToUpperInvariant(ch));
            previousWasSpace = false;
        }

        return sb.ToString().Trim();
    }
}