// AK-P14a · P14 Email — sending-domain settings service.
//
// Backs the Sende-Domain screen: read the tenant's sending domain (+ its
// BCC-logging inbound address), add a domain (registers it with Mailjet and
// stores the DKIM/SPF records the tenant must publish), and toggle BCC logging.
// The 5-minute worker probe (email-domain-probe-cron) drives the verification
// status; this service never blocks on DNS.
//
// Every tenant DB op runs inside withTenantRLS() so the policy binds at the P5
// cutover. The Mailjet provisioner is the EU SMTP abstraction (AD-6); it is
// optional at runtime — without credentials the domain row is still created
// (status pending) and the cron verifies DNS independently.

import { createMailjetDnsProvisioner, type MailjetDnsProvisioner } from "@hivegrid/mail";
import { CatalogError, foundationErrors } from "@hivegrid/foundation";
import { featureKeys } from "@hivegrid/entitlements";
import { requireAuth } from "~/utils/loaders.middleware";
import { getTenantIdFromUrl } from "~/utils/services/.server/urlService";
import { getUserInfo } from "~/utils/session.server";
import { getPermissionsByUser } from "~/utils/db/permissions/userRoles.db.server";
import { withTenantRLS } from "~/utils/db/.server/tenantRls.server";
import { requireTenantProductAccess } from "~/utils/entitlements/.server/productAccess.server";

const BCC_LOCAL_PART = "crm";
const BCC_INBOUND_HOST = "bcc.hivegrid.de";
const DEFAULT_DMARC_RECORD = "v=DMARC1; p=none";

const DOMAIN_PATTERN = /^(?=.{1,253}$)([a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z]{2,}$/;

export type EmailDomainContext = {
  tenantId: string;
  userId: string;
  permissions: readonly string[];
};

export async function loadEmailDomainContext({ request, params }: { request: Request; params: Record<string, string | undefined> }): Promise<EmailDomainContext> {
  await requireAuth({ request, params });
  const [tenantId, userInfo] = await Promise.all([getTenantIdFromUrl(params), getUserInfo(request)]);
  if (!tenantId || !userInfo.userId) {
    throw new CatalogError(foundationErrors.notFound);
  }
  // Child resource routes can be called directly without executing their
  // layout loader. Enforce the paid add-on and billing status at the shared
  // context boundary every email-marketing route already uses.
  await requireTenantProductAccess({ request, params, featureKey: featureKeys.emailMarketing });
  const permissions = await getPermissionsByUser(userInfo.userId, tenantId);
  return { tenantId, userId: userInfo.userId, permissions };
}

export function emailDomainCanView(ctx: EmailDomainContext): boolean {
  return ctx.permissions.includes("email.domain.view") || ctx.permissions.includes("email.domain.manage");
}

export function emailDomainCanManage(ctx: EmailDomainContext): boolean {
  return ctx.permissions.includes("email.domain.manage");
}

/** Permission-denied surfaces as 404, never 403 (Bauprinzip A.5.3). */
export function notFoundResponse(): Response {
  return new Response("Not Found", { status: 404 });
}

export function badRequestResponse(): Response {
  return new Response("Bad Request", { status: 400 });
}

/** Pure: normalize + validate a domain input. Returns null when invalid. */
export function normalizeDomainInput(raw: string): string | null {
  const domain = raw.trim().toLowerCase().replace(/\.$/, "");
  return DOMAIN_PATTERN.test(domain) ? domain : null;
}

/** Deterministic, display-only BCC address for a tenant. */
export function bccAddressFor(tenantSlug: string): string {
  const safeSlug = tenantSlug.trim().toLowerCase().replace(/[^a-z0-9-]/g, "") || "tenant";
  return `${BCC_LOCAL_PART}.${safeSlug}@${BCC_INBOUND_HOST}`;
}

function envProvisioner(): MailjetDnsProvisioner | null {
  const apiKey = process.env.MAILJET_API_KEY;
  const secretKey = process.env.MAILJET_SECRET_KEY;
  if (!apiKey || !secretKey) {
    return null;
  }
  return createMailjetDnsProvisioner({ apiKey, secretKey });
}

export type SendingDomainStateRow = {
  id: string;
  domain: string;
  status: "pending" | "verifying" | "verified" | "failed";
  dkimSelector: string | null;
  dkimRecord: string | null;
  spfRecord: string | null;
  dmarcRecord: string | null;
  lastError: string | null;
};

export async function getSendingDomainState(tenantId: string): Promise<{ domain: SendingDomainStateRow | null; bccEnabled: boolean }> {
  return withTenantRLS(tenantId, async (tx) => {
    const row = await tx.tenantSendingDomain.findFirst({ where: { tenantId, archivedAt: null }, orderBy: { createdAt: "desc" } });
    const bcc = await tx.tenantInboundAddress.findFirst({ where: { tenantId, purpose: "bcc_logging", archivedAt: null } });
    const domain: SendingDomainStateRow | null = row
      ? {
          id: row.id,
          domain: row.domain,
          status: row.verificationStatus,
          dkimSelector: row.dkimSelector,
          dkimRecord: row.dkimRecord,
          spfRecord: row.spfRecord,
          dmarcRecord: row.dmarcRecord,
          lastError: row.lastError,
        }
      : null;
    return { domain, bccEnabled: bcc?.enabled ?? false };
  });
}

/**
 * Add (or replace) the tenant sending domain. Registers it with Mailjet and
 * stores the published DKIM/SPF records; falls back to a record-less pending row
 * when Mailjet credentials are absent. Soft-archives any prior domain.
 */
export async function createSendingDomain(
  tenantId: string,
  domain: string,
  now: Date = new Date(),
  deps: { provisioner?: MailjetDnsProvisioner | null } = {},
): Promise<{ id: string }> {
  const provisioner = deps.provisioner === undefined ? envProvisioner() : deps.provisioner;
  let dkimSelector: string | null = null;
  let dkimRecord: string | null = null;
  let spfRecord: string | null = null;
  let mailjetDnsId: string | null = null;
  if (provisioner) {
    await provisioner.registerDomain(domain).catch(() => undefined);
    const records = await provisioner.getRecords(domain).catch(() => null);
    if (records) {
      dkimSelector = records.dkimSelector;
      dkimRecord = records.dkimRecord;
      spfRecord = records.spfRecord;
      mailjetDnsId = records.dnsId;
    }
  }
  return withTenantRLS(tenantId, async (tx) => {
    await tx.tenantSendingDomain.updateMany({ where: { tenantId, archivedAt: null }, data: { archivedAt: now } });
    const created = await tx.tenantSendingDomain.create({
      data: {
        tenantId,
        domain,
        dkimSelector,
        dkimRecord,
        spfRecord,
        dmarcRecord: DEFAULT_DMARC_RECORD,
        mailjetDnsId,
        verificationStatus: "pending",
        firstProbeAt: now,
      },
      select: { id: true },
    });
    return created;
  });
}

/** Enable/disable BCC logging by upserting the tenant bcc_logging inbound address. */
export async function setBccLogging(tenantId: string, tenantSlug: string, enabled: boolean): Promise<void> {
  const address = bccAddressFor(tenantSlug);
  await withTenantRLS(tenantId, async (tx) => {
    const existing = await tx.tenantInboundAddress.findFirst({ where: { tenantId, purpose: "bcc_logging" } });
    if (existing) {
      await tx.tenantInboundAddress.update({ where: { id: existing.id }, data: { enabled, archivedAt: null } });
      return;
    }
    await tx.tenantInboundAddress.create({
      data: { tenantId, address, fullAddress: address, localPart: BCC_LOCAL_PART, purpose: "bcc_logging", enabled },
    });
  });
}