import type { Database } from "@db/sqlite";
import { generateSecurePassword, hashPassword } from "./crypto.ts";
import { lastInsertId as appLastId } from "./db.ts";
import {
  lastInsertId as platformLastId,
  listTenants as listTenantsRaw,
  tenantByCode,
  tenantById,
  type PlatformDb,
} from "./platform_db.ts";
import { companyByCode, normCompanyCode, normalizeCompanyProfile, validateCompanyProfile, type CompanyProfileInput } from "./companies.ts";
import { accessEmailBody, sendMail } from "./mail.ts";
import { config } from "./config.ts";

export type CreateTenantInput = CompanyProfileInput & {
  admin_username?: string;
  admin_display_name?: string;
  contact_email?: string;
  contact_name?: string;
  plan?: string;
  valid_until?: string | null;
  notes?: string;
  send_email?: boolean;
};

export type UpdateTenantInput = CompanyProfileInput & {
  status?: string;
  plan?: string;
  valid_until?: string | null;
  notes?: string;
  contact_email?: string;
  contact_name?: string;
};

export type TenantAdmin = {
  id: number;
  username: string;
  display_name: string;
  email: string;
  role: string;
  must_change_password: boolean;
  created_at: string;
};

export type CompanySnapshot = {
  id: number;
  code: string;
  name: string;
  rfc: string;
  razon_social: string;
  nombre_comercial: string;
  regimen_fiscal: string;
  registro_patronal: string;
  clase_riesgo: string;
  domicilio_fiscal: string;
  codigo_postal: string;
  ciudad: string;
  estado: string;
  telefono: string;
  email: string;
  representante_legal: string;
  giro: string;
};

export type TenantDetail = {
  id: number;
  code: string;
  name: string;
  status: string;
  plan: string;
  valid_until: string | null;
  notes: string;
  contact_email: string;
  contact_name: string;
  access_sent_at: string | null;
  created_at: string;
  company: CompanySnapshot | null;
  admins: TenantAdmin[];
};

const STATUSES = ["activo", "suspendido", "cancelado"] as const;
const PLANS = ["trial", "basic", "pro"] as const;
const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

/** Usuario admin = el código en minúsculas (corto). */
export function adminUsernameForCode(code: string): string {
  const c = normCompanyCode(code).toLowerCase();
  return c || "emp";
}

/** Prefijo corto (máx. 4) solo desde nombre comercial. */
export function shortCodeFromCommercialName(name: string): string {
  const slug = (name ?? "")
    .toString()
    .normalize("NFD")
    .replace(/\p{M}/gu, "")
    .toUpperCase()
    .replace(/[^A-Z0-9]+/g, "")
    .slice(0, 4);
  return slug.length >= 2 ? slug : (slug || "EMP").padEnd(2, "X").slice(0, 4);
}

/** YYMM de la fecha de alta (refuerzo corto del código). */
export function codeDateStamp(when: Date = new Date()): string {
  const yy = String(when.getFullYear()).slice(-2);
  const mm = String(when.getMonth() + 1).padStart(2, "0");
  return `${yy}${mm}`;
}

function codeExists(platformDb: PlatformDb, appDb: Database, code: string): boolean {
  return !!tenantByCode(platformDb, code) || !!companyByCode(appDb, code);
}

/**
 * Código único: prefijo del nombre comercial + YYMM de creación.
 * Ej. «ARCTEC» en ago-2026 → ARCT2608. Si choca, sufijo numérico.
 */
export function allocateUniqueTenantCode(
  platformDb: PlatformDb,
  appDb: Database,
  nombreComercial: string,
  createdAt: Date = new Date(),
): string {
  const base = shortCodeFromCommercialName(nombreComercial);
  const stamp = codeDateStamp(createdAt);
  const primary = `${base}${stamp}`;
  if (!codeExists(platformDb, appDb, primary)) return primary;
  for (let n = 2; n < 1000; n++) {
    const suffix = String(n);
    const head = base.slice(0, Math.max(2, 4 - suffix.length));
    const candidate = `${head}${stamp}${suffix}`;
    if (candidate.length <= 16 && !codeExists(platformDb, appDb, candidate)) return candidate;
  }
  return `E${stamp}${Date.now().toString(36).toUpperCase().slice(-4)}`;
}

function trim(value: unknown): string {
  return (value ?? "").toString().trim();
}

function isoDateOrNull(value: unknown): string | null {
  const raw = trim(value);
  if (!raw) return null;
  const m = raw.match(/^(\d{4}-\d{2}-\d{2})/);
  return m ? m[1] : null;
}

/** Perfil completo obligatorio en alta/edición SaaS. */
export function requireSaasCompanyFields(
  profile: ReturnType<typeof normalizeCompanyProfile>,
  extra: { contact_name?: string; contact_email?: string } = {},
): string | null {
  const checks: [string, string][] = [
    ["Nombre comercial", profile.nombre_comercial],
    ["Razón social", profile.razon_social],
    ["RFC", profile.rfc],
    ["Régimen fiscal", profile.regimen_fiscal],
    ["Domicilio fiscal", profile.domicilio_fiscal],
    ["Código postal", profile.codigo_postal],
    ["Ciudad", profile.ciudad],
    ["Estado", profile.estado],
    ["Teléfono", profile.telefono],
    ["Email", profile.email],
    ["Representante legal", profile.representante_legal],
  ];
  for (const [label, value] of checks) {
    if (!value) return `${label} obligatorio`;
  }
  if (!EMAIL_RE.test(profile.email)) return "Email inválido";
  if (!/^\d{5}$/.test(profile.codigo_postal)) return "Código postal debe ser 5 dígitos";

  const contactName = trim(extra.contact_name);
  if (!contactName) return "Nombre de contacto obligatorio";
  const contactEmail = profile.email;
  if (!contactEmail || !EMAIL_RE.test(contactEmail)) {
    return "Email obligatorio (ahí se envía el acceso)";
  }
  return null;
}

export function listTenants(platformDb: PlatformDb) {
  return listTenantsRaw(platformDb);
}

export function getTenantDetail(
  platformDb: PlatformDb,
  appDb: Database,
  tenantId: number,
): TenantDetail | null {
  const t = platformDb.prepare(
    `SELECT id, code, name, status, created_at,
      COALESCE(plan, 'trial') AS plan, valid_until, COALESCE(notes, '') AS notes,
      COALESCE(contact_email, '') AS contact_email,
      COALESCE(contact_name, '') AS contact_name,
      access_sent_at
     FROM tenants WHERE id = ?`,
  ).get(tenantId) as
    | {
      id: number;
      code: string;
      name: string;
      status: string;
      created_at: string;
      plan: string;
      valid_until: string | null;
      notes: string;
      contact_email: string;
      contact_name: string;
      access_sent_at: string | null;
    }
    | undefined;
  if (!t) return null;

  const company = appDb.prepare(
    `SELECT id, code, name,
      COALESCE(rfc, '') AS rfc,
      COALESCE(razon_social, '') AS razon_social,
      COALESCE(nombre_comercial, '') AS nombre_comercial,
      COALESCE(regimen_fiscal, '') AS regimen_fiscal,
      COALESCE(registro_patronal, '') AS registro_patronal,
      COALESCE(clase_riesgo, '') AS clase_riesgo,
      COALESCE(domicilio_fiscal, '') AS domicilio_fiscal,
      COALESCE(codigo_postal, '') AS codigo_postal,
      COALESCE(ciudad, '') AS ciudad,
      COALESCE(estado, '') AS estado,
      COALESCE(telefono, '') AS telefono,
      COALESCE(email, '') AS email,
      COALESCE(representante_legal, '') AS representante_legal,
      COALESCE(giro, '') AS giro
     FROM companies WHERE tenant_id = ? AND kind = 'principal' ORDER BY id LIMIT 1`,
  ).get(tenantId) as CompanySnapshot | undefined;

  const admins = (appDb.prepare(
    `SELECT id, username, display_name, COALESCE(email, '') AS email, role,
      COALESCE(must_change_password, 0) AS must_change_password, created_at
     FROM users WHERE tenant_id = ? AND role = 'tenant_admin'
     ORDER BY id`,
  ).all(tenantId) as Array<Record<string, unknown>>).map((a) => ({
    id: Number(a.id),
    username: String(a.username),
    display_name: String(a.display_name),
    email: String(a.email || ""),
    role: String(a.role),
    must_change_password: Boolean(a.must_change_password),
    created_at: String(a.created_at),
  }));

  return {
    ...t,
    company: company ?? null,
    admins,
  };
}

export async function createTenant(
  platformDb: PlatformDb,
  appDb: Database,
  input: CreateTenantInput,
): Promise<{
  tenant?: { id: number; code: string; name: string; status: string };
  admin?: { username: string; temporary_password: string; email: string };
  email?: { sent: boolean; error?: string };
  error?: string;
}> {
  const profileErr = validateCompanyProfile(input, { requireLegal: true });
  if (profileErr) return { error: profileErr };

  const profile = normalizeCompanyProfile(input);
  const completeErr = requireSaasCompanyFields(profile, {
    contact_name: input.contact_name,
  });
  if (completeErr) return { error: completeErr };

  const code = allocateUniqueTenantCode(platformDb, appDb, profile.nombre_comercial);

  const displayName = profile.nombre_comercial;
  const adminUser = adminUsernameForCode(code);
  const contactName = trim(input.contact_name);
  const contactEmail = profile.email;
  const adminName = trim(input.admin_display_name) || contactName;

  const userClash = appDb.prepare("SELECT id FROM users WHERE username = ?").get(adminUser);
  if (userClash) return { error: `Ya existe el usuario ${adminUser}` };

  const plan = trim(input.plan) || "trial";
  if (!(PLANS as readonly string[]).includes(plan)) return { error: "Plan inválido" };
  const validUntil = isoDateOrNull(input.valid_until);
  const notes = trim(input.notes);
  const temporaryPassword = generateSecurePassword();

  platformDb.prepare(
    `INSERT INTO tenants (code, name, status, plan, valid_until, notes, contact_email, contact_name)
     VALUES (?, ?, 'activo', ?, ?, ?, ?, ?)`,
  ).run(code, displayName, plan, validUntil, notes, contactEmail, contactName);
  const tenantId = platformLastId(platformDb);

  try {
    appDb.prepare(
      `INSERT INTO companies (
        code, name, parent_id, kind, status, tenant_id,
        razon_social, nombre_comercial, rfc, regimen_fiscal, registro_patronal, clase_riesgo,
        domicilio_fiscal, codigo_postal, ciudad, estado, telefono, email, representante_legal, giro
      ) VALUES (?, ?, NULL, 'principal', 'activo', ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
    ).run(
      code,
      displayName,
      tenantId,
      profile.razon_social,
      profile.nombre_comercial,
      profile.rfc,
      profile.regimen_fiscal,
      profile.registro_patronal,
      profile.clase_riesgo,
      profile.domicilio_fiscal,
      profile.codigo_postal,
      profile.ciudad,
      profile.estado,
      profile.telefono,
      contactEmail,
      profile.representante_legal,
      profile.giro,
    );
    const companyId = appLastId(appDb);

    const hash = await hashPassword(temporaryPassword);
    appDb.prepare(
      `INSERT INTO users (
        username, password_hash, display_name, company_id, tenant_id, role,
        must_change_password, email
      ) VALUES (?, ?, ?, ?, ?, 'tenant_admin', 1, ?)`,
    ).run(adminUser, hash, adminName, companyId, tenantId, contactEmail);
  } catch (e) {
    platformDb.prepare("DELETE FROM tenants WHERE id = ?").run(tenantId);
    return { error: e instanceof Error ? e.message : "Error al crear empresa" };
  }

  const tenant = platformDb.prepare(
    "SELECT id, code, name, status FROM tenants WHERE id = ?",
  ).get(tenantId) as { id: number; code: string; name: string; status: string };

  let emailResult: { sent: boolean; error?: string } = { sent: false };
  if (input.send_email && contactEmail) {
    emailResult = await sendAccessEmail(platformDb, {
      tenantId,
      companyName: displayName,
      username: adminUser,
      password: temporaryPassword,
      contactEmail,
      contactName,
    });
  } else if (input.send_email && !contactEmail) {
    emailResult = { sent: false, error: "Indique correo de contacto para enviar el acceso" };
  }

  return {
    tenant,
    admin: { username: adminUser, temporary_password: temporaryPassword, email: contactEmail },
    email: emailResult,
  };
}

export function updateTenant(
  platformDb: PlatformDb,
  appDb: Database,
  tenantId: number,
  input: UpdateTenantInput,
): { error?: string } {
  const current = tenantById(platformDb, tenantId);
  if (!current) return { error: "Empresa no encontrada" };

  const company = appDb.prepare(
    `SELECT * FROM companies WHERE tenant_id = ? AND kind = 'principal' ORDER BY id LIMIT 1`,
  ).get(tenantId) as Record<string, unknown> | undefined;

  const profileErr = validateCompanyProfile({
    ...company,
    ...input,
    name: input.nombre_comercial ?? input.name ?? (company?.name as string),
  }, { requireLegal: true });
  if (profileErr) return { error: profileErr };

  const merged: CompanyProfileInput = {
    name: input.name ?? input.nombre_comercial ?? (company?.name as string) ?? current.name,
    nombre_comercial: input.nombre_comercial ?? (company?.nombre_comercial as string) ?? "",
    razon_social: input.razon_social ?? (company?.razon_social as string) ?? "",
    rfc: input.rfc ?? (company?.rfc as string) ?? "",
    regimen_fiscal: input.regimen_fiscal ?? (company?.regimen_fiscal as string) ?? "",
    registro_patronal: input.registro_patronal ?? (company?.registro_patronal as string) ?? "",
    clase_riesgo: input.clase_riesgo ?? (company?.clase_riesgo as string) ?? "",
    domicilio_fiscal: input.domicilio_fiscal ?? (company?.domicilio_fiscal as string) ?? "",
    codigo_postal: input.codigo_postal ?? (company?.codigo_postal as string) ?? "",
    ciudad: input.ciudad ?? (company?.ciudad as string) ?? "",
    estado: input.estado ?? (company?.estado as string) ?? "",
    telefono: input.telefono ?? (company?.telefono as string) ?? "",
    email: input.email ?? (company?.email as string) ?? "",
    representante_legal: input.representante_legal ?? (company?.representante_legal as string) ?? "",
    giro: input.giro ?? (company?.giro as string) ?? "",
  };
  const profile = normalizeCompanyProfile(merged, current.name);

  const row = platformDb.prepare(
    `SELECT COALESCE(plan, 'trial') AS plan, valid_until, COALESCE(notes, '') AS notes,
      COALESCE(contact_email, '') AS contact_email, COALESCE(contact_name, '') AS contact_name
     FROM tenants WHERE id = ?`,
  ).get(tenantId) as {
    plan: string;
    valid_until: string | null;
    notes: string;
    contact_email: string;
    contact_name: string;
  };

  const contactName = input.contact_name !== undefined ? trim(input.contact_name) : row.contact_name;
  const contactEmail = profile.email;

  const completeErr = requireSaasCompanyFields(profile, {
    contact_name: contactName,
  });
  if (completeErr) return { error: completeErr };

  let status = current.status;
  if (input.status !== undefined) {
    if (!(STATUSES as readonly string[]).includes(input.status)) {
      return { error: "Estatus inválido (activo, suspendido, cancelado)" };
    }
    status = input.status;
  }
  if (!status) return { error: "Estatus obligatorio" };

  let plan = row.plan;
  if (input.plan !== undefined) {
    const p = trim(input.plan);
    if (!(PLANS as readonly string[]).includes(p)) return { error: "Plan inválido" };
    plan = p;
  }
  if (!plan) return { error: "Plan obligatorio" };

  let validUntil = row.valid_until;
  if (input.valid_until !== undefined) validUntil = isoDateOrNull(input.valid_until);
  if (!validUntil) return { error: "Vigencia obligatoria" };

  let notes = row.notes;
  if (input.notes !== undefined) notes = trim(input.notes);
  if (!notes) return { error: "Notas internas obligatorias" };

  if (!contactEmail || !EMAIL_RE.test(contactEmail)) {
    return { error: "Email inválido" };
  }
  if (!contactName) return { error: "Nombre de contacto obligatorio" };

  const displayName = profile.nombre_comercial || profile.razon_social || current.name;

  platformDb.prepare(
    `UPDATE tenants SET name = ?, status = ?, plan = ?, valid_until = ?, notes = ?,
      contact_email = ?, contact_name = ? WHERE id = ?`,
  ).run(displayName, status, plan, validUntil, notes, contactEmail, contactName, tenantId);

  if (company?.id) {
    appDb.prepare(
      `UPDATE companies SET
        name = ?, razon_social = ?, nombre_comercial = ?, rfc = ?, regimen_fiscal = ?,
        registro_patronal = ?, clase_riesgo = ?, domicilio_fiscal = ?, codigo_postal = ?,
        ciudad = ?, estado = ?, telefono = ?, email = ?, representante_legal = ?, giro = ?
       WHERE id = ?`,
    ).run(
      displayName,
      profile.razon_social,
      profile.nombre_comercial,
      profile.rfc,
      profile.regimen_fiscal,
      profile.registro_patronal,
      profile.clase_riesgo,
      profile.domicilio_fiscal,
      profile.codigo_postal,
      profile.ciudad,
      profile.estado,
      profile.telefono,
      profile.email || contactEmail,
      profile.representante_legal,
      profile.giro,
      company.id,
    );
  }

  return {};
}

/** Regenera contraseña del admin, marca must_change_password y opcionalmente envía correo. */
export async function issueTenantAdminAccess(
  platformDb: PlatformDb,
  appDb: Database,
  tenantId: number,
  opts: { userId?: number; send_email?: boolean } = {},
): Promise<{
  admin?: { username: string; temporary_password: string; email: string };
  email?: { sent: boolean; error?: string };
  error?: string;
}> {
  const detail = getTenantDetail(platformDb, appDb, tenantId);
  if (!detail) return { error: "Empresa no encontrada" };
  const admin = opts.userId
    ? detail.admins.find((a) => a.id === opts.userId)
    : detail.admins[0];
  if (!admin) return { error: "No hay usuario administrador" };

  const temporaryPassword = generateSecurePassword();
  const hash = await hashPassword(temporaryPassword);
  appDb.prepare(
    `UPDATE users SET password_hash = ?, must_change_password = 1 WHERE id = ? AND tenant_id = ?`,
  ).run(hash, admin.id, tenantId);

  const contactEmail = detail.contact_email || admin.email;
  let emailResult: { sent: boolean; error?: string } = { sent: false };
  if (opts.send_email) {
    if (!contactEmail) {
      emailResult = { sent: false, error: "Falta correo de contacto en la empresa" };
    } else {
      emailResult = await sendAccessEmail(platformDb, {
        tenantId,
        companyName: detail.name,
        username: admin.username,
        password: temporaryPassword,
        contactEmail,
        contactName: detail.contact_name || admin.display_name,
      });
    }
  }

  return {
    admin: {
      username: admin.username,
      temporary_password: temporaryPassword,
      email: contactEmail,
    },
    email: emailResult,
  };
}

async function sendAccessEmail(
  platformDb: PlatformDb,
  opts: {
    tenantId: number;
    companyName: string;
    username: string;
    password: string;
    contactEmail: string;
    contactName: string;
  },
): Promise<{ sent: boolean; error?: string }> {
  const result = await sendMail(platformDb, {
    to: opts.contactEmail,
    subject: `Acceso a PANELS — ${opts.companyName}`,
    text: accessEmailBody({
      companyName: opts.companyName,
      username: opts.username,
      password: opts.password,
      contactName: opts.contactName,
    }),
  });
  if (result.sent) {
    platformDb.prepare(
      `UPDATE tenants SET access_sent_at = datetime('now') WHERE id = ?`,
    ).run(opts.tenantId);
  }
  return result;
}

export function tenantAccessBlocked(platformDb: PlatformDb, tenantId: number | null): string | null {
  if (tenantId == null) return "Cuenta sin empresa asignada";
  const t = platformDb.prepare(
    `SELECT status, valid_until FROM tenants WHERE id = ?`,
  ).get(tenantId) as { status: string; valid_until: string | null } | undefined;
  if (!t) return "Empresa no encontrada";
  if (t.status === "suspendido") return "La suscripción de esta empresa está suspendida";
  if (t.status === "cancelado") return "La cuenta de esta empresa fue cancelada";
  if (t.status !== "activo") return "La empresa no está activa";
  if (t.valid_until) {
    const today = new Date().toISOString().slice(0, 10);
    if (t.valid_until < today) return "La licencia de esta empresa ha vencido";
  }
  return null;
}

export { config };