import { IModuleServer, ModuleParams } from "@erp/core/api";
import { logger } from "../logger";
import { initModels, registerModels } from "./model-loader";
import { registerService } from "./service-registry";

const registeredModules: Map<string, IModuleServer> = new Map();
const initializedModules = new Set<string>();
const visiting = new Set<string>(); // para detección de ciclos

/**
  Registra un módulo del servidor en el registry.
  Lanza error si el nombre ya existe.
*/
export function registerModule(pkg: IModuleServer) {
  if (!pkg?.name) {
    throw new Error('❌ Invalid module: missing "name" property');
  }
  if (registeredModules.has(pkg.name)) {
    throw new Error(`❌ Module "${pkg.name}" already registered`);
  }
  registeredModules.set(pkg.name, pkg);
  logger.info(`📦 Module enqueued: "${pkg.name}"`, { label: "moduleRegistry" });
}

/**
  Inicializa todos los módulos registrados (resolviendo dependencias),
  y al final inicializa los modelos (Sequelize) en bloque.
*/
export async function initModules(params: ModuleParams) {
  for (const name of registeredModules.keys()) {
    await loadModule(name, params, []); // secuencial para logs deterministas
  }
  await withPhase("global", "initModels", async () => {
    await initModels(params);
  });
}

/**
  Carga recursivamente un módulo y sus dependencias con detección de ciclos.
*/
async function loadModule(name: string, params: ModuleParams, stack: string[]) {
  if (initializedModules.has(name)) return;

  if (visiting.has(name)) {
    // Ciclo detectado: construir traza legible
    const cyclePath = [...stack, name].join(" -> ");
    throw new Error(`❌ Cyclic dependency detected: ${cyclePath}`);
  }

  const pkg = registeredModules.get(name);
  if (!pkg) {
    throw new Error(
      `❌ Module "${name}" not found (required by: ${stack[stack.length - 1] ?? "root"})`
    );
  }

  visiting.add(name);
  stack.push(name);

  // 1) Resolver dependencias primero (en orden)
  const deps = pkg.dependencies || [];
  for (const dep of deps) {
    await loadModule(dep, params, stack.slice());
  }

  // 2) Inicializar el módulo (permite async)
  await withPhase(name, "init", async () => {
    await Promise.resolve(pkg.init(params));
  });

  // 3) Registrar dependencias que expone (permite async)
  const pkgApi = await withPhase(name, "registerDependencies", async () => {
    return await Promise.resolve(pkg.registerDependencies?.(params));
  });

  // 4) Registrar modelos de Sequelize, si existen
  if (pkgApi?.models) {
    await withPhase(name, "registerModels", async () => {
      await Promise.resolve(registerModels(pkgApi.models, params, { moduleName: pkg.name }));
    });
  }

  // 5) Registrar servicios, si existen
  if (pkgApi?.services && typeof pkgApi.services === "object") {
    await withPhase(name, "registerServices", async () => {
      await Promise.resolve(registerService(pkg.name, pkgApi.services));
    });
  }

  initializedModules.add(name);
  visiting.delete(name);
  stack.pop();

  logger.info(`✅ Module "${name}" registered`, { label: "moduleRegistry" });
}

/** 
  Helper para anotar fase y módulo en errores y logs.
*/
async function withPhase<T>(
  moduleName: string,
  phase: "init" | "registerDependencies" | "registerModels" | "registerServices" | "initModels",
  fn: () => Promise<T> | T
): Promise<T> {
  try {
    return await fn();
  } catch (error: any) {
    // Log enriquecido con contexto
    logger.error(
      `⛔️ Module "${moduleName}" failed at phase="${phase}": ${error?.message ?? error}`,
      {
        label: "moduleRegistry",
        module: moduleName,
        phase,
        stack: error?.stack,
      }
    );
    // Re-lanzamos con contexto preservado
    const err = new Error(
      `[module=${moduleName}] phase=${phase} failed: ${error?.message ?? "Unknown error"}`
    );
    (err as any).cause = error;
    throw err;
  }
}