import type { IModuleServer, ModuleParams } from "@erp/core/api";

import { logger } from "../logger";

import { initModels, registerModels } from "./model-loader";
import { getServiceScoped, listServices, registerService } from "./service-registry";

const registeredModules: Map<string, IModuleServer> = new Map();

// Nuevo: control por fases
const setupDone = new Set<string>(); // para detección de ciclos
const visiting = new Set<string>();
const setupOrder: string[] = [];

// Internal store
const internalByModule: Map<string, Record<string, unknown>> = new Map();

// Tracking de dependencias realmente usadas por módulo
const usedDependenciesByModule: Map<string, Set<string>> = new Map();

// Warmup config (valores por defecto seguros)
const WARMUP_TIMEOUT_MS = Number(process.env.WARMUP_TIMEOUT_MS) || 10_000;
const WARMUP_STRICT =
  String(process.env.WARMUP_STRICT ?? "false")
    .toLowerCase()
    .trim() === "true";

/**
  - 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),
  - luego inicializa los modelos (Sequelize) en bloque y, por último, ejecuta warmups opcionales.
*/
export async function initModules(params: ModuleParams) {
  // 1) SETUP
  for (const name of registeredModules.keys()) {
    await setupModule(name, params, []); // secuencial para logs deterministas
  }

  // 2) MODELS global
  await withPhase("global", "initModels", async () => await initModels(params));

  // 3) START por orden de setup
  for (const name of setupOrder) {
    const pkg = registeredModules.get(name);
    if (!pkg?.start) continue;

    // Si aún hay rastros del anterior init/registerDependencies en algún módulo:
    //   - start() ≈ init() en el contrato nuevo
    //   - setup() ≈ registerDependencies() en el contrato nuevo
    await withPhase(name, "start", async () => {
      // Aquí YA se permite getService/getInternal
      await Promise.resolve(
        pkg.start?.({
          ...params,
          getService: makeGetService(name, pkg),
          getInternal: makeGetInternal(name),
          listServices, // opcional: útil en debugging
        } as any)
      );
    });
  }

  // 4) WARMUP opcional
  await warmupModules(params);

  // 5) Validación dependencias usadas vs declaradas
  validateModuleDependencies();
}

/**
 * SETUP recursivo: resuelve deps, ejecuta setup del módulo (antiguo "registerDependencies"),
 * registra modelos/servicios/internal, y guarda orden.
 */
async function setupModule(name: string, params: ModuleParams, stack: string[]) {
  if (setupDone.has(name)) return;

  if (visiting.has(name)) {
    throw new Error(`❌ Cyclic dependency detected: ${[...stack, name].join(" -> ")}`);
  }

  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) deps first
  for (const dep of pkg.dependencies ?? []) {
    await setupModule(dep, params, stack.slice());
  }

  // 2) setup phase (contrato nuevo) = registerDependencies (en tu código actual)
  const pkgApi = await withPhase(name, "setup", async () => {
    return await Promise.resolve(
      pkg.setup?.({
        ...params,
        // En setup se permite getService para wiring.
        getService: makeGetService(name, pkg),
        listServices,
      } as any)
    );
  });

  // 3) internal store
  if (pkgApi?.internal) {
    internalByModule.set(name, pkgApi.internal as Record<string, unknown>);
  } else {
    internalByModule.set(name, {});
  }

  // 4) models
  if (pkgApi?.models) {
    await withPhase(name, "registerModels", async () => {
      await Promise.resolve(registerModels(pkgApi.models, params, { moduleName: name }));
    });
  }

  // 5) services (namespaced)
  if (pkgApi?.services) {
    await withPhase(name, "registerServices", async () => {
      validateModuleServices(name, pkgApi.services);

      for (const [serviceKey, serviceApi] of Object.entries(pkgApi.services!)) {
        const fullName = buildServiceName(name, serviceKey);
        registerService(fullName, serviceApi);
      }
    });
  }

  setupDone.add(name);
  setupOrder.push(name);

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

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

/** getService instrumentado + scoped */
function makeGetService(moduleName: string, pkg: IModuleServer) {
  return <T>(serviceName: string): T => {
    const [serviceModule] = serviceName.split(":");

    // No registrar dependencias para modulos
    // que usan sus propios servicios.
    if (serviceModule !== "self") {
      trackDependencyUse(moduleName, serviceModule);
    }

    // IMPORTANTE: devolver el valor
    return getServiceScoped<T>(moduleName, pkg.dependencies ?? [], serviceName);
  };
}

/** getInternal: por defecto solo permite al propio módulo acceder a su internal */
function makeGetInternal(requesterModule: string) {
  return <T>(moduleName: string, key?: string): T => {
    if (moduleName !== requesterModule) {
      throw new Error(
        `Module "${requesterModule}" attempted to access internal of "${moduleName}". ` +
          "Internal is private to the owning module."
      );
    }

    const internal = internalByModule.get(moduleName) ?? {};
    if (!key) return internal as unknown as T;

    if (!(key in internal)) {
      throw new Error(`Internal key "${key}" not found in module "${moduleName}".`);
    }
    return internal[key] as T;
  };
}

function trackDependencyUse(requester: string, dep: string) {
  let set = usedDependenciesByModule.get(requester);
  if (!set) {
    set = new Set();
    usedDependenciesByModule.set(requester, set);
  }
  set.add(dep);
}

function buildServiceName(moduleName: string, serviceKey: string): string {
  return `${moduleName}:${serviceKey}`;
}

function validateModuleServices(moduleName: string, services: Record<string, unknown>) {
  for (const [serviceKey, serviceApi] of Object.entries(services)) {
    if (!serviceKey || typeof serviceKey !== "string") {
      throw new Error(`Invalid service key from module "${moduleName}"`);
    }

    const fullName = `${moduleName}:${serviceKey}`;

    if (serviceApi === undefined) {
      throw new Error(`Service "${fullName}" is undefined`);
    }
  }
}

function validateModuleDependencies() {
  for (const [moduleName, pkg] of registeredModules.entries()) {
    const declared = new Set(pkg.dependencies ?? []);
    const used = usedDependenciesByModule.get(moduleName) ?? new Set<string>();

    // ❌ usadas pero no declaradas
    const undeclaredUsed = [...used].filter((d) => !declared.has(d));

    if (undeclaredUsed.length > 0) {
      throw new Error(
        `❌ Module "${moduleName}" used undeclared dependencies: ${undeclaredUsed.join(", ")}`
      );
    }

    // ⚠️ declaradas pero no usadas (opcional)
    const unusedDeclared = [...declared].filter((d) => !used.has(d));
    if (unusedDeclared.length > 0) {
      logger.warn(
        `⚠️  Module "${moduleName}" declared unused dependencies: ${unusedDeclared.join(", ")}`,
        { label: "moduleRegistry", module: moduleName }
      );
    }
  }
}

/**
  - Ejecuta warmup() opcional de cada módulo en orden de inicialización.
  - Si WARMUP_STRICT=true, un fallo aborta el arranque; si no, se avisa y continúa.
*/
async function warmupModules(params: ModuleParams) {
  logger.info("🌡️ Warmup: starting...", { label: "moduleRegistry" });

  for (const name of setupOrder) {
    const pkg = registeredModules.get(name);
    if (!pkg?.warmup) continue;

    const maybeWarmup = (pkg as any).warmup as undefined | ((p: any) => Promise<void> | void);
    if (typeof maybeWarmup !== "function") continue;

    try {
      await withPhase(name, "warmup", () =>
        withTimeout(
          Promise.resolve(
            maybeWarmup({
              ...params,
              getService: makeGetService(name, pkg),
              getInternal: makeGetInternal(name),
              listServices,
            })
          ),
          WARMUP_TIMEOUT_MS,
          `${name}.warmup`
        )
      );
    } catch (error) {
      if (WARMUP_STRICT) {
        logger.error("⛔️ Warmup failed (strict=true). Aborting.", {
          label: "moduleRegistry",
          module: name,
          error,
        });
        throw error;
      }

      logger.warn("⚠️ Warmup failed but continuing (strict=false)", {
        label: "moduleRegistry",
        module: name,
        error,
      });
    }
  }

  logger.info("🌡️ Warmup: done.", { label: "moduleRegistry" });
}

/**
  Helper para anotar fase y módulo en logs (inicio/fin/duración) y errores.
*/
async function withPhase<T>(
  moduleName: string,
  phase: "setup" | "start" | "registerModels" | "registerServices" | "initModels" | "warmup",
  fn: () => Promise<T> | T
): Promise<T> {
  const startedAt = Date.now();
  logger.info(`▶️ phase=start module=${moduleName} ${phase}`, {
    label: "moduleRegistry",
    module: moduleName,
    phase,
  });

  try {
    const out = await fn();
    const duration = Date.now() - startedAt;
    logger.info(`✅ phase=done module=${moduleName} ${phase} durationMs=${duration}`, {
      label: "moduleRegistry",
      module: moduleName,
      phase,
      durationMs: duration,
    });
    return out;
  } catch (error: any) {
    const duration = Date.now() - startedAt;
    logger.error(
      `⛔️ Module "${moduleName}" failed at phase="${phase}" after ${duration}ms: ${error?.message ?? error}`,
      {
        label: "moduleRegistry",
        module: moduleName,
        phase,
        durationMs: duration,
        stack: error?.stack,
      }
    );
    // Re-lanzamos con contexto preservado
    const err = new Error(
      `[module=${moduleName}] phase=${phase} failed: ${error?.message ?? "Unknown error"}`
    );
    (err as any).cause = error;
    throw err;
  }
}

/**
Promesa con timeout; rechaza si excede el tiempo dado.
*/
function withTimeout<T>(p: Promise<T>, ms: number, label: string): Promise<T> {
  let timer: NodeJS.Timeout | null = null;
  const timeout = new Promise<T>((_, reject) => {
    timer = setTimeout(() => {
      reject(new Error(`Timeout after ${ms}ms (${label})`));
    }, ms).unref();
  });
  return Promise.race([p, timeout]).finally(() => {
    if (timer) clearTimeout(timer);
  }) as Promise<T>;
}