/**
 * Turn Engine V3 - Dispatcher basado en estados
 * 
 * Flujo: IDLE → CART → SHIPPING → PAYMENT → WAITING_WEBHOOKS
 * Regla universal: add_to_cart SIEMPRE vuelve a CART desde cualquier estado.
 * 
 * Feature flag USE_MODULAR_NLU=true para usar el nuevo sistema NLU modular.
 */

import { llmNluV3 } from "./openai.js";
import { llmNluModular } from "./nlu/index.js";
import { ConversationState, shouldReturnToCart, safeNextState } from "./fsm.js";
import { migrateOldContext, createEmptyOrder } from "./orderModel.js";
import {
  handleIdleState,
  handleCartState,
  handleShippingState,
  handlePaymentState,
  handleWaitingState,
} from "./stateHandlers.js";
import { getStoreConfig } from "../0-ui/db/settingsRepo.js";
import { pushRecent } from "./replyTemplates.js";

// Feature flag para NLU modular
const USE_MODULAR_NLU = process.env.USE_MODULAR_NLU === "true";

/**
 * Genera un resumen corto del historial para el NLU
 */
function shortSummary(history) {
  if (!Array.isArray(history) || history.length === 0) return null;
  const last = history.slice(-6);
  return last
    .map((m) => {
      const role = m.role === "user" ? "U" : "A";
      const txt = String(m.content || "").slice(0, 80);
      return `${role}: ${txt}`;
    })
    .join("\n");
}

/**
 * Punto de entrada principal del turn engine.
 */
export async function runTurnV3({
  tenantId,
  chat_id,
  text,
  prev_state,
  prev_context,
  conversation_history,
}) {
  const audit = {
    trace: {
      tenantId,
      chat_id,
      text_preview: String(text || "").slice(0, 50),
      prev_state,
    },
  };

  // Migrar contexto viejo a nuevo formato de orden
  const order = migrateOldContext(prev_context);

  // Mapear estados viejos a nuevos
  const normalizedState = normalizeState(prev_state);

  // Recent replies para dedup de templates (FIFO cap 8)
  const recentReplies = Array.isArray(prev_context?.recent_replies)
    ? prev_context.recent_replies
    : [];

  // Counter de búsquedas fallidas consecutivas para escalación
  const failedSearches = (prev_context?.failed_searches && typeof prev_context.failed_searches === "object")
    ? prev_context.failed_searches
    : { count: 0, last_query: null, last_at: null };

  // ─────────────────────────────────────────────────────────────
  // NLU (con feature flag para sistema modular)
  // ─────────────────────────────────────────────────────────────
  
  const nluInput = {
    last_user_message: text,
    conversation_state: normalizedState,
    memory_summary: shortSummary(conversation_history),
    pending_context: {
      has_cart_items: (order?.cart?.length || 0) > 0,
      has_pending_items: (order?.pending?.length || 0) > 0,
    },
    last_shown_options: [], // Ya no usamos este campo
    locale: "es-AR",
  };

  // Cargar configuración del tenant (se usa en NLU y handlers)
  const storeConfig = await getStoreConfig({ tenantId });

  let nluResult;
  
  if (USE_MODULAR_NLU) {
    // Nuevo sistema NLU modular con prompts editables
    nluResult = await llmNluModular({ input: nluInput, tenantId, storeConfig });
    audit.nlu = { 
      raw_text: nluResult.raw_text, 
      model: nluResult.model, 
      usage: nluResult.usage, 
      validation: nluResult.validation, 
      parsed: nluResult.nlu,
      routing: nluResult.routing,
      schema: "modular_v1",
    };
  } else {
    // Sistema NLU clásico
    nluResult = await llmNluV3({ input: nluInput });
    audit.nlu = { 
      raw_text: nluResult.raw_text, 
      model: nluResult.model, 
      usage: nluResult.usage, 
      validation: nluResult.validation, 
      parsed: nluResult.nlu,
      schema: "v3",
    };
  }
  
  const nlu = nluResult.nlu;

  // ─────────────────────────────────────────────────────────────
  // Dispatcher por estado
  // ─────────────────────────────────────────────────────────────

  const handlerParams = {
    tenantId,
    chat_id,
    text,
    nlu,
    order,
    audit,
    storeConfig,
    recentReplies,
    conversation_history: conversation_history || [],
    failedSearches,
  };

  // Regla universal: si quiere agregar productos, volver a CART
  const returnToCart = shouldReturnToCart(normalizedState, nlu, text);
  if (returnToCart) {
    const result = await handleCartState({ ...handlerParams, fromIdle: false });
    return formatResult(result, prev_context, recentReplies, failedSearches);
  }

  // Dispatch por estado actual
  let result;
  
  switch (normalizedState) {
    case ConversationState.IDLE:
      result = await handleIdleState(handlerParams);
      break;
      
    case ConversationState.CART:
      result = await handleCartState(handlerParams);
      break;
      
    case ConversationState.SHIPPING:
      result = await handleShippingState(handlerParams);
      break;
      
    case ConversationState.PAYMENT:
      result = await handlePaymentState(handlerParams);
      break;
      
    case ConversationState.WAITING_WEBHOOKS:
      result = await handleWaitingState(handlerParams);
      break;
      
    default:
      // Estado desconocido, tratar como IDLE
      result = await handleIdleState(handlerParams);
  }

  return formatResult(result, prev_context, recentReplies, failedSearches);
}

/**
 * Normaliza estados viejos al nuevo modelo
 */
function normalizeState(state) {
  if (!state) return ConversationState.IDLE;
  
  const s = String(state).toUpperCase();
  
  // Mapeo directo
  if (s === "IDLE") return ConversationState.IDLE;
  if (s === "CART") return ConversationState.CART;
  if (s === "SHIPPING") return ConversationState.SHIPPING;
  if (s === "PAYMENT") return ConversationState.PAYMENT;
  if (s === "WAITING_WEBHOOKS") return ConversationState.WAITING_WEBHOOKS;
  
  // Estados viejos → CART
  if (["CART_ACTIVE", "BROWSING", "CLARIFYING_ITEMS", "AWAITING_QUANTITY"].includes(s)) {
    return ConversationState.CART;
  }
  
  // Estados de checkout viejos
  if (s === "CLARIFYING_PAYMENT") return ConversationState.PAYMENT;
  if (s === "CLARIFYING_SHIPPING") return ConversationState.SHIPPING;
  if (s === "AWAITING_ADDRESS") return ConversationState.SHIPPING;
  if (s === "AWAITING_PAYMENT") return ConversationState.WAITING_WEBHOOKS;
  if (s === "COMPLETED") return ConversationState.IDLE; // Nuevo ciclo
  
  return ConversationState.IDLE;
}

/**
 * Formatea el resultado para compatibilidad con el sistema existente
 */
function formatResult(result, prevContext, recentReplies = [], failedSearches = { count: 0 }) {
  const { plan, decision } = result;
  const order = decision?.order || createEmptyOrder();

  // Mergear template_ids usados por los handlers en recent_replies
  const idsUsed = Array.isArray(decision?.template_ids_used)
    ? decision.template_ids_used.filter(Boolean)
    : [];
  let nextRecent = recentReplies;
  for (const id of idsUsed) {
    nextRecent = pushRecent(nextRecent, id);
  }

  // failed_searches: handlers pueden devolver decision.failed_searches_next.
  // Si no, mantener el previo.
  const nextFailedSearches = decision?.failed_searches_next || failedSearches;
  
  // Construir context_patch para compatibilidad con pipeline
  const context_patch = {
    // Nueva estructura
    order,
    
    // Compatibilidad: también guardar en formato viejo para UI/pipeline existente
    order_basket: {
      items: (order.cart || []).map(item => ({
        product_id: item.woo_id,
        woo_product_id: item.woo_id,
        quantity: item.qty,
        unit: item.unit,
        label: item.name,
        name: item.name,
        price: item.price,
      })),
    },
    pending_items: (order.pending || []).map(p => ({
      id: p.id,
      query: p.query,
      candidates: p.candidates,
      resolved_product: p.selected_woo_id ? {
        woo_product_id: p.selected_woo_id,
        name: p.selected_name,
        price: p.selected_price,
        display_unit: p.selected_unit,
      } : null,
      quantity: p.qty,
      unit: p.unit,
      status: p.status?.toLowerCase() || "needs_type",
    })),
    payment_method: order.payment_type,
    shipping_method: order.is_delivery === true ? "delivery" : 
                     order.is_delivery === false ? "pickup" : null,
    delivery_address: order.shipping_address ? { text: order.shipping_address } : null,
    woo_order_id: order.woo_order_id,

    // Dedup de respuestas: ids de templates usados, FIFO cap 8
    recent_replies: nextRecent,
    // Counter de búsquedas fallidas para escalación
    failed_searches: nextFailedSearches,
  };
  
  // Construir basket_resolved para UI
  const basket_resolved = {
    items: (order.cart || []).map(item => ({
      product_id: item.woo_id,
      woo_product_id: item.woo_id,
      quantity: item.qty,
      unit: item.unit,
      label: item.name,
      name: item.name,
      price: item.price,
    })),
  };
  
  return {
    plan: {
      ...plan,
      basket_resolved,
    },
    decision: {
      actions: decision?.actions || [],
      context_patch,
      audit: decision?.audit || {},
    },
  };
}

// Re-exportar safeNextState para compatibilidad
export { safeNextState } from "./fsm.js";