/*
 * Copyright 2025 Google. This software is provided as-is, without warranty or representation for any use or purpose.
 * Your use of it is subject to your agreement with Google.
 */

package com.example.mapper.conversation;

import com.example.dto.dialogflow.base.DetectIntentRequestDTO;
import com.example.dto.dialogflow.conversation.ExternalConvRequestDTO;
import com.example.dto.dialogflow.conversation.QueryInputDTO;
import com.example.dto.dialogflow.conversation.QueryParamsDTO;
import com.example.dto.dialogflow.conversation.TextInputDTO;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

/**
 * Spring component responsible for mapping a simplified, external API request
 * into a structured `DetectIntentRequestDTO` for Dialogflow. It processes
 * user messages and relevant context, such as phone numbers and channel information,
 * and populates the `QueryInputDTO` and `QueryParamsDTO` fields required for
 * a Dialogflow API call.
 */
@Component
public class ExternalConvRequestMapper {

    private static final Logger logger = LoggerFactory.getLogger(ExternalConvRequestMapper.class);
    private static final String DEFAULT_LANGUAGE_CODE = "es";

    public DetectIntentRequestDTO mapExternalRequestToDetectIntentRequest(ExternalConvRequestDTO externalRequest) {
        Objects.requireNonNull(externalRequest, "ExternalRequestDTO cannot be null for mapping.");

        if (externalRequest.message() == null || externalRequest.message().isBlank()) {
            throw new IllegalArgumentException("External request 'mensaje' (message) is required.");
        }
        TextInputDTO textInput = new TextInputDTO(externalRequest.message());
        QueryInputDTO queryInputDTO = new QueryInputDTO(textInput,null,DEFAULT_LANGUAGE_CODE);

        // 2. Map ALL relevant external fields into QueryParamsDTO.parameters
        Map<String, Object> parameters = new HashMap<>();

        String primaryPhoneNumber = null;
        if (externalRequest.user() != null && externalRequest.user().telefono() != null
                && !externalRequest.user().telefono().isBlank()) {
            primaryPhoneNumber = externalRequest.user().telefono();
            parameters.put("telefono", primaryPhoneNumber);
        }

        if (primaryPhoneNumber == null || primaryPhoneNumber.isBlank()) {
            throw new IllegalArgumentException(
                    "Phone number is required in the 'usuario' field for conversation management.");
        }

        String resolvedUserId = null;
        // Derive from phone number if not provided by 'userId' parameter
        resolvedUserId = "user_by_phone_" + primaryPhoneNumber.replaceAll("[^0-9]", "");
        parameters.put("usuario_id", resolvedUserId); // Ensure derived ID is also in params
        logger.warn("User ID not provided in external request. Using derived ID from phone number: {}", resolvedUserId);


        if (externalRequest.channel() != null && !externalRequest.channel().isBlank()) {
            parameters.put("canal", externalRequest.channel());
            logger.debug("Mapped 'canal' from external request: {}", externalRequest.channel());
        }

        if (externalRequest.user() != null && externalRequest.user().nickname() != null
                && !externalRequest.user().nickname().isBlank()) {
            parameters.put("nickname", externalRequest.user().nickname());
            logger.debug("Mapped 'nickname' from external request: {}", externalRequest.user().nickname());
        }
        if (externalRequest.tipo() != null) {
            parameters.put("tipo", externalRequest.tipo());
            logger.debug("Mapped 'tipo' from external request: {}", externalRequest.tipo());
        }

        QueryParamsDTO queryParamsDTO = new QueryParamsDTO(parameters);

        // 3. Construct the final DetectIntentRequestDTO
        return new DetectIntentRequestDTO(queryInputDTO, queryParamsDTO);
    }
}