/*
 * 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.QueryInputDTO;
import com.example.util.ProtobufUtil;
import com.google.cloud.dialogflow.cx.v3.EventInput;
import com.google.cloud.dialogflow.cx.v3.DetectIntentRequest;

import com.google.cloud.dialogflow.cx.v3.QueryInput;
import com.google.cloud.dialogflow.cx.v3.QueryParameters;
import com.google.cloud.dialogflow.cx.v3.TextInput;
import com.google.protobuf.Struct;
import com.google.protobuf.Value;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.util.Map;
import java.util.Objects;

/**
 * Spring component responsible for mapping a custom `DetectIntentRequestDTO`
 * into a Dialogflow CX `DetectIntentRequest.Builder`. It handles the conversion
 * of user text or event inputs and the serialization of custom session parameters,
 * ensuring the data is in the correct Protobuf format for API communication.
 */
@Component
public class DialogflowRequestMapper {

    private static final Logger logger = LoggerFactory.getLogger(DialogflowRequestMapper.class);

    @org.springframework.beans.factory.annotation.Value("${dialogflow.default-language-code:es}")
    String defaultLanguageCode;

    public DetectIntentRequest.Builder mapToDetectIntentRequestBuilder(DetectIntentRequestDTO requestDto) {
        Objects.requireNonNull(requestDto, "DetectIntentRequestDTO cannot be null for mapping.");

        logger.debug(
                "Building partial Dialogflow CX DetectIntentRequest Protobuf Builder from DTO (only QueryInput and QueryParams).");
        QueryInput.Builder queryInputBuilder = QueryInput.newBuilder();
        QueryInputDTO queryInputDTO = requestDto.queryInput();

        String languageCodeToSet = (queryInputDTO.languageCode() != null
                && !queryInputDTO.languageCode().trim().isEmpty())
                        ? queryInputDTO.languageCode()
                        : defaultLanguageCode;
        queryInputBuilder.setLanguageCode(languageCodeToSet);
        logger.debug("Setting languageCode for QueryInput to: {}", languageCodeToSet);

        if (queryInputDTO.text() != null && queryInputDTO.text().text() != null
                && !queryInputDTO.text().text().trim().isEmpty()) {
            queryInputBuilder.setText(TextInput.newBuilder()
                    .setText(queryInputDTO.text().text())
                    .build());
            logger.debug("Mapped text input for QueryInput: '{}'", queryInputDTO.text().text());

        } else if (queryInputDTO.event() != null && queryInputDTO.event().event() != null
                && !queryInputDTO.event().event().trim().isEmpty()) {
            queryInputBuilder.setEvent(EventInput.newBuilder()
                    .setEvent(queryInputDTO.event().event())
                    .build());
            logger.debug("Mapped event input for QueryInput: '{}'", queryInputDTO.event().event());

        } else {
            logger.error("Dialogflow query input (either text or event) is required and must not be empty.");
            throw new IllegalArgumentException("Dialogflow query input (either text or event) is required.");
        }

        QueryParameters.Builder queryParametersBuilder = QueryParameters.newBuilder();
        Struct.Builder paramsStructBuilder = Struct.newBuilder();

        if (requestDto.queryParams() != null && requestDto.queryParams().parameters() != null) {
            for (Map.Entry<String, Object> entry : requestDto.queryParams().parameters().entrySet()) {
                Value protobufValue = ProtobufUtil.convertJavaObjectToProtobufValue(entry.getValue());
                paramsStructBuilder.putFields(entry.getKey(), protobufValue);
                logger.debug("Added session parameter from DTO queryParams: Key='{}', Value='{}'",
                entry.getKey(),entry.getValue());
            }
        }

        if (paramsStructBuilder.getFieldsCount() > 0) {
            queryParametersBuilder.setParameters(paramsStructBuilder.build());
            logger.debug("All custom session parameters added to Protobuf request builder.");
        } else {
            logger.debug("No custom session parameters to add to Protobuf request.");
        }

        DetectIntentRequest.Builder detectIntentRequestBuilder = DetectIntentRequest.newBuilder()
                .setQueryInput(queryInputBuilder.build());

        if (queryParametersBuilder.hasParameters()) {
            detectIntentRequestBuilder.setQueryParams(queryParametersBuilder.build());
        }

        logger.debug("Finished building partial DetectIntentRequest Protobuf Builder.");
        return detectIntentRequestBuilder;
    }
}