package com.superbiz.agent.service;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.superbiz.agent.dto.ComparableRetrievalResult;
import org.springframework.ai.document.Document;
import org.springframework.stereotype.Component;

import java.util.LinkedHashMap;
import java.util.Map;

@Component
public class RetrievalResultNormalizer {

    private final ObjectMapper objectMapper;

    public RetrievalResultNormalizer(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }

    public ComparableRetrievalResult fromCurrent(VectorSearchService.SearchResult result, int rank, int previewLimit) {
        Map<String, String> metadata = parseMetadata(result.getMetadata());
        String source = firstNonBlank(metadata.get("_source"), metadata.get("source"), result.getMetadata(), result.getId());
        return ComparableRetrievalResult.builder()
                .path("current")
                .rank(rank)
                .id(result.getId())
                .source(source)
                .docId(metadata.get("docId"))
                .title(metadata.get("title"))
                .breadcrumb(metadata.get("breadcrumb"))
                .category(metadata.get("category"))
                .contentPreview(truncate(result.getContent(), previewLimit))
                .scoreLabel("l2_distance")
                .scoreValue((double) result.getScore())
                .build();
    }

    public ComparableRetrievalResult fromSidecar(Document document, int rank, int previewLimit) {
        Map<String, String> metadata = stringifyMetadata(document.getMetadata());
        String source = firstNonBlank(metadata.get("_source"), metadata.get("source"), metadata.get("docId"), document.getId());
        return ComparableRetrievalResult.builder()
                .path("sidecar")
                .rank(rank)
                .id(document.getId())
                .source(source)
                .docId(metadata.get("docId"))
                .title(metadata.get("title"))
                .breadcrumb(metadata.get("breadcrumb"))
                .category(metadata.get("category"))
                .contentPreview(truncate(document.getText(), previewLimit))
                .scoreLabel("similarity")
                .scoreValue(document.getScore())
                .build();
    }

    private Map<String, String> parseMetadata(String metadata) {
        if (metadata == null || metadata.isBlank()) {
            return Map.of();
        }
        try {
            Map<?, ?> raw = objectMapper.readValue(metadata, Map.class);
            return stringifyMetadata(raw);
        } catch (Exception e) {
            return Map.of();
        }
    }

    private Map<String, String> stringifyMetadata(Map<?, ?> raw) {
        if (raw == null || raw.isEmpty()) {
            return Map.of();
        }
        Map<String, String> result = new LinkedHashMap<>();
        for (Map.Entry<?, ?> entry : raw.entrySet()) {
            if (entry.getKey() != null && entry.getValue() != null) {
                result.put(String.valueOf(entry.getKey()), String.valueOf(entry.getValue()));
            }
        }
        return result;
    }

    private String firstNonBlank(String... values) {
        for (String value : values) {
            if (value != null && !value.isBlank()) {
                return value;
            }
        }
        return null;
    }

    private String truncate(String text, int maxLength) {
        if (text == null || text.length() <= maxLength) {
            return text;
        }
        return text.substring(0, maxLength) + "...";
    }
}