package com.wok.supportbot.app;

import com.fasterxml.jackson.annotation.JsonInclude;
import org.springframework.ai.document.Document;

import java.util.List;
import java.util.Map;

/** Public citation metadata from the documents actually used by this answer. */
@JsonInclude(JsonInclude.Include.ALWAYS)
public record SourceReference(String documentId, String title, String sourceName,
                              Integer chunkIndex, Double score, String snippet) {

    public SourceReference {
        if (snippet != null && snippet.length() > 160) {
            int end = Character.isHighSurrogate(snippet.charAt(158)) ? 158 : 159;
            snippet = snippet.substring(0, end) + "…";
        }
    }

    public static List<SourceReference> fromDocuments(List<Document> documents) {
        if (documents == null || documents.isEmpty()) {
            return List.of();
        }
        return documents.stream().map(SourceReference::fromDocument).toList();
    }

    private static SourceReference fromDocument(Document document) {
        Map<String, Object> metadata = document.getMetadata();
        // Preserve the published source endpoint's distance semantics; other retrievers expose score.
        Object score = metadata.get("distance") != null ? metadata.get("distance") : metadata.get("score");
        return new SourceReference(stringValue(metadata.get("documentId")),
                stringValue(metadata.get("title")), stringValue(metadata.get("sourceName")),
                integerValue(metadata.get("chunkIndex")), doubleValue(score), document.getText());
    }

    private static String stringValue(Object value) {
        return value == null ? null : value.toString();
    }

    private static Integer integerValue(Object value) {
        if (value == null) return null;
        try {
            return Integer.valueOf(value.toString());
        } catch (NumberFormatException ignored) {
            return null;
        }
    }

    private static Double doubleValue(Object value) {
        if (value == null) return null;
        try {
            double number = Double.parseDouble(value.toString());
            return Double.isFinite(number) ? number : null;
        } catch (NumberFormatException ignored) {
            return null;
        }
    }
}