import org.jetbrains.annotations.Nullable;
import org.jetbrains.annotations.PropertyKey;
import org.mvnsearch.model.ProblemDetailException;
import org.slf4j.helpers.FormattingTuple;
import org.slf4j.helpers.MessageFormatter;
import org.springframework.http.ProblemDetail;
import org.springframework.web.reactive.result.method.annotation.ResponseEntityExceptionHandler;

import java.net.URI;
import java.util.Locale;
import java.util.ResourceBundle;

public class ProblemDetailExceptionHandler extends ResponseEntityExceptionHandler {
    private static final String BUNDLE_FQN = "app.ErrorMessages";
    //please use your own error message properties file
    private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle.getBundle(BUNDLE_FQN, new Locale("en", "US"));
    private static final String[] URL_PREFIXES = new String[]{"https://", "http://"};

    public static ProblemDetail fromProblemDetailException(ProblemDetailException e, Object... params) {
        return fromErrorCode(e, e.getHttpStatusCode(), e.getErrorCode(), params);
    }

    public static ProblemDetail fromErrorCode(Exception e, int httpStatusCode,
                                              @PropertyKey(resourceBundle = BUNDLE_FQN) String errorCode, Object... params) {
        String message = errorMessage(errorCode, params);
        ProblemDetail problemDetail = ProblemDetail.forStatus(httpStatusCode);
        problemDetail.setTitle(e.getClass().getCanonicalName());
        problemDetail.setDetail(message);
        final URI type = extractUri(message);
        if (type != null) {
            problemDetail.setType(type);
        }
        problemDetail.setProperty("errorCode", errorCode);
        if (params != null && params.length > 0) {
            problemDetail.setProperty("params", params);
        }
        return problemDetail;
    }

    @Nullable
    private static URI extractUri(String message) {
        for (String urlPrefix : URL_PREFIXES) {
            if (message.contains(urlPrefix)) {
                int offset = message.indexOf(urlPrefix);
                int endOffset = message.indexOf(" ", offset);
                if (endOffset == -1) {
                    endOffset = message.length();
                }
                return URI.create(message.substring(offset, endOffset));
            }
        }
        return null;
    }

    public static String errorMessage(@PropertyKey(resourceBundle = BUNDLE_FQN) String key, Object... params) {
        if (RESOURCE_BUNDLE.containsKey(key)) {
            String value = RESOURCE_BUNDLE.getString(key);
            final FormattingTuple tuple = MessageFormatter.arrayFormat(value, params);
            return key + " - " + tuple.getMessage();
        } else {
            return MessageFormatter.arrayFormat(key, params).getMessage();
        }
    }
}