/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.common.xcontent;

import org.elasticsearch.common.logging.DeprecationCategory;
import org.elasticsearch.common.logging.DeprecationLogger;
import org.elasticsearch.xcontent.DeprecationHandler;
import org.elasticsearch.xcontent.ParseField;
import org.elasticsearch.xcontent.XContentLocation;
import org.elasticsearch.xcontent.XContentParserConfiguration;

import java.util.function.Supplier;

/**
 * Logs deprecations to the {@link DeprecationLogger}.
 * <p>
 * This is core's primary implementation of {@link DeprecationHandler} and
 * should <strong>absolutely</strong> be used everywhere where it parses
 * requests. It is much less appropriate when parsing responses from external
 * sources because it will report deprecated fields back to the user as
 * though the user sent them.
 */
public class LoggingDeprecationHandler implements DeprecationHandler {
    /**
     * The logger to which to send deprecation messages.
     * <p>
     * This uses ParseField's logger because that is the logger that
     * we have been using for many releases for deprecated fields.
     * Changing that will require some research to make super duper
     * sure it is safe.
     */
    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(ParseField.class);

    public static final LoggingDeprecationHandler INSTANCE = new LoggingDeprecationHandler();
    public static final XContentParserConfiguration XCONTENT_PARSER_CONFIG = XContentParserConfiguration.EMPTY.withDeprecationHandler(
        INSTANCE
    );

    private LoggingDeprecationHandler() {
        // one instance only
    }

    @Override
    public void logRenamedField(String parserName, Supplier<XContentLocation> location, String oldName, String currentName) {
        logRenamedField(parserName, location, oldName, currentName, false);
    }

    @Override
    public void logReplacedField(String parserName, Supplier<XContentLocation> location, String oldName, String replacedName) {
        logReplacedField(parserName, location, oldName, replacedName, false);
    }

    @Override
    public void logRemovedField(String parserName, Supplier<XContentLocation> location, String removedName) {
        logRemovedField(parserName, location, removedName, false);
    }

    @Override
    public void logRenamedField(
        String parserName,
        Supplier<XContentLocation> location,
        String oldName,
        String currentName,
        boolean isCompatibleDeprecation
    ) {
        String prefix = parserLocation(parserName, location);
        log(
            isCompatibleDeprecation,
            "{}Deprecated field [{}] used, expected [{}] instead",
            new Object[] { prefix, oldName, currentName },
            oldName
        );
    }

    @Override
    public void logReplacedField(
        String parserName,
        Supplier<XContentLocation> location,
        String oldName,
        String replacedName,
        boolean isCompatibleDeprecation
    ) {
        String prefix = parserLocation(parserName, location);
        log(
            isCompatibleDeprecation,
            "{}Deprecated field [{}] used, replaced by [{}]",
            new Object[] { prefix, oldName, replacedName },
            oldName
        );
    }

    @Override
    public void logRemovedField(
        String parserName,
        Supplier<XContentLocation> location,
        String removedName,
        boolean isCompatibleDeprecation
    ) {
        String prefix = parserLocation(parserName, location);
        log(
            isCompatibleDeprecation,
            "{}Deprecated field [{}] used, this field is unused and will be removed entirely",
            new Object[] { prefix, removedName },
            removedName
        );

    }

    private static String parserLocation(String parserName, Supplier<XContentLocation> location) {
        return parserName == null ? "" : "[" + parserName + "][" + location.get() + "] ";
    }

    private static void log(boolean isCompatibleDeprecation, String message, Object[] params, String fieldName) {
        if (isCompatibleDeprecation) {
            deprecationLogger.compatibleCritical("deprecated_field_" + fieldName, message, params);
        } else {
            deprecationLogger.warn(DeprecationCategory.API, "deprecated_field_" + fieldName, message, params);
        }
    }
}