package org.example;

import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.classic.spi.Configurator;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.Appender;
import ch.qos.logback.core.ConsoleAppender;
import ch.qos.logback.core.Context;
import ch.qos.logback.core.FileAppender;
import ch.qos.logback.core.joran.util.PropertySetter;
import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.ContextAwareBase;
import ch.qos.logback.core.spi.LifeCycle;
import ch.qos.logback.core.util.DynamicClassLoadingException;
import ch.qos.logback.core.util.FileSize;
import ch.qos.logback.core.util.IncompatibleClassException;
import ch.qos.logback.core.util.OptionHelper;
import java.io.File;
import java.nio.file.Path;

/**
 * Configures logging. We do it this way because reading the XML files is really
 * slow (over half a second on startup).
 *
 * @author thomas
 */
public class LogbackConfigurator extends ContextAwareBase implements Configurator {

    @Override
    public void configure(LoggerContext context) {
        Level level;
        Appender<ILoggingEvent> appender;
        if (Main.isDevelopmentEnvironment()) {
            level = Level.INFO;
            appender = devAppender(context);
        } else {
            level = Level.INFO;
            var logDir = Main.appDirectory().resolve("logs");
            appender = prodAppender(context, logDir);
        }
        var root = context.getLogger(Logger.ROOT_LOGGER_NAME);
        root.setLevel(level);
        root.addAppender(appender);
    }

    private static Appender<ILoggingEvent> devAppender(LoggerContext context) {
        var console = new ConsoleAppender<ILoggingEvent>();
        console.setContext(context);
        console.setName("STDOUT");
        console.setEncoder(encoder(context));
        console.start();
        return console;
    }

    private static Appender<ILoggingEvent> prodAppender(LoggerContext context, Path logDir) {
        // Package ch.qos.logback.core.rolling is not exported, so we have to resort to reflection hacks.
        // See: https://jira.qos.ch/browse/LOGBACK-1385
        try {
            var cacheClassName = "ch.qos.logback.core.joran.util.beans.BeanDescriptionCache";
            var cache = OptionHelper.instantiateByClassNameAndParameter(cacheClassName, Object.class, context, Context.class, context);

            var setterParams = new Class<?>[]{cache.getClass(), Object.class};
            var setterConstructor = PropertySetter.class.getConstructor(setterParams);

            var rollingClassName = "ch.qos.logback.core.rolling.RollingFileAppender";
            @SuppressWarnings("unchecked")
            var rolling = (FileAppender<ILoggingEvent>) OptionHelper.instantiateByClassName(rollingClassName, FileAppender.class, context);
            var rollingSetter = setterConstructor.newInstance(cache, rolling);
            rollingSetter.setContext(context);

            rolling.setContext(context);
            rolling.setName("ROLLING");

            var policyClassName = "ch.qos.logback.core.rolling.TimeBasedRollingPolicy";
            var policy = (ContextAware & LifeCycle) OptionHelper.instantiateByClassName(policyClassName, ContextAware.class, context);
            var policySetter = setterConstructor.newInstance(cache, policy);
            policySetter.setContext(context);

            policy.setContext(context);
            // rolling policies need to know their parent
            // it's one of the rare cases, where a sub-component knows about its parent
            policySetter.setComplexProperty("parent", rolling);

            var pattern = "%d{yyyy-MM-dd}.log.zip";
            policySetter.setComplexProperty("fileNamePattern", logDir.toString() + File.separatorChar + pattern);
            policySetter.setProperty("maxHistory", "3");
            policySetter.setComplexProperty("totalSizeCap", FileSize.valueOf("10MB"));
            policySetter.setProperty("cleanHistoryOnStart", "true");
            policy.start();

            rollingSetter.setComplexProperty("rollingPolicy", policy);
            rolling.setEncoder(encoder(context));
            rolling.start();
            return rolling;
        } catch (IncompatibleClassException | DynamicClassLoadingException | ReflectiveOperationException ex) {
            throw new RuntimeException(ex);
        }
    }

    private static PatternLayoutEncoder encoder(LoggerContext context) {
        var encoder = new PatternLayoutEncoder();
        encoder.setContext(context);
        encoder.setPattern("%d{yyyy-MM-dd'T'HH:mm:ss.SSSZ} [%thread] %-5level %logger{36} - %msg%n");
        encoder.start();
        return encoder;
    }
}