/*
 * Copyright 2015-2020 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.dv8tion.jda.internal.utils;

import org.slf4j.helpers.FormattingTuple;
import org.slf4j.helpers.MarkerIgnoringBase;
import org.slf4j.helpers.MessageFormatter;
import org.slf4j.helpers.Util;
import org.slf4j.spi.LocationAwareLogger;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.PrintStream;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Properties;

class SimpleLogger extends MarkerIgnoringBase {

    private static final long serialVersionUID = -632788891211436180L;
    private static final String CONFIGURATION_FILE = "Loggerger.properties";

    private static long START_TIME = System.currentTimeMillis();
    private static final Properties SIMPLE_LOGGER_PROPS = new Properties();

    private static final int LOG_LEVEL_TRACE = LocationAwareLogger.TRACE_INT;
    private static final int LOG_LEVEL_DEBUG = LocationAwareLogger.DEBUG_INT;
    private static final int LOG_LEVEL_INFO = LocationAwareLogger.INFO_INT;
    private static final int LOG_LEVEL_WARN = LocationAwareLogger.WARN_INT;
    private static final int LOG_LEVEL_ERROR = LocationAwareLogger.ERROR_INT;

    private static boolean INITIALIZED = false;

    private static int DEFAULT_LOG_LEVEL = LOG_LEVEL_INFO;
    private static boolean SHOW_DATE_TIME = false;
    private static String DATE_TIME_FORMAT_STR = null;
    private static DateFormat DATE_FORMATTER = null;
    private static boolean SHOW_THREAD_NAME = true;
    private static boolean SHOW_LOG_NAME = true;
    private static boolean SHOW_SHORT_LOG_NAME = false;
    private static String LOG_FILE = "System.err";
    private static PrintStream TARGET_STREAM = null;
    private static boolean LEVEL_IN_BRACKETS = false;
    private static String WARN_LEVEL_STRING = "WARN";

    public static final String SYSTEM_PREFIX = "org.slf4j.Loggerger.";

    public static final String DEFAULT_LOG_LEVEL_KEY = SYSTEM_PREFIX + "defaultLogLevel";
    public static final String SHOW_DATE_TIME_KEY = SYSTEM_PREFIX + "showDateTime";
    public static final String DATE_TIME_FORMAT_KEY = SYSTEM_PREFIX + "dateTimeFormat";
    public static final String SHOW_THREAD_NAME_KEY = SYSTEM_PREFIX + "showThreadName";
    public static final String SHOW_LOG_NAME_KEY = SYSTEM_PREFIX + "showLogName";
    public static final String SHOW_SHORT_LOG_NAME_KEY = SYSTEM_PREFIX + "showShortLogName";
    public static final String LOG_FILE_KEY = SYSTEM_PREFIX + "logFile";
    public static final String LEVEL_IN_BRACKETS_KEY = SYSTEM_PREFIX + "levelInBrackets";
    public static final String WARN_LEVEL_STRING_KEY = SYSTEM_PREFIX + "warnLevelString";

    public static final String LOG_KEY_PREFIX = SYSTEM_PREFIX + "log.";

    private static String getStringProperty(String name) {
        String prop = null;
        try {
            prop = System.getProperty(name);
        } catch (SecurityException e) {
            ; // Ignore
        }
        return (prop == null) ? SIMPLE_LOGGER_PROPS.getProperty(name) : prop;
    }

    private static String getStringProperty(String name, String defaultValue) {
        String prop = getStringProperty(name);
        return (prop == null) ? defaultValue : prop;
    }

    private static boolean getBooleanProperty(String name, boolean defaultValue) {
        String prop = getStringProperty(name);
        return (prop == null) ? defaultValue : "true".equalsIgnoreCase(prop);
    }

    static void init() {
        INITIALIZED = true;
        loadProperties();

        String defaultLogLevelString = getStringProperty(DEFAULT_LOG_LEVEL_KEY, null);
        if (defaultLogLevelString != null)
            DEFAULT_LOG_LEVEL = stringToLevel(defaultLogLevelString);

        SHOW_LOG_NAME = getBooleanProperty(SHOW_LOG_NAME_KEY, SHOW_LOG_NAME);
        SHOW_SHORT_LOG_NAME = getBooleanProperty(SHOW_SHORT_LOG_NAME_KEY, SHOW_SHORT_LOG_NAME);
        SHOW_DATE_TIME = getBooleanProperty(SHOW_DATE_TIME_KEY, SHOW_DATE_TIME);
        SHOW_THREAD_NAME = getBooleanProperty(SHOW_THREAD_NAME_KEY, SHOW_THREAD_NAME);
        DATE_TIME_FORMAT_STR = getStringProperty(DATE_TIME_FORMAT_KEY, DATE_TIME_FORMAT_STR);
        LEVEL_IN_BRACKETS = getBooleanProperty(LEVEL_IN_BRACKETS_KEY, LEVEL_IN_BRACKETS);
        WARN_LEVEL_STRING = getStringProperty(WARN_LEVEL_STRING_KEY, WARN_LEVEL_STRING);

        LOG_FILE = getStringProperty(LOG_FILE_KEY, LOG_FILE);
        TARGET_STREAM = computeTargetStream(LOG_FILE);

        if (DATE_TIME_FORMAT_STR != null) {
            try {
                DATE_FORMATTER = new SimpleDateFormat(DATE_TIME_FORMAT_STR);
            } catch (IllegalArgumentException e) {
                Util.report("Bad date format in " + CONFIGURATION_FILE + "; will output relative time", e);
            }
        }
    }

    private static PrintStream computeTargetStream(String logFile) {
        if ("System.err".equalsIgnoreCase(logFile))
            return System.err;
        else if ("System.out".equalsIgnoreCase(logFile)) {
            return System.out;
        } else {
            try {
                FileOutputStream fos = new FileOutputStream(logFile);
                PrintStream printStream = new PrintStream(fos);
                return printStream;
            } catch (FileNotFoundException e) {
                Util.report("Could not open [" + logFile + "]. Defaulting to System.err", e);
                return System.err;
            }
        }
    }

    private static void loadProperties() {
        // Add props from the resource Loggerger.properties
        InputStream in = AccessController.doPrivileged(new PrivilegedAction<InputStream>() {
            public InputStream run() {
                ClassLoader threadCL = Thread.currentThread().getContextClassLoader();
                if (threadCL != null) {
                    return threadCL.getResourceAsStream(CONFIGURATION_FILE);
                } else {
                    return ClassLoader.getSystemResourceAsStream(CONFIGURATION_FILE);
                }
            }
        });
        if (null != in) {
            try {
                SIMPLE_LOGGER_PROPS.load(in);
                in.close();
            } catch (java.io.IOException e) {
                // ignored
            }
        }
    }

    protected int currentLogLevel = LOG_LEVEL_INFO;
    private transient String shortLogName = null;

    SimpleLogger(String name) {
        if (!INITIALIZED) {
            init();
        }
        this.name = name;

        String levelString = recursivelyComputeLevelString();
        if (levelString != null) {
            this.currentLogLevel = stringToLevel(levelString);
        } else {
            this.currentLogLevel = DEFAULT_LOG_LEVEL;
        }
    }

    String recursivelyComputeLevelString() {
        String tempName = name;
        String levelString = null;
        int indexOfLastDot = tempName.length();
        while ((levelString == null) && (indexOfLastDot > -1)) {
            tempName = tempName.substring(0, indexOfLastDot);
            levelString = getStringProperty(LOG_KEY_PREFIX + tempName, null);
            indexOfLastDot = String.valueOf(tempName).lastIndexOf(".");
        }
        return levelString;
    }

    private static int stringToLevel(String levelStr) {
        if ("trace".equalsIgnoreCase(levelStr)) {
            return LOG_LEVEL_TRACE;
        } else if ("debug".equalsIgnoreCase(levelStr)) {
            return LOG_LEVEL_DEBUG;
        } else if ("info".equalsIgnoreCase(levelStr)) {
            return LOG_LEVEL_INFO;
        } else if ("warn".equalsIgnoreCase(levelStr)) {
            return LOG_LEVEL_WARN;
        } else if ("error".equalsIgnoreCase(levelStr)) {
            return LOG_LEVEL_ERROR;
        }
        // assume INFO by default
        return LOG_LEVEL_INFO;
    }

    private void log(int level, String message, Throwable t) {
        if (!isLevelEnabled(level)) {
            return;
        }

        StringBuilder buf = new StringBuilder(32);

        // Append date-time if so configured
        if (SHOW_DATE_TIME) {
            if (DATE_FORMATTER != null) {
                buf.append(getFormattedDate());
                buf.append(' ');
            } else {
                buf.append(System.currentTimeMillis() - START_TIME);
                buf.append(' ');
            }
        }

        // Append current thread name if so configured
        if (SHOW_THREAD_NAME) {
            buf.append('[');
            buf.append(Thread.currentThread().getName());
            buf.append("] ");
        }

        if (LEVEL_IN_BRACKETS)
            buf.append('[');

        // Append a readable representation of the log level
        switch (level) {
            case LOG_LEVEL_TRACE:
                buf.append("TRACE");
                break;
            case LOG_LEVEL_DEBUG:
                buf.append("DEBUG");
                break;
            case LOG_LEVEL_INFO:
                buf.append("INFO");
                break;
            case LOG_LEVEL_WARN:
                buf.append(WARN_LEVEL_STRING);
                break;
            case LOG_LEVEL_ERROR:
                buf.append("ERROR");
                break;
        }
        if (LEVEL_IN_BRACKETS)
            buf.append(']');
        buf.append(' ');

        // Append the name of the log instance if so configured
        if (SHOW_SHORT_LOG_NAME) {
            if (shortLogName == null)
                shortLogName = computeShortName();
            buf.append(String.valueOf(shortLogName)).append(" - ");
        } else if (SHOW_LOG_NAME) {
            buf.append(String.valueOf(name)).append(" - ");
        }

        // Append the message
        buf.append(message);

        write(buf, t);

    }

    void write(StringBuilder buf, Throwable t) {
        TARGET_STREAM.println(buf.toString());
        if (t != null) {
            t.printStackTrace(TARGET_STREAM);
        }
        TARGET_STREAM.flush();
    }

    private String getFormattedDate() {
        Date now = new Date();
        String dateText;
        synchronized (DATE_FORMATTER) {
            dateText = DATE_FORMATTER.format(now);
        }
        return dateText;
    }

    private String computeShortName() {
        return name.substring(name.lastIndexOf(".") + 1);
    }

    private void formatAndLog(int level, String format, Object arg1, Object arg2) {
        if (!isLevelEnabled(level)) {
            return;
        }
        FormattingTuple tp = MessageFormatter.format(format, arg1, arg2);
        log(level, tp.getMessage(), tp.getThrowable());
    }

    private void formatAndLog(int level, String format, Object... arguments) {
        if (!isLevelEnabled(level)) {
            return;
        }
        FormattingTuple tp = MessageFormatter.arrayFormat(format, arguments);
        log(level, tp.getMessage(), tp.getThrowable());
    }

    protected boolean isLevelEnabled(int logLevel) {
        // log level are numerically ordered so can use simple numeric
        // comparison
        return (logLevel >= currentLogLevel);
    }

    public boolean isTraceEnabled() {
        return isLevelEnabled(LOG_LEVEL_TRACE);
    }

    public void trace(String msg) {
        log(LOG_LEVEL_TRACE, msg, null);
    }

    public void trace(String format, Object param1) {
        formatAndLog(LOG_LEVEL_TRACE, format, param1, null);
    }

    public void trace(String format, Object param1, Object param2) {
        formatAndLog(LOG_LEVEL_TRACE, format, param1, param2);
    }

    public void trace(String format, Object... argArray) {
        formatAndLog(LOG_LEVEL_TRACE, format, argArray);
    }

    public void trace(String msg, Throwable t) {
        log(LOG_LEVEL_TRACE, msg, t);
    }

    public boolean isDebugEnabled() {
        return isLevelEnabled(LOG_LEVEL_DEBUG);
    }

    public void debug(String msg) {
        log(LOG_LEVEL_DEBUG, msg, null);
    }

    public void debug(String format, Object param1) {
        formatAndLog(LOG_LEVEL_DEBUG, format, param1, null);
    }

    public void debug(String format, Object param1, Object param2) {
        formatAndLog(LOG_LEVEL_DEBUG, format, param1, param2);
    }

    public void debug(String format, Object... argArray) {
        formatAndLog(LOG_LEVEL_DEBUG, format, argArray);
    }

    public void debug(String msg, Throwable t) {
        log(LOG_LEVEL_DEBUG, msg, t);
    }

    public boolean isInfoEnabled() {
        return isLevelEnabled(LOG_LEVEL_INFO);
    }

    public void info(String msg) {
        log(LOG_LEVEL_INFO, msg, null);
    }

    public void info(String format, Object arg) {
        formatAndLog(LOG_LEVEL_INFO, format, arg, null);
    }

    public void info(String format, Object arg1, Object arg2) {
        formatAndLog(LOG_LEVEL_INFO, format, arg1, arg2);
    }

    public void info(String format, Object... argArray) {
        formatAndLog(LOG_LEVEL_INFO, format, argArray);
    }

    public void info(String msg, Throwable t) {
        log(LOG_LEVEL_INFO, msg, t);
    }

    public boolean isWarnEnabled() {
        return isLevelEnabled(LOG_LEVEL_WARN);
    }

    public void warn(String msg) {
        log(LOG_LEVEL_WARN, msg, null);
    }

    public void warn(String format, Object arg) {
        formatAndLog(LOG_LEVEL_WARN, format, arg, null);
    }

    public void warn(String format, Object arg1, Object arg2) {
        formatAndLog(LOG_LEVEL_WARN, format, arg1, arg2);
    }

    public void warn(String format, Object... argArray) {
        formatAndLog(LOG_LEVEL_WARN, format, argArray);
    }

    public void warn(String msg, Throwable t) {
        log(LOG_LEVEL_WARN, msg, t);
    }

    public boolean isErrorEnabled() {
        return isLevelEnabled(LOG_LEVEL_ERROR);
    }

    public void error(String msg) {
        log(LOG_LEVEL_ERROR, msg, null);
    }

    public void error(String format, Object arg) {
        formatAndLog(LOG_LEVEL_ERROR, format, arg, null);
    }

    public void error(String format, Object arg1, Object arg2) {
        formatAndLog(LOG_LEVEL_ERROR, format, arg1, arg2);
    }

    public void error(String format, Object... argArray) {
        formatAndLog(LOG_LEVEL_ERROR, format, argArray);
    }

    public void error(String msg, Throwable t) {
        log(LOG_LEVEL_ERROR, msg, t);
    }
}