package fr.xephi.authme;

import com.google.common.base.Throwables;
import fr.xephi.authme.output.LogLevel;
import fr.xephi.authme.settings.Settings;
import fr.xephi.authme.settings.properties.PluginSettings;
import fr.xephi.authme.settings.properties.SecuritySettings;
import fr.xephi.authme.util.ExceptionUtils;

import java.io.Closeable;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
import java.text.MessageFormat;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.util.function.Supplier;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * AuthMe logger.
 */
public final class ConsoleLogger {

    private static final String NEW_LINE = System.getProperty("line.separator");
    /** Formatter which formats dates to something like "[08-16 21:18:46]" for any given LocalDateTime. */
    private static final DateTimeFormatter DATE_FORMAT = new DateTimeFormatterBuilder()
        .appendLiteral('[')
        .appendPattern("MM-dd HH:mm:ss")
        .appendLiteral(']')
        .toFormatter();

    // Outside references
    private static File logFile;
    private static Logger logger;

    // Shared state
    private static OutputStreamWriter fileWriter;

    // Individual state
    private final String name;
    private LogLevel logLevel = LogLevel.INFO;

    /**
     * Constructor.
     *
     * @param name the name of this logger (the fully qualified class name using it)
     */
    public ConsoleLogger(String name) {
        this.name = name;
    }

    // --------
    // Configurations
    // --------

    public static void initialize(Logger logger, File logFile) {
        ConsoleLogger.logger = logger;
        ConsoleLogger.logFile = logFile;
    }

    /**
     * Sets logging settings which are shared by all logger instances.
     *
     * @param settings the settings to read from
     */
    public static void initializeSharedSettings(Settings settings) {
        boolean useLogging = settings.getProperty(SecuritySettings.USE_LOGGING);
        if (useLogging) {
            initializeFileWriter();
        } else {
            closeFileWriter();
        }
    }

    /**
     * Sets logging settings which are individual to all loggers.
     *
     * @param settings the settings to read from
     */
    public void initializeSettings(Settings settings) {
        this.logLevel = settings.getProperty(PluginSettings.LOG_LEVEL);
    }

    public LogLevel getLogLevel() {
        return logLevel;
    }

    public String getName() {
        return name;
    }


    // --------
    // Logging methods
    // --------

    /**
     * Log a WARN message.
     *
     * @param message The message to log
     */
    public void warning(String message) {
        logger.warning(message);
        writeLog("[WARN] " + message);
    }

    /**
     * Log a Throwable with the provided message on WARNING level
     * and save the stack trace to the log file.
     *
     * @param message The message to accompany the exception
     * @param th      The Throwable to log
     */
    public void logException(String message, Throwable th) {
        warning(message + " " + ExceptionUtils.formatException(th));
        writeLog(Throwables.getStackTraceAsString(th));
    }

    /**
     * Log an INFO message.
     *
     * @param message The message to log
     */
    public void info(String message) {
        logger.info(message);
        writeLog("[INFO] " + message);
    }

    /**
     * Log a FINE message if enabled.
     * <p>
     * Implementation note: this logs a message on INFO level because
     * levels below INFO are disabled by Bukkit/Spigot.
     *
     * @param message The message to log
     */
    public void fine(String message) {
        if (logLevel.includes(LogLevel.FINE)) {
            logger.info(message);
            writeLog("[FINE] " + message);
        }
    }

    // --------
    // Debug log methods
    // --------

    /**
     * Log a DEBUG message if enabled.
     * <p>
     * Implementation note: this logs a message on INFO level and prefixes it with "DEBUG" because
     * levels below INFO are disabled by Bukkit/Spigot.
     *
     * @param message The message to log
     */
    public void debug(String message) {
        if (logLevel.includes(LogLevel.DEBUG)) {
            logAndWriteWithDebugPrefix(message);
        }
    }

    /**
     * Log the DEBUG message.
     *
     * @param message the message
     * @param param1 parameter to replace in the message
     */
    // Avoids array creation if DEBUG level is disabled
    public void debug(String message, Object param1) {
        if (logLevel.includes(LogLevel.DEBUG)) {
            debug(message, new Object[]{param1});
        }
    }

    /**
     * Log the DEBUG message.
     *
     * @param message the message
     * @param param1 first param to replace in message
     * @param param2 second param to replace in message
     */
    // Avoids array creation if DEBUG level is disabled
    public void debug(String message, Object param1, Object param2) {
        if (logLevel.includes(LogLevel.DEBUG)) {
            debug(message, new Object[]{param1, param2});
        }
    }

    /**
     * Log the DEBUG message.
     *
     * @param message the message
     * @param params the params to replace in the message
     */
    public void debug(String message, Object... params) {
        if (logLevel.includes(LogLevel.DEBUG)) {
            logAndWriteWithDebugPrefix(MessageFormat.format(message, params));
        }
    }

    /**
     * Log the DEBUG message from the supplier if enabled.
     *
     * @param msgSupplier the message supplier
     */
    public void debug(Supplier<String> msgSupplier) {
        if (logLevel.includes(LogLevel.DEBUG)) {
            logAndWriteWithDebugPrefix(msgSupplier.get());
        }
    }

    private void logAndWriteWithDebugPrefix(String message) {
        String debugMessage = "[DEBUG] " + message;
        logger.info(debugMessage);
        writeLog(debugMessage);
    }

    // --------
    // Helpers
    // --------

    /**
     * Closes the file writer.
     */
    public static void closeFileWriter() {
        if (fileWriter != null) {
            try {
                fileWriter.flush();
            } catch (IOException ignored) {
            } finally {
                closeSafely(fileWriter);
                fileWriter = null;
            }
        }
    }

    /**
     * Write a message into the log file with a TimeStamp if enabled.
     *
     * @param message The message to write to the log
     */
    private static void writeLog(String message) {
        if (fileWriter != null) {
            String dateTime = DATE_FORMAT.format(LocalDateTime.now());
            try {
                fileWriter.write(dateTime);
                fileWriter.write(": ");
                fileWriter.write(message);
                fileWriter.write(NEW_LINE);
                fileWriter.flush();
            } catch (IOException ignored) {
            }
        }
    }

    private static void closeSafely(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
                logger.log(Level.SEVERE, "Failed to close resource", e);
            }
        }
    }

    /**
     * Populates the {@link #fileWriter} field if it is null, handling any exceptions that might
     * arise during its creation.
     */
    private static void initializeFileWriter() {
        if (fileWriter == null) {
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(logFile, true);
                fileWriter = new OutputStreamWriter(fos, StandardCharsets.UTF_8);
            } catch (Exception e) {
                closeSafely(fos);
                logger.log(Level.SEVERE, "Failed to create writer to AuthMe log file", e);
            }
        }
    }
}