/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.logging;

import static java.lang.String.format;
import static org.apache.commons.text.StringEscapeUtils.escapeJava;

import java.io.PrintStream;
import java.util.Arrays;
import java.util.IllegalFormatException;
import java.util.Iterator;
import java.util.Queue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.function.Function;

public class AssertableLogProvider extends AbstractLogProvider<InternalLog> {
    private final boolean debugEnabled;
    private final Queue<LogCall> logCalls = new LinkedBlockingQueue<>();

    public AssertableLogProvider() {
        this(false);
    }

    public AssertableLogProvider(boolean debugEnabled) {
        this.debugEnabled = debugEnabled;
    }

    public void print(PrintStream out) {
        for (LogCall call : logCalls) {
            out.println(call.toLogLikeString());
            if (call.throwable != null) {
                call.throwable.printStackTrace(out);
            }
        }
    }

    public Queue<LogCall> getLogCalls() {
        return logCalls;
    }

    public enum Level {
        DEBUG,
        INFO,
        WARN,
        ERROR
    }

    static final class LogCall {
        private final String context;
        private final Level level;
        private final String message;
        private final Object[] arguments;
        private final Throwable throwable;

        private LogCall(String context, Level level, String message, Object[] arguments, Throwable throwable) {
            this.level = level;
            this.context = context;
            this.message = message;
            this.arguments = arguments;
            this.throwable = throwable;
        }

        String getContext() {
            return context;
        }

        Level getLevel() {
            return level;
        }

        String getMessage() {
            return message;
        }

        Object[] getArguments() {
            return arguments;
        }

        Throwable getThrowable() {
            return throwable;
        }

        @Override
        public String toString() {
            StringBuilder builder = new StringBuilder("LogCall{");
            builder.append(context);
            builder.append(' ');
            builder.append(level);
            builder.append(", message=");
            if (message != null) {
                builder.append('\'').append(escapeJava(message)).append('\'');
            } else {
                builder.append("null");
            }
            builder.append(", arguments=");
            if (arguments != null) {
                builder.append('[');
                boolean first = true;
                for (Object arg : arguments) {
                    if (!first) {
                        builder.append(',');
                    }
                    first = false;
                    builder.append(escapeJava(String.valueOf(arg)));
                }
                builder.append(']');
            } else {
                builder.append("null");
            }
            builder.append(", throwable=");
            if (throwable != null) {
                builder.append('\'').append(escapeJava(throwable.toString())).append('\'');
            } else {
                builder.append("null");
            }
            builder.append('}');
            return builder.toString();
        }

        String toLogLikeString() {
            String msg;
            if (arguments != null) {
                try {
                    msg = format(message, arguments);
                } catch (IllegalFormatException e) {
                    msg = format("IllegalFormat{message: \"%s\", arguments: %s}", message, Arrays.toString(arguments));
                }
            } else {
                msg = message;
            }
            if (throwable != null) {
                msg = msg + " cause " + throwable;
            }
            return format("%s @ %s: %s", level, context, msg);
        }
    }

    protected class AssertableLog implements InternalLog {
        private final String context;

        AssertableLog(String context) {
            this.context = context;
        }

        @Override
        public boolean isDebugEnabled() {
            return debugEnabled;
        }

        @Override
        public void debug(String message) {
            logCalls.add(new LogCall(context, Level.DEBUG, message, null, null));
        }

        @Override
        public void debug(String message, Throwable throwable) {
            logCalls.add(new LogCall(context, Level.DEBUG, message, null, throwable));
        }

        @Override
        public void debug(String format, Object... arguments) {
            logCalls.add(new LogCall(context, Level.DEBUG, format, arguments, null));
        }

        @Override
        public void info(String message) {
            logCalls.add(new LogCall(context, Level.INFO, message, null, null));
        }

        @Override
        public void info(String message, Throwable throwable) {
            logCalls.add(new LogCall(context, Level.INFO, message, null, throwable));
        }

        @Override
        public void info(String format, Object... arguments) {
            logCalls.add(new LogCall(context, Level.INFO, format, arguments, null));
        }

        @Override
        public void warn(String message) {
            logCalls.add(new LogCall(context, Level.WARN, message, null, null));
        }

        @Override
        public void warn(String message, Throwable throwable) {
            logCalls.add(new LogCall(context, Level.WARN, message, null, throwable));
        }

        @Override
        public void warn(String format, Object... arguments) {
            logCalls.add(new LogCall(context, Level.WARN, format, arguments, null));
        }

        @Override
        public void error(String message) {
            logCalls.add(new LogCall(context, Level.ERROR, message, null, null));
        }

        @Override
        public void error(String message, Throwable throwable) {
            logCalls.add(new LogCall(context, Level.ERROR, message, null, throwable));
        }

        @Override
        public void error(String format, Object... arguments) {
            logCalls.add(new LogCall(context, Level.ERROR, format, arguments, null));
        }

        @Override
        public void debug(Neo4jLogMessage message) {
            logCalls.add(new LogCall(context, Level.DEBUG, message.getFormattedMessage(), null, null));
        }

        @Override
        public void debug(Neo4jMessageSupplier supplier) {
            logCalls.add(new LogCall(context, Level.DEBUG, supplier.get().getFormattedMessage(), null, null));
        }

        @Override
        public void info(Neo4jLogMessage message) {
            logCalls.add(new LogCall(context, Level.INFO, message.getFormattedMessage(), null, null));
        }

        @Override
        public void info(Neo4jMessageSupplier supplier) {
            logCalls.add(new LogCall(context, Level.INFO, supplier.get().getFormattedMessage(), null, null));
        }

        @Override
        public void warn(Neo4jLogMessage message) {
            logCalls.add(new LogCall(context, Level.WARN, message.getFormattedMessage(), null, null));
        }

        @Override
        public void warn(Neo4jMessageSupplier supplier) {
            logCalls.add(new LogCall(context, Level.WARN, supplier.get().getFormattedMessage(), null, null));
        }

        @Override
        public void error(Neo4jLogMessage message) {
            logCalls.add(new LogCall(context, Level.ERROR, message.getFormattedMessage(), null, null));
        }

        @Override
        public void error(Neo4jMessageSupplier supplier) {
            logCalls.add(new LogCall(context, Level.ERROR, supplier.get().getFormattedMessage(), null, null));
        }

        @Override
        public void error(Neo4jLogMessage message, Throwable throwable) {
            logCalls.add(new LogCall(context, Level.ERROR, message.getFormattedMessage(), null, throwable));
        }
    }

    @Override
    protected InternalLog buildLog(Class<?> loggingClass) {
        return new AssertableLog(loggingClass.getName());
    }

    @Override
    protected InternalLog buildLog(String context) {
        return new AssertableLog(context);
    }

    /**
     * Clear this logger for re-use.
     */
    public void clear() {
        logCalls.clear();
    }

    public String serialize() {
        return serialize0(logCalls.iterator(), LogCall::toLogLikeString);
    }

    private static String serialize0(Iterator<LogCall> events, Function<LogCall, String> serializer) {
        StringBuilder sb = new StringBuilder();
        while (events.hasNext()) {
            sb.append(serializer.apply(events.next()));
            sb.append('\n');
        }
        return sb.toString();
    }
}
