/*

 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jfr.internal.cmd;

import java.io.IOException;

import java.io.PrintWriter;

import java.nio.file.Path;

import jdk.jfr.EventType;

import jdk.jfr.ValueDescriptor;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.consumer.RecordedObject;

import jdk.jfr.consumer.RecordingFile;

final class JSONWriter extends StructuredWriter {

    public JSONWriter(PrintWriter writer) {

        super(writer);

    }

    public void print(Path source) throws IOException {

        try (RecordingFile es = new RecordingFile(source)) {

            printObjectBegin();

            printRecording(es);

            printObjectEnd();

            flush();

        }

    }

    private void printRecording(RecordingFile es) throws IOException {

        printDataStructureName("recording");

        printObjectBegin();

        printEvents(es);

        printObjectEnd();

    }

    private void printEvents(RecordingFile es) throws IOException {

        printDataStructureName("events");

        printArrayBegin();

        boolean first = true;

        while (es.hasMoreEvents()) {

            RecordedEvent e = es.readEvent();

            printNewDataStructure(first, true, null);

            printEvent(e);

            flush();

            first = false;

        }

        printArrayEnd();

    }

    private void printEvent(RecordedEvent e) {

        printObjectBegin();

        EventType type = e.getEventType();

        printValue(true, false, "name", type.getName());

        printValue(false, false, "typeId", type.getId());

        printValue(false, false, "startTime", e.getStartTime());

        printValue(false, false, "duration", e.getDuration());

        printNewDataStructure(false, false, "values");

        printObject(e);

        printObjectEnd();

    }

    void printValue(boolean first, boolean arrayElement, String name, Object value) {

        printNewDataStructure(first, arrayElement, name);

        if (!printIfNull(value)) {

            if (value instanceof Boolean) {

                printAsString(value);

                return;

            }

            if (value instanceof Double) {

                Double dValue = (Double) value;

                if (Double.isNaN(dValue) || Double.isInfinite(dValue)) {

                    printNull();

                    return;

                }

                printAsString(value);

                return;

            }

            if (value instanceof Float) {

                Float fValue = (Float) value;

                if (Float.isNaN(fValue) || Float.isInfinite(fValue)) {

                    printNull();

                    return;

                }

                printAsString(value);

                return;

            }

            if (value instanceof Number) {

                printAsString(value);

                return;

            }

            print("\"");

            printEscaped(String.valueOf(value));

            print("\"");

        }

    }

    public void printObject(RecordedObject object) {

        printObjectBegin();

        boolean first = true;

        for (ValueDescriptor v : object.getFields()) {

            printValueDescriptor(first, false, v, object.getValue(v.getName()));

            first = false;

        }

        printObjectEnd();

    }

    private void printArray(ValueDescriptor v, Object[] array) {

        printArrayBegin();

        boolean first = true;

        for (Object arrayElement : array) {

            printValueDescriptor(first, true, v, arrayElement);

            first = false;

        }

        printArrayEnd();

    }

    private void printValueDescriptor(boolean first, boolean arrayElement, ValueDescriptor vd, Object value) {

        if (vd.isArray() && !arrayElement) {

            printNewDataStructure(first, arrayElement, vd.getName());

            if (!printIfNull(value)) {

                printArray(vd, (Object[]) value);

            }

            return;

        }

        if (!vd.getFields().isEmpty()) {

            printNewDataStructure(first, arrayElement, vd.getName());

            if (!printIfNull(value)) {

                printObject((RecordedObject) value);

            }

            return;

        }

        printValue(first, arrayElement, vd.getName(), value);

    }

    private void printNewDataStructure(boolean first, boolean arrayElement, String name) {

        if (!first) {

            print(", ");

            if (!arrayElement) {

                println();

            }

        }

        if (!arrayElement) {

            printDataStructureName(name);

        }

    }

    private boolean printIfNull(Object value) {

        if (value == null) {

            printNull();

            return true;

        }

        return false;

    }

    private void printNull() {

        print("null");

    }

    private void printDataStructureName(String text) {

        printIndent();

        print("\"");

        print(text);

        print("\": ");

    }

    private void printObjectEnd() {

        retract();

        println();

        printIndent();

        print("}");

    }

    private void printObjectBegin() {

        println("{");

        indent();

    }

    private void printArrayEnd() {

        print("]");

    }

    private void printArrayBegin() {

        print("[");

    }

    private void printEscaped(String text) {

        for (int i = 0; i < text.length(); i++) {

            printEscaped(text.charAt(i));

        }

    }

    private void printEscaped(char c) {

        if (c == '\b') {

            print("\\b");

            return;

        }

        if (c == '\n') {

            print("\\n");

            return;

        }

        if (c == '\t') {

            print("\\t");

            return;

        }

        if (c == '\f') {

            print("\\f");

            return;

        }

        if (c == '\r') {

            print("\\r");

            return;

        }

        if (c == '\"') {

            print("\\\"");

            return;

        }

        if (c == '\\') {

            print("\\\\");

            return;

        }

        if (c == '/') {

            print("\\/");

            return;

        }

        if (c > 0x7F || c < 32) {

            print("\\u");

            // 0x10000 will pad with zeros.

            print(Integer.toHexString(0x10000 + (int) c).substring(1));

            return;

        }

        print(c);

    }

}