/*

 * Copyright (c) 2015, 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.

 *

 * 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 compiler.compilercontrol.share;

import java.io.FileNotFoundException;

import java.io.PrintStream;

import java.util.Objects;

import java.util.Stack;

/**

 * Simple JSON file writer

 */

public class JSONFile implements AutoCloseable {

    private final Stack<Element> stack;

    private final String fileName;

    private final PrintStream out;

    private int spaces;

    /**

     * JSON element

     */

    public enum Element {

        OBJECT,

        ARRAY,

        PAIR,

        VALUE

    }

    /**

     * Constructor. Creates file with default name

     */

    public JSONFile() {

        this("directives_file.json");

    }

    /**

     * Constructor

     *

     * @param fileName file name

     */

    public JSONFile(String fileName) {

        this.spaces = 0;

        this.stack = new Stack<>();

        this.fileName = fileName;

        try {

            out = new PrintStream(fileName);

        } catch (FileNotFoundException e) {

            throw new Error("TESTBUG: can't open/create file " + fileName, e);

        }

    }

    /**

     * Gets file name

     *

     * @return file name string

     */

    public String getFileName() {

        return fileName;

    }

    /**

     * Gets current JSON element in the file.

     * The element is a current {@linkplain Element}

     * that was written into a file.

     *

     * @return the type of the current element,

     * or null if there are nothing written

     */

    public Element getElement() {

        if (stack.empty()) {

            return null;

        }

        return stack.peek();

    }

    /**

     * Writes given type with a value to file.

     * Note that only PAIR and VALUE types accept a single value parameter.

     * OBJECT and ARRAY do not have a value

     *

     * @param element  JSON element type

     * @param value element's value

     * @return this file instance

     */

    public JSONFile write(Element element, String... value) {

        if (value.length > 1) {

            throw new Error("TESTBUG: Unexpected value length: "

                    + value.length);

        }

        if (!stack.empty()) {

            if (stack.peek() == Element.VALUE) {

                out.print(", ");

                stack.pop();

            }

        }

        switch (element) {

            case OBJECT:

                out.print("{");

                spaces++;

                stack.push(Element.VALUE);

                break;

            case ARRAY:

                out.print("[");

                stack.push(Element.VALUE);

                break;

            case PAIR:

                fillSpaces();

                Objects.requireNonNull(value, "TESTBUG: " + element

                        + "requires a value to be set");

                out.print(value[0] + ": ");

                break;

            case VALUE:

                Objects.requireNonNull(value, "TESTBUG: " + element

                        + "requires a value to be set");

                out.print(value[0]);

                break;

        }

        stack.push(element);

        return this;

    }

    private void fillSpaces() {

        out.println();

        for (int i = 0; i < spaces; i++) {

            // Fill with spaces to be more readable

            out.print("  ");

        }

    }

    /**

     * Ends current object or array of {@linkplain Element}

     *

     * @return this file instance

     */

    public JSONFile end() {

        if (!stack.empty()) {

            Element prev = stack.pop();

            while (prev != Element.OBJECT && prev != Element.ARRAY

                    && !stack.empty()) {

                prev = stack.pop();

            }

            switch (prev) {

                case OBJECT:

                    spaces--;

                    fillSpaces();

                    out.print("}");

                    break;

                case ARRAY:

                    out.print("]");

                    break;

                default:

                    throw new Error("TESTBUG: Incorrect end. " +

                            "Wrong type found: " + prev);

            }

        } else {

            throw new Error("TESTBUG: Incorrect end. Empty stack");

        }

        return this;

    }

    /**

     * Closes this file

     */

    @Override

    public void close() {

        out.close();

    }

}