/*
* The MIT License
*
* Copyright (c) 2011, Oracle Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.util;

import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONFunction;
import net.sf.json.JSONNull;
import net.sf.json.JSONObject;
import net.sf.json.JSONString;
import net.sf.json.util.JSONUtils;

/**
 * Json utils for canonical writing.
 */
public class JSONCanonicalUtils {
    /**
     * Write JSON object to writer in canonical form.
     *
     * @param json JSONObject
     * @param writer Writer
     * @throws IOException if any
     */
    public static void write(JSONObject json, Writer writer) throws IOException {

        if (json.isNullObject()) {
            writer.write(JSONNull.getInstance().toString());
            return;
        }

        boolean b = false;
        Iterator keys = json.keys();
        writer.write('{');

        while (keys.hasNext()) {
            if (b) {
                writer.write(',');
            }
            Object k = keys.next();
            writer.write(JSONUtils.quote(k.toString()));
            writer.write(':');
            Object v = json.get(k);
            if (v instanceof JSON) {
                write((JSON) v, writer);
            } else {
                writer.write(toCanonical(v));
            }
            b = true;
        }
        writer.write('}');
    }

    /**
     * Write JSON array to writer in canonical form.
     *
     * @param json JSONArray
     * @param writer Writer
     * @throws IOException
     */
    public static void write(JSONArray json, Writer writer) throws IOException {
        boolean b = false;
        int len = json.size();
        writer.write('[');
        for (int i = 0; i < len; i += 1) {
            if (b) {
                writer.write(',');
            }
            Object v = json.get(i);
            if (v instanceof JSON) {
                write((JSON) v, writer);
            } else {
                writer.write(toCanonical(v));
            }
            b = true;
        }
        writer.write(']');
    }

    private static void write(JSON o, Writer writer) throws IOException {
        if (o instanceof JSONObject) {
            write((JSONObject) o, writer);
        } else if (o instanceof JSONArray) {
            write((JSONArray) o, writer);
        }
    }

    private static String toCanonical(Object value) throws IOException {
        if (value == null || JSONUtils.isNull(value)) {
            return "null";
        }
        if (value instanceof JSONFunction) {
            return value.toString();
        }
        if (value instanceof JSONString) {
            return ((JSONString) value).toJSONString();
        }
        if (value instanceof Number) {
            return JSONUtils.numberToString((Number) value).toLowerCase();
        }
        if (value instanceof Boolean || value instanceof JSONObject || value instanceof JSONArray) {
            return value.toString();
        }
        return quoteCanonical(value.toString());
    }

    private static String quoteCanonical(String s) {
        if (s == null || s.length() == 0) {
            return "\"\"";
        }

        int len = s.length();
        StringBuilder sb = new StringBuilder(len + 4);

        sb.append('"');
        for (int i = 0; i < len; i += 1) {
            char c = s.charAt(i);
            switch (c) {
                case '\\':
                case '"':
                    sb.append('\\');
                    sb.append(c);
                    break;
                default:
                    if (c < ' ') {
                        String t = "000" + Integer.toHexString(c);
                        sb.append("\\u")
                            .append(t.substring(t.length() - 4));
                    } else {
                        sb.append(c);
                    }
            }
        }
        sb.append('"');
        return sb.toString();
    }
}