/*****************************************************************
 *   Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    https://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 ****************************************************************/

package org.apache.cayenne.wocompat;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;

import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.wocompat.parser.Parser;

/**
 * A <b>PropertyListSerialization</b> is a utility class that reads and stores
 * files in NeXT/Apple property list format. Unlike corresponding WebObjects
 * class, <code>PropertyListSerialization</code> uses standard Java collections
 * (lists and maps) to store property lists.
 * 
 */
public class PropertyListSerialization {

	/**
	 * Reads a property list file. Returns a property list object, that is
	 * normally a java.util.List or a java.util.Map, but can also be a String or
	 * a Number.
	 */
	public static Object propertyListFromFile(File f) throws FileNotFoundException {
		return propertyListFromFile(f, null);
	}

	/**
	 * Reads a property list file. Returns a property list object, that is
	 * normally a java.util.List or a java.util.Map, but can also be a String or
	 * a Number.
	 */
	public static Object propertyListFromFile(File f, PlistDataStructureFactory factory) throws FileNotFoundException {
		if (!f.isFile()) {
			throw new FileNotFoundException("No such file: " + f);
		}

		return new Parser(f, factory).propertyList();
	}

	/**
	 * Reads a property list data from InputStream. Returns a property list o
	 * bject, that is normally a java.util.List or a java.util.Map, but can also
	 * be a String or a Number.
	 */
	public static Object propertyListFromStream(InputStream in) {
		return propertyListFromStream(in, null);
	}

	/**
	 * Reads a property list data from InputStream. Returns a property list o
	 * bject, that is normally a java.util.List or a java.util.Map, but can also
	 * be a String or a Number.
	 */
	public static Object propertyListFromStream(InputStream in, PlistDataStructureFactory factory) {
		return new Parser(in, factory).propertyList();
	}

	/**
	 * Saves property list to file.
	 */
	public static void propertyListToFile(File f, Object plist) {
		try {

			try (BufferedWriter out = new BufferedWriter(new FileWriter(f));) {
				writeObject("", out, plist);
			}
		} catch (IOException ioex) {
			throw new CayenneRuntimeException("Error saving plist.", ioex);
		}
	}

	/**
	 * Saves property list to file.
	 */
	public static void propertyListToStream(OutputStream os, Object plist) {
		try {

			try (BufferedWriter out = new BufferedWriter(new OutputStreamWriter(os));) {
				writeObject("", out, plist);
			}
		} catch (IOException ioex) {
			throw new CayenneRuntimeException("Error saving plist.", ioex);
		}
	}

	/**
	 * Internal method to recursively write a property list object.
	 */
	protected static void writeObject(String offset, Writer out, Object plist) throws IOException {
		if (plist == null) {
			return;
		}

		if (plist instanceof Collection) {
			Collection list = (Collection) plist;

			out.write('\n');
			out.write(offset);

			if (list.size() == 0) {
				out.write("()");
				return;
			}

			out.write("(\n");

			String childOffset = offset + "   ";
			Iterator it = list.iterator();
			boolean appended = false;
			while (it.hasNext()) {
				// Java collections can contain nulls, skip them
				Object obj = it.next();
				if (obj != null) {
					if (appended) {
						out.write(", \n");
					}

					out.write(childOffset);
					writeObject(childOffset, out, obj);
					appended = true;
				}
			}

			out.write('\n');
			out.write(offset);
			out.write(')');
		} else if (plist instanceof Map) {
			Map map = (Map) plist;
			out.write('\n');
			out.write(offset);

			if (map.size() == 0) {
				out.write("{}");
				return;
			}

			out.write("{");

			String childOffset = offset + "    ";

			Iterator it = map.entrySet().iterator();
			while (it.hasNext()) {
				// Java collections can contain nulls, skip them
				Map.Entry entry = (Map.Entry) it.next();
				Object key = entry.getKey();
				if (key == null) {
					continue;
				}
				Object obj = entry.getValue();
				if (obj == null) {
					continue;
				}
				out.write('\n');
				out.write(childOffset);
				out.write(quoteString(key.toString()));
				out.write(" = ");
				writeObject(childOffset, out, obj);
				out.write(';');
			}

			out.write('\n');
			out.write(offset);
			out.write('}');
		} else if (plist instanceof String) {
			out.write(quoteString(plist.toString()));
		} else if (plist instanceof Number) {
			out.write(plist.toString());
		} else {
			throw new CayenneRuntimeException("Unsupported class for property list serialization: "
					+ plist.getClass().getName());
		}
	}

	/**
	 * Escapes all doublequotes and backslashes.
	 */
	protected static String escapeString(String str) {
		char[] chars = str.toCharArray();
		int len = chars.length;
		StringBuilder buf = new StringBuilder(len + 3);

		for (int i = 0; i < len; i++) {
			if (chars[i] == '\"' || chars[i] == '\\') {
				buf.append('\\');
			}
			buf.append(chars[i]);
		}

		return buf.toString();
	}

	/**
	 * Returns a quoted String, with all the escapes preprocessed. May return an
	 * unquoted String if it contains no special characters. The rule for a
	 * non-special character is the following:
	 * 
	 * <pre>
	 *       c &gt;= 'a' &amp;&amp; c &lt;= 'z'
	 *       c &gt;= 'A' &amp;&amp; c &lt;= 'Z'
	 *       c &gt;= '0' &amp;&amp; c &lt;= '9'
	 *       c == '_'
	 *       c == '$'
	 *       c == ':'
	 *       c == '.'
	 *       c == '/'
	 * </pre>
	 */
	protected static String quoteString(String str) {
		boolean shouldQuote = false;

		// scan string for special chars,
		// if we have them, string must be quoted

		String noQuoteExtras = "_$:./";
		char[] chars = str.toCharArray();
		int len = chars.length;
		if (len == 0) {
			shouldQuote = true;
		}
		for (int i = 0; !shouldQuote && i < len; i++) {
			char c = chars[i];

			if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')
					|| noQuoteExtras.indexOf(c) >= 0) {
				continue;
			}

			shouldQuote = true;
		}

		str = escapeString(str);
		return (shouldQuote) ? '\"' + str + '\"' : str;
	}

}
