/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2015 - ROLI Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found at: www.gnu.org/licenses

   JUCE 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.

   ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.juce.com for more information.

  ==============================================================================
*/

namespace PropertyFileConstants
{
    static const int magicNumber            = (int) ByteOrder::littleEndianInt ("PROP");
    static const int magicNumberCompressed  = (int) ByteOrder::littleEndianInt ("CPRP");

    static const char* const fileTag        = "PROPERTIES";
    static const char* const valueTag       = "VALUE";
    static const char* const nameAttribute  = "name";
    static const char* const valueAttribute = "val";
}

//==============================================================================
PropertiesFile::Options::Options()
    : commonToAllUsers (false),
      ignoreCaseOfKeyNames (false),
      doNotSave (false),
      millisecondsBeforeSaving (3000),
      storageFormat (PropertiesFile::storeAsXML),
      processLock (nullptr)
{
}

File PropertiesFile::Options::getDefaultFile() const
{
    // mustn't have illegal characters in this name..
    jassert (applicationName == File::createLegalFileName (applicationName));

   #if JUCE_MAC || JUCE_IOS
    File dir (commonToAllUsers ?  "/Library/"
                               : "~/Library/");

    if (osxLibrarySubFolder != "Preferences" && ! osxLibrarySubFolder.startsWith ("Application Support"))
    {
        /* The PropertiesFile class always used to put its settings files in "Library/Preferences", but Apple
           have changed their advice, and now stipulate that settings should go in "Library/Application Support".

           Because older apps would be broken by a silent change in this class's behaviour, you must now
           explicitly set the osxLibrarySubFolder value to indicate which path you want to use.

           In newer apps, you should always set this to "Application Support"
           or "Application Support/YourSubFolderName".

           If your app needs to load settings files that were created by older versions of juce and
           you want to maintain backwards-compatibility, then you can set this to "Preferences".
           But.. for better Apple-compliance, the recommended approach would be to write some code that
           finds your old settings files in ~/Library/Preferences, moves them to ~/Library/Application Support,
           and then uses the new path.
        */
        jassertfalse;

        dir = dir.getChildFile ("Application Support");
    }
    else
    {
        dir = dir.getChildFile (osxLibrarySubFolder);
    }

    if (folderName.isNotEmpty())
        dir = dir.getChildFile (folderName);

   #elif JUCE_LINUX || JUCE_ANDROID
    const File dir (File (commonToAllUsers ? "/var" : "~")
                     .getChildFile (folderName.isNotEmpty() ? folderName
                                                            : ("." + applicationName)));

   #elif JUCE_WINDOWS
    File dir (File::getSpecialLocation (commonToAllUsers ? File::commonApplicationDataDirectory
                                                         : File::userApplicationDataDirectory));

    if (dir == File())
        return File();

    dir = dir.getChildFile (folderName.isNotEmpty() ? folderName
                                                    : applicationName);
   #endif

    return dir.getChildFile (applicationName)
              .withFileExtension (filenameSuffix);
}


//==============================================================================
PropertiesFile::PropertiesFile (const File& f, const Options& o)
    : PropertySet (o.ignoreCaseOfKeyNames),
      file (f), options (o),
      loadedOk (false), needsWriting (false)
{
    reload();
}

PropertiesFile::PropertiesFile (const Options& o)
    : PropertySet (o.ignoreCaseOfKeyNames),
      file (o.getDefaultFile()), options (o),
      loadedOk (false), needsWriting (false)
{
    reload();
}

bool PropertiesFile::reload()
{
    ProcessScopedLock pl (createProcessLock());

    if (pl != nullptr && ! pl->isLocked())
        return false; // locking failure..

    loadedOk = (! file.exists()) || loadAsBinary() || loadAsXml();
    return loadedOk;
}

PropertiesFile::~PropertiesFile()
{
    saveIfNeeded();
}

InterProcessLock::ScopedLockType* PropertiesFile::createProcessLock() const
{
    return options.processLock != nullptr ? new InterProcessLock::ScopedLockType (*options.processLock) : nullptr;
}

bool PropertiesFile::saveIfNeeded()
{
    const ScopedLock sl (getLock());
    return (! needsWriting) || save();
}

bool PropertiesFile::needsToBeSaved() const
{
    const ScopedLock sl (getLock());
    return needsWriting;
}

void PropertiesFile::setNeedsToBeSaved (const bool needsToBeSaved_)
{
    const ScopedLock sl (getLock());
    needsWriting = needsToBeSaved_;
}

bool PropertiesFile::save()
{
    const ScopedLock sl (getLock());

    stopTimer();

    if (options.doNotSave
         || file == File()
         || file.isDirectory()
         || ! file.getParentDirectory().createDirectory())
        return false;

    if (options.storageFormat == storeAsXML)
        return saveAsXml();

    return saveAsBinary();
}

bool PropertiesFile::loadAsXml()
{
    XmlDocument parser (file);
    ScopedPointer<XmlElement> doc (parser.getDocumentElement (true));

    if (doc != nullptr && doc->hasTagName (PropertyFileConstants::fileTag))
    {
        doc = parser.getDocumentElement();

        if (doc != nullptr)
        {
            forEachXmlChildElementWithTagName (*doc, e, PropertyFileConstants::valueTag)
            {
                const String name (e->getStringAttribute (PropertyFileConstants::nameAttribute));

                if (name.isNotEmpty())
                {
                    getAllProperties().set (name,
                                            e->getFirstChildElement() != nullptr
                                                ? e->getFirstChildElement()->createDocument ("", true)
                                                : e->getStringAttribute (PropertyFileConstants::valueAttribute));
                }
            }

            return true;
        }

        // must be a pretty broken XML file we're trying to parse here,
        // or a sign that this object needs an InterProcessLock,
        // or just a failure reading the file.  This last reason is why
        // we don't jassertfalse here.
    }

    return false;
}

bool PropertiesFile::saveAsXml()
{
    XmlElement doc (PropertyFileConstants::fileTag);
    const StringPairArray& props = getAllProperties();

    for (int i = 0; i < props.size(); ++i)
    {
        XmlElement* const e = doc.createNewChildElement (PropertyFileConstants::valueTag);
        e->setAttribute (PropertyFileConstants::nameAttribute, props.getAllKeys() [i]);

        // if the value seems to contain xml, store it as such..
        if (XmlElement* const childElement = XmlDocument::parse (props.getAllValues() [i]))
            e->addChildElement (childElement);
        else
            e->setAttribute (PropertyFileConstants::valueAttribute, props.getAllValues() [i]);
    }

    ProcessScopedLock pl (createProcessLock());

    if (pl != nullptr && ! pl->isLocked())
        return false; // locking failure..

    if (doc.writeToFile (file, String()))
    {
        needsWriting = false;
        return true;
    }

    return false;
}

bool PropertiesFile::loadAsBinary()
{
    FileInputStream fileStream (file);

    if (fileStream.openedOk())
    {
        const int magicNumber = fileStream.readInt();

        if (magicNumber == PropertyFileConstants::magicNumberCompressed)
        {
            SubregionStream subStream (&fileStream, 4, -1, false);
            GZIPDecompressorInputStream gzip (subStream);
            return loadAsBinary (gzip);
        }

        if (magicNumber == PropertyFileConstants::magicNumber)
            return loadAsBinary (fileStream);
    }

    return false;
}

bool PropertiesFile::loadAsBinary (InputStream& input)
{
    BufferedInputStream in (input, 2048);

    int numValues = in.readInt();

    while (--numValues >= 0 && ! in.isExhausted())
    {
        const String key (in.readString());
        const String value (in.readString());

        jassert (key.isNotEmpty());
        if (key.isNotEmpty())
            getAllProperties().set (key, value);
    }

    return true;
}

bool PropertiesFile::saveAsBinary()
{
    ProcessScopedLock pl (createProcessLock());

    if (pl != nullptr && ! pl->isLocked())
        return false; // locking failure..

    TemporaryFile tempFile (file);
    ScopedPointer<OutputStream> out (tempFile.getFile().createOutputStream());

    if (out != nullptr)
    {
        if (options.storageFormat == storeAsCompressedBinary)
        {
            out->writeInt (PropertyFileConstants::magicNumberCompressed);
            out->flush();

            out = new GZIPCompressorOutputStream (out.release(), 9, true);
        }
        else
        {
            // have you set up the storage option flags correctly?
            jassert (options.storageFormat == storeAsBinary);

            out->writeInt (PropertyFileConstants::magicNumber);
        }

        const StringPairArray& props = getAllProperties();
        const int numProperties   = props.size();
        const StringArray& keys   = props.getAllKeys();
        const StringArray& values = props.getAllValues();

        out->writeInt (numProperties);

        for (int i = 0; i < numProperties; ++i)
        {
            out->writeString (keys[i]);
            out->writeString (values[i]);
        }

        out = nullptr;

        if (tempFile.overwriteTargetFileWithTemporary())
        {
            needsWriting = false;
            return true;
        }
    }

    return false;
}

void PropertiesFile::timerCallback()
{
    saveIfNeeded();
}

void PropertiesFile::propertyChanged()
{
    sendChangeMessage();

    needsWriting = true;

    if (options.millisecondsBeforeSaving > 0)
        startTimer (options.millisecondsBeforeSaving);
    else if (options.millisecondsBeforeSaving == 0)
        saveIfNeeded();
}
