/* This file is part of Clementine.
   Copyright 2012, David Sansome <me@davidsansome.com>

   Clementine is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Clementine 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.

   You should have received a copy of the GNU General Public License
   along with Clementine.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "moodbarloader.h"
#include "moodbarpipeline.h"
#include "core/closure.h"
#include "core/utilities.h"

#include <QDir>
#include <QFileInfo>
#include <QNetworkDiskCache>
#include <QTimer>
#include <QThread>
#include <QUrl>

#include <boost/scoped_ptr.hpp>

MoodbarLoader::MoodbarLoader(QObject* parent)
  : QObject(parent),
    cache_(new QNetworkDiskCache(this)),
    kMaxActiveRequests(QThread::idealThreadCount()),
    save_alongside_originals_(false)
{
  cache_->setCacheDirectory(Utilities::GetConfigPath(Utilities::Path_MoodbarCache));
  cache_->setMaximumCacheSize(1024 * 1024); // 1MB - enough for 333 moodbars
}

MoodbarLoader::~MoodbarLoader() {
}

QStringList MoodbarLoader::MoodFilenames(const QString& song_filename) {
  const QFileInfo file_info(song_filename);
  const QString dir_path(file_info.dir().path());

  QStringList parts(file_info.fileName().split('.'));
  parts.removeLast();
  parts.append("mood");
  const QString mood_filename(parts.join("."));

  return QStringList() << dir_path + "/." + mood_filename
                       << dir_path + "/" + mood_filename;
}

MoodbarLoader::Result MoodbarLoader::Load(
        const QUrl& url, QByteArray* data, MoodbarPipeline** async_pipeline) {
  if (url.scheme() != "file") {
    return CannotLoad;
  }
  
  // Are we in the middle of loading this moodbar already?
  if (active_requests_.contains(url)) {
    *async_pipeline = active_requests_[url];
    return WillLoadAsync;
  }
  
  // Check if a mood file exists for this file already
  const QString filename(url.toLocalFile());
  
  foreach (const QString& possible_mood_file, MoodFilenames(filename)) {
    QFile f(possible_mood_file);
    if (f.open(QIODevice::ReadOnly)) {
      qLog(Info) << "Loading moodbar data from" << possible_mood_file;
      *data = f.readAll();
      return Loaded;
    }
  }
  
  // Maybe it exists in the cache?
  boost::scoped_ptr<QIODevice> cache_device(cache_->data(url));
  if (cache_device) {
    qLog(Info) << "Loading cached moodbar data for" << filename;
    *data = cache_device->readAll();
    return Loaded;
  }
  
  // There was no existing file, analyze the audio file and create one.
  MoodbarPipeline* pipeline = new MoodbarPipeline(filename);
  NewClosure(pipeline, SIGNAL(Finished(bool)),
             this, SLOT(RequestFinished(MoodbarPipeline*,QUrl)),
             pipeline, url);

  active_requests_[url] = pipeline;

  if (active_requests_.count() > kMaxActiveRequests) {
    // Just queue this request now, start it later when another request
    // finishes.
    queued_requests_ << url;
  } else if (!StartQueuedRequest(url)) {
    return CannotLoad;
  }

  *async_pipeline = pipeline;
  return WillLoadAsync;
}

bool MoodbarLoader::StartQueuedRequest(const QUrl& url) {
  if (!active_requests_[url]->Start()) {
    delete active_requests_.take(url);
    return false;
  }

  qLog(Info) << "Creating moodbar data for" << url.toLocalFile();

  return true;
}

void MoodbarLoader::RequestFinished(MoodbarPipeline* request, const QUrl& url) {
  if (request->success()) {
    qLog(Info) << "Moodbar data generated successfully for" << url.toLocalFile();
    
    // Save the data in the cache
    QNetworkCacheMetaData metadata;
    metadata.setUrl(url);
    
    QIODevice* cache_file = cache_->prepare(metadata);
    cache_file->write(request->data());
    cache_->insert(cache_file);

    // Save the data alongside the original as well if we're configured to.
    if (save_alongside_originals_) {
      const QString mood_filename(MoodFilenames(url.toLocalFile())[0]);
      QFile mood_file(mood_filename);
      if (mood_file.open(QIODevice::WriteOnly)) {
        mood_file.write(request->data());
      } else {
        qLog(Warning) << "Error opening mood file for writing" << mood_filename;
      }
    }
  }

  qLog(Debug) << "Deleting" << request;

  // Remove the request from the active list and delete it
  active_requests_.take(url);
  QTimer::singleShot(10, request, SLOT(deleteLater()));

  if (!queued_requests_.isEmpty()) {
    StartQueuedRequest(queued_requests_.takeFirst());
  }
}