/*
 * Strawberry Music Player
 * This file was part of Clementine.
 * Copyright 2010, David Sansome <me@davidsansome.com>
 * Copyright 2012, Martin Björklund <mbj4668@gmail.com>
 * Copyright 2016, Jonas Kvinge <jonas@jkvinge.net>
 *
 * Strawberry 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.
 *
 * Strawberry 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 Strawberry.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */

#include "config.h"

#include <QVariant>
#include <QNetworkReply>
#include <QXmlStreamReader>
#include <QStringList>
#include <QUrlQuery>
#include <QJsonObject>
#include <QJsonDocument>

#include "discogscoverprovider.h"

#include "core/closure.h"
#include "core/logging.h"
#include "core/network.h"
#include "core/utilities.h"

const char *DiscogsCoverProvider::kUrlSearch = "https://api.discogs.com/database/search";
const char *DiscogsCoverProvider::kUrlReleases = "https://api.discogs.com/releases";

const char *DiscogsCoverProvider::kAccessKeyB64 = "dGh6ZnljUGJlZ1NEeXBuSFFxSVk=";
const char *DiscogsCoverProvider::kSecretAccessKeyB64 = "ZkFIcmlaSER4aHhRSlF2U3d0bm5ZVmdxeXFLWUl0UXI=";

DiscogsCoverProvider::DiscogsCoverProvider(QObject *parent) : CoverProvider("Discogs", parent), network_(new NetworkAccessManager(this)) {}

bool DiscogsCoverProvider::StartSearch(const QString &artist, const QString &album, int s_id) {

  //qLog(Debug) << __PRETTY_FUNCTION__ << artist << album << s_id;

  DiscogsCoverSearchContext *s_ctx = new DiscogsCoverSearchContext;
  if (s_ctx == nullptr) return false;
  s_ctx->id = s_id;
  s_ctx->artist = artist;
  s_ctx->album = album;
  s_ctx->r_count = 0;
  requests_search_.insert(s_id, s_ctx);
  SendSearchRequest(s_ctx);

  return true;

}

bool DiscogsCoverProvider::StartRelease(DiscogsCoverSearchContext *s_ctx, int r_id, QString resource_url) {

  //qLog(Debug) << __PRETTY_FUNCTION__ << resource_url;

  DiscogsCoverReleaseContext *r_ctx = new DiscogsCoverReleaseContext;
  if (r_ctx == nullptr) return false;

  s_ctx->r_count++;

  r_ctx->id = r_id;
  r_ctx->resource_url = resource_url;

  r_ctx->s_id = s_ctx->id;

  requests_release_.insert(r_id, r_ctx);
  SendReleaseRequest(s_ctx, r_ctx);

  return true;
  
}

void DiscogsCoverProvider::SendSearchRequest(DiscogsCoverSearchContext *s_ctx) {
    
  //qLog(Debug) << __PRETTY_FUNCTION__;
  
  typedef QPair<QString, QString> Arg;
  typedef QList<Arg> ArgList;

  typedef QPair<QByteArray, QByteArray> EncodedArg;
  typedef QList<EncodedArg> EncodedArgList;

  ArgList args = ArgList()
  << Arg("key", QByteArray::fromBase64(kAccessKeyB64))
  << Arg("secret", QByteArray::fromBase64(kSecretAccessKeyB64));

  args.append(Arg("type", "release"));
  if (!s_ctx->artist.isEmpty()) {
    args.append(Arg("artist", s_ctx->artist.toLower()));
  }
  if (!s_ctx->album.isEmpty()) {
    args.append(Arg("release_title", s_ctx->album.toLower()));
  }

  QUrlQuery url_query;
  QUrl url(kUrlSearch);
  QStringList query_items;

  // Encode the arguments
  for (const Arg &arg : args) {
    EncodedArg encoded_arg(QUrl::toPercentEncoding(arg.first), QUrl::toPercentEncoding(arg.second));
    query_items << QString(encoded_arg.first + "=" + encoded_arg.second);
    url_query.addQueryItem(encoded_arg.first, encoded_arg.second);
  }

  // Sign the request
  const QByteArray data_to_sign = QString("GET\n%1\n%2\n%3").arg(url.host(), url.path(), query_items.join("&")).toLatin1();
  const QByteArray signature(Utilities::HmacSha256(QByteArray::fromBase64(kSecretAccessKeyB64), data_to_sign));

  // Add the signature to the request
  url_query.addQueryItem("Signature", QUrl::toPercentEncoding(signature.toBase64()));

  url.setQuery(url_query);
  QNetworkReply *reply = network_->get(QNetworkRequest(url));

  NewClosure(reply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(SearchRequestError(QNetworkReply::NetworkError, QNetworkReply*, int)), reply, s_ctx->id);
  NewClosure(reply, SIGNAL(finished()), this, SLOT(HandleSearchReply(QNetworkReply*, int)), reply, s_ctx->id);

  return true;

}

void DiscogsCoverProvider::SendReleaseRequest(DiscogsCoverSearchContext *s_ctx, DiscogsCoverReleaseContext *r_ctx) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  typedef QPair<QString, QString> Arg;
  typedef QList<Arg> ArgList;

  typedef QPair<QByteArray, QByteArray> EncodedArg;
  typedef QList<EncodedArg> EncodedArgList;

  QUrlQuery url_query;
  QStringList query_items;

  ArgList args = ArgList()
  << Arg("key", QByteArray::fromBase64(kAccessKeyB64))
  << Arg("secret", QByteArray::fromBase64(kSecretAccessKeyB64));
  // Encode the arguments
  for (const Arg &arg : args) {
    EncodedArg encoded_arg(QUrl::toPercentEncoding(arg.first), QUrl::toPercentEncoding(arg.second));
    query_items << QString(encoded_arg.first + "=" + encoded_arg.second);
    url_query.addQueryItem(encoded_arg.first, encoded_arg.second);
  }

  //QString urlstr = QString("%1/%2").arg(kUrlReleases).arg(r_ctx->id);
  QUrl url(r_ctx->resource_url);
  
  //qLog(Debug) << "Send: " << url;

  // Sign the request
  const QByteArray data_to_sign = QString("GET\n%1\n%2\n%3").arg(url.host(), url.path(), query_items.join("&")).toLatin1();
  const QByteArray signature(Utilities::HmacSha256(QByteArray::fromBase64(kSecretAccessKeyB64), data_to_sign));

  // Add the signature to the request
  url_query.addQueryItem("Signature", QUrl::toPercentEncoding(signature.toBase64()));

  url.setQuery(url_query);
  QNetworkReply *reply = network_->get(QNetworkRequest(url));

  NewClosure(reply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(ReleaseRequestError(QNetworkReply::NetworkError, QNetworkReply*, int, int)), reply, s_ctx->id, r_ctx->id);
  NewClosure(reply, SIGNAL(finished()), this, SLOT(HandleReleaseReply(QNetworkReply*, int, int)), reply, s_ctx->id, r_ctx->id);

  return true;

}

void DiscogsCoverProvider::HandleSearchReply(QNetworkReply *reply, int s_id) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  //QString text(reply->readAll());
  //qLog(Debug) << "text: " << text << "\n";

  reply->deleteLater();

  DiscogsCoverSearchContext *s_ctx;
  if (!requests_search_.contains(s_id)) {
    qLog(Error) << "Discogs: Got reply for cancelled request: " << s_id;
    return;
  }
  s_ctx = requests_search_.value(s_id);
  if (s_ctx == nullptr) return;
  
  QString json_string;
  json_string = reply->readAll();
  QByteArray json_bytes = json_string.toLocal8Bit();
  auto json_doc = QJsonDocument::fromJson(json_bytes);
  if (json_doc.isNull()) {
    qLog(Error) << "Discogs: Failed to create JSON doc.";
    EndSearch(s_ctx);
    return;
  }
  if (!json_doc.isObject()) {
    qLog(Error) << "Discogs: JSON is not an object.";
    EndSearch(s_ctx);
    return;
  }

  QJsonObject json_obj = json_doc.object();
  if (json_obj.isEmpty()) {
    qLog(Error) << "Discogs: JSON object is empty.";
    EndSearch(s_ctx);
    return;
  }

  QVariantMap reply_map = json_obj.toVariantMap();
  if (!reply_map.contains("results")) {
    qLog(Error) << "Discogs: Search reply from server is missing JSON results.";
    //qLog(Error) << "Discogs: Map dump:";
    //qLog(Error) << reply_map;
    EndSearch(s_ctx);
    return;
  }
  
  QVariantList results = reply_map["results"].toList();
  int i = 0;

  for (const QVariant &result : results) {
    QVariantMap result_map = result.toMap();
    int r_id;
    QString title;
    QString resource_url;
    if ((!result_map.contains("id")) || (!result_map.contains("resource_url"))) continue;

    if (result_map.contains("id")) {
      r_id = result_map["id"].toInt();
      //qLog(Debug) << "id: " << r_id;
    }
    if (result_map.contains("title")) {
      title = result_map["title"].toString();
    }
    if (result_map.contains("resource_url")) {
      resource_url = result_map["resource_url"].toString();
      //qLog(Debug) << "resource_url: " << resource_url;
    }
    StartRelease(s_ctx, r_id, resource_url);
    i++;
  }
  if (i <= 0) EndSearch(s_ctx);

}

void DiscogsCoverProvider::HandleReleaseReply(QNetworkReply *reply, int s_id, int r_id) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  //QString text(reply->readAll());
  //qLog(Debug) << "text: " << text << "\n";

  reply->deleteLater();

  DiscogsCoverReleaseContext *r_ctx;
  if (!requests_release_.contains(r_id)) {
    qLog(Error) << "Discogs: Got reply for cancelled request: " << r_id;
    return;
  }
  r_ctx = requests_release_.value(r_id);
  if (r_ctx == nullptr) return;

  DiscogsCoverSearchContext *s_ctx;
  if (!requests_search_.contains(s_id)) {
    qLog(Error) << "Discogs: Got reply for cancelled request: " << s_id << " " << r_id;
    EndSearch(nullptr, r_ctx);
    return;
  }
  s_ctx = requests_search_.value(s_id);
  if (s_ctx == nullptr) return;
  
  QString json_string;
  json_string = reply->readAll();
  QByteArray json_bytes = json_string.toLocal8Bit();
  auto json_doc = QJsonDocument::fromJson(json_bytes);
  if (json_doc.isNull()) {
    qLog(Error) << "Discogs: Failed to create JSON doc.";
    EndSearch(s_ctx, r_ctx);
    return;
  }
  if (!json_doc.isObject()) {
    qLog(Error) << "Discogs: JSON is not an object.";
    EndSearch(s_ctx, r_ctx);
    return;
  }

  QJsonObject json_obj = json_doc.object();
  if (json_obj.isEmpty()) {
    qLog(Error) << "Discogs: JSON object is empty.";
    EndSearch(s_ctx, r_ctx);
    return;
  }

  QVariantMap reply_map = json_obj.toVariantMap();
  if (!reply_map.contains("images")) {
    //qLog(Error) << "Discogs: Search reply from server is missing JSON images.";
    //qLog(Error) << "Discogs: Map dump:";
    //qLog(Error) << reply_map;
    EndSearch(s_ctx, r_ctx);
    return;
  }

  QVariantList results = reply_map["images"].toList();

  for (const QVariant &result : results) {
    QVariantMap result_map = result.toMap();
    CoverSearchResult cover_result;
    cover_result.description = s_ctx->title;
  
    if (result_map.contains("type")) {
      QString type = result_map["type"].toString();
      if (type != "primary") continue;
    }
    if (result_map.contains("height")) {
    }
    if (result_map.contains("width")) {
    }
    if (result_map.contains("resource_url")) {
      cover_result.image_url = QUrl(result_map["resource_url"].toString());
    }
    s_ctx->results.append(cover_result);
  }

  EndSearch(s_ctx, r_ctx);

}

void DiscogsCoverProvider::CancelSearch(int id) {
    
  //qLog(Debug) << __PRETTY_FUNCTION__ << id;

  delete requests_search_.take(id);
}

void DiscogsCoverProvider::SearchRequestError(QNetworkReply::NetworkError error, QNetworkReply *reply, int s_id) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  DiscogsCoverSearchContext *s_ctx;
  if (!requests_search_.contains(s_id)) {
    qLog(Error) << "Discogs: got reply for cancelled request: " << s_id;
    return;
  }
  s_ctx = requests_search_.value(s_id);
  if (s_ctx == nullptr) return;

  EndSearch(s_ctx);

}

void DiscogsCoverProvider::ReleaseRequestError(QNetworkReply::NetworkError error, QNetworkReply *reply, int s_id, int r_id) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  DiscogsCoverSearchContext *s_ctx;
  if (!requests_search_.contains(s_id)) {
    qLog(Error) << "Discogs: got reply for cancelled request: " << s_id << " " << r_id;
    return;
  }
  s_ctx = requests_search_.value(s_id);
  if (s_ctx == nullptr) return;

  DiscogsCoverReleaseContext *r_ctx;
  if (!requests_release_.contains(r_id)) {
    qLog(Error) << "Discogs: got reply for cancelled request: " << s_id << r_id;
    return;
  }
  r_ctx = requests_release_.value(r_id);
  if (r_ctx == nullptr) return;

  EndSearch(s_ctx, r_ctx);

}

void DiscogsCoverProvider::EndSearch(DiscogsCoverSearchContext *s_ctx, DiscogsCoverReleaseContext *r_ctx) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  (void)requests_release_.remove(r_ctx->id);
  delete r_ctx;
  
  if (s_ctx == nullptr) return;
  
  s_ctx->r_count--;
  
  //qLog(Debug) << "r_count: " << s_ctx->r_count;
  
  if (s_ctx->r_count <= 0) EndSearch(s_ctx);

}

void DiscogsCoverProvider::EndSearch(DiscogsCoverSearchContext *s_ctx) {

  //qLog(Debug) << __PRETTY_FUNCTION__;

  (void)requests_search_.remove(s_ctx->id);
  emit SearchFinished(s_ctx->id, s_ctx->results);
  delete s_ctx;

}