/*
 Copyright © 2018 Hasan Yavuz Özderya

 This file is part of serialplot.

 serialplot 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.

 serialplot 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 serialplot. If not, see <http://www.gnu.org/licenses/>.
*/

#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>
#include <QJsonValue>
#include <QRegularExpression>
#include <algorithm>
#include <functional>

#include "updatechecker.h"

// This link returns the list of downloads in JSON format. Note that we only use
// the first page because results are sorted new to old.
const char BB_DOWNLOADS_URL[] = "https://api.bitbucket.org/2.0/repositories/hyozd/serialplot/downloads?fields=values.name,values.links.self.href";

UpdateChecker::UpdateChecker(QObject *parent) :
 QObject(parent), nam(this)
{
 activeReply = NULL;

 connect(&nam, &QNetworkAccessManager::finished,
 this, &UpdateChecker::onReqFinished);
}

bool UpdateChecker::isChecking() const
{
 return activeReply != NULL && !activeReply->isFinished();
}

void UpdateChecker::checkUpdate()
{
 if (isChecking()) return;

 auto req = QNetworkRequest(QUrl(BB_DOWNLOADS_URL));
 activeReply = nam.get(req);
}

void UpdateChecker::cancelCheck()
{
 if (activeReply != NULL) activeReply->abort();
}

void UpdateChecker::onReqFinished(QNetworkReply* reply)
{
 if (reply->error() != QNetworkReply::NoError)
 {
 emit checkFailed(QString("Network error: ") + reply->errorString());
 }
 else
 {
 QJsonParseError error;
 auto data = QJsonDocument::fromJson(reply->readAll(), &error);
 if (error.error != QJsonParseError::NoError)
 {
 emit checkFailed(QString("JSon parsing error: ") + error.errorString());
 }
 else
 {
 QList<FileInfo> files;
 if (!parseData(data, files))
 {
 // TODO: emit detailed data contents for logging
 emit checkFailed("Data parsing error.");
 }
 else
 {
 FileInfo updateFile;
 if (findUpdate(files, updateFile))
 {
 emit checkFinished(
 true, updateFile.version.toString(), updateFile.link);
 }
 else
 {
 emit checkFinished(false, "", "");
 }
 }
 }
 }
 reply->deleteLater();
 activeReply = NULL;
}

bool UpdateChecker::parseData(const QJsonDocument& data, QList<FileInfo>& files) const
{
 /* Data is expected to be in this form:

 {
 "values": [
 {
 "name": "serialplot-0.9.1-x86_64.AppImage",
 "links": {
 "self": {
 "href": "https://api.bitbucket.org/2.0/repositories/hyOzd/serialplot/downloads/serialplot-0.9.1-x86_64.AppImage"
 }
 }
 }, ... ]
 }
 */

 if (!data.isObject()) return false;

 auto values = data.object()["values"];
 if (values == QJsonValue::Undefined || !values.isArray()) return false;

 for (auto value : values.toArray())
 {
 if (!value.isObject()) return false;

 auto name = value.toObject().value("name");
 if (name.isUndefined() || !name.isString())
 return false;

 auto links = value.toObject().value("links");
 if (links.isUndefined() || !links.isObject())
 return false;

 auto self = links.toObject().value("self");
 if (self.isUndefined() || !self.isObject())
 return false;

 auto href = self.toObject().value("href");
 if (href.isUndefined() || !href.isString())
 return false;

 FileInfo finfo;
 finfo.name = name.toString();
 finfo.link = href.toString();
 finfo.hasVersion = VersionNumber::extract(name.toString(), finfo.version);

 if (finfo.name.contains("amd64") ||
 finfo.name.contains("x86_64") ||
 finfo.name.contains("win64"))
 {
 finfo.arch = FileArch::amd64;
 }
 else if (finfo.name.contains("win32") ||
 finfo.name.contains("i386"))
 {
 finfo.arch = FileArch::_i386;
 }
 else
 {
 finfo.arch = FileArch::unknown;
 }

 files += finfo;
 }

 return true;
}

bool UpdateChecker::findUpdate(const QList<FileInfo>& files, FileInfo& foundFile) const
{
 QList<FileInfo> fflist;

 // filter the file list according to extension and version number
 for (int i = 0; i < files.length(); i++)
 {
 // file type to look
#if defined(Q_OS_WIN)
 const char ext[] = ".exe";
#else // of course linux
 const char ext[] = ".appimage";
#endif

 // file architecture to look
#if defined(Q_PROCESSOR_X86_64)
 const FileArch arch = FileArch::amd64;
#elif defined(Q_PROCESSOR_X86_32)
 const FileArch arch = FileArch::_i386;
#elif defined(Q_PROCESSOR_ARM)
 const FileArch arch = FileArch::arm;
#else
 #error Unknown architecture for update file detection.
#endif

 // filter the file list
 auto file = files[i];
 if (file.name.contains(ext, Qt::CaseInsensitive) &&
 file.arch == arch &&
 file.hasVersion && file.version > CurrentVersion)
 {
 fflist += file;
 }
 }

 // sort and find most up to date file
 if (!fflist.empty())
 {
 std::sort(fflist.begin(), fflist.end(),
 [](const FileInfo& a, const FileInfo& b)
 {
 return a.version > b.version;
 });

 foundFile = fflist[0];
 return true;
 }
 else
 {
 return false;
 }
}