/*
 * Copyright (C) 2014 Emeric Poupon
 *
 * This file is part of LMS.
 *
 * LMS 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.
 *
 * LMS 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 LMS.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "DownloadResource.hpp"

#include <array>
#include <iostream>
#include <iomanip>

#include <Wt/Http/Response.h>
#include <Wt/WLocalDateTime.h>

#include "database/Artist.hpp"
#include "database/Release.hpp"
#include "database/Session.hpp"
#include "database/Track.hpp"
#include "utils/Exception.hpp"
#include "utils/Logger.hpp"
#include "utils/Zipper.hpp"

#include "LmsApplication.hpp"

#define LOG(level)	LMS_LOG(UI, level) << "Download resource: "

namespace UserInterface {

DownloadResource::~DownloadResource()
{
	beingDeleted();
}

void
DownloadResource::handleRequest(const Wt::Http::Request& request, Wt::Http::Response& response)
{
	try
	{
		std::shared_ptr<Zip::Zipper> zipper;

		// First, see if this request is for a continuation
		Wt::Http::ResponseContinuation *continuation = request.continuation();
		if (continuation)
			zipper = Wt::cpp17::any_cast<std::shared_ptr<Zip::Zipper>>(continuation->data());
		else
		{
			zipper = createZipper();
			response.setContentLength(zipper->getTotalZipFile());
			response.setMimeType("application/zip");
		}

		if (!zipper)
			return;

		std::array<std::byte, bufferSize> buffer;
		Zip::SizeType nbWrittenBytes {zipper->writeSome(buffer.data(), buffer.size())};

		response.out().write(reinterpret_cast<const char *>(buffer.data()), nbWrittenBytes);

		if (!zipper->isComplete())
		{
			auto* continuation {response.createContinuation()};
			continuation->setData(zipper);
		}
	}
	catch (Zip::ZipperException& exception)
	{
		LOG(ERROR) << "Zipper exception: " << exception.what();
	}
}


static
std::string
getArtistPathName(Database::Artist::pointer artist)
{
	return StringUtils::replaceInString(artist->getName(), "/", "_");
}

static
std::string
getReleaseArtistPathName(Database::Release::pointer release)
{
	std::string releaseArtistName;

	std::vector<Wt::Dbo::ptr<Database::Artist>> artists;

	artists = release->getReleaseArtists();
	if (artists.empty())
		artists = release->getArtists();

	if (artists.size() > 1)
		releaseArtistName = Wt::WString::tr("Lms.Explore.various-artists").toUTF8();
	else if (artists.size() == 1)
		releaseArtistName = artists.front()->getName();

	releaseArtistName = StringUtils::replaceInString(releaseArtistName, "/", "_");

	return releaseArtistName;
}

static
std::string
getReleasePathName(Database::Release::pointer release)
{
	std::string releaseName;

	if (auto releaseYear {release->getReleaseYear()})
		releaseName += std::to_string(*releaseYear) + " - ";
	releaseName += StringUtils::replaceInString(release->getName(), "/", "_");

	return releaseName;
}

static
std::string
getTrackPathName(Database::Track::pointer track)
{
	std::ostringstream fileName;

	if (auto discNumber {track->getDiscNumber()})
		fileName << *discNumber << ".";
	if (auto trackNumber {track->getTrackNumber()})
		fileName << std::setw(2) << std::setfill('0') << *trackNumber << " - ";

	fileName << StringUtils::replaceInString(track->getName(), "/", "_") << track->getPath().filename().extension().string();

	return fileName.str();
}

static
std::unique_ptr<Zip::Zipper>
createZipper(const std::vector<Database::Track::pointer>& tracks)
{
	std::map<std::string, std::filesystem::path> files;

	for (const Database::Track::pointer& track : tracks)
	{
		std::string releaseName;
		std::string releaseArtistName;
		if (auto release {track->getRelease()})
		{
			releaseName = getReleasePathName(release);
			releaseArtistName = getReleaseArtistPathName(release);
		}

		std::string fileName;
		if (!releaseArtistName.empty())
			fileName += releaseArtistName + "/";
		if (!releaseName.empty())
			fileName += releaseName + "/";
		fileName += getTrackPathName(track);

		files.emplace(fileName, track->getPath());
	}

	return std::make_unique<Zip::Zipper>(files, Wt::WLocalDateTime::currentDateTime().toUTC());
}

DownloadArtistResource::DownloadArtistResource(Database::IdType artistId)
: _artistId {artistId}
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	Database::Artist::pointer artist {Database::Artist::getById(LmsApp->getDbSession(), artistId)};
	if (artist)
		suggestFileName(getArtistPathName(artist) + ".zip");
}

std::unique_ptr<Zip::Zipper>
DownloadArtistResource::createZipper()
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	const Database::Artist::pointer artist {Database::Artist::getById(LmsApp->getDbSession(), _artistId)};
	if (!artist)
	{
		LOG(DEBUG) << "Cannot find artist";
		return {};
	}

	return UserInterface::createZipper(artist->getTracks());
}

DownloadReleaseResource::DownloadReleaseResource(Database::IdType releaseId)
: _releaseId {releaseId}
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	Database::Release::pointer release {Database::Release::getById(LmsApp->getDbSession(), releaseId)};
	if (release)
		suggestFileName(getReleasePathName(release) + ".zip");
}


std::unique_ptr<Zip::Zipper>
DownloadReleaseResource::createZipper()
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	const Database::Release::pointer release {Database::Release::getById(LmsApp->getDbSession(), _releaseId)};
	if (!release)
	{
		LOG(DEBUG) << "Cannot find release";
		return {};
	}

	return UserInterface::createZipper(release->getTracks());
}

DownloadTrackResource::DownloadTrackResource(Database::IdType trackId)
: _trackId {trackId}
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	Database::Track::pointer track {Database::Track::getById(LmsApp->getDbSession(), trackId)};
	if (track)
		suggestFileName(getTrackPathName(track) + ".zip");
}

std::unique_ptr<Zip::Zipper>
DownloadTrackResource::createZipper()
{
	auto transaction {LmsApp->getDbSession().createSharedTransaction()};

	const Database::Track::pointer track {Database::Track::getById(LmsApp->getDbSession(), _trackId)};
	if (!track)
	{
		LOG(DEBUG) << "Cannot find track";
		return {};
	}

	return UserInterface::createZipper({track});
}

} // namespace UserInterface