/*
 * Cantata
 *
 * Copyright (c) 2011-2022 Craig Drummond <craig.p.drummond@gmail.com>
 *
 * ----
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 det.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "mpduser.h"
#include "config.h"
#include "gui/settings.h"
#include "support/globalstatic.h"
#include "support/utils.h"
#include <QCoreApplication>
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QMutexLocker>
#include <QProcess>
#include <QSet>
#include <QTextStream>
#include <signal.h>

const QString MPDUser::constName = QLatin1String("-");

static const QString constDir = QLatin1String("mpd");
static const QString constConfigFile = QLatin1String("mpd.conf");
static const QString constMusicFolderKey = QLatin1String("music_directory");
static const QString constSocketKey = QLatin1String("bind_to_address");
static const QString constPlaylistsKey = QLatin1String("playlist_directory");
static const QString constPidKey = QLatin1String("pid_file");

QString MPDUser::translatedName()
{
	return QObject::tr("Personal");
}

GLOBAL_STATIC(MPDUser, instance)

#if !defined Q_OS_WIN && !defined Q_OS_MAC
static void moveConfig()
{
	QString oldName = QDir::homePath() + "/.config/cantata/" + constDir + "/" + constConfigFile;

	if (QFile::exists(oldName)) {
		QString newName = Utils::dataDir(constDir, true) + constConfigFile;
		if (QFile::exists(newName)) {
			QFile::remove(oldName);
		}
		else {
			QFile::rename(oldName, newName);
		}
	}
}
#endif

MPDUser::MPDUser()
{
#if !defined Q_OS_WIN && !defined Q_OS_MAC
	moveConfig();
#endif
// For now, per-user MPD support is disabled for windows builds
// - as I'm unsure how/if MPD works in windows!!!
// - If enable, also need to fix isRunning!!
#ifndef Q_OS_WIN
	mpdExe = Utils::findExe("mpd");
#endif
	det.name = constName;
	det.allowLocalStreaming = true;
}

bool MPDUser::isSupported()
{
	return !mpdExe.isEmpty();
}

bool MPDUser::isRunning()
{
#ifdef Q_OS_WIN
	return false;
#else
	int pid = getPid();
	return pid ? 0 == ::kill(pid, 0) : false;
#endif
}

static QString readValue(const QString& line)
{
	int start = line.indexOf("\"");
	int end = -1 == start ? -1 : line.indexOf("\"", start + 1);
	return -1 == end ? QString() : line.mid(start + 1, (end - start) - 1);
}

void MPDUser::start()
{
	if (isRunning() || mpdExe.isEmpty()) {
		return;
	}

	init(true);

	if (!det.dir.isEmpty() && !det.hostname.isEmpty()) {
		controlMpd(false);
	}
}

void MPDUser::stop()
{
	if (!isRunning() || mpdExe.isEmpty()) {
		return;
	}

	init(false);
	controlMpd(true);
}

void MPDUser::setMusicFolder(const QString& folder)
{
	if (folder == det.dir) {
		return;
	}
	init(true);

	bool mpdRunning = isRunning();
	if (mpdRunning) {
		controlMpd(true);
	}

	QFile cfgFile(Utils::dataDir(constDir, true) + constConfigFile);
	QStringList lines;
	if (cfgFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
		while (!cfgFile.atEnd()) {
			QString line = QString::fromUtf8(cfgFile.readLine());
			if (line.startsWith(constMusicFolderKey)) {
				lines.append(constMusicFolderKey + " \"" + folder + "\"\n");
			}
			else {
				lines.append(line);
			}
		}
		cfgFile.close();
	}

	if (!lines.isEmpty()) {
		if (cfgFile.open(QIODevice::WriteOnly | QIODevice::Text)) {
			QTextStream out(&cfgFile);
			for (const QString& line : lines) {
				out << line;
			}
			cfgFile.close();
		}
	}
	det.dir = folder;
	det.setDirReadable();
	if (mpdRunning) {
		controlMpd(false);
	}
}

void MPDUser::setDetails(const MPDConnectionDetails& d)
{
	setMusicFolder(d.dir);
	bool dirReadable = det.dirReadable;
	det = d;
	det.dirReadable = dirReadable;
}

static void removeDir(const QString& d)
{
	if (d.isEmpty()) {
		return;
	}
	QDir dir(d);
	if (dir.exists()) {
		QString dirName = dir.dirName();
		if (!dirName.isEmpty()) {
			dir.cdUp();
			dir.rmdir(dirName);
		}
	}
}

void MPDUser::cleanup()
{
	QString cfgFileName(Utils::dataDir(constDir, false) + constConfigFile);
	QFile cfgFile(cfgFileName);
	QSet<QString> files;
	QSet<QString> dirs;
	QString playlistDir;

	if (cfgFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
		QStringList fileKeys = QStringList() << constPidKey << constSocketKey << QLatin1String("db_file")
											 << QLatin1String("state_file") << QLatin1String("sticker_file");
		QStringList dirKeys = QStringList() << constPlaylistsKey;
		while (!cfgFile.atEnd()) {
			QString line = QString::fromUtf8(cfgFile.readLine());
			for (const QString& key : fileKeys) {
				if (line.startsWith(key)) {
					QString file = readValue(line);
					if (!file.isEmpty()) {
						QString dir = Utils::getDir(file);
						if (!dir.isEmpty()) {
							dirs.insert(dir);
						}
						files.insert(file);
						fileKeys.removeAll(key);
					}
				}
			}
			if (playlistDir.isEmpty() && line.startsWith(constPlaylistsKey)) {
				playlistDir = readValue(line);
			}
		}
		files.insert(cfgFileName);
		dirs.insert(Utils::getDir(cfgFileName));
	}

	if (!dirs.isEmpty() && !files.isEmpty()) {
		for (const QString& f : files) {
			QFile::remove(f);
		}

		if (!playlistDir.isEmpty()) {
			QFileInfoList files = QDir(playlistDir).entryInfoList(QStringList() << "*.m3u", QDir::Files | QDir::NoDotAndDotDot);
			for (const QFileInfo& file : files) {
				QFile::remove(file.absoluteFilePath());
			}
			removeDir(playlistDir);
		}

		for (const QString& d : dirs) {
			removeDir(d);
		}
		removeDir(Utils::dataDir(constDir, false));
		removeDir(Utils::cacheDir(constDir, false));
	}
}

void MPDUser::init(bool create)
{
	if (create || det.dir.isEmpty() || det.hostname.isEmpty() || pidFileName.isEmpty()) {
		// Read coverFileName from Cantata settings...
		det.dirReadable = false;

		// Read music folder and socket from MPD conf file...
		QString cfgDir = Utils::dataDir(constDir, create);
		QString cfgName(cfgDir + constConfigFile);
		QString playlists;
		if (create && !QFile::exists(cfgName)) {
			// Conf file does not exist, so we need to create one...
			QFile cfgTemplate(":" + constConfigFile + ".template");

			if (cfgTemplate.open(QIODevice::ReadOnly | QIODevice::Text)) {
				QFile cfgFile(cfgName);
				if (cfgFile.open(QIODevice::WriteOnly | QIODevice::Text)) {
					QString homeDir = QDir::homePath();
					QString cacheDir = Utils::cacheDir(constDir, create);
					QString dataDir = Utils::dataDir(constDir, create);
					QTextStream out(&cfgFile);
					while (!cfgTemplate.atEnd()) {
						QString line = cfgTemplate.readLine();
						line = line.replace(QLatin1String("${HOME}"), homeDir);
						line = line.replace(QLatin1String("${CONFIG_DIR}"), cfgDir);
						line = line.replace(QLatin1String("${DATA_DIR}"), dataDir);
						line = line.replace(QLatin1String("${CACHE_DIR}"), cacheDir);
						line = line.replace("//", "/");
						out << line;

						if (det.dir.isEmpty() && line.startsWith(constMusicFolderKey)) {
							det.dir = Utils::fixPath(readValue(line));
						}
						if (det.hostname.isEmpty() && line.startsWith(constSocketKey)) {
							det.hostname = readValue(line);
						}
						if (pidFileName.isEmpty() && line.startsWith(constPidKey)) {
							pidFileName = readValue(line);
						}
						// Create playlists dir...
						if (playlists.isEmpty() && line.startsWith(constPlaylistsKey)) {
							playlists = readValue(line);
							if (!playlists.isEmpty()) {
								Utils::createWorldReadableDir(playlists, QString());
							}
						}
					}
				}
			}
		}

		if (det.dir.isEmpty() || det.hostname.isEmpty() || pidFileName.isEmpty()) {
			QFile cfgFile(cfgName);
			if (cfgFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
				while (!cfgFile.atEnd() && (det.dir.isEmpty() || det.hostname.isEmpty() || pidFileName.isEmpty())) {
					QString line = QString::fromUtf8(cfgFile.readLine());
					if (det.dir.isEmpty() && line.startsWith(constMusicFolderKey)) {
						det.dir = Utils::fixPath(readValue(line));
					}
					if (det.hostname.isEmpty() && line.startsWith(constSocketKey)) {
						det.hostname = readValue(line);
					}
					if (pidFileName.isEmpty() && line.startsWith(constPidKey)) {
						pidFileName = readValue(line);
					}
				}
			}
			det.setDirReadable();
		}
		det.name = constName;
	}
}

int MPDUser::getPid()
{
	int pid = 0;

	init(false);
	if (!pidFileName.isEmpty()) {
		QFile pidFile(pidFileName);

		if (pidFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
			QTextStream str(&pidFile);
			str >> pid;
		}
	}
	return pid;
}

void MPDUser::killProcess()
{
	int pid = getPid();
	if (pid > 0) {
		::kill(pid, SIGKILL);
	}
}

bool MPDUser::controlMpd(bool stop)
{
	// Both the UI thread (from MainWindow) and MPD thread (from MPDConnection)
	// will stop MPDUser. Use a mutex to ensure thread safety...
	QMutexLocker locker(&mutex);
	QString confFile = Utils::dataDir(constDir, true) + constConfigFile;
	if (!QFile::exists(confFile) || (stop && (pidFileName.isEmpty() || !QFile::exists(pidFileName)))) {
		if (stop) {
			killProcess();
		}

		return false;
	}
	QStringList args = QStringList() << confFile;
	if (stop) {
		args += "--kill";
	}
	else {
		// Ensure cache dir exists before starting MPD
		Utils::cacheDir(constDir, true);
		if (!pidFileName.isEmpty() && QFile::exists(pidFileName)) {
			QFile::remove(pidFileName);
		}
	}
	bool started = QProcess::startDetached(mpdExe, args);
	if (stop) {
		// Wait (up to 2 seconds) for MPD to gracefully terminate
		for (int i = 0; i < 40; ++i) {
			Utils::msleep(50);
			if (!isRunning()) {
				return true;
			}
		}
		// MPD did not terminate, so kill process
		killProcess();
		return !isRunning();
	}
	else if (started) {
		for (int i = 0; i < 8; ++i) {
			Utils::msleep(250);
			if (0 != getPid()) {
				return true;
			}
		}
	}
	return started;
}