/*
    Copyright (C) 2019-2020 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic 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.

    DCP-o-matic 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 DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "lib/compose.hpp"
#include "lib/cross.h"
#include "lib/dcpomatic_log.h"
#include "lib/digester.h"
#include "lib/disk_writer_messages.h"
#include "lib/exceptions.h"
#include "lib/ext.h"
#include "lib/file_log.h"
#include "lib/nanomsg.h"
#include "lib/version.h"
#include "lib/warnings.h"

#ifdef DCPOMATIC_POSIX
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#endif

#ifdef DCPOMATIC_OSX
#include "lib/stdout_log.h"
#undef nil
extern "C" {
#include <lwext4/file_dev.h>
}
#include <xpc/xpc.h>
#endif

#ifdef DCPOMATIC_LINUX
#include <polkit/polkit.h>
#include <poll.h>
#endif

#ifdef DCPOMATIC_WINDOWS
extern "C" {
#include <lwext4/file_windows.h>
}
#endif

DCPOMATIC_DISABLE_WARNINGS
#include <glibmm.h>
DCPOMATIC_ENABLE_WARNINGS

#include <unistd.h>
#include <sys/types.h>
#include <boost/filesystem.hpp>
#include <boost/algorithm/string.hpp>
#include <iostream>

using std::cin;
using std::min;
using std::string;
using std::runtime_error;
using std::exception;
using std::vector;
using boost::optional;


#define SHORT_TIMEOUT 100
#define LONG_TIMEOUT 2000


#ifdef DCPOMATIC_LINUX
static PolkitAuthority* polkit_authority = 0;
#endif
static Nanomsg* nanomsg = 0;

struct Parameters
{
	boost::filesystem::path dcp_path;
	std::string device;
	std::string posix_partition;
};

#ifdef DCPOMATIC_LINUX
static
void
polkit_callback (GObject *, GAsyncResult* res, gpointer data)
{
	Parameters* parameters = reinterpret_cast<Parameters*> (data);
	PolkitAuthorizationResult* result = polkit_authority_check_authorization_finish (polkit_authority, res, 0);
	if (result && polkit_authorization_result_get_is_authorized(result)) {
		dcpomatic::write (parameters->dcp_path, parameters->device, parameters->posix_partition, nanomsg);
	}
	delete parameters;
	if (result) {
		g_object_unref (result);
	}
}
#endif


bool
idle ()
try
{
	using namespace boost::algorithm;

	optional<string> s = nanomsg->receive (0);
	if (!s) {
		return true;
	}

	LOG_DISK("Writer receives command: %1", *s);

	if (*s == DISK_WRITER_QUIT) {
		exit (EXIT_SUCCESS);
	} else if (*s == DISK_WRITER_PING) {
		nanomsg->send(DISK_WRITER_PONG "\n", LONG_TIMEOUT);
	} else if (*s == DISK_WRITER_UNMOUNT) {
		/* XXX: should do Linux polkit stuff here */
		optional<string> xml_head = nanomsg->receive (LONG_TIMEOUT);
		optional<string> xml_body = nanomsg->receive (LONG_TIMEOUT);
		if (!xml_head || !xml_body) {
			LOG_DISK_NC("Failed to receive unmount request");
			throw CommunicationFailedError ();
		}
		bool const success = Drive(*xml_head + *xml_body).unmount();
		if (!nanomsg->send (success ? (DISK_WRITER_OK "\n") : (DISK_WRITER_ERROR "\n"), LONG_TIMEOUT)) {
			LOG_DISK_NC("CommunicationFailedError in unmount_finished");
			throw CommunicationFailedError ();
		}
	} else if (*s == DISK_WRITER_WRITE) {
		optional<string> dcp_path = nanomsg->receive (LONG_TIMEOUT);
		optional<string> device = nanomsg->receive (LONG_TIMEOUT);
		if (!dcp_path || !device) {
			LOG_DISK_NC("Failed to receive write request");
			throw CommunicationFailedError();
		}

		/* Do some basic sanity checks; this is a bit belt-and-braces but it can't hurt... */

#ifdef DCPOMATIC_OSX
		if (!starts_with(*device, "/dev/disk")) {
			LOG_DISK ("Will not write to %1", *device);
			nanomsg->send(DISK_WRITER_ERROR "\nRefusing to write to this drive\n1\n", LONG_TIMEOUT);
			return true;
		}
#endif
#ifdef DCPOMATIC_LINUX
		if (!starts_with(*device, "/dev/sd") && !starts_with(*device, "/dev/hd")) {
			LOG_DISK ("Will not write to %1", *device);
			nanomsg->send(DISK_WRITER_ERROR "\nRefusing to write to this drive\n1\n", LONG_TIMEOUT);
			return true;
		}
#endif
#ifdef DCPOMATIC_WINDOWS
		if (!starts_with(*device, "\\\\.\\PHYSICALDRIVE")) {
			LOG_DISK ("Will not write to %1", *device);
			nanomsg->send(DISK_WRITER_ERROR "\nRefusing to write to this drive\n1\n", LONG_TIMEOUT);
			return true;
		}
#endif

		bool on_drive_list = false;
		bool mounted = false;
		for (auto const& i: Drive::get()) {
			if (i.device() == *device) {
				on_drive_list = true;
				mounted = i.mounted();
			}
		}

		if (!on_drive_list) {
			LOG_DISK ("Will not write to %1 as it's not recognised as a drive", *device);
			nanomsg->send(DISK_WRITER_ERROR "\nRefusing to write to this drive\n1\n", LONG_TIMEOUT);
			return true;
		}
		if (mounted) {
			LOG_DISK ("Will not write to %1 as it's mounted", *device);
			nanomsg->send(DISK_WRITER_ERROR "\nRefusing to write to this drive\n1\n", LONG_TIMEOUT);
			return true;
		}

		LOG_DISK ("Here we go writing %1 to %2", *dcp_path, *device);

#if defined(DCPOMATIC_LINUX)
		polkit_authority = polkit_authority_get_sync (0, 0);
		PolkitSubject* subject = polkit_unix_process_new_for_owner (getppid(), 0, -1);
		Parameters* parameters = new Parameters;
		parameters->dcp_path = *dcp_path;
		parameters->device = *device;
		parameters->posix_partition = *device;
		/* XXX: don't know if this logic is sensible */
		if (parameters->posix_partition.size() > 0 && isdigit(parameters->posix_partition[parameters->posix_partition.length() - 1])) {
			parameters->posix_partition += "p1";
		} else {
			parameters->posix_partition += "1";
		}
		polkit_authority_check_authorization (
				polkit_authority, subject, "com.dcpomatic.write-drive", 0, POLKIT_CHECK_AUTHORIZATION_FLAGS_ALLOW_USER_INTERACTION, 0, polkit_callback, parameters
				);
#elif defined(DCPOMATIC_OSX)
		string fast_device = boost::algorithm::replace_first_copy (*device, "/dev/disk", "/dev/rdisk");
		dcpomatic::write (*dcp_path, fast_device, fast_device + "s1", nanomsg);
#elif defined(DCPOMATIC_WINDOWS)
		dcpomatic::write (*dcp_path, *device, "", nanomsg);
#endif
	}

	return true;
} catch (exception& e) {
	LOG_DISK("Exception (from idle): %1", e.what());
	return true;
}

int
main ()
{
#ifdef DCPOMATIC_OSX
	/* On macOS this is running as root, so config_path() will be somewhere in root's
	 * home.  Instead, just write to stdout as the macOS process control stuff will
	 * redirect this to a file in /var/log
	 */
	dcpomatic_log.reset(new StdoutLog(LogEntry::TYPE_DISK));
	LOG_DISK("dcpomatic_disk_writer %1 started", dcpomatic_git_commit);
#else
	/* XXX: this is a hack, but I expect we'll need logs and I'm not sure if there's
	 * a better place to put them.
	 */
	dcpomatic_log.reset(new FileLog(config_path() / "disk_writer.log", LogEntry::TYPE_DISK));
	LOG_DISK_NC("dcpomatic_disk_writer started");
#endif

#ifdef DCPOMATIC_OSX
	/* I *think* this consumes the notifyd event that we used to start the process, so we only
	 * get started once per notification.
	 */
        xpc_set_event_stream_handler("com.apple.notifyd.matching", DISPATCH_TARGET_QUEUE_DEFAULT, ^(xpc_object_t) {});
#endif

	try {
		nanomsg = new Nanomsg (false);
	} catch (runtime_error& e) {
		LOG_DISK_NC("Could not set up nanomsg socket");
		exit (EXIT_FAILURE);
	}

	Glib::RefPtr<Glib::MainLoop> ml = Glib::MainLoop::create ();
	Glib::signal_timeout().connect(sigc::ptr_fun(&idle), 500);
	ml->run ();
}