//---------------------------------------------------------------------------
//
// SCSI Target Emulator PiSCSI
// for Raspberry Pi
//
// Copyright (C) 2021-2023 Uwe Seimet
//
//---------------------------------------------------------------------------

#include "controllers/controller_manager.h"
#include "shared/protobuf_util.h"
#include "shared/network_util.h"
#include "shared/piscsi_util.h"
#include "shared/piscsi_version.h"
#include "devices/disk.h"
#include "piscsi_response.h"
#include <spdlog/spdlog.h>
#include <filesystem>

using namespace std;
using namespace filesystem;
using namespace piscsi_interface;
using namespace piscsi_util;
using namespace network_util;
using namespace protobuf_util;

void PiscsiResponse::GetDeviceProperties(shared_ptr<Device> device, PbDeviceProperties& properties) const
{
	properties.set_luns(ControllerManager::GetScsiLunMax());
	properties.set_read_only(device->IsReadOnly());
	properties.set_protectable(device->IsProtectable());
	properties.set_stoppable(device->IsStoppable());
	properties.set_removable(device->IsRemovable());
	properties.set_lockable(device->IsLockable());
	properties.set_supports_file(device->SupportsFile());
	properties.set_supports_params(device->SupportsParams());

	if (device->SupportsParams()) {
		for (const auto& [key, value] : device->GetDefaultParams()) {
			auto& map = *properties.mutable_default_params();
			map[key] = value;
		}
	}

	shared_ptr<Disk> disk = dynamic_pointer_cast<Disk>(device);
	if (disk != nullptr && disk->IsSectorSizeConfigurable()) {
		for (const auto& sector_size : disk->GetSupportedSectorSizes()) {
			properties.add_block_sizes(sector_size);
		}
	}
}

void PiscsiResponse::GetDeviceTypeProperties(PbDeviceTypesInfo& device_types_info, PbDeviceType type) const
{
	auto type_properties = device_types_info.add_properties();
	type_properties->set_type(type);
	const auto device = device_factory.CreateDevice(type, 0, "");
	GetDeviceProperties(device, *type_properties->mutable_properties());
}

void PiscsiResponse::GetDeviceTypesInfo(PbDeviceTypesInfo& device_types_info) const
{
	// Start with 2 instead of 1. 1 was the removed SASI drive type.
	int ordinal = 2;
	while (PbDeviceType_IsValid(ordinal)) {
		PbDeviceType type = UNDEFINED;
		PbDeviceType_Parse(PbDeviceType_Name((PbDeviceType)ordinal), &type);
		GetDeviceTypeProperties(device_types_info, type);
		ordinal++;
	}
}

void PiscsiResponse::GetDevice(shared_ptr<Device> device, PbDevice& pb_device, const string& default_folder) const
{
	pb_device.set_id(device->GetId());
	pb_device.set_unit(device->GetLun());
	pb_device.set_vendor(device->GetVendor());
	pb_device.set_product(device->GetProduct());
	pb_device.set_revision(device->GetRevision());
	pb_device.set_type(device->GetType());

    GetDeviceProperties(device, *pb_device.mutable_properties());

    auto status = pb_device.mutable_status();
	status->set_protected_(device->IsProtected());
	status->set_stopped(device->IsStopped());
	status->set_removed(device->IsRemoved());
	status->set_locked(device->IsLocked());

	if (device->SupportsParams()) {
		for (const auto& [key, value] : device->GetParams()) {
			SetParam(pb_device, key, value);
		}
	}

    if (const auto disk = dynamic_pointer_cast<const Disk>(device); disk) {
    	pb_device.set_block_size(device->IsRemoved()? 0 : disk->GetSectorSizeInBytes());
    	pb_device.set_block_count(device->IsRemoved() ? 0: disk->GetBlockCount());
    }

    const auto storage_device = dynamic_pointer_cast<const StorageDevice>(device);
	if (storage_device != nullptr) {
		GetImageFile(*pb_device.mutable_file(), default_folder, device->IsReady() ? storage_device->GetFilename() : "");
	}
}

bool PiscsiResponse::GetImageFile(PbImageFile& image_file, const string& default_folder, const string& filename) const
{
	if (!filename.empty()) {
		image_file.set_name(filename);
		image_file.set_type(device_factory.GetTypeForFile(filename));

		const path p(filename[0] == '/' ? filename : default_folder + "/" + filename);

		image_file.set_read_only(access(p.c_str(), W_OK));

		error_code error;
		if (is_regular_file(p, error) || (is_symlink(p, error) && !is_block_file(p, error))) {
			image_file.set_size(file_size(p));
			return true;
		}
	}

	return false;
}

void PiscsiResponse::GetAvailableImages(PbImageFilesInfo& image_files_info, const string& default_folder,
		const string& folder_pattern, const string& file_pattern, int scan_depth) const
{
	const path default_path(default_folder);
	if (!is_directory(default_path)) {
		return;
	}

	string folder_pattern_lower;
	ranges::transform(folder_pattern, back_inserter(folder_pattern_lower), ::tolower);

	string file_pattern_lower;
	ranges::transform(file_pattern, back_inserter(file_pattern_lower), ::tolower);

	for (auto it = recursive_directory_iterator(default_path, directory_options::follow_directory_symlink);
		it != recursive_directory_iterator(); it++) {
		if (it.depth() > scan_depth) {
			it.disable_recursion_pending();
			continue;
		}

		const string parent = it->path().parent_path().string();

		const string folder = parent.size() > default_folder.size() ? parent.substr(default_folder.size() + 1) : "";

		if (!FilterMatches(folder, folder_pattern_lower) || !FilterMatches(it->path().filename().string(), file_pattern_lower)) {
			continue;
		}

		if (!ValidateImageFile(it->path())) {
			continue;
		}

		const string filename = folder.empty() ?
				it->path().filename().string() : folder + "/" + it->path().filename().string();
		if (PbImageFile image_file; GetImageFile(image_file, default_folder, filename)) {
			GetImageFile(*image_files_info.add_image_files(), default_folder, filename);
		}
	}
}

void PiscsiResponse::GetImageFilesInfo(PbImageFilesInfo& image_files_info, const string& default_folder,
		const string& folder_pattern, const string& file_pattern, int scan_depth) const
{
	image_files_info.set_default_image_folder(default_folder);
	image_files_info.set_depth(scan_depth);

	GetAvailableImages(image_files_info, default_folder, folder_pattern, file_pattern, scan_depth);
}

void PiscsiResponse::GetAvailableImages(PbServerInfo& server_info, const string& default_folder,
		const string& folder_pattern, const string& file_pattern, int scan_depth) const
{
	server_info.mutable_image_files_info()->set_default_image_folder(default_folder);

	GetImageFilesInfo(*server_info.mutable_image_files_info(), default_folder, folder_pattern, file_pattern, scan_depth);
}

void PiscsiResponse::GetReservedIds(PbReservedIdsInfo& reserved_ids_info, const unordered_set<int>& ids) const
{
	for (const int id : ids) {
		reserved_ids_info.add_ids(id);
	}
}

void PiscsiResponse::GetDevices(const unordered_set<shared_ptr<PrimaryDevice>>& devices, PbServerInfo& server_info,
		const string& default_folder) const
{
	for (const auto& device : devices) {
		PbDevice *pb_device = server_info.mutable_devices_info()->add_devices();
		GetDevice(device, *pb_device, default_folder);
	}
}

void PiscsiResponse::GetDevicesInfo(const unordered_set<shared_ptr<PrimaryDevice>>& devices, PbResult& result,
		const PbCommand& command, const string& default_folder) const
{
	set<id_set> id_sets;

	// If no device list was provided in the command get information on all devices
	if (!command.devices_size()) {
		for (const auto& device : devices) {
			id_sets.insert({ device->GetId(), device->GetLun() });
		}
	}
	// Otherwise get information on the devices provided in the command
	else {
		id_sets = MatchDevices(devices, result, command);
		if (id_sets.empty()) {
			return;
		}
	}

	auto devices_info = result.mutable_devices_info();
	for (const auto& [id, lun] : id_sets) {
		for (const auto& d : devices) {
			if (d->GetId() == id && d->GetLun() == lun) {
				GetDevice(d, *devices_info->add_devices(), default_folder);
				break;
			}
		}
	}

	result.set_status(true);
}

void PiscsiResponse::GetServerInfo(PbServerInfo& server_info, const PbCommand& command,
		const unordered_set<shared_ptr<PrimaryDevice>>& devices, const unordered_set<int>& reserved_ids,
		const string& default_folder, int scan_depth) const
{
	const vector<string> command_operations = Split(GetParam(command, "operations"), ',');
	set<string, less<>> operations;
	for (const string& operation : command_operations) {
		string op;
		ranges::transform(operation, back_inserter(op), ::toupper);
		operations.insert(op);
	}

	if (!operations.empty()) {
		spdlog::trace("Requested operation(s): " + Join(operations, ","));
	}

	if (HasOperation(operations, PbOperation::VERSION_INFO)) {
		GetVersionInfo(*server_info.mutable_version_info());
	}

	if (HasOperation(operations, PbOperation::LOG_LEVEL_INFO)) {
		GetLogLevelInfo(*server_info.mutable_log_level_info());
	}

	if (HasOperation(operations, PbOperation::DEVICE_TYPES_INFO)) {
		GetDeviceTypesInfo(*server_info.mutable_device_types_info());
	}

	if (HasOperation(operations, PbOperation::DEFAULT_IMAGE_FILES_INFO)) {
		GetAvailableImages(server_info, default_folder, GetParam(command, "folder_pattern"),
				GetParam(command, "file_pattern"), scan_depth);
	}

	if (HasOperation(operations, PbOperation::NETWORK_INTERFACES_INFO)) {
		GetNetworkInterfacesInfo(*server_info.mutable_network_interfaces_info());
	}

	if (HasOperation(operations, PbOperation::MAPPING_INFO)) {
		GetMappingInfo(*server_info.mutable_mapping_info());
	}

	if (HasOperation(operations, PbOperation::STATISTICS_INFO)) {
		GetStatisticsInfo(*server_info.mutable_statistics_info(), devices);
	}

	if (HasOperation(operations, PbOperation::DEVICES_INFO)) {
		GetDevices(devices, server_info, default_folder);
	}

	if (HasOperation(operations, PbOperation::RESERVED_IDS_INFO)) {
		GetReservedIds(*server_info.mutable_reserved_ids_info(), reserved_ids);
	}

	if (HasOperation(operations, PbOperation::OPERATION_INFO)) {
		GetOperationInfo(*server_info.mutable_operation_info(), scan_depth);
	}
}

void PiscsiResponse::GetVersionInfo(PbVersionInfo& version_info) const
{
	version_info.set_major_version(piscsi_major_version);
	version_info.set_minor_version(piscsi_minor_version);
	version_info.set_patch_version(piscsi_patch_version);
}

void PiscsiResponse::GetLogLevelInfo(PbLogLevelInfo& log_level_info) const
{
	for (const auto& log_level : spdlog::level::level_string_views) {
		log_level_info.add_log_levels(log_level.data());
	}

	log_level_info.set_current_log_level(spdlog::level::level_string_views[spdlog::get_level()].data());
}

void PiscsiResponse::GetNetworkInterfacesInfo(PbNetworkInterfacesInfo& network_interfaces_info) const
{
	for (const auto& network_interface : GetNetworkInterfaces()) {
		network_interfaces_info.add_name(network_interface);
	}
}

void PiscsiResponse::GetMappingInfo(PbMappingInfo& mapping_info) const
{
	for (const auto& [name, type] : device_factory.GetExtensionMapping()) {
		(*mapping_info.mutable_mapping())[name] = type;
	}
}

void PiscsiResponse::GetStatisticsInfo(PbStatisticsInfo& statistics_info,
		const unordered_set<shared_ptr<PrimaryDevice>>& devices) const
{
	for (const auto& device : devices) {
		for (const auto& statistics : device->GetStatistics()) {
			auto s = statistics_info.add_statistics();
			s->set_id(statistics.id());
			s->set_unit(statistics.unit());
			s->set_category(statistics.category());
			s->set_key(statistics.key());
			s->set_value(statistics.value());
		}
	}
}

void PiscsiResponse::GetOperationInfo(PbOperationInfo& operation_info, int depth) const
{
	auto operation = CreateOperation(operation_info, ATTACH, "Attach device, device-specific parameters are required");
	AddOperationParameter(*operation, "name", "Image file name in case of a mass storage device");
	AddOperationParameter(*operation, "interface", "Comma-separated prioritized network interface list");
	AddOperationParameter(*operation, "inet", "IP address and netmask of the network bridge");
	AddOperationParameter(*operation, "cmd", "Print command for the printer device");

	CreateOperation(operation_info, DETACH, "Detach device, device-specific parameters are required");

	CreateOperation(operation_info, DETACH_ALL, "Detach all devices");

	CreateOperation(operation_info, START, "Start device, device-specific parameters are required");

	CreateOperation(operation_info, STOP, "Stop device, device-specific parameters are required");

	operation = CreateOperation(operation_info, INSERT, "Insert medium, device-specific parameters are required");
	AddOperationParameter(*operation, "file", "Image file name", "", true);

	CreateOperation(operation_info, EJECT, "Eject medium, device-specific parameters are required");

	CreateOperation(operation_info, PROTECT, "Protect medium, device-specific parameters are required");

	CreateOperation(operation_info, UNPROTECT, "Unprotect medium, device-specific parameters are required");

	operation = CreateOperation(operation_info, SERVER_INFO, "Get piscsi server information");
	if (depth) {
		AddOperationParameter(*operation, "folder_pattern", "Pattern for filtering image folder names");
	}
	AddOperationParameter(*operation, "file_pattern", "Pattern for filtering image file names");

	CreateOperation(operation_info, VERSION_INFO, "Get piscsi server version");

	CreateOperation(operation_info, DEVICES_INFO, "Get information on attached devices");

	CreateOperation(operation_info, DEVICE_TYPES_INFO, "Get device properties by device type");

	operation = CreateOperation(operation_info, DEFAULT_IMAGE_FILES_INFO, "Get information on available image files");
	if (depth) {
		AddOperationParameter(*operation, "folder_pattern", "Pattern for filtering image folder names");
	}
	AddOperationParameter(*operation, "file_pattern", "Pattern for filtering image file names");

	operation = CreateOperation(operation_info, IMAGE_FILE_INFO, "Get information on image file");
	AddOperationParameter(*operation, "file", "Image file name", "", true);

	CreateOperation(operation_info, LOG_LEVEL_INFO, "Get log level information");

	CreateOperation(operation_info, NETWORK_INTERFACES_INFO, "Get the available network interfaces");

	CreateOperation(operation_info, MAPPING_INFO, "Get mapping of extensions to device types");

	CreateOperation(operation_info, STATISTICS_INFO, "Get statistics");

	CreateOperation(operation_info, RESERVED_IDS_INFO, "Get list of reserved device IDs");

	operation = CreateOperation(operation_info, DEFAULT_FOLDER, "Set default image file folder");
	AddOperationParameter(*operation, "folder", "Default image file folder name", "", true);

	operation = CreateOperation(operation_info, LOG_LEVEL, "Set log level");
	AddOperationParameter(*operation, "level", "New log level", "", true);

	operation = CreateOperation(operation_info, RESERVE_IDS, "Reserve device IDs");
	AddOperationParameter(*operation, "ids", "Comma-separated device ID list", "", true);

	operation = CreateOperation(operation_info, SHUT_DOWN, "Shut down or reboot");
	if (getuid()) {
		AddOperationParameter(*operation, "mode", "Shutdown mode", "", true, { "rascsi" } );
	}
	else {
		// System shutdown/reboot requires root permissions
		AddOperationParameter(*operation, "mode", "Shutdown mode", "", true, { "rascsi", "system", "reboot" } );
	}

	operation = CreateOperation(operation_info, CREATE_IMAGE, "Create an image file");
	AddOperationParameter(*operation, "file", "Image file name", "", true);
	AddOperationParameter(*operation, "size", "Image file size in bytes", "", true);
	AddOperationParameter(*operation, "read_only",  "Read-only flag", "false", false, { "true", "false" } );

	operation = CreateOperation(operation_info, DELETE_IMAGE, "Delete image file");
	AddOperationParameter(*operation, "file", "Image file name", "", true);

	operation = CreateOperation(operation_info, RENAME_IMAGE, "Rename image file");
	AddOperationParameter(*operation, "from", "Source image file name", "", true);
	AddOperationParameter(*operation, "to", "Destination image file name", "", true);

	operation = CreateOperation(operation_info, COPY_IMAGE, "Copy image file");
	AddOperationParameter(*operation, "from", "Source image file name", "", true);
	AddOperationParameter(*operation, "to", "Destination image file name", "", true);
	AddOperationParameter(*operation, "read_only", "Read-only flag", "false", false, { "true", "false" } );

	operation = CreateOperation(operation_info, PROTECT_IMAGE, "Write-protect image file");
	AddOperationParameter(*operation, "file", "Image file name", "", true);

	operation = CreateOperation(operation_info, UNPROTECT_IMAGE, "Make image file writable");
	AddOperationParameter(*operation, "file", "Image file name", "", true);

	operation = CreateOperation(operation_info, CHECK_AUTHENTICATION, "Check whether an authentication token is valid");
	AddOperationParameter(*operation, "token", "Authentication token to be checked", "", true);

	CreateOperation(operation_info, OPERATION_INFO, "Get operation meta data");
}

// This method returns a raw pointer because protobuf does not have support for smart pointers
PbOperationMetaData *PiscsiResponse::CreateOperation(PbOperationInfo& operation_info, const PbOperation& operation,
		const string& description) const
{
	PbOperationMetaData meta_data;
	meta_data.set_server_side_name(PbOperation_Name(operation));
	meta_data.set_description(description);
	int ordinal = PbOperation_descriptor()->FindValueByName(PbOperation_Name(operation))->index();
	(*operation_info.mutable_operations())[ordinal] = meta_data;
	return &(*operation_info.mutable_operations())[ordinal];
}

void PiscsiResponse::AddOperationParameter(PbOperationMetaData& meta_data, const string& name,
		const string& description, const string& default_value, bool is_mandatory,
		const vector<string>& permitted_values) const
{
	auto parameter = meta_data.add_parameters();
	parameter->set_name(name);
	parameter->set_description(description);
	parameter->set_default_value(default_value);
	parameter->set_is_mandatory(is_mandatory);
	for (const auto& permitted_value : permitted_values) {
		parameter->add_permitted_values(permitted_value);
	}
}

set<id_set> PiscsiResponse::MatchDevices(const unordered_set<shared_ptr<PrimaryDevice>>& devices, PbResult& result,
		const PbCommand& command) const
{
	set<id_set> id_sets;

	for (const auto& device : command.devices()) {
		bool has_device = false;
		for (const auto& d : devices) {
			if (d->GetId() == device.id() && d->GetLun() == device.unit()) {
				id_sets.insert({ device.id(), device.unit() });
				has_device = true;
				break;
			}
		}

		if (!has_device) {
			id_sets.clear();

			result.set_status(false);
			result.set_msg("No device for " + to_string(device.id()) + ":" + to_string(device.unit()));

			break;
		}
	}

	return id_sets;
}

bool PiscsiResponse::ValidateImageFile(const path& path)
{
	if (path.filename().string().starts_with(".")) {
		return false;
	}

	filesystem::path p(path);

	// Follow symlink
	if (is_symlink(p)) {
		p = read_symlink(p);
		if (!exists(p)) {
			spdlog::warn("Image file symlink '" + path.string() + "' is broken");
			return false;
		}
	}

	if (is_directory(p) || (is_other(p) && !is_block_file(p))) {
		return false;
	}

	if (!is_block_file(p) && file_size(p) < 256) {
		spdlog::warn("Image file '" + p.string() + "' is invalid");
		return false;
	}

	return true;
}

bool PiscsiResponse::FilterMatches(const string& input, string_view pattern_lower)
{
	if (!pattern_lower.empty()) {
		string name_lower;
		ranges::transform(input, back_inserter(name_lower), ::tolower);

		if (name_lower.find(pattern_lower) == string::npos) {
			return false;
		}
	}

	return true;
}

bool PiscsiResponse::HasOperation(const set<string, less<>>& operations, PbOperation operation)
{
	return operations.empty() || operations.contains(PbOperation_Name(operation));
}