/* Copyright 2015, 2016, Michele Santullo
 * This file is part of "dindexer".
 *
 * "dindexer" 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.
 *
 * "dindexer" 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 "dindexer".  If not, see <http://www.gnu.org/licenses/>.
 */

#include "backend_redis.hpp"
#include "dindexer-machinery/recorddata.hpp"
#include "backends/exposed_functions.hpp"
#include "backends/backend_version.hpp"
#include "dindexerConfig.h"
#include "helpers/stringize.h"
#include <utility>
#include <yaml-cpp/yaml.h>
#include <boost/lexical_cast.hpp>
#include <array>
#include <cstdint>

namespace dindb {
	namespace {
		struct RedisConnectionSettings {
			std::string address;
			uint16_t port;
			uint16_t database;
		};

		std::pair<std::string, mchlib::FileRecordData> pair_list_to_file_record (const redis::Command::hscan_range& parRange, const mchlib::TigerHash& parHash) {
			using boost::lexical_cast;

			mchlib::FileRecordData retval;
			retval.hash = parHash;
			std::array<std::string, 2> mime;
			std::string group_key;

			for (const auto itm : parRange) {
				if (itm.first == "path")
					retval.abs_path = itm.second;
				else if (itm.first == "hash")
					assert(tiger_to_string(parHash) == itm.second);
				else if (itm.first == "size")
					retval.size = lexical_cast<decltype(retval.size)>(
							itm.second);
				else if (itm.first == "level")
					retval.level = lexical_cast<decltype(retval.level)>(
							itm.second);
				else if (itm.first == "mime_type")
					mime[0] = itm.second;
				else if (itm.first == "mime_charset")
					mime[1] = itm.second;
				else if (itm.first == "is_directory")
					retval.is_directory = (itm.second[0] == '0' ? false : true);
				else if (itm.first == "is_symlink")
					retval.is_symlink = (itm.second[0] == '0' ? false : true);
				else if (itm.first == "unreadable")
					retval.unreadable = (itm.second[0] == '0' ? false : true);
				else if (itm.first == "hash_valid")
					retval.hash_valid = (itm.second[0] == '0' ? false : true);
				else if (itm.first == "group_id")
					group_key = itm.second;
			}
			retval.mime_full = mime[0] + mime[1];
			retval.mime_type_offset = 0;
			retval.mime_type_length = retval.mime_charset_offset = static_cast<uint16_t>(mime[0].size());
			retval.mime_charset_length = static_cast<uint16_t>(mime[1].size());
			return std::make_pair(group_key, std::move(retval));
		}

		mchlib::SetRecordDataFull pair_list_to_set_record (const redis::Command::hscan_range& parRange) {
			using boost::lexical_cast;

			mchlib::SetRecordDataFull retval;
			for (const auto& itm : parRange) {
				if (itm.first == "name")
					retval.name = itm.second;
				else if (itm.first == "disk_label")
					retval.disk_label = itm.second;
				else if (itm.first == "fs_uuid")
					retval.fs_uuid = itm.second;
				else if (itm.first == "type")
					retval.type = lexical_cast<char>(itm.second[0]);
				else if (itm.first == "content_type")
					retval.content_type = lexical_cast<char>(itm.second[0]);
			}
			return retval;
		}
	} //unnamed namespace
} //namespace dindb

namespace YAML {
	template<>
	struct convert<dindb::RedisConnectionSettings> {
		static Node encode (const dindb::RedisConnectionSettings& parSettings) {
			Node node;
			node["address"] = parSettings.address;
			node["port"] = parSettings.port;
			node["database"] = parSettings.database;
			return node;
		}

		static bool decode (const Node& parNode, dindb::RedisConnectionSettings& parSettings) {
			if (not parNode.IsMap() or parNode.size() != 2) {
				return false;
			}

			parSettings.address = parNode["address"].as<std::string>();
			parSettings.port = parNode["port"].as<uint16_t>();
			if (parNode["database"])
				parSettings.database = parNode["database"].as<uint16_t>();
			else
				parSettings.database = 0;
			return true;
		}
	};
} //namespace YAML

namespace dindb {
	BackendRedis::BackendRedis(std::string &&parAddress, uint16_t parPort, uint16_t parDatabase, bool parConnect) :
		m_redis(std::move(parAddress), parPort),
		m_database(parDatabase)
	{
		if (parConnect)
			this->connect();
	}

	BackendRedis::~BackendRedis() noexcept {
	}

	void BackendRedis::connect() {
		using boost::lexical_cast;

		m_redis.connect();
		if (m_redis.is_connected() and m_database > 0) {
			m_redis.run("SELECT", lexical_cast<std::string>(m_database));
			m_redis.run("CLIENT", "SETNAME", PROGRAM_NAME "_v" STRINGIZE(VERSION_MAJOR) "." STRINGIZE(VERSION_MINOR) "." STRINGIZE(VERSION_PATCH));
		}
	}

	void BackendRedis::disconnect() {
		m_redis.disconnect();
	}

	void BackendRedis::tag_files (const std::vector<FileIDType>& parFiles, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
	}

	void BackendRedis::tag_files (const std::vector<std::string>& parRegexes, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
	}

	void BackendRedis::delete_tags (const std::vector<FileIDType>& parFiles, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
	}

	void BackendRedis::delete_tags (const std::vector<std::string>& parRegexes, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
	}

	void BackendRedis::delete_all_tags (const std::vector<FileIDType>& parFiles, GroupIDType parSet) {
	}

	void BackendRedis::delete_all_tags (const std::vector<std::string>& parRegexes, GroupIDType parSet) {
	}

	void BackendRedis::delete_group (const std::vector<uint32_t>& parIDs, ConfirmDeleCallback parConf) {
	}

	void BackendRedis::write_files (const std::vector<mchlib::FileRecordData>& parData, const mchlib::SetRecordDataFull& parSetData, const std::string& parSignature) {
		using boost::lexical_cast;
		using boost::string_ref;

		redis::Reply set_id_reply = m_redis.run("HINCRBY", PROGRAM_NAME ":indices", "set", "1");
		const std::string set_key = PROGRAM_NAME ":set:" + lexical_cast<std::string>(redis::get_integer(set_id_reply));
		redis::Reply insert_set_reply = m_redis.run(
			"HMSET",
			set_key,
			"name", parSetData.name,
			"disk_label", parSetData.disk_label,
			"fs_uuid", parSetData.fs_uuid,
			"type", parSetData.type,
			"content_type", parSetData.content_type
		);

		for (const auto& file_data : parData) {
			redis::Reply file_id_reply = m_redis.run("HINCRBY", PROGRAM_NAME ":indices", "files", "1");
			const std::string file_key = PROGRAM_NAME ":file:" + lexical_cast<std::string>(redis::get_integer(file_id_reply));
			const std::string hash = tiger_to_string(file_data.hash);
			redis::Reply insert_file_reply = m_redis.run(
				"HMSET",
				file_key,
				"hash", hash,
				"path", file_data.path(),
				"size", lexical_cast<std::string>(file_data.size),
				"level", lexical_cast<std::string>(file_data.level),
				"mime_type", file_data.mime_type(),
				"mime_charset", file_data.mime_charset(),
				"is_directory", (file_data.is_directory ? '1' : '0'),
				"is_symlink", (file_data.is_symlink ? '1' : '0'),
				"unreadable", (file_data.unreadable ? '1' : '0'),
				"hash_valid", (file_data.hash_valid ? '1' : '0'),
				"group_id", set_key
			);

			redis::Reply insert_hash_reply = m_redis.run(
				"SADD",
				"hash:" + hash,
				file_key
			);
		}
	}

	bool BackendRedis::search_file_by_hash (mchlib::FileRecordData& parItem, mchlib::SetRecordDataFull& parSet, const mchlib::TigerHash& parHash) {
		const std::string hash_key = "hash:" + tiger_to_string(parHash);
		redis::Reply hash_reply = m_redis.run("SRANDMEMBER", hash_key);
		if (redis::RedisVariantType_Integer == hash_reply.which() and not redis::get_integer(hash_reply)) {
			return false;
		}
		else {
			const auto result_id = redis::get_string(hash_reply);
			auto set_key_and_file_item = pair_list_to_file_record(m_redis.hscan(result_id), parHash);
			parItem = std::move(set_key_and_file_item.second);
			const std::string group_key = std::move(set_key_and_file_item.first);

			auto set_item = pair_list_to_set_record(m_redis.hscan(group_key));
			return true;
		}
	}

	std::vector<LocatedItem> BackendRedis::locate_in_db (const std::string& parSearch, const TagList& parTags) {
		return std::vector<LocatedItem>();
	}

	std::vector<LocatedItem> BackendRedis::locate_in_db (const mchlib::TigerHash& parSearch, const TagList& parTags) {
		return std::vector<LocatedItem>();
	}

	std::vector<LocatedSet> BackendRedis::locate_sets_in_db (const std::string& parSearch, bool parCaseInsensitive) {
		return std::vector<LocatedSet>();
	}

	std::vector<LocatedSet> BackendRedis::locate_sets_in_db (const std::string& parSearch, const std::vector<GroupIDType>& parSets, bool parCaseInsensitive) {
		return std::vector<LocatedSet>();
	}

	std::vector<GroupIDType> BackendRedis::find_all_sets() {
		return std::vector<GroupIDType>();
	}

	std::vector<dinhelp::MaxSizedArray<std::string, 4>> BackendRedis::find_set_details (const std::vector<GroupIDType>& parSets) {
		return std::vector<dinhelp::MaxSizedArray<std::string, 4>>();
	}

	std::vector<dinhelp::MaxSizedArray<std::string, 1>> BackendRedis::find_file_details (GroupIDType parSetID, uint16_t parLevel, boost::string_ref parDir) {
		return std::vector<dinhelp::MaxSizedArray<std::string, 1>>();
	}

	std::vector<std::string> BackendRedis::find_paths_starting_by (GroupIDType parGroupID, uint16_t parLevel, boost::string_ref parPath) {
		return std::vector<std::string>();
	}
} //namespace dindb

extern "C" dindb::Backend* dindexer_create_backend (const YAML::Node* parConfig) {
	if (not parConfig)
		return nullptr;

	auto config = parConfig->as<dindb::RedisConnectionSettings>();
	return new dindb::BackendRedis(
		std::move(config.address),
		config.port,
		config.database,
		true
	);
}

extern "C" void dindexer_destroy_backend (dindb::Backend* parDele) {
	if (parDele)
		delete parDele;
}

extern "C" const char* dindexer_backend_name() {
	return "redis";
}

extern "C" int dindexer_backend_iface_version() {
	return dindb::g_current_iface_version;
}