#include <iostream>

#include <sys/stat.h>
#include <boost/program_options.hpp>

#include <DB/Common/ThreadPool.h>
#include <DB/Core/Types.h>
#include <DB/Client/ConnectionPool.h>
#include <DB/IO/ReadHelpers.h>
#include <DB/IO/ReadBufferFromFileDescriptor.h>
#include <DB/Interpreters/Settings.h>
#include <Poco/AutoPtr.h>
#include <Poco/XML/XMLStream.h>
#include <Poco/SAX/InputSource.h>
#include <Poco/Util/XMLConfiguration.h>
#include <Poco/Exception.h>


/** Tests launcher for ClickHouse.
  * The tool walks through given or default folder in order to find files with
  * tests' description and launches it.
  */
namespace DB
{

namespace ErrorCodes
{
	extern const int POCO_EXCEPTION;
	extern const int STD_EXCEPTION;
	extern const int UNKNOWN_EXCEPTION;
}

class PerformanceTest
{
public:
	PerformanceTest(
		const unsigned   concurrency_,
		const String   & host_,
		const UInt16     port_,
		const String   & default_database_,
		const String   & user_,
		const String   & password_,
		const std::vector<std::string> & input_files,
        const std::vector<std::string> & tags,
        const std::vector<std::string> & without_tags,
        const std::vector<std::string> & names,
        const std::vector<std::string> & without_names,
        const std::vector<std::string> & names_regexp,
        const std::vector<std::string> & without_names_regexp
	):
	   concurrency(concurrency_),
	   connections(concurrency, host_, port_, default_database_, user_, password_),
	   pool(concurrency),
	   testsConfigurations(input_files.size())
	{
		if (input_files.size() < 1) {
			throw Poco::Exception("No tests were specified", 1);
		}

		// std::cerr << std::fixed << std::setprecision(3);
		readTestsConfiguration(input_files);
	}

private:
	unsigned concurrency;
	ConnectionPool connections;
	ThreadPool pool;

	using XMLConfiguration  = Poco::Util::XMLConfiguration;
	using AbstractConfig    = Poco::AutoPtr<Poco::Util::AbstractConfiguration>;
	using Config            = Poco::AutoPtr<XMLConfiguration>;
	using Paths             = std::vector<std::string>;
	using StringToVector    = std::map< std::string, std::vector<std::string> >;
	std::vector<Config> testsConfigurations;

	void readTestsConfiguration(const Paths & input_files)
	{
		testsConfigurations.resize(input_files.size());

		for (size_t i = 0; i != input_files.size(); ++i) {
			const std::string path = input_files[i];
			testsConfigurations[i] = Config(new XMLConfiguration(path));
		}

		// TODO: here will be tests filter on tags, names, regexp matching, etc.
		// { ... }

		// for now let's launch one test only
		if (testsConfigurations.size()) {
			for (auto & testConfig : testsConfigurations) {
				runTest(testConfig);
			}
		}
	}

	void runTest(Config & testConfig)
	{
		std::cout << "Running: " << testConfig->getString("name") << "\n";

		Settings settingsPerTest;
		using Keys = std::vector<std::string>;

		if (testConfig->has("settings")) {
			Keys settings;
			testConfig->keys("settings", settings);

			/// This macro goes through all settings in the Settings.h
			/// and, if found any settings in test's xml configuration
			/// with the same name, sets its value to settingsPerTest
			std::vector<std::string>::iterator it;
			#define EXTRACT_SETTING(TYPE, NAME, DEFAULT) \
				it = std::find(settings.begin(), settings.end(), #NAME); \
				if (it != settings.end()) \
					settingsPerTest.set( \
						#NAME, testConfig->getString("settings."#NAME) \
					);
				APPLY_FOR_SETTINGS(EXTRACT_SETTING)
				APPLY_FOR_LIMITS(EXTRACT_SETTING)
			#undef EXTRACT_SETTING

			if (std::find(settings.begin(), settings.end(), "profile") !=
				settings.end()) {
				// proceed profile settings in a proper way
			}
		}

		std::string query;

		if (testConfig->has("query")) {
			query = testConfig->getString("query");

			if (query.empty()) {
				throw Poco::Exception("The query is empty", 1);
			}
		}

		if (testConfig->has("substitutions")) {
			/// Make "subconfig" of inner xml block
			AbstractConfig substitutionsView(testConfig
											 ->createView("substitutions"));

			StringToVector substitutions;
			constructSubstitutions(substitutionsView, substitutions);

			std::vector<std::string> queries = formatQueries(query, substitutions);
		}
	}

	void constructSubstitutions(AbstractConfig & substitutionsView,
						        StringToVector & substitutions)
	{
		using Keys = std::vector<std::string>;
		Keys xml_substitutions;
		substitutionsView->keys(xml_substitutions);

		for (size_t i = 0; i != xml_substitutions.size(); ++i) {
			const AbstractConfig xml_substitution(
				substitutionsView->createView("substitution[" +
			   								  std::to_string(i) + "]")
			);

			/// Property values for substitution will be stored in a vector
			/// accessible by property name
			std::vector<std::string> xml_values;
			xml_substitution->keys("values", xml_values);

			std::string name = xml_substitution->getString("name");

			for (size_t j = 0; j != xml_values.size(); ++j) {
				substitutions[name].push_back(
					xml_substitution->getString("values.value[" +
											    std::to_string(j) + "]")
				);
			}
		}
	}

	std::vector<std::string> formatQueries(const std::string & query,
					   					   StringToVector substitutions) const
	{
		std::vector<std::string> queries;

		StringToVector::iterator substitutions_first = substitutions.begin();
		StringToVector::iterator substitutions_last  = substitutions.end();
		--substitutions_last;

		runThroughAllOptionsAndPush(
			substitutions_first, substitutions_last, query, queries
		);

		return queries;
	}

	/// Recursive method which goes through all substitution blocks in xml
	/// and replaces property {names} by their values
	void runThroughAllOptionsAndPush(
		StringToVector::iterator substitutions_left,
		StringToVector::iterator substitutions_right,
		const std::string & template_query,
		std::vector<std::string> & queries
	) const
	{
		std::string name = substitutions_left->first;
		std::vector<std::string> values = substitutions_left->second;

		for (auto value = values.begin(); value != values.end(); ++value) {
			/// Copy query string for each unique permutation
			std::string query = template_query;
			size_t substrPos  = 0;

			while (substrPos != std::string::npos) {
				substrPos = query.find("{" + name + "}");

				if (substrPos != std::string::npos) {
					query.replace(
						substrPos, 1 + name.length() + 1,
						*value
					);
				}
			}

			/// If we've reached the end of substitution chain
			if (substitutions_left == substitutions_right) {
				queries.push_back(query);
			} else {
				StringToVector::iterator next_it = substitutions_left;
				++next_it;

				runThroughAllOptionsAndPush(
					next_it, substitutions_right, query, queries
				);
			}
		}
	}
};

}


int mainEntryClickhousePerformanceTest(int argc, char ** argv) {
	using namespace DB;

	try
	{
		using boost::program_options::value;
		using Strings = std::vector<std::string>;

		boost::program_options::options_description desc("Allowed options");
		desc.add_options()
			("help", 																	"produce help message")
			("concurrency,c",		value<unsigned>()->default_value(1),				"number of parallel queries")
			("host,h",				value<std::string>()->default_value("localhost"),	"")
			("port", 				value<UInt16>()->default_value(9000),				"")
			("user", 				value<std::string>()->default_value("default"),		"")
			("password",			value<std::string>()->default_value(""),			"")
			("database",			value<std::string>()->default_value("default"),		"")
			("tag",					value<Strings>(),									"Run only tests with tag")
			("without-tag",			value<Strings>(),									"Do not run tests with tag")
			("name",				value<Strings>(),									"Run tests with specific name")
			("without-name",		value<Strings>(),									"Do not run tests with name")
			("name-regexp",			value<Strings>(),									"Run tests with names matching regexp")
			("without-name-regexp",	value<Strings>(),									"Do not run tests with names matching regexp")
			;

		/// These options will not be displayed in --help
		boost::program_options::options_description hidden("Hidden options");
		hidden.add_options()
			("input-files", value< std::vector<std::string> >(), "")
			;

		/// But they will be legit, though. And they must be given without name
		boost::program_options::positional_options_description positional;
		positional.add("input-files", -1);

		boost::program_options::options_description cmdline_options;
		cmdline_options.add(desc).add(hidden);

		boost::program_options::variables_map options;
		boost::program_options::store(
			boost::program_options::command_line_parser(argc, argv)
									.options(cmdline_options)
									.positional(positional)
									.run(),
			options
		);
		boost::program_options::notify(options);

		if (options.count("help"))
		{
			std::cout << "Usage: " << argv[0] << " [options] [test_file ...] [tests_folder]\n";
			std::cout << desc << "\n";
			return 1;
		}

		if (! options.count("input-files")) {
			std::cerr << "No tests files were specified. See --help" << "\n";
			return 1;
		}

		Strings tests_tags;
		Strings skip_tags;
		Strings tests_names;
		Strings skip_names;
		Strings name_regexp;
		Strings skip_matching_regexp;

		if (options.count("tag")) {
			tests_tags = options["tag"].as<Strings>();
		}

		if (options.count("without-tag")) {
			skip_tags = options["without-tag"].as<Strings>();
		}

		if (options.count("name")) {
			tests_names = options["name"].as<Strings>();
		}

		if (options.count("without-name")) {
			skip_names = options["without-name"].as<Strings>();
		}

		if (options.count("name-regexp")) {
			name_regexp = options["name-regexp"].as<Strings>();
		}

		if (options.count("without-name-regexp")) {
			skip_matching_regexp = options["without-name-regexp"].as<Strings>();
		}

		PerformanceTest performanceTest(
			options["concurrency"].as<unsigned>(),
			options["host"       ].as<std::string>(),
			options["port"       ].as<UInt16>(),
			options["database"   ].as<std::string>(),
			options["user"       ].as<std::string>(),
			options["password"   ].as<std::string>(),
			options["input-files"].as<Strings>(),
			tests_tags,
			skip_tags,
			tests_names,
			skip_names,
			name_regexp,
			skip_matching_regexp
		);
	}
	catch (const Exception & e)
	{
		std::string text = e.displayText();

		std::cerr << "Code: " << e.code() << ". " << text << "\n\n";

		/// Если есть стек-трейс на сервере, то не будем писать стек-трейс на клиенте.
		if (std::string::npos == text.find("Stack trace"))
			std::cerr << "Stack trace:\n"
				<< e.getStackTrace().toString();

		return e.code();
	}
	catch (const Poco::Exception & e)
	{
		std::cerr << "Poco::Exception: " << e.displayText() << "\n";
		return ErrorCodes::POCO_EXCEPTION;
	}
	catch (const std::exception & e)
	{
		std::cerr << "std::exception: " << e.what() << "\n";
		return ErrorCodes::STD_EXCEPTION;
	}
	catch (...)
	{
		std::cerr << "Unknown exception\n";
		return ErrorCodes::UNKNOWN_EXCEPTION;
	}

	return 0;
}