/* Copyright 2020, Michele Santullo
 * This file is part of orotool.
 *
 * Orotool 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.
 *
 * Orotool 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 Orotool.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "app_config.hpp"
#include "orotool_config.hpp"
#include "duckhandy/int_conv.hpp"
#include <fstream>
#include <string>
#include <string_view>
#include <thread>
#include <algorithm>
#include <stdexcept>
#include <iostream>
#include <cctype>
#include <array>

namespace duck {

namespace {
	constexpr const std::size_t g_min_update_timeout = 60;

	constexpr const char g_db_path_sect[] = "system";
	constexpr const char g_db_path[] = "db_path";

	constexpr const char g_worker_threads_sect[] = "system";
	constexpr const char g_worker_threads[] = "worker_threads";

	constexpr const char g_backend_sect[] = "system";
	constexpr const char g_backend[] = "backend";

	constexpr const char g_fetch_extra_delay_sect[] = "options";
	constexpr const char g_fetch_extra_delay[] = "fetch_extra_delay";
	constexpr const char g_fetch_extra_delay_def[] = "30";

	constexpr const char g_api_key_sect[] = "options";
	constexpr const char g_api_key[] = "api_key";
	constexpr const char g_api_key_def[] = "";

	constexpr const char g_store_raw_json_sect[] = "options";
	constexpr const char g_store_raw_json[] = "store_raw_json";
	constexpr const char g_store_raw_json_def[] = "false";

	constexpr const char g_enable_webserver_sect[] = "webserver";
	constexpr const char g_enable_webserver[] = "enabled";
	constexpr const char g_enable_webserver_def[] = "no";

	constexpr const char g_json_store_mode_sect[] = "options";
	constexpr const char g_json_store_mode[] = "json_store_mode";
	constexpr const char g_json_store_mode_def[] = "plain";

	constexpr const char g_items_time_sect[] = "timing";
	constexpr const char g_items_time[] = "items";
	constexpr const char g_items_time_def[] = "604800";

	constexpr const char g_icons_time_sect[] = "timing";
	constexpr const char g_icons_time[] = "icons";
	constexpr const char g_icons_time_def[] = "604800";

	constexpr const char g_shops_time_sect[] = "timing";
	constexpr const char g_shops_time[] = "shops";
	constexpr const char g_shops_time_def[] = "600";

	constexpr const char g_creators_time_sect[] = "timing";
	constexpr const char g_creators_time[] = "creators";
	constexpr const char g_creators_time_def[] = "600";

	constexpr const char g_max_conn_retries_sect[] = "options";
	constexpr const char g_max_conn_retries[] = "max_connection_retries";
	constexpr const char g_max_conn_retries_def[] = "0";

	constexpr const char g_err_retry_timeout_sect[] = "options";
	constexpr const char g_err_retry_timeout[] = "error_retry_timeout";
	constexpr const char g_err_retry_timeout_def[] = "600";

	bool equal (std::string_view a, std::string_view b) {
		return a.size() == b.size() and std::equal(
			a.begin(), a.end(),
			b.begin(),
			[](auto c1, auto c2) {return std::tolower(c1) == std::tolower(c2); }
		);
	}

	bool to_bool (std::string_view a) {
		std::array<std::string_view, 10> yes_list {
			"true", "1", "yes", "on", "ok", "enable", "enabled", "sure", "aye", "one"
		};

		return (
			std::find_if(
				yes_list.begin(),
				yes_list.end(),
				[a](std::string_view b) -> bool { return equal(a, b); }
			) != yes_list.end()
		);
	}

	std::string whole_ini() {
		std::ifstream input(g_config_file_path);
		input >> std::noskipws;
		return { std::istream_iterator<char>(input), std::istream_iterator<char>() };
	}

	std::string_view value_ifp (
		const kamokan::IniFile& ini,
		std::string_view section,
		std::string_view key,
		std::string_view def,
		bool allow_empty
	) {
		const auto& map = ini.parsed();
		auto it_section = map.find(section);
		if (map.end() == it_section)
			return def;

		auto it_setting = it_section->second.find(key);
		if (it_section->second.end() == it_setting)
			return def;

		if (not allow_empty and it_setting->second.empty())
			return def;
		else
			return it_setting->second;
	}

	void print_setting_read_err (
		std::string_view section,
		std::string_view name,
		const std::logic_error& err
	) {
		std::cerr << "Error reading setting [" << section << "] \"" << name
			<< "\": " << err.what() << '\n';
	}
} //unnamed namespace

AppConfig::AppConfig() :
	m_ini(whole_ini())
{
}

AppConfig::~AppConfig() noexcept = default;

std::string_view AppConfig::db_path() const {
	return value_ifp(m_ini, g_db_path_sect, g_db_path, g_def_sqlite_db_name, false);
}

std::string_view AppConfig::api_key() const {
	return value_ifp(m_ini, g_api_key_sect, g_api_key, g_api_key_def, true);
}

std::size_t AppConfig::worker_threads() const {
	std::string_view val = value_ifp(m_ini, g_worker_threads_sect, g_worker_threads, g_def_worker_threads, false);
	if (val == "max") {
		return std::max(3U, std::thread::hardware_concurrency()) - 1;
	}
	else {
		try {
			const std::size_t num = std::stoul(std::string(val.data(), val.size()));
			const std::size_t hard_max = 4U * std::thread::hardware_concurrency();
			return std::max<std::size_t>(2U, std::min(num, hard_max));
		}
		catch (const std::logic_error& err) {
			print_setting_read_err(g_worker_threads_sect, g_worker_threads, err);
			return std::stoul(g_def_worker_threads);
		}
	}
}

std::size_t AppConfig::fetch_extra_delay() const {
	std::string_view val = value_ifp(m_ini, g_fetch_extra_delay_sect, g_fetch_extra_delay, g_fetch_extra_delay_def, false);
	try {
		const std::size_t num = std::stoul(std::string(val.data(), val.size()));
		return std::min<std::size_t>(3600 * 6, num);
	}
	catch (const std::logic_error& err) {
		print_setting_read_err(g_fetch_extra_delay_sect, g_fetch_extra_delay, err);
		return std::stoul(g_fetch_extra_delay_def);
	}
}

std::string_view AppConfig::backend() const {
	return value_ifp(m_ini, g_backend_sect, g_backend, g_def_backend_name, false);
}

bool AppConfig::store_raw_json() const {
	std::string_view val = value_ifp(m_ini, g_store_raw_json_sect, g_store_raw_json, g_store_raw_json_def, false);

	return to_bool(val);
}

bool AppConfig::enable_webserver() const {
	std::string_view val = value_ifp(m_ini, g_enable_webserver_sect, g_enable_webserver, g_enable_webserver_def, false);
	return to_bool(val);
}

std::size_t AppConfig::items_timeout() const {
	std::string_view val = value_ifp(m_ini, g_items_time_sect, g_items_time, g_items_time_def, false);
	return std::max(dhandy::int_conv<std::size_t>(val), g_min_update_timeout);
}

std::size_t AppConfig::icons_timeout() const {
	std::string_view val = value_ifp(m_ini, g_icons_time_sect, g_icons_time, g_icons_time_def, false);
	return std::max(dhandy::int_conv<std::size_t>(val), g_min_update_timeout);
}

std::size_t AppConfig::shops_timeout() const {
	std::string_view val = value_ifp(m_ini, g_shops_time_sect, g_shops_time, g_shops_time_def, false);
	return std::max(dhandy::int_conv<std::size_t>(val), g_min_update_timeout);
}

std::size_t AppConfig::creators_timeout() const {
	std::string_view val = value_ifp(m_ini, g_creators_time_sect, g_creators_time, g_creators_time_def, false);
	return std::max(dhandy::int_conv<std::size_t>(val), g_min_update_timeout);
}

oro::SourceFormat AppConfig::json_store_mode() const {
	std::string_view val = value_ifp(m_ini, g_json_store_mode_sect, g_json_store_mode, g_json_store_mode_def, false);

	if (equal(val, "plain")) {
		return oro::SourceFormat::Plain;
	}
	else if (equal(val, "xz")) {
#if defined(OROTOOL_WITH_LZMA)
		return oro::SourceFormat::Base64_xz;
#else
		throw std::runtime_error(
			std::string("This version of ") + g_project_name +
			" was compiled without lzma support so " + g_json_store_mode +
			" can't be set to xz"
		);
#endif
	}
	else {
		throw std::runtime_error(
			"Invalid value \"" + std::string(val) +
			"\" for option [" + g_json_store_mode_sect + "] " +
			g_json_store_mode
		);
	}
}

std::size_t AppConfig::error_retry_timeout() const {
	std::string_view val = value_ifp(m_ini, g_err_retry_timeout_sect, g_err_retry_timeout, g_err_retry_timeout_def, false);
	return std::max(dhandy::int_conv<std::size_t>(val), g_min_update_timeout);
}

unsigned int AppConfig::max_connection_retries() const {
	std::string_view val = value_ifp(m_ini, g_max_conn_retries_sect, g_max_conn_retries, g_max_conn_retries_def, false);
	return dhandy::int_conv<unsigned int>(val);
}

} //namespace duck