/*
 * This file is part of the Monero P2Pool <https://github.com/SChernykh/p2pool>
 * Copyright (c) 2021-2023 SChernykh <https://github.com/SChernykh>
 *
 * This program 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, version 3.
 *
 * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "common.h"
#include "merge_mining_client.h"
#include "p2pool.h"
#include "params.h"
#include "json_rpc_request.h"
#include "json_parsers.h"
#include <rapidjson/document.h>

LOG_CATEGORY(MergeMiningClient)

namespace p2pool {

MergeMiningClient::MergeMiningClient(p2pool* pool, const std::string& host)
	: m_host(host)
	, m_port(80)
	, m_pool(pool)
	, m_loop{}
	, m_loopThread{}
	, m_shutdownAsync{}
{
	const size_t k = host.find_last_of(':');
	if (k != std::string::npos) {
		m_host = host.substr(0, k);
		m_port = strtoul(host.substr(k + 1).c_str(), nullptr, 10);
	}

	if (m_host.empty() || (m_port == 0) || (m_port >= 65536)) {
		LOGERR(1, "Invalid host " << host);
		throw std::exception();
	}

	int err = uv_loop_init(&m_loop);
	if (err) {
		LOGERR(1, "failed to create event loop, error " << uv_err_name(err));
		throw std::exception();
	}

	// Init loop user data before running it
	GetLoopUserData(&m_loop);

	err = uv_async_init(&m_loop, &m_shutdownAsync, on_shutdown);
	if (err) {
		LOGERR(1, "uv_async_init failed, error " << uv_err_name(err));
		uv_loop_close(&m_loop);
		throw std::exception();
	}
	m_shutdownAsync.data = this;

	err = uv_thread_create(&m_loopThread, loop, this);
	if (err) {
		LOGERR(1, "failed to start event loop thread, error " << uv_err_name(err));
		uv_loop_close(&m_loop);
		throw std::exception();
	}

	merge_mining_get_chain_id();
}

MergeMiningClient::~MergeMiningClient()
{
	uv_async_send(&m_shutdownAsync);
	uv_thread_join(&m_loopThread);

	LOGINFO(1, "stopped");
}

void MergeMiningClient::merge_mining_get_chain_id()
{
	constexpr char req[] = "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"merge_mining_get_chain_id\"}";

	JSONRPCRequest::call(m_host, m_port, req, std::string(), m_pool->params().m_socks5Proxy,
		[this](const char* data, size_t size, double) {
			parse_merge_mining_get_chain_id(data, size);
		},
		[](const char* data, size_t size, double) {
			if (size > 0) {
				LOGERR(1, "couldn't get merge mining id, error " << log::const_buf(data, size));
			}
		});
}

bool MergeMiningClient::parse_merge_mining_get_chain_id(const char* data, size_t size)
{
	auto err = [this](const char* msg) {
		LOGWARN(1, "merge_mining_get_chain_id RPC call failed: " << msg << ". Trying again in 1 second.");
		std::this_thread::sleep_for(std::chrono::milliseconds(1000));
		merge_mining_get_chain_id();
		return false;
	};

	rapidjson::Document doc;

	if (doc.Parse(data, size).HasParseError() || !doc.IsObject()) {
		return err("parsing failed");
	}

	if (doc.HasMember("error")) {
		return err(doc["error"].IsString() ? doc["error"].GetString() : "an unknown error occurred");
	}

	const auto& result = doc["result"];

	if (!result.IsObject() || !result.HasMember("chain_id")) {
		return err("couldn't parse result");
	}

	const auto& chain_id = result["chain_id"];

	if (!chain_id.IsString() || (chain_id.GetStringLength() != HASH_SIZE * 2)) {
		return err("invalid chain_id");
	}

	const char* s = chain_id.GetString();
	hash id;

	for (uint32_t i = 0; i < HASH_SIZE; ++i) {
		uint8_t d[2];
		if (!from_hex(s[i * 2], d[0]) || !from_hex(s[i * 2 + 1], d[1])) {
			return err("chain_id is not hex-encoded");
		}
		id.h[i] = (d[0] << 4) | d[1];
	}

	m_chainID = id;
	return true;
}

void MergeMiningClient::loop(void* data)
{
	LOGINFO(1, "event loop started");

	MergeMiningClient* client = static_cast<MergeMiningClient*>(data);

	int err = uv_run(&client->m_loop, UV_RUN_DEFAULT);
	if (err) {
		LOGWARN(1, "uv_run returned " << err);
	}

	err = uv_loop_close(&client->m_loop);
	if (err) {
		LOGWARN(1, "uv_loop_close returned error " << uv_err_name(err));
	}

	LOGINFO(1, "event loop stopped");
}

} // namespace p2pool