/* XMRig
 * Copyright (c) 2018-2021 SChernykh   <https://github.com/SChernykh>
 * Copyright (c) 2016-2021 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
 *
 *   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, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   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 "base/api/requests/HttpApiRequest.h"
#include "3rdparty/llhttp/llhttp.h"
#include "3rdparty/rapidjson/error/en.h"
#include "base/io/json/Json.h"
#include "base/net/http/HttpData.h"


namespace xmrig {


static const char *kError  = "error";
static const char *kId     = "id";
static const char *kResult = "result";


static inline const char *rpcError(int code) {
    switch (code) {
    case IApiRequest::RPC_PARSE_ERROR:
        return "Parse error";

    case IApiRequest::RPC_INVALID_REQUEST:
        return "Invalid Request";

    case IApiRequest::RPC_METHOD_NOT_FOUND:
        return "Method not found";

    case IApiRequest::RPC_INVALID_PARAMS:
        return "Invalid params";

    default:
        break;
    }

    if (code >= 400 && code < 600) {
        return HttpData::statusName(code);
    }

    return "Internal error";
}


} // namespace xmrig


xmrig::HttpApiRequest::HttpApiRequest(const HttpData &req, bool restricted) :
    ApiRequest(SOURCE_HTTP, restricted),
    m_req(req),
    m_res(req.id()),
    m_url(req.url.c_str())
{
    if (url().size() > 4 && memcmp(url().data(), "/", 1) == 0 && memcmp(url().data()+2, "/", 1) == 0) {
        if (memcmp(url().data(), "/2/", 3) == 0) {
            m_version = 2;
        } else if (memcmp(url().data(), "/1/", 3) == 0) {
            m_version = 1;
        }
        switch (url().size()) {
        case 9:
            if (memcmp(url().data()+3, "config", 6) == 0) {
                m_type = REQ_CONFIG;
            }
            break;
        case 10:
            if (memcmp(url().data()+3, "summary", 7) == 0) {
                m_type = REQ_SUMMARY;
            }
            break;
        case 11:
            if (memcmp(url().data()+3, "backends", 8) == 0) {
                m_type = REQ_BACKENDS;
            }
            break;
        }
    }

    if (url() == "/api.json") {
            m_type = REQ_SUMMARY;
    }

    if (method() == METHOD_POST && url() == "/json_rpc") {
        m_type = REQ_JSON_RPC;
        accept();

        if (hasParseError()) {
            done(RPC_PARSE_ERROR);

            return;
        }

        m_rpcMethod = Json::getString(m_body, "method");
        if (m_rpcMethod.isEmpty()) {
            done(RPC_INVALID_REQUEST);

            return;
        }

        m_state = STATE_NEW;

        return;
    }
}


bool xmrig::HttpApiRequest::accept()
{
    using namespace rapidjson;

    ApiRequest::accept();

    if (m_parsed == 0 && !m_req.body.empty()) {
        m_body.Parse<kParseCommentsFlag | kParseTrailingCommasFlag>(m_req.body.c_str());
        m_parsed = m_body.HasParseError() ? 2 : 1;

        if (!hasParseError()) {
            return true;
        }

        if (type() != REQ_JSON_RPC) {
            reply().AddMember(StringRef(kError), StringRef(GetParseError_En(m_body.GetParseError())), doc().GetAllocator());
        }

        return false;
    }

    return hasParseError();
}


const rapidjson::Value &xmrig::HttpApiRequest::json() const
{
    if (type() == REQ_JSON_RPC) {
        return Json::getValue(m_body, "params");
    }

    return m_body;
}


xmrig::IApiRequest::Method xmrig::HttpApiRequest::method() const
{
    return static_cast<IApiRequest::Method>(m_req.method);
}


void xmrig::HttpApiRequest::done(int status)
{
    ApiRequest::done(status);

    if (type() == REQ_JSON_RPC) {
        using namespace rapidjson;
        auto &allocator = doc().GetAllocator();

        m_res.setStatus(200);

        if (status != 200) {
            setRpcError(status == 404 /* NOT_FOUND */ ? RPC_METHOD_NOT_FOUND : status);
        }
        else if (!reply().HasMember(kResult)) {
            Value result(kObjectType);
            result.AddMember("status", "OK", allocator);

            setRpcResult(result);
        }
    }
    else {
        m_res.setStatus(status);
    }

    m_res.end();
}


void xmrig::HttpApiRequest::setRpcError(int code, const char *message)
{
    using namespace rapidjson;
    auto &allocator = doc().GetAllocator();

    Value error(kObjectType);
    error.AddMember("code",    code, allocator);
    error.AddMember("message", message ? StringRef(message) : StringRef(rpcError(code)), allocator);

    rpcDone(kError, error);
}


void xmrig::HttpApiRequest::setRpcResult(rapidjson::Value &result)
{
    rpcDone(kResult, result);
}


void xmrig::HttpApiRequest::rpcDone(const char *key, rapidjson::Value &value)
{
    ApiRequest::done(0);

    using namespace rapidjson;
    auto &allocator = doc().GetAllocator();

    reply().AddMember(StringRef(key), value, allocator);
    reply().AddMember("jsonrpc", "2.0", allocator);
    reply().AddMember(StringRef(kId), Value().CopyFrom(Json::getValue(m_body, kId), allocator), allocator);

    m_res.setStatus(200);
    m_res.end();
}