/*
 * This file is part of the Flowee project
 * Copyright (c) 2009-2010 Satoshi Nakamoto
 * Copyright (c) 2009-2015 The Bitcoin Core developers
 * Copyright (C) 2017,2019 Tom Zander <tom@flowee.org>
 *
 * 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 "chainparamsbase.h"
#include "clientversion.h"
#include "rpcclient.h"
#include <server/util.h>
#include "rpcprotocol.h"
#include <serverutil.h>
#include "utilstrencodings.h"
#include "utiltime.h"

#include <boost/filesystem/operations.hpp>
#include <cstdio>

#include <event2/event.h>
#include <event2/http.h>
#include <event2/buffer.h>
#include <event2/keyvalq_struct.h>

#include <univalue.h>

//////////////////////////////////////////////////////////////////////////////
//
// Start
//

//
// Exception thrown on connection error.  This error is used to determine
// when to wait if -rpcwait is given.
//
class CConnectionFailed : public std::runtime_error
{
public:

    explicit inline CConnectionFailed(const std::string& msg) :
        std::runtime_error(msg)
    {}

};

static bool AppInitRPC(int argc, char* argv[])
{
    //
    // Parameters
    //
    Settings::HubCli allowedArgs;
    try {
        ParseParameters(argc, argv, allowedArgs);
    } catch (const std::exception& e) {
        fprintf(stderr, "Error parsing program options: %s\n", e.what());
        return false;
    }
    if (argc<2 || mapArgs.count("-?") || mapArgs.count("-h") || mapArgs.count("-help") || mapArgs.count("-version")) {
        std::string strUsage = _("Flowee RPC client version") + " " + FormatFullVersion() + "\n";
        if (!mapArgs.count("-version")) {
            strUsage += "\n" + _("Usage:") + "\n" +
                  "  bitcoin-cli [options] <command> [params]  " + _("Send command to the hub") + "\n" +
                  "  bitcoin-cli [options] help                " + _("List commands") + "\n" +
                  "  bitcoin-cli [options] help <command>      " + _("Get help for a command") + "\n";

            strUsage += "\n" + allowedArgs.helpMessage();
        }

        fprintf(stdout, "%s", strUsage.c_str());
        return false;
    }
    if (!boost::filesystem::is_directory(GetDataDir(false))) {
        fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", mapArgs["-datadir"].c_str());
        return false;
    }
    try {
        SelectBaseParams(ChainNameFromCommandLine());
    } catch (const std::exception& e) {
        fprintf(stderr, "Error: %s\n", e.what());
        return false;
    }
    try {
        ReadConfigFile(mapArgs, mapMultiArgs);
    } catch (const std::exception& e) {
        fprintf(stderr,"Error reading configuration file: %s\n", e.what());
        return false;
    }
    return true;
}


/** Reply structure for request_done to fill in */
struct HTTPReply
{
    int status;
    std::string body;
};

static void http_request_done(struct evhttp_request *req, void *ctx)
{
    HTTPReply *reply = static_cast<HTTPReply*>(ctx);

    if (req == NULL) {
        /* If req is NULL, it means an error occurred while connecting, but
         * I'm not sure how to find out which one. We also don't really care.
         */
        reply->status = 0;
        return;
    }

    reply->status = evhttp_request_get_response_code(req);

    struct evbuffer *buf = evhttp_request_get_input_buffer(req);
    if (buf)
    {
        size_t size = evbuffer_get_length(buf);
        const char *data = (const char*)evbuffer_pullup(buf, size);
        if (data)
            reply->body = std::string(data, size);
        evbuffer_drain(buf, size);
    }
}

UniValue CallRPC(const std::string& strMethod, const UniValue& params)
{
    std::string host = GetArg("-rpcconnect", DEFAULT_RPCCONNECT);
    int port = GetArg("-rpcport", BaseParams().RPCPort());

    // Create event base
    struct event_base *base = event_base_new(); // TODO RAII
    if (!base)
        throw std::runtime_error("cannot create event_base");

    // Synchronously look up hostname
    struct evhttp_connection *evcon = evhttp_connection_base_new(base, NULL, host.c_str(), port); // TODO RAII
    if (evcon == NULL)
        throw std::runtime_error("create connection failed");
    evhttp_connection_set_timeout(evcon, GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));

    HTTPReply response;
    struct evhttp_request *req = evhttp_request_new(http_request_done, (void*)&response); // TODO RAII
    if (req == NULL)
        throw std::runtime_error("create http request failed");

    // Get credentials
    std::string strRPCUserColonPass;
    if (mapArgs["-rpcpassword"] == "") {
        // Try fall back to cookie-based authentication if no password is provided
        boost::filesystem::path path = GetAuthCookieFile();
        bool found = GetAuthCookie(path, &strRPCUserColonPass) ;

#ifndef WIN32
        if (!found) // The default place where cookies are stored in our packaging standard
            found = GetAuthCookie("/etc/flowee/.cookie", &strRPCUserColonPass) ;
#endif

        if (!found) {
            throw std::runtime_error(strprintf(
                _("Could not locate RPC credentials. No authentication cookie could be found, and no rpcpassword is set in the configuration file (%s)"),
                    GetConfigFile().string().c_str()));

        }
    } else {
        std::string user = mapArgs["-rpcuser"];
        if (user.empty())
            user = "__cookie__";
        strRPCUserColonPass = user + ":" + mapArgs["-rpcpassword"];
    }

    struct evkeyvalq *output_headers = evhttp_request_get_output_headers(req);
    assert(output_headers);
    evhttp_add_header(output_headers, "Host", host.c_str());
    evhttp_add_header(output_headers, "Connection", "close");
    evhttp_add_header(output_headers, "Authorization", (std::string("Basic ") + EncodeBase64(strRPCUserColonPass)).c_str());

    // Attach request data
    std::string strRequest = JSONRPCRequest(strMethod, params, 1);
    struct evbuffer * output_buffer = evhttp_request_get_output_buffer(req);
    assert(output_buffer);
    evbuffer_add(output_buffer, strRequest.data(), strRequest.size());

    int r = evhttp_make_request(evcon, req, EVHTTP_REQ_POST, "/");
    if (r != 0) {
        evhttp_connection_free(evcon);
        event_base_free(base);
        throw CConnectionFailed("send http request failed");
    }

    event_base_dispatch(base);
    evhttp_connection_free(evcon);
    event_base_free(base);

    if (response.status == 0)
        throw CConnectionFailed("couldn't connect to server");
    else if (response.status == HTTP_UNAUTHORIZED)
        throw std::runtime_error("incorrect rpcuser or rpcpassword (authorization failed)");
    else if (response.status >= 400 && response.status != HTTP_BAD_REQUEST && response.status != HTTP_NOT_FOUND && response.status != HTTP_INTERNAL_SERVER_ERROR)
        throw std::runtime_error(strprintf("server returned HTTP error %d", response.status));
    else if (response.body.empty())
        throw std::runtime_error("no response from server");

    // Parse reply
    UniValue valReply(UniValue::VSTR);
    if (!valReply.read(response.body))
        throw std::runtime_error("couldn't parse reply from server");
    const UniValue& reply = valReply.get_obj();
    if (reply.empty())
        throw std::runtime_error("expected reply to have result, error and id properties");

    return reply;
}

int CommandLineRPC(int argc, char *argv[])
{
    std::string strPrint;
    int nRet = 0;
    try {
        // Skip switches
        while (argc > 1 && IsSwitchChar(argv[1][0])) {
            argc--;
            argv++;
        }

        // Method
        if (argc < 2)
            throw std::runtime_error("too few parameters");
        std::string strMethod = argv[1];

        // Parameters default to strings
        std::vector<std::string> strParams(&argv[2], &argv[argc]);
        UniValue params = RPCConvertValues(strMethod, strParams);

        // Execute and handle connection failures with -rpcwait
        const bool fWait = GetBoolArg("-rpcwait", false);
        do {
            try {
                const UniValue reply = CallRPC(strMethod, params);

                // Parse reply
                const UniValue& result = find_value(reply, "result");
                const UniValue& error  = find_value(reply, "error");

                if (!error.isNull()) {
                    // Error
                    int code = error["code"].get_int();
                    if (fWait && code == RPC_IN_WARMUP)
                        throw CConnectionFailed("server in warmup");
                    strPrint = "error: " + error.write();
                    nRet = abs(code);
                    if (error.isObject())
                    {
                        UniValue errCode = find_value(error, "code");
                        UniValue errMsg  = find_value(error, "message");
                        strPrint = errCode.isNull() ? "" : "error code: "+errCode.getValStr()+"\n";

                        if (errMsg.isStr())
                            strPrint += "error message:\n"+errMsg.get_str();
                    }
                } else {
                    // Result
                    if (result.isNull())
                        strPrint = "";
                    else if (result.isStr())
                        strPrint = result.get_str();
                    else
                        strPrint = result.write(2);
                }
                // Connection succeeded, no need to retry.
                break;
            }
            catch (const CConnectionFailed&) {
                if (fWait)
                    MilliSleep(1000);
                else
                    throw;
            }
        } while (fWait);
    }
    catch (const boost::thread_interrupted&) {
        throw;
    }
    catch (const std::exception& e) {
        strPrint = std::string("error: ") + e.what();
        nRet = EXIT_FAILURE;
    }
    catch (...) {
        PrintExceptionContinue(NULL, "CommandLineRPC()");
        throw;
    }

    if (strPrint != "") {
        fprintf((nRet == 0 ? stdout : stderr), "%s\n", strPrint.c_str());
    }
    return nRet;
}

int main(int argc, char* argv[])
{
    SetupEnvironment();
    if (!SetupNetworking()) {
        fprintf(stderr, "Error: Initializing networking failed\n");
        exit(1);
    }

    try {
        if(!AppInitRPC(argc, argv))
            return EXIT_FAILURE;
    }
    catch (const std::exception& e) {
        PrintExceptionContinue(&e, "AppInitRPC()");
        return EXIT_FAILURE;
    } catch (...) {
        PrintExceptionContinue(NULL, "AppInitRPC()");
        return EXIT_FAILURE;
    }

    int ret = EXIT_FAILURE;
    try {
        ret = CommandLineRPC(argc, argv);
    }
    catch (const std::exception& e) {
        PrintExceptionContinue(&e, "CommandLineRPC()");
    } catch (...) {
        PrintExceptionContinue(NULL, "CommandLineRPC()");
    }
    return ret;
}