// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin Core developers
// Copyright (c) 2016-2023 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php .

#include "chainparamsbase.h"
#include "clientversion.h"
#include "fs.h"
#include "rpc/client.h"
#include "rpc/protocol.h"
#include "util/match.h"
#include "util/system.h"
#include "util/strencodings.h"

#include <stdio.h>

#include <event2/buffer.h>
#include <event2/keyvalq_struct.h>
#include "support/events.h"

#include <univalue.h>

#ifdef WIN32
#include <windows.h>
#else
#include <termios.h>
#include <unistd.h>
#include <cerrno>
#endif

const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;

static const char DEFAULT_RPCCONNECT[] = "127.0.0.1";
static const int DEFAULT_HTTP_CLIENT_TIMEOUT=900;
static const int CONTINUE_EXECUTION=-1;

std::string HelpMessageCli()
{
    std::string strUsage;
    strUsage += HelpMessageGroup(_("Options:"));
    strUsage += HelpMessageOpt("-?", _("This help message"));
    strUsage += HelpMessageOpt("-conf=<file>", strprintf(_("Specify configuration file. Relative paths will be prefixed by datadir location. (default: %s)"), BITCOIN_CONF_FILENAME));
    strUsage += HelpMessageOpt("-datadir=<dir>", _("Specify data directory (this path cannot use '~')"));
    strUsage += HelpMessageOpt("-stdin", _("Read extra arguments from standard input, one per line until EOF/Ctrl-D (recommended for sensitive information such as passphrases). If first extra argument is `walletpassphrase` then the first line(password) will not be echoed."));
    AppendParamsHelpMessages(strUsage);
    strUsage += HelpMessageOpt("-rpcconnect=<ip>", strprintf(_("Send commands to node running on <ip> (default: %s)"), DEFAULT_RPCCONNECT));
    strUsage += HelpMessageOpt("-rpcport=<port>", strprintf(_("Connect to JSON-RPC on <port> (default: %u or testnet: %u)"), 8232, 18232));
    strUsage += HelpMessageOpt("-rpcwait", _("Wait for RPC server to start"));
    strUsage += HelpMessageOpt("-rpcuser=<user>", _("Username for JSON-RPC connections"));
    strUsage += HelpMessageOpt("-rpcpassword=<pw>", _("Password for JSON-RPC connections"));
    strUsage += HelpMessageOpt("-rpcclienttimeout=<n>", strprintf(_("Timeout in seconds during HTTP requests, or 0 for no timeout. (default: %d)"), DEFAULT_HTTP_CLIENT_TIMEOUT));

    return strUsage;
}

//////////////////////////////////////////////////////////////////////////////
//
// 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)
    {}

};

//
// This function returns either one of EXIT_ codes when it's expected to stop the process or
// CONTINUE_EXECUTION when it's expected to continue further.
//
static int AppInitRPC(int argc, char* argv[])
{
    static_assert(CONTINUE_EXECUTION != EXIT_FAILURE,
                  "CONTINUE_EXECUTION should be different from EXIT_FAILURE");
    static_assert(CONTINUE_EXECUTION != EXIT_SUCCESS,
                  "CONTINUE_EXECUTION should be different from EXIT_SUCCESS");
    //
    // Parameters
    //
    ParseParameters(argc, argv);
    if (argc<2 || mapArgs.count("-?") || mapArgs.count("-h") || mapArgs.count("-help") || mapArgs.count("-version")) {
        std::string strUsage = _("Zcash RPC client version") + " " + FormatFullVersion() + "\n" + PrivacyInfo();
        if (!mapArgs.count("-version")) {
            strUsage += "\n" + _("Usage:") + "\n" +
                  "  zcash-cli [options] <command> [params]  " + _("Send command to Zcash") + "\n" +
                  "  zcash-cli [options] help                " + _("List commands") + "\n" +
                  "  zcash-cli [options] help <command>      " + _("Get help for a command") + "\n";

            strUsage += "\n" + HelpMessageCli();
        } else {
            strUsage += LicenseInfo();
        }

        fprintf(stdout, "%s", strUsage.c_str());
        if (argc < 2) {
            fprintf(stderr, "Error: too few parameters\n");
            return EXIT_FAILURE;
        }
        return EXIT_SUCCESS;
    }
    if (!fs::is_directory(GetDataDir(false))) {
        fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", mapArgs["-datadir"].c_str());
        return EXIT_FAILURE;
    }
    try {
        ReadConfigFile(GetArg("-conf", BITCOIN_CONF_FILENAME), mapArgs, mapMultiArgs);
    } catch (const std::exception& e) {
        fprintf(stderr,"Error reading configuration file: %s\n", e.what());
        return EXIT_FAILURE;
    }
    // Check for -testnet or -regtest parameter (BaseParams() calls are only valid after this clause)
    try {
        SelectBaseParams(ChainNameFromCommandLine());
    } catch(std::exception &e) {
        fprintf(stderr, "Error: %s\n", e.what());
        return EXIT_FAILURE;
    }
    if (GetBoolArg("-rpcssl", false))
    {
        fprintf(stderr, "Error: SSL mode for RPC (-rpcssl) is no longer supported.\n");
        return EXIT_FAILURE;
    }
    return CONTINUE_EXECUTION;
}


/** Reply structure for request_done to fill in */
struct HTTPReply
{
    HTTPReply(): status(0), error(-1) {}

    int status;
    int error;
    std::string body;
};

const char *http_errorstring(int code)
{
    switch(code) {
#if LIBEVENT_VERSION_NUMBER >= 0x02010300
    case EVREQ_HTTP_TIMEOUT:
        return "timeout reached";
    case EVREQ_HTTP_EOF:
        return "EOF reached";
    case EVREQ_HTTP_INVALID_HEADER:
        return "error while reading header, or invalid header";
    case EVREQ_HTTP_BUFFER_ERROR:
        return "error encountered while reading or writing";
    case EVREQ_HTTP_REQUEST_CANCEL:
        return "request was canceled";
    case EVREQ_HTTP_DATA_TOO_LONG:
        return "response body is larger than allowed";
#endif
    default:
        return "unknown";
    }
}

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: the
         * error code will have been passed to http_error_cb.
         */
        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);
    }
}

#if LIBEVENT_VERSION_NUMBER >= 0x02010300
static void http_error_cb(enum evhttp_request_error err, void *ctx)
{
    HTTPReply *reply = static_cast<HTTPReply*>(ctx);
    reply->error = err;
}
#endif

tl::expected<UniValue, UniValue> CallRPC(const std::string& strMethod, const UniValue& params);

UniValue ConvertValues(const std::string &strMethod, const std::vector<std::string> &strParams)
{
    return RPCConvertValues(strMethod, strParams)
        .map_error([&](auto failure) {
            throw std::runtime_error(
                    FormatConversionFailure(strMethod, failure)
                    + examine(failure, match {
                        [](const UnknownRPCMethod&) { return std::string{}; },
                        [&](const auto&) {
                            auto helpMsg = CallRPC("help", ConvertValues("help", {strMethod}));
                            return "\n\n"
                                + (helpMsg.has_value()
                                   ? "Usage: " + helpMsg.value().get_str()
                                   : strprintf(
                                           "An error occurred while attempting to retrieve the "
                                           "help text for %s: %s",
                                           strMethod,
                                           helpMsg.error().get_str()));
                        }
                    }));
        })
        .value();
}

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

    // Obtain event base
    raii_event_base base = obtain_event_base();

    // Synchronously look up hostname
    raii_evhttp_connection evcon = obtain_evhttp_connection_base(base.get(), host, port);
    evhttp_connection_set_timeout(evcon.get(), GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));

    HTTPReply response;
    raii_evhttp_request req = obtain_evhttp_request(http_request_done, (void*)&response);
    if (req == NULL)
        throw std::runtime_error("create http request failed");
#if LIBEVENT_VERSION_NUMBER >= 0x02010300
    evhttp_request_set_error_cb(req.get(), http_error_cb);
#endif

    // Get credentials
    std::string strRPCUserColonPass;
    if (mapArgs["-rpcpassword"] == "") {
        // Try fall back to cookie-based authentication if no password is provided
        if (!GetAuthCookie(&strRPCUserColonPass)) {
            throw std::runtime_error(strprintf(
                _("Could not locate RPC credentials. No authentication cookie could be found,\n"
                  "and no rpcpassword is set in the configuration file (%s)."),
                    GetConfigFile(GetArg("-conf", BITCOIN_CONF_FILENAME)).string().c_str()));

        }
    } else {
        strRPCUserColonPass = mapArgs["-rpcuser"] + ":" + mapArgs["-rpcpassword"];
    }

    struct evkeyvalq* output_headers = evhttp_request_get_output_headers(req.get());
    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.get());
    assert(output_buffer);
    evbuffer_add(output_buffer, strRequest.data(), strRequest.size());

    int r = evhttp_make_request(evcon.get(), req.get(), EVHTTP_REQ_POST, "/");
    req.release(); // ownership moved to evcon in above call
    if (r != 0) {
        throw CConnectionFailed("send http request failed");
    }

    event_base_dispatch(base.get());

    if (response.status == 0)
        throw CConnectionFailed(strprintf("couldn't connect to server: %s (code %d)\n(make sure server is running and you are connecting to the correct RPC port)", http_errorstring(response.error), response.error));
    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");

    const UniValue error = find_value(reply, "error");

    return error.isNull()
        ? tl::expected<UniValue, UniValue>(find_value(reply, "result"))
        : tl::make_unexpected(error);
}

bool SetStdinEcho(bool enable = true)
{
#ifdef WIN32
    HANDLE hStdin = GetStdHandle(STD_INPUT_HANDLE);
    if (hStdin == INVALID_HANDLE_VALUE || hStdin == NULL) return false;
    DWORD mode;
    // if it's not a terminal then stdin won't be echoed, so that's not an error
    DWORD dwStdinType = GetFileType(hStdin) & ~FILE_TYPE_REMOTE;
    bool could_be_terminal = dwStdinType == FILE_TYPE_CHAR ||
                            (dwStdinType == FILE_TYPE_UNKNOWN && GetLastError() == NO_ERROR);
    if (!could_be_terminal || GetConsoleMode(hStdin, &mode) == 0) return true;

    if (!enable)
        mode &= ~ENABLE_ECHO_INPUT;
    else
        mode |= ENABLE_ECHO_INPUT;

    if (SetConsoleMode(hStdin, mode) == 0) return false;

#else
    struct termios tty;
    if (tcgetattr(STDIN_FILENO, &tty) != 0) {
        // if it's not a terminal then stdin won't be echoed, so that's not an error
        return errno == ENOTTY;
    }
    if (!enable)
        tty.c_lflag &= ~ECHO;
    else
        tty.c_lflag |= ECHO;

    if (tcsetattr(STDIN_FILENO, TCSANOW, &tty) != 0) return false;
#endif
    return true;
}

int CommandLineRPC(int argc, char *argv[])
{
    std::string strPrint;
    int nRet = 0;
    try {
        // Skip switches
        while (argc > 1 && IsSwitchChar(argv[1][0])) {
            argc--;
            argv++;
        }
        std::vector<std::string> args = std::vector<std::string>(&argv[1], &argv[argc]);
        if (GetBoolArg("-stdin", false)) {
            bool hide = false;
            if (args.size() > 0 && args[0] == "walletpassphrase") {
                if (!SetStdinEcho(false))
                    throw std::runtime_error("unable to set terminal to non-echoing");
                hide = true;
            }

            // Read one arg per line from stdin and append
            std::string line;
            while (std::getline(std::cin,line)) {
                args.push_back(line);
                if (hide) {
                    if (!SetStdinEcho(true))
                        throw std::runtime_error("unable to set terminal back to echoing");
                    hide = false;
                }
            }
        }
        if (args.size() < 1)
            throw std::runtime_error("too few parameters (need at least command)");
        std::string strMethod = args[0];
        auto params =
            ConvertValues(strMethod, std::vector<std::string>(args.begin()+1, args.end()));

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

                if (!reply.has_value()) {
                    auto error = reply.error();
                    // 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 {
                    auto result = reply.value();
                    // 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 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");
        return EXIT_FAILURE;
    }

    try {
        int ret = AppInitRPC(argc, argv);
        if (ret != CONTINUE_EXECUTION)
            return ret;
    }
    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;
}