// Copyright (c) 2010 Satoshi Nakamoto

// Copyright (c) 2009-present The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <rpc/request.h>

#include <common/args.h>

#include <crypto/hex_base.h>

#include <logging.h>

#include <random.h>

#include <rpc/protocol.h>

#include <util/fs.h>

#include <util/fs_helpers.h>

#include <util/strencodings.h>

#include <cstddef>

#include <fstream>

#include <span>

#include <stdexcept>

#include <string>

#include <system_error>

#include <utility>

#include <vector>

/**

 * JSON-RPC protocol.  Bitcoin speaks version 1.0 for maximum compatibility,

 * but uses JSON-RPC 1.1/2.0 standards for parts of the 1.0 standard that were

 * unspecified (HTTP errors and contents of 'error').

 *

 * 1.0 spec: https://www.jsonrpc.org/specification_v1

 * 1.2 spec: https://jsonrpc.org/historical/json-rpc-over-http.html

 *

 * If the server receives a request with the JSON-RPC 2.0 marker `{"jsonrpc": "2.0"}`

 * then Bitcoin will respond with a strictly specified response.

 * It will only return an HTTP error code if an actual HTTP error is encountered

 * such as the endpoint is not found (404) or the request is not formatted correctly (500).

 * Otherwise the HTTP code is always OK (200) and RPC errors will be included in the

 * response body.

 *

 * 2.0 spec: https://www.jsonrpc.org/specification

 *

 * Also see https://www.simple-is-better.org/rpc/#differences-between-1-0-and-2-0

 */

UniValue JSONRPCRequestObj(const std::string& strMethod, const UniValue& params, const UniValue& id)

{

    UniValue request(UniValue::VOBJ);

    request.pushKV("method", strMethod);

    request.pushKV("params", params);

    request.pushKV("id", id);

    request.pushKV("jsonrpc", "2.0");

    return request;

}

UniValue JSONRPCReplyObj(UniValue result, UniValue error, std::optional<UniValue> id, JSONRPCVersion jsonrpc_version)

{

    UniValue reply(UniValue::VOBJ);

    // Add JSON-RPC version number field in v2 only.

    if (jsonrpc_version == JSONRPCVersion::V2) reply.pushKV("jsonrpc", "2.0");

    // Add both result and error fields in v1, even though one will be null.

    // Omit the null field in v2.

    if (error.isNull()) {

        reply.pushKV("result", std::move(result));

        if (jsonrpc_version == JSONRPCVersion::V1_LEGACY) reply.pushKV("error", NullUniValue);

    } else {

        if (jsonrpc_version == JSONRPCVersion::V1_LEGACY) reply.pushKV("result", NullUniValue);

        reply.pushKV("error", std::move(error));

    }

    if (id.has_value()) reply.pushKV("id", std::move(id.value()));

    return reply;

}

UniValue JSONRPCError(int code, const std::string& message)

{

    UniValue error(UniValue::VOBJ);

    error.pushKV("code", code);

    error.pushKV("message", message);

    return error;

}

/** Username used when cookie authentication is in use (arbitrary, only for

 * recognizability in debugging/logging purposes)

 */

static const std::string COOKIEAUTH_USER = "__cookie__";

/** Default name for auth cookie file */

static const char* const COOKIEAUTH_FILE = ".cookie";

/** Get name of RPC authentication cookie file */

static fs::path GetAuthCookieFile(bool temp=false)

{

    fs::path arg = gArgs.GetPathArg("-rpccookiefile", COOKIEAUTH_FILE);

    if (arg.empty()) {

        return {}; // -norpccookiefile was specified

    }

    if (temp) {

        arg += ".tmp";

    }

    return AbsPathForConfigVal(gArgs, arg);

}

static bool g_generated_cookie = false;

AuthCookieResult GenerateAuthCookie(const std::optional<fs::perms>& cookie_perms,

                                    std::string& user,

                                    std::string& pass)

{

    const size_t COOKIE_SIZE = 32;

    unsigned char rand_pwd[COOKIE_SIZE];

    GetRandBytes(rand_pwd);

    const std::string rand_pwd_hex{HexStr(rand_pwd)};

    /** the umask determines what permissions are used to create this file -

     * these are set to 0077 in common/system.cpp.

     */

    std::ofstream file;

    fs::path filepath_tmp = GetAuthCookieFile(true);

    if (filepath_tmp.empty()) {

        return AuthCookieResult::Disabled; // -norpccookiefile

    }

    file.open(filepath_tmp.std_path());

    if (!file.is_open()) {

        LogWarning("Unable to open cookie authentication file %s for writing", fs::PathToString(filepath_tmp));

        return AuthCookieResult::Error;

    }

    file << COOKIEAUTH_USER << ":" << rand_pwd_hex;

    file.close();

    fs::path filepath = GetAuthCookieFile(false);

    if (!RenameOver(filepath_tmp, filepath)) {

        LogWarning("Unable to rename cookie authentication file %s to %s", fs::PathToString(filepath_tmp), fs::PathToString(filepath));

        return AuthCookieResult::Error;

    }

    if (cookie_perms) {

        std::error_code code;

        fs::permissions(filepath, cookie_perms.value(), fs::perm_options::replace, code);

        if (code) {

            LogWarning("Unable to set permissions on cookie authentication file %s", fs::PathToString(filepath));

            return AuthCookieResult::Error;

        }

    }

    g_generated_cookie = true;

    LogInfo("Generated RPC authentication cookie %s\n", fs::PathToString(filepath));

    LogInfo("Permissions used for cookie: %s\n", PermsToSymbolicString(fs::status(filepath).permissions()));

    user = COOKIEAUTH_USER;

    pass = rand_pwd_hex;

    return AuthCookieResult::Ok;

}

AuthCookieResult GetAuthCookie(std::string& cookie_out)

{

    std::ifstream file;

    fs::path filepath = GetAuthCookieFile();

    if (filepath.empty()) {

        return AuthCookieResult::Disabled; // -norpccookiefile

    }

    file.open(filepath.std_path());

    if (!file.is_open()) {

        return AuthCookieResult::Error;

    }

    std::getline(file, cookie_out);

    file.close();

    return AuthCookieResult::Ok;

}

void DeleteAuthCookie()

{

    try {

        if (g_generated_cookie) {

            // Delete the cookie file if it was generated by this process

            fs::remove(GetAuthCookieFile());

        }

    } catch (const fs::filesystem_error& e) {

        LogWarning("Unable to remove random auth cookie file %s: %s\n", fs::PathToString(e.path1()), e.code().message());

    }

}

std::vector<UniValue> JSONRPCProcessBatchReply(const UniValue& in)

{

    if (!in.isArray()) {

        throw std::runtime_error("Batch must be an array");

    }

    const size_t num {in.size()};

    std::vector<UniValue> batch(num);

    for (const UniValue& rec : in.getValues()) {

        if (!rec.isObject()) {

            throw std::runtime_error("Batch member must be an object");

        }

        size_t id = rec["id"].getInt<int>();

        if (id >= num) {

            throw std::runtime_error("Batch member id is larger than batch size");

        }

        batch[id] = rec;

    }

    return batch;

}

void JSONRPCRequest::parse(const UniValue& valRequest)

{

    // Parse request

    if (!valRequest.isObject())

        throw JSONRPCError(RPC_INVALID_REQUEST, "Invalid Request object");

    const UniValue& request = valRequest.get_obj();

    // Parse id now so errors from here on will have the id

    if (request.exists("id")) {

        id = request.find_value("id");

    } else {

        id = std::nullopt;

    }

    // Check for JSON-RPC 2.0 (default 1.1)

    m_json_version = JSONRPCVersion::V1_LEGACY;

    const UniValue& jsonrpc_version = request.find_value("jsonrpc");

    if (!jsonrpc_version.isNull()) {

        if (!jsonrpc_version.isStr()) {

            throw JSONRPCError(RPC_INVALID_REQUEST, "jsonrpc field must be a string");

        }

        // The "jsonrpc" key was added in the 2.0 spec, but some older documentation

        // incorrectly included {"jsonrpc":"1.0"} in a request object, so we

        // maintain that for backwards compatibility.

        if (jsonrpc_version.get_str() == "1.0") {

            m_json_version = JSONRPCVersion::V1_LEGACY;

        } else if (jsonrpc_version.get_str() == "2.0") {

            m_json_version = JSONRPCVersion::V2;

        } else {

            throw JSONRPCError(RPC_INVALID_REQUEST, "JSON-RPC version not supported");

        }

    }

    // Parse method

    const UniValue& valMethod{request.find_value("method")};

    if (valMethod.isNull())

        throw JSONRPCError(RPC_INVALID_REQUEST, "Missing method");

    if (!valMethod.isStr())

        throw JSONRPCError(RPC_INVALID_REQUEST, "Method must be a string");

    strMethod = valMethod.get_str();

    const std::string log_id{id && !id->isNull() ? SanitizeString(id->getValStr()) : ""};

    if (fLogIPs)

        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s peeraddr=%s id=%s", SanitizeString(strMethod),

            this->authUser, this->peerAddr, log_id);

    else

        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s id=%s", SanitizeString(strMethod), this->authUser,

            log_id);

    // Parse params

    const UniValue& valParams{request.find_value("params")};

    if (valParams.isArray() || valParams.isObject())

        params = valParams;

    else if (valParams.isNull())

        params = UniValue(UniValue::VARR);

    else

        throw JSONRPCError(RPC_INVALID_REQUEST, "Params must be an array or object");

}