#include <xrpld/rpc/detail/Handler.h>
#include <xrpld/rpc/handlers/Handlers.h>
#include <xrpld/rpc/handlers/server_info/Version.h>

#include <xrpl/basics/contract.h>
#include <xrpl/protocol/ApiVersion.h>

#include <map>

namespace xrpl {
namespace RPC {
namespace {

/** Adjust an old-style handler to be call-by-reference. */
template <typename Function>
Handler::Method<Json::Value>
byRef(Function const& f)
{
    return [f](JsonContext& context, Json::Value& result) {
        result = f(context);
        if (result.type() != Json::objectValue)
        {
            // LCOV_EXCL_START
            UNREACHABLE("xrpl::RPC::byRef : result is object");
            result = RPC::makeObjectValue(result);
            // LCOV_EXCL_STOP
        }

        return Status();
    };
}

template <class Object, class HandlerImpl>
Status
handle(JsonContext& context, Object& object)
{
    XRPL_ASSERT(
        context.apiVersion >= HandlerImpl::minApiVer &&
            context.apiVersion <= HandlerImpl::maxApiVer,
        "xrpl::RPC::handle : valid API version");
    HandlerImpl handler(context);

    auto status = handler.check();
    if (status)
    {
        status.inject(object);
    }
    else
    {
        handler.writeResult(object);
    }
    return status;
}

template <typename HandlerImpl>
Handler
handlerFrom()
{
    return {
        HandlerImpl::name,
        &handle<Json::Value, HandlerImpl>,
        HandlerImpl::role,
        HandlerImpl::condition,
        HandlerImpl::minApiVer,
        HandlerImpl::maxApiVer};
}

Handler const handlerArray[]{
    // Some handlers not specified here are added to the table via addHandler()
    // Request-response methods
    {"account_info", byRef(&doAccountInfo), Role::USER, NO_CONDITION},
    {"account_currencies", byRef(&doAccountCurrencies), Role::USER, NO_CONDITION},
    {"account_lines", byRef(&doAccountLines), Role::USER, NO_CONDITION},
    {"account_channels", byRef(&doAccountChannels), Role::USER, NO_CONDITION},
    {"account_nfts", byRef(&doAccountNFTs), Role::USER, NO_CONDITION},
    {"account_objects", byRef(&doAccountObjects), Role::USER, NO_CONDITION},
    {"account_offers", byRef(&doAccountOffers), Role::USER, NO_CONDITION},
    {"account_tx", byRef(&doAccountTx), Role::USER, NO_CONDITION},
    {"amm_info", byRef(&doAMMInfo), Role::USER, NO_CONDITION},
    {"blacklist", byRef(&doBlackList), Role::ADMIN, NO_CONDITION},
    {"book_changes", byRef(&doBookChanges), Role::USER, NO_CONDITION},
    {"book_offers", byRef(&doBookOffers), Role::USER, NO_CONDITION},
    {"can_delete", byRef(&doCanDelete), Role::ADMIN, NO_CONDITION},
    {"channel_authorize", byRef(&doChannelAuthorize), Role::USER, NO_CONDITION},
    {"channel_verify", byRef(&doChannelVerify), Role::USER, NO_CONDITION},
    {"connect", byRef(&doConnect), Role::ADMIN, NO_CONDITION},
    {"consensus_info", byRef(&doConsensusInfo), Role::ADMIN, NO_CONDITION},
    {"deposit_authorized", byRef(&doDepositAuthorized), Role::USER, NO_CONDITION},
    {"feature", byRef(&doFeature), Role::USER, NO_CONDITION},
    {"fee", byRef(&doFee), Role::USER, NEEDS_CURRENT_LEDGER},
    {"fetch_info", byRef(&doFetchInfo), Role::ADMIN, NO_CONDITION},
    {"gateway_balances", byRef(&doGatewayBalances), Role::USER, NO_CONDITION},
    {"get_counts", byRef(&doGetCounts), Role::ADMIN, NO_CONDITION},
    {"get_aggregate_price", byRef(&doGetAggregatePrice), Role::USER, NO_CONDITION},
    {"ledger_accept", byRef(&doLedgerAccept), Role::ADMIN, NEEDS_CURRENT_LEDGER},
    {"ledger_cleaner", byRef(&doLedgerCleaner), Role::ADMIN, NEEDS_NETWORK_CONNECTION},
    {"ledger_closed", byRef(&doLedgerClosed), Role::USER, NEEDS_CLOSED_LEDGER},
    {"ledger_current", byRef(&doLedgerCurrent), Role::USER, NEEDS_CURRENT_LEDGER},
    {"ledger_data", byRef(&doLedgerData), Role::USER, NO_CONDITION},
    {"ledger_entry", byRef(&doLedgerEntry), Role::USER, NO_CONDITION},
    {"ledger_header", byRef(&doLedgerHeader), Role::USER, NO_CONDITION, 1, 1},
    {"ledger_request", byRef(&doLedgerRequest), Role::ADMIN, NO_CONDITION},
    {"log_level", byRef(&doLogLevel), Role::ADMIN, NO_CONDITION},
    {"logrotate", byRef(&doLogRotate), Role::ADMIN, NO_CONDITION},
    {"manifest", byRef(&doManifest), Role::USER, NO_CONDITION},
    {"nft_buy_offers", byRef(&doNFTBuyOffers), Role::USER, NO_CONDITION},
    {"nft_sell_offers", byRef(&doNFTSellOffers), Role::USER, NO_CONDITION},
    {"noripple_check", byRef(&doNoRippleCheck), Role::USER, NO_CONDITION},
    {"owner_info", byRef(&doOwnerInfo), Role::USER, NEEDS_CURRENT_LEDGER},
    {"peers", byRef(&doPeers), Role::ADMIN, NO_CONDITION},
    {"path_find", byRef(&doPathFind), Role::USER, NEEDS_CURRENT_LEDGER},
    {"ping", byRef(&doPing), Role::USER, NO_CONDITION},
    {"print", byRef(&doPrint), Role::ADMIN, NO_CONDITION},
    //      {   "profile",              byRef (&doProfile), Role::USER,
    //      NEEDS_CURRENT_LEDGER  },
    {"random", byRef(&doRandom), Role::USER, NO_CONDITION},
    {"peer_reservations_add", byRef(&doPeerReservationsAdd), Role::ADMIN, NO_CONDITION},
    {"peer_reservations_del", byRef(&doPeerReservationsDel), Role::ADMIN, NO_CONDITION},
    {"peer_reservations_list", byRef(&doPeerReservationsList), Role::ADMIN, NO_CONDITION},
    {"ripple_path_find", byRef(&doRipplePathFind), Role::USER, NO_CONDITION},
    {"server_definitions", byRef(&doServerDefinitions), Role::USER, NO_CONDITION},
    {"server_info", byRef(&doServerInfo), Role::USER, NO_CONDITION},
    {"server_state", byRef(&doServerState), Role::USER, NO_CONDITION},
    {"sign", byRef(&doSign), Role::USER, NO_CONDITION},
    {"sign_for", byRef(&doSignFor), Role::USER, NO_CONDITION},
    {"simulate", byRef(&doSimulate), Role::USER, NEEDS_CURRENT_LEDGER},
    {"stop", byRef(&doStop), Role::ADMIN, NO_CONDITION},
    {"submit", byRef(&doSubmit), Role::USER, NEEDS_CURRENT_LEDGER},
    {"submit_multisigned", byRef(&doSubmitMultiSigned), Role::USER, NEEDS_CURRENT_LEDGER},
    {"transaction_entry", byRef(&doTransactionEntry), Role::USER, NO_CONDITION},
    {"tx", byRef(&doTxJson), Role::USER, NEEDS_NETWORK_CONNECTION},
    {"tx_history", byRef(&doTxHistory), Role::USER, NO_CONDITION, 1, 1},
    {"tx_reduce_relay", byRef(&doTxReduceRelay), Role::USER, NO_CONDITION},
    {"unl_list", byRef(&doUnlList), Role::ADMIN, NO_CONDITION},
    {"validation_create", byRef(&doValidationCreate), Role::ADMIN, NO_CONDITION},
    {"validators", byRef(&doValidators), Role::ADMIN, NO_CONDITION},
    {"validator_list_sites", byRef(&doValidatorListSites), Role::ADMIN, NO_CONDITION},
    {"validator_info", byRef(&doValidatorInfo), Role::ADMIN, NO_CONDITION},
    {"vault_info", byRef(&doVaultInfo), Role::USER, NO_CONDITION},
    {"wallet_propose", byRef(&doWalletPropose), Role::ADMIN, NO_CONDITION},
    // Event methods
    {"subscribe", byRef(&doSubscribe), Role::USER, NO_CONDITION},
    {"unsubscribe", byRef(&doUnsubscribe), Role::USER, NO_CONDITION},
};

class HandlerTable
{
private:
    using handler_table_t = std::multimap<std::string, Handler>;

    // Use with equal_range to enforce that API range of a newly added handler
    // does not overlap with API range of an existing handler with same name
    [[nodiscard]] static bool
    overlappingApiVersion(
        std::pair<handler_table_t::iterator, handler_table_t::iterator> range,
        unsigned minVer,
        unsigned maxVer)
    {
        XRPL_ASSERT(minVer <= maxVer, "xrpl::RPC::HandlerTable : valid API version range");
        XRPL_ASSERT(
            maxVer <= RPC::apiMaximumValidVersion,
            "xrpl::RPC::HandlerTable : valid max API version");

        return std::any_of(
            range.first,
            range.second,  //
            [minVer, maxVer](auto const& item) {
                return item.second.minApiVer_ <= maxVer && item.second.maxApiVer_ >= minVer;
            });
    }

    template <std::size_t N>
    explicit HandlerTable(Handler const (&entries)[N])
    {
        for (auto const& entry : entries)
        {
            if (overlappingApiVersion(
                    table_.equal_range(entry.name_), entry.minApiVer_, entry.maxApiVer_))
            {
                LogicError(
                    std::string("Handler for ") + entry.name_ +
                    " overlaps with an existing handler");
            }

            table_.insert({entry.name_, entry});
        }

        // This is where the new-style handlers are added.
        addHandler<LedgerHandler>();
        addHandler<VersionHandler>();
    }

public:
    static HandlerTable const&
    instance()
    {
        static HandlerTable const handlerTable(handlerArray);
        return handlerTable;
    }

    [[nodiscard]] Handler const*
    getHandler(unsigned version, bool betaEnabled, std::string const& name) const
    {
        if (version < RPC::apiMinimumSupportedVersion ||
            version > (betaEnabled ? RPC::apiBetaVersion : RPC::apiMaximumSupportedVersion))
            return nullptr;

        auto const range = table_.equal_range(name);
        auto const i = std::find_if(range.first, range.second, [version](auto const& entry) {
            return entry.second.minApiVer_ <= version && version <= entry.second.maxApiVer_;
        });

        return i == range.second ? nullptr : &i->second;
    }

    [[nodiscard]] std::set<char const*>
    getHandlerNames() const
    {
        std::set<char const*> ret;
        for (auto const& i : table_)
            ret.insert(i.second.name_);

        return ret;
    }

private:
    handler_table_t table_;

    template <class HandlerImpl>
    void
    addHandler()
    {
        static_assert(HandlerImpl::minApiVer <= HandlerImpl::maxApiVer);
        static_assert(HandlerImpl::maxApiVer <= RPC::apiMaximumValidVersion);
        static_assert(RPC::apiMinimumSupportedVersion <= HandlerImpl::minApiVer);

        if (overlappingApiVersion(
                table_.equal_range(HandlerImpl::name),
                HandlerImpl::minApiVer,
                HandlerImpl::maxApiVer))
        {
            LogicError(
                std::string("Handler for ") + HandlerImpl::name +
                " overlaps with an existing handler");
        }

        table_.insert({HandlerImpl::name, handlerFrom<HandlerImpl>()});
    }
};

}  // namespace

Handler const*
getHandler(unsigned version, bool betaEnabled, std::string const& name)
{
    return HandlerTable::instance().getHandler(version, betaEnabled, name);
}

std::set<char const*>
getHandlerNames()
{
    return HandlerTable::instance().getHandlerNames();
}

}  // namespace RPC
}  // namespace xrpl