#pragma once

#include <array>
#include <cstdint>
#include <functional>
#include <vector>

#include "host-ipmid/ipmid-api.h"

namespace oem
{
constexpr size_t groupMagicSize = 3;

using Group = std::array<uint8_t, groupMagicSize>;
using Number = uint32_t;  // smallest standard size >= 24.

// Handler signature includes ipmi cmd to support wildcard cmd match.
// Buffers and lengths exclude the OemGroup bytes in the IPMI message.
// dataLen supplies length of reqBuf upon call, and should be set to the
// length of replyBuf upon return - conventional in this code base.
using Handler = std::function<ipmi_ret_t(
                       ipmi_cmd_t,     // cmd byte
                       const uint8_t*, // reqBuf
                       uint8_t*,       // replyBuf
                       size_t*)>;      // dataLen

/// Router Interface class.
/// @brief Abstract Router Interface
class Router
{
    public:
        virtual ~Router() {}

        /// Enable message routing to begin.
        virtual void activate() = 0;

        /// Register a handler for given OEMNumber & cmd.
        /// Use IPMI_CMD_WILDCARD to catch any unregistered cmd
        /// for the given OEMNumber.
        ///
        /// @param[in] oen - the OEM Number.
        /// @param[in] cmd - the Command.
        /// @param[in] handler - the handler to call given that OEN and
        ///                      command.
        virtual void registerHandler(Number oen, ipmi_cmd_t cmd,
                                     Handler handler) = 0;
};

/// Expose mutable Router for configuration & activation.
///
/// @returns pointer to OEM Router to use.
Router* mutableRouter();

/// Convert a group to an OEN.
///
/// @param[in] oeg - request buffer for IPMI command.
/// @return the OEN.
constexpr Number toOemNumber(const uint8_t oeg[groupMagicSize])
{
    return (oeg[2] << 16) | (oeg[1] << 8) | oeg[0];
}

/// Given a Group convert to an OEN.
///
/// @param[in] oeg - OEM Group reference.
/// @return the OEN.
constexpr Number toOemNumber(const Group& oeg)
{
    return (oeg[2] << 16) | (oeg[1] << 8) | oeg[0];
}

/// Given an OEN, conver to the OEM Group.
///
/// @param[in] oen - the OEM Number.
/// @return the OEM Group.
constexpr Group toOemGroup(Number oen)
{
    return Group { static_cast<uint8_t>(oen),
                      static_cast<uint8_t>(oen >> 8),
                      static_cast<uint8_t>(oen >> 16) };
}

}  // namespace oem