/*
    mscp_server.hpp: Implementation of a simple MSCP server.

    Copyright Vulcan Inc. 2019 via Living Computers: Museum + Labs, Seattle, WA.
    Contributed under the BSD 2-clause license.
*/

#pragma once

#include <stdint.h>
#include <memory>

class uda_c;
class Message;
class mscp_drive_c;

// Builds a uint32_t containing the status, flags, and endcode for a response message,
// used to simplify returning the appropriate status bits from command functions.
#define STATUS(status, modifier, flags) ((flags) << 8) | (((status) | ((modifier) * 0x20)) << 16)

#define GET_STATUS(status) (((status) >> 16) & 0xffff)
#define GET_FLAGS(status) (((status) >> 8) & 0xff)

#define MAX_CREDITS 14
#define INIT_CREDITS 1

//
// ControlMessageHeader encapsulates the standard MSCP control
// message header: a 12-byte header followed by up to 36 bytes of
// parameters.
// Note: This struct (and many others like it in this code) assumes
// little-endian byte orderings.  Probably not a big deal unless this
// someday runs on something other than a Beaglebone.
//
#pragma pack(push,1)
struct ControlMessageHeader
{
    uint32_t ReferenceNumber;
    uint16_t UnitNumber;
    uint16_t Reserved;

    union
    {
        struct
        {
            uint8_t Opcode : 8;
            uint8_t Reserved : 8;
            uint16_t Modifiers : 16;
        } Command;

        struct
        {
            uint8_t Endcode : 8;
            uint8_t Flags : 8;
            uint16_t Status : 16;
        } End;
    } Word3;

    // M9312 DU boot loader writes invalid big messages sizes.
    // Temporary patch: enlarge buffer behind all reasonable limits.
    // uint8_t Parameters[512];
    uint8_t Parameters[10240];	// overkill
};
#pragma pack(pop)

// Size in bytes of the non-parameter portion of a ControlMessageHeader
#define HEADER_SIZE  12

enum Opcodes
{
    ABORT = 0x1,
    ACCESS = 0x10,
    AVAILABLE = 0x8,
    COMPARE_HOST_DATA = 0x20,
    DETERMINE_ACCESS_PATHS = 0x0b,
    ERASE = 0x12,
    GET_COMMAND_STATUS = 0x2,
    GET_UNIT_STATUS = 0x3,
    ONLINE = 0x9,
    READ = 0x21,
    REPLACE = 0x14,
    SET_CONTROLLER_CHARACTERISTICS = 0x4,
    SET_UNIT_CHARACTERISTICS = 0xa,
    WRITE = 0x22
};

enum Endcodes
{
    END = 0x80,
    SERIOUS_EXCEPTION = 0x7,
};

enum Status
{
    SUCCESS = 0x0,
    INVALID_COMMAND = 0x1,
    COMMAND_ABORTED = 0x2,
    UNIT_OFFLINE = 0x3,
    UNIT_AVAILABLE = 0x4,
    MEDIA_FORMAT_ERROR = 0x5,
    WRITE_PROTECTED = 0x6,
    COMPARE_ERROR = 0x7,
    DATA_ERROR = 0x8,
    HOST_BUFFER_ACCESS_ERROR = 0x9,
    CONTROLLER_ERROR = 0xa,
    DRIVE_ERROR = 0xb,
    DIAGNOSTIC_MESSAGE = 0x1f
};

enum SuccessSubcodes
{
    NORMAL = 0x0,
    SPIN_DOWN_IGNORED = 0x20,
    STILL_CONNECTED = 0x40,
    DUPLICATE_UNIT_NUMBER = 0x80,
    ALREADY_ONLINE = 0x100,
    STILL_ONLINE = 0x200,
};

enum UnitOfflineSubcodes
{
    UNIT_UNKNOWN = 0x0,
    NO_VOLUME = 0x1,
    UNIT_INOPERATIVE = 0x2,
    DUPLICATE_UNIT = 0x4,
    UNIT_DISABLED = 0x8,
    EXCLUSIVE = 0x10,
};

enum MessageTypes
{
    Sequential = 0,
    Datagram = 1,
    CreditNotification = 2,
    Maintenance = 15,
};

//
// This inherits from device_c solely so the logging macros work.
//
class mscp_server : public device_c
{
public:
    mscp_server(uda_c *port);
    ~mscp_server();
	bool on_param_changed(parameter_c *param) override ;

public:
    void Reset(void);
    void InitPolling(void);
    void Poll(void);

public:
    void on_power_changed(void) override {}
    void on_init_changed(void) override {}

private:
    uint32_t Abort(void);
    uint32_t Access(std::shared_ptr<Message> message, uint16_t unitNumber);
    uint32_t Available(uint16_t unitNumber, uint16_t modifiers);
    uint32_t CompareHostData(std::shared_ptr<Message> message, uint16_t unitNumber);
    uint32_t DetermineAccessPaths(uint16_t unitNumber);
    uint32_t Erase(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint32_t GetCommandStatus(std::shared_ptr<Message> message);
    uint32_t GetUnitStatus(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint32_t Online(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint32_t SetControllerCharacteristics(std::shared_ptr<Message> message);
    uint32_t SetUnitCharacteristics(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint32_t Read(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint32_t Replace(std::shared_ptr<Message> message, uint16_t unitNumber);
    uint32_t Write(std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);

    uint32_t SetUnitCharacteristicsInternal(
        std::shared_ptr<Message> message,
        uint16_t unitNumber,
        uint16_t modifiers,
        bool bringOnline);
    uint32_t DoDiskTransfer(uint16_t operation, std::shared_ptr<Message> message, uint16_t unitNumber, uint16_t modifiers);
    uint8_t* GetParameterPointer(std::shared_ptr<Message> message);
    mscp_drive_c* GetDrive(uint32_t unitNumber);

private:
    void StartPollingThread(void);
    void AbortPollingThread(void);

private:
    uint32_t _hostTimeout;
    uint32_t _controllerFlags;

private:
    uda_c* _port;

    enum PollingState
    {
        Wait = 0,
        Run,
        InitRestart,
        InitRun
    };

    bool _abort_polling;
    PollingState _pollState;

    pthread_t polling_pthread;
    pthread_cond_t polling_cond;
    pthread_mutex_t polling_mutex;

    // Credits available
    uint8_t _credits;
};