//---------------------------------------------------------------------------
//
//	SCSI Target Emulator RaSCSI Reloaded
//	for Raspberry Pi
//
//  Copyright (C) 2020 akuker
//	Copyright (C) 2014-2020 GIMONS
//	Copyright (C) 2001-2006 ＰＩ．(ytanaka@ipc-tokai.or.jp)
//
//  Licensed under the BSD 3-Clause License. 
//  See LICENSE file in the project root folder.
//
//  [ Emulation of the DaynaPort SCSI Link Ethernet interface ]
//
//  This design is derived from the SLINKCMD.TXT file, as well as David Kuder's 
//  Tiny SCSI Emulator
//    - SLINKCMD: http://www.bitsavers.org/pdf/apple/scsi/dayna/daynaPORT/SLINKCMD.TXT
//    - Tiny SCSI : https://hackaday.io/project/18974-tiny-scsi-emulator
//
//  Special thanks to @PotatoFi for loaning me his Farallon EtherMac for
//  this development. (Farallon's EtherMac is a re-branded DaynaPort
//  SCSI/Link-T).
//
//  This does NOT include the file system functionality that is present
//  in the Sharp X68000 host bridge.
//
//  Note: This requires the DaynaPort SCSI Link driver.
//---------------------------------------------------------------------------
#pragma once

#include "os.h"
#include "disk.h"
#include "ctapdriver.h"
#include <string>

//===========================================================================
//
//	DaynaPort SCSI Link
//
//===========================================================================
class SCSIDaynaPort: public Disk
{

public:
	SCSIDaynaPort();
	~SCSIDaynaPort() final;
	SCSIDaynaPort(SCSIDaynaPort&) = delete;
	SCSIDaynaPort& operator=(const SCSIDaynaPort&) = delete;

	bool Init(const unordered_map<string, string>&) override;
	void Open(const Filepath& path) override;

	// Commands
	vector<BYTE> InquiryInternal() const override;
	int Read(const DWORD *cdb, BYTE *, uint64_t) override;
	bool WriteBytes(const DWORD *, const BYTE *, uint64_t);
	int WriteCheck(uint64_t block) override;

	int RetrieveStats(const DWORD *cdb, BYTE *buffer) const;
	bool EnableInterface(const DWORD *cdb);

	void SetMacAddr(const DWORD *cdb, BYTE *buffer);	// Set MAC address

	void TestUnitReady() override;
	void Read6() override;
	void Write6() override;
	void RetrieveStatistics();
	void SetInterfaceMode();
	void SetMcastAddr();
	void EnableInterface();
	int GetSendDelay() const override;

	bool Dispatch() override;

	const int DAYNAPORT_BUFFER_SIZE = 0x1000000;

	static const BYTE CMD_SCSILINK_STATS        = 0x09;
	static const BYTE CMD_SCSILINK_ENABLE       = 0x0E;
	static const BYTE CMD_SCSILINK_SET          = 0x0C;
	static const BYTE CMD_SCSILINK_SETMODE      = 0x80;
	static const BYTE CMD_SCSILINK_SETMAC       = 0x40;

	// When we're reading the Linux tap device, most of the messages will not be for us, so we
	// need to filter through those. However, we don't want to keep re-reading the packets
	// indefinitely. So, we'll pick a large-ish number that will cause the emulated DaynaPort
	// to respond with "no data" after MAX_READ_RETRIES tries.
	static const int MAX_READ_RETRIES               = 50;

	// The READ response has a header which consists of:
	//   2 bytes - payload size
	//   4 bytes - status flags
	static const DWORD DAYNAPORT_READ_HEADER_SZ = 2 + 4;

private:
	using super = Disk;

	Dispatcher<SCSIDaynaPort> dispatcher;

	using scsi_cmd_daynaport_write_t = struct __attribute__((packed)) {
		BYTE operation_code;
		BYTE misc_cdb_information;
		BYTE logical_block_address;
		uint16_t length;
		BYTE format;
	};

	enum read_data_flags_t : uint32_t {
		e_no_more_data = 0x00000000,
		e_more_data_available = 0x00000001,
		e_dropped_packets = 0xFFFFFFFF,
	};

	using scsi_resp_read_t = struct __attribute__((packed)) {
		uint32_t length;
		read_data_flags_t flags;
		BYTE pad;
		BYTE data[ETH_FRAME_LEN + sizeof(uint32_t)]; // Frame length + 4 byte CRC
	};

	using scsi_resp_link_stats_t = struct __attribute__((packed)) {
		BYTE mac_address[6];
		uint32_t frame_alignment_errors;
		uint32_t crc_errors;
		uint32_t frames_lost;
	};

	scsi_resp_link_stats_t m_scsi_link_stats = {
		.mac_address = { 0x00, 0x80, 0x19, 0x10, 0x98, 0xE3 },//MAC address of @PotatoFi's DayanPort
		.frame_alignment_errors = 0,
		.crc_errors = 0,
		.frames_lost = 0,
	};

	const BYTE m_daynacom_mac_prefix[3] = { 0x00, 0x80, 0x19 };

	CTapDriver *m_tap = nullptr;
										// TAP driver
	bool m_bTapEnable = false;
										// TAP valid flag
	BYTE m_mac_addr[6];
										// MAC Address
	static const BYTE m_bcast_addr[6];
	static const BYTE m_apple_talk_addr[6];
};