/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-22 divingkatae and maximum
                      (theweirdo)     spatium

(Contact divingkatae#1017 or powermax#2286 on Discord for more info)

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/** @file SCSI CD-ROM emulation. */

#include <devices/common/scsi/scsi.h>
#include <devices/common/scsi/scsicdrom.h>
#include <devices/deviceregistry.h>
#include <machines/machineproperties.h>
#include <loguru.hpp>

#include <cinttypes>
#include <cstring>
#include <stdio.h>
#include <sys/stat.h>

using namespace std;

static char cdrom_vendor_sony_id[] = "SONY    ";
static char cdu8003a_product_id[]  = "CD-ROM CDU-8003A";
static char cdu8003a_revision_id[] = "1.9a";

ScsiCdrom::ScsiCdrom(int my_id) : ScsiDevice(my_id)
{
    supports_types(HWCompType::SCSI_DEV);

    this->sector_size = 2048;

    this->pre_xfer_action  = nullptr;
    this->post_xfer_action = nullptr;
}

void ScsiCdrom::insert_image(std::string filename)
{
    this->cdr_img.open(filename, ios::out | ios::in | ios::binary);

    struct stat stat_buf;
    int rc = stat(filename.c_str(), &stat_buf);
    if (!rc) {
        this->img_size = stat_buf.st_size;
        this->total_frames = (this->img_size + this->sector_size - 1) / this->sector_size;

        // create single track descriptor
        this->tracks[0]  = {.trk_num = 1, .adr_ctrl = 0x14, .start_lba = 0};
        this->num_tracks = 1;

        // create Lead-out descriptor containing all data
        this->tracks[1] = {.trk_num = LEAD_OUT_TRK_NUM, .adr_ctrl = 0x14,
            .start_lba = static_cast<uint32_t>(this->total_frames)};
    } else {
        ABORT_F("SCSI-CDROM: could not determine file size using stat()");
    }
    this->cdr_img.seekg(0, std::ios_base::beg);
}

void ScsiCdrom::process_command()
{
    uint32_t lba, xfer_len;

    this->pre_xfer_action  = nullptr;
    this->post_xfer_action = nullptr;

    // assume successful command execution
    this->status = ScsiStatus::GOOD;

    switch (cmd_buf[0]) {
    case ScsiCommand::TEST_UNIT_READY:
        this->switch_phase(ScsiPhase::STATUS);
        break;
    case ScsiCommand::READ_6:
        lba = ((cmd_buf[1] & 0x1F) << 16) + (cmd_buf[2] << 8) + cmd_buf[3];
        this->read(lba, cmd_buf[4], 6);
        break;
    case ScsiCommand::INQUIRY:
        this->inquiry();
        break;
    case ScsiCommand::MODE_SELECT_6:
        this->incoming_size = this->cmd_buf[4];
        this->switch_phase(ScsiPhase::DATA_OUT);
        break;
    case ScsiCommand::MODE_SENSE_6:
        this->mode_sense();
        break;
    case ScsiCommand::PREVENT_ALLOW_MEDIUM_REMOVAL:
        this->eject_allowed = (this->cmd_buf[4] & 1) == 0;
        this->switch_phase(ScsiPhase::STATUS);
        break;
    case ScsiCommand::READ_10:
        lba      = (cmd_buf[2] << 24) + (cmd_buf[3] << 16) + (cmd_buf[4] << 8) + cmd_buf[5];
        xfer_len = (cmd_buf[7] << 8) + cmd_buf[8];
        read(lba, xfer_len, 10);
        break;
    case ScsiCommand::READ_TOC:
        this->read_toc();
        break;
    default:
        ABORT_F("SCSI_CDROM: unsupported command %d", this->cmd_buf[0]);
    }
}

bool ScsiCdrom::prepare_data()
{
    switch (this->cur_phase) {
    case ScsiPhase::DATA_IN:
        this->data_ptr  = (uint8_t*)this->data_buf;
        this->data_size = this->bytes_out;
        break;
    case ScsiPhase::DATA_OUT:
        this->data_ptr  = (uint8_t*)this->data_buf;
        this->data_size = 0;
        break;
    case ScsiPhase::STATUS:
        break;
    default:
        LOG_F(WARNING, "SCSI_CDROM: unexpected phase in prepare_data");
        return false;
    }
    return true;
}

void ScsiCdrom::read(const uint32_t lba, const uint16_t transfer_len, const uint8_t cmd_len)
{
    uint32_t transfer_size = transfer_len;

    std::memset(this->data_buf, 0, sizeof(this->data_buf));

    if (cmd_len == 6 && transfer_len == 0) {
        transfer_size = 256;
    }

    transfer_size *= this->sector_size;
    uint64_t device_offset = lba * this->sector_size;

    this->cdr_img.seekg(device_offset, this->cdr_img.beg);
    this->cdr_img.read(this->data_buf, transfer_size);

    this->bytes_out = transfer_size;
    this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;

    this->switch_phase(ScsiPhase::DATA_IN);
}

void ScsiCdrom::inquiry()
{
    int page_num  = cmd_buf[2];
    int alloc_len = cmd_buf[4];

    if (page_num) {
        ABORT_F("SCSI_CDROM: invalid page number in INQUIRY");
    }

    if (alloc_len > 36) {
        LOG_F(WARNING, "SCSI_CDROM: more than 36 bytes requested in INQUIRY");
    }

    this->data_buf[0] =    5; // device type: CD-ROM
    this->data_buf[1] = 0x80; // removable media
    this->data_buf[2] =    2; // ANSI version: SCSI-2
    this->data_buf[3] =    1; // response data format
    this->data_buf[4] = 0x1F; // additional length
    this->data_buf[5] =    0;
    this->data_buf[6] =    0;
    this->data_buf[7] = 0x18; // supports synchronous xfers and linked commands
    std::memcpy(&this->data_buf[8],  cdrom_vendor_sony_id, 8);
    std::memcpy(&this->data_buf[16], cdu8003a_product_id, 16);
    std::memcpy(&this->data_buf[32], cdu8003a_revision_id, 4);

    this->bytes_out = 36;
    this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;

    this->switch_phase(ScsiPhase::DATA_IN);
}

static char Apple_Copyright_Page_Data[] = "APPLE COMPUTER, INC   ";

void ScsiCdrom::mode_sense()
{
    uint8_t page_code = this->cmd_buf[2] & 0x3F;
    uint8_t alloc_len = this->cmd_buf[4];

    int num_blocks = (this->img_size + this->sector_size) / this->sector_size;

    this->data_buf[ 0] =   13; // initial data size
    this->data_buf[ 1] =    0; // medium type
    this->data_buf[ 2] = 0x80; // medium is write protected
    this->data_buf[ 3] =    8; // block description length

    this->data_buf[ 4] =    0; // density code
    this->data_buf[ 5] = (num_blocks >> 16) & 0xFFU;
    this->data_buf[ 6] = (num_blocks >>  8) & 0xFFU;
    this->data_buf[ 7] = (num_blocks      ) & 0xFFU;
    this->data_buf[ 8] =    0;
    this->data_buf[ 9] =    0;
    this->data_buf[10] = (this->sector_size >> 8) & 0xFFU;
    this->data_buf[11] = (this->sector_size     ) & 0xFFU;

    this->data_buf[12] = page_code;

    switch (page_code) {
    case 0x01:
        this->data_buf[13] = 6; // data size
        std::memset(&this->data_buf[14], 0, 6);
        this->data_buf[0] += 7;
        break;
    case 0x30:
        this->data_buf[13] = 22; // data size
        std::memcpy(&this->data_buf[14], Apple_Copyright_Page_Data, 22);
        this->data_buf[0] += 23;
        break;
    default:
        ABORT_F("SCSI-HD: unsupported page %d in MODE_SENSE_6", page_code);
    }

    this->bytes_out = this->data_buf[0];
    this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;

    this->switch_phase(ScsiPhase::DATA_IN);
}

void ScsiCdrom::read_toc()
{
    int         tot_tracks;
    uint8_t     start_track = this->cmd_buf[6];
    uint16_t    alloc_len   = (this->cmd_buf[7] << 8) + this->cmd_buf[8];
    bool        is_msf      = !!(this->cmd_buf[1] & 2);

    if (this->cmd_buf[2] & 0xF) {
        ABORT_F("SCSI-CDROM: unsupported format in READ_TOC");
    }

    if (!alloc_len) {
        LOG_F(WARNING, "SCSI-CDROM: zero allocation length passed to READ_TOC");
        return;
    }

    if (!start_track) { // special case: track zero (lead-in) as starting track
        // return all tracks starting with track 1 plus lead-out
        start_track = 1;
        tot_tracks  = this->num_tracks + 1;
    } else if (start_track == LEAD_OUT_TRK_NUM) {
        start_track = this->num_tracks + 1;
        tot_tracks  = 1;
    } else if (start_track <= this->num_tracks) {
        tot_tracks  = (this->num_tracks - start_track) + 2;
    } else {
        LOG_F(ERROR, "SCSI-CDROM: invalid starting track %d in READ_TOC", start_track);
        this->status = ScsiStatus::CHECK_CONDITION;
        this->sense  = ScsiSense::ILLEGAL_REQ;
    }

    char* buf_ptr = this->data_buf;

    int data_len = (tot_tracks * 8) + 2;

    // write TOC data header
    *buf_ptr++ = (data_len >> 8) & 0xFFU;
    *buf_ptr++ = (data_len >> 0) & 0xFFU;
    *buf_ptr++ = 1; // 1st track number
    *buf_ptr++ = this->num_tracks; // last track number

    for (int tx = 0; tx < tot_tracks; tx++) {
        if ((buf_ptr - this->data_buf + 8) > alloc_len)
            break; // exit the loop if the output buffer length is exhausted

        TrackDescriptor& td = this->tracks[start_track + tx - 1];

        *buf_ptr++ = 0; // reserved
        *buf_ptr++ = td.adr_ctrl;
        *buf_ptr++ = td.trk_num;
        *buf_ptr++ = 0; // reserved

        if (is_msf) {
            AddrMsf msf = lba_to_msf(td.start_lba + 150);
            *buf_ptr++ = 0; // reserved
            *buf_ptr++ = msf.min;
            *buf_ptr++ = msf.sec;
            *buf_ptr++ = msf.frm;
        } else {
            *buf_ptr++ = (td.start_lba >> 24) & 0xFFU;
            *buf_ptr++ = (td.start_lba >> 16) & 0xFFU;
            *buf_ptr++ = (td.start_lba >>  8) & 0xFFU;
            *buf_ptr++ = (td.start_lba >>  0) & 0xFFU;
        }
    }

    this->bytes_out = alloc_len;
    this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;

    this->switch_phase(ScsiPhase::DATA_IN);
}

AddrMsf ScsiCdrom::lba_to_msf(const int lba)
{
    return {.min = lba / 4500, .sec = (lba / 75) % 60, .frm = lba % 75};
}

static const PropMap ScsiCdromProperties = {
    {"cdr_img", new StrProperty("")},
};

static const DeviceDescription ScsiCdromDescriptor =
    {ScsiCdrom::create, {}, ScsiCdromProperties};

REGISTER_DEVICE(ScsiCdrom, ScsiCdromDescriptor);