CassettePlayer.cc

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// TODO:
// - improve consistency when a reset occurs: tape is removed when you were
//   recording, but it is not removed when you were playing
// - specify prefix for auto file name generation when recording (setting?)
// - append to existing wav files when recording (record command), but this is
//   basically a special case (pointer at the end) of:
// - (partly) overwrite an existing wav file from any given time index
// - seek in cassette images for the next and previous file (using empty space?)
// - (partly) overwrite existing wav files with new tape data (not very hi prio)
// - handle read-only cassette images (e.g.: CAS images or WAV files with a RO
//   flag): refuse to go to record mode when those are selected
// - smartly auto-set the position of tapes: if you insert an existing WAV
//   file, it will have the position at the start, assuming PLAY mode by
//   default.  When specifying record mode at insert (somehow), it should be
//   at the back.
//   Alternatively, we could remember the index in tape images by storing the
//   index in some persistent data file with its SHA1 sum as it was as we last
//   saw it. When there are write actions to the tape, the hash has to be
//   recalculated and replaced in the data file. An optimization would be to
//   first simply check on the length of the file and fall back to SHA1 if that
//   results in multiple matches.
 
#include "CassettePlayer.hh"
#include "Connector.hh"
#include "CassettePort.hh"
#include "CommandController.hh"
#include "DeviceConfig.hh"
#include "HardwareConfig.hh"
#include "XMLElement.hh"
#include "FileContext.hh"
#include "FilePool.hh"
#include "File.hh"
#include "ReverseManager.hh"
#include "WavImage.hh"
#include "CasImage.hh"
#include "MSXCliComm.hh"
#include "MSXMotherBoard.hh"
#include "Reactor.hh"
#include "GlobalSettings.hh"
#include "CommandException.hh"
#include "EventDistributor.hh"
#include "FileOperations.hh"
#include "WavWriter.hh"
#include "TclObject.hh"
#include "DynamicClock.hh"
#include "EmuDuration.hh"
#include "checked_cast.hh"
#include "narrow.hh"
#include "serialize.hh"
#include "unreachable.hh"
#include "xrange.hh"
#include <algorithm>
#include <cassert>
#include <memory>
 
using std::string;
 
namespace openmsx {
 
// TODO: this description is not entirely accurate, but it is used
// as an identifier for this audio device in e.g. Catapult. We should
// use another way to identify audio devices A.S.A.P.!
static constexpr static_string_view DESCRIPTION = "Cassetteplayer, use to read .cas or .wav files.";
 
static constexpr unsigned DUMMY_INPUT_RATE = 44100; // actual rate depends on .cas/.wav file
static constexpr unsigned RECORD_FREQ = 44100;
static constexpr double RECIP_RECORD_FREQ = 1.0 / RECORD_FREQ;
static constexpr double OUTPUT_AMP = 60.0;
 
static std::string_view getCassettePlayerName()
{
        return "cassetteplayer";
}
 
CassettePlayer::CassettePlayer(const HardwareConfig& hwConf)
        : ResampledSoundDevice(hwConf.getMotherBoard(), getCassettePlayerName(), DESCRIPTION, 1, DUMMY_INPUT_RATE, false)
        , syncEndOfTape(hwConf.getMotherBoard().getScheduler())
        , syncAudioEmu (hwConf.getMotherBoard().getScheduler())
        , motherBoard(hwConf.getMotherBoard())
        , tapeCommand(
                motherBoard.getCommandController(),
                motherBoard.getStateChangeDistributor(),
                motherBoard.getScheduler())
        , loadingIndicator(
                motherBoard.getReactor().getGlobalSettings().getThrottleManager())
        , autoRunSetting(
                motherBoard.getCommandController(),
                "autoruncassettes", "automatically try to run cassettes", true)
{
        static const XMLElement* xml = [] {
                auto& doc = XMLDocument::getStaticDocument();
                XMLElement* result = doc.allocateElement("cassetteplayer");
                result->setFirstChild(doc.allocateElement("sound"))
                      ->setFirstChild(doc.allocateElement("volume", "5000"));
                return result;
        }();
        registerSound(DeviceConfig(hwConf, *xml));
 
        motherBoard.getReactor().getEventDistributor().registerEventListener(
                EventType::BOOT, *this);
        motherBoard.registerMediaInfo(getCassettePlayerName(), *this);
        motherBoard.getMSXCliComm().update(CliComm::UpdateType::HARDWARE, getCassettePlayerName(), "add");
 
        removeTape(EmuTime::zero());
}
 
CassettePlayer::~CassettePlayer()
{
        unregisterSound();
        if (auto* c = getConnector()) {
                c->unplug(getCurrentTime());
        }
        motherBoard.getReactor().getEventDistributor().unregisterEventListener(
                EventType::BOOT, *this);
        motherBoard.unregisterMediaInfo(*this);
        motherBoard.getMSXCliComm().update(CliComm::UpdateType::HARDWARE, getCassettePlayerName(), "remove");
}
 
void CassettePlayer::getMediaInfo(TclObject& result)
{
        result.addDictKeyValues("target", getImageName().getResolved(),
                                "state", getStateString(),
                                "position", getTapePos(getCurrentTime()),
                                "length", getTapeLength(getCurrentTime()),
                                "motorcontrol", motorControl);
}
 
void CassettePlayer::autoRun()
{
        if (!playImage) return;
        if (motherBoard.getReverseManager().isReplaying()) {
                // Don't execute the loading commands (keyboard type commands)
                // when we're replaying a recording. Because the recording
                // already contains those commands.
                return;
        }
 
        // try to automatically run the tape, if that's set
        CassetteImage::FileType type = playImage->getFirstFileType();
        if (!autoRunSetting.getBoolean() || type == CassetteImage::UNKNOWN) {
                return;
        }
        bool is_SVI = motherBoard.getMachineType() == "SVI"; // assume all other are 'MSX*' (might not be correct for 'Coleco')
        string H_READ = is_SVI ? "0xFE8E" : "0xFF07"; // Hook for Ready
        string H_MAIN = is_SVI ? "0xFE94" : "0xFF0C"; // Hook for Main Loop
        string instr1, instr2;
        switch (type) {
                case CassetteImage::ASCII:
                        instr1 = R"({RUN\"CAS:\"\r})";
                        break;
                case CassetteImage::BINARY:
                        instr1 = R"({BLOAD\"CAS:\",R\r})";
                        break;
                case CassetteImage::BASIC:
                        // Note that CLOAD:RUN won't work: BASIC ignores stuff
                        // after the CLOAD command. That's why it's split in two.
                        instr1 = "{CLOAD\\r}";
                        instr2 = "{RUN\\r}";
                        break;
                default:
                        UNREACHABLE; // Shouldn't be possible
        }
        string command = strCat(
                "namespace eval ::openmsx {\n"
                "  variable auto_run_bp\n"
 
                "  proc auto_run_cb {args} {\n"
                "    variable auto_run_bp\n"
                "    debug remove_bp $auto_run_bp\n"
                "    unset auto_run_bp\n"
 
                // Without the 0.2s delay here, the type command gets messed up
                // on MSX1 machines for some reason (starting to type too early?)
                // When using 0.1s delay only, the typing works, but still some
                // things go wrong on some machines with some games (see #1509
                // for instance)
                "    after time 0.2 \"type [lindex $args 0]\"\n"
 
                "    set next [lrange $args 1 end]\n"
                "    if {[llength $next] == 0} return\n"
 
                // H_READ is used by some firmwares; we need to hook the
                // H_MAIN that happens immediately after H_READ.
                "    set cmd \"openmsx::auto_run_cb $next\"\n"
                "    set openmsx::auto_run_bp [debug set_bp ", H_MAIN, " 1 \"$cmd\"]\n"
                "  }\n"
 
                "  if {[info exists auto_run_bp]} {debug remove_bp $auto_run_bp\n}\n"
                "  set auto_run_bp [debug set_bp ", H_READ, " 1 {\n"
                "    openmsx::auto_run_cb {{}} ", instr1, ' ', instr2, "\n"
                "  }]\n"
 
                // re-trigger hook(s), needed when already booted in BASIC
                "  type_via_keyboard \'\\r\n"
                "}");
        try {
                motherBoard.getCommandController().executeCommand(command);
        } catch (CommandException& e) {
                motherBoard.getMSXCliComm().printWarning(
                        "Error executing loading instruction using command \"",
                        command, "\" for AutoRun: ",
                        e.getMessage(), "\n Please report a bug.");
        }
}
 
string CassettePlayer::getStateString() const
{
        switch (getState()) {
                case PLAY:   return "play";
                case RECORD: return "record";
                case STOP:   return "stop";
        }
        UNREACHABLE;
}
 
bool CassettePlayer::isRolling() const
{
        // Is the tape 'rolling'?
        // is true when:
        //  not in stop mode (there is a tape inserted and not at end-of-tape)
        //  AND [ user forced playing (motorControl=off) OR motor enabled by
        //        software (motor=on) ]
        return (getState() != STOP) && (motor || !motorControl);
}
 
double CassettePlayer::getTapePos(EmuTime::param time)
{
        sync(time);
        if (getState() == RECORD) {
                // we record 8-bit mono, so bytes == samples
                return (double(recordImage->getBytes()) + partialInterval) * RECIP_RECORD_FREQ;
        } else {
                return (tapePos - EmuTime::zero()).toDouble();
        }
}
 
double CassettePlayer::getTapeLength(EmuTime::param time)
{
        if (playImage) {
                return (playImage->getEndTime() - EmuTime::zero()).toDouble();
        } else if (getState() == RECORD) {
                return getTapePos(time);
        } else {
                return 0.0;
        }
}
 
void CassettePlayer::checkInvariants() const
{
        switch (getState()) {
        case STOP:
                assert(!recordImage);
                if (playImage) {
                        // we're at end-of tape
                        assert(!getImageName().empty());
                } else {
                        // no tape inserted, imageName may or may not be empty
                }
                break;
        case PLAY:
                assert(!getImageName().empty());
                assert(!recordImage);
                assert(playImage);
                break;
        case RECORD:
                assert(!getImageName().empty());
                assert(recordImage);
                assert(!playImage);
                break;
        default:
                UNREACHABLE;
        }
}
 
void CassettePlayer::setState(State newState, const Filename& newImage,
                              EmuTime::param time)
{
        sync(time);
 
        // set new state if different from old state
        State oldState = getState();
        if (oldState == newState) return;
 
        // cannot directly switch from PLAY to RECORD or vice-versa,
        // (should always go via STOP)
        assert(!((oldState == PLAY)   && (newState == RECORD)));
        assert(!((oldState == RECORD) && (newState == PLAY)));
 
        // stuff for leaving the old state
        //  'recordImage==nullptr' can happen in case of loadstate.
        if ((oldState == RECORD) && recordImage) {
                flushOutput();
                bool empty = recordImage->isEmpty();
                recordImage.reset();
                if (empty) {
                        // delete the created WAV file, as it is useless
                        FileOperations::unlink(getImageName().getResolved()); // ignore errors
                        setImageName(Filename());
                }
        }
 
        // actually switch state
        state = newState;
        setImageName(newImage);
 
        // stuff for entering the new state
        if (newState == RECORD) {
                partialOut = 0.0;
                partialInterval = 0.0;
                lastX = lastOutput ? OUTPUT_AMP : -OUTPUT_AMP;
                lastY = 0.0;
        }
        motherBoard.getMSXCliComm().update(
                CliComm::UpdateType::STATUS, "cassetteplayer", getStateString());
 
        updateLoadingState(time); // sets SP for tape-end detection
 
        checkInvariants();
}
 
void CassettePlayer::updateLoadingState(EmuTime::param time)
{
        assert(prevSyncTime == time); // sync() must be called
        // TODO also set loadingIndicator for RECORD?
        // note: we don't use isRolling()
        loadingIndicator.update(motor && (getState() == PLAY));
 
        syncEndOfTape.removeSyncPoint();
        if (isRolling() && (getState() == PLAY)) {
                syncEndOfTape.setSyncPoint(time + (playImage->getEndTime() - tapePos));
        }
}
 
void CassettePlayer::setImageName(const Filename& newImage)
{
        casImage = newImage;
        motherBoard.getMSXCliComm().update(
                CliComm::UpdateType::MEDIA, "cassetteplayer", casImage.getResolved());
}
 
void CassettePlayer::insertTape(const Filename& filename, EmuTime::param time)
{
        if (!filename.empty()) {
                FilePool& filePool = motherBoard.getReactor().getFilePool();
                try {
                        // first try WAV
                        playImage = std::make_unique<WavImage>(filename, filePool);
                } catch (MSXException& e) {
                        try {
                                // if that fails use CAS
                                playImage = std::make_unique<CasImage>(
                                        filename, filePool,
                                        motherBoard.getMSXCliComm());
                        } catch (MSXException& e2) {
                                throw MSXException(
                                        "Failed to insert WAV image: \"",
                                        e.getMessage(),
                                        "\" and also failed to insert CAS image: \"",
                                        e2.getMessage(), '\"');
                        }
                }
        } else {
                // This is a bit tricky, consider this scenario: we switch from
                // RECORD->PLAY, but we didn't actually record anything: The
                // removeTape() call above (indirectly) deletes the empty
                // recorded wav image and also clears imageName. Now because
                // the 'filename' parameter is passed by reference, and because
                // getImageName() returns a reference, this 'filename'
                // parameter now also is an empty string.
        }
 
        // possibly recreate resampler
        if (unsigned inputRate = playImage ? playImage->getFrequency() : 44100;
            inputRate != getInputRate()) {
                setInputRate(inputRate);
                createResampler();
        }
 
        // trigger (re-)query of getAmplificationFactorImpl()
        setSoftwareVolume(1.0f, time);
 
        setImageName(filename);
}
 
void CassettePlayer::playTape(const Filename& filename, EmuTime::param time)
{
        // Temporally go to STOP state:
        // RECORD: First close the recorded image. Otherwise it goes wrong
        //         if you switch from RECORD->PLAY on the same image.
        // PLAY: Go to stop because we temporally violate some invariants
        //       (tapePos can be beyond end-of-tape).
        setState(STOP, getImageName(), time); // keep current image
        insertTape(filename, time);
        rewind(time); // sets PLAY mode
        autoRun();
}
 
void CassettePlayer::rewind(EmuTime::param time)
{
        sync(time); // before tapePos changes
        assert(getState() != RECORD);
        tapePos = EmuTime::zero();
        audioPos = 0;
 
        if (getImageName().empty()) {
                // no image inserted, do nothing
                assert(getState() == STOP);
        } else {
                // keep current image
                setState(PLAY, getImageName(), time);
        }
        updateLoadingState(time);
}
 
void CassettePlayer::recordTape(const Filename& filename, EmuTime::param time)
{
        removeTape(time); // flush (possible) previous recording
        recordImage = std::make_unique<Wav8Writer>(filename, 1, RECORD_FREQ);
        tapePos = EmuTime::zero();
        setState(RECORD, filename, time);
}
 
void CassettePlayer::removeTape(EmuTime::param time)
{
        // first stop with tape still inserted
        setState(STOP, getImageName(), time);
        // then remove the tape
        playImage.reset();
        tapePos = EmuTime::zero();
        setImageName({});
}
 
void CassettePlayer::setMotor(bool status, EmuTime::param time)
{
        if (status != motor) {
                sync(time);
                motor = status;
                updateLoadingState(time);
        }
}
 
void CassettePlayer::setMotorControl(bool status, EmuTime::param time)
{
        if (status != motorControl) {
                sync(time);
                motorControl = status;
                updateLoadingState(time);
        }
}
 
int16_t CassettePlayer::readSample(EmuTime::param time)
{
        if (getState() == PLAY) {
                // playing
                sync(time);
                return isRolling() ? playImage->getSampleAt(tapePos) : int16_t(0);
        } else {
                // record or stop
                return 0;
        }
}
 
void CassettePlayer::setSignal(bool output, EmuTime::param time)
{
        sync(time);
        lastOutput = output;
}
 
void CassettePlayer::sync(EmuTime::param time)
{
        EmuDuration duration = time - prevSyncTime;
        prevSyncTime = time;
 
        updateTapePosition(duration, time);
        generateRecordOutput(duration);
}
 
void CassettePlayer::updateTapePosition(
        EmuDuration::param duration, EmuTime::param time)
{
        if (!isRolling() || (getState() != PLAY)) return;
 
        tapePos += duration;
        assert(tapePos <= playImage->getEndTime());
 
        // synchronize audio with actual tape position
        if (!syncScheduled) {
                // don't sync too often, this improves sound quality
                syncScheduled = true;
                syncAudioEmu.setSyncPoint(time + EmuDuration::sec(1));
        }
}
 
void CassettePlayer::generateRecordOutput(EmuDuration::param duration)
{
        if (!recordImage || !isRolling()) return;
 
        double out = lastOutput ? OUTPUT_AMP : -OUTPUT_AMP;
        double samples = duration.toDouble() * RECORD_FREQ;
        if (auto rest = 1.0 - partialInterval; rest <= samples) {
                // enough to fill next interval
                partialOut += out * rest;
                fillBuf(1, partialOut);
                samples -= rest;
 
                // fill complete intervals
                auto count = int(samples);
                if (count > 0) {
                        fillBuf(count, out);
                }
                samples -= count;
                assert(samples < 1.0);
 
                // partial last interval
                partialOut = samples * out;
                partialInterval = samples;
        } else {
                assert(samples < 1.0);
                partialOut += samples * out;
                partialInterval += samples;
        }
        assert(partialInterval < 1.0);
}
 
void CassettePlayer::fillBuf(size_t length, double x)
{
        assert(recordImage);
        static constexpr double A = 252.0 / 256.0;
 
        double y = lastY + (x - lastX);
 
        while (length) {
                size_t len = std::min(length, buf.size() - sampCnt);
                repeat(len, [&] {
                        buf[sampCnt++] = narrow<uint8_t>(int(y) + 128);
                        y *= A;
                });
                length -= len;
                assert(sampCnt <= buf.size());
                if (sampCnt == buf.size()) {
                        flushOutput();
                }
        }
        lastY = y;
        lastX = x;
}
 
void CassettePlayer::flushOutput()
{
        try {
                recordImage->write(subspan(buf, 0, sampCnt));
                sampCnt = 0;
                recordImage->flush(); // update wav header
        } catch (MSXException& e) {
                motherBoard.getMSXCliComm().printWarning(
                        "Failed to write to tape: ", e.getMessage());
        }
}
 
 
std::string_view CassettePlayer::getName() const
{
        return getCassettePlayerName();
}
 
std::string_view CassettePlayer::getDescription() const
{
        return DESCRIPTION;
}
 
void CassettePlayer::plugHelper(Connector& conn, EmuTime::param time)
{
        sync(time);
        lastOutput = checked_cast<CassettePort&>(conn).lastOut();
}
 
void CassettePlayer::unplugHelper(EmuTime::param time)
{
        // note: may not throw exceptions
        setState(STOP, getImageName(), time); // keep current image
}
 
 
void CassettePlayer::generateChannels(std::span<float*> buffers, unsigned num)
{
        // Single channel device: replace content of buffers[0] (not add to it).
        assert(buffers.size() == 1);
        if ((getState() != PLAY) || !isRolling()) {
                buffers[0] = nullptr;
                return;
        }
        assert(buffers.size() == 1);
        playImage->fillBuffer(audioPos, buffers.first<1>(), num);
        audioPos += num;
}
 
float CassettePlayer::getAmplificationFactorImpl() const
{
        return playImage ? playImage->getAmplificationFactorImpl() : 1.0f;
}
 
bool CassettePlayer::signalEvent(const Event& event)
{
        if (getType(event) == EventType::BOOT && !getImageName().empty()) {
                // Reinsert tape to make sure everything is reset.
                try {
                        playTape(getImageName(), getCurrentTime());
                } catch (MSXException& e) {
                        motherBoard.getMSXCliComm().printWarning(
                                "Failed to insert tape: ", e.getMessage());
                }
        }
        return false;
}
 
void CassettePlayer::execEndOfTape(EmuTime::param time)
{
        // tape ended
        sync(time);
        assert(tapePos == playImage->getEndTime());
        motherBoard.getMSXCliComm().printWarning(
                "Tape end reached... stopping. "
                "You may need to insert another tape image "
                "that contains side B. (Or you used the wrong "
                "loading command.)");
        setState(STOP, getImageName(), time); // keep current image
}
 
void CassettePlayer::execSyncAudioEmu(EmuTime::param time)
{
        if (getState() == PLAY) {
                updateStream(time);
                sync(time);
                DynamicClock clk(EmuTime::zero());
                clk.setFreq(playImage->getFrequency());
                audioPos = clk.getTicksTill(tapePos);
        }
        syncScheduled = false;
}
 
 
// class TapeCommand
 
CassettePlayer::TapeCommand::TapeCommand(
                CommandController& commandController_,
                StateChangeDistributor& stateChangeDistributor_,
                Scheduler& scheduler_)
        : RecordedCommand(commandController_, stateChangeDistributor_,
                          scheduler_, "cassetteplayer")
{
}
 
void CassettePlayer::TapeCommand::execute(
        std::span<const TclObject> tokens, TclObject& result, EmuTime::param time)
{
        auto& cassettePlayer = OUTER(CassettePlayer, tapeCommand);
        if (tokens.size() == 1) {
                // Returning Tcl lists here, similar to the disk commands in
                // DiskChanger
                TclObject options = makeTclList(cassettePlayer.getStateString());
                result.addListElement(tmpStrCat(getName(), ':'),
                                      cassettePlayer.getImageName().getResolved(),
                                      options);
 
        } else if (tokens[1] == "new") {
                std::string_view prefix = "openmsx";
                string filename = FileOperations::parseCommandFileArgument(
                        (tokens.size() == 3) ? tokens[2].getString() : string{},
                        TAPE_RECORDING_DIR, prefix, TAPE_RECORDING_EXTENSION);
                cassettePlayer.recordTape(Filename(filename), time);
                result = tmpStrCat(
                        "Created new cassette image file: ", filename,
                        ", inserted it and set recording mode.");
 
        } else if (tokens[1] == "insert" && tokens.size() == 3) {
                try {
                        result = "Changing tape";
                        Filename filename(tokens[2].getString(), userFileContext());
                        cassettePlayer.playTape(filename, time);
                } catch (MSXException& e) {
                        throw CommandException(std::move(e).getMessage());
                }
 
        } else if (tokens[1] == "motorcontrol" && tokens.size() == 3) {
                if (tokens[2] == "on") {
                        cassettePlayer.setMotorControl(true, time);
                        result = "Motor control enabled.";
                } else if (tokens[2] == "off") {
                        cassettePlayer.setMotorControl(false, time);
                        result = "Motor control disabled.";
                } else {
                        throw SyntaxError();
                }
 
        } else if (tokens.size() != 2) {
                throw SyntaxError();
 
        } else if (tokens[1] == "motorcontrol") {
                result = tmpStrCat("Motor control is ",
                                (cassettePlayer.motorControl ? "on" : "off"));
 
        } else if (tokens[1] == "record") {
                        result = "TODO: implement this... (sorry)";
 
        } else if (tokens[1] == "play") {
                if (cassettePlayer.getState() == CassettePlayer::RECORD) {
                        try {
                                result = "Play mode set, rewinding tape.";
                                cassettePlayer.playTape(
                                        cassettePlayer.getImageName(), time);
                        } catch (MSXException& e) {
                                throw CommandException(std::move(e).getMessage());
                        }
                } else if (cassettePlayer.getState() == CassettePlayer::STOP) {
                        throw CommandException("No tape inserted or tape at end!");
                } else {
                        // PLAY mode
                        result = "Already in play mode.";
                }
 
        } else if (tokens[1] == "eject") {
                result = "Tape ejected";
                cassettePlayer.removeTape(time);
 
        } else if (tokens[1] == "rewind") {
                string r;
                if (cassettePlayer.getState() == CassettePlayer::RECORD) {
                        try {
                                r = "First stopping recording... ";
                                cassettePlayer.playTape(
                                        cassettePlayer.getImageName(), time);
                        } catch (MSXException& e) {
                                throw CommandException(std::move(e).getMessage());
                        }
                }
                cassettePlayer.rewind(time);
                r += "Tape rewound";
                result = r;
 
        } else if (tokens[1] == "getpos") {
                result = cassettePlayer.getTapePos(time);
 
        } else if (tokens[1] == "getlength") {
                result = cassettePlayer.getTapeLength(time);
 
        } else {
                try {
                        result = "Changing tape";
                        Filename filename(tokens[1].getString(), userFileContext());
                        cassettePlayer.playTape(filename, time);
                } catch (MSXException& e) {
                        throw CommandException(std::move(e).getMessage());
                }
        }
        //if (!cassettePlayer.getConnector()) {
        //      cassettePlayer.cliComm.printWarning("Cassette player not plugged in.");
        //}
}
 
string CassettePlayer::TapeCommand::help(std::span<const TclObject> tokens) const
{
        string helpText;
        if (tokens.size() >= 2) {
                if (tokens[1] == "eject") {
                        helpText =
                            "Well, just eject the cassette from the cassette "
                            "player/recorder!";
                } else if (tokens[1] == "rewind") {
                        helpText =
                            "Indeed, rewind the tape that is currently in the "
                            "cassette player/recorder...";
                } else if (tokens[1] == "motorcontrol") {
                        helpText =
                            "Setting this to 'off' is equivalent to "
                            "disconnecting the black remote plug from the "
                            "cassette player: it makes the cassette player "
                            "run (if in play mode); the motor signal from the "
                            "MSX will be ignored. Normally this is set to "
                            "'on': the cassetteplayer obeys the motor control "
                            "signal from the MSX.";
                } else if (tokens[1] == "play") {
                        helpText =
                            "Go to play mode. Only useful if you were in "
                            "record mode (which is currently the only other "
                            "mode available).";
                } else if (tokens[1] == "new") {
                        helpText =
                            "Create a new cassette image. If the file name is "
                            "omitted, one will be generated in the default "
                            "directory for tape recordings. Implies going to "
                            "record mode (why else do you want a new cassette "
                            "image?).";
                } else if (tokens[1] == "insert") {
                        helpText =
                            "Inserts the specified cassette image into the "
                            "cassette player, rewinds it and switches to play "
                            "mode.";
                } else if (tokens[1] == "record") {
                        helpText =
                            "Go to record mode. NOT IMPLEMENTED YET. Will be "
                            "used to be able to resume recording to an "
                            "existing cassette image, previously inserted with "
                            "the insert command.";
                } else if (tokens[1] == "getpos") {
                        helpText =
                            "Return the position of the tape, in seconds from "
                            "the beginning of the tape.";
                } else if (tokens[1] == "getlength") {
                        helpText =
                            "Return the length of the tape in seconds.";
                }
        } else {
                helpText =
                    "cassetteplayer eject             "
                    ": remove tape from virtual player\n"
                    "cassetteplayer rewind            "
                    ": rewind tape in virtual player\n"
                    "cassetteplayer motorcontrol      "
                    ": enables or disables motor control (remote)\n"
                    "cassetteplayer play              "
                    ": change to play mode (default)\n"
                    "cassetteplayer record            "
                    ": change to record mode (NOT IMPLEMENTED YET)\n"
                    "cassetteplayer new [<filename>]  "
                    ": create and insert new tape image file and go to record mode\n"
                    "cassetteplayer insert <filename> "
                    ": insert (a different) tape file\n"
                    "cassetteplayer getpos            "
                    ": query the position of the tape\n"
                    "cassetteplayer getlength         "
                    ": query the total length of the tape\n"
                    "cassetteplayer <filename>        "
                    ": insert (a different) tape file\n";
        }
        return helpText;
}
 
void CassettePlayer::TapeCommand::tabCompletion(std::vector<string>& tokens) const
{
        using namespace std::literals;
        if (tokens.size() == 2) {
                static constexpr std::array cmds = {
                        "eject"sv, "rewind"sv, "motorcontrol"sv, "insert"sv, "new"sv,
                        "play"sv, "getpos"sv, "getlength"sv,
                        //"record"sv,
                };
                completeFileName(tokens, userFileContext(), cmds);
        } else if ((tokens.size() == 3) && (tokens[1] == "insert")) {
                completeFileName(tokens, userFileContext());
        } else if ((tokens.size() == 3) && (tokens[1] == "motorcontrol")) {
                static constexpr std::array extra = {"on"sv, "off"sv};
                completeString(tokens, extra);
        }
}
 
bool CassettePlayer::TapeCommand::needRecord(std::span<const TclObject> tokens) const
{
        return tokens.size() > 1;
}
 
 
static constexpr std::initializer_list<enum_string<CassettePlayer::State>> stateInfo = {
        { "PLAY",   CassettePlayer::PLAY   },
        { "RECORD", CassettePlayer::RECORD },
        { "STOP",   CassettePlayer::STOP   }
};
SERIALIZE_ENUM(CassettePlayer::State, stateInfo);
 
// version 1: initial version
// version 2: added checksum
template<typename Archive>
void CassettePlayer::serialize(Archive& ar, unsigned version)
{
        if (recordImage) {
                // buf, sampCnt
                flushOutput();
        }
 
        ar.serialize("casImage", casImage);
 
        Sha1Sum oldChecksum;
        if constexpr (!Archive::IS_LOADER) {
                if (playImage) {
                        oldChecksum = playImage->getSha1Sum();
                }
        }
        if (ar.versionAtLeast(version, 2)) {
                string oldChecksumStr = oldChecksum.empty()
                                      ? string{}
                                      : oldChecksum.toString();
                ar.serialize("checksum", oldChecksumStr);
                oldChecksum = oldChecksumStr.empty()
                            ? Sha1Sum()
                            : Sha1Sum(oldChecksumStr);
        }
 
        if constexpr (Archive::IS_LOADER) {
                FilePool& filePool = motherBoard.getReactor().getFilePool();
                auto time = getCurrentTime();
                casImage.updateAfterLoadState();
                if (!oldChecksum.empty() &&
                    !FileOperations::exists(casImage.getResolved())) {
                        auto file = filePool.getFile(FileType::TAPE, oldChecksum);
                        if (file.is_open()) {
                                casImage.setResolved(file.getURL());
                        }
                }
                try {
                        insertTape(casImage, time);
                } catch (MSXException&) {
                        if (oldChecksum.empty()) {
                                // It's OK if we cannot reinsert an empty
                                // image. One likely scenario for this case is
                                // the following:
                                //  - cassetteplayer new myfile.wav
                                //  - don't actually start saving to tape yet
                                //  - create a savestate and load that state
                                // Because myfile.wav contains no data yet, it
                                // is deleted from the filesystem. So on a
                                // loadstate it won't be found.
                        } else {
                                throw;
                        }
                }
 
                if (playImage && !oldChecksum.empty()) {
                        Sha1Sum newChecksum = playImage->getSha1Sum();
                        if (oldChecksum != newChecksum) {
                                motherBoard.getMSXCliComm().printWarning(
                                        "The content of the tape ",
                                        casImage.getResolved(),
                                        " has changed since the time this "
                                        "savestate was created. This might "
                                        "result in emulation problems.");
                        }
                }
        }
 
        // only for RECORD
        //double lastX;
        //double lastY;
        //double partialOut;
        //double partialInterval;
        //std::unique_ptr<WavWriter> recordImage;
 
        ar.serialize("tapePos",      tapePos,
                     "prevSyncTime", prevSyncTime,
                     "audioPos",     audioPos,
                     "state",        state,
                     "lastOutput",   lastOutput,
                     "motor",        motor,
                     "motorControl", motorControl);
 
        if constexpr (Archive::IS_LOADER) {
                auto time = getCurrentTime();
                if (playImage && (tapePos > playImage->getEndTime())) {
                        tapePos = playImage->getEndTime();
                        motherBoard.getMSXCliComm().printWarning("Tape position "
                                "beyond tape end! Setting tape position to end. "
                                "This can happen if you load a replay from an "
                                "older openMSX version with a different CAS-to-WAV "
                                "baud rate or when the tape image has been changed "
                                "compared to when the replay was created.");
                }
                if (state == RECORD) {
                        // TODO we don't support savestates in RECORD mode yet
                        motherBoard.getMSXCliComm().printWarning(
                                "Restoring a state where the MSX was saving to "
                                "tape is not yet supported. Emulation will "
                                "continue without actually saving.");
                        setState(STOP, getImageName(), time);
                }
                if (!playImage && (state == PLAY)) {
                        // This should only happen for manually edited
                        // savestates, though we shouldn't crash on it.
                        setState(STOP, getImageName(), time);
                }
                sync(time);
                updateLoadingState(time);
        }
}
INSTANTIATE_SERIALIZE_METHODS(CassettePlayer);
REGISTER_POLYMORPHIC_INITIALIZER(Pluggable, CassettePlayer, "CassettePlayer");
 
} // namespace openmsx