#include "QGCUASFileManager.h"
#include "QGC.h"
#include "MAVLinkProtocol.h"

#include <QFile>
#include <QDir>
#include <string>

static const quint32 crctab[] =
{
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
    0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

QGCUASFileManager::QGCUASFileManager(QObject* parent, UASInterface* uas) :
    QObject(parent),
    _mav(uas),
    _encdata_seq(0)
{
}

quint32
QGCUASFileManager::crc32(const uint8_t *src, unsigned len, unsigned state)
{
    for (unsigned i = 0; i < len; i++)
        state = crctab[(state ^ src[i]) & 0xff] ^ (state >> 8);
    return state;
}

void QGCUASFileManager::nothingMessage()
{
    mavlink_message_t message;

    RequestHeader hdr;
    hdr.magic = 'f';
    hdr.session = 0;
    hdr.crc32 = 0;
    hdr.size = 0;
    hdr.crc32 = crc32((uint8_t*)&hdr, sizeof(hdr) + hdr.size, 0);

    mavlink_msg_encapsulated_data_pack(250, 0, &message, _encdata_seq, (uint8_t*)&hdr);

    _mav->sendMessage(message);
    qDebug() << "Sent message!";
}

void QGCUASFileManager::receiveMessage(LinkInterface* link, mavlink_message_t message)
{
    Q_UNUSED(link);

    if (message.msgid != MAVLINK_MSG_ID_ENCAPSULATED_DATA) {
        // wtf, not for us
        return;
    }

    mavlink_encapsulated_data_t data;
    mavlink_msg_encapsulated_data_decode(&message, &data);
    const RequestHeader *hdr = (const RequestHeader *)&data.data[0];

    // XXX VALIDATE MESSAGE

    switch (_current_operation) {
    case kCOIdle:
        // we should not be seeing anything here.. shut the other guy up
        qDebug() << "FTP resetting file transfer session";
        sendReset();
        break;

    case kCOList:
        if (hdr->opcode == kRspAck) {
            listDecode(&hdr->data[0], hdr->size);
        } else if (hdr->opcode == kRspNak) {
            emit statusMessage(QString("error: ").append(errorString(hdr->data[0])));
        }
        break;

    default:
        emit statusMessage("message in unexpected state");
    }
}

void QGCUASFileManager::listRecursively(const QString &from)
{
    if (_current_operation != kCOIdle) {
        // XXX beep and don't do anything
    }

    // clear the text widget
    emit resetStatusMessages();

    // initialise the lister
    _list_path = from;
    _list_offset = 0;
    _current_operation = kCOList;

    // and send the initial request
    sendList();
}

void QGCUASFileManager::listDecode(const uint8_t *data, unsigned len)
{
    unsigned offset = 0;
    unsigned files = 0;

    // parse filenames out of the buffer
    while (offset < len) {

        // get the length of the name
        unsigned nlen = strnlen((const char *)data + offset, len - offset);
        if (nlen < 2) {
            break;
        }

        QString s((const char *)data + offset + 1);
        if (data[0] == 'D') {
            s.append('/');
        }

        // put it in the view
        emit statusMessage(s);

        // account for the name + NUL
        offset += nlen + 1;

        // account for the file
        files++;
    }

    // we have run out of files to list
    if (files == 0) {
        _current_operation = kCOIdle;
    } else {
        // update our state
        _list_offset += files;

        // and send another request
        sendList();
    }
}

void QGCUASFileManager::sendReset()
{
    mavlink_message_t message;

    RequestHeader hdr;
    hdr.magic = 'f';
    hdr.session = 0;
    hdr.opcode = kCmdReset;
    hdr.crc32 = 0;
    hdr.offset = 0;
    hdr.size = 0;
    hdr.crc32 = crc32((uint8_t*)&hdr, sizeof(hdr) + hdr.size, 0);

    mavlink_msg_encapsulated_data_pack(250, 0, &message, _encdata_seq, (uint8_t*)&hdr); // XXX 250 is a magic length

    _mav->sendMessage(message);
}

void QGCUASFileManager::sendList()
{
    mavlink_message_t message;

    RequestHeader hdr;
    hdr.magic = 'f';
    hdr.session = 0;
    hdr.opcode = kCmdList;
    hdr.crc32 = 0;
    hdr.offset = _list_offset;
    strncpy((char *)&hdr.data[0], _list_path.toStdString().c_str(), 200); // XXX should have a real limit here
    hdr.size = strlen((const char *)&hdr.data[0]);

    hdr.crc32 = crc32((uint8_t*)&hdr, sizeof(hdr) + hdr.size, 0);

    mavlink_msg_encapsulated_data_pack(250, 0, &message, _encdata_seq, (uint8_t*)&hdr); // XXX 250 is a magic length

    _mav->sendMessage(message);
}

void QGCUASFileManager::downloadPath(const QString &from, const QString &to)
{
    Q_UNUSED(from);
    
    // Send path, e.g. /fs/microsd and download content
    // recursively into a local directory

    char buf[255];
    unsigned len = 10;

    QByteArray data(buf, len);
    QString filename = "log001.bin"; // XXX get this from onboard

    // Qt takes care of slash conversions in paths
    QFile file(to + QDir::separator() + filename);
    file.open(QIODevice::WriteOnly);
    file.write(data);
    file.close();

    emit statusMessage(QString("Downloaded: %1 to directory %2").arg(filename).arg(to));
}

QString QGCUASFileManager::errorString(uint8_t errorCode)
{
    switch(errorCode) {
    case kErrNone:
        return QString("no error");
    case kErrNoRequest:
        return QString("bad request");
    case kErrNoSession:
        return QString("bad session");
    case kErrSequence:
        return QString("bad sequence number");
    case kErrNotDir:
        return QString("not a directory");
    case kErrNotFile:
        return QString("not a file");
    case kErrEOF:
        return QString("read beyond end of file");
    case kErrNotAppend:
        return QString("write not at end of file");
    case kErrTooBig:
        return QString("file too big");
    case kErrIO:
        return QString("device I/O error");
    case kErrPerm:
        return QString("permission denied");
    default:
        return QString("bad error code");
    }
}