#include "deck_loader.h"

#include <QApplication>
#include <QClipboard>
#include <QDebug>
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QFutureWatcher>
#include <QPrinter>
#include <QRegularExpression>
#include <QSaveFile>
#include <QStringList>
#include <QTextCursor>
#include <QTextDocument>
#include <QTextStream>
#include <QTextTable>
#include <QtConcurrentRun>
#include <libcockatrice/card/database/card_database.h>
#include <libcockatrice/card/database/card_database_manager.h>
#include <libcockatrice/card/import/card_name_normalizer.h>
#include <libcockatrice/deck_list/deck_list.h>
#include <libcockatrice/deck_list/tree/deck_list_card_node.h>

const QStringList DeckLoader::ACCEPTED_FILE_EXTENSIONS = {"*.cod", "*.dec", "*.dek", "*.txt", "*.mwDeck"};

const QStringList DeckLoader::FILE_NAME_FILTERS = {
    tr("Common deck formats (%1)").arg(ACCEPTED_FILE_EXTENSIONS.join(" ")), tr("All files (*.*)")};

DeckLoader::DeckLoader(QObject *parent) : QObject(parent)
{
}

std::optional<LoadedDeck>
DeckLoader::loadFromFile(const QString &fileName, DeckFileFormat::Format fmt, bool userRequest)
{
    QFile file(fileName);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        qCWarning(DeckLoaderLog) << "File does not exist:" << fileName;
        return std::nullopt;
    }

    bool result = false;
    DeckList deckList;
    switch (fmt) {
        case DeckFileFormat::PlainText:
            result = deckList.loadFromFile_Plain(&file, CardNameNormalizer());
            break;
        case DeckFileFormat::Cockatrice: {
            result = deckList.loadFromFile_Native(&file);
            if (!result) {
                qCInfo(DeckLoaderLog) << "Failed to load " << fileName
                                      << "as cockatrice format; retrying as plain format";
                file.seek(0);
                result = deckList.loadFromFile_Plain(&file, CardNameNormalizer());
                fmt = DeckFileFormat::PlainText;
            }
            break;
        }

        default:
            break;
    }

    if (!result) {
        qCWarning(DeckLoaderLog) << "Failed to load " << fileName << "as" << fmt;
        return std::nullopt;
    }

    LoadedDeck::LoadInfo lastLoadInfo = {
        .fileName = fileName,
        .fileFormat = fmt,
    };
    LoadedDeck loadedDeck = {deckList, lastLoadInfo};

    if (userRequest) {
        updateLastLoadedTimestamp(loadedDeck);
    }

    qCDebug(DeckLoaderLog) << "Loaded deck" << fileName << "with userRequest:" << userRequest;

    return loadedDeck;
}

void DeckLoader::loadFromFileAsync(const QString &fileName, DeckFileFormat::Format fmt, bool userRequest)
{
    QFuture<void> future = QtConcurrent::run([=, this] {
        std::optional<LoadedDeck> deckOpt = loadFromFile(fileName, fmt, userRequest);
        if (deckOpt) {
            loadedDeck = deckOpt.value();
        }
        emit loadFinished(deckOpt.has_value());
    });
}

bool DeckLoader::reload()
{
    QString lastFileName = loadedDeck.lastLoadInfo.fileName;
    if (lastFileName.isEmpty()) {
        return false;
    }
    std::optional<LoadedDeck> deck = loadFromFile(lastFileName, loadedDeck.lastLoadInfo.fileFormat, false);

    if (!deck) {
        return false;
    }

    loadedDeck = *deck;
    return true;
}

std::optional<LoadedDeck> DeckLoader::loadFromRemote(const QString &nativeString, int remoteDeckId)
{
    DeckList deckList;
    bool success = deckList.loadFromString_Native(nativeString);

    if (!success) {
        qCWarning(DeckLoaderLog) << "Failed to load remote deck with id" << remoteDeckId << ":" << nativeString;
        return std::nullopt;
    }

    LoadedDeck::LoadInfo lastLoadInfo = {.remoteDeckId = remoteDeckId};
    LoadedDeck loadedDeck = {deckList, lastLoadInfo};

    qCDebug(DeckLoaderLog) << "Loaded remote deck with id" << remoteDeckId;

    return loadedDeck;
}

std::optional<LoadedDeck::LoadInfo>
DeckLoader::saveToFile(const DeckList &deck, const QString &fileName, DeckFileFormat::Format fmt)
{
    // Use QSaveFile so that a failed write (e.g. a full disk) leaves the existing deck untouched
    // instead of truncating it to a 0-byte file. The target is only replaced once every byte has
    // been flushed successfully in commit().
    QSaveFile file(fileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
        qCWarning(DeckLoaderLog) << "Could not create or open file:" << fileName;
        return std::nullopt;
    }

    bool success = false;
    switch (fmt) {
        case DeckFileFormat::PlainText:
            success = deck.saveToFile_Plain(&file);
            break;
        case DeckFileFormat::Cockatrice:
            success = deck.saveToFile_Native(&file);
            break;
    }

    if (!success) {
        file.cancelWriting();
        qCWarning(DeckLoaderLog) << "Failed to serialize deck for file:" << fileName;
        return std::nullopt;
    }

    if (!file.commit()) {
        qCWarning(DeckLoaderLog) << "Failed to save deck to " << fileName << ":" << file.errorString();
        return std::nullopt;
    }

    qCInfo(DeckLoaderLog) << "Saved deck to " << fileName << "with format" << fmt;

    LoadedDeck::LoadInfo lastLoadInfo = {fileName, fmt};
    return lastLoadInfo;
}

bool DeckLoader::saveToFile(const LoadedDeck &deck)
{
    auto opt = saveToFile(deck.deckList, deck.lastLoadInfo.fileName, deck.lastLoadInfo.fileFormat);
    return opt.has_value();
}

bool DeckLoader::saveToNewFile(LoadedDeck &deck, const QString &fileName, DeckFileFormat::Format fmt)
{
    std::optional<LoadedDeck::LoadInfo> infoOpt = saveToFile(deck.deckList, fileName, fmt);

    if (infoOpt) {
        deck.lastLoadInfo = infoOpt.value();
    }

    return infoOpt.has_value();
}

/**
 * @brief Updates the lastLoadedTimestamp field in the file corresponding to the deck, without changing the
 * FileModificationTime of the file.
 */
bool DeckLoader::updateLastLoadedTimestamp(LoadedDeck &deck)
{
    // text format doesn't support lastLoadedTimestamp, so there's no point in proceeding
    if (deck.lastLoadInfo.fileFormat != DeckFileFormat::Cockatrice) {
        return false;
    }

    QString fileName = deck.lastLoadInfo.fileName;

    QFileInfo fileInfo(fileName);
    if (!fileInfo.exists()) {
        qCWarning(DeckLoaderLog) << "File does not exist:" << fileName;
        return false;
    }

    QDateTime originalTimestamp = fileInfo.lastModified();

    // Use QSaveFile so that a failed write (e.g. a full disk) cannot truncate an existing deck to a
    // 0-byte file while merely bumping its timestamp.
    QSaveFile file(fileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
        qCWarning(DeckLoaderLog) << "Failed to open file for writing:" << fileName;
        return false;
    }

    // Perform file modifications
    deck.deckList.setLastLoadedTimestamp(QDateTime::currentDateTime().toString());

    if (!deck.deckList.saveToFile_Native(&file)) {
        file.cancelWriting();
        qCWarning(DeckLoaderLog) << "Failed to serialize deck for file:" << fileName;
        return false;
    }

    if (!file.commit()) {
        qCWarning(DeckLoaderLog) << "Failed to update timestamp for file:" << fileName << ":" << file.errorString();
        return false;
    }

    // Re-open the file and restore the original timestamp, so that updating the lastLoadedTimestamp
    // does not change the file's modification time.
    QFile timestampFile(fileName);
    if (!timestampFile.open(QIODevice::ReadWrite)) {
        qCWarning(DeckLoaderLog) << "Failed to re-open file to set timestamp:" << fileName;
        return false;
    }

    if (!timestampFile.setFileTime(originalTimestamp, QFileDevice::FileModificationTime)) {
        qCWarning(DeckLoaderLog) << "Failed to set modification time for file:" << fileName;
        timestampFile.close();
        return false;
    }

    timestampFile.close();
    return true;
}

static QString getDomainForWebsite(DeckLoader::DecklistWebsite website)
{
    switch (website) {
        case DeckLoader::DecklistOrg:
            return "www.decklist.org";
        case DeckLoader::DecklistXyz:
            return "www.decklist.xyz";
        default:
            qCWarning(DeckLoaderLog) << "Invalid decklist website enum:" << website;
            return "";
    }
}

/**
 * Converts the card to the String that represents it in the decklist export
 */
static QString toDecklistExportString(const DecklistCardNode *card)
{
    QString cardString;
    // Get the number of cards and add the card name
    cardString += QString::number(card->getNumber());
    // Add a space between card num and name
    cardString += "%20";
    // Add card name
    cardString += card->getName();

    if (!card->getCardSetShortName().isNull()) {
        cardString += "%20";
        cardString += "(" + card->getCardSetShortName() + ")";
    }
    if (!card->getCardCollectorNumber().isNull()) {
        cardString += "%20";
        cardString += card->getCardCollectorNumber();
    }

    // Add a return at the end of the card
    cardString += "%0A";

    return cardString;
}

/**
 * Converts all cards in the list to their decklist export string and joins them into one string
 */
static QString toDecklistExportString(const QList<const DecklistCardNode *> &cardNodes)
{
    QString result;

    for (auto cardNode : cardNodes) {
        result += toDecklistExportString(cardNode);
    }

    return result;
}

/**
 * Export deck to decklist function, called to format the deck in a way to be sent to a server
 *
 * @param deckList The decklist to export
 * @param website The website we're sending the deck to
 */
QString DeckLoader::exportDeckToDecklist(const DeckList &deckList, DecklistWebsite website)
{
    // Add the base url
    QString deckString = "https://" + getDomainForWebsite(website) + "/?";

    // export all cards in zone
    QString mainBoardCards = toDecklistExportString(deckList.getCardNodes({DECK_ZONE_MAIN}));
    QString sideBoardCards = toDecklistExportString(deckList.getCardNodes({DECK_ZONE_SIDE}));

    // Remove the extra return at the end of the last cards
    mainBoardCards.chop(3);
    sideBoardCards.chop(3);
    // if after we've called it for each card, and the strings are empty, we know that
    // there were no non-token cards in the deck, so show an error message.
    if ((QString::compare(mainBoardCards, "", Qt::CaseInsensitive) == 0) &&
        (QString::compare(sideBoardCards, "", Qt::CaseInsensitive) == 0)) {
        return "";
    }
    // return a string with the url for decklist export
    deckString += "deckmain=" + mainBoardCards + "&deckside=" + sideBoardCards;
    return deckString;
}

void DeckLoader::saveToClipboard(const DeckList &deckList, bool addComments, bool addSetNameAndNumber)
{
    QString buffer;
    QTextStream stream(&buffer);
    saveToStream_Plain(stream, deckList, addComments, addSetNameAndNumber);
    QApplication::clipboard()->setText(buffer, QClipboard::Clipboard);
    QApplication::clipboard()->setText(buffer, QClipboard::Selection);
}

bool DeckLoader::saveToStream_Plain(QTextStream &out,
                                    const DeckList &deckList,
                                    bool addComments,
                                    bool addSetNameAndNumber)
{
    if (addComments) {
        saveToStream_DeckHeader(out, deckList);
    }

    // loop zones
    for (auto zoneNode : deckList.getZoneNodes()) {
        saveToStream_DeckZone(out, zoneNode, addComments, addSetNameAndNumber);

        // end of zone
        out << "\n";
    }

    return true;
}

void DeckLoader::saveToStream_DeckHeader(QTextStream &out, const DeckList &deckList)
{
    if (!deckList.getName().isEmpty()) {
        out << "// " << deckList.getName() << "\n\n";
    }

    if (!deckList.getComments().isEmpty()) {
        QStringList commentRows = deckList.getComments().split(QRegularExpression("\n|\r\n|\r"));
        for (const QString &row : commentRows) {
            out << "// " << row << "\n";
        }
        out << "\n";
    }
}

void DeckLoader::saveToStream_DeckZone(QTextStream &out,
                                       const InnerDecklistNode *zoneNode,
                                       bool addComments,
                                       bool addSetNameAndNumber,
                                       const QString &boardZoneName)
{
    // Nested sub-zones keep their owning board's identity: the top-level call
    // passes no board, so the zone's own name is used; recursive calls carry the
    // owning board down so the sideboard marker survives sub-zone nesting.
    const QString owningBoardZoneName = boardZoneName.isEmpty() ? zoneNode->getName() : boardZoneName;

    // group cards by card type and count the subtotals
    QMultiMap<QString, DecklistCardNode *> cardsByType;
    QMap<QString, int> cardTotalByType;
    int cardTotal = 0;
    QList<const InnerDecklistNode *> subZones;

    for (int j = 0; j < zoneNode->size(); j++) {
        auto *card = dynamic_cast<DecklistCardNode *>(zoneNode->at(j));
        if (!card) {
            // Cards collected in nested sub-zones are exported by recursion so
            // they don't end up invisible in the plain text output. They are
            // deferred until after this zone's own header and cards so they read
            // as part of this zone's block.
            if (auto *subZone = dynamic_cast<const InnerDecklistNode *>(zoneNode->at(j))) {
                subZones.append(subZone);
            }
            continue;
        }

        CardInfoPtr info = CardDatabaseManager::query()->getCardInfo(card->getName());
        QString cardType = info ? info->getMainCardType() : "unknown";

        cardsByType.insert(cardType, card);

        if (cardTotalByType.contains(cardType)) {
            cardTotalByType[cardType] += card->getNumber();
        } else {
            cardTotalByType[cardType] = card->getNumber();
        }

        cardTotal += card->getNumber();
    }

    if (addComments) {
        out << "// " << cardTotal << " " << zoneNode->getVisibleName() << "\n";
    }

    // print cards to stream
    for (const QString &cardType : cardsByType.uniqueKeys()) {
        if (addComments) {
            out << "// " << cardTotalByType[cardType] << " " << cardType << "\n";
        }

        QList<DecklistCardNode *> cards = cardsByType.values(cardType);

        saveToStream_DeckZoneCards(out, cards, addComments, addSetNameAndNumber, owningBoardZoneName);

        if (addComments) {
            out << "\n";
        }
    }

    // Nested sub-zones come last, after the parent's own header and cards.
    for (const auto *subZone : subZones) {
        saveToStream_DeckZone(out, subZone, addComments, addSetNameAndNumber, owningBoardZoneName);
    }
}

void DeckLoader::saveToStream_DeckZoneCards(QTextStream &out,
                                            QList<DecklistCardNode *> cards,
                                            bool addComments,
                                            bool addSetNameAndNumber,
                                            const QString &boardZoneName)
{
    // QMultiMap sorts values in reverse order
    for (int i = cards.size() - 1; i >= 0; --i) {
        DecklistCardNode *card = cards[i];

        if (boardZoneName == DECK_ZONE_SIDE && addComments) {
            out << "SB: ";
        }

        if (card->getNumber()) {
            out << card->getNumber();
        }
        if (!card->getName().isNull() && !card->getName().isEmpty()) {
            out << " " << card->getName();
        }
        if (addSetNameAndNumber) {
            if (!card->getCardSetShortName().isNull() && !card->getCardSetShortName().isEmpty()) {
                out << " " << "(" << card->getCardSetShortName() << ")";
            }
            if (!card->getCardCollectorNumber().isNull()) {
                out << " " << card->getCardCollectorNumber();
            }
        }
        out << "\n";
    }
}

bool DeckLoader::convertToCockatriceFormat(LoadedDeck &deck)
{
    QString fileName = deck.lastLoadInfo.fileName;
    if (fileName.isEmpty()) {
        return false;
    }

    // Determine the format before touching any file, so an already-converted or
    // unsupported deck never truncates or deletes anything.
    switch (DeckFileFormat::getFormatFromName(fileName)) {
        case DeckFileFormat::PlainText:
            break;
        case DeckFileFormat::Cockatrice:
            qCInfo(DeckLoaderLog) << "File is already in Cockatrice format. No conversion needed.";
            return true;
        default:
            qCWarning(DeckLoaderLog) << "Unsupported file format for conversion:" << fileName;
            return false;
    }

    // Change the file extension to .cod
    QFileInfo fileInfo(fileName);
    QString newFileName = QDir::toNativeSeparators(fileInfo.path() + "/" + fileInfo.completeBaseName() + ".cod");

    // Use QSaveFile so a failed write (e.g. a full disk) cannot leave a 0-byte .cod
    // behind and then delete the original deck.
    QSaveFile file(newFileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
        qCWarning(DeckLoaderLog) << "Failed to open file for writing:" << newFileName;
        return false;
    }

    if (!deck.deckList.saveToFile_Native(&file)) {
        file.cancelWriting();
        qCWarning(DeckLoaderLog) << "Failed to serialize deck for file:" << newFileName;
        return false;
    }

    if (!file.commit()) {
        qCWarning(DeckLoaderLog) << "Failed to convert deck to " << newFileName << ":" << file.errorString();
        return false;
    }

    // Conversion succeeded: delete the original file.
    if (!QFile::remove(fileName)) {
        qCWarning(DeckLoaderLog) << "Failed to delete original file:" << fileName;
    } else {
        qCInfo(DeckLoaderLog) << "Original file deleted successfully:" << fileName;
    }
    deck.lastLoadInfo = {
        .fileName = newFileName,
        .fileFormat = DeckFileFormat::Cockatrice,
    };

    return true;
}

void DeckLoader::printDeckListNode(QTextCursor *cursor, const InnerDecklistNode *node)
{
    if (!node || node->isEmpty()) {
        return;
    }

    const int totalColumns = 2;

    // Dispatch children by type instead of trusting a whole-node height: a deck
    // node may hold direct cards and nested zones side by side (custom zones),
    // and an empty node would previously crash on at(0).
    QVector<const AbstractDecklistCardNode *> cards;
    QVector<const InnerDecklistNode *> subZones;
    for (int i = 0; i < node->size(); i++) {
        if (auto *card = dynamic_cast<const AbstractDecklistCardNode *>(node->at(i))) {
            cards.append(card);
        } else if (auto *zone = dynamic_cast<const InnerDecklistNode *>(node->at(i))) {
            subZones.append(zone);
        }
    }

    if (!cards.isEmpty()) {
        QTextBlockFormat blockFormat;
        QTextCharFormat charFormat;
        charFormat.setFontPointSize(11);
        charFormat.setFontWeight(QFont::Bold);
        cursor->insertBlock(blockFormat, charFormat);

        QTextTableFormat tableFormat;
        tableFormat.setCellPadding(0);
        tableFormat.setCellSpacing(0);
        tableFormat.setBorder(0);
        QTextTable *table = cursor->insertTable(cards.size() + 1, totalColumns, tableFormat);
        for (int i = 0; i < cards.size(); i++) {
            const AbstractDecklistCardNode *card = cards[i];

            QTextCharFormat cellCharFormat;
            cellCharFormat.setFontPointSize(9);

            QTextTableCell cell = table->cellAt(i, 0);
            cell.setFormat(cellCharFormat);
            QTextCursor cellCursor = cell.firstCursorPosition();
            cellCursor.insertText(QString("%1 ").arg(card->getNumber()));

            cell = table->cellAt(i, 1);
            cell.setFormat(cellCharFormat);
            cellCursor = cell.firstCursorPosition();
            cellCursor.insertText(card->getName());
        }
    }

    for (const InnerDecklistNode *subZone : subZones) {
        if (subZone->isEmpty()) {
            continue;
        }

        QTextBlockFormat blockFormat;
        QTextCharFormat charFormat;
        charFormat.setFontPointSize(14);
        charFormat.setFontWeight(QFont::Bold);

        cursor->insertBlock(blockFormat, charFormat);

        QTextTableFormat tableFormat;
        tableFormat.setCellPadding(10);
        tableFormat.setCellSpacing(0);
        tableFormat.setBorder(0);
        QVector<QTextLength> constraints;
        for (int i = 0; i < totalColumns; i++) {
            constraints << QTextLength(QTextLength::PercentageLength, 100.0 / totalColumns);
        }
        tableFormat.setColumnWidthConstraints(constraints);

        QTextTable *table = cursor->insertTable(1, totalColumns, tableFormat);
        QTextCursor cellCursor = table->cellAt(0, 0).firstCursorPosition();
        printDeckListNode(&cellCursor, subZone);
    }

    cursor->movePosition(QTextCursor::End);
}

void DeckLoader::printDeckList(QPrinter *printer, const DeckList &deckList)
{
    QTextDocument doc;

    QFont font("Serif");
    font.setStyleHint(QFont::Serif);
    doc.setDefaultFont(font);

    QTextCursor cursor(&doc);

    QTextBlockFormat headerBlockFormat;
    QTextCharFormat headerCharFormat;
    headerCharFormat.setFontPointSize(16);
    headerCharFormat.setFontWeight(QFont::Bold);

    cursor.insertBlock(headerBlockFormat, headerCharFormat);
    cursor.insertText(deckList.getName());

    headerCharFormat.setFontPointSize(12);
    cursor.insertBlock(headerBlockFormat, headerCharFormat);
    cursor.insertText(deckList.getComments());
    cursor.insertBlock(headerBlockFormat, headerCharFormat);

    for (auto zoneNode : deckList.getZoneNodes()) {
        cursor.insertHtml("<br><img src=theme:hr.jpg>");
        cursor.insertBlock(headerBlockFormat, headerCharFormat);

        printDeckListNode(&cursor, zoneNode);
    }

    doc.print(printer);
}