/*
 * nheko Copyright (C) 2017  Konstantinos Sideris <siderisk@auth.gr>
 *
 * 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 <http://www.gnu.org/licenses/>.
 */

#include <QAbstractTextDocumentLayout>
#include <QApplication>
#include <QBuffer>
#include <QClipboard>
#include <QDebug>
#include <QFileDialog>
#include <QImageReader>
#include <QMimeData>
#include <QMimeDatabase>
#include <QMimeType>
#include <QPainter>
#include <QStyleOption>
#include <QtConcurrent>

#include <variant.hpp>

#include "Cache.h"
#include "ChatPage.h"
#include "Config.h"
#include "TextInputWidget.h"
#include "Utils.h"

static constexpr size_t INPUT_HISTORY_SIZE = 127;
static constexpr int MAX_TEXTINPUT_HEIGHT  = 120;
static constexpr int InputHeight           = 26;
static constexpr int ButtonHeight          = 24;

FilteredTextEdit::FilteredTextEdit(QWidget *parent)
  : QTextEdit{parent}
  , history_index_{0}
  , popup_{parent}
  , previewDialog_{parent}
{
        setFrameStyle(QFrame::NoFrame);
        connect(document()->documentLayout(),
                &QAbstractTextDocumentLayout::documentSizeChanged,
                this,
                &FilteredTextEdit::updateGeometry);
        connect(document()->documentLayout(),
                &QAbstractTextDocumentLayout::documentSizeChanged,
                this,
                [this]() { emit heightChanged(document()->size().toSize().height()); });
        working_history_.push_back("");
        connect(this, &QTextEdit::textChanged, this, &FilteredTextEdit::textChanged);
        setAcceptRichText(false);

        typingTimer_ = new QTimer(this);
        typingTimer_->setInterval(1000);
        typingTimer_->setSingleShot(true);

        connect(typingTimer_, &QTimer::timeout, this, &FilteredTextEdit::stopTyping);
        connect(&previewDialog_,
                &dialogs::PreviewUploadOverlay::confirmUpload,
                this,
                &FilteredTextEdit::uploadData);

        connect(this, &FilteredTextEdit::resultsRetrieved, this, &FilteredTextEdit::showResults);
        connect(&popup_, &SuggestionsPopup::itemSelected, this, [this](const QString &text) {
                popup_.hide();

                auto cursor   = textCursor();
                const int end = cursor.position();

                cursor.setPosition(atTriggerPosition_, QTextCursor::MoveAnchor);
                cursor.setPosition(end, QTextCursor::KeepAnchor);
                cursor.removeSelectedText();
                cursor.insertText(text);
        });

        // For cycling through the suggestions by hitting tab.
        connect(this,
                &FilteredTextEdit::selectNextSuggestion,
                &popup_,
                &SuggestionsPopup::selectNextSuggestion);
        connect(this,
                &FilteredTextEdit::selectPreviousSuggestion,
                &popup_,
                &SuggestionsPopup::selectPreviousSuggestion);
        connect(this, &FilteredTextEdit::selectHoveredSuggestion, this, [this]() {
                popup_.selectHoveredSuggestion<UserItem>();
        });

        previewDialog_.hide();
}

void
FilteredTextEdit::showResults(const QVector<SearchResult> &results)
{
        QPoint pos;

        if (atTriggerPosition_ != -1) {
                auto cursor = textCursor();
                cursor.setPosition(atTriggerPosition_);
                pos = viewport()->mapToGlobal(cursorRect(cursor).topLeft());
        } else {
                auto rect = cursorRect();
                pos       = viewport()->mapToGlobal(rect.topLeft());
        }

        popup_.addUsers(results);
        popup_.move(pos.x(), pos.y() - popup_.height() - 10);
        popup_.show();
}

void
FilteredTextEdit::keyPressEvent(QKeyEvent *event)
{
        const bool isModifier = (event->modifiers() != Qt::NoModifier);

        if (!isModifier) {
                if (!typingTimer_->isActive())
                        emit startedTyping();

                typingTimer_->start();
        }

        // calculate the new query
        if (textCursor().position() < atTriggerPosition_ || atTriggerPosition_ == -1) {
                resetAnchor();
                closeSuggestions();
        }

        if (popup_.isVisible()) {
                switch (event->key()) {
                case Qt::Key_Down:
                case Qt::Key_Tab:
                        emit selectNextSuggestion();
                        return;
                case Qt::Key_Enter:
                case Qt::Key_Return:
                        emit selectHoveredSuggestion();
                        return;
                case Qt::Key_Escape:
                        closeSuggestions();
                        return;
                case Qt::Key_Up:
                case Qt::Key_Backtab: {
                        emit selectPreviousSuggestion();
                        return;
                }
                default:
                        break;
                }
        }

        switch (event->key()) {
        case Qt::Key_At:
                atTriggerPosition_ = textCursor().position();

                QTextEdit::keyPressEvent(event);
                break;
        case Qt::Key_Return:
        case Qt::Key_Enter:
                if (!(event->modifiers() & Qt::ShiftModifier)) {
                        stopTyping();
                        submit();
                } else {
                        QTextEdit::keyPressEvent(event);
                }
                break;
        case Qt::Key_Up: {
                auto initial_cursor = textCursor();
                QTextEdit::keyPressEvent(event);

                if (textCursor() == initial_cursor && textCursor().atStart() &&
                    history_index_ + 1 < working_history_.size()) {
                        ++history_index_;
                        setPlainText(working_history_[history_index_]);
                        moveCursor(QTextCursor::End);
                } else if (textCursor() == initial_cursor) {
                        // Move to the start of the text if there aren't any lines to move up to.
                        initial_cursor.movePosition(QTextCursor::Start, QTextCursor::MoveAnchor, 1);
                        setTextCursor(initial_cursor);
                }

                break;
        }
        case Qt::Key_Down: {
                auto initial_cursor = textCursor();
                QTextEdit::keyPressEvent(event);

                if (textCursor() == initial_cursor && textCursor().atEnd() && history_index_ > 0) {
                        --history_index_;
                        setPlainText(working_history_[history_index_]);
                        moveCursor(QTextCursor::End);
                } else if (textCursor() == initial_cursor) {
                        // Move to the end of the text if there aren't any lines to move down to.
                        initial_cursor.movePosition(QTextCursor::End, QTextCursor::MoveAnchor, 1);
                        setTextCursor(initial_cursor);
                }

                break;
        }
        default:
                QTextEdit::keyPressEvent(event);

                // Check if the current word should be autocompleted.
                auto cursor = textCursor();
                cursor.movePosition(QTextCursor::StartOfWord, QTextCursor::KeepAnchor);
                auto word = cursor.selectedText();

                if (cursor.position() == 0) {
                        closeSuggestions();
                        return;
                }

                if (cursor.position() == atTriggerPosition_ + 1) {
                        const auto q = query();

                        if (q.isEmpty()) {
                                closeSuggestions();
                                return;
                        }

                        emit showSuggestions(query());
                } else {
                        closeSuggestions();
                }

                break;
        }
}

bool
FilteredTextEdit::canInsertFromMimeData(const QMimeData *source) const
{
        return (source->hasImage() || QTextEdit::canInsertFromMimeData(source));
}

void
FilteredTextEdit::insertFromMimeData(const QMimeData *source)
{
        const auto formats = source->formats().filter("/");
        const auto image   = formats.filter("image/", Qt::CaseInsensitive);
        const auto audio   = formats.filter("audio/", Qt::CaseInsensitive);
        const auto video   = formats.filter("video/", Qt::CaseInsensitive);

        if (!image.empty()) {
                showPreview(source, image);
        } else if (!audio.empty()) {
                showPreview(source, audio);
        } else if (!video.empty()) {
                showPreview(source, video);
        } else if (source->hasUrls()) {
                // Generic file path for any platform.
                QString path;
                for (auto &&u : source->urls()) {
                        if (u.isLocalFile()) {
                                path = u.toLocalFile();
                                break;
                        }
                }

                if (!path.isEmpty() && QFileInfo{path}.exists()) {
                        previewDialog_.setPreview(path);
                } else {
                        qWarning()
                          << "Clipboard does not contain any valid file paths:" << source->urls();
                }
        } else if (source->hasFormat("x-special/gnome-copied-files")) {
                // Special case for X11 users. See "Notes for X11 Users" in source.
                // Source: http://doc.qt.io/qt-5/qclipboard.html

                // This MIME type returns a string with multiple lines separated by '\n'. The first
                // line is the command to perform with the clipboard (not useful to us). The
                // following lines are the file URIs.
                //
                // Source: the nautilus source code in file 'src/nautilus-clipboard.c' in function
                // nautilus_clipboard_get_uri_list_from_selection_data()
                // https://github.com/GNOME/nautilus/blob/master/src/nautilus-clipboard.c

                auto data = source->data("x-special/gnome-copied-files").split('\n');
                if (data.size() < 2) {
                        qWarning() << "MIME format is malformed, cannot perform paste.";
                        return;
                }

                QString path;
                for (int i = 1; i < data.size(); ++i) {
                        QUrl url{data[i]};
                        if (url.isLocalFile()) {
                                path = url.toLocalFile();
                                break;
                        }
                }

                if (!path.isEmpty()) {
                        previewDialog_.setPreview(path);
                } else {
                        qWarning() << "Clipboard does not contain any valid file paths:" << data;
                }
        } else {
                QTextEdit::insertFromMimeData(source);
        }
}

void
FilteredTextEdit::stopTyping()
{
        typingTimer_->stop();
        emit stoppedTyping();
}

QSize
FilteredTextEdit::sizeHint() const
{
        ensurePolished();
        auto margins = viewportMargins();
        margins += document()->documentMargin();
        QSize size = document()->size().toSize();
        size.rwidth() += margins.left() + margins.right();
        size.rheight() += margins.top() + margins.bottom();
        return size;
}

QSize
FilteredTextEdit::minimumSizeHint() const
{
        ensurePolished();
        auto margins = viewportMargins();
        margins += document()->documentMargin();
        margins += contentsMargins();
        QSize size(fontMetrics().averageCharWidth() * 10,
                   fontMetrics().lineSpacing() + margins.top() + margins.bottom());
        return size;
}

void
FilteredTextEdit::submit()
{
        if (toPlainText().trimmed().isEmpty())
                return;

        if (true_history_.size() == INPUT_HISTORY_SIZE)
                true_history_.pop_back();
        true_history_.push_front(toPlainText());
        working_history_ = true_history_;
        working_history_.push_front("");
        history_index_ = 0;

        QString text = toPlainText();

        if (text.startsWith('/')) {
                int command_end = text.indexOf(' ');
                if (command_end == -1)
                        command_end = text.size();
                auto name = text.mid(1, command_end - 1);
                auto args = text.mid(command_end + 1);
                if (name.isEmpty() || name == "/") {
                        message(args);
                } else {
                        command(name, args);
                }
        } else {
                message(std::move(text));
        }

        clear();
}

void
FilteredTextEdit::textChanged()
{
        working_history_[history_index_] = toPlainText();
}

void
FilteredTextEdit::uploadData(const QByteArray data, const QString &media, const QString &filename)
{
        QSharedPointer<QBuffer> buffer{new QBuffer{this}};
        buffer->setData(data);

        emit startedUpload();

        if (media == "image")
                emit image(buffer, filename);
        else if (media == "audio")
                emit audio(buffer, filename);
        else if (media == "video")
                emit video(buffer, filename);
        else
                emit file(buffer, filename);
}

void
FilteredTextEdit::showPreview(const QMimeData *source, const QStringList &formats)
{
        // Retrieve data as MIME type.
        auto const &mime = formats.first();
        QByteArray data  = source->data(mime);
        previewDialog_.setPreview(data, mime);
}

TextInputWidget::TextInputWidget(QWidget *parent)
  : QWidget(parent)
{
        setFont(QFont("Emoji One"));

        setFixedHeight(conf::textInput::height);
        setCursor(Qt::ArrowCursor);

        topLayout_ = new QHBoxLayout();
        topLayout_->setSpacing(0);
        topLayout_->setContentsMargins(15, 0, 15, 0);

        QIcon send_file_icon;
        send_file_icon.addFile(":/icons/icons/ui/paper-clip-outline.png");

        sendFileBtn_ = new FlatButton(this);
        sendFileBtn_->setIcon(send_file_icon);
        sendFileBtn_->setIconSize(QSize(ButtonHeight, ButtonHeight));

        spinner_ = new LoadingIndicator(this);
        spinner_->setFixedHeight(InputHeight);
        spinner_->setFixedWidth(InputHeight);
        spinner_->setObjectName("FileUploadSpinner");
        spinner_->hide();

        QFont font;
        font.setPixelSize(conf::textInputFontSize);

        input_ = new FilteredTextEdit(this);
        input_->setFixedHeight(InputHeight);
        input_->setFont(font);
        input_->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        input_->setPlaceholderText(tr("Write a message..."));

        connect(input_, &FilteredTextEdit::heightChanged, this, [this](int height) {
                int textInputHeight = std::min(MAX_TEXTINPUT_HEIGHT, std::max(height, InputHeight));
                int widgetHeight =
                  std::min(MAX_TEXTINPUT_HEIGHT, std::max(height, conf::textInput::height));

                setFixedHeight(widgetHeight);
                input_->setFixedHeight(textInputHeight);
        });
        connect(input_, &FilteredTextEdit::showSuggestions, this, [this](const QString &q) {
                if (q.isEmpty() || !cache::client())
                        return;

                QtConcurrent::run([this, q = q.toLower().toStdString()]() {
                        try {
                                emit input_->resultsRetrieved(cache::client()->searchUsers(
                                  ChatPage::instance()->currentRoom().toStdString(), q));
                        } catch (const lmdb::error &e) {
                                std::cout << e.what() << '\n';
                        }
                });
        });

        sendMessageBtn_ = new FlatButton(this);

        QIcon send_message_icon;
        send_message_icon.addFile(":/icons/icons/ui/cursor.png");
        sendMessageBtn_->setIcon(send_message_icon);
        sendMessageBtn_->setIconSize(QSize(ButtonHeight, ButtonHeight));

        emojiBtn_ = new emoji::PickButton(this);

        QIcon emoji_icon;
        emoji_icon.addFile(":/icons/icons/ui/smile.png");
        emojiBtn_->setIcon(emoji_icon);
        emojiBtn_->setIconSize(QSize(ButtonHeight, ButtonHeight));

        topLayout_->addWidget(sendFileBtn_);
        topLayout_->addWidget(input_);
        topLayout_->addWidget(emojiBtn_);
        topLayout_->addWidget(sendMessageBtn_);

        setLayout(topLayout_);

        connect(sendMessageBtn_, &FlatButton::clicked, input_, &FilteredTextEdit::submit);
        connect(sendFileBtn_, SIGNAL(clicked()), this, SLOT(openFileSelection()));
        connect(input_, &FilteredTextEdit::message, this, &TextInputWidget::sendTextMessage);
        connect(input_, &FilteredTextEdit::command, this, &TextInputWidget::command);
        connect(input_, &FilteredTextEdit::image, this, &TextInputWidget::uploadImage);
        connect(input_, &FilteredTextEdit::audio, this, &TextInputWidget::uploadAudio);
        connect(input_, &FilteredTextEdit::video, this, &TextInputWidget::uploadVideo);
        connect(input_, &FilteredTextEdit::file, this, &TextInputWidget::uploadFile);
        connect(emojiBtn_,
                SIGNAL(emojiSelected(const QString &)),
                this,
                SLOT(addSelectedEmoji(const QString &)));

        connect(input_, &FilteredTextEdit::startedTyping, this, &TextInputWidget::startedTyping);

        connect(input_, &FilteredTextEdit::stoppedTyping, this, &TextInputWidget::stoppedTyping);

        connect(
          input_, &FilteredTextEdit::startedUpload, this, &TextInputWidget::showUploadSpinner);
}

void
TextInputWidget::addSelectedEmoji(const QString &emoji)
{
        QTextCursor cursor = input_->textCursor();

        QFont emoji_font("Emoji One");
        emoji_font.setPixelSize(conf::emojiSize);

        QFont text_font("Open Sans");
        text_font.setPixelSize(conf::fontSize);

        QTextCharFormat charfmt;
        charfmt.setFont(emoji_font);
        input_->setCurrentCharFormat(charfmt);

        input_->insertPlainText(emoji);
        cursor.movePosition(QTextCursor::End);

        charfmt.setFont(text_font);
        input_->setCurrentCharFormat(charfmt);

        input_->show();
}

void
TextInputWidget::command(QString command, QString args)
{
        if (command == "me") {
                sendEmoteMessage(args);
        } else if (command == "join") {
                sendJoinRoomRequest(args);
        } else if (command == "shrug") {
                sendTextMessage("¯\\_(ツ)_/¯");
        } else if (command == "fliptable") {
                sendTextMessage("(╯°□°)╯︵ ┻━┻");
        }
}

void
TextInputWidget::openFileSelection()
{
        const auto fileName =
          QFileDialog::getOpenFileName(this, tr("Select a file"), "", tr("All Files (*)"));

        if (fileName.isEmpty())
                return;

        QMimeDatabase db;
        QMimeType mime = db.mimeTypeForFile(fileName, QMimeDatabase::MatchContent);

        const auto format = mime.name().split("/")[0];

        QSharedPointer<QFile> file{new QFile{fileName, this}};
        if (format == "image")
                emit uploadImage(file, fileName);
        else if (format == "audio")
                emit uploadAudio(file, fileName);
        else if (format == "video")
                emit uploadVideo(file, fileName);
        else
                emit uploadFile(file, fileName);

        showUploadSpinner();
}

void
TextInputWidget::showUploadSpinner()
{
        topLayout_->removeWidget(sendFileBtn_);
        sendFileBtn_->hide();

        topLayout_->insertWidget(0, spinner_);
        spinner_->start();
}

void
TextInputWidget::hideUploadSpinner()
{
        topLayout_->removeWidget(spinner_);
        topLayout_->insertWidget(0, sendFileBtn_);
        sendFileBtn_->show();
        spinner_->stop();
}

void
TextInputWidget::stopTyping()
{
        input_->stopTyping();
}

void
TextInputWidget::focusInEvent(QFocusEvent *event)
{
        input_->setFocus(event->reason());
}

void
TextInputWidget::paintEvent(QPaintEvent *)
{
        QStyleOption opt;
        opt.init(this);
        QPainter p(this);

        style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);

        p.setPen(QPen(borderColor()));
        p.drawLine(QPointF(0, 0), QPointF(width(), 0));
}

void
TextInputWidget::addReply(const QString &username, const QString &msg)
{
        input_->setText(QString("> %1: %2\n\n").arg(username).arg(msg));
        input_->setFocus();

        auto cursor = input_->textCursor();
        cursor.movePosition(QTextCursor::End);
        input_->setTextCursor(cursor);
}