// SPDX-FileCopyrightText: 2026 GXDE OS Team
// SPDX-License-Identifier: GPL-3.0-or-later

#include "chatview.h"

#include <QMimeData>

#include "markdown.h"

#include <QDragEnterEvent>
#include <QDropEvent>
#include <QHBoxLayout>
#include <QScrollBar>
#include <QLabel>
#include <QTextBrowser>
#include <QTextDocument>
#include <QAbstractTextDocumentLayout>
#include <QMimeData>
#include <QTimer>
#include <QToolButton>
#include <QVBoxLayout>

namespace {

constexpr int kAvatarSize = 30;
constexpr int kBubbleMaxWidth = 580;

QString avatarStyle(bool user)
{
    return user ? QStringLiteral("QLabel { background: rgba(74,144,255,0.85); color: white;"
                                 " border-radius: %1px; font-size: 12px; }")
                      .arg(kAvatarSize / 2)
                : QStringLiteral("QLabel { background: rgba(255,255,255,0.14); color: #eaeaea;"
                                 " border-radius: %1px; font-size: 12px; }")
                      .arg(kAvatarSize / 2);
}

QToolButton *actionButton(const QString &text, QWidget *parent)
{
    auto *button = new QToolButton(parent);
    button->setText(text);
    button->setCursor(Qt::PointingHandCursor);
    button->setFocusPolicy(Qt::NoFocus);
    button->setAutoRaise(true);
    button->setStyleSheet(QStringLiteral(
        "QToolButton { color: rgba(160,200,240,0.75); background: transparent; border: none;"
        " font-size: 11px; padding: 2px 4px; }"
        "QToolButton:hover { color: #cfe5ff; }"));
    return button;
}

} // namespace

/** QTextBrowser that grows to fit its document. */
class BubbleText : public QTextBrowser
{
public:
    explicit BubbleText(QWidget *parent = nullptr)
        : QTextBrowser(parent)
    {
        setFrameShape(QFrame::NoFrame);
        setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        setOpenExternalLinks(false);
        setMinimumWidth(160);
        setMaximumWidth(kBubbleMaxWidth);
        setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
        setStyleSheet(QStringLiteral("QTextBrowser { background: transparent; border: none; }"));
        document()->setDocumentMargin(0);
        document()->setDefaultStyleSheet(QStringLiteral(
            "body { color: #ececec; }"
            "pre { background: #2b2b31; }"
            "code { background: #2b2b31; }"
            "a { color: #7aa7d9; }"
            "h1, h2, h3 { margin: 4px 0; }"
            ".li { margin-left: 10px; }"
            ".gap { height: 6px; }"));
        connect(document()->documentLayout(), &QAbstractTextDocumentLayout::documentSizeChanged,
                this, [this]() { fitHeight(); });
    }

    void setContent(const QString &html)
    {
        setHtml(html);
        fitHeight();
    }

protected:
    void resizeEvent(QResizeEvent *event) override
    {
        QTextBrowser::resizeEvent(event);
        fitHeight();
    }

private:
    void fitHeight()
    {
        const int wanted = int(document()->size().height()) + 4;
        if (wanted > 0 && height() != wanted) {
            setFixedHeight(wanted);
        }
    }
};

class MessageRow : public QWidget
{
    Q_OBJECT

public:
    MessageRow(const ChatMessage &message, int index, bool isLast, QWidget *parent = nullptr)
        : QWidget(parent)
        , m_message(message)
        , m_index(index)
        , m_isUser(message.role == QStringLiteral("user"))
        , m_isLast(isLast)
    {
        auto *row = new QHBoxLayout(this);
        row->setContentsMargins(4, 2, 4, 2);
        row->setSpacing(8);

        auto *avatar = new QLabel(m_isUser ? tr("你") : tr("埃"), this);
        avatar->setFixedSize(kAvatarSize, kAvatarSize);
        avatar->setAlignment(Qt::AlignCenter);
        avatar->setStyleSheet(avatarStyle(m_isUser));

        auto *column = new QVBoxLayout;
        column->setContentsMargins(0, 0, 0, 0);
        column->setSpacing(3);

        auto *meta = new QLabel(m_isUser ? tr("你") : tr("小埃"), this);
        meta->setStyleSheet(QStringLiteral("color: rgba(255,255,255,0.4); font-size: 10px;"));
        meta->setAlignment(m_isUser ? Qt::AlignRight : Qt::AlignLeft);
        column->addWidget(meta);

        auto *bubble = new QFrame(this);
        bubble->setMaximumWidth(kBubbleMaxWidth + 26);
        bubble->setStyleSheet(
            m_isUser ? QStringLiteral("QFrame { background: rgba(74,144,255,0.20);"
                                      " border-radius: 12px; }")
                     : QStringLiteral("QFrame { background: rgba(255,255,255,0.065);"
                                      " border-radius: 12px; }"));
        auto *bubbleLayout = new QVBoxLayout(bubble);
        bubbleLayout->setContentsMargins(13, 9, 13, 9);
        bubbleLayout->setSpacing(0);

        if (m_isUser) {
            auto *label = new QLabel(bubble);
            label->setTextFormat(Qt::RichText);
            label->setWordWrap(true);
            label->setTextInteractionFlags(Qt::TextSelectableByMouse);
            label->setMaximumWidth(kBubbleMaxWidth);
            label->setStyleSheet(QStringLiteral("QLabel { color: #f2f2f2; font-size: 13px; }"));
            label->setText(escapedHtml(message.content));
            m_label = label;
            bubbleLayout->addWidget(label);
        } else {
            m_body = new BubbleText(bubble);
            m_body->setContent(markdownToHtml(message.content));
            connect(m_body, &QTextBrowser::anchorClicked, this,
                    [this](const QUrl &url) { Q_EMIT linkActivated(url); });
            bubbleLayout->addWidget(m_body);
        }
        column->addWidget(bubble);

        m_actions = new QWidget(this);
        auto *actions = new QHBoxLayout(m_actions);
        actions->setContentsMargins(2, 0, 2, 0);
        actions->setSpacing(6);

        auto *copy = actionButton(tr("复制"), m_actions);
        connect(copy, &QToolButton::clicked, this,
                [this]() { Q_EMIT copyRequested(m_index); });
        actions->addWidget(copy);

        if (m_isUser) {
            auto *edit = actionButton(tr("编辑"), m_actions);
            connect(edit, &QToolButton::clicked, this,
                    [this]() { Q_EMIT editRequested(m_index); });
            actions->addWidget(edit);
        } else {
            auto *fork = actionButton(tr("分支"), m_actions);
            connect(fork, &QToolButton::clicked, this,
                    [this]() { Q_EMIT forkRequested(m_index); });
            actions->addWidget(fork);
            auto *edit = actionButton(tr("编辑"), m_actions);
            connect(edit, &QToolButton::clicked, this,
                    [this]() { Q_EMIT editRequested(m_index); });
            actions->addWidget(edit);
            auto *retry = actionButton(tr("重试"), m_actions);
            connect(retry, &QToolButton::clicked, this,
                    [this]() { Q_EMIT retryRequested(m_index); });
            actions->addWidget(retry);
        }
        actions->addStretch();
        column->addWidget(m_actions);

        if (m_isUser) {
            row->addStretch(1);
            row->addLayout(column);
            row->addWidget(avatar, 0, Qt::AlignTop);
        } else {
            row->addWidget(avatar, 0, Qt::AlignTop);
            row->addLayout(column);
            row->addStretch(1);
        }
    }

    int rowIndex() const { return m_index; }

    void setContent(const QString &text)
    {
        m_message.content = text;
        if (m_body) {
            m_body->setContent(markdownToHtml(text));
        } else if (m_label) {
            m_label->setText(escapedHtml(text));
        }
    }

signals:
    void copyRequested(int index);
    void editRequested(int index);
    void forkRequested(int index);
    void retryRequested(int index);
    void linkActivated(const QUrl &url);

protected:

private:
    ChatMessage m_message;
    int m_index = -1;
    bool m_isUser = false;
    bool m_isLast = false;
    QWidget *m_actions = nullptr;
    BubbleText *m_body = nullptr;
    QLabel *m_label = nullptr;
};

ChatMessageList::ChatMessageList(QWidget *parent)
    : QScrollArea(parent)
{
    setAcceptDrops(true);
    setWidgetResizable(true);
    setFrameShape(QFrame::NoFrame);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setStyleSheet(QStringLiteral("QScrollArea { background: transparent; border: none; }"));
    viewport()->setStyleSheet(QStringLiteral("background: transparent;"));

    m_container = new QWidget;
    m_container->setStyleSheet(QStringLiteral("background: transparent;"));
    m_layout = new QVBoxLayout(m_container);
    m_layout->setContentsMargins(8, 10, 8, 10);
    m_layout->setSpacing(6);
    m_layout->addStretch(1);
    setWidget(m_container);

    m_welcome = new QWidget(m_container);
    auto *welcomeLayout = new QVBoxLayout(m_welcome);
    welcomeLayout->setContentsMargins(24, 40, 24, 24);
    welcomeLayout->setSpacing(10);
    welcomeLayout->setAlignment(Qt::AlignHCenter | Qt::AlignTop);

    auto *bigAvatar = new QLabel(tr("埃"), m_welcome);
    bigAvatar->setFixedSize(64, 64);
    bigAvatar->setAlignment(Qt::AlignCenter);
    bigAvatar->setStyleSheet(QStringLiteral(
        "QLabel { background: rgba(74,144,255,0.22); color: #cfe5ff; border-radius: 32px;"
        " font-size: 26px; }"));
    welcomeLayout->addWidget(bigAvatar, 0, Qt::AlignHCenter);

    auto *title = new QLabel(tr("你好，我是小埃同学"), m_welcome);
    QFont titleFont = title->font();
    titleFont.setPixelSize(20);
    titleFont.setWeight(QFont::DemiBold);
    title->setFont(titleFont);
    title->setStyleSheet(QStringLiteral("color: rgba(255,255,255,0.9);"));
    welcomeLayout->addWidget(title, 0, Qt::AlignHCenter);

    auto *hint = new QLabel(
        tr("把文件、链接或文字拖进窗口，或者直接输入问题。\n"
           "第一次使用请在左下角「设置」里填入 DeepSeek API Key。"),
        m_welcome);
    hint->setAlignment(Qt::AlignCenter);
    hint->setWordWrap(true);
    hint->setStyleSheet(QStringLiteral("color: rgba(255,255,255,0.5); font-size: 12px;"));
    welcomeLayout->addWidget(hint, 0, Qt::AlignHCenter);

    m_layout->insertWidget(0, m_welcome);
}

void ChatMessageList::setMessages(const QVector<ChatMessage> &messages)
{
    m_messages = messages;
    rebuild();
}

void ChatMessageList::rebuild()
{
    for (MessageRow *row : m_rows) {
        m_layout->removeWidget(row);
        row->deleteLater();
    }
    m_rows.clear();

    bool hasConversation = false;
    for (const ChatMessage &message : m_messages) {
        if (message.role == QStringLiteral("system")) {
            continue;
        }
        hasConversation = true;
    }
    m_welcome->setVisible(!hasConversation);

    const int lastAssistant = [this]() {
        int last = -1;
        for (int i = 0; i < m_messages.size(); ++i) {
            if (m_messages.at(i).role == QStringLiteral("assistant")) {
                last = i;
            }
        }
        return last;
    }();

    for (int i = 0; i < m_messages.size(); ++i) {
        const ChatMessage &message = m_messages.at(i);
        if (message.role == QStringLiteral("system")) {
            if (!message.content.isEmpty()) {
                auto *note = new QLabel(message.content, m_container);
                note->setWordWrap(true);
                note->setAlignment(Qt::AlignCenter);
                note->setStyleSheet(QStringLiteral(
                    "QLabel { color: rgba(255,255,255,0.42); font-size: 11px;"
                    " background: rgba(255,255,255,0.04); border-radius: 8px;"
                    " padding: 6px 10px; }"));
                m_layout->insertWidget(m_layout->count() - 1, note);
            }
            continue;
        }

        auto *row = new MessageRow(message, i, i == lastAssistant, m_container);
        connect(row, &MessageRow::copyRequested, this, &ChatMessageList::copyRequested);
        connect(row, &MessageRow::editRequested, this, &ChatMessageList::editRequested);
        connect(row, &MessageRow::forkRequested, this, &ChatMessageList::forkRequested);
        connect(row, &MessageRow::retryRequested, this, &ChatMessageList::retryRequested);
        connect(row, &MessageRow::linkActivated, this, &ChatMessageList::linkActivated);
        m_layout->insertWidget(m_layout->count() - 1, row);
        m_rows.append(row);
    }

    QTimer::singleShot(0, this, &ChatMessageList::scrollToBottom);
}

void ChatMessageList::appendMessage(const ChatMessage &message)
{
    m_messages.append(message);
    rebuild();
}

void ChatMessageList::updateMessage(int index, const QString &content)
{
    if (index < 0 || index >= m_messages.size()) {
        return;
    }
    m_messages[index].content = content;

    for (MessageRow *row : m_rows) {
        if (row->rowIndex() == index) {
            row->setContent(content);
            break;
        }
    }
    QTimer::singleShot(0, this, &ChatMessageList::scrollToBottom);
}

void ChatMessageList::appendNote(const QString &text)
{
    auto *note = new QLabel(text, m_container);
    note->setWordWrap(true);
    note->setAlignment(Qt::AlignCenter);
    note->setStyleSheet(QStringLiteral(
        "QLabel { color: rgba(255,255,255,0.45); font-size: 11px;"
        " background: rgba(255,255,255,0.04); border-radius: 8px; padding: 5px 10px; }"));
    m_layout->insertWidget(m_layout->count() - 1, note);
    QTimer::singleShot(0, this, &ChatMessageList::scrollToBottom);
}

void ChatMessageList::dragEnterEvent(QDragEnterEvent *event)
{
    if (event->mimeData() &&
        (event->mimeData()->hasUrls() || event->mimeData()->hasText() ||
         event->mimeData()->hasImage())) {
        event->acceptProposedAction();
        return;
    }
    QScrollArea::dragEnterEvent(event);
}

void ChatMessageList::dragMoveEvent(QDragMoveEvent *event)
{
    if (event->mimeData() &&
        (event->mimeData()->hasUrls() || event->mimeData()->hasText() ||
         event->mimeData()->hasImage())) {
        event->acceptProposedAction();
        return;
    }
    QScrollArea::dragMoveEvent(event);
}

void ChatMessageList::dropEvent(QDropEvent *event)
{
    if (event->mimeData() &&
        (event->mimeData()->hasUrls() || event->mimeData()->hasText() ||
         event->mimeData()->hasImage())) {
        Q_EMIT dropped(event->mimeData());
        event->acceptProposedAction();
        return;
    }
    QScrollArea::dropEvent(event);
}

void ChatMessageList::clear()
{
    m_messages.clear();
    rebuild();
}

void ChatMessageList::scrollToBottom()
{
    verticalScrollBar()->setValue(verticalScrollBar()->maximum());
}

#include "chatview.moc"