#include "StickerPanel.h"
#include "StickerCache.h"

#include <QColor>
#include <QFrame>
#include <QGraphicsDropShadowEffect>
#include <QGridLayout>
#include <QIcon>
#include <QLabel>
#include <QPushButton>
#include <QScrollArea>
#include <QShowEvent>
#include <QStackedWidget>
#include <QTabBar>
#include <QVBoxLayout>

StickerPanel::StickerPanel(QWidget *parent)
    : QWidget(parent)
{
    setAttribute(Qt::WA_TranslucentBackground, true);
    setAutoFillBackground(false);
    setFixedSize(376, 276);

    auto *outer = new QVBoxLayout(this);
    outer->setContentsMargins(8, 8, 8, 8);
    outer->setSpacing(0);

    auto *card = new QFrame(this);
    card->setObjectName(QStringLiteral("stickerCard"));
    card->setAttribute(Qt::WA_StyledBackground, true);
    card->setStyleSheet(QStringLiteral(
        "#stickerCard { background:#FFFFFF; border:1px solid #E8E8E8; border-radius:4px; }"));
    auto *shadow = new QGraphicsDropShadowEffect(card);
    shadow->setBlurRadius(22);
    shadow->setOffset(0, 3);
    shadow->setColor(QColor(0, 0, 0, 50));
    card->setGraphicsEffect(shadow);

    auto *lay = new QVBoxLayout(card);
    lay->setContentsMargins(0, 0, 0, 0);
    lay->setSpacing(0);

    m_tabs = new QTabBar(card);
    m_tabs->setDrawBase(false);
    m_tabs->setExpanding(false);
    m_tabs->setStyleSheet(QStringLiteral(
        "QTabBar { background:#FFFFFF; }"
        "QTabBar::tab { height:32px; padding:0 12px; color:#666; background:#FFFFFF; border:none; }"
        "QTabBar::tab:selected { color:#07C160; background:#FFFFFF; }"));
    m_pages = new QStackedWidget(card);
    m_pages->setStyleSheet(QStringLiteral("QStackedWidget { background:#FFFFFF; border:none; }"));
    lay->addWidget(m_tabs);
    lay->addWidget(m_pages, 1);
    outer->addWidget(card);

    connect(m_tabs, &QTabBar::currentChanged, m_pages, &QStackedWidget::setCurrentIndex);
    connect(&StickerCache::instance(), &StickerCache::ready, this, &StickerPanel::rebuild);
    connect(&StickerCache::instance(), &StickerCache::stickerReady, this, [this](qint64, const QString &) {
        rebuild();
    });
}

void StickerPanel::showEvent(QShowEvent *event)
{
    QWidget::showEvent(event);
    reload();
}

void StickerPanel::reload()
{
    if (StickerCache::instance().packs().isEmpty())
        StickerCache::instance().sync();
    else
        rebuild();
}

void StickerPanel::rebuild()
{
    const int keep = m_tabs->currentIndex();
    while (m_tabs->count() > 0)
        m_tabs->removeTab(0);
    while (m_pages->count() > 0)
    {
        QWidget *w = m_pages->widget(0);
        m_pages->removeWidget(w);
        w->deleteLater();
    }
    const auto packs = StickerCache::instance().packs();
    for (int i = 0; i < packs.size(); ++i)
    {
        m_tabs->addTab(packs[i].name);
        m_pages->addWidget(buildPackPage(i));
    }
    if (packs.isEmpty())
    {
        auto *empty = new QLabel(QStringLiteral("表情包加载中…"), m_pages);
        empty->setAlignment(Qt::AlignCenter);
        empty->setStyleSheet(QStringLiteral("color:#B0B0B0; background:#FFFFFF;"));
        m_pages->addWidget(empty);
    }
    if (keep >= 0 && keep < m_tabs->count())
        m_tabs->setCurrentIndex(keep);
}

QWidget *StickerPanel::buildPackPage(int packIndex)
{
    const auto packs = StickerCache::instance().packs();
    auto *page = new QWidget(m_pages);
    page->setStyleSheet(QStringLiteral("background:#FFFFFF;"));
    auto *outer = new QVBoxLayout(page);
    outer->setContentsMargins(0, 0, 0, 0);
    auto *scroll = new QScrollArea(page);
    scroll->setWidgetResizable(true);
    scroll->setFrameShape(QFrame::NoFrame);
    scroll->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    scroll->setStyleSheet(QStringLiteral(
        "QScrollArea { background:#FFFFFF; border:none; }"
        "QScrollBar:vertical { background:#FFFFFF; width:8px; }"
        "QScrollBar::handle:vertical { background:#D0D0D0; border-radius:4px; }"
        "QScrollBar:horizontal { height:0px; }"));
    auto *host = new QWidget(scroll);
    host->setStyleSheet(QStringLiteral("background:#FFFFFF;"));
    auto *grid = new QGridLayout(host);
    grid->setContentsMargins(8, 8, 8, 8);
    grid->setSpacing(4);
    if (packIndex >= 0 && packIndex < packs.size())
    {
        const auto &pack = packs[packIndex];
        int col = 0;
        int row = 0;
        for (const auto &s : pack.stickers)
        {
            auto *btn = new QPushButton(host);
            btn->setFlat(true);
            btn->setCursor(Qt::PointingHandCursor);
            btn->setFixedSize(50, 50);
            btn->setStyleSheet(QStringLiteral(
                "QPushButton { background:#FFFFFF; border:none; border-radius:4px; }"
                "QPushButton:hover { background:#F5F5F5; }"));
            const QPixmap pm = StickerCache::instance().pixmap(pack.id, s.code, 44);
            if (!pm.isNull())
                btn->setIcon(QIcon(pm));
            btn->setIconSize(QSize(44, 44));
            const qint64 packId = pack.id;
            const QString code = s.code;
            connect(btn, &QPushButton::clicked, this, [this, packId, code]() {
                emit stickerPicked(packId, code);
            });
            grid->addWidget(btn, row, col);
            if (++col >= 6)
            {
                col = 0;
                ++row;
            }
        }
    }
    scroll->setWidget(host);
    outer->addWidget(scroll);
    return page;
}