#include "dialogs/InpaintPreviewDialog.h"

#include <QDialogButtonBox>
#include <QEvent>
#include <QLabel>
#include <QPixmap>
#include <QResizeEvent>
#include <QShowEvent>
#include <QSplitter>
#include <QTimer>
#include <QVBoxLayout>

static QLabel* makeImageLabel(QWidget* parent) {
    auto* lab = new QLabel(parent);
    lab->setBackgroundRole(QPalette::Base);
    lab->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    lab->setScaledContents(false);
    lab->setAlignment(Qt::AlignCenter);
    lab->setMinimumSize(1, 1);
    return lab;
}

InpaintPreviewDialog::InpaintPreviewDialog(const QString& title, QWidget* parent)
    : QDialog(parent) {
    setModal(true);
    setMinimumSize(880, 520);
    setWindowTitle(title);

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

    m_beforeLabel = makeImageLabel(this);
    m_afterLabel = makeImageLabel(this);
    m_beforeLabel->installEventFilter(this);
    m_afterLabel->installEventFilter(this);

    auto* splitter = new QSplitter(Qt::Horizontal, this);
    splitter->addWidget(m_beforeLabel);
    splitter->addWidget(m_afterLabel);
    splitter->setStretchFactor(0, 1);
    splitter->setStretchFactor(1, 1);
    root->addWidget(splitter, 1);

    auto* btns = new QDialogButtonBox(this);
    btns->addButton(QStringLiteral("取消"), QDialogButtonBox::RejectRole);
    btns->addButton(QStringLiteral("写回"), QDialogButtonBox::AcceptRole);
    connect(btns, &QDialogButtonBox::accepted, this, &QDialog::accept);
    connect(btns, &QDialogButtonBox::rejected, this, &QDialog::reject);
    root->addWidget(btns);
}

void InpaintPreviewDialog::setImages(const QImage& before, const QImage& after) {
    m_beforeImg = before;
    m_afterImg = after;
    updateScaledPreviews();
    QTimer::singleShot(0, this, [this]() { updateScaledPreviews(); });
}

void InpaintPreviewDialog::resizeEvent(QResizeEvent* e) {
    QDialog::resizeEvent(e);
    updateScaledPreviews();
}

void InpaintPreviewDialog::showEvent(QShowEvent* e) {
    QDialog::showEvent(e);
    updateScaledPreviews();
}

bool InpaintPreviewDialog::eventFilter(QObject* watched, QEvent* event) {
    if (!m_inUpdateScaledPreviews && event->type() == QEvent::Resize) {
        if (watched == m_beforeLabel || watched == m_afterLabel) {
            updateScaledPreviews();
        }
    }
    return QDialog::eventFilter(watched, event);
}

void InpaintPreviewDialog::updateScaledPreviews() {
    if (m_inUpdateScaledPreviews) {
        return;
    }
    m_inUpdateScaledPreviews = true;
    auto fit = [](QLabel* lab, const QImage& src) {
        if (!lab || src.isNull()) {
            if (lab) {
                lab->clear();
            }
            return;
        }
        const QSize cap = lab->size();
        if (cap.width() < 2 || cap.height() < 2) {
            return;
        }
        const QImage scaled = src.scaled(cap, Qt::KeepAspectRatio, Qt::SmoothTransformation);
        lab->setPixmap(QPixmap::fromImage(scaled));
    };
    fit(m_beforeLabel, m_beforeImg);
    fit(m_afterLabel, m_afterImg);
    m_inUpdateScaledPreviews = false;
}