#include "PicSceneLoader.h"
#include "picscene.h"
#include "pictextitem.h"
#include "PicImageItem.h"
#include "PicDateItem.h"
#include "PicScheduleShiftItem.h"
#include "piccodeitem.h"
#include "PicCounterItem.h"

#include <QFile>
#include <QXmlStreamReader>
#include <QXmlStreamWriter>
#include <QXmlStreamAttributes>
#include <QDebug>
#include <QImage>
#include <QPainter>
#include <QScopedPointer>
#include <cmath>
#include <unistd.h>

#include "../Printsetting.h"

namespace {

PicTextItem* createSceneItem(SourceType sourceType)
{
    switch (sourceType) {
    case IMAGE:
        return new PicImageItem();
    case DATETIME:
        return new PicDateItem();
    case SCHEDULE_SHIFT:
        return new PicScheduleShiftItem();
    case CODE:
        return new PicCodeItem();
    case COUNTER:
        return new PicCounterItem();
    case TEXT:
    case UNKNOWN:
    default:
        return new PicTextItem(nullptr, nullptr, sourceType);
    }
}

SourceType sourceTypeFromAttrs(const QXmlStreamAttributes& attrs)
{
    if (!attrs.hasAttribute("sourceType")) {
        return SourceType::UNKNOWN;
    }

    bool ok = false;
    int value = attrs.value("sourceType").toInt(&ok);
    if (!ok) {
        return SourceType::UNKNOWN;
    }

    if (value < SourceType::UNKNOWN || value > SourceType::COUNTER) {
        return SourceType::UNKNOWN;
    }

    return static_cast<SourceType>(value);
}

bool parseVbFileElement(QXmlStreamReader& reader, PicScene* scene)
{
    float posX = 0.0f;
    float posY = 0.0f;
    bool condition = false;
    int catchStartValue = -1;
    int catchValue = -1;
    QXmlStreamAttributes itemAttrs;
    QString htmlCData;

    while (!reader.atEnd()) {
        QXmlStreamReader::TokenType token = reader.readNext();
        if (token == QXmlStreamReader::StartElement) {
            const QString elementName = reader.name().toString();
            if (elementName == "pointer_x") {
                posX = reader.readElementText().toDouble();
            } else if (elementName == "pointer_y") {
                posY = reader.readElementText().toDouble();
            } else if (elementName == "Condition") {
                condition = reader.readElementText().toInt() != 0;
            } else if (elementName == "CatchStartValue") {
                catchStartValue = reader.readElementText().toInt();
            } else if (elementName == "CatchValue") {
                catchValue = reader.readElementText().toInt();
            } else if (elementName == "itemAttrs") {
                itemAttrs = reader.attributes();
                reader.skipCurrentElement();
            } else if (elementName == "html_src") {
                reader.skipCurrentElement();
            } else {
                reader.skipCurrentElement();
            }
        } else if (reader.isCDATA()) {
            htmlCData += reader.text().toString();
        } else if (token == QXmlStreamReader::EndElement && reader.name() == "VBfile") {
            break;
        }
    }

    SourceType sourceType = sourceTypeFromAttrs(itemAttrs);
    PicTextItem* item = createSceneItem(sourceType);
    if (!item) {
        // 单个图元损坏不应影响整个文件的其余内容加载。
        qWarning() << "PicSceneLoader: skip invalid VBfile item";
        return true;
    }

    item->setAttrs(itemAttrs);
    item->setPos(posX, posY);
    item->SpecialConditions = condition;
    item->CatchCnt1StartValue = catchStartValue;
    item->CatchCnt1CurrValue = catchValue;

    if (!htmlCData.isEmpty()) {
        item->setHtml(htmlCData);
    }

    scene->addItem(item);
    return true;
}

} // namespace

namespace PicSceneLoader {

bool loadSceneFromFile(const QString& xmlFilename, PicScene* targetScene, PrintSettingModel* outPrintSettings)
{
    if (!targetScene) {
        qWarning() << "PicSceneLoader: targetScene is null";
        return false;
    }

    QFile file(xmlFilename);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        qWarning() << "PicSceneLoader: failed to open" << xmlFilename << file.errorString();
        return false;
    }

    QXmlStreamReader reader(&file);
    PrintSettingModel printSettings;

    // Widget 对 scene 持有长期信号和 view 绑定，因此加载时必须复用现有 scene。
    targetScene->clear();

    while (!reader.atEnd()) {
        reader.readNext();
        if (reader.isStartElement() && reader.name() == "VBfiles") {
            while (reader.readNextStartElement()) {
                if (reader.name() == "VBfile") {
                    if (!parseVbFileElement(reader, targetScene)) {
                        return false;
                    }
                } else if (reader.name() == "PrintSettings") {
                    PrintSettingModel::loadFromXml(printSettings, reader.attributes());
                    reader.skipCurrentElement();
                } else {
                    reader.skipCurrentElement();
                }
            }
        }
    }

    if (reader.hasError()) {
        qWarning() << "PicSceneLoader: XML parse error" << reader.errorString()
                   << "at" << reader.lineNumber() << ":" << reader.columnNumber();
        return false;
    }

    if (outPrintSettings) {
        *outPrintSettings = printSettings;
    }

    return true;
}

QImage previewSceneFromFile(const QString &xmlFilename)
{
    // 预览刻意复用与正常打开相同的加载路径，避免两套逻辑逐渐产生偏差。
    QScopedPointer<PicScene> scene(new PicScene());
    if (!loadSceneFromFile(xmlFilename, scene.data(), nullptr)) {
        return QImage();
    }

    QRectF contentRect = scene->itemsBoundingRect();
    if (!contentRect.isValid() || contentRect.isEmpty()) {
        return QImage(1, 1, QImage::Format_ARGB32_Premultiplied);
    }

    QSize imageSize(qMax<int>(1, int(std::ceil(contentRect.width()))),
                    qMax<int>(1, int(std::ceil(contentRect.height()))));
    QImage image(imageSize, QImage::Format_ARGB32_Premultiplied);
    image.fill(Qt::transparent);

    QPainter painter(&image);
    painter.setRenderHint(QPainter::Antialiasing, true);
    painter.setRenderHint(QPainter::SmoothPixmapTransform, true);

    // 以 itemsBoundingRect 作为渲染源区域，预览图会裁剪到实际内容，而不是整个 sceneRect。
    scene->render(&painter, QRectF(QPointF(0, 0), imageSize), contentRect);
    painter.end();

    return image;
}

bool saveSceneToXmlFile(const QString &xmlFilename, PicScene *scene, const PrintSettingModel *printSettings)
{
    if (!scene)
        return false;

    QFile file(xmlFilename);
    if (!file.open(QFile::WriteOnly | QFile::Text)) {
        qDebug() << QString("Cannot write file %1(%2).").arg(xmlFilename).arg(file.errorString());
        return false;
    }
    QXmlStreamWriter writer(&file);
    writer.setAutoFormatting(true);
    writer.writeStartDocument("1.0", true);
    writer.writeComment(QString::fromLocal8Bit("Vernon Bach graphic scene file"));
    writer.writeDTD(QString::fromLocal8Bit("<!DOCTYPE VBfiles	[ <!ELEMENT VBfiles (VBfile) > <!ELEMENT VBfile (pointer_x,pointer_y,html_src)> <!ELEMENT pointer_x     (#PCDATA)><!ELEMENT pointer_y     (#PCDATA)><!ELEMENT html_src     (#PCDATA)> ]>"));
    writer.writeStartElement("VBfiles");
    writer.writeAttribute("Version", "1.0");

    QList<QGraphicsItem *> items = scene->items();
    foreach (QGraphicsItem *item, items) {
        PicTextItem *picText = qgraphicsitem_cast<PicTextItem*>(item);
        if (picText == nullptr)
            continue;

        writer.writeStartElement("VBfile");
        writer.writeTextElement(QString::fromLocal8Bit("pointer_x"), QString::fromLocal8Bit("%1").arg(picText->pos().x()));
        writer.writeTextElement(QString::fromLocal8Bit("pointer_y"), QString::fromLocal8Bit("%1").arg(picText->pos().y()));
        writer.writeTextElement(QString::fromLocal8Bit("Condition"), QString::fromLocal8Bit("%1").arg(picText->SpecialConditions ? 1 : 0));
        writer.writeTextElement(QString::fromLocal8Bit("CatchStartValue"), QString::fromLocal8Bit("%1").arg(picText->CatchCnt1StartValue));
        writer.writeTextElement(QString::fromLocal8Bit("CatchValue"), QString::fromLocal8Bit("%1").arg(picText->CatchCnt1CurrValue));

        QXmlStreamAttributes attrs;
        attrs.append("sourceType", QString::number(picText->sourceType()));
        if (picText->sourceType() != SourceType::UNKNOWN) {
            picText->saveAttrs(attrs);
        }
        writer.writeStartElement("itemAttrs");
        writer.writeAttributes(attrs);
        writer.writeEndElement();

        writer.writeTextElement(QString::fromLocal8Bit("html_src"), QString::fromLocal8Bit("my_src"));
        writer.writeCDATA(picText->toHtml());
        writer.writeEndElement();
    }

    if (printSettings) {
        writer.writeEmptyElement("PrintSettings");
        PrintSettingModel::saveToXml(*printSettings, writer);
    }

    writer.writeEndElement();
    writer.writeEndDocument();
    fsync(file.handle());
    file.close();
    return true;
}

} // namespace PicSceneLoader