//    Copyright (C) 2020 Jakub Melka
//
//    This file is part of PdfForQt.
//
//    PdfForQt is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Lesser General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    (at your option) any later version.
//
//    PdfForQt 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 Lesser General Public License for more details.
//
//    You should have received a copy of the GNU Lesser General Public License
//    along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.

#include "pdfform.h"
#include "pdfdocument.h"

namespace pdf
{

PDFForm PDFForm::parse(const PDFObjectStorage* storage, PDFObject object)
{
    PDFForm form;

    if (const PDFDictionary* formDictionary = storage->getDictionaryFromObject(object))
    {
        PDFDocumentDataLoaderDecorator loader(storage);

        std::vector<PDFObjectReference> fieldRoots = loader.readReferenceArrayFromDictionary(formDictionary, "Fields");
        form.m_formFields.reserve(fieldRoots.size());
        for (const PDFObjectReference& fieldRootReference : fieldRoots)
        {
            form.m_formFields.emplace_back(PDFFormField::parse(storage, fieldRootReference, nullptr));
        }

        form.m_formType = FormType::AcroForm;
        form.m_needAppearances = loader.readBooleanFromDictionary(formDictionary, "NeedAppearances", false);
        form.m_signatureFlags = static_cast<SignatureFlags>(loader.readIntegerFromDictionary(formDictionary, "SigFlags", 0));
        form.m_calculationOrder = loader.readReferenceArrayFromDictionary(formDictionary, "CO");
        form.m_resources = formDictionary->get("DR");
        form.m_defaultAppearance = loader.readOptionalStringFromDictionary(formDictionary, "DA");
        form.m_quadding = loader.readOptionalIntegerFromDictionary(formDictionary, "Q");
        form.m_xfa = formDictionary->get("XFA");

        if (!form.m_xfa.isNull())
        {
            // Jakub Melka: handle XFA form
            form.m_formType = FormType::XFAForm;
        }
    }

    return form;
}

PDFFormFieldPointer PDFFormField::parse(const PDFObjectStorage* storage, PDFObjectReference reference, PDFFormField* parentField)
{
    PDFFormFieldPointer result;

    if (const PDFDictionary* fieldDictionary = storage->getDictionaryFromObject(storage->getObjectByReference(reference)))
    {
        PDFFormField* formField = nullptr;
        PDFFormFieldButton* formFieldButton = nullptr;
        PDFFormFieldText* formFieldText = nullptr;
        PDFFormFieldChoice* formFieldChoice = nullptr;
        PDFFormFieldSignature* formFieldSignature = nullptr;

        constexpr const std::array<std::pair<const char*, FieldType>, 4> fieldTypes = {
            std::pair<const char*, FieldType>{ "Btn", FieldType::Button },
            std::pair<const char*, FieldType>{ "Tx", FieldType::Text },
            std::pair<const char*, FieldType>{ "Ch", FieldType::Choice },
            std::pair<const char*, FieldType>{ "Sig", FieldType::Signature }
        };

        PDFDocumentDataLoaderDecorator loader(storage);
        FieldType formFieldType = parentField ? parentField->getFieldType() : FieldType::Invalid;
        if (fieldDictionary->hasKey("FT"))
        {
            formFieldType = loader.readEnumByName(fieldDictionary->get("FT"), fieldTypes.begin(), fieldTypes.end(), FieldType::Invalid);
        }

        switch (formFieldType)
        {
            case FieldType::Invalid:
                formField = new PDFFormField();
                break;

            case FieldType::Button:
                formFieldButton = new PDFFormFieldButton();
                formField = formFieldButton;
                break;

            case FieldType::Text:
                formFieldText = new PDFFormFieldText();
                formField = formFieldText;
                break;

            case FieldType::Choice:
                formFieldChoice = new PDFFormFieldChoice();
                formField = formFieldChoice;
                break;

            case FieldType::Signature:
                formFieldSignature = new PDFFormFieldSignature();
                formField = formFieldSignature;
                break;

            default:
                Q_ASSERT(false);
                break;
        }
        result.reset(formField);

        std::vector<PDFObjectReference> kids = loader.readReferenceArrayFromDictionary(fieldDictionary, "Kids");
        if (kids.empty())
        {
            // This means, that field's dictionary is merged with annotation's dictionary,
            // so, we will add pointer to self to the form widgets. But we must test, if we
            // really have merged annotation's dictionary - we test it by checking for 'Subtype'
            // presence.
            if (loader.readNameFromDictionary(fieldDictionary, "Subtype") == "Widget")
            {
                formField->m_widgets.emplace_back(PDFFormWidget::parse(storage, reference, formField));
            }
        }
        else
        {
            // Otherwise we must scan all references, and determine, if kid is another form field,
            // or it is a widget annotation. Widget annotations has required field 'Subtype', which
            // has value 'Widget', form field has required field 'Parent' (for non-root fields).

            for (const PDFObjectReference& kid : kids)
            {
                if (const PDFDictionary* childDictionary = storage->getDictionaryFromObject(storage->getObjectByReference(kid)))
                {
                    const bool isWidget = loader.readNameFromDictionary(childDictionary, "Subtype") == "Widget";
                    const bool isField = loader.readReferenceFromDictionary(childDictionary, "Parent").isValid();

                    if (isField)
                    {
                        // This is form field (potentially merged with widget)
                        formField->m_childFields.emplace_back(PDFFormField::parse(storage, kid, formField));
                    }
                    else if (isWidget)
                    {
                        // This is pure widget (with no form field)
                        formField->m_widgets.emplace_back(PDFFormWidget::parse(storage, kid, formField));
                    }
                }
            }

        }

        PDFObject parentV = parentField ? parentField->getValue() : PDFObject();
        PDFObject parentDV = parentField ? parentField->getDefaultValue() : PDFObject();
        FieldFlags parentFlags = parentField ? parentField->getFlags() : None;

        formField->m_selfReference = reference;
        formField->m_fieldType = formFieldType;
        formField->m_parentField = parentField;
        formField->m_fieldNames[Partial] = loader.readTextStringFromDictionary(fieldDictionary, "T", QString());
        formField->m_fieldNames[UserCaption] = loader.readTextStringFromDictionary(fieldDictionary, "TU", QString());
        formField->m_fieldNames[Export] = loader.readTextStringFromDictionary(fieldDictionary, "TM", QString());
        formField->m_fieldNames[FullyQualified] = parentField ? QString("%1.%2").arg(parentField->getName(FullyQualified), formField->m_fieldNames[Partial]) : formField->m_fieldNames[Partial];
        formField->m_fieldFlags = fieldDictionary->hasKey("Ff") ? static_cast<FieldFlags>(loader.readIntegerFromDictionary(fieldDictionary, "Ff", 0)) : parentFlags;
        formField->m_value = fieldDictionary->hasKey("V") ? fieldDictionary->get("V") : parentV;
        formField->m_defaultValue = fieldDictionary->hasKey("DV") ? fieldDictionary->get("DV") : parentDV;
        formField->m_additionalActions = PDFAnnotationAdditionalActions::parse(storage, fieldDictionary->get("AA"));

        if (formFieldButton)
        {
            formFieldButton->m_options = loader.readTextStringList(fieldDictionary->get("Opt"));
        }

        if (formFieldText)
        {
            PDFInteger maxLengthDefault = 0;

            if (PDFFormFieldText* parentTextField = dynamic_cast<PDFFormFieldText*>(parentField))
            {
                maxLengthDefault = parentTextField->getTextMaximalLength();
            }

            formFieldText->m_maxLength = loader.readIntegerFromDictionary(fieldDictionary, "MaxLen", maxLengthDefault);
        }

        if (formFieldChoice)
        {
            // Parse options - it is array of options values. Option value can be either a single text
            // string, or array of two values - export value and text to be displayed.
            PDFObject options = storage->getObject(fieldDictionary->get("Opt"));
            if (options.isArray())
            {
                const PDFArray* optionsArray = options.getArray();
                formFieldChoice->m_options.reserve(optionsArray->getCount());
                for (size_t i = 0; i < optionsArray->getCount(); ++i)
                {
                    PDFFormFieldChoice::Option option;

                    PDFObject optionItemObject = storage->getObject(optionsArray->getItem(i));
                    if (optionItemObject.isArray())
                    {
                        QStringList stringList = loader.readTextStringList(optionItemObject);
                        if (stringList.size() == 2)
                        {
                            option.exportString = stringList[0];
                            option.userString = stringList[1];
                        }
                    }
                    else
                    {
                        option.userString = loader.readTextString(optionItemObject, QString());
                        option.exportString = option.userString;
                    }

                    formFieldChoice->m_options.emplace_back(qMove(option));
                }
            }

            formFieldChoice->m_topIndex = loader.readIntegerFromDictionary(fieldDictionary, "TI", 0);
        }
    }

    return result;
}

PDFFormWidget::PDFFormWidget(PDFObjectReference widget, PDFFormField* parentField) :
    m_widget(widget),
    m_parentField(parentField)
{

}

PDFFormWidget PDFFormWidget::parse(const PDFObjectStorage* storage, PDFObjectReference reference, PDFFormField* parentField)
{
    Q_UNUSED(storage);
    return PDFFormWidget(reference, parentField);
}

PDFFormFieldButton::ButtonType PDFFormFieldButton::getButtonType() const
{
    if (m_fieldFlags.testFlag(PushButton))
    {
        return ButtonType::PushButton;
    }
    else if (m_fieldFlags.testFlag(Radio))
    {
        return ButtonType::RadioButton;
    }

    return ButtonType::CheckBox;
}

}   // namespace pdf