/* ============================================================
 * rekonq
 * ============================================================
 * SPDX-License-Identifier: GPL-3.0-only
 * Copyright (C) 2022 aqua <aqua@iserlohn-fortress.net>
 * ============================================================
 * Description: rekonq bookmarks model
 * ============================================================ */

#include "bookmarkstreeformat_xbel.h"
#include "bookmarkstreeitem.hpp"
#include <QDateTime>
#include <QXmlStreamReader>

inline void readNodeAttributes(BookmarksTreeItem *item, const QXmlStreamAttributes &attributes)
{
  // id
  if (attributes.hasAttribute(xbel::attr_id))
    item->setData(BookmarksTreeItem::Id, attributes.value(xbel::attr_id).toString());

  // added
  if (attributes.hasAttribute(xbel::attr_added)) {
    const auto dateTime = QDateTime::fromString(attributes.value(xbel::attr_added), Qt::ISODate);
    if (!dateTime.isNull() && dateTime.isValid()) item->setData(BookmarksTreeItem::Added, dateTime);
  }
}

inline void readUrlAttributes(BookmarksTreeItem *item, const QXmlStreamAttributes &attributes)
{
  // href (required)
  if (attributes.hasAttribute(xbel::attr_href))
    item->setData(BookmarksTreeItem::Href, attributes.value(xbel::attr_href).toString());

  // visited
  if (attributes.hasAttribute(xbel::attr_visited)) {
    const auto dateTime = QDateTime::fromString(attributes.value(xbel::attr_visited), Qt::ISODate);
    if (!dateTime.isNull() && dateTime.isValid()) item->setData(BookmarksTreeItem::Visited, dateTime);
  }

  // modified
  if (attributes.hasAttribute(xbel::attr_modified)) {
    const auto dateTime = QDateTime::fromString(attributes.value(xbel::attr_modified), Qt::ISODate);
    if (!dateTime.isNull() && dateTime.isValid()) item->setData(BookmarksTreeItem::Modified, dateTime);
  }
}

[[nodiscard]] inline QList<QString> readItemAttributes(BookmarksTreeItem *item, const QXmlStreamAttributes &attr)
{
  QList<QString> errors;

  switch (item->type()) {

  case BookmarksTreeItem::Root:
    if (!attr.hasAttribute(xbel::attr_version)) {
      errors.append({QObject::tr("%1 xbel has no version").arg(__PRETTY_FUNCTION__)});
    }
    else if (attr.value(xbel::attr_version).compare(QLatin1String{xbel::attr_version_value}) != 0) {
      errors.append({QObject::tr("%1 unknown xbel version").arg(__PRETTY_FUNCTION__)});
    }
    readNodeAttributes(item, attr);
    break;

  case BookmarksTreeItem::Folder:
    readNodeAttributes(item, attr);
    if (attr.hasAttribute(xbel::attr_folded))
      item->setExpanded(attr.value(xbel::attr_folded).compare(QLatin1String{xbel::attr_folded_yes}) != 0);
    break;

  case BookmarksTreeItem::Separator:
    break;

  case BookmarksTreeItem::Bookmark:
    readNodeAttributes(item, attr);
    readUrlAttributes(item, attr);
    break;

  case BookmarksTreeItem::Alias:
    if (!attr.hasAttribute(xbel::attr_ref)) {

      errors.append({QObject::tr("%1 Alias has no ref").arg(__PRETTY_FUNCTION__)});
    }
    else
      item->setData(BookmarksTreeItem::Id, attr.value(xbel::attr_ref).toString());
    break;
  }

  return errors;
}

/**
 * Recursively parse XBEL
 * @param reader
 * @param parent
 * @return true if there were errors during parsing
 */
[[nodiscard]] inline QList<QString> readChildElements(QXmlStreamReader &reader, BookmarksTreeItem *parent)
{
  QList<QString> errors;

  while (reader.readNextStartElement()) {
    if (reader.hasError()) {
      errors.append({QObject::tr("%1 error during parsing: %2").arg(__PRETTY_FUNCTION__, reader.errorString())});
    }

    const auto name = reader.name();
    if (name == xbel::elem_title) { parent->setData(BookmarksTreeItem::Title, reader.readElementText()); }
    else if (name == xbel::elem_desc) {
      parent->setData(BookmarksTreeItem::Description, reader.readElementText());
    }
    else if (name == xbel::elem_info) {
      errors += readChildElements(reader, parent);
    }
    else if (name == xbel::elem_metadata) {
      if (reader.attributes().value(xbel::elem_metadata_owner) == QLatin1String{xbel::elem_metadata_owner_value})
        parent->metadata.append(reader.readElementText());
      else
        reader.skipCurrentElement();
    }
    else if (name == xbel::elem_bookmark) {

      auto *item = new BookmarksTreeItem(BookmarksTreeItem::Bookmark, {}, parent);
      errors += readItemAttributes(item, reader.attributes());
      parent->appendChild(item);
      errors += readChildElements(reader, item);
    }
    else if (name == xbel::elem_folder) {
      auto *item = new BookmarksTreeItem(BookmarksTreeItem::Folder, {}, parent);
      errors += readItemAttributes(item, reader.attributes());
      parent->appendChild(item);
      errors += readChildElements(reader, item);
    }
    else if (name == xbel::elem_separator) {
      auto *item = new BookmarksTreeItem(BookmarksTreeItem::Separator, {}, parent);
      parent->appendChild(item);
      reader.skipCurrentElement();
    }
    else if (name == xbel::elem_alias) {
      auto *item = new BookmarksTreeItem(BookmarksTreeItem::Alias, {}, parent);
      item->setData(BookmarksTreeItem::Id, reader.attributes().value(xbel::attr_ref).toString());
      parent->appendChild(item);
      reader.skipCurrentElement();
    }
    else {
      errors.append({QObject::tr("%1 skipping unknown element '%2' on line %3")
                         .arg(__PRETTY_FUNCTION__, name.toString(), QString::number(reader.lineNumber()))});
      reader.skipCurrentElement();
    }
  }

  return errors;
}

QList<QString> xbel::read(QIODevice *device, BookmarksTreeItem *root)
{
  if (!device->isOpen()) { return {QObject::tr("%1 buffer is not open").arg(__PRETTY_FUNCTION__)}; }

  QXmlStreamReader reader(device);
  if (!reader.readNextStartElement()) return {};

  // parse the top-level item attributes
  if (reader.name().compare(QLatin1String{elem_xbel}) != 0)
    return {QObject::tr("%1 Top-level item is not xbel").arg(__PRETTY_FUNCTION__)};

  QList<QString> errors;
  errors += readItemAttributes(root, reader.attributes());
  errors += readChildElements(reader, root);
  return errors;
}