tdlib-fork/td/telegram/WebPageBlock.cpp

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/telegram/WebPageBlock.h"

#include "td/telegram/AnimationsManager.h"
#include "td/telegram/AnimationsManager.hpp"
#include "td/telegram/AudiosManager.h"
#include "td/telegram/AudiosManager.hpp"
#include "td/telegram/ChannelId.h"
#include "td/telegram/ContactsManager.h"
#include "td/telegram/DialogId.h"
#include "td/telegram/Document.h"
#include "td/telegram/DocumentsManager.h"
#include "td/telegram/DocumentsManager.hpp"
#include "td/telegram/files/FileId.h"
#include "td/telegram/Global.h"
#include "td/telegram/Location.h"
#include "td/telegram/Photo.h"
#include "td/telegram/Photo.hpp"
#include "td/telegram/Td.h"
#include "td/telegram/Version.h"
#include "td/telegram/VideosManager.h"
#include "td/telegram/VideosManager.hpp"
#include "td/telegram/VoiceNotesManager.h"
#include "td/telegram/VoiceNotesManager.hpp"
#include "td/telegram/WebPageId.h"

#include "td/utils/common.h"
#include "td/utils/logging.h"
#include "td/utils/misc.h"
#include "td/utils/tl_helpers.h"

#include <type_traits>

namespace td {

class RichText;

struct GetWebPageBlockObjectContext {
  Td *td_ = nullptr;
  Slice base_url_;

  bool is_first_pass_ = true;
  bool has_anchor_urls_ = false;
  std::unordered_map<Slice, const RichText *, SliceHash> anchors_;  // anchor -> text
};

static vector<td_api::object_ptr<td_api::PageBlock>> get_page_block_objects(
    const vector<unique_ptr<WebPageBlock>> &page_blocks, GetWebPageBlockObjectContext *context) {
  return transform(page_blocks, [context](const unique_ptr<WebPageBlock> &page_block) {
    return page_block->get_page_block_object(context);
  });
}

class RichText {
  static vector<td_api::object_ptr<td_api::RichText>> get_rich_text_objects(const vector<RichText> &rich_texts,
                                                                            GetWebPageBlockObjectContext *context) {
    return transform(rich_texts,
                     [context](const RichText &rich_text) { return rich_text.get_rich_text_object(context); });
  }

 public:
  enum class Type : int32 {
    Plain,
    Bold,
    Italic,
    Underline,
    Strikethrough,
    Fixed,
    Url,
    EmailAddress,
    Concatenation,
    Subscript,
    Superscript,
    Marked,
    PhoneNumber,
    Icon,
    Anchor
  };
  Type type = Type::Plain;
  string content;
  vector<RichText> texts;
  FileId document_file_id;
  WebPageId web_page_id;

  bool empty() const {
    return type == Type::Plain && content.empty();
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const {
    if (type == RichText::Type::Icon) {
      CHECK(document_file_id.is_valid());
      Document(Document::Type::General, document_file_id).append_file_ids(td, file_ids);
    } else {
      for (auto &text : texts) {
        text.append_file_ids(td, file_ids);
      }
    }
  }

  td_api::object_ptr<td_api::RichText> get_rich_text_object(GetWebPageBlockObjectContext *context) const {
    switch (type) {
      case RichText::Type::Plain:
        return make_tl_object<td_api::richTextPlain>(content);
      case RichText::Type::Bold:
        return make_tl_object<td_api::richTextBold>(texts[0].get_rich_text_object(context));
      case RichText::Type::Italic:
        return make_tl_object<td_api::richTextItalic>(texts[0].get_rich_text_object(context));
      case RichText::Type::Underline:
        return make_tl_object<td_api::richTextUnderline>(texts[0].get_rich_text_object(context));
      case RichText::Type::Strikethrough:
        return make_tl_object<td_api::richTextStrikethrough>(texts[0].get_rich_text_object(context));
      case RichText::Type::Fixed:
        return make_tl_object<td_api::richTextFixed>(texts[0].get_rich_text_object(context));
      case RichText::Type::Url:
        if (!context->base_url_.empty() && begins_with(content, context->base_url_) &&
            content[context->base_url_.size()] == '#') {
          if (context->is_first_pass_) {
            context->has_anchor_urls_ = true;
          } else {
            auto anchor = Slice(content).substr(context->base_url_.size() + 1);
            auto it = context->anchors_.find(anchor);
            if (it != context->anchors_.end()) {
              if (it->second == nullptr) {
                return make_tl_object<td_api::richTextAnchorLink>(texts[0].get_rich_text_object(context), anchor.str(),
                                                                  content);
              } else {
                context->is_first_pass_ = true;
                auto reference_text = it->second->get_rich_text_object(context);
                context->is_first_pass_ = false;
                return make_tl_object<td_api::richTextReference>(texts[0].get_rich_text_object(context),
                                                                 std::move(reference_text), content);
              }
            }
          }
        }
        return make_tl_object<td_api::richTextUrl>(texts[0].get_rich_text_object(context), content,
                                                   web_page_id.is_valid());
      case RichText::Type::EmailAddress:
        return make_tl_object<td_api::richTextEmailAddress>(texts[0].get_rich_text_object(context), content);
      case RichText::Type::Concatenation:
        return make_tl_object<td_api::richTexts>(get_rich_text_objects(texts, context));
      case RichText::Type::Subscript:
        return make_tl_object<td_api::richTextSubscript>(texts[0].get_rich_text_object(context));
      case RichText::Type::Superscript:
        return make_tl_object<td_api::richTextSuperscript>(texts[0].get_rich_text_object(context));
      case RichText::Type::Marked:
        return make_tl_object<td_api::richTextMarked>(texts[0].get_rich_text_object(context));
      case RichText::Type::PhoneNumber:
        return make_tl_object<td_api::richTextPhoneNumber>(texts[0].get_rich_text_object(context), content);
      case RichText::Type::Icon: {
        auto dimensions = to_integer<uint32>(content);
        auto width = static_cast<int32>(dimensions / 65536);
        auto height = static_cast<int32>(dimensions % 65536);
        return make_tl_object<td_api::richTextIcon>(
            context->td_->documents_manager_->get_document_object(document_file_id), width, height);
      }
      case RichText::Type::Anchor: {
        if (context->is_first_pass_) {
          context->anchors_.emplace(Slice(content), texts[0].empty() ? nullptr : &texts[0]);
        }
        if (texts[0].empty()) {
          return make_tl_object<td_api::richTextAnchor>(content);
        }
        auto result = make_tl_object<td_api::richTexts>();
        result->texts_.push_back(make_tl_object<td_api::richTextAnchor>(content));
        result->texts_.push_back(texts[0].get_rich_text_object(context));
        return std::move(result);
      }
    }
    UNREACHABLE();
    return nullptr;
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(type, storer);
    store(content, storer);
    store(texts, storer);
    if (type == Type::Icon) {
      storer.context()->td().get_actor_unsafe()->documents_manager_->store_document(document_file_id, storer);
    }
    if (type == Type::Url) {
      store(web_page_id, storer);
    }
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(type, parser);
    parse(content, parser);
    parse(texts, parser);
    if (type == Type::Icon) {
      document_file_id = parser.context()->td().get_actor_unsafe()->documents_manager_->parse_document(parser);
      if (!document_file_id.is_valid()) {
        LOG(ERROR) << "Failed to load document from database";
        *this = RichText();
      }
    } else {
      document_file_id = FileId();
    }
    if (type == Type::Url && parser.version() >= static_cast<int32>(Version::SupportInstantView2_0)) {
      parse(web_page_id, parser);
    } else {
      web_page_id = WebPageId();
    }
  }
};

namespace {

class WebPageBlockCaption {
 public:
  RichText text;
  RichText credit;

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const {
    text.append_file_ids(td, file_ids);
    credit.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::pageBlockCaption> get_page_block_caption_object(
      GetWebPageBlockObjectContext *context) const {
    return td_api::make_object<td_api::pageBlockCaption>(text.get_rich_text_object(context),
                                                         credit.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(text, storer);
    store(credit, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(text, parser);
    if (parser.version() >= static_cast<int32>(Version::SupportInstantView2_0)) {
      parse(credit, parser);
    } else {
      credit = RichText();
    }
  }
};

class WebPageBlockTableCell {
 public:
  RichText text;
  bool is_header = false;
  bool align_left = false;
  bool align_center = false;
  bool align_right = false;
  bool valign_top = false;
  bool valign_middle = false;
  bool valign_bottom = false;
  int32 colspan = 1;
  int32 rowspan = 1;

  td_api::object_ptr<td_api::pageBlockTableCell> get_page_block_table_cell_object(
      GetWebPageBlockObjectContext *context) const {
    auto align = [&]() -> td_api::object_ptr<td_api::PageBlockHorizontalAlignment> {
      if (align_left) {
        return td_api::make_object<td_api::pageBlockHorizontalAlignmentLeft>();
      }
      if (align_center) {
        return td_api::make_object<td_api::pageBlockHorizontalAlignmentCenter>();
      }
      if (align_right) {
        return td_api::make_object<td_api::pageBlockHorizontalAlignmentRight>();
      }
      UNREACHABLE();
      return nullptr;
    }();
    auto valign = [&]() -> td_api::object_ptr<td_api::PageBlockVerticalAlignment> {
      if (valign_top) {
        return td_api::make_object<td_api::pageBlockVerticalAlignmentTop>();
      }
      if (valign_middle) {
        return td_api::make_object<td_api::pageBlockVerticalAlignmentMiddle>();
      }
      if (valign_bottom) {
        return td_api::make_object<td_api::pageBlockVerticalAlignmentBottom>();
      }
      UNREACHABLE();
      return nullptr;
    }();
    return td_api::make_object<td_api::pageBlockTableCell>(text.empty() ? nullptr : text.get_rich_text_object(context),
                                                           is_header, colspan, rowspan, std::move(align),
                                                           std::move(valign));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    bool has_text = !text.empty();
    bool has_colspan = colspan != 1;
    bool has_rowspan = rowspan != 1;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(is_header);
    STORE_FLAG(align_left);
    STORE_FLAG(align_center);
    STORE_FLAG(align_right);
    STORE_FLAG(valign_top);
    STORE_FLAG(valign_middle);
    STORE_FLAG(valign_bottom);
    STORE_FLAG(has_text);
    STORE_FLAG(has_colspan);
    STORE_FLAG(has_rowspan);
    END_STORE_FLAGS();
    if (has_text) {
      store(text, storer);
    }
    if (has_colspan) {
      store(colspan, storer);
    }
    if (has_rowspan) {
      store(rowspan, storer);
    }
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    bool has_text;
    bool has_colspan;
    bool has_rowspan;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(is_header);
    PARSE_FLAG(align_left);
    PARSE_FLAG(align_center);
    PARSE_FLAG(align_right);
    PARSE_FLAG(valign_top);
    PARSE_FLAG(valign_middle);
    PARSE_FLAG(valign_bottom);
    PARSE_FLAG(has_text);
    PARSE_FLAG(has_colspan);
    PARSE_FLAG(has_rowspan);
    END_PARSE_FLAGS();
    if (has_text) {
      parse(text, parser);
    }
    if (has_colspan) {
      parse(colspan, parser);
    }
    if (has_rowspan) {
      parse(rowspan, parser);
    }
  }
};

class RelatedArticle {
 public:
  string url;
  WebPageId web_page_id;
  string title;
  string description;
  Photo photo;
  string author;
  int32 published_date = 0;

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    bool has_title = !title.empty();
    bool has_description = !description.empty();
    bool has_photo = photo.id != -2;
    bool has_author = !author.empty();
    bool has_date = published_date != 0;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(has_title);
    STORE_FLAG(has_description);
    STORE_FLAG(has_photo);
    STORE_FLAG(has_author);
    STORE_FLAG(has_date);
    END_STORE_FLAGS();
    store(url, storer);
    store(web_page_id, storer);
    if (has_title) {
      store(title, storer);
    }
    if (has_description) {
      store(description, storer);
    }
    if (has_photo) {
      store(photo, storer);
    }
    if (has_author) {
      store(author, storer);
    }
    if (has_date) {
      store(published_date, storer);
    }
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    bool has_title;
    bool has_description;
    bool has_photo;
    bool has_author;
    bool has_date;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(has_title);
    PARSE_FLAG(has_description);
    PARSE_FLAG(has_photo);
    PARSE_FLAG(has_author);
    PARSE_FLAG(has_date);
    END_PARSE_FLAGS();
    parse(url, parser);
    parse(web_page_id, parser);
    if (has_title) {
      parse(title, parser);
    }
    if (has_description) {
      parse(description, parser);
    }
    if (has_photo) {
      parse(photo, parser);
    } else {
      photo.id = -2;
    }
    if (has_author) {
      parse(author, parser);
    }
    if (has_date) {
      parse(published_date, parser);
    }
  }
};

class WebPageBlockTitle : public WebPageBlock {
  RichText title;

 public:
  WebPageBlockTitle() = default;

  explicit WebPageBlockTitle(RichText &&title) : title(std::move(title)) {
  }

  Type get_type() const override {
    return Type::Title;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    title.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockTitle>(title.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(title, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(title, parser);
  }
};

class WebPageBlockSubtitle : public WebPageBlock {
  RichText subtitle;

 public:
  WebPageBlockSubtitle() = default;
  explicit WebPageBlockSubtitle(RichText &&subtitle) : subtitle(std::move(subtitle)) {
  }

  Type get_type() const override {
    return Type::Subtitle;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    subtitle.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockSubtitle>(subtitle.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(subtitle, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(subtitle, parser);
  }
};

class WebPageBlockAuthorDate : public WebPageBlock {
  RichText author;
  int32 date = 0;

 public:
  WebPageBlockAuthorDate() = default;
  WebPageBlockAuthorDate(RichText &&author, int32 date) : author(std::move(author)), date(max(date, 0)) {
  }

  Type get_type() const override {
    return Type::AuthorDate;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    author.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockAuthorDate>(author.get_rich_text_object(context), date);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(author, storer);
    store(date, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(author, parser);
    parse(date, parser);
  }
};

class WebPageBlockHeader : public WebPageBlock {
  RichText header;

 public:
  WebPageBlockHeader() = default;
  explicit WebPageBlockHeader(RichText &&header) : header(std::move(header)) {
  }

  Type get_type() const override {
    return Type::Header;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    header.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockHeader>(header.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(header, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(header, parser);
  }
};

class WebPageBlockSubheader : public WebPageBlock {
  RichText subheader;

 public:
  WebPageBlockSubheader() = default;
  explicit WebPageBlockSubheader(RichText &&subheader) : subheader(std::move(subheader)) {
  }

  Type get_type() const override {
    return Type::Subheader;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    subheader.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockSubheader>(subheader.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(subheader, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(subheader, parser);
  }
};

class WebPageBlockKicker : public WebPageBlock {
  RichText kicker;

 public:
  WebPageBlockKicker() = default;
  explicit WebPageBlockKicker(RichText &&kicker) : kicker(std::move(kicker)) {
  }

  Type get_type() const override {
    return Type::Kicker;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    kicker.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockKicker>(kicker.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(kicker, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(kicker, parser);
  }
};

class WebPageBlockParagraph : public WebPageBlock {
  RichText text;

 public:
  WebPageBlockParagraph() = default;
  explicit WebPageBlockParagraph(RichText &&text) : text(std::move(text)) {
  }

  Type get_type() const override {
    return Type::Paragraph;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    text.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockParagraph>(text.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(text, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(text, parser);
  }
};

class WebPageBlockPreformatted : public WebPageBlock {
  RichText text;
  string language;

 public:
  WebPageBlockPreformatted() = default;
  WebPageBlockPreformatted(RichText &&text, string &&language) : text(std::move(text)), language(std::move(language)) {
  }

  Type get_type() const override {
    return Type::Preformatted;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    text.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockPreformatted>(text.get_rich_text_object(context), language);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(text, storer);
    store(language, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(text, parser);
    parse(language, parser);
  }
};

class WebPageBlockFooter : public WebPageBlock {
  RichText footer;

 public:
  WebPageBlockFooter() = default;
  explicit WebPageBlockFooter(RichText &&footer) : footer(std::move(footer)) {
  }

  Type get_type() const override {
    return Type::Footer;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    footer.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockFooter>(footer.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(footer, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(footer, parser);
  }
};

class WebPageBlockDivider : public WebPageBlock {
 public:
  Type get_type() const override {
    return Type::Divider;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockDivider>();
  }

  template <class StorerT>
  void store(StorerT &storer) const {
  }

  template <class ParserT>
  void parse(ParserT &parser) {
  }
};

class WebPageBlockAnchor : public WebPageBlock {
  string name;

 public:
  WebPageBlockAnchor() = default;
  explicit WebPageBlockAnchor(string &&name) : name(std::move(name)) {
  }

  Type get_type() const override {
    return Type::Anchor;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    if (context->is_first_pass_) {
      context->anchors_.emplace(name, nullptr);
    }
    return make_tl_object<td_api::pageBlockAnchor>(name);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(name, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(name, parser);
  }
};

class WebPageBlockList : public WebPageBlock {
 public:
  struct Item {
    string label;
    vector<unique_ptr<WebPageBlock>> page_blocks;

    template <class StorerT>
    void store(StorerT &storer) const {
      using ::td::store;
      store(label, storer);
      store(page_blocks, storer);
    }

    template <class ParserT>
    void parse(ParserT &parser) {
      using ::td::parse;
      parse(label, parser);
      parse(page_blocks, parser);
    }
  };

 private:
  vector<Item> items;

  static td_api::object_ptr<td_api::pageBlockListItem> get_page_block_list_item_object(const Item &item,
                                                                                       Context *context) {
    // if label is empty, then Bullet U+2022 is used as a label
    return td_api::make_object<td_api::pageBlockListItem>(item.label.empty() ? "\xE2\x80\xA2" : item.label,
                                                          get_page_block_objects(item.page_blocks, context));
  }

 public:
  WebPageBlockList() = default;
  explicit WebPageBlockList(vector<Item> &&items) : items(std::move(items)) {
  }

  Type get_type() const override {
    return Type::List;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    for (auto &item : items) {
      for (auto &page_block : item.page_blocks) {
        page_block->append_file_ids(td, file_ids);
      }
    }
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return td_api::make_object<td_api::pageBlockList>(
        transform(items, [context](const Item &item) { return get_page_block_list_item_object(item, context); }));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(items, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;

    if (parser.version() >= static_cast<int32>(Version::SupportInstantView2_0)) {
      parse(items, parser);
    } else {
      vector<RichText> text_items;
      bool is_ordered;

      BEGIN_PARSE_FLAGS();
      PARSE_FLAG(is_ordered);
      END_PARSE_FLAGS();

      parse(text_items, parser);

      int pos = 0;
      items.reserve(text_items.size());
      for (auto &text_item : text_items) {
        Item item;
        if (is_ordered) {
          pos++;
          item.label = (PSTRING() << pos << '.');
        }
        item.page_blocks.push_back(make_unique<WebPageBlockParagraph>(std::move(text_item)));
        items.push_back(std::move(item));
      }
    }
  }
};

class WebPageBlockBlockQuote : public WebPageBlock {
  RichText text;
  RichText credit;

 public:
  WebPageBlockBlockQuote() = default;
  WebPageBlockBlockQuote(RichText &&text, RichText &&credit) : text(std::move(text)), credit(std::move(credit)) {
  }

  Type get_type() const override {
    return Type::BlockQuote;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    text.append_file_ids(td, file_ids);
    credit.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockBlockQuote>(text.get_rich_text_object(context),
                                                       credit.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(text, storer);
    store(credit, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(text, parser);
    parse(credit, parser);
  }
};

class WebPageBlockPullQuote : public WebPageBlock {
  RichText text;
  RichText credit;

 public:
  WebPageBlockPullQuote() = default;
  WebPageBlockPullQuote(RichText &&text, RichText &&credit) : text(std::move(text)), credit(std::move(credit)) {
  }

  Type get_type() const override {
    return Type::PullQuote;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    text.append_file_ids(td, file_ids);
    credit.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockPullQuote>(text.get_rich_text_object(context),
                                                      credit.get_rich_text_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(text, storer);
    store(credit, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(text, parser);
    parse(credit, parser);
  }
};

class WebPageBlockAnimation : public WebPageBlock {
  FileId animation_file_id;
  WebPageBlockCaption caption;
  bool need_autoplay = false;

 public:
  WebPageBlockAnimation() = default;
  WebPageBlockAnimation(FileId animation_file_id, WebPageBlockCaption &&caption, bool need_autoplay)
      : animation_file_id(animation_file_id), caption(std::move(caption)), need_autoplay(need_autoplay) {
  }

  Type get_type() const override {
    return Type::Animation;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    caption.append_file_ids(td, file_ids);
    Document(Document::Type::Animation, animation_file_id).append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockAnimation>(
        context->td_->animations_manager_->get_animation_object(animation_file_id, "get_page_block_object"),
        caption.get_page_block_caption_object(context), need_autoplay);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;

    bool has_empty_animation = !animation_file_id.is_valid();
    BEGIN_STORE_FLAGS();
    STORE_FLAG(need_autoplay);
    STORE_FLAG(has_empty_animation);
    END_STORE_FLAGS();

    if (!has_empty_animation) {
      storer.context()->td().get_actor_unsafe()->animations_manager_->store_animation(animation_file_id, storer);
    }
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;

    bool has_empty_animation;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(need_autoplay);
    PARSE_FLAG(has_empty_animation);
    END_PARSE_FLAGS();

    if (parser.version() >= static_cast<int32>(Version::FixWebPageInstantViewDatabase)) {
      if (!has_empty_animation) {
        animation_file_id = parser.context()->td().get_actor_unsafe()->animations_manager_->parse_animation(parser);
      } else {
        animation_file_id = FileId();
      }
    } else {
      animation_file_id = FileId();
      parser.set_error("Wrong stored object");
    }
    parse(caption, parser);
  }
};

class WebPageBlockPhoto : public WebPageBlock {
  Photo photo;
  WebPageBlockCaption caption;
  string url;
  WebPageId web_page_id;

 public:
  WebPageBlockPhoto() = default;
  WebPageBlockPhoto(Photo &&photo, WebPageBlockCaption &&caption, string &&url, WebPageId web_page_id)
      : photo(std::move(photo)), caption(std::move(caption)), url(std::move(url)), web_page_id(web_page_id) {
  }

  Type get_type() const override {
    return Type::Photo;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    append(file_ids, photo_get_file_ids(photo));
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockPhoto>(get_photo_object(context->td_->file_manager_.get(), &photo),
                                                  caption.get_page_block_caption_object(context), url);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(photo, storer);
    store(caption, storer);
    store(url, storer);
    store(web_page_id, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(photo, parser);
    parse(caption, parser);
    if (parser.version() >= static_cast<int32>(Version::SupportInstantView2_0)) {
      parse(url, parser);
      parse(web_page_id, parser);
    } else {
      url.clear();
      web_page_id = WebPageId();
    }
  }
};

class WebPageBlockVideo : public WebPageBlock {
  FileId video_file_id;
  WebPageBlockCaption caption;
  bool need_autoplay = false;
  bool is_looped = false;

 public:
  WebPageBlockVideo() = default;
  WebPageBlockVideo(FileId video_file_id, WebPageBlockCaption &&caption, bool need_autoplay, bool is_looped)
      : video_file_id(video_file_id), caption(std::move(caption)), need_autoplay(need_autoplay), is_looped(is_looped) {
  }

  Type get_type() const override {
    return Type::Video;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    caption.append_file_ids(td, file_ids);
    Document(Document::Type::Video, video_file_id).append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockVideo>(context->td_->videos_manager_->get_video_object(video_file_id),
                                                  caption.get_page_block_caption_object(context), need_autoplay,
                                                  is_looped);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;

    bool has_empty_video = !video_file_id.is_valid();
    BEGIN_STORE_FLAGS();
    STORE_FLAG(need_autoplay);
    STORE_FLAG(is_looped);
    STORE_FLAG(has_empty_video);
    END_STORE_FLAGS();

    if (!has_empty_video) {
      storer.context()->td().get_actor_unsafe()->videos_manager_->store_video(video_file_id, storer);
    }
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;

    bool has_empty_video;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(need_autoplay);
    PARSE_FLAG(is_looped);
    PARSE_FLAG(has_empty_video);
    END_PARSE_FLAGS();

    if (parser.version() >= static_cast<int32>(Version::FixWebPageInstantViewDatabase)) {
      if (!has_empty_video) {
        video_file_id = parser.context()->td().get_actor_unsafe()->videos_manager_->parse_video(parser);
      } else {
        video_file_id = FileId();
      }
    } else {
      video_file_id = FileId();
      parser.set_error("Wrong stored object");
    }
    parse(caption, parser);
  }
};

class WebPageBlockCover : public WebPageBlock {
  unique_ptr<WebPageBlock> cover;

 public:
  WebPageBlockCover() = default;
  explicit WebPageBlockCover(unique_ptr<WebPageBlock> &&cover) : cover(std::move(cover)) {
  }

  Type get_type() const override {
    return Type::Cover;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    cover->append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockCover>(cover->get_page_block_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(cover, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(cover, parser);
  }
};

class WebPageBlockEmbedded : public WebPageBlock {
  string url;
  string html;
  Photo poster_photo;
  Dimensions dimensions;
  WebPageBlockCaption caption;
  bool is_full_width;
  bool allow_scrolling;

 public:
  WebPageBlockEmbedded() = default;
  WebPageBlockEmbedded(string &&url, string &&html, Photo &&poster_photo, Dimensions dimensions,
                       WebPageBlockCaption &&caption, bool is_full_width, bool allow_scrolling)
      : url(std::move(url))
      , html(std::move(html))
      , poster_photo(std::move(poster_photo))
      , dimensions(dimensions)
      , caption(std::move(caption))
      , is_full_width(is_full_width)
      , allow_scrolling(allow_scrolling) {
  }

  Type get_type() const override {
    return Type::Embedded;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    append(file_ids, photo_get_file_ids(poster_photo));
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockEmbedded>(
        url, html, get_photo_object(context->td_->file_manager_.get(), &poster_photo), dimensions.width,
        dimensions.height, caption.get_page_block_caption_object(context), is_full_width, allow_scrolling);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(is_full_width);
    STORE_FLAG(allow_scrolling);
    END_STORE_FLAGS();

    store(url, storer);
    store(html, storer);
    store(poster_photo, storer);
    store(dimensions, storer);
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(is_full_width);
    PARSE_FLAG(allow_scrolling);
    END_PARSE_FLAGS();

    parse(url, parser);
    parse(html, parser);
    parse(poster_photo, parser);
    parse(dimensions, parser);
    parse(caption, parser);
  }
};

class WebPageBlockEmbeddedPost : public WebPageBlock {
  string url;
  string author;
  Photo author_photo;
  int32 date;
  vector<unique_ptr<WebPageBlock>> page_blocks;
  WebPageBlockCaption caption;

 public:
  WebPageBlockEmbeddedPost() = default;
  WebPageBlockEmbeddedPost(string &&url, string &&author, Photo &&author_photo, int32 date,
                           vector<unique_ptr<WebPageBlock>> &&page_blocks, WebPageBlockCaption &&caption)
      : url(std::move(url))
      , author(std::move(author))
      , author_photo(std::move(author_photo))
      , date(max(date, 0))
      , page_blocks(std::move(page_blocks))
      , caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::EmbeddedPost;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    append(file_ids, photo_get_file_ids(author_photo));
    for (auto &page_block : page_blocks) {
      page_block->append_file_ids(td, file_ids);
    }
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockEmbeddedPost>(
        url, author, get_photo_object(context->td_->file_manager_.get(), &author_photo), date,
        get_page_block_objects(page_blocks, context), caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(url, storer);
    store(author, storer);
    store(author_photo, storer);
    store(date, storer);
    store(page_blocks, storer);
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(url, parser);
    parse(author, parser);
    parse(author_photo, parser);
    parse(date, parser);
    parse(page_blocks, parser);
    parse(caption, parser);
  }
};

class WebPageBlockCollage : public WebPageBlock {
  vector<unique_ptr<WebPageBlock>> page_blocks;
  WebPageBlockCaption caption;

 public:
  WebPageBlockCollage() = default;
  WebPageBlockCollage(vector<unique_ptr<WebPageBlock>> &&page_blocks, WebPageBlockCaption &&caption)
      : page_blocks(std::move(page_blocks)), caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::Collage;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    for (auto &page_block : page_blocks) {
      page_block->append_file_ids(td, file_ids);
    }
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockCollage>(get_page_block_objects(page_blocks, context),
                                                    caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(page_blocks, storer);
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(page_blocks, parser);
    parse(caption, parser);
  }
};

class WebPageBlockSlideshow : public WebPageBlock {
  vector<unique_ptr<WebPageBlock>> page_blocks;
  WebPageBlockCaption caption;

 public:
  WebPageBlockSlideshow() = default;
  WebPageBlockSlideshow(vector<unique_ptr<WebPageBlock>> &&page_blocks, WebPageBlockCaption &&caption)
      : page_blocks(std::move(page_blocks)), caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::Slideshow;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    for (auto &page_block : page_blocks) {
      page_block->append_file_ids(td, file_ids);
    }
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockSlideshow>(get_page_block_objects(page_blocks, context),
                                                      caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(page_blocks, storer);
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(page_blocks, parser);
    parse(caption, parser);
  }
};

class WebPageBlockChatLink : public WebPageBlock {
  string title;
  DialogPhoto photo;
  string username;

 public:
  WebPageBlockChatLink() = default;
  WebPageBlockChatLink(string &&title, DialogPhoto photo, string &&username)
      : title(std::move(title)), photo(std::move(photo)), username(std::move(username)) {
  }

  Type get_type() const override {
    return Type::ChatLink;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    append(file_ids, dialog_photo_get_file_ids(photo));
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockChatLink>(
        title, get_chat_photo_object(context->td_->file_manager_.get(), &photo), username);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(title, storer);
    store(photo, storer);
    store(username, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(title, parser);
    parse(photo, parser);
    parse(username, parser);
  }
};

class WebPageBlockAudio : public WebPageBlock {
  FileId audio_file_id;
  WebPageBlockCaption caption;

 public:
  WebPageBlockAudio() = default;
  WebPageBlockAudio(FileId audio_file_id, WebPageBlockCaption &&caption)
      : audio_file_id(audio_file_id), caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::Audio;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    Document(Document::Type::Audio, audio_file_id).append_file_ids(td, file_ids);
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockAudio>(context->td_->audios_manager_->get_audio_object(audio_file_id),
                                                  caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;

    bool has_empty_audio = !audio_file_id.is_valid();
    bool is_voice_note_repaired = true;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(has_empty_audio);
    STORE_FLAG(is_voice_note_repaired);
    END_STORE_FLAGS();

    if (!has_empty_audio) {
      storer.context()->td().get_actor_unsafe()->audios_manager_->store_audio(audio_file_id, storer);
    }
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;

    bool has_empty_audio;
    bool is_voice_note_repaired;
    if (parser.version() >= static_cast<int32>(Version::FixPageBlockAudioEmptyFile)) {
      BEGIN_PARSE_FLAGS();
      PARSE_FLAG(has_empty_audio);
      PARSE_FLAG(is_voice_note_repaired);
      END_PARSE_FLAGS();
    } else {
      has_empty_audio = false;
      is_voice_note_repaired = false;
    }

    if (!has_empty_audio) {
      audio_file_id = parser.context()->td().get_actor_unsafe()->audios_manager_->parse_audio(parser);
    } else {
      if (!is_voice_note_repaired) {
        parser.set_error("Trying to repair WebPageBlockVoiceNote");
      }
      audio_file_id = FileId();
    }
    parse(caption, parser);
  }
};

class WebPageBlockTable : public WebPageBlock {
  RichText title;
  vector<vector<WebPageBlockTableCell>> cells;
  bool is_bordered = false;
  bool is_striped = false;

 public:
  WebPageBlockTable() = default;
  WebPageBlockTable(RichText &&title, vector<vector<WebPageBlockTableCell>> &&cells, bool is_bordered, bool is_striped)
      : title(std::move(title)), cells(std::move(cells)), is_bordered(is_bordered), is_striped(is_striped) {
  }

  Type get_type() const override {
    return Type::Table;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    title.append_file_ids(td, file_ids);
    for (auto &row : cells) {
      for (auto &cell : row) {
        cell.text.append_file_ids(td, file_ids);
      }
    }
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    auto cell_objects = transform(cells, [&](const vector<WebPageBlockTableCell> &row) {
      return transform(
          row, [&](const WebPageBlockTableCell &cell) { return cell.get_page_block_table_cell_object(context); });
    });

    return make_tl_object<td_api::pageBlockTable>(title.get_rich_text_object(context), std::move(cell_objects),
                                                  is_bordered, is_striped);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(is_bordered);
    STORE_FLAG(is_striped);
    END_STORE_FLAGS();
    store(title, storer);
    store(cells, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(is_bordered);
    PARSE_FLAG(is_striped);
    END_PARSE_FLAGS();
    parse(title, parser);
    parse(cells, parser);
  }
};

class WebPageBlockDetails : public WebPageBlock {
  RichText header;
  vector<unique_ptr<WebPageBlock>> page_blocks;
  bool is_open;

 public:
  WebPageBlockDetails() = default;
  WebPageBlockDetails(RichText &&header, vector<unique_ptr<WebPageBlock>> &&page_blocks, bool is_open)
      : header(std::move(header)), page_blocks(std::move(page_blocks)), is_open(is_open) {
  }

  Type get_type() const override {
    return Type::Details;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    header.append_file_ids(td, file_ids);
    for (auto &page_block : page_blocks) {
      page_block->append_file_ids(td, file_ids);
    }
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockDetails>(header.get_rich_text_object(context),
                                                    get_page_block_objects(page_blocks, context), is_open);
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    BEGIN_STORE_FLAGS();
    STORE_FLAG(is_open);
    END_STORE_FLAGS();
    store(header, storer);
    store(page_blocks, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(is_open);
    END_PARSE_FLAGS();
    parse(header, parser);
    parse(page_blocks, parser);
  }
};

class WebPageBlockRelatedArticles : public WebPageBlock {
  RichText header;
  vector<RelatedArticle> related_articles;

 public:
  WebPageBlockRelatedArticles() = default;
  WebPageBlockRelatedArticles(RichText &&header, vector<RelatedArticle> &&related_articles)
      : header(std::move(header)), related_articles(std::move(related_articles)) {
  }

  Type get_type() const override {
    return Type::RelatedArticles;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    header.append_file_ids(td, file_ids);
    for (auto &article : related_articles) {
      if (article.photo.id != -2) {
        append(file_ids, photo_get_file_ids(article.photo));
      }
    }
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    auto related_article_objects = transform(related_articles, [context](const RelatedArticle &article) {
      return td_api::make_object<td_api::pageBlockRelatedArticle>(
          article.url, article.title, article.description,
          get_photo_object(context->td_->file_manager_.get(), &article.photo), article.author, article.published_date);
    });
    return make_tl_object<td_api::pageBlockRelatedArticles>(header.get_rich_text_object(context),
                                                            std::move(related_article_objects));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(header, storer);
    store(related_articles, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(header, parser);
    parse(related_articles, parser);
  }
};

class WebPageBlockMap : public WebPageBlock {
  Location location;
  int32 zoom = 0;
  Dimensions dimensions;
  WebPageBlockCaption caption;

 public:
  WebPageBlockMap() = default;
  WebPageBlockMap(Location location, int32 zoom, Dimensions dimensions, WebPageBlockCaption &&caption)
      : location(std::move(location)), zoom(zoom), dimensions(dimensions), caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::Map;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockMap>(location.get_location_object(), zoom, dimensions.width,
                                                dimensions.height, caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;
    store(location, storer);
    store(zoom, storer);
    store(dimensions, storer);
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;
    parse(location, parser);
    parse(zoom, parser);
    parse(dimensions, parser);
    parse(caption, parser);
  }
};

class WebPageBlockVoiceNote : public WebPageBlock {
  FileId voice_note_file_id;
  WebPageBlockCaption caption;

 public:
  WebPageBlockVoiceNote() = default;
  WebPageBlockVoiceNote(FileId voice_note_file_id, WebPageBlockCaption &&caption)
      : voice_note_file_id(voice_note_file_id), caption(std::move(caption)) {
  }

  Type get_type() const override {
    return Type::VoiceNote;
  }

  void append_file_ids(const Td *td, vector<FileId> &file_ids) const override {
    Document(Document::Type::VoiceNote, voice_note_file_id).append_file_ids(td, file_ids);
    caption.append_file_ids(td, file_ids);
  }

  td_api::object_ptr<td_api::PageBlock> get_page_block_object(Context *context) const override {
    return make_tl_object<td_api::pageBlockVoiceNote>(
        context->td_->voice_notes_manager_->get_voice_note_object(voice_note_file_id),
        caption.get_page_block_caption_object(context));
  }

  template <class StorerT>
  void store(StorerT &storer) const {
    using ::td::store;

    bool has_empty_voice_note = !voice_note_file_id.is_valid();
    BEGIN_STORE_FLAGS();
    STORE_FLAG(has_empty_voice_note);
    END_STORE_FLAGS();

    if (!has_empty_voice_note) {
      storer.context()->td().get_actor_unsafe()->voice_notes_manager_->store_voice_note(voice_note_file_id, storer);
    }
    store(caption, storer);
  }

  template <class ParserT>
  void parse(ParserT &parser) {
    using ::td::parse;

    bool has_empty_voice_note;
    BEGIN_PARSE_FLAGS();
    PARSE_FLAG(has_empty_voice_note);
    END_PARSE_FLAGS();

    if (!has_empty_voice_note) {
      voice_note_file_id = parser.context()->td().get_actor_unsafe()->voice_notes_manager_->parse_voice_note(parser);
    } else {
      voice_note_file_id = FileId();
    }
    parse(caption, parser);
  }
};

vector<RichText> get_rich_texts(vector<tl_object_ptr<telegram_api::RichText>> &&rich_text_ptrs,
                                const std::unordered_map<int64, FileId> &documents);

RichText get_rich_text(tl_object_ptr<telegram_api::RichText> &&rich_text_ptr,
                       const std::unordered_map<int64, FileId> &documents) {
  CHECK(rich_text_ptr != nullptr);

  RichText result;
  switch (rich_text_ptr->get_id()) {
    case telegram_api::textEmpty::ID:
      break;
    case telegram_api::textPlain::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textPlain>(rich_text_ptr);
      result.content = std::move(rich_text->text_);
      break;
    }
    case telegram_api::textBold::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textBold>(rich_text_ptr);
      result.type = RichText::Type::Bold;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textItalic::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textItalic>(rich_text_ptr);
      result.type = RichText::Type::Italic;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textUnderline::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textUnderline>(rich_text_ptr);
      result.type = RichText::Type::Underline;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textStrike::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textStrike>(rich_text_ptr);
      result.type = RichText::Type::Strikethrough;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textFixed::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textFixed>(rich_text_ptr);
      result.type = RichText::Type::Fixed;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textUrl::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textUrl>(rich_text_ptr);
      result.type = RichText::Type::Url;
      result.content = std::move(rich_text->url_);
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      result.web_page_id = WebPageId(rich_text->webpage_id_);
      break;
    }
    case telegram_api::textEmail::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textEmail>(rich_text_ptr);
      result.type = RichText::Type::EmailAddress;
      result.content = std::move(rich_text->email_);
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textConcat::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textConcat>(rich_text_ptr);
      result.type = RichText::Type::Concatenation;
      result.texts = get_rich_texts(std::move(rich_text->texts_), documents);
      break;
    }
    case telegram_api::textSubscript::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textSubscript>(rich_text_ptr);
      result.type = RichText::Type::Subscript;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textSuperscript::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textSuperscript>(rich_text_ptr);
      result.type = RichText::Type::Superscript;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textMarked::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textMarked>(rich_text_ptr);
      result.type = RichText::Type::Marked;
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textPhone::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textPhone>(rich_text_ptr);
      result.type = RichText::Type::PhoneNumber;
      result.content = std::move(rich_text->phone_);
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    case telegram_api::textImage::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textImage>(rich_text_ptr);
      auto it = documents.find(rich_text->document_id_);
      if (it != documents.end()) {
        result.type = RichText::Type::Icon;
        result.document_file_id = it->second;
        Dimensions dimensions = get_dimensions(rich_text->w_, rich_text->h_);
        result.content = PSTRING() << (dimensions.width * static_cast<uint32>(65536) + dimensions.height);
      } else {
        LOG(ERROR) << "Can't find document " << rich_text->document_id_;
      }
      break;
    }
    case telegram_api::textAnchor::ID: {
      auto rich_text = move_tl_object_as<telegram_api::textAnchor>(rich_text_ptr);
      result.type = RichText::Type::Anchor;
      result.content = std::move(rich_text->name_);
      result.texts.push_back(get_rich_text(std::move(rich_text->text_), documents));
      break;
    }
    default:
      UNREACHABLE();
  }
  return result;
}

vector<RichText> get_rich_texts(vector<tl_object_ptr<telegram_api::RichText>> &&rich_text_ptrs,
                                const std::unordered_map<int64, FileId> &documents) {
  return transform(std::move(rich_text_ptrs), [&documents](tl_object_ptr<telegram_api::RichText> &&rich_text) {
    return get_rich_text(std::move(rich_text), documents);
  });
}

WebPageBlockCaption get_page_block_caption(tl_object_ptr<telegram_api::pageCaption> &&page_caption,
                                           const std::unordered_map<int64, FileId> &documents) {
  CHECK(page_caption != nullptr);
  WebPageBlockCaption result;
  result.text = get_rich_text(std::move(page_caption->text_), documents);
  result.credit = get_rich_text(std::move(page_caption->credit_), documents);
  return result;
}

unique_ptr<WebPageBlock> get_web_page_block(Td *td, tl_object_ptr<telegram_api::PageBlock> page_block_ptr,
                                            const std::unordered_map<int64, FileId> &animations,
                                            const std::unordered_map<int64, FileId> &audios,
                                            const std::unordered_map<int64, FileId> &documents,
                                            const std::unordered_map<int64, Photo> &photos,
                                            const std::unordered_map<int64, FileId> &videos,
                                            const std::unordered_map<int64, FileId> &voice_notes) {
  CHECK(page_block_ptr != nullptr);
  switch (page_block_ptr->get_id()) {
    case telegram_api::pageBlockUnsupported::ID:
      return nullptr;
    case telegram_api::pageBlockTitle::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockTitle>(page_block_ptr);
      return make_unique<WebPageBlockTitle>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockSubtitle::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockSubtitle>(page_block_ptr);
      return make_unique<WebPageBlockSubtitle>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockAuthorDate::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockAuthorDate>(page_block_ptr);
      return make_unique<WebPageBlockAuthorDate>(get_rich_text(std::move(page_block->author_), documents),
                                                 page_block->published_date_);
    }
    case telegram_api::pageBlockHeader::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockHeader>(page_block_ptr);
      return make_unique<WebPageBlockHeader>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockSubheader::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockSubheader>(page_block_ptr);
      return make_unique<WebPageBlockSubheader>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockKicker::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockKicker>(page_block_ptr);
      return make_unique<WebPageBlockKicker>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockParagraph::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockParagraph>(page_block_ptr);
      return make_unique<WebPageBlockParagraph>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockPreformatted::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockPreformatted>(page_block_ptr);
      return td::make_unique<WebPageBlockPreformatted>(get_rich_text(std::move(page_block->text_), documents),
                                                       std::move(page_block->language_));
    }
    case telegram_api::pageBlockFooter::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockFooter>(page_block_ptr);
      return make_unique<WebPageBlockFooter>(get_rich_text(std::move(page_block->text_), documents));
    }
    case telegram_api::pageBlockDivider::ID:
      return make_unique<WebPageBlockDivider>();
    case telegram_api::pageBlockAnchor::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockAnchor>(page_block_ptr);
      return td::make_unique<WebPageBlockAnchor>(std::move(page_block->name_));
    }
    case telegram_api::pageBlockList::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockList>(page_block_ptr);
      return td::make_unique<WebPageBlockList>(transform(std::move(page_block->items_), [&](auto &&list_item_ptr) {
        WebPageBlockList::Item item;
        CHECK(list_item_ptr != nullptr);
        switch (list_item_ptr->get_id()) {
          case telegram_api::pageListItemText::ID: {
            auto list_item = telegram_api::move_object_as<telegram_api::pageListItemText>(list_item_ptr);
            item.page_blocks.push_back(
                make_unique<WebPageBlockParagraph>(get_rich_text(std::move(list_item->text_), documents)));
            break;
          }
          case telegram_api::pageListItemBlocks::ID: {
            auto list_item = telegram_api::move_object_as<telegram_api::pageListItemBlocks>(list_item_ptr);
            item.page_blocks = get_web_page_blocks(td, std::move(list_item->blocks_), animations, audios, documents,
                                                   photos, videos, voice_notes);
            break;
          }
        }
        if (item.page_blocks.empty()) {
          item.page_blocks.push_back(make_unique<WebPageBlockParagraph>(RichText()));
        }
        return item;
      }));
    }
    case telegram_api::pageBlockOrderedList::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockOrderedList>(page_block_ptr);
      int32 current_label = 0;
      return td::make_unique<WebPageBlockList>(transform(std::move(page_block->items_), [&](auto &&list_item_ptr) {
        WebPageBlockList::Item item;
        CHECK(list_item_ptr != nullptr);
        switch (list_item_ptr->get_id()) {
          case telegram_api::pageListOrderedItemText::ID: {
            auto list_item = telegram_api::move_object_as<telegram_api::pageListOrderedItemText>(list_item_ptr);
            item.label = std::move(list_item->num_);
            item.page_blocks.push_back(
                make_unique<WebPageBlockParagraph>(get_rich_text(std::move(list_item->text_), documents)));
            break;
          }
          case telegram_api::pageListOrderedItemBlocks::ID: {
            auto list_item = telegram_api::move_object_as<telegram_api::pageListOrderedItemBlocks>(list_item_ptr);
            item.label = std::move(list_item->num_);
            item.page_blocks = get_web_page_blocks(td, std::move(list_item->blocks_), animations, audios, documents,
                                                   photos, videos, voice_notes);
            break;
          }
        }
        if (item.page_blocks.empty()) {
          item.page_blocks.push_back(make_unique<WebPageBlockParagraph>(RichText()));
        }
        ++current_label;
        if (item.label.empty()) {
          item.label = PSTRING() << current_label << '.';
        } else {
          item.label += '.';
        }
        return item;
      }));
    }
    case telegram_api::pageBlockBlockquote::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockBlockquote>(page_block_ptr);
      return make_unique<WebPageBlockBlockQuote>(get_rich_text(std::move(page_block->text_), documents),
                                                 get_rich_text(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockPullquote::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockPullquote>(page_block_ptr);
      return make_unique<WebPageBlockPullQuote>(get_rich_text(std::move(page_block->text_), documents),
                                                get_rich_text(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockPhoto::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockPhoto>(page_block_ptr);
      auto it = photos.find(page_block->photo_id_);
      Photo photo;
      if (it == photos.end()) {
        photo.id = -2;
      } else {
        photo = it->second;
      }
      string url;
      WebPageId web_page_id;
      if ((page_block->flags_ & telegram_api::pageBlockPhoto::URL_MASK) != 0) {
        url = std::move(page_block->url_);
        web_page_id = WebPageId(page_block->webpage_id_);
      }
      return td::make_unique<WebPageBlockPhoto>(std::move(photo),
                                                get_page_block_caption(std::move(page_block->caption_), documents),
                                                std::move(url), web_page_id);
    }
    case telegram_api::pageBlockVideo::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockVideo>(page_block_ptr);
      bool need_autoplay = (page_block->flags_ & telegram_api::pageBlockVideo::AUTOPLAY_MASK) != 0;
      bool is_looped = (page_block->flags_ & telegram_api::pageBlockVideo::LOOP_MASK) != 0;
      auto animations_it = animations.find(page_block->video_id_);
      if (animations_it != animations.end()) {
        LOG_IF(ERROR, !is_looped) << "Receive non-looped animation";
        return make_unique<WebPageBlockAnimation>(
            animations_it->second, get_page_block_caption(std::move(page_block->caption_), documents), need_autoplay);
      }

      auto it = videos.find(page_block->video_id_);
      FileId video_file_id;
      if (it != videos.end()) {
        video_file_id = it->second;
      }
      return make_unique<WebPageBlockVideo>(
          video_file_id, get_page_block_caption(std::move(page_block->caption_), documents), need_autoplay, is_looped);
    }
    case telegram_api::pageBlockCover::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockCover>(page_block_ptr);
      auto cover = get_web_page_block(td, std::move(page_block->cover_), animations, audios, documents, photos, videos,
                                      voice_notes);
      if (cover == nullptr) {
        return nullptr;
      }
      return make_unique<WebPageBlockCover>(std::move(cover));
    }
    case telegram_api::pageBlockEmbed::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockEmbed>(page_block_ptr);
      bool is_full_width = (page_block->flags_ & telegram_api::pageBlockEmbed::FULL_WIDTH_MASK) != 0;
      bool allow_scrolling = (page_block->flags_ & telegram_api::pageBlockEmbed::ALLOW_SCROLLING_MASK) != 0;
      bool has_dimensions = (page_block->flags_ & telegram_api::pageBlockEmbed::W_MASK) != 0;
      auto it = (page_block->flags_ & telegram_api::pageBlockEmbed::POSTER_PHOTO_ID_MASK) != 0
                    ? photos.find(page_block->poster_photo_id_)
                    : photos.end();
      Photo poster_photo;
      if (it == photos.end()) {
        poster_photo.id = -2;
      } else {
        poster_photo = it->second;
      }
      Dimensions dimensions;
      if (has_dimensions) {
        dimensions = get_dimensions(page_block->w_, page_block->h_);
      }
      return td::make_unique<WebPageBlockEmbedded>(
          std::move(page_block->url_), std::move(page_block->html_), std::move(poster_photo), dimensions,
          get_page_block_caption(std::move(page_block->caption_), documents), is_full_width, allow_scrolling);
    }
    case telegram_api::pageBlockEmbedPost::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockEmbedPost>(page_block_ptr);
      auto it = photos.find(page_block->author_photo_id_);
      Photo author_photo;
      if (it == photos.end()) {
        author_photo.id = -2;
      } else {
        author_photo = it->second;
      }
      return td::make_unique<WebPageBlockEmbeddedPost>(
          std::move(page_block->url_), std::move(page_block->author_), std::move(author_photo), page_block->date_,
          get_web_page_blocks(td, std::move(page_block->blocks_), animations, audios, documents, photos, videos,
                              voice_notes),
          get_page_block_caption(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockCollage::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockCollage>(page_block_ptr);
      return td::make_unique<WebPageBlockCollage>(get_web_page_blocks(td, std::move(page_block->items_), animations,
                                                                      audios, documents, photos, videos, voice_notes),
                                                  get_page_block_caption(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockSlideshow::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockSlideshow>(page_block_ptr);
      return td::make_unique<WebPageBlockSlideshow>(get_web_page_blocks(td, std::move(page_block->items_), animations,
                                                                        audios, documents, photos, videos, voice_notes),
                                                    get_page_block_caption(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockChannel::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockChannel>(page_block_ptr);
      CHECK(page_block->channel_ != nullptr);
      if (page_block->channel_->get_id() == telegram_api::channel::ID) {
        auto channel = static_cast<telegram_api::channel *>(page_block->channel_.get());
        ChannelId channel_id(channel->id_);
        if (!channel_id.is_valid()) {
          LOG(ERROR) << "Receive invalid " << channel_id;
          return nullptr;
        }

        if (td->contacts_manager_->have_channel_force(channel_id)) {
          td->contacts_manager_->on_get_chat(std::move(page_block->channel_), "pageBlockChannel");
          LOG(INFO) << "Receive known min " << channel_id;
          return td::make_unique<WebPageBlockChatLink>(td->contacts_manager_->get_channel_title(channel_id),
                                                       *td->contacts_manager_->get_channel_dialog_photo(channel_id),
                                                       td->contacts_manager_->get_channel_username(channel_id));
        } else {
          bool has_access_hash = (channel->flags_ & telegram_api::channel::ACCESS_HASH_MASK) != 0;
          return td::make_unique<WebPageBlockChatLink>(
              std::move(channel->title_),
              get_dialog_photo(td->file_manager_.get(), DialogId(channel_id),
                               has_access_hash ? channel->access_hash_ : 0, std::move(channel->photo_)),
              std::move(channel->username_));
        }
      } else {
        LOG(ERROR) << "Receive wrong channel " << to_string(page_block->channel_);
        return nullptr;
      }
    }
    case telegram_api::pageBlockAudio::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockAudio>(page_block_ptr);
      auto voice_note_it = voice_notes.find(page_block->audio_id_);
      if (voice_note_it != voice_notes.end()) {
        return make_unique<WebPageBlockVoiceNote>(voice_note_it->second,
                                                  get_page_block_caption(std::move(page_block->caption_), documents));
      }

      auto it = audios.find(page_block->audio_id_);
      FileId audio_file_id;
      if (it != audios.end()) {
        audio_file_id = it->second;
      }
      return make_unique<WebPageBlockAudio>(audio_file_id,
                                            get_page_block_caption(std::move(page_block->caption_), documents));
    }
    case telegram_api::pageBlockTable::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockTable>(page_block_ptr);
      auto is_bordered = (page_block->flags_ & telegram_api::pageBlockTable::BORDERED_MASK) != 0;
      auto is_striped = (page_block->flags_ & telegram_api::pageBlockTable::STRIPED_MASK) != 0;
      auto cells = transform(std::move(page_block->rows_), [&](tl_object_ptr<telegram_api::pageTableRow> &&row) {
        return transform(std::move(row->cells_), [&](tl_object_ptr<telegram_api::pageTableCell> &&table_cell) {
          WebPageBlockTableCell cell;
          auto flags = table_cell->flags_;
          cell.is_header = (flags & telegram_api::pageTableCell::HEADER_MASK) != 0;
          cell.align_center = (flags & telegram_api::pageTableCell::ALIGN_CENTER_MASK) != 0;
          if (!cell.align_center) {
            cell.align_right = (flags & telegram_api::pageTableCell::ALIGN_RIGHT_MASK) != 0;
            if (!cell.align_right) {
              cell.align_left = true;
            }
          }
          cell.valign_middle = (flags & telegram_api::pageTableCell::VALIGN_MIDDLE_MASK) != 0;
          if (!cell.valign_middle) {
            cell.valign_bottom = (flags & telegram_api::pageTableCell::VALIGN_BOTTOM_MASK) != 0;
            if (!cell.valign_bottom) {
              cell.valign_top = true;
            }
          }
          if (table_cell->text_ != nullptr) {
            cell.text = get_rich_text(std::move(table_cell->text_), documents);
          }
          if ((flags & telegram_api::pageTableCell::COLSPAN_MASK) != 0) {
            cell.colspan = table_cell->colspan_;
          }
          if ((flags & telegram_api::pageTableCell::ROWSPAN_MASK) != 0) {
            cell.rowspan = table_cell->rowspan_;
          }
          return cell;
        });
      });
      return td::make_unique<WebPageBlockTable>(get_rich_text(std::move(page_block->title_), documents),
                                                std::move(cells), is_bordered, is_striped);
    }
    case telegram_api::pageBlockDetails::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockDetails>(page_block_ptr);
      auto is_open = (page_block->flags_ & telegram_api::pageBlockDetails::OPEN_MASK) != 0;
      return td::make_unique<WebPageBlockDetails>(get_rich_text(std::move(page_block->title_), documents),
                                                  get_web_page_blocks(td, std::move(page_block->blocks_), animations,
                                                                      audios, documents, photos, videos, voice_notes),
                                                  is_open);
    }
    case telegram_api::pageBlockRelatedArticles::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockRelatedArticles>(page_block_ptr);
      auto articles = transform(
          std::move(page_block->articles_), [&](tl_object_ptr<telegram_api::pageRelatedArticle> &&related_article) {
            RelatedArticle article;
            article.url = std::move(related_article->url_);
            article.web_page_id = WebPageId(related_article->webpage_id_);
            article.title = std::move(related_article->title_);
            article.description = std::move(related_article->description_);
            auto it = (related_article->flags_ & telegram_api::pageRelatedArticle::PHOTO_ID_MASK) != 0
                          ? photos.find(related_article->photo_id_)
                          : photos.end();
            if (it == photos.end()) {
              article.photo.id = -2;
            } else {
              article.photo = it->second;
            }
            article.author = std::move(related_article->author_);
            if ((related_article->flags_ & telegram_api::pageRelatedArticle::PUBLISHED_DATE_MASK) != 0) {
              article.published_date = related_article->published_date_;
            }
            return article;
          });
      return td::make_unique<WebPageBlockRelatedArticles>(get_rich_text(std::move(page_block->title_), documents),
                                                          std::move(articles));
    }
    case telegram_api::pageBlockMap::ID: {
      auto page_block = move_tl_object_as<telegram_api::pageBlockMap>(page_block_ptr);
      Location location(std::move(page_block->geo_));
      auto zoom = page_block->zoom_;
      Dimensions dimensions = get_dimensions(page_block->w_, page_block->h_);
      if (location.empty()) {
        LOG(ERROR) << "Receive invalid map location";
        break;
      }
      if (zoom <= 0 || zoom > 30) {
        LOG(ERROR) << "Receive invalid map zoom " << zoom;
        break;
      }
      if (dimensions.width == 0) {
        LOG(ERROR) << "Receive invalid map dimensions " << page_block->w_ << " " << page_block->h_;
        break;
      }
      return make_unique<WebPageBlockMap>(std::move(location), zoom, dimensions,
                                          get_page_block_caption(std::move(page_block->caption_), documents));
    }
    default:
      UNREACHABLE();
  }
  return nullptr;
}

}  // namespace

template <class F>
void WebPageBlock::call_impl(Type type, const WebPageBlock *ptr, F &&f) {
  switch (type) {
    case Type::Title:
      return f(static_cast<const WebPageBlockTitle *>(ptr));
    case Type::Subtitle:
      return f(static_cast<const WebPageBlockSubtitle *>(ptr));
    case Type::AuthorDate:
      return f(static_cast<const WebPageBlockAuthorDate *>(ptr));
    case Type::Header:
      return f(static_cast<const WebPageBlockHeader *>(ptr));
    case Type::Subheader:
      return f(static_cast<const WebPageBlockSubheader *>(ptr));
    case Type::Kicker:
      return f(static_cast<const WebPageBlockKicker *>(ptr));
    case Type::Paragraph:
      return f(static_cast<const WebPageBlockParagraph *>(ptr));
    case Type::Preformatted:
      return f(static_cast<const WebPageBlockPreformatted *>(ptr));
    case Type::Footer:
      return f(static_cast<const WebPageBlockFooter *>(ptr));
    case Type::Divider:
      return f(static_cast<const WebPageBlockDivider *>(ptr));
    case Type::Anchor:
      return f(static_cast<const WebPageBlockAnchor *>(ptr));
    case Type::List:
      return f(static_cast<const WebPageBlockList *>(ptr));
    case Type::BlockQuote:
      return f(static_cast<const WebPageBlockBlockQuote *>(ptr));
    case Type::PullQuote:
      return f(static_cast<const WebPageBlockPullQuote *>(ptr));
    case Type::Animation:
      return f(static_cast<const WebPageBlockAnimation *>(ptr));
    case Type::Photo:
      return f(static_cast<const WebPageBlockPhoto *>(ptr));
    case Type::Video:
      return f(static_cast<const WebPageBlockVideo *>(ptr));
    case Type::Cover:
      return f(static_cast<const WebPageBlockCover *>(ptr));
    case Type::Embedded:
      return f(static_cast<const WebPageBlockEmbedded *>(ptr));
    case Type::EmbeddedPost:
      return f(static_cast<const WebPageBlockEmbeddedPost *>(ptr));
    case Type::Collage:
      return f(static_cast<const WebPageBlockCollage *>(ptr));
    case Type::Slideshow:
      return f(static_cast<const WebPageBlockSlideshow *>(ptr));
    case Type::ChatLink:
      return f(static_cast<const WebPageBlockChatLink *>(ptr));
    case Type::Audio:
      return f(static_cast<const WebPageBlockAudio *>(ptr));
    case Type::Table:
      return f(static_cast<const WebPageBlockTable *>(ptr));
    case Type::Details:
      return f(static_cast<const WebPageBlockDetails *>(ptr));
    case Type::RelatedArticles:
      return f(static_cast<const WebPageBlockRelatedArticles *>(ptr));
    case Type::Map:
      return f(static_cast<const WebPageBlockMap *>(ptr));
    case Type::VoiceNote:
      return f(static_cast<const WebPageBlockVoiceNote *>(ptr));
    default:
      UNREACHABLE();
  }
}

template <class StorerT>
void WebPageBlock::store(StorerT &storer) const {
  Type type = get_type();
  td::store(type, storer);
  call_impl(type, this, [&](const auto *object) { td::store(*object, storer); });
}

template <class ParserT>
unique_ptr<WebPageBlock> WebPageBlock::parse(ParserT &parser) {
  Type type;
  td::parse(type, parser);
  if (static_cast<int32>(type) < 0 || static_cast<int32>(type) >= static_cast<int32>(Type::Size)) {
    parser.set_error(PSTRING() << "Can't parse unknown BlockType " << static_cast<int32>(type));
    return nullptr;
  }
  unique_ptr<WebPageBlock> res;
  call_impl(type, nullptr, [&](const auto *ptr) {
    using ObjT = std::decay_t<decltype(*ptr)>;
    auto object = make_unique<ObjT>();
    td::parse(*object, parser);
    res = std::move(object);
  });
  return res;
}

template <class StorerT>
void store_web_page_block(const unique_ptr<WebPageBlock> &block, StorerT &storer) {
  block->store(storer);
}

template <class ParserT>
void parse_web_page_block(unique_ptr<WebPageBlock> &block, ParserT &parser) {
  block = WebPageBlock::parse(parser);
}

void store(const unique_ptr<WebPageBlock> &block, LogEventStorerCalcLength &storer) {
  store_web_page_block(block, storer);
}

void store(const unique_ptr<WebPageBlock> &block, LogEventStorerUnsafe &storer) {
  store_web_page_block(block, storer);
}

void parse(unique_ptr<WebPageBlock> &block, LogEventParser &parser) {
  parse_web_page_block(block, parser);
}

vector<unique_ptr<WebPageBlock>> get_web_page_blocks(
    Td *td, vector<tl_object_ptr<telegram_api::PageBlock>> page_block_ptrs,
    const std::unordered_map<int64, FileId> &animations, const std::unordered_map<int64, FileId> &audios,
    const std::unordered_map<int64, FileId> &documents, const std::unordered_map<int64, Photo> &photos,
    const std::unordered_map<int64, FileId> &videos, const std::unordered_map<int64, FileId> &voice_notes) {
  vector<unique_ptr<WebPageBlock>> result;
  result.reserve(page_block_ptrs.size());
  for (auto &page_block_ptr : page_block_ptrs) {
    auto page_block =
        get_web_page_block(td, std::move(page_block_ptr), animations, audios, documents, photos, videos, voice_notes);
    if (page_block != nullptr) {
      result.push_back(std::move(page_block));
    }
  }
  return result;
}

vector<td_api::object_ptr<td_api::PageBlock>> get_page_block_objects(
    const vector<unique_ptr<WebPageBlock>> &page_blocks, Td *td, Slice base_url) {
  GetWebPageBlockObjectContext context;
  context.td_ = td;
  context.base_url_ = base_url;
  auto blocks = get_page_block_objects(page_blocks, &context);
  if (context.anchors_.empty() || !context.has_anchor_urls_) {
    return blocks;
  }

  context.is_first_pass_ = false;
  context.anchors_.emplace(Slice(), nullptr);  // back to top
  return get_page_block_objects(page_blocks, &context);
}

}  // namespace td