discourse/script/import_scripts/vanilla_body_parser.rb

# frozen_string_literal: true

class VanillaBodyParser
  def self.configure(lookup:, uploader:, host:, uploads_path:)
    @@lookup = lookup
    @@uploader = uploader
    @@host = host
    @@uploads_path = uploads_path
  end

  def initialize(row, user_id)
    @row = row
    @user_id = user_id
  end

  def parse
    return clean_up(@row["Body"]) unless rich?

    full_text = json.each_with_index.map(&method(:parse_fragment)).join("")

    normalize full_text
  end

  private

  def clean_up(text)
    # <pre class="CodeBlock">...</pre>
    text = text.gsub(%r{\<pre class="CodeBlock"\>(.*?)\</pre\>}im) { "\n```\n#{$1}\n```\n" }
    # <pre>...</pre>
    text = text.gsub(%r{\<pre\>(.*?)\</pre\>}im) { "\n```\n#{$1}\n```\n" }
    # <code></code>
    text = text.gsub("\<code\>\</code\>", "").gsub(%r{\<code\>(.*?)\</code\>}im) { "#{$1}" }
    # <div class="Quote">...</div>
    text = text.gsub(%r{\<div class="Quote"\>(.*?)\</div\>}im) { "\n[quote]\n#{$1}\n[/quote]\n" }
    # [code], [quote]
    text =
      text
        .gsub(%r{\[/?code\]}i, "\n```\n")
        .gsub(/\[quote.*?\]/i, "\n" + '\0' + "\n")
        .gsub(%r{\[/quote\]}i, "\n" + '\0' + "\n")

    text
      .gsub(%r{</?font[^>]*>}, "")
      .gsub(%r{</?span[^>]*>}, "")
      .gsub(%r{</?div[^>]*>}, "")
      .gsub(/^ +/, "")
      .gsub(/ +/, " ")
  end

  def rich?
    @row["Format"].casecmp?("Rich")
  end

  def json
    return nil unless rich?
    @json ||= JSON.parse(@row["Body"]).map(&:deep_symbolize_keys)
  end

  def parse_fragment(fragment, index)
    text =
      (
        if fragment.keys.one? && fragment[:insert].is_a?(String)
          fragment[:insert]
        else
          rich_parse(fragment)
        end
      )

    text = parse_code(text, fragment, index)
    text = parse_list(text, fragment, index)

    text
  end

  def rich_parse(fragment)
    insert = fragment[:insert]

    if insert.respond_to?(:dig) && insert.dig(:mention, :userID)
      return parse_mention(insert[:mention])
    end

    return parse_formatting(fragment) if fragment[:attributes]

    embed_type = insert.dig(:"embed-external", :data, :embedType)

    quoting = embed_type == "quote"
    return parse_quote(insert) if quoting

    embed = embed_type.in? %w[image link file]
    parse_embed(insert, embed_type) if embed
  end

  def parse_mention(mention)
    user = user_from_imported_id(mention[:userID])
    username = user&.username || mention[:name]
    "@#{username}"
  end

  def user_from_imported_id(imported_id)
    user_id = @@lookup.user_id_from_imported_user_id(imported_id)
    User.find(user_id) if user_id
  end

  def parse_formatting(fragment)
    insert = fragment[:insert]
    attributes = fragment[:attributes]

    text = fragment[:insert]

    text = "<a href=\"#{attributes[:link]}\">#{text}</a>" if attributes[:link]
    text = "<i>#{text}</i>" if attributes[:italic]
    text = "<b>#{text}</b>" if attributes[:bold]

    text
  end

  # In the Quill format used by Vanilla Forums, a line is rendered as `code`
  # when it's followed by a fragment with attributes: {'code-block': true}.
  def parse_code(text, fragment, index)
    next_fragment = next_fragment(index)

    next_code = next_fragment.dig(:attributes, :"code-block")
    if next_code
      previous_fragment = previous_fragment(index)
      previous_code = previous_fragment.dig(:attributes, :"code-block")

      if previous_code
        text = text.gsub(/\\n(.*?)\\n/) { "\n```\n#{$1}\n```\n" }
      else
        last_pos = text.rindex(/\n/)

        if last_pos
          array = [text[0..last_pos].strip, text[last_pos + 1..text.length].strip]
          text = array.join("\n```\n")
        else
          text = "\n```\n#{text}"
        end
      end
    end

    current_code = fragment.dig(:attributes, :"code-block")
    if current_code
      second_next_fragment = second_next_fragment(index)
      second_next_code = second_next_fragment.dig(:attributes, :"code-block")

      # if current is code and 2 after is not, prepend ```
      text = "\n```\n#{text}" unless second_next_code
    end

    text
  end

  def parse_list(text, fragment, index)
    next_fragment = next_fragment(index)

    next_list = next_fragment.dig(:attributes, :list, :type)
    if next_list
      # if next is list, prepend <li>
      text = "<li>" + text

      previous_fragment = previous_fragment(index)
      previous_list = previous_fragment.dig(:attributes, :list, :type)

      # if next is list and previous is not, prepend <ol> or <ul>
      list_tag = next_list == "ordered" ? "<ol>" : "<ul>"
      text = "\n#{list_tag}\n#{text}" unless previous_list
    end

    current_list = fragment.dig(:attributes, :list, :type)

    if current_list
      # if current is list prepend </li>
      tag_closings = "</li>"

      second_next_fragment = second_next_fragment(index)
      second_next_list = second_next_fragment.dig(:attributes, :list, :type)

      # if current is list and 2 after is not, prepend </ol>
      list_tag = current_list == "ordered" ? "</ol>" : "</ul>"
      tag_closings = "#{tag_closings}\n#{list_tag}" unless second_next_list

      text = tag_closings + text
    end

    text
  end

  def next_fragment(index)
    json[index + 1] || {}
  end

  def previous_fragment(index)
    json[index - 1] || {}
  end

  def second_next_fragment(index)
    json[index + 2] || {}
  end

  def parse_quote(insert)
    embed = insert.dig(:"embed-external", :data)

    import_post_id = "#{embed[:recordType]}##{embed[:recordID]}"
    topic = @@lookup.topic_lookup_from_imported_post_id(import_post_id)
    user = user_from_imported_id(embed.dig(:insertUser, :userID))

    quote_info =
      (
        if topic && user
          "=\"#{user.username}, post: #{topic[:post_number]}, topic: #{topic[:topic_id]}\""
        else
          ""
        end
      )

    "[quote#{quote_info}]\n#{embed[:body]}\n[/quote]\n\n" \
      ""
  end

  def parse_embed(insert, embed_type)
    embed = insert.dig(:"embed-external", :data)

    url = embed[:url]

    if %r{https?\://#{@@host}/uploads/.*}.match?(url)
      remote_path = url.scan(%r{uploads/(.*)})
      path = File.join(@@uploads_path, remote_path)

      upload = @@uploader.create_upload(@user_id, path, embed[:name])

      if upload&.persisted?
        return "\n" + @@uploader.html_for_upload(upload, embed[:name]) + "\n"
      else
        puts "Failed to upload #{path}"
        puts upload.errors.full_messages.join(", ") if upload
      end
    end

    if embed_type == "link"
      "\n[#{embed[:name]}](#{url})\n"
    elsif embed_type == "image"
      "\n<img src=\"#{url}\" alt=\"#{embed[:name]}\">\n"
    else
      "\n<a href=\"#{url}\">#{embed[:name]}</a>\n"
    end
  end

  def normalize(full_text)
    code_matcher = /```(.*\n)+```/
    code_block = full_text[code_matcher]
    full_text[code_matcher] = "{{{CODE_BLOCK}}}" if code_block
    full_text = double_new_lines(full_text)
    full_text["{{{CODE_BLOCK}}}"] = code_block if code_block
    full_text
  end

  def double_new_lines(text)
    text.split("\n").map(&:strip).map(&:presence).compact.join("\n\n")
  end
end