-- migrate:up
CREATE FUNCTION api.export_articles_zip (website_id UUID)
  RETURNS "*/*"
  AS $$
DECLARE
  _has_access BOOLEAN;
  _headers TEXT;
  _article RECORD;
  _markdown_dir TEXT := '/tmp/website-' || export_articles_zip.website_id;
BEGIN
  _has_access = internal.user_has_website_access (export_articles_zip.website_id, 20);

  SELECT
    FORMAT('[{ "Content-Type": "application/gzip" },'
    '{ "Content-Disposition": "attachment; filename=\"%s\"" }]',
    'archtika-export-articles-' || export_articles_zip.website_id || '.tar.gz') INTO _headers;
  PERFORM
    SET_CONFIG('response.headers', _headers, TRUE);

  EXECUTE FORMAT('COPY (SELECT '''') TO PROGRAM ''mkdir -p %s''', _markdown_dir || '/articles');

  FOR _article IN (
    SELECT a.id, a.website_id, a.slug, a.main_content
    FROM internal.article AS a
    WHERE a.website_id = export_articles_zip.website_id)
  LOOP
    EXECUTE FORMAT(
      'COPY (SELECT %L) TO ''%s''',
      _article.main_content,
      _markdown_dir || '/articles/' || _article.slug || '.md'
    );
  END LOOP;

  EXECUTE FORMAT('COPY (SELECT '''') TO PROGRAM ''tar -czf %s -C %s articles && rm %s''',
    _markdown_dir || '/export.tar.gz',
    _markdown_dir,
    _markdown_dir || '/articles/*.md'
  );

  RETURN pg_read_binary_file(_markdown_dir || '/export.tar.gz');
END;
$$
LANGUAGE plpgsql
SECURITY DEFINER;

GRANT EXECUTE ON FUNCTION api.export_articles_zip TO authenticated_user;

-- migrate:down
DROP FUNCTION api.export_articles_zip;