Port the show more books button

src/pyj/book_list/views.pyj

@@ -2,11 +2,16 @@
 # License: GPL v3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 from __python__ import hash_literals
 
-from dom import add_extra_css, clear, ensure_id
+import traceback
+
+from ajax import ajax_send
+from dom import add_extra_css, clear, ensure_id, set_css
 from elementmaker import E
 from gettext import gettext as _
+from modals import error_dialog
 from utils import conditional_timeout
 from session import get_interface_data
+from widgets import create_button, create_spinner
 
 from book_list.globals import get_session_data
 from book_list.cover_grid import cover_grid_css, create_item as create_cover_grid_item, init as init_cover_grid, append_item as cover_grid_append_item
@@ -24,7 +29,7 @@ add_extra_css(def():
 )
 
 book_list_data = {
-    'container_id': None, 'shown_book_ids': set(), 'is_fetching': False, 'mode': None,
+    'container_id': None, 'shown_book_ids': set(), 'mode': None, 'fetching_more_books': None,
 }
 
 
@@ -71,14 +76,81 @@ def apply_view_mode(mode=DEFAULT_MODE):
     render_ids()
 
 
+def update_fetching_status():
+    more = document.getElementById(book_list_data.container_id).lastChild
+    if book_list_data.fetching_more_books:
+        more.firstChild.style.display = 'none'
+        more.lastChild.style.display = 'block'
+    elif library_data.search_result.total_num > book_list_data.shown_book_ids.length:
+        more.firstChild.style.display = 'block'
+        more.lastChild.style.display = 'none'
+    else:
+        more.firstChild.style.display = 'none'
+        more.lastChild.style.display = 'none'
+
+
+def abort_get_more_books(no_update):
+    if book_list_data.fetching_more_books:
+        book_list_data.fetching_more_books.abort()
+        book_list_data.fetching_more_books = None
+        if not no_update:
+            update_fetching_status()
+
+
+def got_more_books(end_type, xhr, event):
+    if book_list_data.fetching_more_books is not xhr:
+        return  # Fetching was aborted
+    book_list_data.fetching_more_books = None
+    update_fetching_status()
+    if end_type is 'load':
+        try:
+            data = JSON.parse(xhr.responseText)
+            for key in data.metadata:
+                library_data.metadata[key] = data.metadata[key]
+            if not data.search_result.book_ids:
+                raise Exception('No books ids object in search result from server')
+            library_data.search_result = data.search_result
+            render_ids(data.search_result.book_ids)
+        except Exception:
+            error_dialog(_('Could not get more books'), _('Server returned an invalid response'), traceback.format_exc())
+    elif end_type is not 'abort':
+        error_dialog(_('Could not get more books'), xhr.error_html)
+
+
+def get_more_books():
+    data = {'offset':book_list_data.shown_book_ids.length}
+    for key in 'query', 'sort', 'sort_order':
+        data[key] = library_data.search_result[key]
+    book_list_data.fetching_more_books = ajax_send(
+        'interface-data/more-books', data, got_more_books,
+        query={'library_id':current_library_id()}
+    )
+    update_fetching_status()
+
+
+def create_more_button(more):
+    more.appendChild(create_button(
+        _('Show more books'), 'cloud-download', get_more_books
+    ))
+    more.lastChild.setAttribute('rel', 'next')
+    set_css(more.firstChild, display='block', margin_left='auto', margin_right='auto')
+    set_css(more, font_size='1.5rem', padding_top='1.5rem', margin_bottom='1.5rem', text_align='center', display='flex')
+    more.appendChild(E.div(
+        create_spinner(), '\xa0' + _('Fetching metadata for more books, please wait') + '…',
+        style='margin-left:auto; margin-right:auto; display:none')
+    )
+    update_fetching_status()
+
+
 def create_books_list(container):
     book_list_data.container_id = ensure_id(container)
     book_list_data.shown_book_ids = set()
-    book_list_data.is_fetching = False
     book_list_data.mode = None
+    abort_get_more_books(True)
     container.appendChild(E.div(style='display:none'))
     container.appendChild(E.div()), container.appendChild(E.div())
     apply_view_mode(get_session_data().get('view_mode'))
+    create_more_button(container.lastChild)
 
 
 def check_for_books_loaded():