Ensure metadata is loaded on the EM page

src/pyj/book_list/book_details.pyj

@@ -459,11 +459,16 @@ def add_top_bar_buttons(container_id):
         add_button(container, 'trash', action=delete_book, tooltip=_('Delete this book'))
         book_id = parse_url_params().book_id
         if book_id is '0':
-            add_button(container, 'random', def(): fetch_metadata(container_id, 0);)
+            add_button(container, 'random', def(): fetch_metadata(container_id, 0, proceed_after_succesful_fetch_metadata);)
         add_button(container, 'ellipsis-v', action=show_subsequent_panel.bind(None, 'more_actions'), tooltip=_('More actions'))
 
 
-def metadata_fetched(container_id, book_id, end_type, xhr, event):
+def proceed_after_succesful_fetch_metadata(container_id, book_id):
+    render_book(container_id, book_id)
+    add_top_bar_buttons(container_id)
+
+
+def metadata_fetched(container_id, book_id, proceed, end_type, xhr, event):
     nonlocal current_fetch
     if current_fetch is None or current_fetch is not xhr:
         return  # Fetching was aborted
@@ -481,8 +486,7 @@ def metadata_fetched(container_id, book_id, end_type, xhr, event):
         clear(c)
         book_id = int(data['id'])
         set_book_metadata(book_id, data)
-        render_book(container_id, book_id)
-        add_top_bar_buttons(container_id)
+        proceed(container_id, book_id)
     elif end_type is not 'abort':
         clear(c)
         c.appendChild(E.div(
@@ -492,14 +496,14 @@ def metadata_fetched(container_id, book_id, end_type, xhr, event):
         ))
         safe_set_inner_html(c.lastChild.lastChild, xhr.error_html)
 
-def fetch_metadata(container_id, book_id):
+def fetch_metadata(container_id, book_id, proceed):
     nonlocal current_fetch
     container = document.getElementById(container_id)
     if not container:
         return
     if current_fetch:
         current_fetch.abort()
-    current_fetch = ajax('interface-data/book-metadata/' + book_id, metadata_fetched.bind(None, container_id, book_id),
+    current_fetch = ajax('interface-data/book-metadata/' + book_id, metadata_fetched.bind(None, container_id, book_id, proceed),
                          query={'library_id':current_library_id(), 'vl':current_virtual_library()})
     current_fetch.send()
     container = container.lastChild
@@ -522,17 +526,10 @@ def create_book_details(container):
         render_book(container_id, current_book_id)
         add_top_bar_buttons(container_id)
     else:
-        fetch_metadata(container_id, current_book_id)
+        fetch_metadata(container_id, current_book_id, proceed_after_succesful_fetch_metadata)
 
 
-def check_for_books_loaded():
-    container = this
-    if load_status.loading:
-        conditional_timeout(container.id, 5, check_for_books_loaded)
-        return
-    container = container.lastChild
-    clear(container)
-    if not load_status.ok:
+def report_load_failure(container):
     err = E.div()
     safe_set_inner_html(err, load_status.error_html)
     container.appendChild(E.div(
@@ -544,6 +541,17 @@ def check_for_books_loaded():
             E.a(onclick=def(): home(replace=True);, href='javascript: void(0)', style='color: blue', _('Go back to the home page')))
         ),
     )
+
+
+def check_for_books_loaded():
+    container = this
+    if load_status.loading:
+        conditional_timeout(container.id, 5, check_for_books_loaded)
+        return
+    container = container.lastChild
+    clear(container)
+    if not load_status.ok:
+        report_load_failure(container)
         return
     create_book_details(container)
 

src/pyj/book_list/edit_metadata.pyj

@@ -2,11 +2,66 @@
 # License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 from __python__ import bound_methods, hash_literals
 
-from book_list.ui import set_panel_handler
+from elementmaker import E
+from gettext import gettext as _
+
+from book_list.book_details import no_book, report_load_failure, fetch_metadata
+from book_list.library_data import book_metadata, load_status
+from book_list.router import back
+from book_list.top_bar import create_top_bar
+from book_list.ui import set_panel_handler, show_panel
+from dom import clear
+from utils import conditional_timeout, parse_url_params
+
+current_book_id = None
+current_fetch = None
+CLASS_NAME = 'edit-metadata-panel'
+
+
+def proceed_after_succesful_fetch_metadata(container_id, book_id):
+    print(book_metadata(book_id))
+
+
+def create_edit_metadata(container):
+    q = parse_url_params()
+    current_book_id = q.book_id
+    if not current_book_id:
+        no_book(container)
+        return
+    current_book_id = int(current_book_id)
+    container_id = container.parentNode.id
+    if not book_metadata(current_book_id):
+        fetch_metadata(container_id, current_book_id, proceed_after_succesful_fetch_metadata)
+    else:
+        proceed_after_succesful_fetch_metadata(container_id, current_book_id)
+
+
+def check_for_books_loaded():
+    container = this
+    if load_status.loading:
+        conditional_timeout(container.id, 5, check_for_books_loaded)
+        return
+    container = container.lastChild
+    clear(container)
+    if not load_status.ok:
+        report_load_failure(container)
+        return
+    create_edit_metadata(container)
 
 
 def init(container_id):
-    pass
+    nonlocal current_book_id
+    container = document.getElementById(container_id)
+    container.appendChild(E.div(class_=CLASS_NAME))
+    container.lastChild.appendChild(E.div(_('Loading books from the calibre library, please wait...'), style='margin: 1ex 1em'))
+    conditional_timeout(container_id, 5, check_for_books_loaded)
+    q = parse_url_params()
+    current_book_id = int(q.book_id or 0)
+    mi = book_metadata(current_book_id)
+    if not mi or not container:
+        show_panel('book_details', query=q, replace=True)
+        return
+    create_top_bar(container, title=_('Edit metadata for {}').format(mi.title), action=back, icon='close')
 
 
 set_panel_handler('edit_metadata', init)