server, ics, pages: allow to generate ICS from modules

This adds the ability to generate an ICS file from a module ID, and to
filter it based on its groups.

To do this, you can enter a module ID on the frontpage.  Then, µCS will
fetch the timetable, then return a page where one can select the
group(s) they want to filter (this is enabled by the new
Ics.get_all_groups function).  Then, µCS is able to generate a link to
that calendar, not unlike with a single group ID.

Signed-off-by: Alban Gruin <alban at pa1ch dot fr>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/pages.ml b/src/pages.ml
index 2cb0aa4..feb2769 100644
--- a/src/pages.ml
+++ b/src/pages.ml
@@ -48,6 +48,11 @@ let main = common {|
           <input type="text" name="group" id="id_group" required />
           <input type="submit" value="Générer un ICS" />
         </form>
+        <form action="/filter" method="get">
+          <label for="id_module">ID du module</label>
+          <input type="text" name="module" id="id_module" required />
+          <input type="submit" value="Générer un ICS" />
+        </form>
       </section>
       <section>
         <p>
@@ -99,3 +104,18 @@ let link lnk =
         <a href="|} ^ lnk ^ {|">|} ^ lnk ^ {|</a>
       </section>
 |}
+
+let select module_id groups =
+  let options =
+    Seq.map (fun group -> "          <option>" ^ escape group ^ "</option>") groups
+    |> List.of_seq
+    |> String.concat "\n" in
+  common @@ {|
+      <form method="post" action="/lnk">
+        <select name="groups" multiple>
+|} ^ options ^ {|
+        </select>
+        <input type="hidden" name="module" value="|} ^ module_id ^ {|" />
+        <input type="submit" text="Valider" />
+      </form>
+|}