From e5b5aac10475a8a6010672b91f159fd5904c42f3 Mon Sep 17 00:00:00 2001
From: Dave Morriss <Dave.Morriss@gmail.com>
Date: Fri, 17 Nov 2023 18:23:22 +0000
Subject: [PATCH] A further fix to the free slot algorithm
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templates/content-index.tpl.html: the `TT²` algorithm can be simplified
    because the new query returns less. We get the date of the show
    before the free slot, and can increment it differently depending on
    whether the previous show is on a Friday or not - catering for
    weekends in other words!

templates/queries-index-mysql.tpl.html,
templates/queries-index-sqlite.tpl.html: using a 'find unused index
    numbers' query available in many places on the Internet, but
    modified to return the id number and date for the show *before* the
    next free slot.
---
 templates/content-index.tpl.html        |  9 ++-------
 templates/queries-index-mysql.tpl.html  | 12 ++++++++++++
 templates/queries-index-sqlite.tpl.html | 12 ++++++++++++
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/templates/content-index.tpl.html b/templates/content-index.tpl.html
index ae4ea18..1c9b563 100644
--- a/templates/content-index.tpl.html
+++ b/templates/content-index.tpl.html
@@ -32,13 +32,8 @@
 	<!--% USE DBI(constants.driver, constants.user, constants.password) %-->
 	<!--% USE date %-->
 	<!--% calc = date.calc %-->
-	<!--% episodes = DBI.query("SELECT id, date FROM eps WHERE date >= date('now') ORDER BY id").get_all() %-->
-	<!--% ind = episodes.0.id %-->
-	<!--% FOREACH ep IN episodes %-->
-	<!--%     LAST IF ep.id != ind %-->
-	<!--%     last_date = ep.date.split('-') %-->
-	<!--%     ind = ind+1 %-->
-	<!--% END %-->
+	<!--% episodes = DBI.query(query_next_available_episode).get_all() %-->
+	<!--% last_date = episodes.0.date.split('-') %-->
 	<!--% offset = (calc.Day_of_Week(last_date.0,last_date.1,last_date.2) == 5 ? 3 : 1) %-->
 	<!--% slot_date = calc.Add_Delta_Days(last_date.0,last_date.1,last_date.2,offset) %-->
 	<!--% now = calc.Today() %-->
diff --git a/templates/queries-index-mysql.tpl.html b/templates/queries-index-mysql.tpl.html
index f8b95c1..1f29958 100644
--- a/templates/queries-index-mysql.tpl.html
+++ b/templates/queries-index-mysql.tpl.html
@@ -1,3 +1,15 @@
+<!--% query_next_available_episode = '
+    SELECT id, date FROM eps e WHERE id = (
+        SELECT  id + 1 FROM eps mo
+            WHERE NOT EXISTS (
+		SELECT NULL
+		FROM   eps mi
+		WHERE  mi.id = mo.id + 1
+            )
+        ORDER BY id
+        LIMIT 1) - 1
+    '
+%-->
 <!--% query_latest_episodes = '
 	WITH comment_tallies AS (
 		SELECT
diff --git a/templates/queries-index-sqlite.tpl.html b/templates/queries-index-sqlite.tpl.html
index dd9afeb..70ea1b6 100644
--- a/templates/queries-index-sqlite.tpl.html
+++ b/templates/queries-index-sqlite.tpl.html
@@ -1,3 +1,15 @@
+<!--% query_next_available_episode = '
+    SELECT id, date FROM eps e WHERE id = (
+        SELECT  id + 1 FROM eps mo
+            WHERE NOT EXISTS (
+		SELECT NULL
+		FROM   eps mi
+		WHERE  mi.id = mo.id + 1
+            )
+        ORDER BY id
+        LIMIT 1) - 1
+    '
+%-->
 <!--% query_latest_episodes = '
 	WITH comment_tallies AS (
 		SELECT