Next free slot algorithm now in TT² form

templates/content-index.tpl.html: Now contains TT² code and an in-built
    query to determine the next free slot. No need for an external
    query. Old code that used to use this has been deleted.

templates/queries-index-mysql.tpl.html,
templates/queries-index-sqlite.tpl.html: Old queries called
    'query_next_available_episode' removed since no longer needed.

templates/content-index.tpl.html

@@ -30,13 +30,22 @@
     </header>
 	<!--% days_till_next_episode = 0 %-->
 	<!--% USE DBI(constants.driver, constants.user, constants.password) %-->
-	<!--% FOREACH next_available_episode_result IN DBI.query(query_next_available_episode) %-->
-	<!--% days_till_next_episode = next_available_episode_result.delta_days %-->
-	<!--% END %-->
 	<!--% 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 %-->
+	<!--% 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() %-->
+	<!--% days_till_next_episode = calc.Delta_Days(now.0,now.1,now.2,slot_date.0,slot_date.1,slot_date.2) %-->
+
 	<!--% delta = date.calc.N_Delta_YMD(2005,9,19, date.format(date.now, '%Y'),date.format(date.now, '%m'),date.format(date.now, '%d')) %-->
-	<p>We started producing shows as <a href="<!--% absolute_path(baseurl) %-->eps/index.html#twat_episodes"><em>Today with a Techie</em></a> on 2005-09-19, <!--% delta.0 %--> years, <!--% delta.1 %--> months, <!--% delta.2 %--> days ago. our shows are produced by <a href="<!--% absolute_path(baseurl) %-->correspondents/index.html">listeners</a> like you and can be on any <a href="<!--% absolute_path(baseurl) %-->eps/index.html">topic</a> that <strong>"are of interest to <a href="https://en.wikipedia.org/wiki/hacker_(hobbyist)">hackers</a>"</strong>. If you listen to HPR then please consider contributing one show a year. if you <a href="<!--% absolute_url(baseurl) %-->about.html#so_you_want_to_record_a_podcast">record</a> your show now it could be <a href="<!--% hub_baseurl %-->calendar.php">released</a> in <strong><!--% days_till_next_episode %--></strong> days.</p>
+	<p>We started producing shows as <a href="<!--% absolute_path(baseurl) %-->eps/index.html#twat_episodes"><em>Today with a Techie</em></a> on 2005-09-19, <!--% delta.0 %--> years, <!--% delta.1 %--> months, <!--% delta.2 %--> days ago. Our shows are produced by <a href="<!--% absolute_path(baseurl) %-->correspondents/index.html">listeners</a> like you and can be on any <a href="<!--% absolute_path(baseurl) %-->eps/index.html">topics</a> that <strong>"are of interest to <a href="https://en.wikipedia.org/wiki/hacker_(hobbyist)">hackers</a>"</strong>. If you listen to HPR then please consider contributing one show a year. If you <a href="<!--% absolute_url(baseurl) %-->about.html#so_you_want_to_record_a_podcast">record</a> your show now it could be <a href="<!--% hub_baseurl %-->calendar.php">released</a> in <strong><!--% days_till_next_episode %--></strong> days.</p>
   </article>
   <!--% display_call_for_shows() %-->
   <hr>

templates/queries-index-mysql.tpl.html

@@ -1,33 +1,3 @@
-<!--% query_next_available_episode = '
-    WITH RECURSIVE
-    min_id AS (
-	SELECT max(id) AS start_id FROM eps WHERE date <= NOW()
-    ),
-    max_id AS (
-	SELECT max(id) AS end_id FROM eps
-    ),
-    cnt(x) AS (
-	SELECT start_id from min_id
-	UNION ALL
-	SELECT x+1 FROM cnt
-	WHERE x+1 <= (SELECT end_id FROM max_id)
-    ),
-    first_empty AS (
-	SELECT
-	    cnt.x AS id
-	FROM cnt
-	LEFT JOIN eps e ON cnt.x = e.id
-	WHERE e.id IS NULL
-    )
-    SELECT
-	fe.id as next_id,
-	(SELECT DATE(ADDDATE(e2.date,1)) from eps e2 where e2.id = fe.id-1) as next_date,
-	DATEDIFF((SELECT ADDDATE(e3.date,1) from eps e3 where e3.id = fe.id-1),now()) AS delta_days
-    FROM first_empty AS fe
-    LEFT JOIN eps e1 ON fe.id = e1.id
-    LIMIT 1
-'
-%-->
 <!--% query_latest_episodes = '
 	WITH comment_tallies AS (
 		SELECT

templates/queries-index-sqlite.tpl.html

@@ -1,33 +1,3 @@
-<!--% query_next_available_episode = '
-    WITH RECURSIVE
-    min_id AS (
-	SELECT max(id) AS start_id FROM eps WHERE date <= date(\'now\')
-    ),
-    max_id AS (
-	SELECT max(id) AS end_id FROM eps
-    ),
-    cnt(x) AS (
-	SELECT start_id from min_id
-	UNION ALL
-	SELECT x+1 FROM cnt
-	WHERE x+1 <= (SELECT end_id FROM max_id)
-    ),
-    first_empty AS (
-	SELECT
-	    cnt.x AS id
-	FROM cnt
-	LEFT JOIN eps e ON cnt.x = e.id
-	WHERE e.id IS NULL
-    )
-    SELECT
-	fe.id as next_id,
-	(SELECT date(eps.date,\'+1 day\') from eps where id = fe.id-1) as next_date,
-	printf(\'%i\',abs(julianday((SELECT date(eps.date,\'+1 day\') from eps where id = fe.id-1)) - julianday(\'now\') + 1)) AS delta_days
-    FROM first_empty AS fe
-    LEFT JOIN eps e ON fe.id = e.id
-    LIMIT 1
-'
-%-->
 <!--% query_latest_episodes = '
 	WITH comment_tallies AS (
 		SELECT