Refactor place into table function

schema/layers/place.sql

@@ -1,53 +1,113 @@
 CREATE OR REPLACE VIEW place_z2 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
     WHERE  scalerank <= 0
 );
 
 CREATE OR REPLACE VIEW place_z3 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
     WHERE  scalerank <= 2
 );
 
 CREATE OR REPLACE VIEW place_z4 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
     WHERE  scalerank <= 5
 );
 
 CREATE OR REPLACE VIEW place_z5 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
     WHERE  scalerank <= 6
 );
 
 CREATE OR REPLACE VIEW place_z6 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
     WHERE  scalerank <= 7
 );
 
 CREATE OR REPLACE VIEW place_z7 AS (
-	SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
+    SELECT geom, name, 'settlement' AS class, 'city'::place AS rank, scalerank, pop_min AS population
     FROM ne_10m_populated_places
 );
 
 CREATE OR REPLACE VIEW place_z8 AS (
-	SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
+    SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
     WHERE rank IN ('city', 'town')
 );
 
 CREATE OR REPLACE VIEW place_z10 AS (
-	SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
+    SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
     WHERE rank IN ('city', 'town', 'village') OR class='subregion'
 );
 
 CREATE OR REPLACE VIEW place_z11 AS (
-	SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
+    SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
     WHERE class IN ('subregion', 'settlement')
 );
 
 CREATE OR REPLACE VIEW place_z13 AS (
-	SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
+    SELECT way AS geom, name, class::text, rank, NULL::integer AS scalerank, population FROM place_point
 );
+
+CREATE OR REPLACE FUNCTION layer_place(bbox geometry, zoom_level int, pixel_width numeric)
+RETURNS TABLE(geom geometry, name text, class text, rank text, scalerank int) AS $$
+    WITH zoom_levels AS (
+        SELECT * FROM place_z2
+        WHERE zoom_level = 2
+        UNION ALL
+        SELECT * FROM place_z3
+        WHERE zoom_level = 3
+        UNION ALL
+        SELECT * FROM place_z4
+        WHERE zoom_level = 4
+        UNION ALL
+        SELECT * FROM place_z5
+        WHERE zoom_level = 5
+        UNION ALL
+        SELECT * FROM place_z6
+        WHERE zoom_level = 6
+        UNION ALL
+        SELECT * FROM place_z7
+        WHERE zoom_level = 7
+        UNION ALL
+        SELECT * FROM place_z8
+        WHERE zoom_level BETWEEN 8 AND 9
+        UNION ALL
+        SELECT * FROM place_z10
+        WHERE zoom_level = 10
+        UNION ALL
+        SELECT * FROM place_z12
+        WHERE zoom_level BETWEEN 11 AND 12
+        UNION ALL
+        SELECT * FROM place_z13
+        WHERE zoom_level >= 13
+    ), ranked_places AS (
+        SELECT geom, name, class, rank, scalerank,
+        row_number() OVER (
+            PARTITION BY LabelGrid(geom, 150 * pixel_width)
+            ORDER BY scalerank ASC NULLS LAST,
+            CASE class
+            WHEN 'settlement' THEN 10
+            WHEN 'subregion' THEN 5
+            WHEN 'locality' THEN 2 ELSE 1
+            END DESC,
+            rank DESC,
+            population DESC NULLS LAST,
+            length(name) DESC
+        ) AS gridrank
+        FROM zoom_levels
+        WHERE geom && bbox
+    )
+    SELECT geom, name, class, rank::text, scalerank FROM ranked_places
+    WHERE
+        zoom_level <= 7 OR
+        (zoom_level = 8 AND gridrank <= 4) OR
+        (zoom_level = 9 AND gridrank <= 9) OR
+        (zoom_level = 10 AND gridrank <= 9) OR
+        (zoom_level = 11 AND gridrank <= 9) OR
+        (zoom_level = 12 AND gridrank <= 9) OR
+        zoom_level >= 13;
+$$ LANGUAGE SQL IMMUTABLE;