CREATE OR REPLACE FUNCTION highway_is_link(highway TEXT) RETURNS BOOLEAN AS $$
    SELECT highway LIKE '%_link';
$$ LANGUAGE SQL IMMUTABLE STRICT;


-- etldoc: layer_transportation[shape=record fillcolor=lightpink, style="rounded,filled",
-- etldoc:     label="<sql> layer_transportation |<z4> z4 |<z5> z5 |<z6> z6 |<z7> z7 |<z8> z8 |<z9> z9 |<z10> z10 |<z11> z11 |<z12> z12|<z13> z13|<z14_> z14+" ] ;
CREATE OR REPLACE FUNCTION layer_transportation(bbox geometry, zoom_level int)
RETURNS TABLE(osm_id bigint, geometry geometry, class text, subclass text,
ramp int, oneway int, brunnel TEXT, service TEXT, layer INT, level INT,
indoor INT, surface TEXT) AS $$
    SELECT
        osm_id, geometry,
        CASE
            WHEN NULLIF(highway, '') IS NOT NULL OR NULLIF(public_transport, '') IS NOT NULL THEN highway_class(highway, public_transport)
            WHEN NULLIF(railway, '') IS NOT NULL THEN railway_class(railway)
            WHEN NULLIF(aerialway, '') IS NOT NULL THEN aerialway
            WHEN NULLIF(shipway, '') IS NOT NULL THEN shipway
            WHEN NULLIF(man_made, '') IS NOT NULL THEN man_made
        END AS class,
        CASE
            WHEN railway IS NOT NULL THEN railway
            WHEN (highway IS NOT NULL OR public_transport IS NOT NULL)
                AND highway_class(highway, public_transport) = 'path'
                THEN COALESCE(NULLIF(public_transport, ''), highway)
            ELSE NULL
        END AS subclass,
        -- All links are considered as ramps as well
        CASE WHEN highway_is_link(highway) OR highway = 'steps'
             THEN 1 ELSE is_ramp::int END AS ramp,
        is_oneway::int AS oneway,
        brunnel(is_bridge, is_tunnel, is_ford) AS brunnel,
        NULLIF(service, '') AS service,
        NULLIF(layer, 0) AS layer,
        "level",
        CASE WHEN indoor=TRUE THEN 1 ELSE NULL END as indoor,
        NULLIF(surface, '') AS surface
    FROM (
        -- etldoc: osm_transportation_merge_linestring_gen7 -> layer_transportation:z4
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
	    NULL AS surface,
            z_order
        FROM osm_transportation_merge_linestring_gen7
        WHERE zoom_level = 4
        UNION ALL

        -- etldoc: osm_transportation_merge_linestring_gen6 -> layer_transportation:z5
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_transportation_merge_linestring_gen6
        WHERE zoom_level = 5
        UNION ALL

        -- etldoc: osm_transportation_merge_linestring_gen5 -> layer_transportation:z6
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_transportation_merge_linestring_gen5
        WHERE zoom_level = 6
        UNION ALL

        -- etldoc: osm_transportation_merge_linestring_gen4  ->  layer_transportation:z7
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_transportation_merge_linestring_gen4
        WHERE zoom_level = 7
        UNION ALL

        -- etldoc: osm_transportation_merge_linestring_gen3  ->  layer_transportation:z8
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_transportation_merge_linestring_gen3
        WHERE zoom_level = 8
        UNION ALL

        -- etldoc: osm_highway_linestring_gen2  ->  layer_transportation:z9
        -- etldoc: osm_highway_linestring_gen2  ->  layer_transportation:z10
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_highway_linestring_gen2
        WHERE zoom_level BETWEEN 9 AND 10
          AND st_length(geometry)>zres(11)
        UNION ALL

        -- etldoc: osm_highway_linestring_gen1  ->  layer_transportation:z11
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, NULL AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_highway_linestring_gen1
        WHERE zoom_level = 11
          AND st_length(geometry)>zres(12)
        UNION ALL

        -- etldoc: osm_highway_linestring       ->  layer_transportation:z12
        -- etldoc: osm_highway_linestring       ->  layer_transportation:z13
        -- etldoc: osm_highway_linestring       ->  layer_transportation:z14_
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, man_made,
            layer,
            CASE WHEN highway IN ('footway', 'steps') THEN "level"
                ELSE NULL::int
            END AS "level",
            CASE WHEN highway IN ('footway', 'steps') THEN indoor
                ELSE NULL::boolean
            END AS indoor,
            surface_value(surface) AS "surface",
            z_order
        FROM osm_highway_linestring
        WHERE NOT is_area AND (
            zoom_level = 12 AND (
                highway_class(highway, public_transport) NOT IN ('track', 'path', 'minor')
                OR highway IN ('unclassified', 'residential')
            ) AND man_made <> 'pier'
            OR zoom_level = 13
                AND (
                    highway_class(highway, public_transport) NOT IN ('track', 'path') AND man_made <> 'pier'
                OR
                    man_made = 'pier' AND NOT ST_IsClosed(geometry)
                )
            OR zoom_level >= 14
                AND (
                    man_made <> 'pier'
                OR
                    NOT ST_IsClosed(geometry)
                )
        )
        UNION ALL

        -- etldoc: osm_railway_linestring_gen5  ->  layer_transportation:z8
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            NULL::int AS layer, NULL::int AS level, NULL::boolean AS indoor,
	    NULL as surface, z_order
        FROM osm_railway_linestring_gen5
        WHERE zoom_level = 8
            AND railway='rail' AND service = '' and usage='main'
        UNION ALL

        -- etldoc: osm_railway_linestring_gen4  ->  layer_transportation:z9
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            NULL::boolean AS is_bridge, NULL::boolean AS is_tunnel,
            NULL::boolean AS is_ford,
            NULL::boolean AS is_ramp, NULL::int AS is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
	    NULL AS surface, z_order
        FROM osm_railway_linestring_gen4
        WHERE zoom_level = 9
            AND railway='rail' AND service = '' and usage='main'
        UNION ALL

        -- etldoc: osm_railway_linestring_gen3  ->  layer_transportation:z10
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_railway_linestring_gen3
        WHERE zoom_level = 10
            AND railway IN ('rail', 'narrow_gauge') AND service = ''
        UNION ALL

        -- etldoc: osm_railway_linestring_gen2  ->  layer_transportation:z11
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL as surface, z_order
        FROM osm_railway_linestring_gen2
        WHERE zoom_level = 11
            AND railway IN ('rail', 'narrow_gauge', 'light_rail') AND service = ''
        UNION ALL

        -- etldoc: osm_railway_linestring_gen1  ->  layer_transportation:z12
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL as surface, z_order
        FROM osm_railway_linestring_gen1
        WHERE zoom_level = 12
            AND railway IN ('rail', 'narrow_gauge', 'light_rail') AND service = ''
        UNION ALL

        -- etldoc: osm_railway_linestring       ->  layer_transportation:z13
        -- etldoc: osm_railway_linestring       ->  layer_transportation:z14_
        SELECT
            osm_id, geometry,
            NULL AS highway, railway, NULL AS aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL as surface, z_order
        FROM osm_railway_linestring
        WHERE zoom_level = 13
                AND railway IN ('rail', 'narrow_gauge', 'light_rail') AND service = ''
            OR zoom_Level >= 14
        UNION ALL

        -- etldoc: osm_aerialway_linestring_gen1  ->  layer_transportation:z12
        SELECT
            osm_id, geometry,
            NULL AS highway, NULL as railway, aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_aerialway_linestring_gen1
        WHERE zoom_level = 12
        UNION ALL

        -- etldoc: osm_aerialway_linestring       ->  layer_transportation:z13
        -- etldoc: osm_aerialway_linestring       ->  layer_transportation:z14_
        SELECT
            osm_id, geometry,
            NULL AS highway, NULL as railway, aerialway, NULL AS shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_aerialway_linestring
        WHERE zoom_level >= 13
        UNION ALL

        -- etldoc: osm_shipway_linestring_gen2  ->  layer_transportation:z11
        SELECT
            osm_id, geometry,
            NULL AS highway, NULL AS railway, NULL AS aerialway, shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_shipway_linestring_gen2
        WHERE zoom_level = 11
        UNION ALL

        -- etldoc: osm_shipway_linestring_gen1  ->  layer_transportation:z12
        SELECT
            osm_id, geometry,
            NULL AS highway, NULL AS railway, NULL AS aerialway, shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_shipway_linestring_gen1
        WHERE zoom_level = 12
        UNION ALL

        -- etldoc: osm_shipway_linestring       ->  layer_transportation:z13
        -- etldoc: osm_shipway_linestring       ->  layer_transportation:z14_
        SELECT
            osm_id, geometry,
            NULL AS highway, NULL AS railway, NULL AS aerialway, shipway,
            NULL AS public_transport, service_value(service) AS service,
            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, NULL as man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_shipway_linestring
        WHERE zoom_level >= 13
        UNION ALL

        -- NOTE: We limit the selection of polys because we need to be
        -- careful to net get false positives here because
        -- it is possible that closed linestrings appear both as
        -- highway linestrings and as polygon
        -- etldoc: osm_highway_polygon          ->  layer_transportation:z13
        -- etldoc: osm_highway_polygon          ->  layer_transportation:z14_
        SELECT
            osm_id, geometry,
            highway, NULL AS railway, NULL AS aerialway, NULL AS shipway,
            public_transport, NULL AS service,
            CASE WHEN man_made IN ('bridge') THEN TRUE
                ELSE FALSE
            END AS is_bridge, FALSE AS is_tunnel, FALSE AS is_ford,
            FALSE AS is_ramp, FALSE::int AS is_oneway, man_made,
            layer, NULL::int AS level, NULL::boolean AS indoor,
            NULL AS surface, z_order
        FROM osm_highway_polygon
        -- We do not want underground pedestrian areas for now
        WHERE zoom_level >= 13
            AND (
                  man_made IN ('bridge', 'pier')
                  OR (is_area AND COALESCE(layer, 0) >= 0)
            )
    ) AS zoom_levels
    WHERE geometry && bbox
    ORDER BY z_order ASC;
$$ LANGUAGE SQL IMMUTABLE;