DROP TRIGGER IF EXISTS trigger_flag ON osm_country_point;
DROP TRIGGER IF EXISTS trigger_refresh ON place_country.updates;

ALTER TABLE osm_country_point
    DROP CONSTRAINT IF EXISTS osm_country_point_rank_constraint;

-- etldoc: ne_10m_admin_0_countries   -> osm_country_point
-- etldoc: osm_country_point          -> osm_country_point

CREATE OR REPLACE FUNCTION update_osm_country_point() RETURNS void AS
$$
BEGIN

    UPDATE osm_country_point AS osm
    SET "rank"            = 7,
        iso3166_1_alpha_2 = COALESCE(
                NULLIF(osm.country_code_iso3166_1_alpha_2, ''),
                NULLIF(osm.iso3166_1_alpha_2, ''),
                NULLIF(osm.iso3166_1, '')
            );

    WITH important_country_point AS (
        SELECT osm.geometry,
               osm.osm_id,
               osm.name,
               COALESCE(NULLIF(osm.name_en, ''), ne.name) AS name_en,
               ne.scalerank,
               ne.labelrank
        FROM ne_10m_admin_0_countries AS ne,
             osm_country_point AS osm
        WHERE
          -- We match only countries with ISO codes to eliminate disputed countries
            iso3166_1_alpha_2 IS NOT NULL
          -- that lies inside polygon of sovereign country
          AND ST_Within(osm.geometry, ne.geometry)
    )
    UPDATE osm_country_point AS osm
        -- Normalize both scalerank and labelrank into a ranking system from 1 to 6
        -- where the ranks are still distributed uniform enough across all countries
    SET "rank" = LEAST(6, CEILING((scalerank + labelrank) / 2.0))
    FROM important_country_point AS ne
    WHERE osm.osm_id = ne.osm_id;

    -- Repeat the step for archipelago countries like Philippines or Indonesia
    -- whose label point is not within country's polygon
    WITH important_country_point AS (
        SELECT osm.osm_id,
--       osm.name,
               ne.scalerank,
               ne.labelrank,
--       ST_Distance(osm.geometry, ne.geometry) AS distance,
               ROW_NUMBER()
               OVER (
                   PARTITION BY osm.osm_id
                   ORDER BY
                       ST_Distance(osm.geometry, ne.geometry)
                   ) AS rk
        FROM osm_country_point osm,
             ne_10m_admin_0_countries AS ne
        WHERE iso3166_1_alpha_2 IS NOT NULL
          AND NOT (osm."rank" BETWEEN 1 AND 6)
    )
    UPDATE osm_country_point AS osm
        -- Normalize both scalerank and labelrank into a ranking system from 1 to 6
        -- where the ranks are still distributed uniform enough across all countries
    SET "rank" = LEAST(6, CEILING((ne.scalerank + ne.labelrank) / 2.0))
    FROM important_country_point AS ne
    WHERE osm.osm_id = ne.osm_id
      AND ne.rk = 1;

    UPDATE osm_country_point AS osm
    SET "rank" = 6
    WHERE "rank" = 7;

    -- TODO: This shouldn't be necessary? The rank function makes something wrong...
    UPDATE osm_country_point AS osm
    SET "rank" = 1
    WHERE "rank" = 0;

    UPDATE osm_country_point
    SET tags = update_tags(tags, geometry)
    WHERE COALESCE(tags->'name:latin', tags->'name:nonlatin', tags->'name_int') IS NULL;

END;
$$ LANGUAGE plpgsql;

SELECT update_osm_country_point();

-- ALTER TABLE osm_country_point ADD CONSTRAINT osm_country_point_rank_constraint CHECK("rank" BETWEEN 1 AND 6);
CREATE INDEX IF NOT EXISTS osm_country_point_rank_idx ON osm_country_point ("rank");

-- Handle updates

CREATE SCHEMA IF NOT EXISTS place_country;

CREATE TABLE IF NOT EXISTS place_country.updates
(
    id serial PRIMARY KEY,
    t  text,
    UNIQUE (t)
);
CREATE OR REPLACE FUNCTION place_country.flag() RETURNS trigger AS
$$
BEGIN
    INSERT INTO place_country.updates(t) VALUES ('y') ON CONFLICT(t) DO NOTHING;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION place_country.refresh() RETURNS trigger AS
$$
BEGIN
    RAISE LOG 'Refresh place_country rank';
    PERFORM update_osm_country_point();
    -- noinspection SqlWithoutWhere
    DELETE FROM place_country.updates;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_flag
    AFTER INSERT OR UPDATE OR DELETE
    ON osm_country_point
    FOR EACH STATEMENT
EXECUTE PROCEDURE place_country.flag();

CREATE CONSTRAINT TRIGGER trigger_refresh
    AFTER INSERT
    ON place_country.updates
    INITIALLY DEFERRED
    FOR EACH ROW
EXECUTE PROCEDURE place_country.refresh();
