-- City dimension: canonical city records with population and venue count.
-- Built from Eurostat Urban Audit codes joined to venue locations.
-- Cities without Eurostat coverage (US, non-EU) are derived from venue clusters.

MODEL (
  name foundation.dim_cities,
  kind FULL,
  cron '@daily',
  grain city_code
);

WITH -- Eurostat cities: latest population per city code
eurostat_cities AS (
  SELECT
    city_code,
    country_code,
    population,
    ref_year
  FROM staging.stg_population
  QUALIFY ROW_NUMBER() OVER (PARTITION BY city_code ORDER BY ref_year DESC) = 1
),
-- Venue counts per (country_code, city) from dim_venues
venue_counts AS (
  SELECT
    country_code,
    city,
    COUNT(*)  AS venue_count,
    AVG(lat)  AS centroid_lat,
    AVG(lon)  AS centroid_lon
  FROM foundation.dim_venues
  WHERE city IS NOT NULL AND city != ''
  GROUP BY country_code, city
),
-- Eurostat city label mapping to canonical city names
-- (Eurostat uses codes like DE001C → Berlin; we keep both)
eurostat_labels AS (
  SELECT DISTINCT
    city_code,
    country_code,
    -- Derive a slug-friendly city name from the code as fallback
    LOWER(REPLACE(city_code, country_code, ''))  AS city_slug_raw
  FROM eurostat_cities
)
SELECT
  ec.city_code,
  ec.country_code,
  COALESCE(vc.city, ec.city_code)               AS city_name,
  LOWER(REGEXP_REPLACE(
    COALESCE(vc.city, ec.city_slug_raw), '[^a-z0-9]+', '-'
  ))                                             AS city_slug,
  COALESCE(vc.centroid_lat, 0::DOUBLE)           AS lat,
  COALESCE(vc.centroid_lon, 0::DOUBLE)           AS lon,
  ec.population,
  ec.ref_year                                    AS population_year,
  COALESCE(vc.venue_count, 0)                    AS padel_venue_count
FROM eurostat_cities ec
LEFT JOIN venue_counts vc
  ON  ec.country_code = vc.country_code
  AND LOWER(TRIM(vc.city)) LIKE '%' || LOWER(LEFT(ec.city_code, 2)) || '%'