DROP VIEW IF EXISTS v_animals_weight_alerts;

CREATE VIEW v_animals_weight_alerts AS
SELECT
  a.id AS animal_id,

  -- dernier poids
  (
    SELECT m.value
    FROM measurements m
    WHERE m.animal_id=a.id AND m.type='weight'
    ORDER BY m.id DESC
    LIMIT 1
  ) AS last_weight,

  -- poids de référence ~30 jours avant : le plus récent <= J-30
  (
    SELECT m.value
    FROM measurements m
    WHERE m.animal_id=a.id AND m.type='weight'
      AND date(m.measured_at) <= date('now','-30 day')
    ORDER BY date(m.measured_at) DESC, m.id DESC
    LIMIT 1
  ) AS w30_weight,

  (
    SELECT m.measured_at
    FROM measurements m
    WHERE m.animal_id=a.id AND m.type='weight'
      AND date(m.measured_at) <= date('now','-30 day')
    ORDER BY date(m.measured_at) DESC, m.id DESC
    LIMIT 1
  ) AS w30_date
FROM animals a;