BEGIN;

CREATE TABLE party_role (
  party_id BIGINT NOT NULL REFERENCES party(id) ON DELETE CASCADE,
  role_code TEXT NOT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT NOW(),
  CONSTRAINT pk_party_role PRIMARY KEY (party_id, role_code),
  CONSTRAINT chk_party_role_code CHECK (role_code IN ('manufacturer'))
);

CREATE INDEX idx_party_role_code ON party_role(role_code);

ALTER TABLE stock_lot
  RENAME COLUMN supplier_lot_number TO manufacturer_lot_number;

ALTER TABLE stock_lot
  ADD COLUMN manufacturer_party_id BIGINT REFERENCES party(id) ON DELETE RESTRICT;

INSERT INTO party (type, name, status, created_at, updated_at)
SELECT 'supplier', MIN(TRIM(supplier_name)), 'active', NOW(), NOW()
FROM stock_lot
WHERE supplier_name IS NOT NULL
  AND TRIM(supplier_name) <> ''
  AND NOT EXISTS (
    SELECT 1
    FROM party p
    WHERE LOWER(TRIM(p.name)) = LOWER(TRIM(stock_lot.supplier_name))
  )
GROUP BY LOWER(TRIM(supplier_name));

INSERT INTO party_role (party_id, role_code)
SELECT p.id, 'manufacturer'
FROM party p
WHERE EXISTS (
    SELECT 1
    FROM stock_lot sl
    WHERE sl.supplier_name IS NOT NULL
      AND LOWER(TRIM(sl.supplier_name)) = LOWER(TRIM(p.name))
  )
ON CONFLICT (party_id, role_code) DO NOTHING;

UPDATE stock_lot sl
SET manufacturer_party_id = p.id
FROM party p
WHERE sl.supplier_name IS NOT NULL
  AND LOWER(TRIM(sl.supplier_name)) = LOWER(TRIM(p.name));

ALTER TABLE stock_lot
  DROP COLUMN supplier_name;

CREATE INDEX idx_stock_lot_manufacturer_party ON stock_lot(manufacturer_party_id);

COMMIT;