-- Suppliers become a full mirror of the customers model: dedicated
-- contact_person/email/phone/notes columns are replaced by the same
-- custom_fields JSON blob customers use ({"fields":[{name,value,showLabel}],
-- "field_order":[]}). Existing contact data is preserved as custom fields.

-- AlterTable: add the custom_fields blob
ALTER TABLE `sklad_suppliers` ADD COLUMN `custom_fields` LONGTEXT NULL AFTER `country`;

-- Seed an empty container for rows that carry any contact data
UPDATE `sklad_suppliers`
SET `custom_fields` = JSON_OBJECT('fields', JSON_ARRAY(), 'field_order', JSON_ARRAY())
WHERE COALESCE(`contact_person`, '') <> ''
   OR COALESCE(`email`, '') <> ''
   OR COALESCE(`phone`, '') <> ''
   OR COALESCE(`notes`, '') <> '';

-- Preserve data: each legacy column becomes one labeled custom field
UPDATE `sklad_suppliers`
SET `custom_fields` = JSON_ARRAY_APPEND(`custom_fields`, '$.fields',
  JSON_OBJECT('name', 'Kontaktní osoba', 'value', `contact_person`, 'showLabel', TRUE))
WHERE COALESCE(`contact_person`, '') <> '';

UPDATE `sklad_suppliers`
SET `custom_fields` = JSON_ARRAY_APPEND(`custom_fields`, '$.fields',
  JSON_OBJECT('name', 'E-mail', 'value', `email`, 'showLabel', TRUE))
WHERE COALESCE(`email`, '') <> '';

UPDATE `sklad_suppliers`
SET `custom_fields` = JSON_ARRAY_APPEND(`custom_fields`, '$.fields',
  JSON_OBJECT('name', 'Telefon', 'value', `phone`, 'showLabel', TRUE))
WHERE COALESCE(`phone`, '') <> '';

UPDATE `sklad_suppliers`
SET `custom_fields` = JSON_ARRAY_APPEND(`custom_fields`, '$.fields',
  JSON_OBJECT('name', 'Poznámky', 'value', `notes`, 'showLabel', TRUE))
WHERE COALESCE(`notes`, '') <> '';

-- AlterTable: drop the dedicated columns
ALTER TABLE `sklad_suppliers`
  DROP COLUMN `contact_person`,
  DROP COLUMN `email`,
  DROP COLUMN `phone`,
  DROP COLUMN `notes`;