-- Fix collation inconsistency on saved_filters and ticket_attachments
--
-- README.md Developer Notes #12: "Database collation: Use
-- utf8mb4_general_ci (not unicode_ci) for new tables." These two tables
-- were created with utf8mb4_unicode_ci instead, inconsistent with every
-- other table in the schema. Mixed collations don't break anything by
-- themselves, but any future query joining/comparing these columns
-- against general_ci columns needs explicit COLLATE casts or hits
-- "Illegal mix of collations" errors.
--
-- Safe to re-run.

ALTER TABLE `saved_filters`
    CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

-- saved_filters.filter_criteria is pinned to utf8mb4_bin (for the
-- json_valid() CHECK constraint) — restore that after the table-wide
-- CONVERT TO above, which resets it to general_ci. MariaDB drops the
-- inline CHECK when the column is MODIFYed, so re-add it explicitly.
ALTER TABLE `saved_filters`
    MODIFY COLUMN `filter_criteria` longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL;

ALTER TABLE `saved_filters`
    DROP CONSTRAINT IF EXISTS `saved_filters_filter_criteria_json`;

ALTER TABLE `saved_filters`
    ADD CONSTRAINT `saved_filters_filter_criteria_json` CHECK (json_valid(`filter_criteria`));

ALTER TABLE `ticket_attachments`
    CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;