--
-- Scrape cache + per-attachment scrape lifecycle.
--
-- HOW THIS IS APPLIED
--
--   ./applyScrapeSchema.sh      (from the repo root, as an admin)
--
-- Run it once per environment. The application does NOT apply this itself:
-- production connects as a least-privilege `app` user with DML rights only, and
-- deliberately holds no CREATE/ALTER. server/helpers/Schema.js only *verifies*
-- that these objects exist and that the required privileges are held; if they
-- are missing it disables link previews and logs the remedy.
--
-- Safe to re-run: every statement is conditional.
--
-- Portability: dev and production are both MariaDB 11.4, so ADD COLUMN IF NOT
-- EXISTS and CREATE INDEX IF NOT EXISTS are available. If this project ever
-- moves to MySQL 8 these become invalid and need information_schema guards
-- instead.
--

-- One row per URL, shared across users and notes.
--
-- url_hash carries the UNIQUE index because a UNIQUE on varchar(1000) utf8mb4
-- is 4000 bytes and exceeds InnoDB's 3072-byte key limit. `url` is kept
-- human-readable for debugging only.
--
-- COLLATE is stated explicitly to match the existing tables (utf8mb4_general_ci)
-- rather than inheriting whatever the server default happens to be.
CREATE TABLE IF NOT EXISTS `scrape_cache` (
  `id`            int(10) unsigned NOT NULL AUTO_INCREMENT,
  `url_hash`      char(64) NOT NULL,
  `url`           varchar(1000) NOT NULL DEFAULT '',
  `canonical_url` varchar(1000) DEFAULT NULL,
  `status`        smallint(6) NOT NULL DEFAULT 0,
  `title`         varchar(512) DEFAULT NULL,
  `site_name`     varchar(255) DEFAULT NULL,
  `description`   mediumtext DEFAULT NULL,
  `keywords`      varchar(512) DEFAULT NULL,
  `search_text`   mediumtext DEFAULT NULL,
  `image_url`     varchar(1000) DEFAULT NULL,
  `file_location` varchar(500) DEFAULT NULL,
  `etag`          varchar(255) DEFAULT NULL,
  `last_modified` varchar(128) DEFAULT NULL,
  `content_type`  varchar(128) DEFAULT NULL,
  `fetch_state`   varchar(20) NOT NULL DEFAULT 'pending',
  `failure_count` int(11) NOT NULL DEFAULT 0,
  `last_error`    varchar(255) DEFAULT NULL,
  `fetched_at`    int(11) DEFAULT NULL,
  `expires_at`    int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `scrape_cache_url_hash` (`url_hash`),
  KEY `scrape_cache_expires_at` (`expires_at`),
  KEY `scrape_cache_fetch_state` (`fetch_state`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

-- Per-attachment lifecycle, so the in-memory scrape queue survives a restart.
--
-- scrape_state: 0 = pending, 1 = fetching, 2 = done, 3 = failed.
--
-- DEFAULT 2 is load-bearing: it keeps every pre-existing attachment row
-- (~2200 in production) out of the boot recovery sweep.
ALTER TABLE `attachment` ADD COLUMN IF NOT EXISTS `scrape_state`    tinyint(4) NOT NULL DEFAULT 2;
ALTER TABLE `attachment` ADD COLUMN IF NOT EXISTS `scrape_attempts` tinyint(4) NOT NULL DEFAULT 0;
ALTER TABLE `attachment` ADD COLUMN IF NOT EXISTS `enqueued_at`     int(11) DEFAULT NULL;

CREATE INDEX IF NOT EXISTS `attachment_scrape_state` ON `attachment` (`scrape_state`, `enqueued_at`);