<?php
/**
 * Database schema creation and versioned migrations.
 *
 * @package MediaRightsAudit\Core
 */

namespace MediaRightsAudit\Core;

/**
 * Manages all custom table creation and schema migrations.
 *
 * Migration methods are idempotent: they rely on dbDelta's ALTER TABLE
 * diffing and can be run multiple times without side effects.
 */
class Database {

	/**
	 * Creates all tables. Called on plugin activation.
	 *
	 * @return void
	 */
	public static function create_tables(): void {
		self::migration_100();
		self::migration_101();
		self::migration_110();
		self::migration_120();
	}

	/**
	 * Applies any pending migrations based on the currently installed schema version.
	 *
	 * Called on admin_init by Plugin::check_db_version().
	 *
	 * @return void
	 */
	public static function run_migrations(): void {
		$raw     = get_option( 'robotstxt_mediaaudit_db_version', '0.0.0' );
		$current = is_string( $raw ) ? $raw : '0.0.0';

		if ( version_compare( $current, '1.0.0', '<' ) ) {
			self::migration_100();
		}

		if ( version_compare( $current, '1.0.1', '<' ) ) {
			self::migration_101();
		}

		if ( version_compare( $current, '1.1.0', '<' ) ) {
			self::migration_110();
		}

		if ( version_compare( $current, '1.2.0', '<' ) ) {
			self::migration_120();
		}
	}

	/**
	 * Drops all plugin tables. Used by uninstall.php.
	 *
	 * @return void
	 */
	public static function drop_tables(): void {
		global $wpdb;
		$wpdb->query( "DROP TABLE IF EXISTS `{$wpdb->prefix}mra_dismissed_alerts`" ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->query( "DROP TABLE IF EXISTS `{$wpdb->prefix}mra_provider_status`" );  // phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->query( "DROP TABLE IF EXISTS `{$wpdb->prefix}mra_external_results`" ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->query( "DROP TABLE IF EXISTS `{$wpdb->prefix}mra_media_usage`" );      // phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$wpdb->query( "DROP TABLE IF EXISTS `{$wpdb->prefix}mra_media_index`" );      // phpcs:ignore WordPress.DB.DirectDatabaseQuery
	}

	/**
	 * Truncates all plugin tables, removing all data while preserving the table structure.
	 *
	 * Used by the Tools page "Reset all data" operation.
	 *
	 * @return void
	 */
	public static function truncate_all(): void {
		global $wpdb;

		// phpcs:disable WordPress.DB.DirectDatabaseQuery
		$wpdb->query( "TRUNCATE TABLE `{$wpdb->prefix}mra_dismissed_alerts`" );
		$wpdb->query( "TRUNCATE TABLE `{$wpdb->prefix}mra_provider_status`" );
		$wpdb->query( "TRUNCATE TABLE `{$wpdb->prefix}mra_external_results`" );
		$wpdb->query( "TRUNCATE TABLE `{$wpdb->prefix}mra_media_usage`" );
		$wpdb->query( "TRUNCATE TABLE `{$wpdb->prefix}mra_media_index`" );
		// phpcs:enable WordPress.DB.DirectDatabaseQuery
	}

	// -------------------------------------------------------------------------
	// Migrations
	// -------------------------------------------------------------------------

	/**
	 * Migration 1.0.0 — creates the initial three tables.
	 *
	 * @return void
	 */
	private static function migration_100(): void {
		global $wpdb;

		$charset_collate = $wpdb->get_charset_collate();

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		dbDelta(
			"CREATE TABLE {$wpdb->prefix}mra_media_index (
  attachment_id bigint(20) unsigned NOT NULL,
  file_url text NOT NULL,
  file_name varchar(255) NOT NULL DEFAULT '',
  mime_type varchar(100) NOT NULL DEFAULT '',
  file_size bigint(20) unsigned NOT NULL DEFAULT 0,
  internal_scanned_at datetime DEFAULT NULL,
  external_status enum('pending','queued','scanned','matches','error') NOT NULL DEFAULT 'pending',
  external_scanned_at datetime DEFAULT NULL,
  created_at datetime NOT NULL,
  PRIMARY KEY  (attachment_id),
  KEY external_status (external_status)
) {$charset_collate};"
		);

		dbDelta(
			"CREATE TABLE {$wpdb->prefix}mra_media_usage (
  usage_id bigint(20) unsigned NOT NULL auto_increment,
  attachment_id bigint(20) unsigned NOT NULL,
  post_id bigint(20) unsigned NOT NULL,
  post_type varchar(20) NOT NULL DEFAULT '',
  context enum('featured','content','meta') NOT NULL DEFAULT 'featured',
  meta_key varchar(255) DEFAULT NULL,
  created_at datetime NOT NULL,
  PRIMARY KEY  (usage_id),
  KEY attachment_id (attachment_id),
  KEY post_id (post_id)
) {$charset_collate};"
		);

		dbDelta(
			"CREATE TABLE {$wpdb->prefix}mra_external_results (
  result_id bigint(20) unsigned NOT NULL auto_increment,
  attachment_id bigint(20) unsigned NOT NULL,
  provider varchar(100) NOT NULL,
  raw_response json DEFAULT NULL,
  match_count int(10) unsigned NOT NULL DEFAULT 0,
  top_domains json DEFAULT NULL,
  created_at datetime NOT NULL,
  PRIMARY KEY  (result_id),
  UNIQUE KEY attachment_provider (attachment_id,provider)
) {$charset_collate};"
		);
	}

	/**
	 * Migration 1.0.1 — adds 'queued' to the external_status ENUM.
	 *
	 * Uses ALTER TABLE directly because dbDelta cannot modify ENUM column definitions.
	 * Safe to re-run: MariaDB/MySQL treats an identical MODIFY as a no-op.
	 *
	 * @return void
	 */
	private static function migration_101(): void {
		global $wpdb;

		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.DirectDatabaseQuery.SchemaChange
		$wpdb->query(
			"ALTER TABLE `{$wpdb->prefix}mra_media_index`
			 MODIFY COLUMN external_status
			 enum('pending','queued','scanned','matches','error') NOT NULL DEFAULT 'pending'"
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery,WordPress.DB.DirectDatabaseQuery.SchemaChange
	}

	/**
	 * Migration 1.1.0 — widens provider column and adds mra_provider_status table.
	 *
	 * Changes:
	 * - ALTER mra_external_results.provider from ENUM to varchar(100) for extensibility.
	 * - CREATE mra_provider_status for per-provider scan tracking.
	 * - Backfill mra_provider_status from existing mra_external_results data.
	 *
	 * Safe to re-run: ALTER TABLE is a no-op if already varchar(100);
	 * dbDelta skips existing tables; INSERT IGNORE skips duplicate rows.
	 *
	 * @return void
	 */
	private static function migration_110(): void {
		global $wpdb;

		$charset_collate = $wpdb->get_charset_collate();

		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.DirectDatabaseQuery.SchemaChange
		$wpdb->query(
			"ALTER TABLE `{$wpdb->prefix}mra_external_results`
			 MODIFY COLUMN provider varchar(100) NOT NULL"
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery,WordPress.DB.DirectDatabaseQuery.SchemaChange

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		dbDelta(
			"CREATE TABLE {$wpdb->prefix}mra_provider_status (
  attachment_id bigint(20) unsigned NOT NULL,
  provider varchar(100) NOT NULL,
  status enum('pending','queued','scanned','error') NOT NULL DEFAULT 'pending',
  scanned_at datetime DEFAULT NULL,
  PRIMARY KEY  (attachment_id,provider),
  KEY status (status)
) {$charset_collate};"
		);

		// Backfill from existing data. Idempotent: INSERT IGNORE skips duplicates.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$wpdb->query(
			"INSERT IGNORE INTO {$wpdb->prefix}mra_provider_status (attachment_id, provider, status, scanned_at)
			 SELECT er.attachment_id, er.provider,
			   CASE WHEN mi.external_status = 'error' THEN 'error'
			        WHEN mi.external_status = 'queued' THEN 'queued'
			        ELSE 'scanned' END,
			   mi.external_scanned_at
			 FROM {$wpdb->prefix}mra_external_results er
			 JOIN {$wpdb->prefix}mra_media_index mi ON mi.attachment_id = er.attachment_id"
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
	}

	/**
	 * Migration 1.2.0 — creates the mra_dismissed_alerts table.
	 *
	 * Stores per-attachment alert dismissal records with dismisser, timestamp,
	 * and optional notes. Primary key on attachment_id (one dismissal per image).
	 *
	 * Safe to re-run: dbDelta skips existing tables.
	 *
	 * @return void
	 */
	private static function migration_120(): void {
		global $wpdb;

		$charset_collate = $wpdb->get_charset_collate();

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		dbDelta(
			"CREATE TABLE {$wpdb->prefix}mra_dismissed_alerts (
  attachment_id bigint(20) unsigned NOT NULL,
  dismissed_by bigint(20) unsigned NOT NULL DEFAULT 0,
  dismissed_at datetime NOT NULL,
  notes text NOT NULL DEFAULT '',
  PRIMARY KEY  (attachment_id)
) {$charset_collate};"
		);
	}
}