<?php
/**
 * What:    Manages the wp_pr_r2_log table used to track every offload and
 *          remove-local operation: success, error, or skipped. Surfaces the
 *          most recent entries on the admin page for visibility.
 * Who:     PR_R2_Log::create_table() called on plugin activation.
 *          PR_R2_Log::write() called by PR_R2_Ajax after each file operation.
 *          PR_R2_Log::get_recent() called by PR_R2_Admin_Page::render().
 * Depends: WordPress $wpdb global.
 *
 * @see  includes/class-r2-ajax.php       (writes log rows after each operation)
 * @see  includes/class-r2-admin-page.php (reads log rows for display)
 * @see  peptiderepo-r2-manager.php       (register_activation_hook + self-heal)
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class PR_R2_Log {

	const TABLE_NAME   = 'pr_r2_log';
	const STATUS_OK    = 'success';
	const STATUS_ERROR = 'error';
	const STATUS_SKIP  = 'skipped';

	/**
	 * Create the log table. Uses CREATE TABLE IF NOT EXISTS for idempotency.
	 * Safe to call repeatedly — no-op if the table already exists.
	 *
	 * @return void
	 * Side effects: may CREATE wp_pr_r2_log in the WordPress database.
	 */
	public static function create_table(): void {
		global $wpdb;
		$table      = $wpdb->prefix . self::TABLE_NAME;
		$charset_cs = $wpdb->get_charset_collate();
		$wpdb->query(
			"CREATE TABLE IF NOT EXISTS {$table} (
				id            BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
				attachment_id BIGINT UNSIGNED NOT NULL DEFAULT 0,
				file_path     VARCHAR(500)    NOT NULL DEFAULT '',
				operation     VARCHAR(20)     NOT NULL DEFAULT '',
				status        ENUM('success','error','skipped') NOT NULL DEFAULT 'success',
				error_msg     TEXT,
				created_at    DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
				PRIMARY KEY (id),
				KEY idx_attachment_id (attachment_id),
				KEY idx_created_at    (created_at)
			) {$charset_cs}"
		);
	}

	/**
	 * Insert one log row.
	 *
	 * @param  int    $attachment_id  WP attachment post ID.
	 * @param  string $file_path      Relative file path (e.g. 2025/11/photo.jpg).
	 * @param  string $operation      'migrate' | 'remove-local'.
	 * @param  string $status         One of the STATUS_* constants.
	 * @param  string $error_msg      Human-readable error on failure; empty otherwise.
	 * @return void
	 * Side effects: inserts a row into wp_pr_r2_log.
	 */
	public static function write(
		int $attachment_id,
		string $file_path,
		string $operation,
		string $status,
		string $error_msg = ''
	): void {
		global $wpdb;
		$wpdb->insert(
			$wpdb->prefix . self::TABLE_NAME,
			[
				'attachment_id' => $attachment_id,
				'file_path'     => $file_path,
				'operation'     => $operation,
				'status'        => $status,
				'error_msg'     => $error_msg,
				'created_at'    => current_time( 'mysql' ),
			],
			[ '%d', '%s', '%s', '%s', '%s', '%s' ]
		);
	}

	/**
	 * Return the most recent log rows for display on the admin page.
	 *
	 * @param  int $limit  Number of rows to return (default 20).
	 * @return array<int,object>
	 */
	public static function get_recent( int $limit = 20 ): array {
		global $wpdb;
		return $wpdb->get_results( $wpdb->prepare(
			'SELECT * FROM ' . $wpdb->prefix . self::TABLE_NAME . ' ORDER BY id DESC LIMIT %d',
			$limit
		) );
	}

	/**
	 * Delete all rows from the log table.
	 *
	 * @return void
	 * Side effects: truncates wp_pr_r2_log.
	 */
	public static function clear(): void {
		global $wpdb;
		$wpdb->query( 'TRUNCATE TABLE ' . $wpdb->prefix . self::TABLE_NAME );
	}

	/**
	 * Count rows by status for a given operation.
	 *
	 * @param  string $operation  'migrate' | 'remove-local' | '' for all.
	 * @return array{success:int,error:int,skipped:int}
	 */
	public static function count_by_status( string $operation = '' ): array {
		global $wpdb;
		$table = $wpdb->prefix . self::TABLE_NAME;
		$where = $operation ? $wpdb->prepare( 'WHERE operation = %s', $operation ) : '';
		$rows  = $wpdb->get_results(
			"SELECT status, COUNT(*) AS cnt FROM {$table} {$where} GROUP BY status"
		);
		$out = [ 'success' => 0, 'error' => 0, 'skipped' => 0 ];
		foreach ( $rows as $row ) {
			$out[ $row->status ] = (int) $row->cnt;
		}
		return $out;
	}
}