<?php
/**
 * Database migration for conversations table
 *
 * @package WP_Agentic_Writer
 */

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

/**
 * Create the conversations table
 *
 * @since 0.1.4
 */
function wpaw_create_conversations_table()
{
    global $wpdb;

    $table_name = $wpdb->prefix . "wpaw_conversations";
    $charset_collate = $wpdb->get_charset_collate();

    $sql = "CREATE TABLE IF NOT EXISTS {$table_name} (
		id BIGINT AUTO_INCREMENT PRIMARY KEY,
		session_id VARCHAR(32) NOT NULL UNIQUE,
		user_id BIGINT NOT NULL,
		post_id BIGINT DEFAULT 0,
		title VARCHAR(255) DEFAULT '',
		focus_keyword VARCHAR(255) DEFAULT '',
		messages LONGTEXT,
		context LONGTEXT,
		status ENUM('active', 'completed', 'archived') DEFAULT 'active',
		created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
		updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
		INDEX idx_user_status (user_id, status),
		INDEX idx_post_id (post_id),
		INDEX idx_session_id (session_id)
	) {$charset_collate};";

    require_once ABSPATH . "wp-admin/includes/upgrade.php";
    dbDelta($sql);

    // Migrate session_id column width for UUID support (UUID v4 is 36 chars vs old MD5 32)
    $wpdb->query(
        "ALTER TABLE {$table_name} MODIFY session_id VARCHAR(36) NOT NULL",
    );

    // Store conversation table migration version (don't override main db version)
    $existing_version = get_option("wpaw_conversations_db_version", "0");
    if (version_compare($existing_version, "0.1.4", "<")) {
        update_option("wpaw_conversations_db_version", "0.1.4");
    }
}

/**
 * Drop the conversations table (for testing/reset)
 *
 * @since 0.1.4
 */
function wpaw_drop_conversations_table()
{
    global $wpdb;
    $table_name = $wpdb->prefix . "wpaw_conversations";
    $wpdb->query("DROP TABLE IF EXISTS {$table_name}");
    delete_option("wpaw_conversations_db_version");
}

/**
 * Run migrations on plugin activation
 *
 * @since 0.1.4
 */
function wpaw_run_migrations()
{
    $current_version = get_option("wpaw_conversations_db_version", "0");

    if (version_compare($current_version, "0.1.4", "<")) {
        wpaw_create_conversations_table();
    }

    if (version_compare($current_version, "0.2.0", "<")) {
        wpaw_add_edit_lock_column();
    }
}

/**
 * Cleanup old orphaned sessions (cron job)
 * Archives sessions inactive for 30+ days
 *
 * @since 0.1.4
 */
function wpaw_cleanup_old_sessions()
{
    global $wpdb;
    $table_name = $wpdb->prefix . "wpaw_conversations";

    // Archive sessions with no post_id and inactive for 30 days
    $wpdb->query(
        $wpdb->prepare(
            "UPDATE {$table_name} SET status = 'archived' WHERE status = 'active' AND post_id = 0 AND updated_at < %s",
            date("Y-m-d H:i:s", strtotime("-30 days")),
        ),
    );
}

/**
 * Add edit_lock column to conversations table.
 *
 * @since 0.2.0
 */
function wpaw_add_edit_lock_column()
{
    global $wpdb;

    $table_name = $wpdb->prefix . "wpaw_conversations";

    // Check if column already exists (idempotent).
    $column_exists = $wpdb->get_results(
        $wpdb->prepare("SHOW COLUMNS FROM {$table_name} LIKE %s", "edit_lock"),
    );

    if (empty($column_exists)) {
        $wpdb->query(
            "ALTER TABLE {$table_name} ADD COLUMN edit_lock VARCHAR(64) DEFAULT NULL",
        );
    }

    update_option("wpaw_conversations_db_version", "0.2.0");
}

// Register cron job for cleanup
add_action("wpaw_cleanup_old_sessions", "wpaw_cleanup_old_sessions");

if (!wp_next_scheduled("wpaw_cleanup_old_sessions")) {
    wp_schedule_event(time(), "daily", "wpaw_cleanup_old_sessions");
}